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02a5e33061
libpng/png.c
Glenn Randers-Pehrson 02a5e33061 Imported from libpng-1.4.0beta40.tar
2009-04-06 16:10:41 -05:00

859 lines
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/* png.c - location for general purpose libpng functions
*
* Last changed in libpng 1.4.0 [November 25, 2008]
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1998-2008 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_NO_EXTERN
#include "png.h"
#include "pngpriv.h"
/* Generate a compiler error if there is an old png.h in the search path. */
typedef version_1_4_0beta40 Your_png_h_is_not_version_1_4_0beta40;
/* 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 */
PNG_CONST char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
#ifdef PNG_READ_SUPPORTED
/* png_sig was changed to a function in version 1.0.5c */
/* Place to hold the signature string for a PNG file. */
PNG_CONST png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
#endif /* PNG_READ_SUPPORTED */
/* 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;
#ifdef PNG_READ_SUPPORTED
/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* start of interlace block */
PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
/* offset to next interlace block */
PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
/* start of interlace block in the y direction */
PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
/* offset to next interlace block in the y direction */
PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
/* Height of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
*/
/* Mask to determine which pixels are valid in a pass */
PNG_CONST int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
/* Mask to determine which pixels to overwrite while displaying */
PNG_CONST int FARDATA png_pass_dsp_mask[]
= {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
#endif /* PNG_READ_SUPPORTED */
#endif /* PNG_USE_GLOBAL_ARRAYS */
/* Tells libpng that we have already handled the first "num_bytes" bytes
* of the PNG file signature. If the PNG data is embedded into another
* stream we can set num_bytes = 8 so that libpng will not attempt to read
* or write any of the magic bytes before it starts on the IHDR.
*/
#ifdef PNG_READ_SUPPORTED
void PNGAPI
png_set_sig_bytes(png_structp png_ptr, int num_bytes)
{
if (png_ptr == NULL) return;
png_debug(1, "in png_set_sig_bytes");
if (num_bytes > 8)
png_error(png_ptr, "Too many bytes for PNG signature");
png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
}
/* 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 (-1);
if (start > 7)
return (-1);
if (start + num_to_check > 8)
num_to_check = 8 - start;
return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
}
#endif /* PNG_READ_SUPPORTED */
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
/* Function to allocate memory for zlib and clear it to 0. */
voidpf /* private */
png_zalloc(voidpf png_ptr, uInt items, uInt size)
{
png_voidp ptr;
png_structp p=(png_structp)png_ptr;
png_uint_32 save_flags=p->flags;
png_alloc_size_t num_bytes;
if (png_ptr == NULL) return (NULL);
if (items > PNG_UINT_32_MAX/size)
{
png_warning (p, "Potential overflow in png_zalloc()");
return (NULL);
}
num_bytes = (png_alloc_size_t)items * size;
p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
p->flags=save_flags;
return ((voidpf)ptr);
}
/* function to free memory for zlib */
void /* private */
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);
}
/* Allocate the memory for an info_struct for the application. We don't
* really need the png_ptr, but it could potentially be useful in the
* future. This should be used in favour of malloc(png_sizeof(png_info))
* and png_info_init() so that applications that want to use a shared
* libpng don't have to be recompiled if png_info changes size.
*/
png_infop PNGAPI
png_create_info_struct(png_structp png_ptr)
{
png_infop info_ptr;
png_debug(1, "in png_create_info_struct");
if (png_ptr == NULL) return (NULL);
#ifdef PNG_USER_MEM_SUPPORTED
info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
png_ptr->malloc_fn, png_ptr->mem_ptr);
#else
info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
#endif
if (info_ptr != NULL)
png_info_init_3(&info_ptr, png_sizeof(png_info));
return (info_ptr);
}
/* This function frees the memory associated with a single info struct.
* Normally, one would use either png_destroy_read_struct() or
* png_destroy_write_struct() to free an info struct, but this may be
* useful for some applications.
*/
void PNGAPI
png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
{
png_infop info_ptr = NULL;
if (png_ptr == NULL) return;
png_debug(1, "in png_destroy_info_struct");
if (info_ptr_ptr != NULL)
info_ptr = *info_ptr_ptr;
if (info_ptr != NULL)
{
png_info_destroy(png_ptr, info_ptr);
#ifdef PNG_USER_MEM_SUPPORTED
png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
png_ptr->mem_ptr);
#else
png_destroy_struct((png_voidp)info_ptr);
#endif
*info_ptr_ptr = NULL;
}
}
/* Initialize the info structure. This is now an internal function (0.89)
* and applications using it are urged to use png_create_info_struct()
* instead.
