Initial import of vendor/pnglite
This commit is contained in:
Toomas Soome
commit
a70c2a23d0
25
LICENSE
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25
LICENSE
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@ -0,0 +1,25 @@
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pnglite.h - Interface for pnglite library
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Copyright (c) 2007 Daniel Karling
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source
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distribution.
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Daniel Karling
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daniel.karling@gmail.com
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5
README.md
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5
README.md
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@ -0,0 +1,5 @@
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pnglite
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====
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#### A pretty small png library
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Currently all documentation resides in pnglite.h.
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862
pnglite.c
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862
pnglite.c
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@ -0,0 +1,862 @@
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/* pnglite.c - pnglite library
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For conditions of distribution and use, see copyright notice in pnglite.h
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*/
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#define DO_CRC_CHECKS 1
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#define USE_ZLIB 1
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#if USE_ZLIB
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#include <zlib.h>
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#else
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#include "zlite.h"
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "pnglite.h"
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static png_alloc_t png_alloc;
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static png_free_t png_free;
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static size_t file_read(png_t* png, void* out, size_t size, size_t numel)
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{
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size_t result;
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if(png->read_fun)
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{
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result = png->read_fun(out, size, numel, png->user_pointer);
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}
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else
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{
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if(!out)
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{
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result = fseek(png->user_pointer, (long)(size*numel), SEEK_CUR);
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}
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else
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{
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result = fread(out, size, numel, png->user_pointer);
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}
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}
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return result;
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}
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static size_t file_write(png_t* png, void* p, size_t size, size_t numel)
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{
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size_t result;
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if(png->write_fun)
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{
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result = png->write_fun(p, size, numel, png->user_pointer);
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}
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else
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{
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result = fwrite(p, size, numel, png->user_pointer);
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}
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return result;
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}
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static int file_read_ul(png_t* png, unsigned *out)
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{
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unsigned char buf[4];
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if(file_read(png, buf, 1, 4) != 4)
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return PNG_FILE_ERROR;
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*out = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
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return PNG_NO_ERROR;
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}
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static int file_write_ul(png_t* png, unsigned in)
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{
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unsigned char buf[4];
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buf[0] = (in>>24) & 0xff;
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buf[1] = (in>>16) & 0xff;
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buf[2] = (in>>8) & 0xff;
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buf[3] = (in) & 0xff;
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if(file_write(png, buf, 1, 4) != 4)
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return PNG_FILE_ERROR;
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return PNG_NO_ERROR;
