/* Low-level bidirectional buffer/string-scanning functions for GNU Emacs.
- Copyright (C) 2000-2001, 2004-2005, 2009-2014 Free Software
+ Copyright (C) 2000-2001, 2004-2005, 2009-2015 Free Software
Foundation, Inc.
This file is part of GNU Emacs.
A sequential implementation of the Unicode Bidirectional algorithm,
(UBA) as per UAX#9, a part of the Unicode Standard.
- Unlike the reference and most other implementations, this one is
- designed to be called once for every character in the buffer or
- string.
+ Unlike the Reference Implementation and most other implementations,
+ this one is designed to be called once for every character in the
+ buffer or string. That way, we can leave intact the design of the
+ Emacs display engine, whereby an iterator object is used to
+ traverse buffer or string text character by character, and generate
+ the necessary data for displaying each character in 'struct glyph'
+ objects. (See xdisp.c for the details of that iteration.) The
+ functions on this file replace the original linear iteration in the
+ logical order of the text with a non-linear iteration in the visual
+ order, i.e. in the order characters should be shown on display.
The main entry point is bidi_move_to_visually_next. Each time it
is called, it finds the next character in the visual order, and
A note about references to UAX#9 rules: if the reference says
something like "X9/Retaining", it means that you need to refer to
rule X9 and to its modifications described in the "Implementation
- Notes" section of UAX#9, under "Retaining Format Codes". */
+ Notes" section of UAX#9, under "Retaining Format Codes".
+
+ Here's the overview of the design of the reordering engine
+ implemented by this file.
+
+ Basic implementation structure
+ ------------------------------
+
+ The sequential processing steps described by UAX#9 are implemented
+ as recursive levels of processing, all of which examine the next
+ character in the logical order. This hierarchy of processing looks
+ as follows, from the innermost (deepest) to the outermost level,
+ omitting some subroutines used by each level:
+
+ bidi_fetch_char -- fetch next character
+ bidi_resolve_explicit -- resolve explicit levels and directions
+ bidi_resolve_weak -- resolve weak types
+ bidi_resolve_brackets -- resolve "paired brackets" neutral types
+ bidi_resolve_neutral -- resolve neutral types
+ bidi_level_of_next_char -- resolve implicit levels
+
+ Each level calls the level below it, and works on the result
+ returned by the lower level, including all of its sub-levels.
+
+ Unlike all the levels below it, bidi_level_of_next_char can return
+ the information about either the next or previous character in the
+ logical order, depending on the current direction of scanning the
+ buffer or string. For the next character, it calls all the levels
+ below it; for the previous character, it uses the cache, described
+ below.
+
+ Thus, the result of calling bidi_level_of_next_char is the resolved
+ level of the next or the previous character in the logical order.
+ Based on this information, the function bidi_move_to_visually_next
+ finds the next character in the visual order and updates the
+ direction in which the buffer is scanned, either forward or
+ backward, to find the next character to be displayed. (Text is
+ scanned backwards when it needs to be reversed for display, i.e. if
+ the visual order is the inverse of the logical order.) This
+ implements the last, reordering steps of the UBA, by successively
+ calling bidi_level_of_next_char until the character of the required
+ embedding level is found; the scan direction is dynamically updated
+ as a side effect. See the commentary before the 'while' loop in
+ bidi_move_to_visually_next, for the details.
+
+ Fetching characters
+ -------------------
+
+ In a nutshell, fetching the next character boils down to calling
+ STRING_CHAR_AND_LENGTH, passing it the address of a buffer or
+ string position. See bidi_fetch_char. However, if the next
+ character is "covered" by a display property of some kind,
+ bidi_fetch_char returns the u+FFFC "object replacement character"
+ that represents the entire run of text covered by the display
+ property. (The ch_len and nchars members of 'struct bidi_it'
+ reflect the length in bytes and characters of that text.) This is
+ so we reorder text on both sides of the display property as
+ appropriate for an image or embedded string. Similarly, text
+ covered by a display spec of the form '(space ...)', is replaced
+ with the u+2029 paragraph separator character, so such display
+ specs produce the same effect as a TAB under UBA. Both these
+ special characters are not actually displayed -- the display
+ property is displayed instead -- but just used to compute the
+ embedding level of the surrounding text so as to produce the
+ required effect.
+
+ Bidi iterator states
+ --------------------
+
+ The UBA is highly context dependent in some of its parts,
+ i.e. results of processing a character can generally depend on
+ characters very far away. The UAX#9 description of the UBA
+ prescribes a stateful processing of each character, whereby the
+ results of this processing depend on various state variables, such
+ as the current embedding level, level stack, and directional
+ override status. In addition, the UAX#9 description includes many
+ passages like this (from rule W2 in this case):
+
+ Search backward from each instance of a European number until the
+ first strong type (R, L, AL, or sos) is found. If an AL is found,
+ change the type of the European number to Arabic number.
+
+ To support this, we use a bidi iterator object, 'struct bidi_it',
+ which is a sub-structure of 'struct it' used by xdisp.c (see
+ dispextern.h for the definition of both of these structures). The
+ bidi iterator holds the entire state of the iteration required by
+ the UBA, and is updated as the text is traversed. In particular,
+ the embedding level of the current character being resolved is
+ recorded in the iterator state. To avoid costly searches backward
+ in support of rules like W2 above, the necessary character types
+ are also recorded in the iterator state as they are found during
+ the forward scan, and then used when such rules need to be applied.
+ (Forward scans cannot be avoided in this way; they need to be
+ performed at least once, and the results recorded in the iterator
+ state, to be reused until the forward scan oversteps the recorded
+ position.)
+
+ In this manner, the iterator state acts as a mini-cache of
+ contextual information required for resolving the level of the
+ current character by various UBA rules.
+
+ Caching of bidi iterator states
+ -------------------------------
+
+ As described above, the reordering engine uses the information
+ recorded in the bidi iterator state in order to resolve the
+ embedding level of the current character. When the reordering
+ engine needs to process the next character in the logical order, it
+ fetches it and applies to it all the UBA levels, updating the
+ iterator state as it goes. But when the buffer or string is
+ scanned backwards, i.e. in the reverse order of buffer/string
+ positions, the scanned characters were already processed during the
+ preceding forward scan (see bidi_find_other_level_edge). To avoid
+ costly re-processing of characters that were already processed
+ during the forward scan, the iterator states computed while
+ scanning forward are cached.
+
+ The cache is just a linear array of 'struct bidi_it' objects, which
+ is dynamically allocated and reallocated as needed, since the size
+ of the cache depends on the text being processed. We only need the
+ cache while processing embedded levels higher than the base
+ paragraph embedding level, because these higher levels require
+ changes in scan direction. Therefore, as soon as we are back to
+ the base embedding level, we can free the cache; see the calls to
+ bidi_cache_reset and bidi_cache_shrink, for the conditions to do
+ this.
+
+ The cache maintains the index of the next unused cache slot -- this
+ is where the next iterator state will be cached. The function
+ bidi_cache_iterator_state saves an instance of the state in the
+ cache and increments the unused slot index. The companion function
+ bidi_cache_find looks up a cached state that corresponds to a given
+ buffer/string position. All of the cached states must correspond
+ 1:1 to the buffer or string region whose processing they reflect;
+ bidi.c will abort if it finds cache slots that violate this 1:1
+ correspondence.
+
+ When the parent iterator 'struct it' is pushed (see push_it in
+ xdisp.c) to pause the current iteration and start iterating over a
+ different object (e.g., a 'display' string that covers some buffer
+ text), the bidi iterator cache needs to be "pushed" as well, so
+ that a new empty cache could be used while iterating over the new
+ object. Later, when the new object is exhausted, and xdisp.c calls
+ pop_it, we need to "pop" the bidi cache as well and return to the
+ original cache. See bidi_push_it and bidi_pop_it for how this is
+ done.
+
+ Some functions of the display engine save copies of 'struct it' in
+ local variables, and restore them later. For examples, see
+ pos_visible_p and move_it_in_display_line_to in xdisp.c, and
+ window_scroll_pixel_based in window.c. When this happens, we need
+ to save and restore the bidi cache as well, because conceptually
+ the cache is part of the 'struct it' state, and needs to be in
+ perfect sync with the portion of the buffer/string that is being
+ processed. This saving and restoring of the cache state is handled
+ by bidi_shelve_cache and bidi_unshelve_cache, and the helper macros
+ SAVE_IT and RESTORE_IT defined on xdisp.c.
+
+ Note that, because reordering is implemented below the level in
+ xdisp.c that breaks glyphs into screen lines, we are violating
+ paragraph 3.4 of UAX#9. which mandates that line breaking shall be
+ done before reordering each screen line separately. However,
+ following UAX#9 to the letter in this matter goes against the basic
+ design of the Emacs display engine, and so we choose here this
+ minor deviation from the UBA letter in preference to redesign of
+ the display engine. The effect of this is only seen in continued
+ lines that are broken into screen lines in the middle of a run
+ whose direction is opposite to the paragraph's base direction.
+
+ Important design and implementation note: when the code needs to
+ scan far ahead, be sure to avoid such scans as much as possible
+ when the buffer/string doesn't contain any RTL characters. Users
+ of left-to-right scripts will never forgive you if you introduce
+ some slow-down due to bidi in situations that don't involve any
+ bidirectional text. See the large comment near the beginning of
+ bidi_resolve_neutral, for one situation where such shortcut was
+ necessary. */
#include <config.h>
#include <stdio.h>
static bool bidi_initialized = 0;
-static Lisp_Object bidi_type_table, bidi_mirror_table;
+static Lisp_Object bidi_type_table, bidi_mirror_table, bidi_brackets_table;
#define BIDI_EOB (-1)
EXPLICIT_FORMATTING
} bidi_category_t;
-/* UAX#9 says to search only for L, AL, or R types of characters, and
- ignore RLE, RLO, LRE, and LRO, when determining the base paragraph
- level. Yudit indeed ignores them. This variable is therefore set
- by default to ignore them, but clearing it will take them into
- account. */
-extern bool bidi_ignore_explicit_marks_for_paragraph_level EXTERNALLY_VISIBLE;
-bool bidi_ignore_explicit_marks_for_paragraph_level = 1;
-
static Lisp_Object paragraph_start_re, paragraph_separate_re;
-static Lisp_Object Qparagraph_start, Qparagraph_separate;
\f
/***********************************************************************
case RLE:
case RLO:
case PDF:
- return default_type;
- /* FIXME: The isolate controls are treated as BN until we add
- support for UBA v6.3. */
case LRI:
case RLI:
case FSI:
case PDI:
- return WEAK_BN;
+ return default_type;
default:
if (override == L2R)
return STRONG_L;
case WEAK_CS:
case WEAK_NSM:
case WEAK_BN:
- /* FIXME */
- case LRI:
- case RLI:
- case FSI:
- case PDI:
return WEAK;
case NEUTRAL_B:
case NEUTRAL_S:
case RLE:
case RLO:
case PDF:
-#if 0
- /* FIXME: This awaits implementation of isolate support. */
case LRI:
case RLI:
case FSI:
case PDI:
-#endif
return EXPLICIT_FORMATTING;
default:
emacs_abort ();
}
}
+static bool
+bidi_isolate_fmt_char (bidi_type_t ch_type)
+{
+ return (ch_type == LRI || ch_type == RLI || ch_type == PDI || ch_type == FSI);
+}
+
/* Return the mirrored character of C, if it has one. If C has no
mirrored counterpart, return C.
