code.delx.au - pulseaudio/blob - src/pulsecore/strbuf.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2004-2006 Lennart Poettering
   7
   8   PulseAudio is free software; you can redistribute it and/or modify
   9   it under the terms of the GNU Lesser General Public License as published
  10   by the Free Software Foundation; either version 2 of the License,
  11   or (at your option) any later version.
  12
  13   PulseAudio is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with PulseAudio; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21   USA.
  22 ***/
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <sys/types.h>
  29 #include <stdlib.h>
  30 #include <assert.h>
  31 #include <string.h>
  32 #include <stdarg.h>
  33 #include <stdio.h>
  34
  35 #include <pulse/xmalloc.h>
  36
  37 #include "strbuf.h"
  38
  39 /* A chunk of the linked list that makes up the string */
  40 struct chunk {
  41     struct chunk *next;
  42     size_t length;
  43 };
  44
  45 #define CHUNK_TO_TEXT(c) ((char*) (c) + sizeof(struct chunk))
  46
  47 struct pa_strbuf {
  48     size_t length;
  49     struct chunk *head, *tail;
  50 };
  51
  52 pa_strbuf *pa_strbuf_new(void) {
  53     pa_strbuf *sb = pa_xmalloc(sizeof(pa_strbuf));
  54     sb->length = 0;
  55     sb->head = sb->tail = NULL;
  56     return sb;
  57 }
  58
  59 void pa_strbuf_free(pa_strbuf *sb) {
  60     assert(sb);
  61     while (sb->head) {
  62         struct chunk *c = sb->head;
  63         sb->head = sb->head->next;
  64         pa_xfree(c);
  65     }
  66
  67     pa_xfree(sb);
  68 }
  69
  70 /* Make a C string from the string buffer. The caller has to free
  71  * string with pa_xfree(). */
  72 char *pa_strbuf_tostring(pa_strbuf *sb) {
  73     char *t, *e;
  74     struct chunk *c;
  75     assert(sb);
  76
  77     e = t = pa_xmalloc(sb->length+1);
  78
  79     for (c = sb->head; c; c = c->next) {
  80         assert((size_t) (e-t) <= sb->length);
  81         memcpy(e, CHUNK_TO_TEXT(c), c->length);
  82         e += c->length;
  83     }
  84
  85     /* Trailing NUL */
  86     *e = 0;
  87
  88     assert(e == t+sb->length);
  89
  90     return t;
  91 }
  92
  93 /* Combination of pa_strbuf_free() and pa_strbuf_tostring() */
  94 char *pa_strbuf_tostring_free(pa_strbuf *sb) {
  95     char *t;
  96     assert(sb);
  97     t = pa_strbuf_tostring(sb);
  98     pa_strbuf_free(sb);
  99     return t;
 100 }
 101
 102 /* Append a string to the string buffer */
 103 void pa_strbuf_puts(pa_strbuf *sb, const char *t) {
 104     assert(sb && t);
 105     pa_strbuf_putsn(sb, t, strlen(t));
 106 }
 107
 108 /* Append a new chunk to the linked list */
 109 static void append(pa_strbuf *sb, struct chunk *c) {
 110     assert(sb && c);
 111
 112     if (sb->tail) {
 113         assert(sb->head);
 114         sb->tail->next = c;
 115     } else {
 116         assert(!sb->head);
 117         sb->head = c;
 118     }
 119
 120     sb->tail = c;
 121     sb->length += c->length;
 122     c->next = NULL;
 123 }
 124
 125 /* Append up to l bytes of a string to the string buffer */
 126 void pa_strbuf_putsn(pa_strbuf *sb, const char *t, size_t l) {
 127     struct chunk *c;
 128     assert(sb && t);
 129
 130     if (!l)
 131        return;
 132
 133     c = pa_xmalloc(sizeof(struct chunk)+l);
 134     c->length = l;
 135     memcpy(CHUNK_TO_TEXT(c), t, l);
 136
 137     append(sb, c);
 138 }
 139
 140 /* Append a printf() style formatted string to the string buffer. */
 141 /* The following is based on an example from the GNU libc documentation */
 142 int pa_strbuf_printf(pa_strbuf *sb, const char *format, ...) {
 143     int size = 100;
 144     struct chunk *c = NULL;
 145
 146     assert(sb);
 147
 148     for(;;) {
 149         va_list ap;
 150         int r;
 151
 152         c = pa_xrealloc(c, sizeof(struct chunk)+size);
 153
 154         va_start(ap, format);
 155         r = vsnprintf(CHUNK_TO_TEXT(c), size, format, ap);
 156         va_end(ap);
 157
 158         if (r > -1 && r < size) {
 159             c->length = r;
 160             append(sb, c);
 161             return r;
 162         }
 163
 164         if (r > -1)    /* glibc 2.1 */
 165             size = r+1;
 166         else           /* glibc 2.0 */
 167             size *= 2;
 168     }
 169 }