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authorVincent Sanders <vince@kyllikki.org>2017-01-25 00:32:35 (GMT)
committer Vincent Sanders <vince@kyllikki.org>2017-01-25 00:32:35 (GMT)
commita5ff5ae14c6aff6398187c22e92c2136b9861f2e (patch)
tree9a95b3e86f01f322fa18d7646bdd7d69eeb2309f
parent33981c486fc6b660ee1ad8c48a38b2028c2b716e (diff)
downloadlibnsgif-a5ff5ae14c6aff6398187c22e92c2136b9861f2e.tar.gz
libnsgif-a5ff5ae14c6aff6398187c22e92c2136b9861f2e.tar.bz2
remove global clear_image flag and pass values instead
-rw-r--r--src/libnsgif.c462
1 files changed, 239 insertions, 223 deletions
diff --git a/src/libnsgif.c b/src/libnsgif.c
index 69c54ea..081ea9f 100644
--- a/src/libnsgif.c
+++ b/src/libnsgif.c
@@ -95,8 +95,6 @@ static int firstcode, oldcode;
static bool zero_data_block = false;
static bool get_done;
-/* Whether to clear the decoded image rather than plot */
-static bool clear_image = false;
/**
@@ -772,223 +770,17 @@ static int gif_next_code(gif_animation *gif, int code_size)
}
-/* exported function documented in libnsgif.h */
-void gif_create(gif_animation *gif, gif_bitmap_callback_vt *bitmap_callbacks)
-{
- memset(gif, 0, sizeof(gif_animation));
- gif->bitmap_callbacks = *bitmap_callbacks;
- gif->decoded_frame = GIF_INVALID_FRAME;
-}
-
-
-/* exported function documented in libnsgif.h */
-gif_result gif_initialise(gif_animation *gif, size_t size, unsigned char *data)
-{
- unsigned char *gif_data;
- unsigned int index;
- gif_result return_value;
-
- /* Initialize values */
- gif->buffer_size = size;
- gif->gif_data = data;
-
- /* Check for sufficient data to be a GIF (6-byte header + 7-byte
- * logical screen descriptor)
- */
- if (gif->buffer_size < 13) {
- return GIF_INSUFFICIENT_DATA;
- }
-
- /* Get our current processing position */
- gif_data = gif->gif_data + gif->buffer_position;
-
- /* See if we should initialise the GIF */
- if (gif->buffer_position == 0) {
- /* We want everything to be NULL before we start so we've no
- * chance of freeing bad pointers (paranoia)
- */
- gif->frame_image = NULL;
- gif->frames = NULL;
- gif->local_colour_table = NULL;
- gif->global_colour_table = NULL;
-
- /* The caller may have been lazy and not reset any values */
- gif->frame_count = 0;
- gif->frame_count_partial = 0;
- gif->decoded_frame = GIF_INVALID_FRAME;
-
- /* 6-byte GIF file header is:
- *
- * +0 3CHARS Signature ('GIF')
- * +3 3CHARS Version ('87a' or '89a')
- */
- if (strncmp((const char *) gif_data, "GIF", 3) != 0) {
- return GIF_DATA_ERROR;
- }
- gif_data += 3;
-
- /* Ensure GIF reports version 87a or 89a */
- /*
- if ((strncmp(gif_data, "87a", 3) != 0) &&
- (strncmp(gif_data, "89a", 3) != 0))
- LOG(("Unknown GIF format - proceeding anyway"));
- */
- gif_data += 3;
-
- /* 7-byte Logical Screen Descriptor is:
- *
- * +0 SHORT Logical Screen Width
- * +2 SHORT Logical Screen Height
- * +4 CHAR __Packed Fields__
- * 1BIT Global Colour Table Flag
- * 3BITS Colour Resolution
- * 1BIT Sort Flag
- * 3BITS Size of Global Colour Table
- * +5 CHAR Background Colour Index
- * +6 CHAR Pixel Aspect Ratio
- */
- gif->width = gif_data[0] | (gif_data[1] << 8);
- gif->height = gif_data[2] | (gif_data[3] << 8);
- gif->global_colours = (gif_data[4] & GIF_COLOUR_TABLE_MASK);
- gif->colour_table_size = (2 << (gif_data[4] & GIF_COLOUR_TABLE_SIZE_MASK));
- gif->background_index = gif_data[5];
- gif->aspect_ratio = gif_data[6];
- gif->loop_count = 1;
- gif_data += 7;
-
- /* Some broken GIFs report the size as the screen size they
- * were created in. As such, we detect for the common cases and
- * set the sizes as 0 if they are found which results in the
- * GIF being the maximum size of the frames.