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}
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static unsigned get_ul(unsigned char* buf)
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{
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unsigned result;
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unsigned char foo[4];
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memcpy(foo, buf, 4);
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result = (foo[0]<<24) | (foo[1]<<16) | (foo[2]<<8) | foo[3];
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return result;
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}
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static unsigned set_ul(unsigned char* buf, unsigned in)
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{
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buf[0] = (in>>24) & 0xff;
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buf[1] = (in>>16) & 0xff;
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buf[2] = (in>>8) & 0xff;
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buf[3] = (in) & 0xff;
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return PNG_NO_ERROR;
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}
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int png_init(png_alloc_t pngalloc, png_free_t pngfree)
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{
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if(pngalloc)
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png_alloc = pngalloc;
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else
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png_alloc = &malloc;
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if(pngfree)
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png_free = pngfree;
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else
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png_free = &free;
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return PNG_NO_ERROR;
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}
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static int png_get_bpp(png_t* png)
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{
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int bpp;
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switch(png->color_type)
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{
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case PNG_GREYSCALE:
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bpp = 1; break;
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case PNG_TRUECOLOR:
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bpp = 3; break;
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case PNG_INDEXED:
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bpp = 1; break;
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case PNG_GREYSCALE_ALPHA:
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bpp = 2; break;
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case PNG_TRUECOLOR_ALPHA:
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bpp = 4; break;
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default:
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return PNG_FILE_ERROR;
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}
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bpp *= png->depth/8;
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return bpp;
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}
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static int png_read_ihdr(png_t* png)
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{
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unsigned length;
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#if DO_CRC_CHECKS
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unsigned orig_crc;
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unsigned calc_crc;
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#endif
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unsigned char ihdr[13+4]; /* length should be 13, make room for type (IHDR) */
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file_read_ul(png, &length);
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if(length != 13)
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{
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printf("%d\n", length);
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return PNG_CRC_ERROR;
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}
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if(file_read(png, ihdr, 1, 13+4) != 13+4)
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return PNG_EOF_ERROR;
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#if DO_CRC_CHECKS
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file_read_ul(png, &orig_crc);
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calc_crc = crc32(0L, 0, 0);
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calc_crc = crc32(calc_crc, ihdr, 13+4);
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if(orig_crc != calc_crc)
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return PNG_CRC_ERROR;
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#else
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file_read_ul(png);
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#endif
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png->width = get_ul(ihdr+4);
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png->height = get_ul(ihdr+8);
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png->depth = ihdr[12];
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png->color_type = ihdr[13];
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png->compression_method = ihdr[14];
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png->filter_method = ihdr[15];
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png->interlace_method = ihdr[16];