Note: The conditions in UAX#9 clause L4 regarding the surrounding
return c;
}
-/* Determine the start-of-run (sor) directional type given the two
+/* Return the Bidi_Paired_Bracket_Type property of the character C. */
+static bidi_bracket_type_t
+bidi_paired_bracket_type (int c)
+{
+ if (c == BIDI_EOB)
+ return BIDI_BRACKET_NONE;
+ if (c < 0 || c > MAX_CHAR)
+ emacs_abort ();
+
+ return (bidi_bracket_type_t) XINT (CHAR_TABLE_REF (bidi_brackets_table, c));
+}
+
+/* Determine the start-of-sequence (sos) directional type given the two
embedding levels on either side of the run boundary. Also, update
the saved info about previously seen characters, since that info is
generally valid for a single level run. */
static void
-bidi_set_sor_type (struct bidi_it *bidi_it, int level_before, int level_after)
+bidi_set_sos_type (struct bidi_it *bidi_it, int level_before, int level_after)
{
int higher_level = (level_before > level_after ? level_before : level_after);
- /* The prev_was_pdf gork is required for when we have several PDFs
- in a row. In that case, we want to compute the sor type for the
- next level run only once: when we see the first PDF. That's
- because the sor type depends only on the higher of the two levels
- that we find on the two sides of the level boundary (see UAX#9,
- clause X10), and so we don't need to know the final embedding
- level to which we descend after processing all the PDFs. */
- if (!bidi_it->prev_was_pdf || level_before < level_after)
- /* FIXME: should the default sor direction be user selectable? */
- bidi_it->sor = ((higher_level & 1) != 0 ? R2L : L2R);
- if (level_before > level_after)
- bidi_it->prev_was_pdf = 1;
+ /* FIXME: should the default sos direction be user selectable? */
+ bidi_it->sos = ((higher_level & 1) != 0 ? R2L : L2R); /* X10 */
bidi_it->prev.type = UNKNOWN_BT;
- bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1
- = bidi_it->last_strong.orig_type = UNKNOWN_BT;
- bidi_it->prev_for_neutral.type = (bidi_it->sor == R2L ? STRONG_R : STRONG_L);
+ bidi_it->last_strong.type = bidi_it->last_strong.orig_type = UNKNOWN_BT;
+ bidi_it->prev_for_neutral.type = (bidi_it->sos == R2L ? STRONG_R : STRONG_L);
bidi_it->prev_for_neutral.charpos = bidi_it->charpos;
- bidi_it->prev_for_neutral.bytepos = bidi_it->bytepos;
- bidi_it->next_for_neutral.type = bidi_it->next_for_neutral.type_after_w1
+ bidi_it->next_for_neutral.type
= bidi_it->next_for_neutral.orig_type = UNKNOWN_BT;
- bidi_it->ignore_bn_limit = -1; /* meaning it's unknown */
}
+#define ISOLATE_STATUS(BIDI_IT, IDX) ((BIDI_IT)->level_stack[IDX].flags & 1)
+#define OVERRIDE(BIDI_IT, IDX) (((BIDI_IT)->level_stack[IDX].flags >> 1) & 3)
+
/* Push the current embedding level and override status; reset the
current level to LEVEL and the current override status to OVERRIDE. */
static void
bidi_push_embedding_level (struct bidi_it *bidi_it,
- int level, bidi_dir_t override)
+ int level, bidi_dir_t override, bool isolate_status)
{
+ struct bidi_stack *st;
+ int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level;
+
bidi_it->stack_idx++;
- eassert (bidi_it->stack_idx < BIDI_MAXLEVEL);
- bidi_it->level_stack[bidi_it->stack_idx].level = level;
- bidi_it->level_stack[bidi_it->stack_idx].override = override;
+ eassert (bidi_it->stack_idx < BIDI_MAXDEPTH+2+1);
+ st = &bidi_it->level_stack[bidi_it->stack_idx];
+ eassert (level <= (1 << 7));
+ st->level = level;
+ st->flags = (((override & 3) << 1) | (isolate_status != 0));
+ if (isolate_status)
+ {
+ st->last_strong_type = bidi_it->last_strong.type;
+ st->prev_for_neutral_type = bidi_it->prev_for_neutral.type;
+ st->next_for_neutral_type = bidi_it->next_for_neutral.type;
+ st->next_for_neutral_pos = bidi_it->next_for_neutral.charpos;
+ st->flags |= ((bidi_it->sos == L2R ? 0 : 1) << 3);
+ }
+ /* We've got a new isolating sequence, compute the directional type
+ of sos and initialize per-sequence variables (UAX#9, clause X10). */
+ bidi_set_sos_type (bidi_it, prev_level, level);
}
-/* Pop the embedding level and directional override status from the
- stack, and return the new level. */
+/* Pop from the stack the embedding level, the directional override
+ status, and optionally saved information for the isolating run
+ sequence. Return the new level. */
static int
bidi_pop_embedding_level (struct bidi_it *bidi_it)
{
- /* UAX#9 says to ignore invalid PDFs. */
+ int level;
+
+ /* UAX#9 says to ignore invalid PDFs (X7, last bullet)
+ and PDIs (X6a, 2nd bullet). */
if (bidi_it->stack_idx > 0)
- bidi_it->stack_idx--;
- return bidi_it->level_stack[bidi_it->stack_idx].level;
+ {
+ bool isolate_status = ISOLATE_STATUS (bidi_it, bidi_it->stack_idx);
+ int old_level = bidi_it->level_stack[bidi_it->stack_idx].level;
+
+ struct bidi_stack st;
+
+ st = bidi_it->level_stack[bidi_it->stack_idx];
+ if (isolate_status)
+ {
+ bidi_dir_t sos = ((st.flags >> 3) & 1);
+ /* PREV is used in W1 for resolving WEAK_NSM. By the time
+ we get to an NSM, we must have gotten past at least one
+ character: the PDI that ends the isolate from which we
+ are popping here. So PREV will have been filled up by
+ the time we first use it. We initialize it here to
+ UNKNOWN_BT to be able to catch any blunders in this
+ logic. */
+ bidi_it->prev.orig_type = bidi_it->prev.type = UNKNOWN_BT;
+ bidi_it->last_strong.type = st.last_strong_type;
+ bidi_it->prev_for_neutral.type = st.prev_for_neutral_type;
+ bidi_it->next_for_neutral.type = st.next_for_neutral_type;
+ bidi_it->next_for_neutral.charpos = st.next_for_neutral_pos;
+ bidi_it->sos = (sos == 0 ? L2R : R2L);
+ }
+ else
+ bidi_set_sos_type (bidi_it, old_level,
+ bidi_it->level_stack[bidi_it->stack_idx - 1].level);
+
+ bidi_it->stack_idx--;
+ }
+ level = bidi_it->level_stack[bidi_it->stack_idx].level;
+ eassert (0 <= level && level <= BIDI_MAXDEPTH + 1);
+ return level;
}
/* Record in SAVED_INFO the information about the current character. */
static void
bidi_remember_char (struct bidi_saved_info *saved_info,
- struct bidi_it *bidi_it)
+ struct bidi_it *bidi_it, bool from_type)
{
saved_info->charpos = bidi_it->charpos;
- saved_info->bytepos = bidi_it->bytepos;
- saved_info->type = bidi_it->type;
- bidi_check_type (bidi_it->type);
- saved_info->type_after_w1 = bidi_it->type_after_w1;
- bidi_check_type (bidi_it->type_after_w1);
+ if (from_type)
+ saved_info->type = bidi_it->type;
+ else
+ saved_info->type = bidi_it->type_after_wn;
+ bidi_check_type (saved_info->type);
saved_info->orig_type = bidi_it->orig_type;
- bidi_check_type (bidi_it->orig_type);
+ bidi_check_type (saved_info->orig_type);
}
/* Copy the bidi iterator from FROM to TO. To save cycles, this only
Caching the bidi iterator states
***********************************************************************/
+/* We allocate and de-allocate the cache in chunks of this size (in
+ characters). 200 was chosen as an upper limit for reasonably-long
+ lines in a text file/buffer. */
#define BIDI_CACHE_CHUNK 200
+/* Maximum size we allow the cache to become, per iterator stack slot,
+ in units of struct bidi_it size. If we allow unlimited growth, we
+ could run out of memory for pathologically long bracketed text or
+ very long text lines that need to be reordered. This is aggravated
+ when word-wrap is in effect, since then functions display_line and
+ move_it_in_display_line_to need to keep up to 4 copies of the
+ cache.
+
+ This limitation means there can be no more than that amount of
+ contiguous RTL text on any single physical line in a LTR paragraph,
+ and similarly with contiguous LTR + numeric text in a RTL
+ paragraph. (LTR text in a LTR paragraph and RTL text in a RTL
+ paragraph are not reordered, and so don't need the cache, and
+ cannot hit this limit.) More importantly, no single line can have
+ text longer than this inside paired brackets (because bracket pairs
+ resolution uses the cache). If the limit is exceeded, the fallback
+ code will produce visual order that will be incorrect if there are
+ RTL characters in the offending line of text. */
+/* Do we need to allow customization of this limit? */
+#define BIDI_CACHE_MAX_ELTS_PER_SLOT 50000
+#if BIDI_CACHE_CHUNK >= BIDI_CACHE_MAX_ELTS_PER_SLOT
+# error BIDI_CACHE_CHUNK must be less than BIDI_CACHE_MAX_ELTS_PER_SLOT
+#endif
+static ptrdiff_t bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
static struct bidi_it *bidi_cache;
static ptrdiff_t bidi_cache_size = 0;
enum { elsz = sizeof (struct bidi_it) };
bidi_shelve_header_size
= (sizeof (bidi_cache_idx) + sizeof (bidi_cache_start_stack)
+ sizeof (bidi_cache_sp) + sizeof (bidi_cache_start)
- + sizeof (bidi_cache_last_idx))
+ + sizeof (bidi_cache_last_idx) + sizeof (bidi_cache_max_elts))
};
+/* Effectively remove the cached states beyond the Nth state from the
+ part of the cache relevant to iteration of the current object
+ (buffer or string). */
+static void
+bidi_cache_reset_to (int n)
+{
+ bidi_cache_idx = bidi_cache_start + n;
+ bidi_cache_last_idx = -1;
+}
+
/* Reset the cache state to the empty state. We only reset the part
of the cache relevant to iteration of the current object. Previous
objects, which are pushed on the display iterator's stack, are left
static void
bidi_cache_reset (void)
{
- bidi_cache_idx = bidi_cache_start;
- bidi_cache_last_idx = -1;
+ bidi_cache_reset_to (0);
}
/* Shrink the cache to its minimal size. Called when we init the bidi
bidi_cache_size = BIDI_CACHE_CHUNK;
}
bidi_cache_reset ();
+ bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
}
static void
}
/* Find a cached state with a given CHARPOS and resolved embedding
- level less or equal to LEVEL. if LEVEL is -1, disregard the
+ level less or equal to LEVEL. If LEVEL is -1, disregard the
resolved levels in cached states. DIR, if non-zero, means search
- in that direction from the last cache hit. */
+ in that direction from the last cache hit.
+
+ Value is the index of the cached state, or -1 if not found. */
static ptrdiff_t
bidi_cache_search (ptrdiff_t charpos, int level, int dir)
{
ptrdiff_t i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1;
int incr = before ? 1 : 0;
- eassert (!dir || bidi_cache_last_idx >= 0);
+ if (i < 0) /* cache overflowed? */
+ i = 0;
if (!dir)
dir = -1;
/* Enlarge the cache as needed. */
if (idx >= bidi_cache_size)
{
- /* The bidi cache cannot be larger than the largest Lisp string
- or buffer. */
- ptrdiff_t string_or_buffer_bound
- = max (BUF_BYTES_MAX, STRING_BYTES_BOUND);
+ ptrdiff_t chunk_size = BIDI_CACHE_CHUNK;
- /* Also, it cannot be larger than what C can represent. */
- ptrdiff_t c_bound
- = (min (PTRDIFF_MAX, SIZE_MAX) - bidi_shelve_header_size) / elsz;
+ if (bidi_cache_size > bidi_cache_max_elts - chunk_size)
+ chunk_size = bidi_cache_max_elts - bidi_cache_size;
- bidi_cache
- = xpalloc (bidi_cache, &bidi_cache_size,
- max (BIDI_CACHE_CHUNK, idx - bidi_cache_size + 1),
- min (string_or_buffer_bound, c_bound), elsz);
+ if (max (idx + 1,
+ bidi_cache_size + chunk_size) <= bidi_cache_max_elts)
+ {
+ /* The bidi cache cannot be larger than the largest Lisp
+ string or buffer. */
+ ptrdiff_t string_or_buffer_bound
+ = max (BUF_BYTES_MAX, STRING_BYTES_BOUND);
+
+ /* Also, it cannot be larger than what C can represent. */
+ ptrdiff_t c_bound
+ = (min (PTRDIFF_MAX, SIZE_MAX) - bidi_shelve_header_size) / elsz;
+ ptrdiff_t max_elts = bidi_cache_max_elts;
+
+ max_elts = min (max_elts, min (string_or_buffer_bound, c_bound));
+
+ /* Force xpalloc not to over-allocate by passing it MAX_ELTS
+ as its 4th argument. */
+ bidi_cache = xpalloc (bidi_cache, &bidi_cache_size,
+ max (chunk_size, idx - bidi_cache_size + 1),
+ max_elts, elsz);
+ eassert (bidi_cache_size > idx);
+ }
}
}
-static void
-bidi_cache_iterator_state (struct bidi_it *bidi_it, bool resolved)
+static int
+bidi_cache_iterator_state (struct bidi_it *bidi_it, bool resolved,
+ bool update_only)
{
ptrdiff_t idx;
emacs_abort ();
idx = bidi_cache_search (bidi_it->charpos, -1, 1);
+ if (idx < 0 && update_only)
+ return 0;
+
if (idx < 0)
{
idx = bidi_cache_idx;
/* Character positions should correspond to cache positions 1:1.
