/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/* png.c - location for general purpose libpng functions
*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file and, per its terms, should not be removed:
*
* Last changed in libpng 1.5.4 [July 7, 2011]
* Copyright (c) 1998-2011 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.)
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*/
#include "pngpriv.h"
/* Generate a compiler error if there is an old png.h in the search path. */
/* 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
{
return;
if (num_bytes > 8)
}
/* 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
{
if (num_to_check > 8)
num_to_check = 8;
else if (num_to_check < 1)
return (-1);
if (start > 7)
return (-1);
}
#endif /* PNG_READ_SUPPORTED */
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
/* Function to allocate memory for zlib */
{
return (NULL);
{
png_warning (p, "Potential overflow in png_zalloc()");
return (NULL);
}
p->flags=save_flags;
}
/* Function to free memory for zlib */
void /* PRIVATE */
{
}
/* 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 */
{
}
/* 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 */
{
{
need_crc = 0;
}
else /* critical */
{
need_crc = 0;
}
if (need_crc)
}
/* Check a user supplied version number, called from both read and write
* functions that create a png_struct
*/
int
{
if (user_png_ver)
{
int i = 0;
do
{
if (user_png_ver[i] != png_libpng_ver[i])
} while (png_libpng_ver[i++]);
}
else
{
/* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
* we must recompile any applications that use any older library version.
* For versions after libpng 1.0, we will be compatible, so we need
* only check the first digit.
*/
{
#ifdef PNG_WARNINGS_SUPPORTED
char m[128];
png_warning(png_ptr, m);
#endif
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
#endif
return 0;
}
}
/* Success return. */
return 1;
}
/* 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.
*/
{
return (NULL);
#ifdef PNG_USER_MEM_SUPPORTED
#else
#endif
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
{
return;
if (info_ptr_ptr != NULL)
info_ptr = *info_ptr_ptr;
{
#ifdef PNG_USER_MEM_SUPPORTED
#else
#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
{
return;
{
}
/* Set everything to 0 */
}
void PNGAPI
{
return;
if (freer == PNG_DESTROY_WILL_FREE_DATA)
else if (freer == PNG_USER_WILL_FREE_DATA)
else
"Unknown freer parameter in png_data_freer");
}
void PNGAPI
int num)
{
return;
#ifdef PNG_TEXT_SUPPORTED
/* Free text item num or (if num == -1) all text items */
{
if (num != -1)
{
{
}
}
else
{
int i;
}
}
#endif
#ifdef PNG_tRNS_SUPPORTED
/* Free any tRNS entry */
{
}
#endif
#ifdef PNG_sCAL_SUPPORTED
/* Free any sCAL entry */
{
}
#endif
#ifdef PNG_pCAL_SUPPORTED
/* Free any pCAL entry */
{
{
int i;
for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
{
}
}
}
#endif
#ifdef PNG_iCCP_SUPPORTED
/* Free any iCCP entry */
{
}
#endif
#ifdef PNG_sPLT_SUPPORTED
/* Free a given sPLT entry, or (if num == -1) all sPLT entries */
{
if (num != -1)
{
if (info_ptr->splt_palettes)
{
}
}
else
{
if (info_ptr->splt_palettes_num)
{
int i;
for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
info_ptr->splt_palettes_num = 0;
}
}
}
#endif
#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
{
}
{
if (num != -1)
{
if (info_ptr->unknown_chunks)
{
}
}
else
{
int i;
if (info_ptr->unknown_chunks_num)
{
for (i = 0; i < info_ptr->unknown_chunks_num; i++)
info_ptr->unknown_chunks_num = 0;
}
}
}
#endif
#ifdef PNG_hIST_SUPPORTED
/* Free any hIST entry */
{
}
#endif
/* Free any PLTE entry that was internally allocated */
{
info_ptr->num_palette = 0;
}
#ifdef PNG_INFO_IMAGE_SUPPORTED
/* Free any image bits attached to the info structure */
{
if (info_ptr->row_pointers)
{
int row;
{
}
}
}
#endif
if (num != -1)
mask &= ~PNG_FREE_MUL;
}
/* 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 */
{
if (png_ptr->num_chunk_list)
{
png_ptr->num_chunk_list = 0;
}
#endif
}
#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.
