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refactor bmp header parser for sharing with stbi_info

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This commit is contained in:
Sean Barrett 2015-11-08 01:22:30 -08:00
parent 16fc63404d
commit 876aea3dbe
2 changed files with 87 additions and 53 deletions
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136
stb_image.h
View File

@ -4598,19 +4598,22 @@ static int stbi__shiftsigned(int v, int shift, int bits)
return result;
}
static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp)
typedef struct
{
stbi_uc *out;
unsigned int mr=0,mg=0,mb=0,ma=0, all_a=255;
stbi_uc pal[256][4];
int psize=0,i,j,compress=0,width;
int bpp, flip_vertically, pad, target, offset, hsz;
int bpp, offset, hsz;
unsigned int mr,mg,mb,ma, all_a;
} stbi__bmp_data;
static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
{
int hsz;
if (stbi__get8(s) != 'B' || stbi__get8(s) != 'M') return stbi__errpuc("not BMP", "Corrupt BMP");
stbi__get32le(s); // discard filesize
stbi__get16le(s); // discard reserved
stbi__get16le(s); // discard reserved
offset = stbi__get32le(s);
hsz = stbi__get32le(s);
info->offset = stbi__get32le(s);
info->hsz = hsz = stbi__get32le(s);
if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108 && hsz != 124) return stbi__errpuc("unknown BMP", "BMP type not supported: unknown");
if (hsz == 12) {
s->img_x = stbi__get16le(s);
@ -4620,15 +4623,10 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
s->img_y = stbi__get32le(s);
}
if (stbi__get16le(s) != 1) return stbi__errpuc("bad BMP", "bad BMP");
bpp = stbi__get16le(s);
if (bpp == 1) return stbi__errpuc("monochrome", "BMP type not supported: 1-bit");
flip_vertically = ((int) s->img_y) > 0;
s->img_y = abs((int) s->img_y);
if (hsz == 12) {
if (bpp < 24)
psize = (offset - 14 - 24) / 3;
} else {
compress = stbi__get32le(s);
info->bpp = stbi__get16le(s);
if (info->bpp == 1) return stbi__errpuc("monochrome", "BMP type not supported: 1-bit");
if (hsz != 12) {
int compress = stbi__get32le(s);
if (compress == 1 || compress == 2) return stbi__errpuc("BMP RLE", "BMP type not supported: RLE");
stbi__get32le(s); // discard sizeof
stbi__get32le(s); // discard hres
@ -4642,26 +4640,26 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
stbi__get32le(s);
stbi__get32le(s);
}
if (bpp == 16 || bpp == 32) {
mr = mg = mb = 0;
if (info->bpp == 16 || info->bpp == 32) {
info->mr = info->mg = info->mb = 0;
if (compress == 0) {
if (bpp == 32) {
mr = 0xffu << 16;
mg = 0xffu << 8;
mb = 0xffu << 0;
ma = 0xffu << 24;
all_a = 0; // if all_a is 0 at end, then we loaded alpha channel but it was all 0
if (info->bpp == 32) {
info->mr = 0xffu << 16;
info->mg = 0xffu << 8;
info->mb = 0xffu << 0;
info->ma = 0xffu << 24;
info->all_a = 0; // if all_a is 0 at end, then we loaded alpha channel but it was all 0
} else {
mr = 31u << 10;
mg = 31u << 5;
mb = 31u << 0;
info->mr = 31u << 10;
info->mg = 31u << 5;
info->mb = 31u << 0;
}
} else if (compress == 3) {
mr = stbi__get32le(s);
mg = stbi__get32le(s);
mb = stbi__get32le(s);
info->mr = stbi__get32le(s);
info->mg = stbi__get32le(s);
info->mb = stbi__get32le(s);
// not documented, but generated by photoshop and handled by mspaint
if (mr == mg && mg == mb) {
if (info->mr == info->mg && info->mg == info->mb) {
// ?!?!?
return stbi__errpuc("bad BMP", "bad BMP");
}
@ -4669,11 +4667,13 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
return stbi__errpuc("bad BMP", "bad BMP");
}
} else {
STBI_ASSERT(hsz == 108 || hsz == 124);
mr = stbi__get32le(s);
mg = stbi__get32le(s);
mb = stbi__get32le(s);
ma = stbi__get32le(s);
int i;
if (hsz != 108 && hsz != 124)
return stbi__errpuc("bad BMP", "bad BMP");
info->mr = stbi__get32le(s);
info->mg = stbi__get32le(s);