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if(png->color_type == PNG_INDEXED)
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return PNG_NOT_SUPPORTED;
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if(png->depth != 8 && png->depth != 16)
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return PNG_NOT_SUPPORTED;
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if(png->interlace_method)
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return PNG_NOT_SUPPORTED;
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return PNG_NO_ERROR;
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}
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static int png_write_ihdr(png_t* png)
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{
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unsigned char ihdr[13+4];
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unsigned char *p = ihdr;
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unsigned crc;
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file_write(png, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 1, 8);
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file_write_ul(png, 13);
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*p = 'I'; p++;
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*p = 'H'; p++;
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*p = 'D'; p++;
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*p = 'R'; p++;
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set_ul(p, png->width); p+=4;
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set_ul(p, png->height); p+=4;
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*p = png->depth; p++;
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*p = png->color_type; p++;
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*p = 0; p++;
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*p = 0; p++;
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*p = 0; p++;
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file_write(png, ihdr, 1, 13+4);
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crc = crc32(0L, 0, 0);
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crc = crc32(crc, ihdr, 13+4);
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file_write_ul(png, crc);
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return PNG_NO_ERROR;
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}
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void png_print_info(png_t* png)
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{
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printf("PNG INFO:\n");
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printf("\twidth:\t\t%d\n", png->width);
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printf("\theight:\t\t%d\n", png->height);
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printf("\tdepth:\t\t%d\n", png->depth);
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printf("\tcolor:\t\t");
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switch(png->color_type)
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{
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case PNG_GREYSCALE: printf("greyscale\n"); break;
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case PNG_TRUECOLOR: printf("truecolor\n"); break;
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case PNG_INDEXED: printf("palette\n"); break;
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case PNG_GREYSCALE_ALPHA: printf("greyscale with alpha\n"); break;
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case PNG_TRUECOLOR_ALPHA: printf("truecolor with alpha\n"); break;
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default: printf("unknown, this is not good\n"); break;
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}
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printf("\tcompression:\t%s\n", png->compression_method?"unknown, this is not good":"inflate/deflate");
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printf("\tfilter:\t\t%s\n", png->filter_method?"unknown, this is not good":"adaptive");
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printf("\tinterlace:\t%s\n", png->interlace_method?"interlace":"no interlace");
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}
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int png_open_read(png_t* png, png_read_callback_t read_fun, void* user_pointer)
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{
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char header[8];
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int result;
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png->read_fun = read_fun;
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png->write_fun = 0;
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png->user_pointer = user_pointer;
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if(!read_fun && !user_pointer)
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return PNG_WRONG_ARGUMENTS;
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if(file_read(png, header, 1, 8) != 8)
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return PNG_EOF_ERROR;
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if(memcmp(header, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 8) != 0)
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return PNG_HEADER_ERROR;
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result = png_read_ihdr(png);
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png->bpp = (unsigned char)png_get_bpp(png);
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return result;
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}
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int png_open_write(png_t* png, png_write_callback_t write_fun, void* user_pointer)
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{
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png->write_fun = write_fun;
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png->read_fun = 0;