- */
- if (((gif->width == 640) && (gif->height == 480)) ||
- ((gif->width == 640) && (gif->height == 512)) ||
- ((gif->width == 800) && (gif->height == 600)) ||
- ((gif->width == 1024) && (gif->height == 768)) ||
- ((gif->width == 1280) && (gif->height == 1024)) ||
- ((gif->width == 1600) && (gif->height == 1200)) ||
- ((gif->width == 0) || (gif->height == 0)) ||
- ((gif->width > 2048) || (gif->height > 2048))) {
- gif->width = 1;
- gif->height = 1;
- }
-
- /* Allocate some data irrespective of whether we've got any
- * colour tables. We always get the maximum size in case a GIF
- * is lying to us. It's far better to give the wrong colours
- * than to trample over some memory somewhere.
- */
- gif->global_colour_table = calloc(GIF_MAX_COLOURS, sizeof(unsigned int));
- gif->local_colour_table = calloc(GIF_MAX_COLOURS, sizeof(unsigned int));
- if ((gif->global_colour_table == NULL) ||
- (gif->local_colour_table == NULL)) {
- gif_finalise(gif);
- return GIF_INSUFFICIENT_MEMORY;
- }
-
- /* Set the first colour to a value that will never occur in
- * reality so we know if we've processed it
- */
- gif->global_colour_table[0] = GIF_PROCESS_COLOURS;
-
- /* Check if the GIF has no frame data (13-byte header + 1-byte
- * termination block) Although generally useless, the GIF
- * specification does not expressly prohibit this
- */
- if (gif->buffer_size == 14) {
- if (gif_data[0] == GIF_TRAILER) {
- return GIF_OK;
- } else {
- return GIF_INSUFFICIENT_DATA;
- }
- }
-
- /* Initialise enough workspace for 4 frames initially */
- if ((gif->frames = (gif_frame *)malloc(sizeof(gif_frame))) == NULL) {
- gif_finalise(gif);
- return GIF_INSUFFICIENT_MEMORY;
- }
- gif->frame_holders = 1;
-
- /* Initialise the bitmap header */
- assert(gif->bitmap_callbacks.bitmap_create);
- gif->frame_image = gif->bitmap_callbacks.bitmap_create(gif->width, gif->height);
- if (gif->frame_image == NULL) {
- gif_finalise(gif);
- return GIF_INSUFFICIENT_MEMORY;
- }
-
- /* Remember we've done this now */
- gif->buffer_position = gif_data - gif->gif_data;
- }
-
- /* Do the colour map if we haven't already. As the top byte is always
- * 0xff or 0x00 depending on the transparency we know if it's been
- * filled in.
- */
- if (gif->global_colour_table[0] == GIF_PROCESS_COLOURS) {
- /* Check for a global colour map signified by bit 7 */
- if (gif->global_colours) {
- if (gif->buffer_size < (gif->colour_table_size * 3 + 12)) {
- return GIF_INSUFFICIENT_DATA;
- }
- for (index = 0; index < gif->colour_table_size; index++) {
- /* Gif colour map contents are r,g,b.
- *
- * We want to pack them bytewise into the
- * colour table, such that the red component
- * is in byte 0 and the alpha component is in
- * byte 3.
