mirror of
https://github.com/python-pillow/Pillow.git
synced 2024-11-16 14:46:58 +03:00
368 lines
13 KiB
C
368 lines
13 KiB
C
/*
|
|
* The Python Imaging Library.
|
|
* $Id$
|
|
*
|
|
* coder for ZIP (deflated) image data
|
|
*
|
|
* History:
|
|
* 96-12-29 fl created
|
|
* 96-12-30 fl adaptive filter selection, encoder tuning
|
|
*
|
|
* Copyright (c) Fredrik Lundh 1996.
|
|
* Copyright (c) Secret Labs AB 1997.
|
|
*
|
|
* See the README file for information on usage and redistribution.
|
|
*/
|
|
|
|
#include "Imaging.h"
|
|
|
|
#ifdef HAVE_LIBZ
|
|
|
|
#include "ZipCodecs.h"
|
|
|
|
int
|
|
ImagingZipEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
|
|
ZIPSTATE *context = (ZIPSTATE *)state->context;
|
|
int err;
|
|
int compress_level, compress_type;
|
|
UINT8 *ptr;
|
|
int i, bpp, s, sum;
|
|
ImagingSectionCookie cookie;
|
|
|
|
if (!state->state) {
|
|
/* Initialization */
|
|
|
|
/* Valid modes are ZIP_PNG, ZIP_PNG_PALETTE, and ZIP_TIFF */
|
|
|
|
/* overflow check for malloc */
|
|
if (state->bytes > INT_MAX - 1) {
|
|
state->errcode = IMAGING_CODEC_MEMORY;
|
|
return -1;
|
|
}
|
|
|
|
/* Expand standard buffer to make room for the filter selector,
|
|
and allocate filter buffers */
|
|
free(state->buffer);
|
|
/* malloc check ok, overflow checked above */
|
|
state->buffer = (UINT8 *)malloc(state->bytes + 1);
|
|
context->previous = (UINT8 *)malloc(state->bytes + 1);
|
|
context->prior = (UINT8 *)malloc(state->bytes + 1);
|
|
context->up = (UINT8 *)malloc(state->bytes + 1);
|
|
context->average = (UINT8 *)malloc(state->bytes + 1);
|
|
context->paeth = (UINT8 *)malloc(state->bytes + 1);
|
|
if (!state->buffer || !context->previous || !context->prior || !context->up ||
|
|
!context->average || !context->paeth) {
|
|
free(context->paeth);
|
|
free(context->average);
|
|
free(context->up);
|
|
free(context->prior);
|
|
free(context->previous);
|
|
state->errcode = IMAGING_CODEC_MEMORY;
|
|
return -1;
|
|
}
|
|
|
|
/* Initialise filter buffers */
|
|
state->buffer[0] = 0;
|
|
context->prior[0] = 1;
|
|
context->up[0] = 2;
|
|
context->average[0] = 3;
|
|
context->paeth[0] = 4;
|
|
|
|
/* Initialise previous buffer to black */
|
|
memset(context->previous, 0, state->bytes + 1);
|
|
|
|
/* Setup compression context */
|
|
context->z_stream.zalloc = (alloc_func)0;
|
|
context->z_stream.zfree = (free_func)0;
|
|
context->z_stream.opaque = (voidpf)0;
|
|
context->z_stream.next_in = 0;
|
|
context->z_stream.avail_in = 0;
|
|
|
|
compress_level =
|
|
(context->optimize) ? Z_BEST_COMPRESSION : context->compress_level;
|
|
|
|
if (context->compress_type == -1) {
|
|
compress_type =
|
|
(context->mode == ZIP_PNG) ? Z_FILTERED : Z_DEFAULT_STRATEGY;
|
|
} else {
|
|
compress_type = context->compress_type;
|
|
}
|
|
|
|
err = deflateInit2(
|
|
&context->z_stream,
|
|
/* compression level */
|
|
compress_level,
|
|
/* compression method */
|
|
Z_DEFLATED,
|
|
/* compression memory resources */
|
|
15,
|
|
9,
|
|
/* compression strategy (image data are filtered)*/
|
|
compress_type);
|
|
if (err < 0) {
|
|
state->errcode = IMAGING_CODEC_CONFIG;
|
|
return -1;
|
|
}
|
|
|
|
if (context->dictionary && context->dictionary_size > 0) {
|
|
err = deflateSetDictionary(
|
|
&context->z_stream,
|
|
(unsigned char *)context->dictionary,