If we are outside the range of cached positions, the cache is
useless and must be reset. */
- if (idx > bidi_cache_start &&
- (bidi_it->charpos > (bidi_cache[idx - 1].charpos
- + bidi_cache[idx - 1].nchars)
- || bidi_it->charpos < bidi_cache[bidi_cache_start].charpos))
+ if (bidi_cache_start < idx && idx < bidi_cache_size
+ && (bidi_it->charpos > (bidi_cache[idx - 1].charpos
+ + bidi_cache[idx - 1].nchars)
+ || bidi_it->charpos < bidi_cache[bidi_cache_start].charpos))
{
bidi_cache_reset ();
idx = bidi_cache_start;
}
if (bidi_it->nchars <= 0)
emacs_abort ();
- bidi_copy_it (&bidi_cache[idx], bidi_it);
- if (!resolved)
- bidi_cache[idx].resolved_level = -1;
+ /* Don't cache if no available space in the cache. */
+ if (bidi_cache_size > idx)
+ {
+ bidi_copy_it (&bidi_cache[idx], bidi_it);
+ if (!resolved)
+ bidi_cache[idx].resolved_level = -1;
+ }
}
else
{
costly copying of the entire struct. */
bidi_cache[idx].type = bidi_it->type;
bidi_check_type (bidi_it->type);
- bidi_cache[idx].type_after_w1 = bidi_it->type_after_w1;
- bidi_check_type (bidi_it->type_after_w1);
+ bidi_cache[idx].type_after_wn = bidi_it->type_after_wn;
+ bidi_check_type (bidi_it->type_after_wn);
if (resolved)
bidi_cache[idx].resolved_level = bidi_it->resolved_level;
else
bidi_cache[idx].resolved_level = -1;
bidi_cache[idx].invalid_levels = bidi_it->invalid_levels;
- bidi_cache[idx].invalid_rl_levels = bidi_it->invalid_rl_levels;
bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral;
bidi_cache[idx].next_for_ws = bidi_it->next_for_ws;
- bidi_cache[idx].ignore_bn_limit = bidi_it->ignore_bn_limit;
bidi_cache[idx].disp_pos = bidi_it->disp_pos;
bidi_cache[idx].disp_prop = bidi_it->disp_prop;
+ bidi_cache[idx].bracket_pairing_pos = bidi_it->bracket_pairing_pos;
+ bidi_cache[idx].bracket_enclosed_type = bidi_it->bracket_enclosed_type;
}
- bidi_cache_last_idx = idx;
- if (idx >= bidi_cache_idx)
- bidi_cache_idx = idx + 1;
+ if (bidi_cache_size > idx)
+ {
+ bidi_cache_last_idx = idx;
+ if (idx >= bidi_cache_idx)
+ bidi_cache_idx = idx + 1;
+ return 1;
+ }
+ else
+ {
+ /* The cache overflowed. */
+ bidi_cache_last_idx = -1;
+ return 0;
+ }
}
+/* Look for a cached iterator state that corresponds to CHARPOS. If
+ found, copy the cached state into BIDI_IT and return the type of
+ the cached entry. If not found, return UNKNOWN_BT. RESOLVED_ONLY
+ zero means it is OK to return cached states that were not fully
+ resolved yet. This can happen if the state was cached before it
+ was resolved in bidi_resolve_neutral. */
static bidi_type_t
-bidi_cache_find (ptrdiff_t charpos, int level, struct bidi_it *bidi_it)
+bidi_cache_find (ptrdiff_t charpos, bool resolved_only, struct bidi_it *bidi_it)
{
- ptrdiff_t i = bidi_cache_search (charpos, level, bidi_it->scan_dir);
-
- if (i >= bidi_cache_start)
+ ptrdiff_t i = bidi_cache_search (charpos, -1, bidi_it->scan_dir);
+
+ if (i >= bidi_cache_start
+ && (!resolved_only
+ /* Callers that want only fully resolved states (and set
+ resolved_only = true) need to be sure that there's enough
+ info in the cached state to return the state as final,
+ and if not, they don't want the cached state. */
+ || bidi_cache[i].resolved_level >= 0))
{
bidi_dir_t current_scan_dir = bidi_it->scan_dir;
static int
bidi_peek_at_next_level (struct bidi_it *bidi_it)
{
- if (bidi_cache_idx == bidi_cache_start || bidi_cache_last_idx == -1)
+ if (bidi_cache_idx == bidi_cache_start)
emacs_abort ();
+ /* If the cache overflowed, return the level of the last cached
+ character. */
+ if (bidi_cache_last_idx == -1
+ || (bidi_cache_last_idx >= bidi_cache_idx - 1 && bidi_it->scan_dir > 0))
+ return bidi_cache[bidi_cache_idx - 1].resolved_level;
return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level;
}
void
bidi_push_it (struct bidi_it *bidi_it)
{
+ /* Give this stack slot its cache room. */
+ bidi_cache_max_elts += BIDI_CACHE_MAX_ELTS_PER_SLOT;
/* Save the current iterator state in its entirety after the last
used cache slot. */
bidi_cache_ensure_space (bidi_cache_idx);
/* Invalidate the last-used cache slot data. */
bidi_cache_last_idx = -1;
+
+ bidi_cache_max_elts -= BIDI_CACHE_MAX_ELTS_PER_SLOT;
+ eassert (bidi_cache_max_elts > 0);
}
static ptrdiff_t bidi_cache_total_alloc;
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ sizeof (bidi_cache_start),
&bidi_cache_last_idx, sizeof (bidi_cache_last_idx));
+ memcpy (databuf + sizeof (bidi_cache_idx)
+ + bidi_cache_idx * sizeof (struct bidi_it)
+ + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ + sizeof (bidi_cache_start) + sizeof (bidi_cache_last_idx),
+ &bidi_cache_max_elts, sizeof (bidi_cache_max_elts));
return databuf;
}
/* A NULL pointer means an empty cache. */
bidi_cache_start = 0;
bidi_cache_sp = 0;
+ bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
bidi_cache_reset ();
}
}
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ sizeof (bidi_cache_start),
sizeof (bidi_cache_last_idx));
+ memcpy (&bidi_cache_max_elts,
+ p + sizeof (bidi_cache_idx)
+ + bidi_cache_idx * sizeof (struct bidi_it)
+ + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ + sizeof (bidi_cache_start) + sizeof (bidi_cache_last_idx),
+ sizeof (bidi_cache_max_elts));
bidi_cache_total_alloc
-= (bidi_shelve_header_size
+ bidi_cache_idx * sizeof (struct bidi_it));
emacs_abort ();
staticpro (&bidi_mirror_table);
- Qparagraph_start = intern ("paragraph-start");
- staticpro (&Qparagraph_start);
+ bidi_brackets_table = uniprop_table (intern ("bracket-type"));
+ if (NILP (bidi_brackets_table))
+ emacs_abort ();
+ staticpro (&bidi_brackets_table);
+
+ DEFSYM (Qparagraph_start, "paragraph-start");
paragraph_start_re = Fsymbol_value (Qparagraph_start);
if (!STRINGP (paragraph_start_re))
paragraph_start_re = build_string ("\f\\|[ \t]*$");
staticpro (¶graph_start_re);
- Qparagraph_separate = intern ("paragraph-separate");
- staticpro (&Qparagraph_separate);
+ DEFSYM (Qparagraph_separate, "paragraph-separate");
paragraph_separate_re = Fsymbol_value (Qparagraph_separate);
if (!STRINGP (paragraph_separate_re))
paragraph_separate_re = build_string ("[ \t\f]*$");
bidi_cache_sp = 0;
bidi_cache_total_alloc = 0;
+ bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
bidi_initialized = 1;
}
bidi_set_paragraph_end (struct bidi_it *bidi_it)
{
bidi_it->invalid_levels = 0;
- bidi_it->invalid_rl_levels = -1;
+ bidi_it->invalid_isolates = 0;
bidi_it->stack_idx = 0;
bidi_it->resolved_level = bidi_it->level_stack[0].level;
}
if (bytepos >= 0)
bidi_it->bytepos = bytepos;
bidi_it->frame_window_p = frame_window_p;
- bidi_it->nchars = -1; /* to be computed in bidi_resolve_explicit_1 */
+ bidi_it->nchars = -1; /* to be computed in bidi_resolve_explicit */
bidi_it->first_elt = 1;
bidi_set_paragraph_end (bidi_it);
bidi_it->new_paragraph = 1;
bidi_it->separator_limit = -1;
bidi_it->type = NEUTRAL_B;
- bidi_it->type_after_w1 = NEUTRAL_B;
+ bidi_it->type_after_wn = NEUTRAL_B;
bidi_it->orig_type = NEUTRAL_B;
- bidi_it->prev_was_pdf = 0;
- bidi_it->prev.type = bidi_it->prev.type_after_w1
- = bidi_it->prev.orig_type = UNKNOWN_BT;
- bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1
- = bidi_it->last_strong.orig_type = UNKNOWN_BT;
+ /* FIXME: Review this!!! */
+ bidi_it->prev.type = bidi_it->prev.orig_type = UNKNOWN_BT;
+ bidi_it->last_strong.type = bidi_it->last_strong.orig_type = UNKNOWN_BT;
bidi_it->next_for_neutral.charpos = -1;
bidi_it->next_for_neutral.type
- = bidi_it->next_for_neutral.type_after_w1
= bidi_it->next_for_neutral.orig_type = UNKNOWN_BT;
bidi_it->prev_for_neutral.charpos = -1;
bidi_it->prev_for_neutral.type
- = bidi_it->prev_for_neutral.type_after_w1
= bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT;
- bidi_it->sor = L2R; /* FIXME: should it be user-selectable? */
+ bidi_it->bracket_pairing_pos = -1;
+ bidi_it->sos = L2R; /* FIXME: should it be user-selectable? */
bidi_it->disp_pos = -1; /* invalid/unknown */
bidi_it->disp_prop = 0;
/* We can only shrink the cache if we are at the bottom level of its
bidi_line_init (struct bidi_it *bidi_it)
{
bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */
+ bidi_it->stack_idx = 0;
bidi_it->resolved_level = bidi_it->level_stack[0].level;
- bidi_it->level_stack[0].override = NEUTRAL_DIR; /* X1 */
+ bidi_it->level_stack[0].flags = 0; /* NEUTRAL_DIR, false per X1 */
bidi_it->invalid_levels = 0;
- bidi_it->invalid_rl_levels = -1;
+ bidi_it->isolate_level = 0; /* X1 */
+ bidi_it->invalid_isolates = 0; /* X1 */
/* Setting this to zero will force its recomputation the first time
we need it for W5. */
bidi_it->next_en_pos = 0;
bidi_it->next_en_type = UNKNOWN_BT;
+ bidi_it->next_for_ws.charpos = -1;
bidi_it->next_for_ws.type = UNKNOWN_BT;
- bidi_set_sor_type (bidi_it,
+ bidi_it->bracket_pairing_pos = -1;
+ bidi_set_sos_type (bidi_it,
(bidi_it->paragraph_dir == R2L ? 1 : 0),
bidi_it->level_stack[0].level); /* X10 */
return ch;
}
+/* Like bidi_fetch_char, but ignore any text between an isolate
+ initiator and its matching PDI or, if it has no matching PDI, the
+ end of the paragraph. If isolates were skipped, CH_LEN and NCHARS
+ are set to the number of bytes and characters between BYTEPOS/CHARPOS
+ and the character that was fetched after skipping the isolates. */
+static int
+bidi_fetch_char_skip_isolates (ptrdiff_t charpos, ptrdiff_t bytepos,
+ ptrdiff_t *disp_pos, int *disp_prop,
+ struct bidi_string_data *string,
+ struct window *w, bool frame_window_p,
+ ptrdiff_t *ch_len, ptrdiff_t *nchars)
+{
+ ptrdiff_t orig_charpos = charpos, orig_bytepos = bytepos;
+ int ch = bidi_fetch_char (charpos, bytepos, disp_pos, disp_prop, string, w,
+ frame_window_p, ch_len, nchars);
+ bidi_type_t ch_type = bidi_get_type (ch, NEUTRAL_DIR);
+ ptrdiff_t level = 0;
+
+ if (ch_type == LRI || ch_type == RLI || ch_type == FSI)
+ {
+ level++;
+ while (level > 0 && ch_type != NEUTRAL_B)
+ {
+ charpos += *nchars;
+ bytepos += *ch_len;
+ ch = bidi_fetch_char (charpos, bytepos, disp_pos, disp_prop, string,
+ w, frame_window_p, ch_len, nchars);
+ ch_type = bidi_get_type (ch, NEUTRAL_DIR);
+ /* A Note to P2 says to ignore max_depth limit. */
+ if (ch_type == LRI || ch_type == RLI || ch_type == FSI)
+ level++;
+ else if (ch_type == PDI)
+ level--;
+ }
+ }
+
+ /* Communicate to the caller how much did we skip, so it could get
+ past the last character position we examined. */
+ *nchars += charpos - orig_charpos;
+ *ch_len += bytepos - orig_bytepos;
+ return ch;
+}
+
+
\f
/***********************************************************************
Determining paragraph direction
bidi_paragraph_init to less than 10 ms even on slow machines. */
#define MAX_STRONG_CHAR_SEARCH 100000
+/* Starting from POS, find the first strong (L, R, or AL) character,
+ while skipping over any characters between an isolate initiator and
+ its matching PDI. STOP_AT_PDI non-zero means stop at the PDI that
+ matches the isolate initiator at POS. Return the bidi type of the
+ character where the search stopped. Give up if after examining
+ MAX_STRONG_CHAR_SEARCH buffer or string positions no strong
+ character was found. */
+static bidi_type_t
+find_first_strong_char (ptrdiff_t pos, ptrdiff_t bytepos, ptrdiff_t end,
+ ptrdiff_t *disp_pos, int *disp_prop,
+ struct bidi_string_data *string, struct window *w,
+ bool string_p, bool frame_window_p,
+ ptrdiff_t *ch_len, ptrdiff_t *nchars, bool stop_at_pdi)
+{
+ ptrdiff_t pos1;
+ bidi_type_t type;
+ int ch;
+
+ if (stop_at_pdi)
+ {
+ /* If STOP_AT_PDI is non-zero, we must have been called with FSI
+ at POS. Get past it. */
+#ifdef ENABLE_CHECKING
+ ch = bidi_fetch_char (pos, bytepos, disp_pos, disp_prop, string, w,
+ frame_window_p, ch_len, nchars);
+ type = bidi_get_type (ch, NEUTRAL_DIR);
+ eassert (type == FSI /* || type == LRI || type == RLI */);
+#endif
+ pos += *nchars;
+ bytepos += *ch_len;
+ }
+ ch = bidi_fetch_char_skip_isolates (pos, bytepos, disp_pos, disp_prop, string,
+ w, frame_window_p, ch_len, nchars);
+ type = bidi_get_type (ch, NEUTRAL_DIR);
+
+ pos1 = pos;
+ for (pos += *nchars, bytepos += *ch_len;
+ bidi_get_category (type) != STRONG
+ /* If requested to stop at first PDI, stop there. */
+ && !(stop_at_pdi && type == PDI)
+ /* Stop when searched too far into an abnormally large
+ paragraph full of weak or neutral characters. */
+ && pos - pos1 < MAX_STRONG_CHAR_SEARCH;
+ type = bidi_get_type (ch, NEUTRAL_DIR))
+ {
+ if (pos >= end)
+ {
+ /* Pretend there's a paragraph separator at end of
+ buffer/string. */
+ type = NEUTRAL_B;
+ break;
+ }
+ if (!string_p
+ && type == NEUTRAL_B
+ && bidi_at_paragraph_end (pos, bytepos) >= -1)
+ break;
+ /* Fetch next character and advance to get past it. */
+ ch = bidi_fetch_char_skip_isolates (pos, bytepos, disp_pos, disp_prop,
