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authorVincent Sanders <vince@kyllikki.org>2016-08-19 19:48:54 (GMT)
committer Vincent Sanders <vince@kyllikki.org>2016-08-19 19:48:54 (GMT)
commit135c1700bfeff8d69ed2fb8c181f75c422a7d887 (patch)
treeabb47de18fef51d94be032fd5fc683032c3f5e9d
parent8cdf3858127bbe1a23bd68546ddcb5b350a03904 (diff)
downloadlibnsbmp-135c1700bfeff8d69ed2fb8c181f75c422a7d887.tar.gz
libnsbmp-135c1700bfeff8d69ed2fb8c181f75c422a7d887.tar.bz2
separate 24bpp decoder from 32bpp
-rw-r--r--src/libnsbmp.c127
1 files changed, 110 insertions, 17 deletions
diff --git a/src/libnsbmp.c b/src/libnsbmp.c
index b4747f6..7318347 100644
--- a/src/libnsbmp.c
+++ b/src/libnsbmp.c
@@ -483,7 +483,7 @@ static bmp_result ico_header_parse(ico_collection *ico, uint8_t *data)
/**
- * Decode BMP data stored in 24bpp colour.
+ * Decode BMP data stored in 32bpp colour.
*
* \param bmp the BMP image to decode
* \param start the data to decode, updated to last byte read on success
@@ -492,16 +492,18 @@ static bmp_result ico_header_parse(ico_collection *ico, uint8_t *data)
* BMP_INSUFFICIENT_DATA if the bitmap data ends unexpectedly;
* in this case, the image may be partially viewable
*/
-static bmp_result bmp_decode_rgb24(bmp_image *bmp, uint8_t **start, int bytes)
+static bmp_result bmp_decode_rgb32(bmp_image *bmp, uint8_t **start, int bytes)
{
uint8_t *top, *bottom, *end, *data;
uint32_t *scanline;
uint32_t x, y;
- uint32_t swidth, skip;
+ uint32_t swidth;
intptr_t addr;
uint8_t i;
uint32_t word;
+ assert(bmp->bpp == 32);
+
data = *start;
swidth = bmp->bitmap_callbacks.bitmap_get_bpp(bmp->bitmap) * bmp->width;
top = bmp->bitmap_callbacks.bitmap_get_buffer(bmp->bitmap);
@@ -510,12 +512,11 @@ static bmp_result bmp_decode_rgb24(bmp_image *bmp, uint8_t **start, int bytes)
bottom = top + (uint64_t)swidth * (bmp->height - 1);
end = data + bytes;
addr = ((intptr_t)data) & 3;
- skip = bmp->bpp >> 3;
bmp->decoded = true;
/* Determine transparent index */
if (bmp->limited_trans) {
- if ((data + skip) > end)
+ if ((data + 4) > end)
return BMP_INSUFFICIENT_DATA;
if (bmp->encoding == BMP_ENCODING_BITFIELDS)
bmp->transparent_index = read_uint32(data, 0);
@@ -526,7 +527,7 @@ static bmp_result bmp_decode_rgb24(bmp_image *bmp, uint8_t **start, int bytes)
for (y = 0; y < bmp->height; y++) {
while (addr != (((intptr_t)data) & 3))
data++;
- if ((data + (skip * bmp->width)) > end)
+ if ((data + (4 * bmp->width)) > end)
return BMP_INSUFFICIENT_DATA;
if (bmp->reversed)
scanline = (void *)(top + (y * swidth));
@@ -543,17 +544,19 @@ static bmp_result bmp_decode_rgb24(bmp_image *bmp, uint8_t **start, int bytes)
/* 32-bit BMPs have alpha masks, but sometimes they're not utilized */
if (bmp->opaque)
scanline[x] |= (0xff << 24);
- data += skip;
+ data += 4;
scanline[x] = read_uint32((uint8_t *)&scanline[x],0);
}
} else {
for (x = 0; x < bmp->width; x++) {
scanline[x] = data[2] | (data[1] << 8) | (data[0] << 16);
- if ((bmp->limited_trans) && (scanline[x] == bmp->transparent_index))
+ if ((bmp->limited_trans) && (scanline[x] == bmp->transparent_index)) {
scanline[x] = bmp->trans_colour;
- if (bmp->opaque)
+ }
+ if (bmp->opaque) {
scanline[x] |= (0xff << 24);
- data += skip;
+ }
+ data += 4;
scanline[x] = read_uint32((uint8_t *)&scanline[x],0);
}
}
@@ -564,6 +567,80 @@ static bmp_result bmp_decode_rgb24(bmp_image *bmp, uint8_t **start, int bytes)
/**
+ * Decode BMP data stored in 24bpp colour.