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png->user_pointer = user_pointer;
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if(!write_fun && !user_pointer)
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return PNG_WRONG_ARGUMENTS;
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return PNG_NO_ERROR;
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}
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int png_open(png_t* png, png_read_callback_t read_fun, void* user_pointer)
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{
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return png_open_read(png, read_fun, user_pointer);
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}
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int png_open_file_read(png_t *png, const char* filename)
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{
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FILE* fp = fopen(filename, "rb");
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if(!fp)
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return PNG_FILE_ERROR;
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return png_open_read(png, 0, fp);
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}
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int png_open_file_write(png_t *png, const char* filename)
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{
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FILE* fp = fopen(filename, "wb");
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if(!fp)
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return PNG_FILE_ERROR;
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return png_open_write(png, 0, fp);
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}
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int png_open_file(png_t *png, const char* filename)
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{
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return png_open_file_read(png, filename);
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}
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int png_close_file(png_t* png)
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{
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fclose(png->user_pointer);
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return PNG_NO_ERROR;
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}
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static int png_init_deflate(png_t* png, unsigned char* data, int datalen)
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{
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z_stream *stream;
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png->zs = png_alloc(sizeof(z_stream));
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stream = png->zs;
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if(!stream)
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return PNG_MEMORY_ERROR;
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memset(stream, 0, sizeof(z_stream));
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if(deflateInit(stream, Z_DEFAULT_COMPRESSION) != Z_OK)
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return PNG_ZLIB_ERROR;
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stream->next_in = data;
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stream->avail_in = datalen;
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return PNG_NO_ERROR;
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}
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static int png_init_inflate(png_t* png)
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{
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#if USE_ZLIB
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z_stream *stream;
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png->zs = png_alloc(sizeof(z_stream));
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#else
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zl_stream *stream;
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png->zs = png_alloc(sizeof(zl_stream));
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#endif
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stream = png->zs;
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if(!stream)
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return PNG_MEMORY_ERROR;
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#if USE_ZLIB
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memset(stream, 0, sizeof(z_stream));
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if(inflateInit(stream) != Z_OK)
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return PNG_ZLIB_ERROR;
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#else
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memset(stream, 0, sizeof(zl_stream));
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if(z_inflateInit(stream) != Z_OK)
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return PNG_ZLIB_ERROR;
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#endif
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|
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stream->next_out = png->png_data;
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stream->avail_out = png->png_datalen;
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return PNG_NO_ERROR;
|
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}
|
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|
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static int png_end_deflate(png_t* png)
|
||||
{
|
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z_stream *stream = png->zs;
|
||||
|
||||
if(!stream)
|
||||
return PNG_MEMORY_ERROR;
|
||||
|
||||
deflateEnd(stream);
|
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|
||||
png_free(png->zs);
|
||||
|
||||
return PNG_NO_ERROR;
|
||||
}
|
||||
|
||||
static int png_end_inflate(png_t* png)
|
||||
{
|
||||
#if USE_ZLIB
|
||||
