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cosmopolitan/third_party/stb/stb_image_write.c
mataha 1bc48bc8e4
Update stb (#885) 
This commit and, by extension, PR attempts to update `stb` in the most
straightforward way possible as well as include fixes from main repo's
unmerged PRs for cases rearing their ugly heads during everyday usage:

 - stb#1299: stb_rect_pack: Make rect_height_compare a stable sort
 - stb#1402: stb_image: Fix "unused invalid_chunk" with STBI_FAILURE_USERMSG
 - stb#1404: stb_image: Fix gif two_back memory address
 - stb#1420: stb_image: Improve error reporting if file operations fail
   within *_from_file functions
 - stb#1445: stb_vorbis: Few static analyzers fixes
 - stb#1487: stb_vorbis: Fix residue classdata bounding for
   f->temp_memory_required
 - stb#1490: stb_vorbis: Fix broken clamp in codebook_decode_deinterleave_repeat
 - stb#1496: stb_image: Fix pnm only build
 - stb#1497: stb_image: Fix memory leaks if stbi__convert failed
 - stb#1498: stb_vorbis: Fix memory leaks in stb_vorbis
 - stb#1499: stb_vorbis: Minor change to prevent the undefined behavior -
   left shift of a negative value
 - stb#1500: stb_vorbis: Fix signed integer overflow

Includes additional small fixes that I felt didn't warrant a separate PR.
2023-12-22 21:39:27 -08:00

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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "third_party/stb/stb_image_write.h"
#include "dsp/core/core.h"
#include "libc/assert.h"
#include "libc/fmt/conv.h"
#include "libc/limits.h"
#include "libc/macros.internal.h"
#include "libc/math.h"
#include "libc/mem/mem.h"
#include "libc/nexgen32e/nexgen32e.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "third_party/zlib/zlib.h"
asm(".ident\t\"\\n\\n\
stb_image_write (Public Domain)\\n\
Credit: Sean Barrett, et al.\\n\
http://nothings.org/stb\"");
#define STBIW_UCHAR(x) (unsigned char)((x)&0xff)
#define stbiw__wpng4(o, a, b, c, d) \
((o)[0] = STBIW_UCHAR(a), (o)[1] = STBIW_UCHAR(b), (o)[2] = STBIW_UCHAR(c), \
(o)[3] = STBIW_UCHAR(d), (o) += 4)
#define stbiw__wp32(data, v) \
stbiw__wpng4(data, (v) >> 24, (v) >> 16, (v) >> 8, (v));
#define stbiw__wptag(data, s) stbiw__wpng4(data, s[0], s[1], s[2], s[3])
typedef struct {
stbi_write_func *func;
void *context;
unsigned char buffer[64];
int buf_used;
} stbi__write_context;
int stbi_write_png_compression_level = 4;
int stbi_write_tga_with_rle = 1;
int stbi_write_force_png_filter = -1;
static int stbi__flip_vertically_on_write = 0;
void stbi_flip_vertically_on_write(int flag) {
stbi__flip_vertically_on_write = flag;
}
// initialize a callback-based context
static void stbi__start_write_callbacks(stbi__write_context *s,
stbi_write_func *c, void *context) {
s->func = c;
s->context = context;
}
static void stbi__stdio_write(void *context, void *data, int size) {
fwrite(data, 1, size, (FILE *)context);
}
static int stbi__start_write_file(stbi__write_context *s,
const char *filename) {
FILE *f = fopen(filename, "wb");
stbi__start_write_callbacks(s, stbi__stdio_write, (void *)f);
return f != NULL;
}
static void stbi__end_write_file(stbi__write_context *s) {
fclose((FILE *)s->context);
}
static void stbiw__writefv(stbi__write_context *s, const char *fmt, va_list v) {
while (*fmt) {
switch (*fmt++) {
case ' ':
break;
case '1': {
unsigned char x = STBIW_UCHAR(va_arg(v, int));
s->func(s->context, &x, 1);
break;
}
case '2': {
int x = va_arg(v, int);
unsigned char b[2];
b[0] = STBIW_UCHAR(x);
b[1] = STBIW_UCHAR(x >> 8);
s->func(s->context, b, 2);
break;
}
case '4': {
unsigned int x = va_arg(v, int);
unsigned char b[4];
b[0] = STBIW_UCHAR(x);
b[1] = STBIW_UCHAR(x >> 8);
b[2] = STBIW_UCHAR(x >> 16);
b[3] = STBIW_UCHAR(x >> 24);
s->func(s->context, b, 4);
break;
}
default:
__builtin_unreachable();
}
}
}
static void stbiw__writef(stbi__write_context *s, const char *fmt, ...) {
va_list v;
va_start(v, fmt);
stbiw__writefv(s, fmt, v);
va_end(v);
}
static void stbiw__write_flush(stbi__write_context *s) {
if (s->buf_used) {
s->func(s->context, &s->buffer, s->buf_used);
s->buf_used = 0;
}
}
static void stbiw__putc(stbi__write_context *s, unsigned char c) {
s->func(s->context, &c, 1);
}
static void stbiw__write1(stbi__write_context *s, unsigned char a) {
if ((size_t)s->buf_used + 1 > sizeof(s->buffer)) stbiw__write_flush(s);
s->buffer[s->buf_used++] = a;
}
static void stbiw__write3(stbi__write_context *s, unsigned char a,
unsigned char b, unsigned char c) {
int n;
if ((size_t)s->buf_used + 3 > sizeof(s->buffer)) stbiw__write_flush(s);
n = s->buf_used;
s->buf_used = n + 3;