- */
- unsigned char *entry = (unsigned char *) &gif->
- global_colour_table[index];
-
- entry[0] = gif_data[0]; /* r */
- entry[1] = gif_data[1]; /* g */
- entry[2] = gif_data[2]; /* b */
- entry[3] = 0xff; /* a */
-
- gif_data += 3;
- }
- gif->buffer_position = (gif_data - gif->gif_data);
- } else {
- /* Create a default colour table with the first two
- * colours as black and white
- */
- unsigned int *entry = gif->global_colour_table;
-
- entry[0] = 0x00000000;
- /* Force Alpha channel to opaque */
- ((unsigned char *) entry)[3] = 0xff;
-
- entry[1] = 0xffffffff;
- }
- }
-
- /* Repeatedly try to initialise frames */
- while ((return_value = gif_initialise_frame(gif)) == GIF_WORKING);
-
- /* If there was a memory error tell the caller */
- if ((return_value == GIF_INSUFFICIENT_MEMORY) ||
- (return_value == GIF_DATA_ERROR)) {
- return return_value;
- }
-
- /* If we didn't have some frames then a GIF_INSUFFICIENT_DATA becomes a
- * GIF_INSUFFICIENT_FRAME_DATA
- */
- if ((return_value == GIF_INSUFFICIENT_DATA) &&
- (gif->frame_count_partial > 0)) {
- return GIF_INSUFFICIENT_FRAME_DATA;
- }
-
- /* Return how many we got */
- return return_value;
-}
-
-
-/* exported function documented in libnsgif.h */
-gif_result gif_decode_frame(gif_animation *gif, unsigned int frame)
+/**
+ * decode a gif frame
+ *
+ * \param gif gif animation context.
+ * \param frame The frame number to decode.
+ * \param clear_image flag for image data being cleared instead of plotted.
+ */
+static gif_result
+gif_internal_decode_frame(gif_animation *gif,
+ unsigned int frame,
+ bool clear_image)
{
unsigned int index = 0;
unsigned char *gif_data, *gif_end;
@@ -1182,11 +974,12 @@ gif_result gif_decode_frame(gif_animation *gif, unsigned int frame)
/* memset((char*)frame_data, colour_table[gif->background_index], gif->width * gif->height * sizeof(int)); */
} else if ((frame != 0) &&
(gif->frames[frame - 1].disposal_method == GIF_FRAME_CLEAR)) {
- clear_image = true;
- if ((return_value = gif_decode_frame(gif, (frame - 1))) != GIF_OK) {
+ return_value = gif_internal_decode_frame(gif,
+ (frame - 1),
+ true);
+ if (return_value != GIF_OK) {
goto gif_decode_frame_exit;
}
- clear_image = false;
/*
* If the previous frame's disposal method requires we
* restore the previous image, find the last image set
@@ -1205,7 +998,8 @@ gif_result gif_decode_frame(gif_animation *gif, unsigned int frame)
GIF_TRANSPARENT_COLOUR,
gif->width * gif->height * sizeof(int));
} else {
- if ((return_value = gif_decode_frame(gif, last_undisposed_frame)) != GIF_OK) {
+ return_value = gif_internal_decode_frame(gif, last_undisposed_frame, false);
+ if (return_value != GIF_OK) {
goto gif_decode_frame_exit;
}
/* Get this frame's data */
@@ -1322,6 +1116,228 @@ gif_decode_frame_exit:
/* exported function documented in libnsgif.h */
+void gif_create(gif_animation *gif, gif_bitmap_callback_vt *bitmap_callbacks)
+{
+ memset(gif, 0, sizeof(gif_animation));
+ gif->bitmap_callbacks = *bitmap_callbacks;
+ gif->decoded_frame = GIF_INVALID_FRAME;
+}
+
+
+/* exported function documented in libnsgif.h */