z_stream *stream = png->zs;
|
||||
#else
|
||||
zl_stream *stream = png->zs;
|
||||
#endif
|
||||
|
||||
if(!stream)
|
||||
return PNG_MEMORY_ERROR;
|
||||
|
||||
#if USE_ZLIB
|
||||
if(inflateEnd(stream) != Z_OK)
|
||||
#else
|
||||
if(z_inflateEnd(stream) != Z_OK)
|
||||
#endif
|
||||
{
|
||||
printf("ZLIB says: %s\n", stream->msg);
|
||||
return PNG_ZLIB_ERROR;
|
||||
}
|
||||
|
||||
png_free(png->zs);
|
||||
|
||||
return PNG_NO_ERROR;
|
||||
}
|
||||
|
||||
static int png_inflate(png_t* png, unsigned char* data, int len)
|
||||
{
|
||||
int result;
|
||||
#if USE_ZLIB
|
||||
z_stream *stream = png->zs;
|
||||
#else
|
||||
zl_stream *stream = png->zs;
|
||||
#endif
|
||||
|
||||
if(!stream)
|
||||
return PNG_MEMORY_ERROR;
|
||||
|
||||
stream->next_in = data;
|
||||
stream->avail_in = len;
|
||||
|
||||
#if USE_ZLIB
|
||||
result = inflate(stream, Z_SYNC_FLUSH);
|
||||
#else
|
||||
result = z_inflate(stream);
|
||||
#endif
|
||||
|
||||
if(result != Z_STREAM_END && result != Z_OK)
|
||||
{
|
||||
printf("%s\n", stream->msg);
|
||||
return PNG_ZLIB_ERROR;
|
||||
}
|
||||
|
||||
if(stream->avail_in != 0)
|
||||
return PNG_ZLIB_ERROR;
|
||||
|
||||
return PNG_NO_ERROR;
|
||||
}
|
||||
|
||||
static int png_deflate(png_t* png, char* outdata, int outlen, int *outwritten)
|
||||
{
|
||||
int result;
|
||||
|
||||
z_stream *stream = png->zs;
|
||||
|
||||
if(!stream)
|
||||
return PNG_MEMORY_ERROR;
|
||||
|
||||
stream->next_out = (unsigned char*)outdata;
|
||||
stream->avail_out = outlen;
|
||||
|
||||
result = deflate(stream, Z_SYNC_FLUSH);
|
||||
|
||||
*outwritten = outlen - stream->avail_out;
|
||||
|
||||
if(result != Z_STREAM_END && result != Z_OK)
|
||||
{
|
||||
printf("%s\n", stream->msg);
|
||||
return PNG_ZLIB_ERROR;
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
static int png_write_idats(png_t* png, unsigned char* data)
|
||||
{
|
||||
unsigned char *chunk;
|
||||
unsigned long written;
|
||||
unsigned long crc;
|
||||
unsigned size = png->width * png->height * png->bpp + png->height;
|
||||
unsigned chunk_size = compressBound(size);
|
||||
|
||||
(void)png_init_deflate;
|
||||
(void)png_end_deflate;
|
||||
(void)png_deflate;
|
||||
|
||||
chunk = png_alloc(chunk_size + 4);
|
||||
memcpy(chunk, "IDAT", 4);
|
||||
|
||||
written = chunk_size;
|
||||
compress(chunk+4, &written, data, size);
|
||||
|
||||
crc = crc32(0L, Z_NULL, 0);
|
||||
crc = crc32(crc, chunk, written+4);
|
||||
set_ul(chunk+written+4, crc);
|
||||
file_write_ul(png, written);
|
||||
file_write(png, chunk, 1, written+8);
|
||||
png_free(chunk);
|
||||
|
||||
file_write_ul(png, 0);
|
||||
file_write(png, "IEND", 1, 4);
|
||||
crc = crc32(0L, (const unsigned char *)"IEND", 4);
|
||||
file_write_ul(png, crc);
|
||||
|
||||
return PNG_NO_ERROR;
|
||||
}
|
||||
|
||||
static int png_read_idat(png_t* png, unsigned length)
|
||||
{
|
||||
#if DO_CRC_CHECKS
|
||||
unsigned orig_crc;
|
||||
unsigned calc_crc;
|
||||
#endif
|
||||
|
||||
if(!png->readbuf || png->readbuflen < length)
|
||||
{
|
||||
if (png->readbuf)
|
||||
{
|
||||
png_free(png->readbuf);
|
||||
}
|
||||
png->readbuf = png_alloc(length);
|
||||
png->readbuflen = length;
|
||||
}
|
||||
|
||||
if(!png->readbuf)
|
||||
{
|
||||
return PNG_MEMORY_ERROR;
|
||||
}
|
||||
|
||||
if(file_read(png, png->readbuf, 1, length) != length)
|
||||
{
|
||||
return PNG_FILE_ERROR;
|
||||
}
|
||||
|
||||
#if DO_CRC_CHECKS
|
||||
calc_crc = crc32(0L, Z_NULL, 0);
|
||||
calc_crc = crc32(calc_crc, (unsigned char*)"IDAT", 4);
|
||||
calc_crc = crc32(calc_crc, (unsigned char*)png->readbuf, length);
|
||||
|
||||
file_read_ul(png, &orig_crc);
|
||||
|
||||
if(orig_crc != calc_crc)
|
||||
{
|
||||
return PNG_CRC_ERROR;
|
||||
}
|
||||
#else
|
||||
file_read_ul(png);
|
||||
#endif
|
||||
|
||||
return png_inflate(png, png->readbuf, length);
|
||||
}
|
||||
|
||||
static int png_process_chunk(png_t* png)
|
||||
{
|
||||
int result = PNG_NO_ERROR;
|
||||
unsigned type;
|
||||
unsigned length;
|
||||
|
||||
file_read_ul(png, &length);
|
||||
|
||||
if(file_read(png, &type, 1, 4) != 4)
|
||||
return PNG_FILE_ERROR;
|
||||
|
||||
if(type == *(unsigned int*)"IDAT") /* if we found an idat, all other idats should be followed with no other chunks in between */
|
||||
{
|
||||
if(!png->png_data) /* first IDAT */
|
||||
{
|
||||
png->png_datalen = png->width * png->height * png->bpp + png->height;
|
||||
png->png_data = png_alloc(png->png_datalen);
|
||||
}
|
||||
|
||||
if(!png->png_data)
|
||||
return PNG_MEMORY_ERROR;
|
||||
|
||||
if(!png->zs)
|
||||
{
|
||||
result = png_init_inflate(png);
|
||||
if(result != PNG_NO_ERROR)
|
||||
return result;
|
||||
}
|
||||
|
||||
return png_read_idat(png, length);
|
||||
}
|
||||
else if(type == *(unsigned int*)"IEND")
|
||||
{
|
||||
return PNG_DONE;
|
||||
}
|
||||
else
|
||||
{
|
||||
file_read(png, 0, 1, length + 4); /* unknown chunk */
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
static void png_filter_sub(int stride, unsigned char* in, unsigned char* out, int len)
|
||||
{
|
||||
int i;
|
||||
unsigned char a = 0;
|
||||
|
||||
for(i = 0; i < len; i++)
|
||||
{
|
||||
if(i >= stride)
|
||||
a = out[i - stride];
|
||||
|
||||
out[i] = in[i] + a;
|
||||
}
|
||||
}
|
||||
|
||||
static void png_filter_up(int stride, unsigned char* in, unsigned char* out, unsigned char* prev_line, int len)
|
||||
{
|
||||
int i;
|
||||
|
||||
if(prev_line)
|
||||
{
|
||||
for(i = 0; i < len; i++)
|
||||
out[i] = in[i] + prev_line[i];
|
||||
}
|
||||
else
|
||||
memcpy(out, in, len);
|
||||
}
|
||||
|
||||
static void png_filter_average(int stride, unsigned char* in, unsigned char* out, unsigned char* prev_line, int len)
|
||||
{
|
||||
int i;
|
||||
unsigned char a = 0;
|
||||
unsigned char b = 0;
|
||||
unsigned int sum = 0;
|
||||
|
||||
for(i = 0; i < len; i++)
|
||||
{
|
||||
if(prev_line)
|
||||
b = prev_line[i];
|
||||
|
||||
if(i >= stride)
|
||||
a = out[i - stride];
|
||||
|
||||
sum = a;
|
||||
sum += b;
|
||||
|
||||
out[i] = (char)(in[i] + sum/2);
|
||||
}
|
||||
}
|
||||
|
||||