+ string, w, frame_window_p,
+ ch_len, nchars);
+ pos += *nchars;
+ bytepos += *ch_len;
+ }
+ return type;
+}
+
/* Determine the base direction, a.k.a. base embedding level, of the
paragraph we are about to iterate through. If DIR is either L2R or
R2L, just use that. Otherwise, determine the paragraph direction
}
else if (dir == NEUTRAL_DIR) /* P2 */
{
- int ch;
ptrdiff_t ch_len, nchars;
ptrdiff_t pos, disp_pos = -1;
int disp_prop = 0;
/* The following loop is run more than once only if NO_DEFAULT_P,
and only if we are iterating on a buffer. */
do {
- ptrdiff_t pos1;
-
bytepos = pstartbyte;
if (!string_p)
pos = BYTE_TO_CHAR (bytepos);
- ch = bidi_fetch_char (pos, bytepos, &disp_pos, &disp_prop,
- &bidi_it->string, bidi_it->w,
- bidi_it->frame_window_p, &ch_len, &nchars);
- type = bidi_get_type (ch, NEUTRAL_DIR);
-
- pos1 = pos;
- for (pos += nchars, bytepos += ch_len;
- ((bidi_get_category (type) != STRONG)
- || (bidi_ignore_explicit_marks_for_paragraph_level
- && (type == RLE || type == RLO
- || type == LRE || type == LRO)))
- /* Stop when searched too far into an abnormally large
- paragraph full of weak or neutral characters. */
- && pos - pos1 < MAX_STRONG_CHAR_SEARCH;
- type = bidi_get_type (ch, NEUTRAL_DIR))
- {
- if (pos >= end)
- {
- /* Pretend there's a paragraph separator at end of
- buffer/string. */
- type = NEUTRAL_B;
- break;
- }
- if (!string_p
- && type == NEUTRAL_B
- && bidi_at_paragraph_end (pos, bytepos) >= -1)
- break;
- /* Fetch next character and advance to get past it. */
- ch = bidi_fetch_char (pos, bytepos, &disp_pos,
- &disp_prop, &bidi_it->string, bidi_it->w,
- bidi_it->frame_window_p, &ch_len, &nchars);
- pos += nchars;
- bytepos += ch_len;
- }
- if ((type == STRONG_R || type == STRONG_AL) /* P3 */
- || (!bidi_ignore_explicit_marks_for_paragraph_level
- && (type == RLO || type == RLE)))
+ type = find_first_strong_char (pos, bytepos, end, &disp_pos, &disp_prop,
+ &bidi_it->string, bidi_it->w,
+ string_p, bidi_it->frame_window_p,
+ &ch_len, &nchars, false);
+ if (type == STRONG_R || type == STRONG_AL) /* P3 */
bidi_it->paragraph_dir = R2L;
- else if (type == STRONG_L
- || (!bidi_ignore_explicit_marks_for_paragraph_level
- && (type == LRO || type == LRE)))
+ else if (type == STRONG_L)
bidi_it->paragraph_dir = L2R;
if (!string_p
&& no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR)
|| ch_type == PDF);
}
-/* A helper function for bidi_resolve_explicit. It advances to the
- next character in logical order and determines the new embedding
- level and directional override, but does not take into account
- empty embeddings. */
+/* Given an iterator state in BIDI_IT, advance one character position
+ in the buffer/string to the next character (in the logical order),
+ resolve any explicit embeddings, directional overrides, and isolate
+ initiators and terminators, and return the embedding level of the
+ character after resolving these explicit directives. */
static int
-bidi_resolve_explicit_1 (struct bidi_it *bidi_it)
+bidi_resolve_explicit (struct bidi_it *bidi_it)
{
int curchar;
- bidi_type_t type;
+ bidi_type_t type, typ1, prev_type = UNKNOWN_BT;
int current_level;
int new_level;
bidi_dir_t override;
+ bool isolate_status;
bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring);
+ ptrdiff_t ch_len, nchars, disp_pos, end;
+ int disp_prop;
+ ptrdiff_t eob
+ = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
+ ? bidi_it->string.schars : ZV);
+
+ /* Record the info about the previous character. */
+ if (bidi_it->type_after_wn != WEAK_BN /* W1/Retaining */
+ && bidi_it->type != WEAK_BN)
+ {
+ /* This special case is needed in support of Unicode 8.0
+ correction to N0, as implemented in bidi_resolve_weak/W1
+ below. */
+ if (bidi_it->type_after_wn == NEUTRAL_ON
+ && bidi_get_category (bidi_it->type) == STRONG
+ && bidi_paired_bracket_type (bidi_it->ch) == BIDI_BRACKET_CLOSE)
+ bidi_remember_char (&bidi_it->prev, bidi_it, 1);
+ else
+ bidi_remember_char (&bidi_it->prev, bidi_it, 0);
+ }
+ if (bidi_it->type_after_wn == STRONG_R
+ || bidi_it->type_after_wn == STRONG_L
+ || bidi_it->type_after_wn == STRONG_AL)
+ bidi_remember_char (&bidi_it->last_strong, bidi_it, 0);
+ if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L
+ || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN)
+ bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it, 1);
+
+ /* If we overstepped the characters used for resolving neutrals
+ and whitespace, invalidate their info in the iterator. */
+ if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos)
+ {
+ bidi_it->next_for_neutral.type = UNKNOWN_BT;
+ /* If needed, reset the "magical" value of pairing bracket
+ position, so that bidi_resolve_brackets will resume
+ resolution of brackets according to BPA. */
+ if (bidi_it->bracket_pairing_pos == eob)
+ bidi_it->bracket_pairing_pos = -1;
+ }
+ if (bidi_it->next_en_pos >= 0
+ && bidi_it->charpos >= bidi_it->next_en_pos)
+ {
+ bidi_it->next_en_pos = 0;
+ bidi_it->next_en_type = UNKNOWN_BT;
+ }
+
+ /* Reset the bracket resolution info, unless we previously decided
+ (in bidi_find_bracket_pairs) that brackets in this level run
+ should be resolved as neutrals. */
+ if (bidi_it->bracket_pairing_pos != eob)
+ {
+ bidi_it->bracket_pairing_pos = -1;
+ bidi_it->bracket_enclosed_type = UNKNOWN_BT;
+ }
/* If reseat()'ed, don't advance, so as to start iteration from the
position where we were reseated. bidi_it->bytepos can be less
}
eassert (bidi_it->bytepos == CHAR_TO_BYTE (bidi_it->charpos));
}
+ /* Determine the original bidi type of the previous character,
+ which is needed for handling isolate initiators and PDF. The
+ type of the previous character will be non-trivial only if
+ our caller moved through some previous text in
+ get_visually_first_element, in which case bidi_it->prev holds
+ the information we want. */
+ if (bidi_it->first_elt && bidi_it->prev.type != UNKNOWN_BT)
+ {
+ eassert (bidi_it->prev.charpos == bidi_it->charpos - 1);
+ prev_type = bidi_it->prev.orig_type;
+ if (prev_type == FSI)
+ prev_type = bidi_it->type_after_wn;
+ }
}
/* Don't move at end of buffer/string. */
else if (bidi_it->charpos < (string_p ? bidi_it->string.schars : ZV))
if (bidi_it->ch_len == 0)
emacs_abort ();
bidi_it->bytepos += bidi_it->ch_len;
+ prev_type = bidi_it->orig_type;
+ if (prev_type == FSI)
+ prev_type = bidi_it->type_after_wn;
}
+ else /* EOB or end of string */
+ prev_type = NEUTRAL_B;
current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */
- override = bidi_it->level_stack[bidi_it->stack_idx].override;
+ isolate_status = ISOLATE_STATUS (bidi_it, bidi_it->stack_idx);
+ override = OVERRIDE (bidi_it, bidi_it->stack_idx);
new_level = current_level;
if (bidi_it->charpos >= (string_p ? bidi_it->string.schars : ZV))
}
else
{
+ /* LRI, RLI, and FSI increment, and PDF decrements, the
+ embedding level of the _following_ characters, so we must
+ first look at the type of the previous character to support
+ that. */
+ switch (prev_type)
+ {
+ case RLI: /* X5a */
+ if (current_level < BIDI_MAXDEPTH
+ && bidi_it->invalid_levels == 0
+ && bidi_it->invalid_isolates == 0)
+ {
+ new_level = ((current_level + 1) & ~1) + 1;
+ bidi_it->isolate_level++;
+ bidi_push_embedding_level (bidi_it, new_level,
+ NEUTRAL_DIR, true);
+ }
+ else
+ bidi_it->invalid_isolates++;
+ break;
+ case LRI: /* X5b */
+ if (current_level < BIDI_MAXDEPTH - 1
+ && bidi_it->invalid_levels == 0
+ && bidi_it->invalid_isolates == 0)
+ {
+ new_level = ((current_level + 2) & ~1);
+ bidi_it->isolate_level++;
+ bidi_push_embedding_level (bidi_it, new_level,
+ NEUTRAL_DIR, true);
+ }
+ else
+ bidi_it->invalid_isolates++;
+ break;
+ case PDF: /* X7 */
+ if (!bidi_it->invalid_isolates)
+ {
+ if (bidi_it->invalid_levels)
+ bidi_it->invalid_levels--;
+ else if (!isolate_status && bidi_it->stack_idx >= 1)
+ new_level = bidi_pop_embedding_level (bidi_it);
+ }
+ break;
+ default:
+ eassert (prev_type != FSI);
+ /* Nothing. */
+ break;
+ }
/* Fetch the character at BYTEPOS. If it is covered by a
display string, treat the entire run of covered characters as
a single character u+FFFC. */
&bidi_it->ch_len, &bidi_it->nchars);
}
bidi_it->ch = curchar;
+ bidi_it->resolved_level = new_level;
/* Don't apply directional override here, as all the types we handle
below will not be affected by the override anyway, and we need
bidi_it->orig_type = type;
bidi_check_type (bidi_it->orig_type);
- if (type != PDF)
- bidi_it->prev_was_pdf = 0;
-
- bidi_it->type_after_w1 = UNKNOWN_BT;
+ bidi_it->type_after_wn = UNKNOWN_BT;
switch (type)
{
- case RLE: /* X2 */
- case RLO: /* X4 */
- bidi_it->type_after_w1 = type;
- bidi_check_type (bidi_it->type_after_w1);
- type = WEAK_BN; /* X9/Retaining */
- if (bidi_it->ignore_bn_limit <= -1)
- {
- if (current_level <= BIDI_MAXLEVEL - 4)
- {
- /* Compute the least odd embedding level greater than
- the current level. */
- new_level = ((current_level + 1) & ~1) + 1;
- if (bidi_it->type_after_w1 == RLE)
- override = NEUTRAL_DIR;
- else
- override = R2L;
- if (current_level == BIDI_MAXLEVEL - 4)
- bidi_it->invalid_rl_levels = 0;
- bidi_push_embedding_level (bidi_it, new_level, override);
- }
- else
- {
- bidi_it->invalid_levels++;
- /* See the commentary about invalid_rl_levels below. */
- if (bidi_it->invalid_rl_levels < 0)
- bidi_it->invalid_rl_levels = 0;
- bidi_it->invalid_rl_levels++;
- }
- }
- else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */
- || (bidi_it->next_en_pos > bidi_it->charpos
- && bidi_it->next_en_type == WEAK_EN))
- type = WEAK_EN;
- break;
- case LRE: /* X3 */
- case LRO: /* X5 */
- bidi_it->type_after_w1 = type;
- bidi_check_type (bidi_it->type_after_w1);
- type = WEAK_BN; /* X9/Retaining */
- if (bidi_it->ignore_bn_limit <= -1)
- {
- if (current_level <= BIDI_MAXLEVEL - 5)
- {
- /* Compute the least even embedding level greater than
- the current level. */
- new_level = ((current_level + 2) & ~1);
- if (bidi_it->type_after_w1 == LRE)
- override = NEUTRAL_DIR;
- else
- override = L2R;
- bidi_push_embedding_level (bidi_it, new_level, override);
- }
- else
- {
- bidi_it->invalid_levels++;
- /* invalid_rl_levels counts invalid levels encountered
- while the embedding level was already too high for
- LRE/LRO, but not for RLE/RLO. That is because
- there may be exactly one PDF which we should not
- ignore even though invalid_levels is non-zero.
- invalid_rl_levels helps to know what PDF is
- that. */
- if (bidi_it->invalid_rl_levels >= 0)
- bidi_it->invalid_rl_levels++;
- }
- }
- else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */
- || (bidi_it->next_en_pos > bidi_it->charpos
- && bidi_it->next_en_type == WEAK_EN))
- type = WEAK_EN;
- break;
- case PDF: /* X7 */
- bidi_it->type_after_w1 = type;
- bidi_check_type (bidi_it->type_after_w1);
- type = WEAK_BN; /* X9/Retaining */
- if (bidi_it->ignore_bn_limit <= -1)
- {
- if (!bidi_it->invalid_rl_levels)
- {
- new_level = bidi_pop_embedding_level (bidi_it);
- bidi_it->invalid_rl_levels = -1;
- if (bidi_it->invalid_levels)
- bidi_it->invalid_levels--;
- /* else nothing: UAX#9 says to ignore invalid PDFs */
- }
- if (!bidi_it->invalid_levels)
- new_level = bidi_pop_embedding_level (bidi_it);
- else
- {
- bidi_it->invalid_levels--;
- bidi_it->invalid_rl_levels--;
- }
- }
- else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */
- || (bidi_it->next_en_pos > bidi_it->charpos
- && bidi_it->next_en_type == WEAK_EN))
- type = WEAK_EN;
- break;
- default:
- /* Nothing. */
- break;
- }
-
- bidi_it->type = type;
- bidi_check_type (bidi_it->type);
-
- return new_level;
-}
-
-/* Given an iterator state in BIDI_IT, advance one character position
- in the buffer/string to the next character (in the logical order),
- resolve any explicit embeddings and directional overrides, and
- return the embedding level of the character after resolving
- explicit directives and ignoring empty embeddings. */
-static int
-bidi_resolve_explicit (struct bidi_it *bidi_it)
-{
- int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level;
- int new_level = bidi_resolve_explicit_1 (bidi_it);
- ptrdiff_t eob = bidi_it->string.s ? bidi_it->string.schars : ZV;
- const unsigned char *s
- = (STRINGP (bidi_it->string.lstring)
- ? SDATA (bidi_it->string.lstring)
- : bidi_it->string.s);
-
- if (prev_level < new_level
- && bidi_it->type == WEAK_BN
- && bidi_it->ignore_bn_limit == -1 /* only if not already known */
- && bidi_it->charpos < eob /* not already at EOB */
- && bidi_explicit_dir_char (bidi_char_at_pos (bidi_it->bytepos
- + bidi_it->ch_len, s,
- bidi_it->string.unibyte)))
- {
- /* Avoid pushing and popping embedding levels if the level run
- is empty, as this breaks level runs where it shouldn't.
