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FFmpeg/libavformat/libpng/png.c
Fabrice Bellard 43a7635d09 added stripped down libpng 
Originally committed as revision 1527 to svn://svn.ffmpeg.org/ffmpeg/trunk
2003-02-01 20:51:52 +00:00

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C
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/* png.c - location for general purpose libpng functions
*
* libpng version 1.0.15 - October 3, 2002
* Copyright (c) 1998-2002 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
*/
#define PNG_INTERNAL
#define PNG_NO_EXTERN
#include "png.h"
/* Generate a compiler error if there is an old png.h in the search path. */
typedef version_1_0_15 Your_png_h_is_not_version_1_0_15;
/* Version information for C files. This had better match the version
* string defined in png.h. */
#ifdef PNG_USE_GLOBAL_ARRAYS
/* png_libpng_ver was changed to a function in version 1.0.5c */
const char png_libpng_ver[18] = "1.0.15";
/* png_sig was changed to a function in version 1.0.5c */
/* Place to hold the signature string for a PNG file. */
const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
/* Invoke global declarations for constant strings for known chunk types */
PNG_IHDR;
PNG_IDAT;
PNG_IEND;
PNG_PLTE;
PNG_bKGD;
PNG_cHRM;
PNG_gAMA;
PNG_hIST;
PNG_iCCP;
PNG_iTXt;
PNG_oFFs;
PNG_pCAL;
PNG_sCAL;
PNG_pHYs;
PNG_sBIT;
PNG_sPLT;
PNG_sRGB;
PNG_tEXt;
PNG_tIME;
PNG_tRNS;
PNG_zTXt;
/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* start of interlace block */
const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
/* offset to next interlace block */
const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
/* start of interlace block in the y direction */
const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
/* offset to next interlace block in the y direction */
const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
/* width of interlace block (used in assembler routines only) */
#ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
#endif
/* Height of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
*/
/* Mask to determine which pixels are valid in a pass */
const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
/* Mask to determine which pixels to overwrite while displaying */
const int FARDATA png_pass_dsp_mask[]
= {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
#endif
/* Checks whether the supplied bytes match the PNG signature. We allow
* checking less than the full 8-byte signature so that those apps that
* already read the first few bytes of a file to determine the file type
* can simply check the remaining bytes for extra assurance. Returns
* an integer less than, equal to, or greater than zero if sig is found,
* respectively, to be less than, to match, or be greater than the correct
* PNG signature (this is the same behaviour as strcmp, memcmp, etc).
*/
int PNGAPI
png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
{
png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
if (num_to_check > 8)
num_to_check = 8;
else if (num_to_check < 1)
return (0);
if (start > 7)
return (0);
if (start + num_to_check > 8)
num_to_check = 8 - start;
return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
}
/* Function to allocate memory for zlib and clear it to 0. */
#ifdef PNG_1_0_X
voidpf PNGAPI
#else
voidpf /* private */
#endif
png_zalloc(voidpf png_ptr, uInt items, uInt size)
{
png_uint_32 num_bytes = (png_uint_32)items * size;
png_voidp ptr;
png_structp p=png_ptr;
png_uint_32 save_flags=p->flags;
p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
p->flags=save_flags;
#ifndef PNG_NO_ZALLOC_ZERO
if (ptr == NULL)
return ((voidpf)ptr);
if (num_bytes > (png_uint_32)0x8000L)
{
png_memset(ptr, 0, (png_size_t)0x8000L);
png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
(png_size_t)(num_bytes - (png_uint_32)0x8000L));
}
else
{
png_memset(ptr, 0, (png_size_t)num_bytes);
}
#endif
return ((voidpf)ptr);
}
/* function to free memory for zlib */
#ifdef PNG_1_0_X
void PNGAPI
#else
void /* private */
#endif
png_zfree(voidpf png_ptr, voidpf ptr)
{
png_free((png_structp)png_ptr, (png_voidp)ptr);
}
/* Reset the CRC variable to 32 bits of 1's. Care must be taken
* in case CRC is > 32 bits to leave the top bits 0.
*/
void /* PRIVATE */
png_reset_crc(png_structp png_ptr)
{
png_ptr->crc = crc32(0, Z_NULL, 0);
}
/* Calculate the CRC over a section of data. We can only pass as
* much data to this routine as the largest single buffer size. We
* also check that this data will actually be used before going to the
* trouble of calculating it.