s->buffer[n + 0] = a;
s->buffer[n + 1] = b;
s->buffer[n + 2] = c;
}
static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp,
int write_alpha, int expand_mono,
unsigned char *d) {
unsigned char bg[3] = {255, 0, 255}, px[3];
int k;
if (write_alpha < 0) stbiw__write1(s, d[comp - 1]);
switch (comp) {
case 2: // 2 pixels = mono + alpha, alpha is written separately, so same as
// 1-channel case
case 1:
if (expand_mono)
stbiw__write3(s, d[0], d[0], d[0]); // monochrome bmp
else
stbiw__write1(s, d[0]); // monochrome TGA
break;
case 4:
if (!write_alpha) {
// composite against pink background
for (k = 0; k < 3; ++k) px[k] = bg[k] + ((d[k] - bg[k]) * d[3]) / 255;
stbiw__write3(s, px[1 - rgb_dir], px[1], px[1 + rgb_dir]);
break;
}
/* FALLTHROUGH */
case 3:
stbiw__write3(s, d[1 - rgb_dir], d[1], d[1 + rgb_dir]);
break;
}
if (write_alpha > 0) stbiw__write1(s, d[comp - 1]);
}
static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir,
int x, int y, int comp, void *data,
int write_alpha, int scanline_pad,
int expand_mono) {
unsigned int zero = 0;
int i, j, j_end;
if (y <= 0) return;
if (stbi__flip_vertically_on_write) vdir *= -1;
if (vdir < 0) {
j_end = -1;
j = y - 1;
} else {
j_end = y;
j = 0;
}
for (; j != j_end; j += vdir) {
for (i = 0; i < x; ++i) {
unsigned char *d = (unsigned char *)data + (j * x + i) * comp;
stbiw__write_pixel(s, rgb_dir, comp, write_alpha, expand_mono, d);
}
stbiw__write_flush(s);
s->func(s->context, &zero, scanline_pad);
}
}
static int stbiw__outfile(stbi__write_context *s, int rgb_dir, int vdir, int x,
int y, int comp, int expand_mono, void *data,
int alpha, int pad, const char *fmt, ...) {
if (y < 0 || x < 0) {
return 0;
} else {
va_list v;
va_start(v, fmt);
stbiw__writefv(s, fmt, v);
va_end(v);
stbiw__write_pixels(s, rgb_dir, vdir, x, y, comp, data, alpha, pad,
expand_mono);
return 1;
}
}
static int stbi_write_bmp_core(stbi__write_context *s, int x, int y, int comp,
const void *data) {
if (comp != 4) {
// write RGB bitmap
int pad;
pad = (-x * 3) & 3;
return stbiw__outfile(s, -1, -1, x, y, comp, 1, (void *)data, 0, pad,
"11 4 22 4"
"4 44 22 444444",
'B', 'M', 14 + 40 + (x * 3 + pad) * y, 0, 0,
14 + 40, // file header
40, x, y, 1, 24, 0, 0, 0, 0, 0, 0); // bitmap header
} else {
// RGBA bitmaps need a v4 header
// use BI_BITFIELDS mode with 32bpp and alpha mask
// (straight BI_RGB with alpha mask doesn't work in most readers)
return stbiw__outfile(s, -1, -1, x, y, comp, 1, (void *)data, 1, 0,
"11 4 22 4"
"4 44 22 444444 4444 4 444 444 444 444",
'B', 'M', 14 + 108 + x * y * 4, 0, 0,
14 + 108, // file header
108, x, y, 1, 32, 3, 0, 0, 0, 0, 0, 0xff0000, 0xff00,
0xff, 0xff000000u, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0); // bitmap V4 header
}
}
int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x, int y,
int comp, const void *data) {
stbi__write_context s = {0};
stbi__start_write_callbacks(&s, func, context);
return stbi_write_bmp_core(&s, x, y, comp, data);
}
int stbi_write_bmp(char const *filename, int x, int y, int comp,
const void *data) {
stbi__write_context s = {0};
if (stbi__start_write_file(&s, filename)) {
int r = stbi_write_bmp_core(&s, x, y, comp, data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
static int stbi_write_tga_core(stbi__write_context *s, int x, int y, int comp,
void *data) {
int has_alpha = (comp == 2 || comp == 4);
int colorbytes = has_alpha ? comp - 1 : comp;
int format =
colorbytes < 2
? 3
: 2; // 3 color channels (RGB/RGBA) = 2, 1 color channel (Y/YA) = 3
if (y < 0 || x < 0) return 0;
if (!stbi_write_tga_with_rle) {
return stbiw__outfile(s, -1, -1, x, y, comp, 0, (void *)data, has_alpha, 0,
"111 221 2222 11", 0, 0, format, 0, 0, 0, 0, 0, x, y,
(colorbytes + has_alpha) * 8, has_alpha * 8);
} else {
int i, j, k;
int jend, jdir;
stbiw__writef(s, "111 221 2222 11", 0, 0, format + 8, 0, 0, 0, 0, 0, x, y,
(colorbytes + has_alpha) * 8, has_alpha * 8);
if (stbi__flip_vertically_on_write) {
j = 0;
jend = y;
jdir = 1;
} else {
j = y - 1;
jend = -1;
jdir = -1;
}
for (; j != jend; j += jdir) {
unsigned char *row = (unsigned char *)data + j * x * comp;
int len;
for (i = 0; i < x; i += len) {
unsigned char *begin = row + i * comp;
int diff = 1;
len = 1;
if (i < x - 1) {
++len;
diff = memcmp(begin, row + (i + 1) * comp, comp);
if (diff) {
const unsigned char *prev = begin;
for (k = i + 2; k < x && len < 128; ++k) {
if (memcmp(prev, row + k * comp, comp)) {
prev += comp;
++len;
} else {
--len;
break;
}
}
} else {
for (k = i + 2; k < x && len < 128; ++k) {
if (!memcmp(begin, row + k * comp, comp)) {
++len;
} else {
break;
}
}