- UAX#9 removes all the explicit embedding and override codes,
- so empty embeddings disappear without a trace. We need to
- behave as if we did the same. */
- struct bidi_it saved_it;
- int level = prev_level;
-
- bidi_copy_it (&saved_it, bidi_it);
-
- while (bidi_explicit_dir_char (bidi_char_at_pos (bidi_it->bytepos
- + bidi_it->ch_len, s,
- bidi_it->string.unibyte)))
+ case RLE: /* X2 */
+ case RLO: /* X4 */
+ bidi_it->type_after_wn = type;
+ bidi_check_type (bidi_it->type_after_wn);
+ type = WEAK_BN; /* X9/Retaining */
+ if (new_level < BIDI_MAXDEPTH
+ && bidi_it->invalid_levels == 0
+ && bidi_it->invalid_isolates == 0)
{
- /* This advances to the next character, skipping any
- characters covered by display strings. */
- level = bidi_resolve_explicit_1 (bidi_it);
- /* If string.lstring was relocated inside bidi_resolve_explicit_1,
- a pointer to its data is no longer valid. */
- if (STRINGP (bidi_it->string.lstring))
- s = SDATA (bidi_it->string.lstring);
+ /* Compute the least odd embedding level greater than
+ the current level. */
+ new_level = ((new_level + 1) & ~1) + 1;
+ if (bidi_it->type_after_wn == RLE)
+ override = NEUTRAL_DIR;
+ else
+ override = R2L;
+ bidi_push_embedding_level (bidi_it, new_level, override, false);
+ bidi_it->resolved_level = new_level;
}
-
- if (bidi_it->nchars <= 0)
- emacs_abort ();
- if (level == prev_level) /* empty embedding */
- saved_it.ignore_bn_limit = bidi_it->charpos + bidi_it->nchars;
- else /* this embedding is non-empty */
- saved_it.ignore_bn_limit = -2;
-
- bidi_copy_it (bidi_it, &saved_it);
- if (bidi_it->ignore_bn_limit > -1)
+ else
{
- /* We pushed a level, but we shouldn't have. Undo that. */
- if (!bidi_it->invalid_rl_levels)
- {
- new_level = bidi_pop_embedding_level (bidi_it);
- bidi_it->invalid_rl_levels = -1;
- if (bidi_it->invalid_levels)
- bidi_it->invalid_levels--;
- }
- if (!bidi_it->invalid_levels)
- new_level = bidi_pop_embedding_level (bidi_it);
+ if (bidi_it->invalid_isolates == 0)
+ bidi_it->invalid_levels++;
+ }
+ break;
+ case LRE: /* X3 */
+ case LRO: /* X5 */
+ bidi_it->type_after_wn = type;
+ bidi_check_type (bidi_it->type_after_wn);
+ type = WEAK_BN; /* X9/Retaining */
+ if (new_level < BIDI_MAXDEPTH - 1
+ && bidi_it->invalid_levels == 0
+ && bidi_it->invalid_isolates == 0)
+ {
+ /* Compute the least even embedding level greater than
+ the current level. */
+ new_level = ((new_level + 2) & ~1);
+ if (bidi_it->type_after_wn == LRE)
+ override = NEUTRAL_DIR;
else
- {
- bidi_it->invalid_levels--;
- bidi_it->invalid_rl_levels--;
- }
+ override = L2R;
+ bidi_push_embedding_level (bidi_it, new_level, override, false);
+ bidi_it->resolved_level = new_level;
}
+ else
+ {
+ if (bidi_it->invalid_isolates == 0)
+ bidi_it->invalid_levels++;
+ }
+ break;
+ case FSI: /* X5c */
+ end = string_p ? bidi_it->string.schars : ZV;
+ disp_pos = bidi_it->disp_pos;
+ disp_prop = bidi_it->disp_prop;
+ nchars = bidi_it->nchars;
+ ch_len = bidi_it->ch_len;
+ typ1 = find_first_strong_char (bidi_it->charpos,
+ bidi_it->bytepos, end,
+ &disp_pos, &disp_prop,
+ &bidi_it->string, bidi_it->w,
+ string_p, bidi_it->frame_window_p,
+ &ch_len, &nchars, true);
+ if (typ1 != STRONG_R && typ1 != STRONG_AL)
+ {
+ type = LRI;
+ goto fsi_as_lri;
+ }
+ else
+ type = RLI;
+ /* FALLTHROUGH */
+ case RLI: /* X5a */
+ if (override == NEUTRAL_DIR)
+ bidi_it->type_after_wn = type;
+ else /* Unicode 8.0 correction. */
+ bidi_it->type_after_wn = (override == L2R ? STRONG_L : STRONG_R);
+ bidi_check_type (bidi_it->type_after_wn);
+ break;
+ case LRI: /* X5b */
+ fsi_as_lri:
+ if (override == NEUTRAL_DIR)
+ bidi_it->type_after_wn = type;
+ else /* Unicode 8.0 correction. */
+ bidi_it->type_after_wn = (override == L2R ? STRONG_L : STRONG_R);
+ bidi_check_type (bidi_it->type_after_wn);
+ break;
+ case PDI: /* X6a */
+ if (bidi_it->invalid_isolates)
+ bidi_it->invalid_isolates--;
+ else if (bidi_it->isolate_level > 0)
+ {
+ bidi_it->invalid_levels = 0;
+ while (!ISOLATE_STATUS (bidi_it, bidi_it->stack_idx))
+ bidi_pop_embedding_level (bidi_it);
+ eassert (bidi_it->stack_idx > 0);
+ new_level = bidi_pop_embedding_level (bidi_it);
+ bidi_it->isolate_level--;
+ }
+ bidi_it->resolved_level = new_level;
+ /* Unicode 8.0 correction. */
+ {
+ bidi_dir_t stack_override = OVERRIDE (bidi_it, bidi_it->stack_idx);
+ if (stack_override == L2R)
+ bidi_it->type_after_wn = STRONG_L;
+ else if (stack_override == R2L)
+ bidi_it->type_after_wn = STRONG_R;
+ else
+ bidi_it->type_after_wn = type;
+ }
+ break;
+ case PDF: /* X7 */
+ bidi_it->type_after_wn = type;
+ bidi_check_type (bidi_it->type_after_wn);
+ type = WEAK_BN; /* X9/Retaining */
+ break;
+ default:
+ /* Nothing. */
+ break;
}
+ bidi_it->type = type;
+ bidi_check_type (bidi_it->type);
+
if (bidi_it->type == NEUTRAL_B) /* X8 */
{
bidi_set_paragraph_end (bidi_it);
/* This is needed by bidi_resolve_weak below, and in L1. */
- bidi_it->type_after_w1 = bidi_it->type;
- bidi_check_type (bidi_it->type_after_w1);
+ bidi_it->type_after_wn = bidi_it->type;
}
- return new_level;
+ eassert (bidi_it->resolved_level >= 0);
+ return bidi_it->resolved_level;
}
/* Advance in the buffer/string, resolve weak types and return the
? bidi_it->string.schars : ZV);
type = bidi_it->type;
- override = bidi_it->level_stack[bidi_it->stack_idx].override;
-
- if (type == UNKNOWN_BT
- || type == LRE
- || type == LRO
- || type == RLE
- || type == RLO
- || type == PDF)
- emacs_abort ();
+ override = OVERRIDE (bidi_it, bidi_it->stack_idx);
+
+ eassert (!(type == UNKNOWN_BT
+ || type == LRE
+ || type == LRO
+ || type == RLE
+ || type == RLO
+ || type == PDF));
- if (new_level != prev_level
- || bidi_it->type == NEUTRAL_B)
+ eassert (prev_level >= 0);
+ if (bidi_it->type == NEUTRAL_B)
{
- /* We've got a new embedding level run, compute the directional
- type of sor and initialize per-run variables (UAX#9, clause
+ /* We've got a new isolating sequence, compute the directional
+ type of sos and initialize per-run variables (UAX#9, clause
X10). */
- bidi_set_sor_type (bidi_it, prev_level, new_level);
+ bidi_set_sos_type (bidi_it, prev_level, new_level);
}
- else if (type == NEUTRAL_S || type == NEUTRAL_WS
- || type == WEAK_BN || type == STRONG_AL)
- bidi_it->type_after_w1 = type; /* needed in L1 */
- bidi_check_type (bidi_it->type_after_w1);
+ if (type == NEUTRAL_S || type == NEUTRAL_WS
+ || type == WEAK_BN || type == STRONG_AL)
+ bidi_it->type_after_wn = type; /* needed in L1 */
+ bidi_check_type (bidi_it->type_after_wn);
/* Level and directional override status are already recorded in
bidi_it, and do not need any change; see X6. */
because then either the type of this NSM would have been
also overridden, or the previous character is outside the
current level run, and thus not relevant to this NSM.
- This is why NSM gets the type_after_w1 of the previous
+ This is why NSM gets the type_after_wn of the previous
character. */
- if (bidi_it->prev.type_after_w1 != UNKNOWN_BT
- /* if type_after_w1 is NEUTRAL_B, this NSM is at sor */
- && bidi_it->prev.type_after_w1 != NEUTRAL_B)
- type = bidi_it->prev.type_after_w1;
- else if (bidi_it->sor == R2L)
+ /* bidi_set_sos_type sets type_after_wn to UNKNOWN_BT. */
+ if (bidi_it->prev.type != UNKNOWN_BT
+ /* If type_after_wn is NEUTRAL_B, this NSM is at sos. */
+ && bidi_it->prev.type != NEUTRAL_B)
+ {
+ if (bidi_isolate_fmt_char (bidi_it->prev.type))
+ {
+ /* From W1: "Note that in an isolating run sequence,
+ an isolate initiator followed by an NSM or any
+ type other than PDI must be an overflow isolate
+ initiator." */
+ eassert (bidi_it->invalid_isolates > 0);
+ type = NEUTRAL_ON;
+ }
+ else
+ {
+ /* This includes the Unicode 8.0 correction for N0,
+ due to how we set prev.type in bidi_resolve_explicit,
+ which see. */
+ type = bidi_it->prev.type;
+ }
+ }
+ else if (bidi_it->sos == R2L)
type = STRONG_R;
- else if (bidi_it->sor == L2R)
+ else if (bidi_it->sos == L2R)
type = STRONG_L;
else /* shouldn't happen! */
emacs_abort ();
}
if (type == WEAK_EN /* W2 */
- && bidi_it->last_strong.type_after_w1 == STRONG_AL)
+ && bidi_it->last_strong.type == STRONG_AL)
type = WEAK_AN;
else if (type == STRONG_AL) /* W3 */
type = STRONG_R;
else if ((type == WEAK_ES /* W4 */
- && bidi_it->prev.type_after_w1 == WEAK_EN
+ && bidi_it->prev.type == WEAK_EN
&& bidi_it->prev.orig_type == WEAK_EN)
|| (type == WEAK_CS
- && ((bidi_it->prev.type_after_w1 == WEAK_EN
+ && ((bidi_it->prev.type == WEAK_EN
&& bidi_it->prev.orig_type == WEAK_EN)
- || bidi_it->prev.type_after_w1 == WEAK_AN)))
+ || bidi_it->prev.type == WEAK_AN)))
{
const unsigned char *s
= (STRINGP (bidi_it->string.lstring)
bidi_copy_it (&saved_it, bidi_it);
while (bidi_resolve_explicit (bidi_it) == new_level
&& bidi_it->type == WEAK_BN)
- ;
- type_of_next = bidi_it->type;
+ type_of_next = bidi_it->type;
bidi_copy_it (bidi_it, &saved_it);
}
should not be changed into EN. */
if (type == WEAK_ES
&& type_of_next == WEAK_EN
- && bidi_it->last_strong.type_after_w1 != STRONG_AL)
+ && bidi_it->last_strong.type != STRONG_AL)
type = WEAK_EN;
else if (type == WEAK_CS)
{
- if (bidi_it->prev.type_after_w1 == WEAK_AN
+ if (bidi_it->prev.type == WEAK_AN
&& (type_of_next == WEAK_AN
/* If the next character is EN, but the last
strong-type character is AL, EN will be later
So in that case, this ES should not be
changed into EN. */
|| (type_of_next == WEAK_EN
- && bidi_it->last_strong.type_after_w1 == STRONG_AL)))
+ && bidi_it->last_strong.type == STRONG_AL)))
type = WEAK_AN;
- else if (bidi_it->prev.type_after_w1 == WEAK_EN
+ else if (bidi_it->prev.type == WEAK_EN
&& type_of_next == WEAK_EN
- && bidi_it->last_strong.type_after_w1 != STRONG_AL)
+ && bidi_it->last_strong.type != STRONG_AL)
type = WEAK_EN;
}
}
else if (type == WEAK_ET /* W5: ET with EN before or after it */
|| type == WEAK_BN) /* W5/Retaining */
{
- if (bidi_it->prev.type_after_w1 == WEAK_EN) /* ET/BN w/EN before it */
+ if (bidi_it->prev.type == WEAK_EN) /* ET/BN w/EN before it */
type = WEAK_EN;
else if (bidi_it->next_en_pos > bidi_it->charpos
&& bidi_it->next_en_type != WEAK_BN)
}
else if (bidi_it->next_en_pos >=0)
{
+ /* We overstepped the last known position for ET
+ resolution but there could be other such characters
+ in this paragraph (when we are sure there are no more
+ such positions, we set next_en_pos to a negative
+ value). Try to find the next position for ET
+ resolution. */
ptrdiff_t en_pos = bidi_it->charpos + bidi_it->nchars;
const unsigned char *s = (STRINGP (bidi_it->string.lstring)
? SDATA (bidi_it->string.lstring)
while (bidi_resolve_explicit (bidi_it) == new_level
&& (bidi_it->type == WEAK_BN
|| bidi_it->type == WEAK_ET))
- ;
- type_of_next = bidi_it->type;
- en_pos = bidi_it->charpos;
+ type_of_next = bidi_it->type;
+ if (type == WEAK_BN
+ && bidi_it->charpos == saved_it.charpos + saved_it.nchars)
+ {
+ /* If we entered the above loop with a BN that
+ changes the level, the type of next
+ character, which is in a different level, is
+ not relevant to resolving this series of ET
+ and BN. */
+ en_pos = saved_it.charpos;
+ type_of_next = type;
+ }
+ else
+ en_pos = bidi_it->charpos;
bidi_copy_it (bidi_it, &saved_it);
}
/* Remember this position, to speed up processing of the
{
/* If the last strong character is AL, the EN we've
found will become AN when we get to it (W2). */
- if (bidi_it->last_strong.type_after_w1 == STRONG_AL)
+ if (bidi_it->last_strong.type == STRONG_AL)
type_of_next = WEAK_AN;
else if (type == WEAK_BN)
type = NEUTRAL_ON; /* W6/Retaining */
if (type == WEAK_ES || type == WEAK_ET || type == WEAK_CS /* W6 */
|| (type == WEAK_BN
- && (bidi_it->prev.type_after_w1 == WEAK_CS /* W6/Retaining */