static unsigned char png_paeth(unsigned char a, unsigned char b, unsigned char c)
|
||||
{
|
||||
int p = (int)a + b - c;
|
||||
int pa = abs(p - a);
|
||||
int pb = abs(p - b);
|
||||
int pc = abs(p - c);
|
||||
|
||||
int pr;
|
||||
|
||||
if(pa <= pb && pa <= pc)
|
||||
pr = a;
|
||||
else if(pb <= pc)
|
||||
pr = b;
|
||||
else
|
||||
pr = c;
|
||||
|
||||
return (char)pr;
|
||||
}
|
||||
|
||||
static void png_filter_paeth(int stride, unsigned char* in, unsigned char* out, unsigned char* prev_line, int len)
|
||||
{
|
||||
int i;
|
||||
unsigned char a;
|
||||
unsigned char b;
|
||||
unsigned char c;
|
||||
|
||||
for(i = 0; i < len; i++)
|
||||
{
|
||||
if(prev_line && i >= stride)
|
||||
{
|
||||
a = out[i - stride];
|
||||
b = prev_line[i];
|
||||
c = prev_line[i - stride];
|
||||
}
|
||||
else
|
||||
{
|
||||
if(prev_line)
|
||||
b = prev_line[i];
|
||||
else
|
||||
b = 0;
|
||||
|
||||
if(i >= stride)
|
||||
a = out[i - stride];
|
||||
else
|
||||
a = 0;
|
||||
|
||||
c = 0;
|
||||
}
|
||||
|
||||
out[i] = in[i] + png_paeth(a, b, c);
|
||||
}
|
||||
}
|
||||
|
||||
static int png_filter(png_t* png, unsigned char* data)
|
||||
{
|
||||
return PNG_NO_ERROR;
|
||||
}
|
||||
|
||||
static int png_unfilter(png_t* png, unsigned char* data)
|
||||
{
|
||||
unsigned i;
|
||||
unsigned pos = 0;
|
||||
unsigned outpos = 0;
|
||||
unsigned char *filtered = png->png_data;
|
||||
|
||||
int stride = png->bpp;
|
||||
|
||||
while(pos < png->png_datalen)
|
||||
{
|
||||
unsigned char filter = filtered[pos];
|
||||
|
||||
pos++;
|
||||
|
||||
if(png->depth == 16)
|
||||
{
|
||||
for(i = 0; i < png->width * stride; i+=2)
|
||||
{
|
||||
*(short*)(filtered+pos+i) = (filtered[pos+i] << 8) | filtered[pos+i+1];
|
||||
}
|
||||
}
|
||||
|
||||
switch(filter)
|
||||
{
|
||||
case 0: /* none */
|
||||
memcpy(data+outpos, filtered+pos, png->width * stride);
|
||||
break;
|
||||
case 1: /* sub */
|
||||
png_filter_sub(stride, filtered+pos, data+outpos, png->width * stride);
|
||||
break;
|
||||
case 2: /* up */
|
||||
if(outpos)
|
||||
png_filter_up(stride, filtered+pos, data+outpos, data + outpos - (png->width*stride), png->width*stride);
|
||||
else
|
||||
png_filter_up(stride, filtered+pos, data+outpos, 0, png->width*stride);
|
||||
break;
|
||||
case 3: /* average */
|
||||
if(outpos)
|
||||
png_filter_average(stride, filtered+pos, data+outpos, data + outpos - (png->width*stride), png->width*stride);
|
||||
else
|
||||
png_filter_average(stride, filtered+pos, data+outpos, 0, png->width*stride);
|
||||
break;
|
||||
case 4: /* paeth */
|
||||
if(outpos)
|
||||
png_filter_paeth(stride, filtered+pos, data+outpos, data + outpos - (png->width*stride), png->width*stride);
|
||||
else
|
||||
png_filter_paeth(stride, filtered+pos, data+outpos, 0, png->width*stride);
|
||||
break;
|
||||
default:
|
||||
return PNG_UNKNOWN_FILTER;
|
||||
}
|
||||
|
||||
outpos += png->width * stride;
|
||||
pos += png->width * stride;
|
||||
}
|
||||
|
||||
return PNG_NO_ERROR;
|
||||
}
|
||||
|
||||
int png_get_data(png_t* png, unsigned char* data)
|
||||
{
|
||||
int result = PNG_NO_ERROR;
|
||||
|
||||
png->zs = NULL;
|
||||
png->png_datalen = 0;
|
||||
png->png_data = NULL;
|
||||
png->readbuf = NULL;
|
||||
png->readbuflen = 0;
|
||||
|
||||
while(result == PNG_NO_ERROR)
|
||||
{
|
||||
result = png_process_chunk(png);
|
||||
}
|
||||
|
||||
if (png->readbuf)
|
||||
{
|
||||
png_free(png->readbuf);
|
||||
png->readbuflen = 0;
|
||||
}
|
||||
if (png->zs)
|
||||
{
|
||||
png_end_inflate(png);
|
||||
}
|
||||
|
||||
if(result != PNG_DONE)
|
||||
{
|
||||
png_free(png->png_data);
|
||||
return result;
|
||||
}
|
||||
|
||||
result = png_unfilter(png, data);
|
||||
|
||||
png_free(png->png_data);
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
int png_set_data(png_t* png, unsigned width, unsigned height, char depth, int color, unsigned char* data)
|
||||
{
|
||||
int i;
|
||||
unsigned char *filtered;
|
||||
png->width = width;
|
||||
png->height = height;
|
||||
png->depth = depth;
|
||||
png->color_type = color;
|
||||
png->bpp = png_get_bpp(png);
|
||||
|
||||
filtered = png_alloc(width * height * png->bpp + height);
|
||||
|
||||
for(i = 0; i < png->height; i++)
|
||||
{
|
||||
filtered[i*png->width*png->bpp+i] = 0;
|
||||
memcpy(&filtered[i*png->width*png->bpp+i+1], data + i * png->width*png->bpp, png->width*png->bpp);
|
||||
}
|
||||
|
||||
png_filter(png, filtered);
|
||||
png_write_ihdr(png);
|
||||
png_write_idats(png, filtered);
|
||||
|
||||
png_free(filtered);
|
||||
|
||||
return PNG_NO_ERROR;
|
||||
}
|
||||
|
||||
char* png_error_string(int error)
|
||||
{
|
||||
switch(error)
|
||||
{
|
||||
case PNG_NO_ERROR:
|
||||
return "No error";
|
||||
case PNG_FILE_ERROR:
|
||||
return "Unknown file error.";
|
||||
case PNG_HEADER_ERROR:
|
||||
return "No PNG header found. Are you sure this is a PNG?";
|
||||
case PNG_IO_ERROR:
|
||||
return "Failure while reading file.";
|
||||
case PNG_EOF_ERROR:
|
||||
return "Reached end of file.";
|
||||
case PNG_CRC_ERROR:
|
||||
return "CRC or chunk length error.";
|
||||
case PNG_MEMORY_ERROR:
|
||||
return "Could not allocate memory.";
|
||||
case PNG_ZLIB_ERROR:
|
||||
return "zlib reported an error.";
|
||||
case PNG_UNKNOWN_FILTER:
|
||||
return "Unknown filter method used in scanline.";
|
||||
case PNG_DONE:
|
||||
return "PNG done";
|
||||
case PNG_NOT_SUPPORTED:
|
||||
return "The PNG is unsupported by pnglite, too bad for you!";
|
||||
case PNG_WRONG_ARGUMENTS:
|
||||
return "Wrong combination of arguments passed to png_open. You must use either a read_function or supply a file pointer to use.";
|
||||
default:
|
||||
return "Unknown error.";
|
||||
};
|
||||
}
|
||||
232
pnglite.h
Normal file
232
pnglite.h
Normal file
|
|
@ -0,0 +1,232 @@
|
|||
/* pnglite.h - Interface for pnglite library
|
||||
Copyright (c) 2007 Daniel Karling
|
||||
|
||||
This software is provided 'as-is', without any express or implied
|
||||
warranty. In no event will the authors be held liable for any damages
|
||||
arising from the use of this software.
