www.pudn.com > transparentdib.zip > png.c
/* png.c - location for general purpose libpng functions
*
* libpng version 1.0.12 - June 8, 2001
* Copyright (c) 1998-2001 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_12 Your_png_h_is_not_version_1_0_12;
/* 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] = "1.0.12";
/* 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
/* 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.
*/
void PNGAPI
png_set_sig_bytes(png_structp png_ptr, int num_bytes)
{
png_debug(1, "in png_set_sig_bytes\n");
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 (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)));
}
/* (Obsolete) function to check signature bytes. It does not allow one
* to check a partial signature. This function might be removed in the
* future - use png_sig_cmp(). Returns true (nonzero) if the file is a PNG.
*/
int PNGAPI
png_check_sig(png_bytep sig, int num)
{
return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
}
/* Function to allocate memory for zlib and clear it to 0. */
voidpf /* PRIVATE */
png_zalloc(voidpf png_ptr, uInt items, uInt size)
{
png_uint_32 num_bytes = (png_uint_32)items * size;
png_voidp ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
#ifndef PNG_NO_ZALLOC_ZERO
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 */
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(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\n");
if(png_ptr == NULL) return (NULL);
#ifdef PNG_USER_MEM_SUPPORTED
if ((info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
png_ptr->malloc_fn, png_ptr->mem_ptr)) != NULL)
#else
if ((info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO)) != NULL)
#endif
{
png_info_init_3(&info_ptr, 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;
png_debug(1, "in png_destroy_info_struct\n");
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 = (png_infop)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.
*/
#undef png_info_init
void PNGAPI
png_info_init(png_infop info_ptr)
{
/* We only come here via pre-1.0.12-compiled applications */
png_info_init_3(&info_ptr, 0);
}
void PNGAPI
png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
{
png_infop info_ptr = *ptr_ptr;
png_debug(1, "in png_info_init_3\n");
if(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, 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\n");
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\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;
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;
}
#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;
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
}
/* 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\n");
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->chunk_list=NULL;
png_ptr->num_chunk_list=0;
}
#endif
png_info_init_3(&info_ptr, sizeof(png_info));
}
/* 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)
{
return (png_ptr->io_ptr);
}
#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\n");
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->time_buffer == NULL)
{
png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
sizeof(char)));
}
#if defined(_WIN32_WCE)
{
wchar_t time_buf[29];
wsprintf(time_buf, TEXT("%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);
WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
NULL, NULL);
}
#else
#ifdef USE_FAR_KEYWORD
{
char near_time_buf[29];
sprintf(near_time_buf, "%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*sizeof(char));
}
#else
sprintf(png_ptr->time_buffer, "%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
#endif /* _WIN32_WCE */
return ((png_charp)png_ptr->time_buffer);
}
#endif /* PNG_TIME_RFC1123_SUPPORTED */
#if 0
/* Signature string for a PNG file. */
png_bytep PNGAPI
png_sig_bytes(void)
{
return ((png_bytep)"\211\120\116\107\015\012\032\012");
}
#endif
png_charp PNGAPI
png_get_copyright(png_structp png_ptr)
{
if (png_ptr != NULL || png_ptr == NULL) /* silence compiler warning */
return ((png_charp) "\n libpng version 1.0.12 - June 8, 2001\n\
Copyright (c) 1998-2001 Glenn Randers-Pehrson\n\
Copyright (c) 1996, 1997 Andreas Dilger\n\
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.\n");
return ((png_charp) "");
}
/* 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.
*/
png_charp PNGAPI
png_get_libpng_ver(png_structp png_ptr)
{
/* Version of *.c files used when building libpng */
if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
return((png_charp) "1.0.12");
return((png_charp) "1.0.12");
}
png_charp PNGAPI
png_get_header_ver(png_structp png_ptr)
{
/* Version of *.h files used when building libpng */
if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
return((png_charp) PNG_LIBPNG_VER_STRING);
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 */
if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
return((png_charp) PNG_HEADER_VERSION_STRING);
return((png_charp) PNG_HEADER_VERSION_STRING);
}
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
int /* PRIVATE */
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)
{
return (inflateReset(&png_ptr->zstream));
}
/* 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) 10012L);
}
/* this function was added to libpng 1.2.0 */
#if !defined(PNG_USE_PNGGCCRD) && \
!(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
int PNGAPI
png_mmx_support(void)
{
return -1;
}
#endif