*/
void PNGAPI
png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
{
png_infop info_ptr = *ptr_ptr;
if (info_ptr == NULL) return;
png_debug(1, "in png_info_init_3");
if (png_sizeof(png_info) > png_info_struct_size)
{
png_destroy_struct(info_ptr);
info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
*ptr_ptr = info_ptr;
}
/* set everything to 0 */
png_memset(info_ptr, 0, png_sizeof(png_info));
}
#ifdef PNG_FREE_ME_SUPPORTED
void PNGAPI
png_data_freer(png_structp png_ptr, png_infop info_ptr,
int freer, png_uint_32 mask)
{
png_debug(1, "in png_data_freer");
if (png_ptr == NULL || info_ptr == NULL)
return;
if (freer == PNG_DESTROY_WILL_FREE_DATA)
info_ptr->free_me |= mask;
else if (freer == PNG_USER_WILL_FREE_DATA)
info_ptr->free_me &= ~mask;
else
png_warning(png_ptr,
"Unknown freer parameter in png_data_freer");
}
#endif
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");
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->trans = NULL;
info_ptr->valid &= ~PNG_INFO_tRNS;
#ifndef PNG_FREE_ME_SUPPORTED
png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
#endif
}
#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)
if (png_ptr->unknown_chunk.data)
{
png_free(png_ptr, png_ptr->unknown_chunk.data);
png_ptr->unknown_chunk.data = NULL;
}
#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]);
}
png_free(png_ptr, info_ptr->row_pointers);
}
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
}
/* This is an internal routine to free any memory that the info struct is
* pointing to before re-using it or freeing the struct itself. Recall
* that png_free() checks for NULL pointers for us.
*/
void /* PRIVATE */
png_info_destroy(png_structp png_ptr, png_infop info_ptr)
{
png_debug(1, "in png_info_destroy");
png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
if (png_ptr->num_chunk_list)
{
png_free(png_ptr, png_ptr->chunk_list);
png_ptr->num_chunk_list = 0;
}
#endif
png_info_init_3(&info_ptr, png_sizeof(png_info));
}
#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
/* This function returns a pointer to the io_ptr associated with the user
* functions. The application should free any memory associated with this
* pointer before png_write_destroy() or png_read_destroy() are called.
*/
png_voidp PNGAPI
png_get_io_ptr(png_structp png_ptr)
{
if (png_ptr == NULL) return (NULL);
return (png_ptr->io_ptr);
}
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
#if !defined(PNG_NO_STDIO)
/* Initialize the default input/output functions for the PNG file. If you
* use your own read or write routines, you can call either png_set_read_fn()
* or png_set_write_fn() instead of png_init_io(). If you have defined
* PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
* necessarily available.
*/
void PNGAPI
png_init_io(png_structp png_ptr, png_FILE_p fp)
{
png_debug(1, "in png_init_io");
if (png_ptr == NULL) return;
png_ptr->io_ptr = (png_voidp)fp;
}
#endif
#if defined(PNG_TIME_RFC1123_SUPPORTED)
/* Convert the supplied time into an RFC 1123 string suitable for use in
* a "Creation Time" or other text-based time string.
*/
png_charp PNGAPI
png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
{
static PNG_CONST char short_months[12][4] =
{"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
if (png_ptr == NULL) return (NULL);
if (png_ptr->time_buffer == NULL)
{
png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
png_sizeof(char)));
}
#ifdef USE_FAR_KEYWORD
{
char near_time_buf[29];
png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000",
ptime->day % 32, short_months[(ptime->month - 1) % 12],
ptime->year, ptime->hour % 24, ptime->minute % 60,
ptime->second % 61);
png_memcpy(png_ptr->time_buffer, near_time_buf,
29*png_sizeof(char));
}
#else
png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000",
ptime->day % 32, short_months[(ptime->month - 1) % 12],
ptime->year, ptime->hour % 24, ptime->minute % 60,
ptime->second % 61);
#endif
return ((png_charp)png_ptr->time_buffer);
}
#endif /* PNG_TIME_RFC1123_SUPPORTED */
#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
png_charp PNGAPI
png_get_copyright(png_structp png_ptr)
{
png_ptr = png_ptr; /* silence compiler warning about unused png_ptr */
#ifdef PNG_STRING_COPYRIGHT
return PNG_STRING_COPYRIGHT
#else
#ifdef __STDC__
return ((png_charp) PNG_STRING_NEWLINE \
"libpng version x 1.4.0beta40 - November 25, 2008" PNG_STRING_NEWLINE \
"Copyright (c) 1998-2008 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
"Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
"Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
PNG_STRING_NEWLINE);
#else
return ((png_charp) "libpng version 1.4.0beta40 - November 25, 2008\
Copyright (c) 1998-2008 Glenn Randers-Pehrson\
Copyright (c) 1996-1997 Andreas Dilger\
Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.");
#endif
#endif
}
/* The following return the library version as a short string in the
* format 1.0.0 through 99.99.99zz. To get the version of *.h files
* used with your application, print out PNG_LIBPNG_VER_STRING, which
* is defined in png.h.
* Note: now there is no difference between png_get_libpng_ver() and
* png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
* it is guaranteed that png.c uses the correct version of png.h.