|
||||
|
||||
Permission is granted to anyone to use this software for any purpose,
|
||||
including commercial applications, and to alter it and redistribute it
|
||||
freely, subject to the following restrictions:
|
||||
|
||||
1. The origin of this software must not be misrepresented; you must not
|
||||
claim that you wrote the original software. If you use this software
|
||||
in a product, an acknowledgment in the product documentation would be
|
||||
appreciated but is not required.
|
||||
|
||||
2. Altered source versions must be plainly marked as such, and must not be
|
||||
misrepresented as being the original software.
|
||||
|
||||
3. This notice may not be removed or altered from any source
|
||||
distribution.
|
||||
|
||||
Daniel Karling
|
||||
daniel.karling@gmail.com
|
||||
*/
|
||||
|
||||
|
||||
#ifndef _PNGLITE_H_
|
||||
#define _PNGLITE_H_
|
||||
|
||||
#include <string.h>
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C"{
|
||||
#endif
|
||||
|
||||
/*
|
||||
Enumerations for pnglite.
|
||||
Negative numbers are error codes and 0 and up are okay responses.
|
||||
*/
|
||||
|
||||
enum
|
||||
{
|
||||
PNG_DONE = 1,
|
||||
PNG_NO_ERROR = 0,
|
||||
PNG_FILE_ERROR = -1,
|
||||
PNG_HEADER_ERROR = -2,
|
||||
PNG_IO_ERROR = -3,
|
||||
PNG_EOF_ERROR = -4,
|
||||
PNG_CRC_ERROR = -5,
|
||||
PNG_MEMORY_ERROR = -6,
|
||||
PNG_ZLIB_ERROR = -7,
|
||||
PNG_UNKNOWN_FILTER = -8,
|
||||
PNG_NOT_SUPPORTED = -9,
|
||||
PNG_WRONG_ARGUMENTS = -10
|
||||
};
|
||||
|
||||
/*
|
||||
The five different kinds of color storage in PNG files.
|
||||
*/
|
||||
|
||||
enum
|
||||
{
|
||||
PNG_GREYSCALE = 0,
|
||||
PNG_TRUECOLOR = 2,
|
||||
PNG_INDEXED = 3,
|
||||
PNG_GREYSCALE_ALPHA = 4,
|
||||
PNG_TRUECOLOR_ALPHA = 6
|
||||
};
|
||||
|
||||
/*
|
||||
Typedefs for callbacks.
|
||||
*/
|
||||
|
||||
typedef unsigned (*png_write_callback_t)(void* input, size_t size, size_t numel, void* user_pointer);
|
||||
typedef unsigned (*png_read_callback_t)(void* output, size_t size, size_t numel, void* user_pointer);
|
||||
typedef void (*png_free_t)(void* p);
|
||||
typedef void * (*png_alloc_t)(size_t s);
|
||||
|
||||
typedef struct
|
||||
{
|
||||
void* zs; /* pointer to z_stream */
|
||||
png_read_callback_t read_fun;
|
||||
png_write_callback_t write_fun;
|
||||
void* user_pointer;
|
||||
|
||||
unsigned char* png_data;
|
||||
unsigned png_datalen;
|
||||
|
||||
unsigned width;
|
||||
unsigned height;
|
||||
unsigned char depth;
|
||||
unsigned char color_type;
|
||||
unsigned char compression_method;
|
||||
unsigned char filter_method;
|
||||
unsigned char interlace_method;
|
||||
unsigned char bpp;
|
||||
|
||||
unsigned char* readbuf;
|
||||
unsigned readbuflen;
|
||||
} png_t;
|
||||
|
||||
/*
|
||||
Function: png_init
|
||||
|
||||
This function initializes pnglite. The parameters can be used to set your own memory allocation routines following these formats:
|
||||
|
||||
> void* (*custom_alloc)(size_t s)
|
||||
> void (*custom_free)(void* p)
|
||||
Parameters:
|
||||
pngalloc - Pointer to custom allocation routine. If 0 is passed, malloc from libc will be used.