}
}
if (diff) {
unsigned char header = STBIW_UCHAR(len - 1);
stbiw__write1(s, header);
for (k = 0; k < len; ++k) {
stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin + k * comp);
}
} else {
unsigned char header = STBIW_UCHAR(len - 129);
stbiw__write1(s, header);
stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin);
}
}
}
stbiw__write_flush(s);
}
return 1;
}
int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x, int y,
int comp, const void *data) {
stbi__write_context s = {0};
stbi__start_write_callbacks(&s, func, context);
return stbi_write_tga_core(&s, x, y, comp, (void *)data);
}
int stbi_write_tga(char const *filename, int x, int y, int comp,
const void *data) {
stbi__write_context s = {0};
if (stbi__start_write_file(&s, filename)) {
int r = stbi_write_tga_core(&s, x, y, comp, (void *)data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
/*
* PNG writer
*/
static unsigned char *stbi_zlib_compress(unsigned char *data, int size,
int *out_len, int quality) {
unsigned long newsize;
unsigned char *newdata, *trimdata;
assert(0 <= size && size <= INT_MAX);
if ((newdata = malloc((newsize = compressBound(size)))) &&
compress2(newdata, &newsize, data, size,
stbi_write_png_compression_level) == Z_OK) {
*out_len = newsize;
if ((trimdata = realloc(newdata, newsize))) {
return trimdata;
} else {
return newdata;
}
}
free(newdata);
return NULL;
}
static void stbiw__wpcrc(unsigned char **data, int len) {
unsigned int crc = crc32(0, *data - len - 4, len + 4);
stbiw__wp32(*data, crc);
}
forceinline unsigned char stbiw__paeth(int a, int b, int c) {
int p = a + b - c, pa = abs(p - a), pb = abs(p - b), pc = abs(p - c);
if (pa <= pb && pa <= pc) return STBIW_UCHAR(a);
if (pb <= pc) return STBIW_UCHAR(b);
return STBIW_UCHAR(c);
}
// @OPTIMIZE: provide an option that always forces left-predict or paeth predict
static void stbiw__encode_png_line(const unsigned char *pixels,
int stride_bytes, int width, int height,
int y, int n, int filter_type,
signed char *line_buffer) {
int mapping[] = {0, 1, 2, 3, 4};
int firstmap[] = {0, 1, 0, 5, 6};
const unsigned char *z;
int *mymap, i, type, signed_stride;
mymap = (y != 0) ? mapping : firstmap;
type = mymap[filter_type];
z = pixels +
stride_bytes * (stbi__flip_vertically_on_write ? height - 1 - y : y);
signed_stride = stbi__flip_vertically_on_write ? -stride_bytes : stride_bytes;
if (type == 0) {
memcpy(line_buffer, z, width * n);
return;
}
for (i = 0; i < n; ++i) {
switch (type) {
case 1:
line_buffer[i] = z[i];
break;
case 2:
line_buffer[i] = z[i] - z[i - signed_stride];
break;
case 3:
line_buffer[i] = z[i] - (z[i - signed_stride] >> 1);
break;
case 4:
line_buffer[i] =
(signed char)(z[i] - stbiw__paeth(0, z[i - signed_stride], 0));
break;
case 5:
line_buffer[i] = z[i];
break;
case 6:
line_buffer[i] = z[i];
break;
}
}
switch (type) {
case 1:
for (i = n; i < width * n; ++i) {
line_buffer[i] = z[i] - z[i - n];
}
break;
case 2:
for (i = n; i < width * n; ++i) {
line_buffer[i] = z[i] - z[i - signed_stride];
}
break;
case 3:
for (i = n; i < width * n; ++i) {
line_buffer[i] = z[i] - ((z[i - n] + z[i - signed_stride]) >> 1);
}
break;
case 4:
for (i = n; i < width * n; ++i) {
line_buffer[i] = z[i] - stbiw__paeth(z[i - n], z[i - signed_stride],
z[i - signed_stride - n]);
}
break;
case 5:
for (i = n; i < width * n; ++i) {
line_buffer[i] = z[i] - (z[i - n] >> 1);
}
break;
case 6:
for (i = n; i < width * n; ++i) {
line_buffer[i] = z[i] - stbiw__paeth(z[i - n], 0, 0);
}
break;
}
}
unsigned char *stbi_write_png_to_mem(const unsigned char *pixels,
int stride_bytes, int x, int y, int n,
int *out_len) {
int force_filter = stbi_write_force_png_filter;
int ctype[5] = {-1, 0, 4, 2, 6};
unsigned char sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
unsigned char *out, *o, *filt, *zlib;
signed char *line_buffer;
int j, zlen;
if (stride_bytes == 0) stride_bytes = x * n;
if (force_filter >= 5) {
force_filter = -1;
}
filt = malloc((x * n + 1) * y);
if (!filt) return 0;
line_buffer = malloc(x * n);
if (!line_buffer) {
free(filt);
return 0;
}
for (j = 0; j < y; ++j) {
int filter_type;
if (force_filter > -1) {
filter_type = force_filter;
stbiw__encode_png_line(pixels, stride_bytes, x, y, j, n, force_filter,
line_buffer);
} else { // Estimate the best filter by running through all of them:
int best_filter = 0, best_filter_val = 0x7fffffff, est, i;
for (filter_type = 0; filter_type < 5; filter_type++) {
stbiw__encode_png_line(pixels, stride_bytes, x, y, j, n, filter_type,
line_buffer);
// Estimate the entropy of the line using this filter; the less, the
// better.