*/
png_charp PNGAPI
png_get_libpng_ver(png_structp png_ptr)
{
/* Version of *.c files used when building libpng */
png_ptr = png_ptr; /* silence compiler warning about unused png_ptr */
return ((png_charp) PNG_LIBPNG_VER_STRING);
}
png_charp PNGAPI
png_get_header_ver(png_structp png_ptr)
{
/* Version of *.h files used when building libpng */
png_ptr = png_ptr; /* silence compiler warning about unused png_ptr */
return ((png_charp) PNG_LIBPNG_VER_STRING);
}
png_charp PNGAPI
png_get_header_version(png_structp png_ptr)
{
/* Returns longer string containing both version and date */
png_ptr = png_ptr; /* silence compiler warning about unused png_ptr */
#ifdef __STDC__
return ((png_charp) PNG_HEADER_VERSION_STRING
#ifndef PNG_READ_SUPPORTED
" (NO READ SUPPORT)"
#endif
PNG_STRING_NEWLINE);
#else
return ((png_charp) PNG_HEADER_VERSION_STRING);
#endif
}
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
#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
/* This function, added to libpng-1.0.6g, is untested. */
int PNGAPI
png_reset_zstream(png_structp png_ptr)
{
if (png_ptr == NULL) return Z_STREAM_ERROR;
return (inflateReset(&png_ptr->zstream));
}
#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
/* This function was added to libpng-1.0.7 */
png_uint_32 PNGAPI
png_access_version_number(void)
{
/* Version of *.c files used when building libpng */
return((png_uint_32) PNG_LIBPNG_VER);
}
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
#ifdef PNG_SIZE_T
/* Added at libpng version 1.2.6 */
PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
png_size_t PNGAPI
png_convert_size(size_t size)
{
if (size > (png_size_t)-1)
PNG_ABORT(); /* We haven't got access to png_ptr, so no png_error() */
return ((png_size_t)size);
}
#endif /* PNG_SIZE_T */
/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
#if defined(PNG_cHRM_SUPPORTED)
/*
Multiply two 32-bit numbers, V1 and V2, using 32-bit
arithmetic, to produce a 64 bit result in the HI/LO words.
A B
x C D
------
AD || BD
AC || CB || 0
where A and B are the high and low 16-bit words of V1,
C and D are the 16-bit words of V2, AD is the product of
A and D, and X || Y is (X << 16) + Y.
*/
void png_64bit_product (long v1, long v2, unsigned long *hi_product,
unsigned long *lo_product)
{
int a, b, c, d;
long lo, hi, x, y;
a = (v1 >> 16) & 0xffff;
b = v1 & 0xffff;
c = (v2 >> 16) & 0xffff;
d = v2 & 0xffff;
lo = b * d; /* BD */
x = a * d + c * b; /* AD + CB */
y = ((lo >> 16) & 0xffff) + x;
lo = (lo & 0xffff) | ((y & 0xffff) << 16);
hi = (y >> 16) & 0xffff;
hi += a * c; /* AC */
*hi_product = (unsigned long)hi;
*lo_product = (unsigned long)lo;
}
int /* private */
png_check_cHRM_fixed(png_structp png_ptr,
png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
png_fixed_point blue_x, png_fixed_point blue_y)
{
int ret = 1;
unsigned long xy_hi,xy_lo,yx_hi,yx_lo;
png_debug(1, "in function png_check_cHRM_fixed");
if (png_ptr == NULL)
return 0;
if (white_x < 0 || white_y <= 0 ||
red_x < 0 || red_y < 0 ||
green_x < 0 || green_y < 0 ||
blue_x < 0 || blue_y < 0)
{
png_warning(png_ptr,
"Ignoring attempt to set negative chromaticity value");
ret = 0;
}
if (white_x > (png_fixed_point) PNG_UINT_31_MAX ||
white_y > (png_fixed_point) PNG_UINT_31_MAX ||
red_x > (png_fixed_point) PNG_UINT_31_MAX ||
red_y > (png_fixed_point) PNG_UINT_31_MAX ||
green_x > (png_fixed_point) PNG_UINT_31_MAX ||
green_y > (png_fixed_point) PNG_UINT_31_MAX ||
blue_x > (png_fixed_point) PNG_UINT_31_MAX ||
blue_y > (png_fixed_point) PNG_UINT_31_MAX )
{
png_warning(png_ptr,
"Ignoring attempt to set chromaticity value exceeding 21474.83");
ret = 0;
}
if (white_x + white_y > 100000L)
{
png_warning(png_ptr, "Invalid cHRM white point");
ret = 0;
}
if (red_x + red_y > 100000L)
{
png_warning(png_ptr, "Invalid cHRM red point");
ret = 0;
}
if (green_x + green_y > 100000L)
{
png_warning(png_ptr, "Invalid cHRM green point");
ret = 0;
}
if (blue_x + blue_y > 100000L)
{
png_warning(png_ptr, "Invalid cHRM blue point");
ret = 0;
}
png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo);
png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo);
if (xy_hi == yx_hi && xy_lo == yx_lo)
{
png_warning(png_ptr,
"Ignoring attempt to set cHRM RGB triangle with zero area");
ret = 0;
}
return ret;
}
#endif /* PNG_cHRM_SUPPORTED */
#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
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