+gif_result gif_initialise(gif_animation *gif, size_t size, unsigned char *data)
+{
+ unsigned char *gif_data;
+ unsigned int index;
+ gif_result return_value;
+
+ /* Initialize values */
+ gif->buffer_size = size;
+ gif->gif_data = data;
+
+ /* Check for sufficient data to be a GIF (6-byte header + 7-byte
+ * logical screen descriptor)
+ */
+ if (gif->buffer_size < 13) {
+ return GIF_INSUFFICIENT_DATA;
+ }
+
+ /* Get our current processing position */
+ gif_data = gif->gif_data + gif->buffer_position;
+
+ /* See if we should initialise the GIF */
+ if (gif->buffer_position == 0) {
+ /* We want everything to be NULL before we start so we've no
+ * chance of freeing bad pointers (paranoia)
+ */
+ gif->frame_image = NULL;
+ gif->frames = NULL;
+ gif->local_colour_table = NULL;
+ gif->global_colour_table = NULL;
+
+ /* The caller may have been lazy and not reset any values */
+ gif->frame_count = 0;
+ gif->frame_count_partial = 0;
+ gif->decoded_frame = GIF_INVALID_FRAME;
+
+ /* 6-byte GIF file header is:
+ *
+ * +0 3CHARS Signature ('GIF')
+ * +3 3CHARS Version ('87a' or '89a')
+ */
+ if (strncmp((const char *) gif_data, "GIF", 3) != 0) {
+ return GIF_DATA_ERROR;
+ }
+ gif_data += 3;
+
+ /* Ensure GIF reports version 87a or 89a */
+ /*
+ if ((strncmp(gif_data, "87a", 3) != 0) &&
+ (strncmp(gif_data, "89a", 3) != 0))
+ LOG(("Unknown GIF format - proceeding anyway"));
+ */
+ gif_data += 3;
+
+ /* 7-byte Logical Screen Descriptor is:
+ *
+ * +0 SHORT Logical Screen Width
+ * +2 SHORT Logical Screen Height
+ * +4 CHAR __Packed Fields__
+ * 1BIT Global Colour Table Flag
+ * 3BITS Colour Resolution
+ * 1BIT Sort Flag
+ * 3BITS Size of Global Colour Table
+ * +5 CHAR Background Colour Index
+ * +6 CHAR Pixel Aspect Ratio
+ */
+ gif->width = gif_data[0] | (gif_data[1] << 8);
+ gif->height = gif_data[2] | (gif_data[3] << 8);
+ gif->global_colours = (gif_data[4] & GIF_COLOUR_TABLE_MASK);
+ gif->colour_table_size = (2 << (gif_data[4] & GIF_COLOUR_TABLE_SIZE_MASK));
+ gif->background_index = gif_data[5];
+ gif->aspect_ratio = gif_data[6];
+ gif->loop_count = 1;
+ gif_data += 7;
+
+ /* Some broken GIFs report the size as the screen size they
+ * were created in. As such, we detect for the common cases and
+ * set the sizes as 0 if they are found which results in the
+ * GIF being the maximum size of the frames.
+ */
+ if (((gif->width == 640) && (gif->height == 480)) ||
+ ((gif->width == 640) && (gif->height == 512)) ||
+ ((gif->width == 800) && (gif->height == 600)) ||
+ ((gif->width == 1024) && (gif->height == 768)) ||
+ ((gif->width == 1280) && (gif->height == 1024)) ||
+ ((gif->width == 1600) && (gif->height == 1200)) ||
+ ((gif->width == 0) || (gif->height == 0)) ||
+ ((gif->width > 2048) || (gif->height > 2048))) {
+ gif->width = 1;
+ gif->height = 1;
+ }
+
+ /* Allocate some data irrespective of whether we've got any
+ * colour tables. We always get the maximum size in case a GIF
+ * is lying to us. It's far better to give the wrong colours
+ * than to trample over some memory somewhere.