est = 0;
for (i = 0; i < x * n; ++i) {
est += abs((signed char)line_buffer[i]);
}
if (est < best_filter_val) {
best_filter_val = est;
best_filter = filter_type;
}
}
if (filter_type != best_filter) { // If the last iteration already got us
// the best filter, don't redo it
stbiw__encode_png_line(pixels, stride_bytes, x, y, j, n, best_filter,
line_buffer);
filter_type = best_filter;
}
}
// when we get here, filter_type contains the filter type, and line_buffer
// contains the data
filt[j * (x * n + 1)] = (unsigned char)filter_type;
memmove(filt + j * (x * n + 1) + 1, line_buffer, x * n);
}
free(line_buffer);
zlib = stbi_zlib_compress(filt, y * (x * n + 1), &zlen,
stbi_write_png_compression_level);
free(filt);
if (!zlib) return 0;
// each tag requires 12 bytes of overhead
out = malloc(8 + 12 + 13 + 12 + zlen + 12);
if (!out) return 0;
*out_len = 8 + 12 + 13 + 12 + zlen + 12;
o = out;
memmove(o, sig, 8);
o += 8;
stbiw__wp32(o, 13); // header length
stbiw__wptag(o, "IHDR");
stbiw__wp32(o, x);
stbiw__wp32(o, y);
*o++ = 8;
*o++ = STBIW_UCHAR(ctype[n]);
*o++ = 0;
*o++ = 0;
*o++ = 0;
stbiw__wpcrc(&o, 13);
stbiw__wp32(o, zlen);
stbiw__wptag(o, "IDAT");
memmove(o, zlib, zlen);
o += zlen;
free(zlib);
stbiw__wpcrc(&o, zlen);
stbiw__wp32(o, 0);
stbiw__wptag(o, "IEND");
stbiw__wpcrc(&o, 0);
assert(o == out + *out_len);
return out;
}
int stbi_write_png(const char *filename, int x, int y, int comp,
const void *data, int stride_bytes) {
int len;
FILE *f;
unsigned char *png;
png = stbi_write_png_to_mem(data, stride_bytes, x, y, comp, &len);
if (png == NULL) return 0;
f = fopen(filename, "wb");
if (!f) {
free(png);
return 0;
}
fwrite(png, 1, len, f);
fclose(f);
free(png);
return 1;
}
int stbi_write_png_to_func(stbi_write_func *func, void *context, int x, int y,
int comp, const void *data, int stride_bytes) {
int len;
unsigned char *png;
png = stbi_write_png_to_mem((const unsigned char *)data, stride_bytes, x, y,
comp, &len);
if (png == NULL) return 0;
func(context, png, len);
free(png);
return 1;
}
/* JPEG writer
*
* This is based on Jon Olick's jo_jpeg.cpp:
* public domain Simple, Minimalistic JPEG writer -
* http://www.jonolick.com/code.html
*/
static const unsigned char stbiw__jpg_ZigZag[] = {
0, 1, 5, 6, 14, 15, 27, 28, 2, 4, 7, 13, 16, 26, 29, 42,
3, 8, 12, 17, 25, 30, 41, 43, 9, 11, 18, 24, 31, 40, 44, 53,
10, 19, 23, 32, 39, 45, 52, 54, 20, 22, 33, 38, 46, 51, 55, 60,
21, 34, 37, 47, 50, 56, 59, 61, 35, 36, 48, 49, 57, 58, 62, 63,
};
static void stbiw__jpg_writeBits(stbi__write_context *s, int *bitBufP,
int *bitCntP, const unsigned short *bs) {
unsigned char c;
unsigned bitBuf, bitCnt;
bitBuf = *bitBufP;
bitCnt = *bitCntP;
bitCnt += bs[1];
bitBuf |= bs[0] << (24 - bitCnt);
while (bitCnt >= 8) {
c = (bitBuf >> 16) & 255;
stbiw__putc(s, c);
if (c == 255) {
stbiw__putc(s, 0);
}
bitBuf <<= 8;
bitCnt -= 8;
}
*bitBufP = bitBuf;
*bitCntP = bitCnt;
}
static void stbiw__jpg_calcBits(int val, unsigned short bits[2]) {
int tmp1 = val < 0 ? -val : val;
val = val < 0 ? val - 1 : val;
bits[1] = 1;
while (tmp1 >>= 1) {
++bits[1];
}
bits[0] = val & ((1u << bits[1]) - 1);
}
static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf,
int *bitCnt, float *CDU, unsigned du_stride,
float *fdtbl, int DC,
const unsigned short HTDC[256][2],
const unsigned short HTAC[256][2]) {
const unsigned short EOB[2] = {HTAC[0x00][0], HTAC[0x00][1]};
const unsigned short M16zeroes[2] = {HTAC[0xF0][0], HTAC[0xF0][1]};
unsigned i, j, diff, end0pos, x, y;
int DU[64];
dctjpeg((void *)CDU, du_stride / 8);
// Quantize/descale/zigzag the coefficients
for (j = 0, y = 0; y < 8; ++y) {
for (x = 0; x < 8; ++x, ++j) {
float v;
i = y * du_stride + x;
v = CDU[i] * fdtbl[j];
DU[stbiw__jpg_ZigZag[j]] = v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f);
}
}
// Encode DC
diff = DU[0] - DC;
if (diff == 0) {
stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTDC[0]);
} else {
unsigned short bits[2];
stbiw__jpg_calcBits(diff, bits);
stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTDC[bits[1]]);
stbiw__jpg_writeBits(s, bitBuf, bitCnt, bits);
}
// Encode ACs
end0pos = 63;
for (; (end0pos > 0) && (DU[end0pos] == 0); --end0pos) {
}
// end0pos = first element in reverse order !=0
if (end0pos == 0) {
stbiw__jpg_writeBits(s, bitBuf, bitCnt, EOB);
return DU[0];
}
for (i = 1; i <= end0pos; ++i) {
unsigned startpos = i;
unsigned nrzeroes;
unsigned short bits[2];
for (; DU[i] == 0 && i <= end0pos; ++i) {
}
nrzeroes = i - startpos;
if (nrzeroes >= 16) {
unsigned lng = nrzeroes >> 4;
unsigned nrmarker;
for (nrmarker = 1; nrmarker <= lng; ++nrmarker) {
stbiw__jpg_writeBits(s, bitBuf, bitCnt, M16zeroes);
}
nrzeroes &= 15;
}
stbiw__jpg_calcBits(DU[i], bits);
stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTAC[(nrzeroes << 4) + bits[1]]);
stbiw__jpg_writeBits(s, bitBuf, bitCnt, bits);
}
if (end0pos != 63) {
stbiw__jpg_writeBits(s, bitBuf, bitCnt, EOB);
}
return DU[0];
}