- || bidi_it->prev.type_after_w1 == WEAK_ES
- || bidi_it->prev.type_after_w1 == WEAK_ET)))
+ && (bidi_it->prev.type == WEAK_CS /* W6/Retaining */
+ || bidi_it->prev.type == WEAK_ES
+ || bidi_it->prev.type == WEAK_ET)))
type = NEUTRAL_ON;
/* Store the type we've got so far, before we clobber it with strong
types in W7 and while resolving neutral types. But leave alone
the original types that were recorded above, because we will need
them for the L1 clause. */
- if (bidi_it->type_after_w1 == UNKNOWN_BT)
- bidi_it->type_after_w1 = type;
- bidi_check_type (bidi_it->type_after_w1);
+ if (bidi_it->type_after_wn == UNKNOWN_BT)
+ bidi_it->type_after_wn = type;
+ bidi_check_type (bidi_it->type_after_wn);
if (type == WEAK_EN) /* W7 */
{
- if ((bidi_it->last_strong.type_after_w1 == STRONG_L)
- || (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sor == L2R))
+ if ((bidi_it->last_strong.type == STRONG_L)
+ || (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sos == L2R))
type = STRONG_L;
}
static bidi_type_t
bidi_resolve_neutral_1 (bidi_type_t prev_type, bidi_type_t next_type, int lev)
{
- /* N1: European and Arabic numbers are treated as though they were R. */
+ /* N1: "European and Arabic numbers act as if they were R in terms
+ of their influence on NIs." */
if (next_type == WEAK_EN || next_type == WEAK_AN)
next_type = STRONG_R;
if (prev_type == WEAK_EN || prev_type == WEAK_AN)
return STRONG_R;
}
+#define FLAG_EMBEDDING_INSIDE 1
+#define FLAG_OPPOSITE_INSIDE 2
+
+/* A data type used in the stack maintained by
+ bidi_find_bracket_pairs below. */
+typedef struct bpa_stack_entry {
+ int close_bracket_char;
+ int open_bracket_idx;
+#ifdef ENABLE_CHECKING
+ ptrdiff_t open_bracket_pos;
+#endif
+ unsigned flags : 2;
+} bpa_stack_entry;
+
+/* With MAX_ALLOCA of 16KB, this should allow at least 1K slots in the
+ BPA stack, which should be more than enough for actual bidi text. */
+#define MAX_BPA_STACK ((int)max (MAX_ALLOCA / sizeof (bpa_stack_entry), 1))
+
+/* UAX#9 says to match opening brackets with the matching closing
+ brackets or their canonical equivalents. As of Unicode 7.0, there
+ are only 2 bracket characters that have canonical equivalence
+ decompositions: u+2329 and u+232A. So instead of accessing the
+ table in uni-decomposition.el, we just handle these 2 characters
+ with this simple macro. Note that ASCII characters don't have
+ canonical equivalents by definition. */
+
+/* To find all the characters that need to be processed by
+ CANONICAL_EQU, first find all the characters which have
+ decompositions in UnicodeData.txt, with this Awk script:
+
+ awk -F ";" " {if ($6 != \"\") print $1, $6}" UnicodeData.txt
+
+ Then produce a list of all the bracket characters in BidiBrackets.txt:
+
+ awk -F "[ ;]" " {if ($1 != \"#\" && $1 != \"\") print $1}" BidiBrackets.txt
+
+ And finally, cross-reference these two:
+
+ fgrep -w -f brackets.txt decompositions.txt
+
+ where "decompositions.txt" was produced by the 1st script, and
+ "brackets.txt" by the 2nd script. In the output of fgrep, look
+ only for decompositions that don't begin with some compatibility
+ formatting tag, such as "<compat>". Only decompositions that
+ consist solely of character codepoints are relevant to bidi
+ brackets processing. */
+
+#define CANONICAL_EQU(c) \
+ ( ASCII_CHAR_P (c) ? c \
+ : (c) == 0x2329 ? 0x3008 \
+ : (c) == 0x232a ? 0x3009 \
+ : c )
+
+#ifdef ENABLE_CHECKING
+# define STORE_BRACKET_CHARPOS \
+ bpa_stack[bpa_sp].open_bracket_pos = bidi_it->charpos
+#else
+# define STORE_BRACKET_CHARPOS /* nothing */
+#endif
+
+#define PUSH_BPA_STACK \
+ do { \
+ int ch; \
+ if (bpa_sp < MAX_BPA_STACK - 1) \
+ { \
+ bpa_sp++; \
+ ch = CANONICAL_EQU (bidi_it->ch); \
+ bpa_stack[bpa_sp].close_bracket_char = bidi_mirror_char (ch); \
+ bpa_stack[bpa_sp].open_bracket_idx = bidi_cache_last_idx; \
+ bpa_stack[bpa_sp].flags = 0; \
+ STORE_BRACKET_CHARPOS; \
+ } \
+ } while (0)
+
+
+/* This function implements BPA, the Bidi Parenthesis Algorithm,
+ described in BD16 and N0 of UAX#9. It finds all the bracket pairs
+ in the current isolating sequence, and records the enclosed type
+ and the position of the matching bracket in the cache. It returns
+ non-zero if called with the iterator on the opening bracket which
+ has a matching closing bracket in the current isolating sequence,
+ zero otherwise. */
+static bool
+bidi_find_bracket_pairs (struct bidi_it *bidi_it)
+{
+ bidi_bracket_type_t btype;
+ bidi_type_t type = bidi_it->type;
+ bool retval = false;
+
+ /* When scanning backwards, we don't expect any unresolved bidi
+ bracket characters. */
+ if (bidi_it->scan_dir != 1)
+ emacs_abort ();
+
+ btype = bidi_paired_bracket_type (bidi_it->ch);
+ if (btype == BIDI_BRACKET_OPEN)
+ {
+ bpa_stack_entry bpa_stack[MAX_BPA_STACK];
+ int bpa_sp = -1;
+ struct bidi_it saved_it;
+ int base_level = bidi_it->level_stack[0].level;
+ int embedding_level = bidi_it->level_stack[bidi_it->stack_idx].level;
+ int maxlevel = embedding_level;
+ bidi_type_t embedding_type = (embedding_level & 1) ? STRONG_R : STRONG_L;
+ struct bidi_it tem_it;
+ bool l2r_seen = false, r2l_seen = false;
+ ptrdiff_t pairing_pos;
+ int idx_at_entry = bidi_cache_idx;
+
+ eassert (MAX_BPA_STACK >= 100);
+ bidi_copy_it (&saved_it, bidi_it);
+ /* bidi_cache_iterator_state refuses to cache on backward scans,
+ and bidi_cache_fetch_state doesn't bring scan_dir from the
+ cache, so we must initialize this explicitly. */
+ tem_it.scan_dir = 1;
+
+ while (1)
+ {
+ int old_sidx, new_sidx;
+ int current_level = bidi_it->level_stack[bidi_it->stack_idx].level;
+
+ if (maxlevel < current_level)
+ maxlevel = current_level;
+ /* Mark every opening bracket character we've traversed by
+ putting its own position into bracket_pairing_pos. This
+ is examined in bidi_resolve_brackets to distinguish
+ brackets that were already resolved to stay NEUTRAL_ON,
+ and those that were not yet processed by this function
+ (because they were skipped when we skip higher embedding
+ levels below). */
+ if (btype == BIDI_BRACKET_OPEN && bidi_it->bracket_pairing_pos == -1)
+ bidi_it->bracket_pairing_pos = bidi_it->charpos;
+ if (!bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B, 0))
+ {
+ /* No more space in cache -- give up and let the opening
+ bracket that started this be processed as a
+ NEUTRAL_ON. */
+ bidi_cache_reset_to (idx_at_entry - bidi_cache_start);
+ bidi_copy_it (bidi_it, &saved_it);
+ goto give_up;
+ }
+ if (btype == BIDI_BRACKET_OPEN)
+ PUSH_BPA_STACK;
+ else if (btype == BIDI_BRACKET_CLOSE)
+ {
+ int sp = bpa_sp;
+ int curchar = CANONICAL_EQU (bidi_it->ch);
+
+ eassert (sp >= 0);
+ while (sp >= 0 && bpa_stack[sp].close_bracket_char != curchar)
+ sp--;
+ if (sp >= 0)
+ {
+ /* Update and cache the corresponding opening bracket. */
+ bidi_cache_fetch_state (bpa_stack[sp].open_bracket_idx,
+ &tem_it);
+#ifdef ENABLE_CHECKING
+ eassert (bpa_stack[sp].open_bracket_pos == tem_it.charpos);
+#endif
+ /* Determine the enclosed type for this bracket
+ pair's type resolution according to N0. */
+ if (bpa_stack[sp].flags & FLAG_EMBEDDING_INSIDE)
+ tem_it.bracket_enclosed_type = embedding_type; /* N0b */
+ else if (bpa_stack[sp].flags & FLAG_OPPOSITE_INSIDE)
+ tem_it.bracket_enclosed_type /* N0c */
+ = (embedding_type == STRONG_L ? STRONG_R : STRONG_L);
+ else /* N0d */
+ tem_it.bracket_enclosed_type = UNKNOWN_BT;
+
+ /* Record the position of the matching closing
+ bracket, and update the cache. */
+ tem_it.bracket_pairing_pos = bidi_it->charpos;
+ bidi_cache_iterator_state (&tem_it, 0, 1);
+
+ /* Pop the BPA stack. */
+ bpa_sp = sp - 1;
+ }
+ if (bpa_sp < 0)
+ {
+ retval = true;
+ break;
+ }
+ }
+ else if (bidi_get_category (bidi_it->type_after_wn) != NEUTRAL)
+ {
+ unsigned flag = 0;
+ int sp;
+
+ /* Whenever we see a strong type, update the flags of
+ all the slots on the stack. */
+ switch (bidi_it->type)
+ {
+ case STRONG_L:
+ flag = ((embedding_level & 1) == 0
+ ? FLAG_EMBEDDING_INSIDE
+ : FLAG_OPPOSITE_INSIDE);
+ l2r_seen = true;
+ break;
+ case STRONG_R:
+ case WEAK_EN:
+ case WEAK_AN:
+ flag = ((embedding_level & 1) == 1
+ ? FLAG_EMBEDDING_INSIDE
+ : FLAG_OPPOSITE_INSIDE);
+ r2l_seen = true;
+ break;
+ default:
+ break;
+ }
+ if (flag)
+ {
+ for (sp = bpa_sp; sp >= 0; sp--)
+ bpa_stack[sp].flags |= flag;
+ }
+ }
+ old_sidx = bidi_it->stack_idx;
+ type = bidi_resolve_weak (bidi_it);
+ /* Skip level runs excluded from this isolating run sequence. */
+ new_sidx = bidi_it->stack_idx;
+ if (bidi_it->level_stack[new_sidx].level > current_level
+ && (ISOLATE_STATUS (bidi_it, new_sidx)
+ || (new_sidx > old_sidx + 1
+ && ISOLATE_STATUS (bidi_it, new_sidx - 1))))
+ {
+ while (bidi_it->level_stack[bidi_it->stack_idx].level
+ > current_level)
+ {
+ if (maxlevel < bidi_it->level_stack[bidi_it->stack_idx].level)
+ maxlevel = bidi_it->level_stack[bidi_it->stack_idx].level;
+ if (!bidi_cache_iterator_state (bidi_it,
+ type == NEUTRAL_B, 0))
+ {
+ /* No more space in cache -- give up and let the
+ opening bracket that started this be
+ processed as any other NEUTRAL_ON. */
+ bidi_cache_reset_to (idx_at_entry - bidi_cache_start);
+ bidi_copy_it (bidi_it, &saved_it);
+ goto give_up;
+ }
+ type = bidi_resolve_weak (bidi_it);
+ }
+ }
+ if (type == NEUTRAL_B
+ || (bidi_it->level_stack[bidi_it->stack_idx].level
+ != current_level))
+ {
+ /* We've marched all the way to the end of this
+ isolating run sequence, and didn't find matching
+ closing brackets for some opening brackets. Leave
+ their type unchanged. */
+ pairing_pos = bidi_it->charpos;
+ break;
+ }
+ if (bidi_it->type_after_wn == NEUTRAL_ON) /* Unicode 8.0 correction */
+ btype = bidi_paired_bracket_type (bidi_it->ch);
+ else
+ btype = BIDI_BRACKET_NONE;
+ }
+
+ /* Restore bidi_it from the cache, which should have the bracket
+ resolution members set as determined by the above loop. */
+ type = bidi_cache_find (saved_it.charpos, 0, bidi_it);
+ eassert (type == NEUTRAL_ON);
+
+ /* The following is an optimization for bracketed text that has
+ only one level which is equal to the paragraph's base
+ embedding level. That is, only L2R and weak/neutral
+ characters in a L2R paragraph, or only R2L and weak/neutral
+ characters in a R2L paragraph. Such brackets can be resolved
+ by bidi_resolve_neutral, which has a further shortcut for
+ this case. So we pretend we did not resolve the brackets in
+ this case, set up next_for_neutral for the entire bracketed
+ text, and reset the cache to the character before the opening
+ bracket. The upshot is to allow bidi_move_to_visually_next
+ reset the cache when it returns this opening bracket, thus
+ cutting significantly on the size of the cache, which is
+ important with long lines, especially if word-wrap is non-nil
+ (which requires the display engine to copy the cache back and
+ forth many times). */
+ if (maxlevel == base_level
+ && ((base_level == 0 && !r2l_seen)
+ || (base_level == 1 && !l2r_seen)))
+ {
+ ptrdiff_t eob
+ = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
+ ? bidi_it->string.schars : ZV);
+
+ if (retval)
+ pairing_pos = bidi_it->bracket_pairing_pos;
+
+ /* This special value (which cannot possibly happen when
+ brackets are resolved, since there's no character at ZV)
+ will be noticed by bidi_resolve_explicit, and will be
+ copied to the following iterator states, instead of being
+ reset to -1. */
+ bidi_it->bracket_pairing_pos = eob;
+ /* This type value will be used for resolving the outermost
+ closing bracket in bidi_resolve_brackets. */
+ bidi_it->bracket_enclosed_type = embedding_type;
+ /* bidi_cache_last_idx is set to the index of the current
+ state, because we just called bidi_cache_find above.