+ */
+ gif->global_colour_table = calloc(GIF_MAX_COLOURS, sizeof(unsigned int));
+ gif->local_colour_table = calloc(GIF_MAX_COLOURS, sizeof(unsigned int));
+ if ((gif->global_colour_table == NULL) ||
+ (gif->local_colour_table == NULL)) {
+ gif_finalise(gif);
+ return GIF_INSUFFICIENT_MEMORY;
+ }
+
+ /* Set the first colour to a value that will never occur in
+ * reality so we know if we've processed it
+ */
+ gif->global_colour_table[0] = GIF_PROCESS_COLOURS;
+
+ /* Check if the GIF has no frame data (13-byte header + 1-byte
+ * termination block) Although generally useless, the GIF
+ * specification does not expressly prohibit this
+ */
+ if (gif->buffer_size == 14) {
+ if (gif_data[0] == GIF_TRAILER) {
+ return GIF_OK;
+ } else {
+ return GIF_INSUFFICIENT_DATA;
+ }
+ }
+
+ /* Initialise enough workspace for 4 frames initially */
+ if ((gif->frames = (gif_frame *)malloc(sizeof(gif_frame))) == NULL) {
+ gif_finalise(gif);
+ return GIF_INSUFFICIENT_MEMORY;
+ }
+ gif->frame_holders = 1;
+
+ /* Initialise the bitmap header */
+ assert(gif->bitmap_callbacks.bitmap_create);
+ gif->frame_image = gif->bitmap_callbacks.bitmap_create(gif->width, gif->height);
+ if (gif->frame_image == NULL) {
+ gif_finalise(gif);
+ return GIF_INSUFFICIENT_MEMORY;
+ }
+
+ /* Remember we've done this now */
+ gif->buffer_position = gif_data - gif->gif_data;
+ }
+
+ /* Do the colour map if we haven't already. As the top byte is always
+ * 0xff or 0x00 depending on the transparency we know if it's been
+ * filled in.
+ */
+ if (gif->global_colour_table[0] == GIF_PROCESS_COLOURS) {
+ /* Check for a global colour map signified by bit 7 */
+ if (gif->global_colours) {
+ if (gif->buffer_size < (gif->colour_table_size * 3 + 12)) {
+ return GIF_INSUFFICIENT_DATA;
+ }
+ for (index = 0; index < gif->colour_table_size; index++) {
+ /* Gif colour map contents are r,g,b.
+ *
+ * We want to pack them bytewise into the
+ * colour table, such that the red component
+ * is in byte 0 and the alpha component is in
+ * byte 3.
+ */
+ unsigned char *entry = (unsigned char *) &gif->
+ global_colour_table[index];
+
+ entry[0] = gif_data[0]; /* r */
+ entry[1] = gif_data[1]; /* g */
+ entry[2] = gif_data[2]; /* b */
+ entry[3] = 0xff; /* a */
+
+ gif_data += 3;
+ }
+ gif->buffer_position = (gif_data - gif->gif_data);
+ } else {
+ /* Create a default colour table with the first two
+ * colours as black and white
+ */
+ unsigned int *entry = gif->global_colour_table;
+
+ entry[0] = 0x00000000;
+ /* Force Alpha channel to opaque */
+ ((unsigned char *) entry)[3] = 0xff;
+
+ entry[1] = 0xffffffff;
+ }
+ }
+
+ /* Repeatedly try to initialise frames */
+ while ((return_value = gif_initialise_frame(gif)) == GIF_WORKING);
+
+ /* If there was a memory error tell the caller */
+ if ((return_value == GIF_INSUFFICIENT_MEMORY) ||
+ (return_value == GIF_DATA_ERROR)) {
+ return return_value;
+ }
+
+ /* If we didn't have some frames then a GIF_INSUFFICIENT_DATA becomes a
+ * GIF_INSUFFICIENT_FRAME_DATA
+ */
+ if ((return_value == GIF_INSUFFICIENT_DATA) &&
+ (gif->frame_count_partial > 0)) {
+ return GIF_INSUFFICIENT_FRAME_DATA;
+ }
+
+ /* Return how many we got */
+ return return_value;
+}
+
+
+/* exported function documented in libnsgif.h */
+gif_result gif_decode_frame(gif_animation *gif, unsigned int frame)
+{
+ return gif_internal_decode_frame(gif, frame, false);
+}
+
+
+/* exported function documented in libnsgif.h */
void gif_finalise(gif_animation *gif)
{
/* Release all our memory blocks */