|
|
context->dictionary_size);
|
|
if (err < 0) {
|
|
state->errcode = IMAGING_CODEC_CONFIG;
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* Ready to decode */
|
|
state->state = 1;
|
|
}
|
|
|
|
/* Setup the destination buffer */
|
|
context->z_stream.next_out = buf;
|
|
context->z_stream.avail_out = bytes;
|
|
if (context->z_stream.next_in && context->z_stream.avail_in > 0) {
|
|
/* We have some data from previous round, deflate it first */
|
|
err = deflate(&context->z_stream, Z_NO_FLUSH);
|
|
|
|
if (err < 0) {
|
|
/* Something went wrong inside the compression library */
|
|
if (err == Z_DATA_ERROR) {
|
|
state->errcode = IMAGING_CODEC_BROKEN;
|
|
} else if (err == Z_MEM_ERROR) {
|
|
state->errcode = IMAGING_CODEC_MEMORY;
|
|
} else {
|
|
state->errcode = IMAGING_CODEC_CONFIG;
|
|
}
|
|
free(context->paeth);
|
|
free(context->average);
|
|
free(context->up);
|
|
free(context->prior);
|
|
free(context->previous);
|
|
deflateEnd(&context->z_stream);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
ImagingSectionEnter(&cookie);
|
|
for (;;) {
|
|
switch (state->state) {
|
|
case 1:
|
|
|
|
/* Compress image data */
|
|
while (context->z_stream.avail_out > 0) {
|
|
if (state->y >= state->ysize) {
|
|
/* End of image; now flush compressor buffers */
|
|
state->state = 2;
|
|
break;
|
|
}
|
|
|
|
/* Stuff image data into the compressor */
|
|
state->shuffle(
|
|
state->buffer + 1,
|
|
(UINT8 *)im->image[state->y + state->yoff] +
|
|
state->xoff * im->pixelsize,
|
|
state->xsize);
|
|
|
|
state->y++;
|
|
|
|
context->output = state->buffer;
|
|
|
|
if (context->mode == ZIP_PNG) {
|
|
/* Filter the image data. For each line, select
|
|
the filter that gives the least total distance
|
|
from zero for the filtered data (taken from
|
|
LIBPNG) */
|
|
|
|
bpp = (state->bits + 7) / 8;
|
|
|
|
/* 0. No filter */
|
|
for (i = 1, sum = 0; i <= state->bytes; i++) {
|
|
UINT8 v = state->buffer[i];
|
|
sum += (v < 128) ? v : 256 - v;
|
|
}
|
|
|
|
/* 2. Up. We'll test this first to save time when
|
|
an image line is identical to the one above. */
|
|
if (sum > 0) {
|
|
for (i = 1, s = 0; i <= state->bytes; i++) {
|
|
UINT8 v = state->buffer[i] - context->previous[i];
|
|
context->up[i] = v;
|
|
s += (v < 128) ? v : 256 - v;
|
|
}
|
|
if (s < sum) {
|
|
context->output = context->up;
|
|
sum = s; /* 0 if line was duplicated */
|
|
}
|
|
}
|
|
|
|
/* 1. Prior */
|
|
if (sum > 0) {
|
|
for (i = 1, s = 0; i <= bpp; i++) {
|
|
UINT8 v = state->buffer[i];
|
|
context->prior[i] = v;
|
|
s += (v < 128) ? v : 256 - v;
|
|
}
|
|
for (; i <= state->bytes; i++) {
|
|
UINT8 v = state->buffer[i] - state->buffer[i - bpp];
|
|
context->prior[i] = v;
|
|
s += (v < 128) ? v : 256 - v;
|
|
}
|
|
if (s < sum) {
|
|
context->output = context->prior;
|
|
sum = s; /* 0 if line is solid */
|
|
}
|
|
}
|
|
|
|
/* 3. Average (not very common in real-life images,
|
|
so its only used with the optimize option) */
|
|
if (context->optimize && sum > 0) {
|
|
for (i = 1, s = 0; i <= bpp; i++) {
|
|
UINT8 v = state->buffer[i] - context->previous[i] / 2;
|
|
context->average[i] = v;
|
|
s += (v < 128) ? v : 256 - v;
|
|
}
|
|
for (; i <= state->bytes; i++) {
|
|
UINT8 v =
|
|
state->buffer[i] -
|
|
(state->buffer[i - bpp] + context->previous[i]) / 2;