static int stbi_write_jpg_core(stbi__write_context *s, int width, int height,
int comp, const void *data, int quality) {
static const unsigned char std_dc_luminance_nrcodes[] = {
0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0};
static const unsigned char std_dc_luminance_values[] = {0, 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11};
static const unsigned char std_ac_luminance_nrcodes[] = {
0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d};
static const unsigned char std_ac_luminance_values[] = {
0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06,
0x13, 0x51, 0x61, 0x07, 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72,
0x82, 0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45,
0x46, 0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75,
0x76, 0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3,
0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9,
0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4,
0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa};
static const unsigned char std_dc_chrominance_nrcodes[] = {
0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0};
static const unsigned char std_dc_chrominance_values[] = {0, 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11};
static const unsigned char std_ac_chrominance_nrcodes[] = {
0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77};
static const unsigned char std_ac_chrominance_values[] = {
0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41,
0x51, 0x07, 0x61, 0x71, 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1,
0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44,
0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74,
0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a,
0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf2, 0xf3, 0xf4,
0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa};
// Huffman tables
static const unsigned short YDC_HT[256][2] = {
{0, 2}, {2, 3}, {3, 3}, {4, 3}, {5, 3}, {6, 3},
{14, 4}, {30, 5}, {62, 6}, {126, 7}, {254, 8}, {510, 9}};
static const unsigned short UVDC_HT[256][2] = {
{0, 2}, {1, 2}, {2, 2}, {6, 3}, {14, 4}, {30, 5},
{62, 6}, {126, 7}, {254, 8}, {510, 9}, {1022, 10}, {2046, 11}};
static const unsigned short YAC_HT[256][2] = {
{10, 4}, {0, 2}, {1, 2}, {4, 3}, {11, 4},
{26, 5}, {120, 7}, {248, 8}, {1014, 10}, {65410, 16},
{65411, 16}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {12, 4}, {27, 5}, {121, 7},
{502, 9}, {2038, 11}, {65412, 16}, {65413, 16}, {65414, 16},
{65415, 16}, {65416, 16}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {28, 5}, {249, 8},
{1015, 10}, {4084, 12}, {65417, 16}, {65418, 16}, {65419, 16},
{65420, 16}, {65421, 16}, {65422, 16}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {58, 6},
{503, 9}, {4085, 12}, {65423, 16}, {65424, 16}, {65425, 16},
{65426, 16}, {65427, 16}, {65428, 16}, {65429, 16}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{59, 6}, {1016, 10}, {65430, 16}, {65431, 16}, {65432, 16},
{65433, 16}, {65434, 16}, {65435, 16}, {65436, 16}, {65437, 16},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {122, 7}, {2039, 11}, {65438, 16}, {65439, 16},
{65440, 16}, {65441, 16}, {65442, 16}, {65443, 16}, {65444, 16},
{65445, 16}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {123, 7}, {4086, 12}, {65446, 16},
{65447, 16}, {65448, 16}, {65449, 16}, {65450, 16}, {65451, 16},
{65452, 16}, {65453, 16}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {250, 8}, {4087, 12},
{65454, 16}, {65455, 16}, {65456, 16}, {65457, 16}, {65458, 16},
{65459, 16}, {65460, 16}, {65461, 16}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {504, 9},
{32704, 15}, {65462, 16}, {65463, 16}, {65464, 16}, {65465, 16},
{65466, 16}, {65467, 16}, {65468, 16}, {65469, 16}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{505, 9}, {65470, 16}, {65471, 16}, {65472, 16}, {65473, 16},
{65474, 16}, {65475, 16}, {65476, 16}, {65477, 16}, {65478, 16},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {506, 9}, {65479, 16}, {65480, 16}, {65481, 16},
{65482, 16}, {65483, 16}, {65484, 16}, {65485, 16}, {65486, 16},
{65487, 16}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {1017, 10}, {65488, 16}, {65489, 16},
{65490, 16}, {65491, 16}, {65492, 16}, {65493, 16}, {65494, 16},
{65495, 16}, {65496, 16}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {1018, 10}, {65497, 16},
{65498, 16}, {65499, 16}, {65500, 16}, {65501, 16}, {65502, 16},
{65503, 16}, {65504, 16}, {65505, 16}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {2040, 11},
{65506, 16}, {65507, 16}, {65508, 16}, {65509, 16}, {65510, 16},
{65511, 16}, {65512, 16}, {65513, 16}, {65514, 16}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{65515, 16}, {65516, 16}, {65517, 16}, {65518, 16}, {65519, 16},
{65520, 16}, {65521, 16}, {65522, 16}, {65523, 16}, {65524, 16},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{2041, 11}, {65525, 16}, {65526, 16}, {65527, 16}, {65528, 16},
