Restructuring and upgrading of LodePNG library.

diff --git a/libeg/lodepng_xtra.c b/libeg/lodepng_xtra.c
new file mode 100644 (file)
index 0000000..2116012
--- /dev/null
+++ b/libeg/lodepng_xtra.c
@@ -0,0 +1,113 @@
+/*
+ * Additional functions to support LodePNG for use in rEFInd
+ *
+ * copyright (c) 2013 by by Roderick W. Smith, and distributed
+ * under the terms of the GNU GPL v3.
+ *
+ * See http://lodev.org/lodepng/ for the original LodePNG.
+ *
+ */
+
+#include "global.h"
+#include "../refind/screen.h"
+#include "lodepng.h"
+
+// EFI's equivalent of realloc requires the original buffer's size as an
+// input parameter, which the standard libc realloc does not require. Thus,
+// I've modified lodepng_malloc() to allocate more memory to store this data,
+// and lodepng_realloc() can then read it when required. Because the size is
+// stored at the start of the allocated area, these functions are NOT
+// interchangeable with the standard EFI functions; memory allocated via
+// lodepng_malloc() should be freed via lodepng_free(), and myfree() should
+// NOT be used with memory allocated via AllocatePool() or AllocateZeroPool()!
+
+void* lodepng_malloc(size_t size) {
+   void *ptr;
+
+   ptr = AllocateZeroPool(size + sizeof(size_t));
+   if (ptr) {
+      *(size_t *) ptr = size;
+      return ((size_t *) ptr) + 1;
+   } else {
+      return NULL;
+   }
+} // void* lodepng_malloc()
+
+void lodepng_free (void *ptr) {
+   if (ptr) {
+      ptr = (void *) (((size_t *) ptr) - 1);
+      FreePool(ptr);
+   }
+} // void lodepng_free()
+
+static size_t report_size(void *ptr) {
+   if (ptr)
+      return * (((size_t *) ptr) - 1);
+   else
+      return 0;
+} // size_t report_size()
+
+void* lodepng_realloc(void *ptr, size_t new_size) {
+   size_t *new_pool;
+   size_t old_size;
+
+   new_pool = lodepng_malloc(new_size);
+   if (new_pool && ptr) {
+      old_size = report_size(ptr);
+      CopyMem(new_pool, ptr, (old_size < new_size) ? old_size : new_size);
+   }
+   return new_pool;
+} // lodepng_realloc()
+
+// Finds length of ASCII string, which MUST be NULL-terminated.
+int MyStrlen(const char *InString) {
+   int Length = 0;
+
+   if (InString) {
+      while (InString[Length] != '\0')
+         Length++;
+   }
+   return Length;
+} // int MyStrlen()
+
+typedef struct _lode_color {
+   UINT8 red;
+   UINT8 green;
+   UINT8 blue;
+   UINT8 alpha;
+} lode_color;
+
+EG_IMAGE * egDecodePNG(IN UINT8 *FileData, IN UINTN FileDataLength, IN UINTN IconSize, IN BOOLEAN WantAlpha) {
+   EG_IMAGE *NewImage = NULL;
+   unsigned Error, Width, Height;
+   EG_PIXEL *PixelData;
+   lode_color *LodeData;
+   UINTN i;
+
+   Error = lodepng_decode_memory((unsigned char **) &PixelData, &Width, &Height, (unsigned char*) FileData,
+                                 (size_t) FileDataLength, LCT_RGBA, 8);
+
+   if (Error) {
+      return NULL;
+   }
+
+   // allocate image structure and buffer
+   NewImage = egCreateImage(Width, Height, WantAlpha);
+   if ((NewImage == NULL) || (NewImage->Width != Width) || (NewImage->Height != Height))
+      return NULL;
+
+   LodeData = (lode_color *) PixelData;
+
+   // Annoyingly, EFI and LodePNG use different ordering of RGB values in
+   // their pixel data representations, so we've got to adjust them....
+   for (i = 0; i < (NewImage->Height * NewImage->Width); i++) {
+      NewImage->PixelData[i].r = LodeData[i].red;
+      NewImage->PixelData[i].g = LodeData[i].green;
+      NewImage->PixelData[i].b = LodeData[i].blue;
+      if (WantAlpha)
+         NewImage->PixelData[i].a = LodeData[i].alpha;
+   }
+   lodepng_free(PixelData);
+
+   return NewImage;
+} // EG_IMAGE * egDecodePNG()
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