|
|
context->average[i] = v;
|
|
s += (v < 128) ? v : 256 - v;
|
|
}
|
|
if (s < sum) {
|
|
context->output = context->average;
|
|
sum = s;
|
|
}
|
|
}
|
|
|
|
/* 4. Paeth */
|
|
if (sum > 0) {
|
|
for (i = 1, s = 0; i <= bpp; i++) {
|
|
UINT8 v = state->buffer[i] - context->previous[i];
|
|
context->paeth[i] = v;
|
|
s += (v < 128) ? v : 256 - v;
|
|
}
|
|
for (; i <= state->bytes; i++) {
|
|
UINT8 v;
|
|
int a, b, c;
|
|
int pa, pb, pc;
|
|
|
|
/* fetch pixels */
|
|
a = state->buffer[i - bpp];
|
|
b = context->previous[i];
|
|
c = context->previous[i - bpp];
|
|
|
|
/* distances to surrounding pixels */
|
|
pa = abs(b - c);
|
|
pb = abs(a - c);
|
|
pc = abs(a + b - 2 * c);
|
|
|
|
/* pick predictor with the shortest distance */
|
|
v = state->buffer[i] - ((pa <= pb && pa <= pc) ? a
|
|
: (pb <= pc) ? b
|
|
: c);
|
|
context->paeth[i] = v;
|
|
s += (v < 128) ? v : 256 - v;
|
|
}
|
|
if (s < sum) {
|
|
context->output = context->paeth;
|
|
sum = s;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Compress this line */
|
|
context->z_stream.next_in = context->output;
|
|
context->z_stream.avail_in = state->bytes + 1;
|
|
|
|
err = deflate(&context->z_stream, Z_NO_FLUSH);
|
|
|
|
if (err < 0) {
|
|
/* Something went wrong inside the compression library */
|
|
if (err == Z_DATA_ERROR) {
|
|
state->errcode = IMAGING_CODEC_BROKEN;
|
|
} else if (err == Z_MEM_ERROR) {
|
|
state->errcode = IMAGING_CODEC_MEMORY;
|
|
} else {
|
|
state->errcode = IMAGING_CODEC_CONFIG;
|
|
}
|
|
free(context->paeth);
|
|
free(context->average);
|
|
free(context->up);
|
|
free(context->prior);
|
|
free(context->previous);
|
|
deflateEnd(&context->z_stream);
|
|
ImagingSectionLeave(&cookie);
|
|
return -1;
|
|
}
|
|
|
|
/* Swap buffer pointers */
|
|
ptr = state->buffer;
|
|
state->buffer = context->previous;
|
|
context->previous = ptr;
|
|
}
|
|
|
|
if (context->z_stream.avail_out == 0) {
|
|
break; /* Buffer full */
|
|
}
|
|
|
|
case 2:
|
|
|
|
/* End of image data; flush compressor buffers */
|
|
|
|
while (context->z_stream.avail_out > 0) {
|
|
err = deflate(&context->z_stream, Z_FINISH);
|
|
|
|
if (err == Z_STREAM_END) {
|
|
free(context->paeth);
|
|
free(context->average);
|
|
free(context->up);
|
|
free(context->prior);
|
|
free(context->previous);
|
|
|
|
deflateEnd(&context->z_stream);
|
|
|
|
state->errcode = IMAGING_CODEC_END;
|
|
|
|
break;
|
|
}
|
|
|
|
if (context->z_stream.avail_out == 0) {
|
|
break; /* Buffer full */
|
|
}
|
|
}
|
|
}
|
|
ImagingSectionLeave(&cookie);
|
|
return bytes - context->z_stream.avail_out;
|
|
}
|
|
|
|
/* Should never ever arrive here... */
|
|
state->errcode = IMAGING_CODEC_CONFIG;
|
|
ImagingSectionLeave(&cookie);
|
|
return -1;
|
|
}
|
|
|
|
/* -------------------------------------------------------------------- */
|
|
/* Cleanup */
|
|
/* -------------------------------------------------------------------- */
|
|
|
|
int
|
|
ImagingZipEncodeCleanup(ImagingCodecState state) {
|
|
ZIPSTATE *context = (ZIPSTATE *)state->context;
|
|
|
|
if (context->dictionary) {
|
|
free(context->dictionary);
|
|
context->dictionary = NULL;
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
const char *
|
|
ImagingZipVersion(void) {
|
|
return zlibVersion();
|
|
}
|
|
|
|
#endif
|