{65529, 16}, {65530, 16}, {65531, 16}, {65532, 16}, {65533, 16},
{65534, 16}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}};
static const unsigned short UVAC_HT[256][2] = {
{0, 2}, {1, 2}, {4, 3}, {10, 4}, {24, 5},
{25, 5}, {56, 6}, {120, 7}, {500, 9}, {1014, 10},
{4084, 12}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {11, 4}, {57, 6}, {246, 8},
{501, 9}, {2038, 11}, {4085, 12}, {65416, 16}, {65417, 16},
{65418, 16}, {65419, 16}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {26, 5}, {247, 8},
{1015, 10}, {4086, 12}, {32706, 15}, {65420, 16}, {65421, 16},
{65422, 16}, {65423, 16}, {65424, 16}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {27, 5},
{248, 8}, {1016, 10}, {4087, 12}, {65425, 16}, {65426, 16},
{65427, 16}, {65428, 16}, {65429, 16}, {65430, 16}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{58, 6}, {502, 9}, {65431, 16}, {65432, 16}, {65433, 16},
{65434, 16}, {65435, 16}, {65436, 16}, {65437, 16}, {65438, 16},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {59, 6}, {1017, 10}, {65439, 16}, {65440, 16},
{65441, 16}, {65442, 16}, {65443, 16}, {65444, 16}, {65445, 16},
{65446, 16}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {121, 7}, {2039, 11}, {65447, 16},
{65448, 16}, {65449, 16}, {65450, 16}, {65451, 16}, {65452, 16},
{65453, 16}, {65454, 16}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {122, 7}, {2040, 11},
{65455, 16}, {65456, 16}, {65457, 16}, {65458, 16}, {65459, 16},
{65460, 16}, {65461, 16}, {65462, 16}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {249, 8},
{65463, 16}, {65464, 16}, {65465, 16}, {65466, 16}, {65467, 16},
{65468, 16}, {65469, 16}, {65470, 16}, {65471, 16}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{503, 9}, {65472, 16}, {65473, 16}, {65474, 16}, {65475, 16},
{65476, 16}, {65477, 16}, {65478, 16}, {65479, 16}, {65480, 16},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {504, 9}, {65481, 16}, {65482, 16}, {65483, 16},
{65484, 16}, {65485, 16}, {65486, 16}, {65487, 16}, {65488, 16},
{65489, 16}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {505, 9}, {65490, 16}, {65491, 16},
{65492, 16}, {65493, 16}, {65494, 16}, {65495, 16}, {65496, 16},
{65497, 16}, {65498, 16}, {0, 0}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {506, 9}, {65499, 16},
{65500, 16}, {65501, 16}, {65502, 16}, {65503, 16}, {65504, 16},
{65505, 16}, {65506, 16}, {65507, 16}, {0, 0}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {2041, 11},
{65508, 16}, {65509, 16}, {65510, 16}, {65511, 16}, {65512, 16},
{65513, 16}, {65514, 16}, {65515, 16}, {65516, 16}, {0, 0},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{16352, 14}, {65517, 16}, {65518, 16}, {65519, 16}, {65520, 16},
{65521, 16}, {65522, 16}, {65523, 16}, {65524, 16}, {65525, 16},
{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{1018, 10}, {32707, 15}, {65526, 16}, {65527, 16}, {65528, 16},
{65529, 16}, {65530, 16}, {65531, 16}, {65532, 16}, {65533, 16},
{65534, 16}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
{0, 0}};
static const int YQT[] = {
16, 11, 10, 16, 24, 40, 51, 61, 12, 12, 14, 19, 26, 58, 60, 55,
14, 13, 16, 24, 40, 57, 69, 56, 14, 17, 22, 29, 51, 87, 80, 62,
18, 22, 37, 56, 68, 109, 103, 77, 24, 35, 55, 64, 81, 104, 113, 92,
49, 64, 78, 87, 103, 121, 120, 101, 72, 92, 95, 98, 112, 100, 103, 99};
static const int UVQT[] = {17, 18, 24, 47, 99, 99, 99, 99, 18, 21, 26, 66, 99,
99, 99, 99, 24, 26, 56, 99, 99, 99, 99, 99, 47, 66,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99};
static const float aasf[] = {
1.0f * 2.828427125f, 1.387039845f * 2.828427125f,
1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f,
1.0f * 2.828427125f, 0.785694958f * 2.828427125f,
0.541196100f * 2.828427125f, 0.275899379f * 2.828427125f};
int row, col, i, k, subsample;
float fdtbl_Y[64], fdtbl_UV[64];
unsigned char YTable[64], UVTable[64];
if (!data || !width || !height || comp > 4 || comp < 1) {
return 0;
}
quality = quality ? quality : 97;
subsample = quality <= 97 ? 1 : 0;
quality = quality < 1 ? 1 : quality > 100 ? 100 : quality;
quality = quality < 50 ? 5000 / quality : 200 - quality * 2;
for (i = 0; i < 64; ++i) {
int uvti, yti = (YQT[i] * quality + 50) / 100;
YTable[stbiw__jpg_ZigZag[i]] = (unsigned char)(yti < 1 ? 1
: yti > 255 ? 255
: yti);
uvti = (UVQT[i] * quality + 50) / 100;
UVTable[stbiw__jpg_ZigZag[i]] = (unsigned char)(uvti < 1 ? 1
: uvti > 255 ? 255
: uvti);
}
for (row = 0, k = 0; row < 8; ++row) {
for (col = 0; col < 8; ++col, ++k) {
fdtbl_Y[k] = 1 / (YTable[stbiw__jpg_ZigZag[k]] * aasf[row] * aasf[col]);
fdtbl_UV[k] = 1 / (UVTable[stbiw__jpg_ZigZag[k]] * aasf[row] * aasf[col]);
}
}
// Write Headers
{
static const unsigned char head0[] = {
0xFF, 0xD8, 0xFF, 0xE0, 0, 0x10, 'J', 'F', 'I', 'F', 0, 1, 1,
0, 0, 1, 0, 1, 0, 0, 0xFF, 0xDB, 0, 0x84, 0};