+ *
+ * \param bmp the BMP image to decode
+ * \param start the data to decode, updated to last byte read on success
+ * \param bytes the number of bytes of data available
+ * \return BMP_OK on success
+ * BMP_INSUFFICIENT_DATA if the bitmap data ends unexpectedly;
+ * in this case, the image may be partially viewable
+ */
+static bmp_result bmp_decode_rgb24(bmp_image *bmp, uint8_t **start, int bytes)
+{
+ uint8_t *top, *bottom, *end, *data;
+ uint32_t *scanline;
+ uint32_t x, y;
+ uint32_t swidth;
+ intptr_t addr;
+
+ assert(bmp->encoding == BMP_ENCODING_RGB);
+ assert(bmp->bpp == 24);
+
+ data = *start;
+ swidth = bmp->bitmap_callbacks.bitmap_get_bpp(bmp->bitmap) * bmp->width;
+ top = bmp->bitmap_callbacks.bitmap_get_buffer(bmp->bitmap);
+ if (!top) {
+ return BMP_INSUFFICIENT_MEMORY;
+ }
+
+ bottom = top + (uint64_t)swidth * (bmp->height - 1);
+ end = data + bytes;
+ addr = ((intptr_t)data) & 3;
+ bmp->decoded = true;
+
+ /* Determine transparent index */
+ if (bmp->limited_trans) {
+ if ((data + 3) > end) {
+ return BMP_INSUFFICIENT_DATA;
+ }
+
+ bmp->transparent_index = data[2] | (data[1] << 8) | (data[0] << 16);
+ }
+
+ for (y = 0; y < bmp->height; y++) {
+ while (addr != (((intptr_t)data) & 3)) {
+ data++;
+ }
+
+ if ((data + (3 * bmp->width)) > end) {
+ return BMP_INSUFFICIENT_DATA;
+ }
+
+ if (bmp->reversed) {
+ scanline = (void *)(top + (y * swidth));
+ } else {
+ scanline = (void *)(bottom - (y * swidth));
+ }
+
+ for (x = 0; x < bmp->width; x++) {
+ scanline[x] = data[2] | (data[1] << 8) | (data[0] << 16);
+ if ((bmp->limited_trans) && (scanline[x] == bmp->transparent_index)) {
+ scanline[x] = bmp->trans_colour;
+ } else {
+ scanline[x] |= (0xff << 24);
+ }
+ data += 3;
+ scanline[x] = read_uint32((uint8_t *)&scanline[x],0);
+ }
+
+ }
+ *start = data;
+ return BMP_OK;
+}
+
+
+/**
* Decode BMP data stored in 16bpp colour.
*
* \param bmp the BMP image to decode
@@ -1167,12 +1244,22 @@ bmp_result bmp_decode(bmp_image *bmp)
switch (bmp->encoding) {
case BMP_ENCODING_RGB:
- if ((bmp->bpp == 24) || (bmp->bpp == 32)) {
+ switch (bmp->bpp) {
+ case 32:
+ result = bmp_decode_rgb32(bmp, &data, bytes);
+ break;
+
+ case 24:
result = bmp_decode_rgb24(bmp, &data, bytes);
- } else if (bmp->bpp == 16) {
+ break;
+
+ case 16:
result = bmp_decode_rgb16(bmp, &data, bytes);
- } else {
+ break;
+
+ default:
result = bmp_decode_rgb(bmp, &data, bytes);
+ break;
}
break;
@@ -1185,12 +1272,18 @@ bmp_result bmp_decode(bmp_image *bmp)
break;
case BMP_ENCODING_BITFIELDS:
- if (bmp->bpp == 32) {
- result = bmp_decode_rgb24(bmp, &data, bytes);
- } else if (bmp->bpp == 16) {
+ switch (bmp->bpp) {
+ case 32:
+ result = bmp_decode_rgb32(bmp, &data, bytes);
+ break;
+
+ case 16:
result = bmp_decode_rgb16(bmp, &data, bytes);
- } else {
+ break;
+
+ default:
result = BMP_DATA_ERROR;
+ break;
}
break;
}