info->mb = stbi__get32le(s);
info->ma = stbi__get32le(s);
stbi__get32le(s); // discard color space
for (i=0; i < 12; ++i)
stbi__get32le(s); // discard color space parameters
@ -4684,35 +4684,68 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
stbi__get32le(s); // discard reserved
}
}
if (bpp < 16)
psize = (offset - 14 - hsz) >> 2;
}
return (void *) 1;
}
static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp)
{
stbi_uc *out;
unsigned int mr=0,mg=0,mb=0,ma=0, all_a;
stbi_uc pal[256][4];
int psize=0,i,j,width;
int flip_vertically, pad, target;
stbi__bmp_data info;
info.all_a = 255;
if (stbi__bmp_parse_header(s, &info) == NULL)
return NULL; // error code already set
flip_vertically = ((int) s->img_y) > 0;
s->img_y = abs((int) s->img_y);
mr = info.mr;
mg = info.mg;
mb = info.mb;
ma = info.ma;
all_a = info.all_a;
if (info.hsz == 12) {
if (info.bpp < 24)
psize = (info.offset - 14 - 24) / 3;
} else {
if (info.bpp < 16)
psize = (info.offset - 14 - info.hsz) >> 2;
}
s->img_n = ma ? 4 : 3;
if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
target = req_comp;
else
target = s->img_n; // if they want monochrome, we'll post-convert
out = (stbi_uc *) stbi__malloc(target * s->img_x * s->img_y);
if (!out) return stbi__errpuc("outofmem", "Out of memory");
if (bpp < 16) {
if (info.bpp < 16) {
int z=0;
if (psize == 0 || psize > 256) { STBI_FREE(out); return stbi__errpuc("invalid", "Corrupt BMP"); }
for (i=0; i < psize; ++i) {
pal[i][2] = stbi__get8(s);
pal[i][1] = stbi__get8(s);
pal[i][0] = stbi__get8(s);
if (hsz != 12) stbi__get8(s);
if (info.hsz != 12) stbi__get8(s);
pal[i][3] = 255;
}
stbi__skip(s, offset - 14 - hsz - psize * (hsz == 12 ? 3 : 4));
if (bpp == 4) width = (s->img_x + 1) >> 1;
else if (bpp == 8) width = s->img_x;
stbi__skip(s, info.offset - 14 - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
if (info.bpp == 4) width = (s->img_x + 1) >> 1;
else if (info.bpp == 8) width = s->img_x;
else { STBI_FREE(out); return stbi__errpuc("bad bpp", "Corrupt BMP"); }
pad = (-width)&3;
for (j=0; j < (int) s->img_y; ++j) {
for (i=0; i < (int) s->img_x; i += 2) {
int v=stbi__get8(s),v2=0;
if (bpp == 4) {
if (info.bpp == 4) {
v2 = v & 15;
v >>= 4;
}
@ -4721,7 +4754,7 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
out[z++] = pal[v][2];
if (target == 4) out[z++] = 255;
if (i+1 == (int) s->img_x) break;
v = (bpp == 8) ? stbi__get8(s) : v2;
v = (info.bpp == 8) ? stbi__get8(s) : v2;
out[z++] = pal[v][0];
out[z++] = pal[v][1];
out[z++] = pal[v][2];
@ -4733,14 +4766,14 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
int rshift=0,gshift=0,bshift=0,ashift=0,rcount=0,gcount=0,bcount=0,acount=0;
int z = 0;
int easy=0;
stbi__skip(s, offset - 14 - hsz);
if (bpp == 24) width = 3 * s->img_x;
else if (bpp == 16) width = 2*s->img_x;
stbi__skip(s, info.offset - 14 - info.hsz);
if (info.bpp == 24) width = 3 * s->img_x;
else if (info.bpp == 16) width = 2*s->img_x;
else /* bpp = 32 and pad = 0 */ width=0;
pad = (-width) & 3;
if (bpp == 24) {
if (info.bpp == 24) {
easy = 1;
} else if (bpp == 32) {
} else if (info.bpp == 32) {
if (mb == 0xff && mg == 0xff00 && mr == 0x00ff0000 && ma == 0xff000000)
easy = 2;
}
@ -4765,6 +4798,7 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
if (target == 4) out[z++] = a;
}
} else {
int bpp = info.bpp;
for (i=0; i < (int) s->img_x; ++i) {
stbi__uint32 v = (bpp == 16 ? (stbi__uint32) stbi__get16le(s) : stbi__get32le(s));
int a;

4
tests/image_test.c
View File

@ -7,7 +7,7 @@
#define STB_DEFINE
#include "stb.h"
#define PNGSUITE_PRIMARY
//#define PNGSUITE_PRIMARY
#if 0
void test_ycbcr(void)
@ -65,7 +65,7 @@ int main(int argc, char **argv)
int w,h;
//test_ycbcr();
#if 1
#if 0
// test hdr asserts
for (h=0; h < 100; h += 2)
for (w=0; w < 200; ++w)