static const unsigned char head2[] = {0xFF, 0xDA, 0, 0xC, 3, 1, 0,
2, 0x11, 3, 0x11, 0, 0x3F, 0};
const unsigned char head1[] = {
0xFF,
0xC0,
0,
0x11,
8,
(unsigned char)(height >> 8),
STBIW_UCHAR(height),
(unsigned char)(width >> 8),
STBIW_UCHAR(width),
3,
1,
(unsigned char)(subsample ? 0x22 : 0x11),
0,
2,
0x11,
1,
3,
0x11,
1,
0xFF,
0xC4,
0x01,
0xA2,
0,
};
s->func(s->context, (void *)head0, sizeof(head0));
s->func(s->context, (void *)YTable, sizeof(YTable));
stbiw__putc(s, 1);
s->func(s->context, UVTable, sizeof(UVTable));
s->func(s->context, (void *)head1, sizeof(head1));
s->func(s->context, (void *)(std_dc_luminance_nrcodes + 1),
sizeof(std_dc_luminance_nrcodes) - 1);
s->func(s->context, (void *)std_dc_luminance_values,
sizeof(std_dc_luminance_values));
stbiw__putc(s, 0x10); // HTYACinfo
s->func(s->context, (void *)(std_ac_luminance_nrcodes + 1),
sizeof(std_ac_luminance_nrcodes) - 1);
s->func(s->context, (void *)std_ac_luminance_values,
sizeof(std_ac_luminance_values));
stbiw__putc(s, 1); // HTUDCinfo
s->func(s->context, (void *)(std_dc_chrominance_nrcodes + 1),
sizeof(std_dc_chrominance_nrcodes) - 1);
s->func(s->context, (void *)std_dc_chrominance_values,
sizeof(std_dc_chrominance_values));
stbiw__putc(s, 0x11); // HTUACinfo
s->func(s->context, (void *)(std_ac_chrominance_nrcodes + 1),
sizeof(std_ac_chrominance_nrcodes) - 1);
s->func(s->context, (void *)std_ac_chrominance_values,
sizeof(std_ac_chrominance_values));
s->func(s->context, (void *)head2, sizeof(head2));
}
// Encode 8x8 macroblocks
{
static const unsigned short fillBits[] = {0x7F, 7};
int DCY = 0, DCU = 0, DCV = 0;
int bitBuf = 0, bitCnt = 0;
// comp == 2 is grey+alpha (alpha is ignored)
int ofsG = comp > 2 ? 1 : 0, ofsB = comp > 2 ? 2 : 0;
const unsigned char *dataR = (const unsigned char *)data;
const unsigned char *dataG = dataR + ofsG;
const unsigned char *dataB = dataR + ofsB;
int x, y, pos;
if (subsample) {
for (y = 0; y < height; y += 16) {
for (x = 0; x < width; x += 16) {
float Y[256], U[256], V[256];
for (row = y, pos = 0; row < y + 16; ++row) {
// row >= height => use last input row
int clamped_row = (row < height) ? row : height - 1;
int base_p =
(stbi__flip_vertically_on_write ? (height - 1 - clamped_row)
: clamped_row) *
width * comp;
for (col = x; col < x + 16; ++col, ++pos) {
// if col >= width => use pixel from last input column
int p = base_p + ((col < width) ? col : (width - 1)) * comp;
float r = dataR[p], g = dataG[p], b = dataB[p];
Y[pos] = +0.29900f * r + 0.58700f * g + 0.11400f * b - 128;
U[pos] = -0.16874f * r - 0.33126f * g + 0.50000f * b;
V[pos] = +0.50000f * r - 0.41869f * g - 0.08131f * b;
}
}
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y + 0, 16, fdtbl_Y,
DCY, YDC_HT, YAC_HT);
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y + 8, 16, fdtbl_Y,
DCY, YDC_HT, YAC_HT);
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y + 128, 16, fdtbl_Y,
DCY, YDC_HT, YAC_HT);
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y + 136, 16, fdtbl_Y,
DCY, YDC_HT, YAC_HT);
// subsample U,V
{
float subU[64], subV[64];
int yy, xx;
for (yy = 0, pos = 0; yy < 8; ++yy) {
for (xx = 0; xx < 8; ++xx, ++pos) {
int j = yy * 32 + xx * 2;
subU[pos] =
(U[j + 0] + U[j + 1] + U[j + 16] + U[j + 17]) * 0.25f;
subV[pos] =
(V[j + 0] + V[j + 1] + V[j + 16] + V[j + 17]) * 0.25f;
}
}
DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subU, 8, fdtbl_UV,
DCU, UVDC_HT, UVAC_HT);
DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subV, 8, fdtbl_UV,
DCV, UVDC_HT, UVAC_HT);
}
}
}
} else {
for (y = 0; y < height; y += 8) {
for (x = 0; x < width; x += 8) {
float Y[64], U[64], V[64];
for (row = y, pos = 0; row < y + 8; ++row) {
// row >= height => use last input row
int clamped_row = (row < height) ? row : height - 1;
int base_p =
(stbi__flip_vertically_on_write ? (height - 1 - clamped_row)
: clamped_row) *
width * comp;
for (col = x; col < x + 8; ++col, ++pos) {
// if col >= width => use pixel from last input column
int p = base_p + ((col < width) ? col : (width - 1)) * comp;
float r = dataR[p], g = dataG[p], b = dataB[p];
Y[pos] = +0.29900f * r + 0.58700f * g + 0.11400f * b - 128;
U[pos] = -0.16874f * r - 0.33126f * g + 0.50000f * b;
V[pos] = +0.50000f * r - 0.41869f * g - 0.08131f * b;
}
}
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y, 8, fdtbl_Y, DCY,
YDC_HT, YAC_HT);
DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, U, 8, fdtbl_UV, DCU,
UVDC_HT, UVAC_HT);
DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, V, 8, fdtbl_UV, DCV,
UVDC_HT, UVAC_HT);
}
}
}
// Do the bit alignment of the EOI marker
stbiw__jpg_writeBits(s, &bitBuf, &bitCnt, fillBits);
}
// EOI
stbiw__putc(s, 0xFF);
stbiw__putc(s, 0xD9);
return 1;
}
int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y,
int comp, const void *data, int quality) {
stbi__write_context s = {0};
stbi__start_write_callbacks(&s, func, context);
return stbi_write_jpg_core(&s, x, y, comp, (void *)data, quality);
}