|
||||
pngfree - Pointer to custom free routine. If 0 is passed, free from libc will be used.
|
||||
|
||||
Returns:
|
||||
Always returns PNG_NO_ERROR.
|
||||
*/
|
||||
|
||||
int png_init(png_alloc_t pngalloc, png_free_t pngfree);
|
||||
|
||||
/*
|
||||
Function: png_open_file
|
||||
|
||||
This function is used to open a png file with the internal file IO system. This function should be used instead of
|
||||
png_open if no custom read function is used.
|
||||
|
||||
Parameters:
|
||||
png - Empty png_t struct.
|
||||
filename - Filename of the file to be opened.
|
||||
|
||||
Returns:
|
||||
PNG_NO_ERROR on success, otherwise an error code.
|
||||
*/
|
||||
|
||||
int png_open_file(png_t *png, const char* filename);
|
||||
|
||||
int png_open_file_read(png_t *png, const char* filename);
|
||||
int png_open_file_write(png_t *png, const char* filename);
|
||||
|
||||
/*
|
||||
Function: png_open
|
||||
|
||||
This function reads or writes a png from/to the specified callback. The callbacks should be of the format:
|
||||
|
||||
> size_t (*png_write_callback_t)(void* input, size_t size, size_t numel, void* user_pointer);
|
||||
> size_t (*png_read_callback_t)(void* output, size_t size, size_t numel, void* user_pointer).
|
||||
|
||||
Only one callback has to be specified. The read callback in case of PNG reading, otherwise the write callback.
|
||||
|
||||
Writing:
|
||||
The callback will be called like fwrite.
|
||||
|
||||
Reading:
|
||||
The callback will be called each time pnglite needs more data. The callback should read as much data as requested,
|
||||
or return 0. This should always be possible if the PNG is sane. If the output-buffer is a null-pointer the callback
|
||||
should only skip ahead the specified number of elements. If the callback is a null-pointer the user_pointer will be
|
||||
treated as a file pointer (use png_open_file instead).
|
||||
|
||||
Parameters:
|
||||
png - png_t struct
|
||||
read_fun - Callback function for reading.
|
||||
user_pointer - User pointer to be passed to read_fun.
|
||||
|
||||
Returns:
|
||||
PNG_NO_ERROR on success, otherwise an error code.
|
||||
*/
|
||||
|
||||
int png_open(png_t* png, png_read_callback_t read_fun, void* user_pointer);
|
||||
|
||||
int png_open_read(png_t* png, png_read_callback_t read_fun, void* user_pointer);
|
||||
int png_open_write(png_t* png, png_write_callback_t write_fun, void* user_pointer);
|
||||
|
||||
/*
|
||||
Function: png_print_info
|
||||
|
||||
This function prints some info about the opened png file to stdout.
|
||||
|
||||
Parameters:
|
||||
png - png struct to get info from.
|
||||
*/
|
||||
|
||||
void png_print_info(png_t* png);
|
||||
|
||||
/*
|
||||
Function: png_error_string
|
||||
|
||||
This function translates an error code to a human readable string.
|
||||
|
||||
Parameters:
|
||||
error - Error code.
|
||||
|
||||
Returns:
|
||||
Pointer to string.
|
||||
*/
|
||||
|
||||
char* png_error_string(int error);
|
||||
|
||||
/*
|
||||
Function: png_get_data
|
||||
|
||||
This function decodes the opened png file and stores the result in data. data should be big enough to hold the decoded png. Required size will be:
|
||||
|
||||
> width*height*(bytes per pixel)
|
||||
|
||||
Parameters:
|
||||
data - Where to store result.
|
||||
|
||||
Returns:
|
||||
PNG_NO_ERROR on success, otherwise an error code.
|
||||
*/
|
||||
|
||||
int png_get_data(png_t* png, unsigned char* data);
|
||||
|
||||
int png_set_data(png_t* png, unsigned width, unsigned height, char depth, int color, unsigned char* data);
|
||||
|
||||
/*
|
||||
Function: png_close_file
|
||||
|
||||
Closes an open png file pointer. Should only be used when the png has been opened with png_open_file.
|
||||
|
||||
Parameters:
|
||||
png - png to close.
|
||||
|
||||
Returns:
|
||||
PNG_NO_ERROR
|
||||
*/
|
||||
|
||||
int png_close_file(png_t* png);
|
||||
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
#endif
|
||||
Loading…
Reference in New Issue
Block a user