void DDGifSlurp(GifInfo *info, bool shouldDecode) {
GifRecordType RecordType;
GifByteType *ExtData;
int codeSize;
int ExtFunction;
do {
if (DGifGetRecordType(info->gifFilePtr, &RecordType) == GIF_ERROR)
return;
switch (RecordType) {
case IMAGE_DESC_RECORD_TYPE:
if (DGifGetImageDesc(info->gifFilePtr, !shouldDecode) == GIF_ERROR)
return;
const uint_fast16_t requiredScreenWidth = info->gifFilePtr->Image.Left + info->gifFilePtr->Image.Width;
const uint_fast16_t requiredScreenHeight = info->gifFilePtr->Image.Top + info->gifFilePtr->Image.Height;
if (requiredScreenWidth > info->gifFilePtr->SWidth || requiredScreenHeight > info->gifFilePtr->SHeight) {
if (shouldDecode) {
void *tmpRasterBits = realloc(info->rasterBits,
requiredScreenWidth * requiredScreenHeight * sizeof(GifPixelType));
if (tmpRasterBits == NULL) {
info->gifFilePtr->Error = D_GIF_ERR_NOT_ENOUGH_MEM;
return;
}
info->rasterBits = tmpRasterBits;
}
else {
info->gifFilePtr->SWidth = requiredScreenWidth;
info->gifFilePtr->SHeight = requiredScreenHeight;
}
}
if (shouldDecode) {
if (info->gifFilePtr->Image.Interlace) {
uint_fast16_t i, j;
/*
* The way an interlaced image should be read -
* offsets and jumps...
*/
uint_fast8_t InterlacedOffset[] = {0, 4, 2, 1};
uint_fast8_t InterlacedJumps[] = {8, 8, 4, 2};
/* Need to perform 4 passes on the image */
for (i = 0; i < 4; i++)
for (j = InterlacedOffset[i]; j < info->gifFilePtr->Image.Height; j += InterlacedJumps[i]) {
if (DGifGetLine(info->gifFilePtr, info->rasterBits + j * info->gifFilePtr->Image.Width,
info->gifFilePtr->Image.Width) == GIF_ERROR)
return;
}
}
else {
if (DGifGetLine(
info->gifFilePtr, info->rasterBits,
info->gifFilePtr->Image.Width * info->gifFilePtr->Image.Height) == GIF_ERROR)
return;
}
return;
}
else {
if (DGifGetCode(info->gifFilePtr, &codeSize, &ExtData) == GIF_ERROR)
return;
while (ExtData != NULL) {
if (DGifGetCodeNext(info->gifFilePtr, &ExtData) == GIF_ERROR)
return;
}
}
break;
case EXTENSION_RECORD_TYPE:
if (DGifGetExtension(info->gifFilePtr, &ExtFunction, &ExtData) == GIF_ERROR)
return;
if (!shouldDecode) {
GraphicsControlBlock *tmpInfos = realloc(info->controlBlock,
(info->gifFilePtr->ImageCount + 1) *
sizeof(GraphicsControlBlock));
if (tmpInfos == NULL) {
info->gifFilePtr->Error = D_GIF_ERR_NOT_ENOUGH_MEM;
return;
}
info->controlBlock = tmpInfos;
info->controlBlock[info->gifFilePtr->ImageCount].DelayTime = DEFAULT_FRAME_DURATION_MS;
if (readExtensions(ExtFunction, ExtData, info) == GIF_ERROR)
return;
}
while (ExtData != NULL) {
if (DGifGetExtensionNext(info->gifFilePtr, &ExtData,
&ExtFunction) == GIF_ERROR)
return;
if (!shouldDecode) {
if (readExtensions(ExtFunction, ExtData, info) == GIF_ERROR)
return;
}
}
break;
case TERMINATE_RECORD_TYPE:
break;
default: /* Should be trapped by DGifGetRecordType */
break;
}
} while (RecordType != TERMINATE_RECORD_TYPE);
info->rewindFunction(info);
}
void DDGifSlurp(GifInfo *info, bool decode, bool exitAfterFrame) {
GifRecordType RecordType;
GifByteType *ExtData;
int ExtFunction;
GifFileType *gifFilePtr;
gifFilePtr = info->gifFilePtr;
uint_fast32_t lastAllocatedGCBIndex = 0;
do {
if (DGifGetRecordType(gifFilePtr, &RecordType) == GIF_ERROR)
return;
bool isInitialPass = !decode && !exitAfterFrame;
switch (RecordType) {
case IMAGE_DESC_RECORD_TYPE:
if (DGifGetImageDesc(gifFilePtr, isInitialPass) == GIF_ERROR)
return;
if (isInitialPass) {
int_fast32_t widthOverflow = gifFilePtr->Image.Width - gifFilePtr->SWidth;
int_fast32_t heightOverflow = gifFilePtr->Image.Height - gifFilePtr->SHeight;
if (widthOverflow > 0 || heightOverflow > 0) {
gifFilePtr->SWidth += widthOverflow;
gifFilePtr->SHeight += heightOverflow;
}
SavedImage *sp = &gifFilePtr->SavedImages[gifFilePtr->ImageCount - 1];
int_fast32_t topOverflow = gifFilePtr->Image.Top + gifFilePtr->Image.Height - gifFilePtr->SHeight;
if (topOverflow > 0) {
sp->ImageDesc.Top -= topOverflow;
}
int_fast32_t leftOverflow = gifFilePtr->Image.Left + gifFilePtr->Image.Width - gifFilePtr->SWidth;
if (leftOverflow > 0) {
sp->ImageDesc.Left -= leftOverflow;
}
if (!updateGCB(info, &lastAllocatedGCBIndex)) {
return;
}
}
if (decode) {
int_fast32_t widthOverflow = gifFilePtr->Image.Width - info->originalWidth;
int_fast32_t heightOverflow = gifFilePtr->Image.Height - info->originalHeight;
if (widthOverflow > 0 || heightOverflow > 0) {
void *tmpRasterBits = reallocarray(info->rasterBits, info->originalWidth * info->originalHeight, sizeof(GifPixelType));
if (tmpRasterBits == NULL) {
gifFilePtr->Error = D_GIF_ERR_NOT_ENOUGH_MEM;
return;
}
info->rasterBits = tmpRasterBits;
}
if (gifFilePtr->Image.Interlace) {
uint_fast16_t i, j;
/*
* The way an interlaced image should be read -
* offsets and jumps...
*/
uint_fast8_t InterlacedOffset[] = {0, 4, 2, 1};
uint_fast8_t InterlacedJumps[] = {8, 8, 4, 2};
/* Need to perform 4 passes on the image */
for (i = 0; i < 4; i++)
for (j = InterlacedOffset[i]; j < gifFilePtr->Image.Height; j += InterlacedJumps[i]) {
if (DGifGetLine(gifFilePtr, info->rasterBits + j * gifFilePtr->Image.Width, gifFilePtr->Image.Width) == GIF_ERROR)
return;
}
} else {
if (DGifGetLine(gifFilePtr, info->rasterBits, gifFilePtr->Image.Width * gifFilePtr->Image.Height) == GIF_ERROR) {
return;
}
}
if (info->sampleSize > 1) {
unsigned char *dst = info->rasterBits;
unsigned char *src = info->rasterBits;
unsigned char *const srcEndImage = info->rasterBits + gifFilePtr->Image.Width * gifFilePtr->Image.Height;
do {
unsigned char *srcNextLineStart = src + gifFilePtr->Image.Width * info->sampleSize;
unsigned char *const srcEndLine = src + gifFilePtr->Image.Width;
unsigned char *dstEndLine = dst + gifFilePtr->Image.Width / info->sampleSize;
do {
*dst = *src;
dst++;
src += info->sampleSize;
} while (src < srcEndLine);
dst = dstEndLine;
src = srcNextLineStart;
} while (src < srcEndImage);
}
return;
} else {
do {
if (DGifGetCodeNext(gifFilePtr, &ExtData) == GIF_ERROR) {
return;
}
} while (ExtData != NULL);
if (exitAfterFrame) {
return;
}
}
break;
case EXTENSION_RECORD_TYPE:
if (DGifGetExtension(gifFilePtr, &ExtFunction, &ExtData) == GIF_ERROR) {
return;
}
if (isInitialPass) {
updateGCB(info, &lastAllocatedGCBIndex);
if (readExtensions(ExtFunction, ExtData, info) == GIF_ERROR) {
return;
}
}
while (ExtData != NULL) {
if (DGifGetExtensionNext(gifFilePtr, &ExtData) == GIF_ERROR) {
return;
}
if (isInitialPass) {
if (readExtensions(ExtFunction, ExtData, info) == GIF_ERROR)
return;
}
}
break;
case TERMINATE_RECORD_TYPE:
break;
default: /* Should be trapped by DGifGetRecordType */
break;
}
} while (RecordType != TERMINATE_RECORD_TYPE);
info->rewindFunction(info);
}