int stbi_write_jpg(char const *filename, int x, int y, int comp,
const void *data, int quality) {
stbi__write_context s = {0};
if (stbi__start_write_file(&s, filename)) {
int r = stbi_write_jpg_core(&s, x, y, comp, data, quality);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
/*
********************************************************************************
Radiance RGBE HDR writer
by Baldur Karlsson */
static void stbiw__linear_to_rgbe(unsigned char *rgbe, float *linear) {
int exponent;
float normalize, maxcomp;
maxcomp = MAX(linear[0], MAX(linear[1], linear[2]));
if (maxcomp < 1e-32f) {
rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
} else {
/* no idea what HDR is but this could probably use clamping */
normalize = (float)frexp(maxcomp, &exponent) * 256.0f / maxcomp;
rgbe[0] = (unsigned char)(linear[0] * normalize);
rgbe[1] = (unsigned char)(linear[1] * normalize);
rgbe[2] = (unsigned char)(linear[2] * normalize);
rgbe[3] = (unsigned char)(exponent + 128);
}
}
static void stbiw__write_run_data(stbi__write_context *s, int length,
unsigned char databyte) {
unsigned char lengthbyte = STBIW_UCHAR(length + 128);
assert(length + 128 <= 255);
s->func(s->context, &lengthbyte, 1);
s->func(s->context, &databyte, 1);
}
static void stbiw__write_dump_data(stbi__write_context *s, int length,
unsigned char *data) {
unsigned char lengthbyte = STBIW_UCHAR(length);
assert(length <=
128); // inconsistent with spec but consistent with official code
s->func(s->context, &lengthbyte, 1);
s->func(s->context, data, length);
}
static void stbiw__write_hdr_scanline(stbi__write_context *s, int width,
int ncomp, unsigned char *scratch,
float *scanline) {
unsigned char scanlineheader[4] = {2, 2, 0, 0};
unsigned char rgbe[4];
float linear[3];
int x;
scanlineheader[2] = (width & 0xff00) >> 8;
scanlineheader[3] = (width & 0x00ff);
/* skip RLE for images too small or large */
if (width < 8 || width >= 32768) {
for (x = 0; x < width; x++) {
switch (ncomp) {
case 4: /* fallthrough */
case 3:
linear[2] = scanline[x * ncomp + 2];
linear[1] = scanline[x * ncomp + 1];
linear[0] = scanline[x * ncomp + 0];
break;
default:
linear[0] = linear[1] = linear[2] = scanline[x * ncomp + 0];
break;
}
stbiw__linear_to_rgbe(rgbe, linear);
s->func(s->context, rgbe, 4);
}
} else {
int c, r;
/* encode into scratch buffer */
for (x = 0; x < width; x++) {
switch (ncomp) {
case 4: /* fallthrough */
case 3:
linear[2] = scanline[x * ncomp + 2];
linear[1] = scanline[x * ncomp + 1];
linear[0] = scanline[x * ncomp + 0];
break;
default:
linear[0] = linear[1] = linear[2] = scanline[x * ncomp + 0];
break;
}
stbiw__linear_to_rgbe(rgbe, linear);
scratch[x + width * 0] = rgbe[0];
scratch[x + width * 1] = rgbe[1];
scratch[x + width * 2] = rgbe[2];
scratch[x + width * 3] = rgbe[3];
}
s->func(s->context, scanlineheader, 4);
/* RLE each component separately */
for (c = 0; c < 4; c++) {
unsigned char *comp = &scratch[width * c];
x = 0;
while (x < width) {
// find first run
r = x;
while (r + 2 < width) {
if (comp[r] == comp[r + 1] && comp[r] == comp[r + 2]) break;
++r;
}
if (r + 2 >= width) r = width;
// dump up to first run
while (x < r) {
int len = r - x;
if (len > 128) len = 128;
stbiw__write_dump_data(s, len, &comp[x]);
x += len;
}
// if there's a run, output it
if (r + 2 < width) { // same test as what we break out of in search
// loop, so only true if we break'd
// find next byte after run
while (r < width && comp[r] == comp[x]) ++r;
// output run up to r
while (x < r) {
int len = r - x;
if (len > 127) len = 127;
stbiw__write_run_data(s, len, comp[x]);
x += len;
}
}
}
}
}
}
static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp,
float *data) {
if (y <= 0 || x <= 0 || data == NULL)
return 0;
else {
// Each component is stored separately. Allocate scratch space for full
// output scanline.
unsigned char *scratch = malloc(x * 4);
int i, len;
char buffer[128];
char header[] =
"#?RADIANCE\n# Written by stb_image_write.h\nFORMAT=32-bit_rle_rgbe\n";
s->func(s->context, header, sizeof(header) - 1);
len = (snprintf)(buffer, sizeof(buffer), "%s\n\n%s%d%s%d\n",
"EXPOSURE= 1.0000000000000", "-Y ", y, " +X ", x);
s->func(s->context, buffer, len);
for (i = 0; i < y; i++) {
stbiw__write_hdr_scanline(
s, x, comp, scratch,
data + comp * x * (stbi__flip_vertically_on_write ? y - 1 - i : i));
}
free(scratch);
return 1;
}
}
int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int x, int y,
int comp, const float *data) {
stbi__write_context s = {0};
stbi__start_write_callbacks(&s, func, context);
return stbi_write_hdr_core(&s, x, y, comp, (float *)data);
}
int stbi_write_hdr(char const *filename, int x, int y, int comp,
const float *data) {
stbi__write_context s = {0};
if (stbi__start_write_file(&s, filename)) {
int r = stbi_write_hdr_core(&s, x, y, comp, (float *)data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
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