+ That state describes the outermost opening bracket, the
+ one with which we entered this function. Force the cache
+ to "forget" all the cached states starting from that state. */
+ bidi_cache_reset_to (bidi_cache_last_idx - bidi_cache_start);
+ /* Set up the next_for_neutral member, to help
+ bidi_resolve_neutral. */
+ bidi_it->next_for_neutral.type = embedding_type;
+ bidi_it->next_for_neutral.charpos = pairing_pos;
+ /* Pretend we didn't resolve this bracket. */
+ retval = false;
+ }
+ }
+
+ give_up:
+ return retval;
+}
+
+static void
+bidi_record_type_for_neutral (struct bidi_saved_info *info, int level,
+ bool nextp)
+{
+ int idx;
+
+ for (idx = bidi_cache_last_idx + 1; idx < bidi_cache_idx; idx++)
+ {
+ int lev = bidi_cache[idx].level_stack[bidi_cache[idx].stack_idx].level;
+
+ if (lev <= level)
+ {
+ eassert (lev == level);
+ if (nextp)
+ bidi_cache[idx].next_for_neutral = *info;
+ else
+ bidi_cache[idx].prev_for_neutral = *info;
+ break;
+ }
+ }
+}
+
static bidi_type_t
-bidi_resolve_neutral (struct bidi_it *bidi_it)
+bidi_resolve_brackets (struct bidi_it *bidi_it)
{
int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level;
- bidi_type_t type = bidi_resolve_weak (bidi_it);
- int current_level = bidi_it->level_stack[bidi_it->stack_idx].level;
-
- if (!(type == STRONG_R
- || type == STRONG_L
- || type == WEAK_BN
- || type == WEAK_EN
- || type == WEAK_AN
- || type == NEUTRAL_B
- || type == NEUTRAL_S
- || type == NEUTRAL_WS
- || type == NEUTRAL_ON))
- emacs_abort ();
+ bool resolve_bracket = false;
+ bidi_type_t type = UNKNOWN_BT;
+ int ch;
+ struct bidi_saved_info prev_for_neutral, next_for_neutral;
+ ptrdiff_t eob
+ = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
+ ? bidi_it->string.schars : ZV);
+
+ /* Record the prev_for_neutral type either from the previous
+ character, if it was a strong or AN/EN, or from the
+ prev_for_neutral information recorded previously. */
+ if (bidi_it->type == STRONG_L || bidi_it->type == STRONG_R
+ || bidi_it->type == WEAK_AN || bidi_it->type == WEAK_EN)
+ bidi_remember_char (&prev_for_neutral, bidi_it, 1);
+ else
+ prev_for_neutral = bidi_it->prev_for_neutral;
+ /* Record the next_for_neutral type information. */
+ if (bidi_it->next_for_neutral.charpos > bidi_it->charpos)
+ next_for_neutral = bidi_it->next_for_neutral;
+ else
+ next_for_neutral.charpos = -1;
+ if (!bidi_it->first_elt)
+ {
+ type = bidi_cache_find (bidi_it->charpos + bidi_it->nchars, 0, bidi_it);
+ ch = bidi_it->ch;
+ }
+ if (type == UNKNOWN_BT)
+ {
+ type = bidi_resolve_weak (bidi_it);
+ if (type == NEUTRAL_ON)
+ {
+ /* bracket_pairing_pos == eob means this bracket does not
+ need to be resolved as a bracket, but as a neutral, see
+ the optimization trick we play near the end of
+ bidi_find_bracket_pairs. */
+ if (bidi_it->bracket_pairing_pos == eob)
+ {
+ /* If this is the outermost closing bracket of a run of
+ characters in which we decided to resolve brackets as
+ neutrals, use the embedding level's type, recorded in
+ bracket_enclosed_type, to resolve the bracket. */
+ if (bidi_it->next_for_neutral.charpos == bidi_it->charpos
+ && bidi_paired_bracket_type (bidi_it->ch) == BIDI_BRACKET_CLOSE)
+ type = bidi_it->bracket_enclosed_type;
+ }
+ else if (bidi_find_bracket_pairs (bidi_it))
+ resolve_bracket = true;
+ }
+ }
+ else if (bidi_it->bracket_pairing_pos != eob)
+ {
+ eassert (bidi_it->resolved_level == -1);
+ /* If the cached state shows an increase of embedding level due
+ to an isolate initiator, we need to update the 1st cached
+ state of the next run of the current isolating sequence with
+ the prev_for_neutral and next_for_neutral information, so
+ that it will be picked up when we advance to that next run. */
+ if (bidi_it->level_stack[bidi_it->stack_idx].level > prev_level
+ && ISOLATE_STATUS (bidi_it, bidi_it->stack_idx))
+ {
+ bidi_record_type_for_neutral (&prev_for_neutral, prev_level, 0);
+ bidi_record_type_for_neutral (&next_for_neutral, prev_level, 1);
+ }
+ if (type == NEUTRAL_ON
+ && bidi_paired_bracket_type (ch) == BIDI_BRACKET_OPEN)
+ {
+ if (bidi_it->bracket_pairing_pos > bidi_it->charpos)
+ {
+ /* A cached opening bracket that wasn't completely
+ resolved yet. */
+ resolve_bracket = true;
+ }
+ else if (bidi_it->bracket_pairing_pos == -1)
+ {
+ /* Higher levels were not BPA-resolved yet, even if
+ cached by bidi_find_bracket_pairs. Force application
+ of BPA to the new level now. */
+ if (bidi_find_bracket_pairs (bidi_it))
+ resolve_bracket = true;
+ }
+ }
+ /* Keep track of the prev_for_neutral and next_for_neutral
+ types, needed for resolving brackets below and for resolving
+ neutrals in bidi_resolve_neutral. */
+ if (bidi_it->level_stack[bidi_it->stack_idx].level == prev_level)
+ {
+ bidi_it->prev_for_neutral = prev_for_neutral;
+ if (next_for_neutral.charpos > 0)
+ bidi_it->next_for_neutral = next_for_neutral;
+ }
+ }
+
+ /* If needed, resolve the bracket type according to N0. */
+ if (resolve_bracket)
+ {
+ int embedding_level = bidi_it->level_stack[bidi_it->stack_idx].level;
+ bidi_type_t embedding_type = (embedding_level & 1) ? STRONG_R : STRONG_L;
+
+ eassert (bidi_it->prev_for_neutral.type != UNKNOWN_BT);
+ eassert (bidi_it->bracket_pairing_pos > bidi_it->charpos);
+ if (bidi_it->bracket_enclosed_type == embedding_type) /* N0b */
+ type = embedding_type;
+ else
+ {
+ switch (bidi_it->prev_for_neutral.type)
+ {
+ case STRONG_R:
+ case WEAK_EN:
+ case WEAK_AN:
+ type =
+ (bidi_it->bracket_enclosed_type == STRONG_R) /* N0c */
+ ? STRONG_R /* N0c1 */
+ : embedding_type; /* N0c2 */
+ break;
+ case STRONG_L:
+ type =
+ (bidi_it->bracket_enclosed_type == STRONG_L) /* N0c */
+ ? STRONG_L /* N0c1 */
+ : embedding_type; /* N0c2 */
+ break;
+ default:
+ /* N0d: Do not set the type for that bracket pair. */
+ break;
+ }
+ }
+ eassert (type == STRONG_L || type == STRONG_R || type == NEUTRAL_ON);
+
+ /* Update the type of the paired closing bracket to the same
+ type as for the resolved opening bracket. */
+ if (type != NEUTRAL_ON)
+ {
+ ptrdiff_t idx = bidi_cache_search (bidi_it->bracket_pairing_pos,
+ -1, 1);
+
+ if (idx < bidi_cache_start)
+ emacs_abort ();
+ bidi_cache[idx].type = type;
+ }
+ }
+
+ return type;
+}
+
+static bidi_type_t
+bidi_resolve_neutral (struct bidi_it *bidi_it)
+{
+ bidi_type_t type = bidi_resolve_brackets (bidi_it);
+ int current_level;
+ bool is_neutral;
+
+ eassert (type == STRONG_R
+ || type == STRONG_L
+ || type == WEAK_BN
+ || type == WEAK_EN
+ || type == WEAK_AN
+ || type == NEUTRAL_B
+ || type == NEUTRAL_S
+ || type == NEUTRAL_WS
+ || type == NEUTRAL_ON
+ || type == LRI
+ || type == RLI
+ || type == PDI);
+
+ current_level = bidi_it->level_stack[bidi_it->stack_idx].level;
+ eassert (current_level >= 0);
+ is_neutral = bidi_get_category (type) == NEUTRAL;
if ((type != NEUTRAL_B /* Don't risk entering the long loop below if
we are already at paragraph end. */
- && bidi_get_category (type) == NEUTRAL)
- || (type == WEAK_BN && prev_level == current_level))
+ && (is_neutral || bidi_isolate_fmt_char (type)))
+ /* N1-N2/Retaining */
+ || (type == WEAK_BN && bidi_explicit_dir_char (bidi_it->ch)))
{
if (bidi_it->next_for_neutral.type != UNKNOWN_BT)
- type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
- bidi_it->next_for_neutral.type,
- current_level);
+ {
+ /* Make sure the data for resolving neutrals we are
+ about to use is valid. */
+ eassert (bidi_it->next_for_neutral.charpos > bidi_it->charpos
+ /* PDI defines an eos, so it's OK for it to
+ serve as its own next_for_neutral. */
+ || (bidi_it->next_for_neutral.charpos == bidi_it->charpos
+ && bidi_it->type == PDI));
+ type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
+ bidi_it->next_for_neutral.type,
+ current_level);
+ }
/* The next two "else if" clauses are shortcuts for the
important special case when we have a long sequence of
neutral or WEAK_BN characters, such as whitespace or nulls or
entering the expensive loop in the "else" clause. */
else if (current_level == 0
&& bidi_it->prev_for_neutral.type == STRONG_L
- && !bidi_explicit_dir_char (bidi_it->ch))
+ && !bidi_explicit_dir_char (bidi_it->ch)
+ && !bidi_isolate_fmt_char (type))
type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
STRONG_L, current_level);
else if (/* current level is 1 */
&& (bidi_it->prev_for_neutral.type == STRONG_R
|| bidi_it->prev_for_neutral.type == WEAK_EN
|| bidi_it->prev_for_neutral.type == WEAK_AN)
- && !bidi_explicit_dir_char (bidi_it->ch))
+ && !bidi_explicit_dir_char (bidi_it->ch)
+ && !bidi_isolate_fmt_char (type))
type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
STRONG_R, current_level);
else
implementations! */
struct bidi_it saved_it;
bidi_type_t next_type;
-
- if (bidi_it->scan_dir == -1)
- emacs_abort ();
+ bool adjacent_to_neutrals = is_neutral;
bidi_copy_it (&saved_it, bidi_it);
/* Scan the text forward until we find the first non-neutral
character, and then use that to resolve the neutral we
are dealing with now. We also cache the scanned iterator
states, to salvage some of the effort later. */
- bidi_cache_iterator_state (bidi_it, 0);
do {
- /* Record the info about the previous character, so that
- it will be cached below with this state. */
- if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */
- && bidi_it->type != WEAK_BN)
- bidi_remember_char (&bidi_it->prev, bidi_it);
- type = bidi_resolve_weak (bidi_it);
+ int old_sidx, new_sidx;
+
/* Paragraph separators have their levels fully resolved
at this point, so cache them as resolved. */
- bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B);
- /* FIXME: implement L1 here, by testing for a newline and
- resetting the level for any sequence of whitespace
- characters adjacent to it. */
+ bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B, 0);
+ old_sidx = bidi_it->stack_idx;
+ type = bidi_resolve_brackets (bidi_it);
+ /* Skip level runs excluded from this isolating run sequence. */
+ new_sidx = bidi_it->stack_idx;
+ if (bidi_it->level_stack[new_sidx].level > current_level
+ && (ISOLATE_STATUS (bidi_it, new_sidx)
+ /* This is for when we have an isolate initiator
+ immediately followed by an embedding or
+ override initiator, in which case we get the
+ level stack pushed twice by the single call to
+ bidi_resolve_weak above. */
+ || (new_sidx > old_sidx + 1
+ && ISOLATE_STATUS (bidi_it, new_sidx - 1))))
+ {
+ while (bidi_it->level_stack[bidi_it->stack_idx].level
+ > current_level)
+ {
+ bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B, 0);
+ type = bidi_resolve_brackets (bidi_it);
+ }
+ }
+ if (!adjacent_to_neutrals
+ && (bidi_get_category (type) == NEUTRAL
+ || bidi_isolate_fmt_char (type)))
+ adjacent_to_neutrals = true;
} while (!(type == NEUTRAL_B
|| (type != WEAK_BN
- && bidi_get_category (type) != NEUTRAL)
+ && bidi_get_category (type) != NEUTRAL
+ && !bidi_isolate_fmt_char (type))
/* This is all per level run, so stop when we
reach the end of this level run. */
|| (bidi_it->level_stack[bidi_it->stack_idx].level
!= current_level)));
- bidi_remember_char (&saved_it.next_for_neutral, bidi_it);
+ /* Record the character we stopped at. */
+ bidi_remember_char (&saved_it.next_for_neutral, bidi_it, 1);
- switch (type)
+ if ((bidi_it->level_stack[bidi_it->stack_idx].level != current_level)
+ || type == NEUTRAL_B)
{
- case STRONG_L:
- case STRONG_R:
- case STRONG_AL:
- /* Actually, STRONG_AL cannot happen here, because
- bidi_resolve_weak converts it to STRONG_R, per W3. */
- eassert (type != STRONG_AL);
- next_type = type;
- break;
- case WEAK_EN:
- case WEAK_AN:
- /* N1: ``European and Arabic numbers are treated as
- though they were R.'' */
- next_type = STRONG_R;
- break;
- case WEAK_BN:
- case NEUTRAL_ON: /* W6/Retaining */
- if (!bidi_explicit_dir_char (bidi_it->ch))
- emacs_abort (); /* can't happen: BNs are skipped */
- /* FALLTHROUGH */
- case NEUTRAL_B:
- /* Marched all the way to the end of this level run.
- We need to use the eor type, whose information is
- stored by bidi_set_sor_type in the prev_for_neutral
- member. */
- if (saved_it.type != WEAK_BN
- || bidi_get_category (bidi_it->prev.type_after_w1) == NEUTRAL)
- next_type = bidi_it->prev_for_neutral.type;
- else
- {
- /* This is a BN which does not adjoin neutrals.
- Leave its type alone. */
- bidi_copy_it (bidi_it, &saved_it);
- return bidi_it->type;
- }
- break;
- default:
- emacs_abort ();
+ /* Marched all the way to the end of this level run. We
+ need to use the eos type, whose information is stored
+ by bidi_set_sos_type in the prev_for_neutral
+ member. */
+ if (adjacent_to_neutrals)
+ next_type = bidi_it->prev_for_neutral.type;
+ else
+ {
+ /* This is a BN which does not adjoin neutrals.