*/
void /* PRIVATE */
png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
{
int need_crc = 1;
if (png_ptr->chunk_name[0] & 0x20) /* ancillary */
{
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
need_crc = 0;
}
else /* critical */
{
if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
need_crc = 0;
}
if (need_crc)
png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
}
void PNGAPI
png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
int num)
{
png_debug(1, "in png_free_data\n");
if (png_ptr == NULL || info_ptr == NULL)
return;
#if defined(PNG_TEXT_SUPPORTED)
/* free text item num or (if num == -1) all text items */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
#else
if (mask & PNG_FREE_TEXT)
#endif
{
if (num != -1)
{
if (info_ptr->text && info_ptr->text[num].key)
{
png_free(png_ptr, info_ptr->text[num].key);
info_ptr->text[num].key = NULL;
}
}
else
{
int i;
for (i = 0; i < info_ptr->num_text; i++)
png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
png_free(png_ptr, info_ptr->text);
info_ptr->text = NULL;
info_ptr->num_text=0;
}
}
#endif
#if defined(PNG_tRNS_SUPPORTED)
/* free any tRNS entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
#else
if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
#endif
{
png_free(png_ptr, info_ptr->trans);
info_ptr->valid &= ~PNG_INFO_tRNS;
#ifndef PNG_FREE_ME_SUPPORTED
png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
#endif
info_ptr->trans = NULL;
}
#endif
#if defined(PNG_sCAL_SUPPORTED)
/* free any sCAL entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
#else
if (mask & PNG_FREE_SCAL)
#endif
{
#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
png_free(png_ptr, info_ptr->scal_s_width);
png_free(png_ptr, info_ptr->scal_s_height);
info_ptr->scal_s_width = NULL;
info_ptr->scal_s_height = NULL;
#endif
info_ptr->valid &= ~PNG_INFO_sCAL;
}
#endif
#if defined(PNG_pCAL_SUPPORTED)
/* free any pCAL entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
#else
if (mask & PNG_FREE_PCAL)
#endif
{
png_free(png_ptr, info_ptr->pcal_purpose);
png_free(png_ptr, info_ptr->pcal_units);
info_ptr->pcal_purpose = NULL;
info_ptr->pcal_units = NULL;
if (info_ptr->pcal_params != NULL)
{
int i;
for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
{
png_free(png_ptr, info_ptr->pcal_params[i]);
info_ptr->pcal_params[i]=NULL;
}
png_free(png_ptr, info_ptr->pcal_params);
info_ptr->pcal_params = NULL;
}
info_ptr->valid &= ~PNG_INFO_pCAL;
}
#endif
#if defined(PNG_iCCP_SUPPORTED)
/* free any iCCP entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
#else
if (mask & PNG_FREE_ICCP)
#endif
{
png_free(png_ptr, info_ptr->iccp_name);
png_free(png_ptr, info_ptr->iccp_profile);
info_ptr->iccp_name = NULL;
info_ptr->iccp_profile = NULL;
info_ptr->valid &= ~PNG_INFO_iCCP;
}
#endif
#if defined(PNG_sPLT_SUPPORTED)
/* free a given sPLT entry, or (if num == -1) all sPLT entries */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
#else
if (mask & PNG_FREE_SPLT)
#endif
{
if (num != -1)
{
if(info_ptr->splt_palettes)
{
png_free(png_ptr, info_ptr->splt_palettes[num].name);
png_free(png_ptr, info_ptr->splt_palettes[num].entries);
info_ptr->splt_palettes[num].name = NULL;
info_ptr->splt_palettes[num].entries = NULL;
}
}
else
{
if(info_ptr->splt_palettes_num)
{
int i;
for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
png_free(png_ptr, info_ptr->splt_palettes);
info_ptr->splt_palettes = NULL;
info_ptr->splt_palettes_num = 0;
}
info_ptr->valid &= ~PNG_INFO_sPLT;
}
}
#endif
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
#else
if (mask & PNG_FREE_UNKN)
#endif
{
if (num != -1)
{
if(info_ptr->unknown_chunks)
{
png_free(png_ptr, info_ptr->unknown_chunks[num].data);
info_ptr->unknown_chunks[num].data = NULL;
}
}
else
{
int i;
if(info_ptr->unknown_chunks_num)
{
for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
png_free(png_ptr, info_ptr->unknown_chunks);
info_ptr->unknown_chunks = NULL;
info_ptr->unknown_chunks_num = 0;
}
}
}
#endif
#if defined(PNG_hIST_SUPPORTED)
/* free any hIST entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_HIST) & info_ptr->free_me)
#else
if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
#endif
{
png_free(png_ptr, info_ptr->hist);
info_ptr->hist = NULL;
info_ptr->valid &= ~PNG_INFO_hIST;
#ifndef PNG_FREE_ME_SUPPORTED
png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
#endif
}
#endif
/* free any PLTE entry that was internally allocated */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
#else
if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
#endif
{
png_zfree(png_ptr, info_ptr->palette);
info_ptr->palette = NULL;
info_ptr->valid &= ~PNG_INFO_PLTE;
#ifndef PNG_FREE_ME_SUPPORTED
png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
#endif
info_ptr->num_palette = 0;
}
#if defined(PNG_INFO_IMAGE_SUPPORTED)
/* free any image bits attached to the info structure */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
#else
if (mask & PNG_FREE_ROWS)
#endif
{
if(info_ptr->row_pointers)
{
int row;
for (row = 0; row < (int)info_ptr->height; row++)
{
png_free(png_ptr, info_ptr->row_pointers[row]);
info_ptr->row_pointers[row]=NULL;
}
png_free(png_ptr, info_ptr->row_pointers);
info_ptr->row_pointers=NULL;
}
info_ptr->valid &= ~PNG_INFO_IDAT;
}
#endif
#ifdef PNG_FREE_ME_SUPPORTED
if(num == -1)
info_ptr->free_me &= ~mask;
else
info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
#endif
}
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
int PNGAPI
png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
{
/* check chunk_name and return "keep" value if it's on the list, else 0 */
int i;
png_bytep p;
if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
return 0;
p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
for (i = png_ptr->num_chunk_list; i; i--, p-=5)
if (!png_memcmp(chunk_name, p, 4))
return ((int)*(p+4));
return 0;
}
#endif
void png_info_init(png_info *info_ptr)
{
memset(info_ptr, 0, sizeof(png_info));
}
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