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Imported from libpng-0.97.tar

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This commit is contained in:
Glenn Randers-Pehrson
1998-01-01 07:13:13 -06:00
parent 47a0c422ca
commit b6ce43d6ff
24 changed files with 1297 additions and 763 deletions
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154
png.c
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@@ -1,27 +1,29 @@
/* png.c - location for general purpose png functions
libpng 1.0 beta 6 - version 0.96
For conditions of distribution and use, see copyright notice in png.h
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
Copyright (c) 1996, 1997 Andreas Dilger
May 12, 1997
*/
/* png.c - location for general purpose libpng functions
*
* libpng 1.00.97
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
* Copyright (c) 1996, 1997 Andreas Dilger
* May 28, 1997
*/
#define PNG_INTERNAL
#define PNG_NO_EXTERN
#include "png.h"
/* Version information for C files. This had better match the version
string defined in png.h */
char png_libpng_ver[] = "0.95";
* string defined in png.h.
*/
char png_libpng_ver[] = "1.00.97";
/* Place to hold the signiture string for a PNG file. */
png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
/* constant strings for known chunk types. If you need to add a chunk,
add a string holding the name here. If you want to make the code
portable to EBCDIC machines, use ASCII numbers, not characters. */
/* Constant strings for known chunk types. If you need to add a chunk,
* add a string holding the name here. If you want to make the code
* portable to EBCDIC machines, use ASCII numbers, not characters.
*/
png_byte FARDATA png_IHDR[5] = { 73, 72, 68, 82, '\0'};
png_byte FARDATA png_IDAT[5] = { 73, 68, 65, 84, '\0'};
png_byte FARDATA png_IEND[5] = { 73, 69, 78, 68, '\0'};
@@ -34,6 +36,7 @@ png_byte FARDATA png_oFFs[5] = {111, 70, 70, 115, '\0'};
png_byte FARDATA png_pCAL[5] = {112, 67, 65, 76, '\0'};
png_byte FARDATA png_pHYs[5] = {112, 72, 89, 115, '\0'};
png_byte FARDATA png_sBIT[5] = {115, 66, 73, 84, '\0'};
png_byte FARDATA png_sRGB[5] = {115, 82, 71, 66, '\0'};
png_byte FARDATA png_tEXt[5] = {116, 69, 88, 116, '\0'};
png_byte FARDATA png_tIME[5] = {116, 73, 77, 69, '\0'};
png_byte FARDATA png_tRNS[5] = {116, 82, 78, 83, '\0'};
@@ -53,22 +56,20 @@ int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
/* offset to next interlace block in the y direction */
int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
/* width of interlace block */
/* this is not currently used - if you need it, uncomment it here and
in png.h
/* Width of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
*/
/* height of interlace block */
/* this is not currently used - if you need it, uncomment it here and
in png.h
/* Height of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
*/
/* mask to determine which pixels are valid in a pass */
/* Mask to determine which pixels are valid in a pass */
int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
/* mask to determine which pixels to overwrite while displaying */
/* Mask to determine which pixels to overwrite while displaying */
int FARDATA png_pass_dsp_mask[] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
@@ -113,8 +114,9 @@ png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
}
/* (Obsolete) function to check signature bytes. It does not allow one
to check a partial signature. This function will be removed in the
future - use png_sig_cmp(). */
* to check a partial signature. This function will be removed in the
* future - use png_sig_cmp().
*/
int
png_check_sig(png_bytep sig, int num)
{
@@ -151,78 +153,19 @@ png_zfree(voidpf png_ptr, voidpf 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. */
* in case CRC is > 32 bits to leave the top bits 0.
*/
void
png_reset_crc(png_structp png_ptr)
{
/* set CRC to all 1's */
#ifdef PNG_USE_OWN_CRC
png_ptr->crc = 0xffffffffL;
#else
png_ptr->crc = crc32(0, Z_NULL, 0);
#endif
}
#ifdef PNG_USE_OWN_CRC
/* Table of CRCs of all 8-bit messages. By default, we use the tables made
by zlib, to save some memory. If you wish to png_malloc() this
table, turn this into a pointer, and png_malloc() it in make_crc_table().
You may then want to hook it into png_struct and free it with the
destroy functions. Another alternative is to pre-fill the table. */
static png_uint_32 crc_table[256];
/* Flag: has the table been computed? Initially false. */
static int crc_table_computed = 0;
/* make the table for a fast crc */
static void
make_crc_table(void)
{
png_uint_32 c;
int n, k;
for (n = 0; n < 256; n++)
{
c = (png_uint_32)n;
for (k = 0; k < 8; k++)
c = c & 1 ? 0xedb88320L ^ (c >> 1) : c >> 1;
crc_table[n] = c;
}
crc_table_computed = 1;
}
/* Update a running CRC with the bytes buf[0..len-1] - the CRC should be
initialized to all 1's, and the transmitted value is the 1's complement
of the final running CRC. */
static png_uint_32
update_crc(png_uint_32 crc, png_bytep buf, png_size_t len)
{
png_uint_32 c;
png_bytep p;
png_uint_32 n;
c = crc;
p = buf;
n = len;
if (!crc_table_computed)
{
make_crc_table();
}
if (n > 0) do
{
c = crc_table[(png_byte)((c ^ (*p++)) & 0xff)] ^ (c >> 8);
} while (--n);
return c;
}
#endif /* PNG_USE_OWN_CRC */
/* 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. */
* 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
png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
{
@@ -241,18 +184,15 @@ png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
}
if (need_crc)
#ifdef PNG_USE_OWN_CRC
png_ptr->crc = update_crc(png_ptr->crc, ptr, length);
#else
png_ptr->crc = crc32(png_ptr->crc, ptr, length);
#endif
}
/* 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. */
* 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
png_create_info_struct(png_structp png_ptr)
{
@@ -268,9 +208,10 @@ png_create_info_struct(png_structp png_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. */
* 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
png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
{
@@ -290,8 +231,9 @@ png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
}
/* 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. */
* and applications using it are urged to use png_create_info_struct()
* instead.
*/
void
png_info_init(png_infop info_ptr)
{
@@ -337,8 +279,9 @@ png_info_destroy(png_structp png_ptr, png_infop info_ptr)
}
/* 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. */
* functions. The application should free any memory associated with this
* pointer before png_write_destroy() or png_read_destroy() are called.
*/
png_voidp
png_get_io_ptr(png_structp png_ptr)
{
@@ -347,8 +290,9 @@ png_get_io_ptr(png_structp png_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(). */
* 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().
*/
void
png_init_io(png_structp png_ptr, FILE *fp)
{