+ Leave its type alone. */
+ bidi_copy_it (bidi_it, &saved_it);
+ return bidi_it->type;
+ }
}
+ else
+ {
+ switch (type)
+ {
+ case STRONG_L:
+ case STRONG_R:
+ case STRONG_AL:
+ /* Actually, STRONG_AL cannot happen here, because
+ bidi_resolve_weak converts it to STRONG_R, per W3. */
+ eassert (type != STRONG_AL);
+ next_type = type;
+ break;
+ case WEAK_EN:
+ case WEAK_AN:
+ /* N1: "European and Arabic numbers act as if they
+ were R in terms of their influence on NIs." */
+ next_type = STRONG_R;
+ break;
+ default:
+ emacs_abort ();
+ break;
+ }
+ }
+ /* Resolve the type of all the NIs found during the above loop. */
type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type,
next_type, current_level);
+ /* Update next_for_neutral with the resolved type, so we
+ could use it for all the other NIs up to the place where
+ we exited the loop. */
saved_it.next_for_neutral.type = next_type;
+ bidi_check_type (type);
+ /* Update the character which caused us to enter the above loop. */
saved_it.type = type;
bidi_check_type (next_type);
- bidi_check_type (type);
bidi_copy_it (bidi_it, &saved_it);
}
}
if (bidi_it->scan_dir != 1)
emacs_abort ();
- /* Reset the limit until which to ignore BNs if we step out of the
- area where we found only empty levels. */
- if ((bidi_it->ignore_bn_limit > -1
- && bidi_it->ignore_bn_limit <= bidi_it->charpos)
- || (bidi_it->ignore_bn_limit == -2
- && !bidi_explicit_dir_char (bidi_it->ch)))
- bidi_it->ignore_bn_limit = -1;
-
type = bidi_resolve_neutral (bidi_it);
return type;
static int
bidi_level_of_next_char (struct bidi_it *bidi_it)
{
- bidi_type_t type;
- int level, prev_level = -1;
- struct bidi_saved_info next_for_neutral;
+ bidi_type_t type = UNKNOWN_BT;
+ int level;
ptrdiff_t next_char_pos = -2;
if (bidi_it->scan_dir == 1)
= ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
? bidi_it->string.schars : ZV);
- /* There's no sense in trying to advance if we hit end of text. */
+ /* There's no sense in trying to advance if we've already hit
+ the end of text. */
if (bidi_it->charpos >= eob)
- return bidi_it->resolved_level;
-
- /* Record the info about the previous character. */
- if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */
- && bidi_it->type != WEAK_BN)
- bidi_remember_char (&bidi_it->prev, bidi_it);
- if (bidi_it->type_after_w1 == STRONG_R
- || bidi_it->type_after_w1 == STRONG_L
- || bidi_it->type_after_w1 == STRONG_AL)
- bidi_remember_char (&bidi_it->last_strong, bidi_it);
- /* FIXME: it sounds like we don't need both prev and
- prev_for_neutral members, but I'm leaving them both for now. */
- if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L
- || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN)
- bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it);
-
- /* If we overstepped the characters used for resolving neutrals
- and whitespace, invalidate their info in the iterator. */
- if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos)
- bidi_it->next_for_neutral.type = UNKNOWN_BT;
- if (bidi_it->next_en_pos >= 0
- && bidi_it->charpos >= bidi_it->next_en_pos)
{
- bidi_it->next_en_pos = 0;
- bidi_it->next_en_type = UNKNOWN_BT;
+ eassert (bidi_it->resolved_level >= 0);
+ return bidi_it->resolved_level;
}
- if (bidi_it->next_for_ws.type != UNKNOWN_BT
- && bidi_it->charpos >= bidi_it->next_for_ws.charpos)
- bidi_it->next_for_ws.type = UNKNOWN_BT;
-
- /* This must be taken before we fill the iterator with the info
- about the next char. If we scan backwards, the iterator
- state must be already cached, so there's no need to know the
- embedding level of the previous character, since we will be
- returning to our caller shortly. */
- prev_level = bidi_it->level_stack[bidi_it->stack_idx].level;
- }
- next_for_neutral = bidi_it->next_for_neutral;
-
- /* Perhaps the character we want is already cached. If it is, the
- call to bidi_cache_find below will return a type other than
- UNKNOWN_BT. */
+ }
+
+ /* Perhaps the character we want is already cached s fully resolved.
+ If it is, the call to bidi_cache_find below will return a type
+ other than UNKNOWN_BT. */
if (bidi_cache_idx > bidi_cache_start && !bidi_it->first_elt)
{
int bob = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
? 0 : 1);
+
if (bidi_it->scan_dir > 0)
{
if (bidi_it->nchars <= 0)
cached at the beginning of the iteration. */
next_char_pos = bidi_it->charpos - 1;
if (next_char_pos >= bob - 1)
- type = bidi_cache_find (next_char_pos, -1, bidi_it);
- else
- type = UNKNOWN_BT;
- }
- else
- type = UNKNOWN_BT;
- if (type != UNKNOWN_BT)
- {
- /* Don't lose the information for resolving neutrals! The
- cached states could have been cached before their
- next_for_neutral member was computed. If we are on our way
- forward, we can simply take the info from the previous
- state. */
- if (bidi_it->scan_dir == 1
- && bidi_it->next_for_neutral.type == UNKNOWN_BT)
- bidi_it->next_for_neutral = next_for_neutral;
-
- /* If resolved_level is -1, it means this state was cached
- before it was completely resolved, so we cannot return
- it. */
- if (bidi_it->resolved_level != -1)
- return bidi_it->resolved_level;
+ type = bidi_cache_find (next_char_pos, 1, bidi_it);
+ if (type != UNKNOWN_BT)
+ {
+ /* We asked the cache for fully resolved states. */
+ eassert (bidi_it->resolved_level >= 0);
+ return bidi_it->resolved_level;
+ }
}
+
if (bidi_it->scan_dir == -1)
/* If we are going backwards, the iterator state is already cached
from previous scans, and should be fully resolved. */
type = bidi_type_of_next_char (bidi_it);
if (type == NEUTRAL_B)
- return bidi_it->resolved_level;
-
- level = bidi_it->level_stack[bidi_it->stack_idx].level;
- if ((bidi_get_category (type) == NEUTRAL /* && type != NEUTRAL_B */)
- || (type == WEAK_BN && prev_level == level))
{
- if (bidi_it->next_for_neutral.type == UNKNOWN_BT)
- emacs_abort ();
-
- /* If the cached state shows a neutral character, it was not
- resolved by bidi_resolve_neutral, so do it now. */
- type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
- bidi_it->next_for_neutral.type,
- level);
+ eassert (bidi_it->resolved_level >= 0);
+ return bidi_it->resolved_level;
}
- if (!(type == STRONG_R
- || type == STRONG_L
- || type == WEAK_BN
- || type == WEAK_EN
- || type == WEAK_AN))
- emacs_abort ();
+ level = bidi_it->level_stack[bidi_it->stack_idx].level;
+
+ eassert ((type == STRONG_R
+ || type == STRONG_L
+ || type == WEAK_BN
+ || type == WEAK_EN
+ || type == WEAK_AN));
bidi_it->type = type;
bidi_check_type (bidi_it->type);
/* For L1 below, we need to know, for each WS character, whether
it belongs to a sequence of WS characters preceding a newline
or a TAB or a paragraph separator. */
- if (bidi_it->orig_type == NEUTRAL_WS
- && bidi_it->next_for_ws.type == UNKNOWN_BT)
+ if ((bidi_it->orig_type == NEUTRAL_WS
+ || bidi_isolate_fmt_char (bidi_it->orig_type))
+ && bidi_it->next_for_ws.charpos < bidi_it->charpos)
{
int ch;
ptrdiff_t clen = bidi_it->ch_len;
do {
ch = bidi_fetch_char (cpos += nc, bpos += clen, &disp_pos, &dpp, &bs,
bidi_it->w, fwp, &clen, &nc);
- if (ch == '\n' || ch == BIDI_EOB)
- chtype = NEUTRAL_B;
- else
- chtype = bidi_get_type (ch, NEUTRAL_DIR);
+ chtype = bidi_get_type (ch, NEUTRAL_DIR);
} while (chtype == NEUTRAL_WS || chtype == WEAK_BN
+ || bidi_isolate_fmt_char (chtype)
|| bidi_explicit_dir_char (ch)); /* L1/Retaining */
bidi_it->next_for_ws.type = chtype;
bidi_check_type (bidi_it->next_for_ws.type);
bidi_it->next_for_ws.charpos = cpos;
- bidi_it->next_for_ws.bytepos = bpos;
}
- /* Resolve implicit levels, with a twist: PDFs get the embedding
- level of the embedding they terminate. See below for the
- reason. */
- if (bidi_it->orig_type == PDF
- /* Don't do this if this formatting code didn't change the
- embedding level due to invalid or empty embeddings. */
- && prev_level != level)
- {
- /* Don't look in UAX#9 for the reason for this: it's our own
- private quirk. The reason is that we want the formatting
- codes to be delivered so that they bracket the text of their
- embedding. For example, given the text
-
- {RLO}teST{PDF}
-
- we want it to be displayed as
-
- {PDF}STet{RLO}
-
- not as
-
- STet{RLO}{PDF}
-
- which will result because we bump up the embedding level as
- soon as we see the RLO and pop it as soon as we see the PDF,
- so RLO itself has the same embedding level as "teST", and
- thus would be normally delivered last, just before the PDF.
- The switch below fiddles with the level of PDF so that this
- ugly side effect does not happen.
+ /* Update the cache, but only if this state was already cached. */
+ bidi_cache_iterator_state (bidi_it, 1, 1);
- (This is, of course, only important if the formatting codes
- are actually displayed, but Emacs does need to display them
- if the user wants to.) */
- level = prev_level;
- }
- else if (bidi_it->orig_type == NEUTRAL_B /* L1 */
+ /* Resolve implicit levels. */
+ if (bidi_it->orig_type == NEUTRAL_B /* L1 */
|| bidi_it->orig_type == NEUTRAL_S
|| bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB
|| (bidi_it->orig_type == NEUTRAL_WS
if (end_flag)
emacs_abort ();
- bidi_cache_iterator_state (bidi_it, 1);
+ if (!bidi_cache_iterator_state (bidi_it, 1, 0))
+ {
+ /* Can't happen: if the cache needs to grow, it means we
+ were at base embedding level, so the cache should have
+ been either empty or already large enough to cover this
+ character position. */
+ emacs_abort ();
+ }
do {
new_level = bidi_level_of_next_char (bidi_it);
- bidi_cache_iterator_state (bidi_it, 1);
+ /* If the cache is full, perform an emergency return by
+ pretending that the level ended. */
+ if (!bidi_cache_iterator_state (bidi_it, 1, 0))
+ {
+ new_level = level - 1;
+ /* Since the cache should only grow when we are scanning
+ forward looking for the edge of the level that is one
+ above the base embedding level, we can only have this
+ contingency when LEVEL - 1 is the base embedding
+ level. */
+ eassert (new_level == bidi_it->level_stack[0].level);
+ /* Plan B, for when the cache overflows: Back up to the
+ previous character by fetching the last cached state,
+ and force the resolved level of that character be the
+ base embedding level. */
+ bidi_cache_fetch_state (bidi_cache_idx - 1, bidi_it);
+ bidi_it->resolved_level = new_level;
+ bidi_cache_iterator_state (bidi_it, 1, 1);
+ }
} while (new_level >= level);
}
}
sentinel.ch_len = 1;
sentinel.nchars = 1;
}
- bidi_cache_iterator_state (&sentinel, 1);
+ bidi_cache_iterator_state (&sentinel, 1, 0);
}
old_level = bidi_it->resolved_level;
in the cache, which at this point should not happen. If
it does, we will infloop. */
eassert (next_level >= 0);
+ /* If next_level is not consistent with incr, we might
+ infloop. */
+ eassert (incr > 0
+ ? next_level > expected_next_level
+ : next_level < expected_next_level);
expected_next_level += incr;
level_to_search += incr;
bidi_find_other_level_edge (bidi_it, level_to_search, !ascending);
&& bidi_it->charpos > (bidi_cache[bidi_cache_idx - 1].charpos
+ bidi_cache[bidi_cache_idx - 1].nchars - 1))
bidi_cache_reset ();
+ /* Also reset the cache if it overflowed and we have just
+ emergency-exited using Plan B. */
+ else if (bidi_it->resolved_level == bidi_it->level_stack[0].level
+ && bidi_cache_idx >= bidi_cache_size
+ && bidi_it->charpos == bidi_cache[bidi_cache_idx - 1].charpos)
+ bidi_cache_reset ();
/* But as long as we are caching during forward scan, we must
cache each state, or else the cache integrity will be
compromised: it assumes cached states correspond to buffer
positions 1:1. */
else
- bidi_cache_iterator_state (bidi_it, 1);
+ bidi_cache_iterator_state (bidi_it, 1, 0);
}
+ eassert (bidi_it->resolved_level >= 0
+ && bidi_it->resolved_level <= BIDI_MAXDEPTH + 2);
+
if (STRINGP (bidi_it->string.lstring))
UNGCPRO;
}
+/* Utility function for looking for strong directional characters
+ whose bidi type was overridden by a directional override. */
+ptrdiff_t
+bidi_find_first_overridden (struct bidi_it *bidi_it)
+{
+ ptrdiff_t found_pos = ZV;
+
+ do
+ {
+ /* Need to call bidi_resolve_weak, not bidi_resolve_explicit,
+ because the directional overrides are applied by the
+ former. */
+ bidi_type_t type = bidi_resolve_weak (bidi_it);
+
+ if ((type == STRONG_R && bidi_it->orig_type == STRONG_L)
+ || (type == STRONG_L
+ && (bidi_it->orig_type == STRONG_R
+ || bidi_it->orig_type == STRONG_AL)))
+ found_pos = bidi_it->charpos;
+ } while (found_pos == ZV
+ && bidi_it->charpos < ZV
+ && bidi_it->ch != BIDI_EOB
+ && bidi_it->ch != '\n');
+
+ return found_pos;
+}
+
/* This is meant to be called from within the debugger, whenever you
wish to examine the cache contents. */
void bidi_dump_cached_states (void) EXTERNALLY_VISIBLE;