*/
{
return (NULL);
}
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
# ifdef PNG_STDIO_SUPPORTED
* 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
{
return;
}
# endif
# ifdef 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.
*/
{
{"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
return (NULL);
{
APPEND(' ');
APPEND(' ');
APPEND(' ');
APPEND(':');
APPEND(':');
}
return png_ptr->time_buffer;
}
# endif /* PNG_TIME_RFC1123_SUPPORTED */
#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
{
#ifdef PNG_STRING_COPYRIGHT
return PNG_STRING_COPYRIGHT
#else
# ifdef __STDC__
return PNG_STRING_NEWLINE \
"libpng version 1.5.4 - July 7, 2011" PNG_STRING_NEWLINE \
"Copyright (c) 1998-2011 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." \
# else
return "libpng version 1.5.4 - July 7, 2011\
Copyright (c) 1998-2011 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,
*/
{
/* Version of *.c files used when building libpng */
return png_get_header_ver(png_ptr);
}
{
/* Version of *.h files used when building libpng */
return PNG_LIBPNG_VER_STRING;
}
{
/* Returns longer string containing both version and date */
#ifdef __STDC__
return PNG_HEADER_VERSION_STRING
# ifndef PNG_READ_SUPPORTED
" (NO READ SUPPORT)"
# endif
#else
return PNG_HEADER_VERSION_STRING;
#endif
}
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
# ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
int PNGAPI
{
/* Check chunk_name and return "keep" value if it's on the list, else 0 */
int i;
png_bytep p;
return 0;
return ((int)*(p + 4));
return 0;
}
# endif
#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
#ifdef PNG_READ_SUPPORTED
/* This function, added to libpng-1.0.6g, is untested. */
int PNGAPI
{
return Z_STREAM_ERROR;
}
#endif /* PNG_READ_SUPPORTED */
/* This function was added to libpng-1.0.7 */
{
/* 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_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) */
# ifdef PNG_CHECK_cHRM_SUPPORTED
int /* PRIVATE */
{
return 0;
/* (x,y,z) values are first limited to 0..100000 (PNG_FP_1), the white
* y must also be greater than 0. To test for the upper limit calculate
* (PNG_FP_1-y) - x must be <= to this for z to be >= 0 (and the expression
* cannot overflow.) At this point we know x and y are >= 0 and (x+y) is
* <= PNG_FP_1. The previous test on PNG_MAX_UINT_31 is removed because it
* pointless (and it produces compiler warnings!)
*/
{
"Ignoring attempt to set negative chromaticity value");
ret = 0;
}
/* And (x+y) must be <= PNG_FP_1 (so z is >= 0) */
{
ret = 0;
}
{
ret = 0;
}
{
ret = 0;
}
{
ret = 0;
}
{
"Ignoring attempt to set cHRM RGB triangle with zero area");
ret = 0;
}
return ret;
}
# endif /* PNG_CHECK_cHRM_SUPPORTED */
void /* PRIVATE */
int filter_type)
{
int error = 0;
/* Check for width and height valid values */
if (width == 0)
{
error = 1;
}
if (height == 0)
{
error = 1;
}
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
# else
if (width > PNG_USER_WIDTH_MAX)
# endif
{
error = 1;
}
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
# else
if (height > PNG_USER_HEIGHT_MAX)
# endif
{
error = 1;
}
if (width > PNG_UINT_31_MAX)
{
error = 1;
}
if (height > PNG_UINT_31_MAX)
{
error = 1;
}
if (width > (PNG_UINT_32_MAX
>> 3) /* 8-byte RGBA pixels */
- 48 /* bigrowbuf hack */
- 1 /* filter byte */
- 7*8 /* rounding of width to multiple of 8 pixels */
- 8) /* extra max_pixel_depth pad */
/* Check other values */
{
error = 1;
}
{
error = 1;
}
((color_type == PNG_COLOR_TYPE_RGB ||
{
error = 1;
}
if (interlace_type >= PNG_INTERLACE_LAST)
{
error = 1;
}
{
error = 1;
}
# ifdef PNG_MNG_FEATURES_SUPPORTED
/* Accept filter_method 64 (intrapixel differencing) only if
* 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
* 2. Libpng did not read a PNG signature (this filter_method is only
* used in PNG datastreams that are embedded in MNG datastreams) and
* 3. The application called png_permit_mng_features with a mask that
* included PNG_FLAG_MNG_FILTER_64 and
* 4. The filter_method is 64 and
* 5. The color_type is RGB or RGBA
*/
if (filter_type != PNG_FILTER_TYPE_BASE)
{
(color_type == PNG_COLOR_TYPE_RGB ||
{
error = 1;
}
{
error = 1;
}
}
# else
if (filter_type != PNG_FILTER_TYPE_BASE)
{
error = 1;
}
# endif
if (error == 1)
}
#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
/* ASCII to fp functions */
/* Check an ASCII formated floating point value, see the more detailed
* comments in pngpriv.h
*/
/* The following is used internally to preserve the sticky flags */
int /* PRIVATE */
{
png_size_t i = *whereami;
while (i < size)
{
int type;
/* First find the type of the next character */
switch (string[i])
{
case 49: case 50: case 51: case 52:
case 53: case 54: case 55: case 56:
case 69:
default: goto PNG_FP_End;
}
/* Now deal with this type according to the current
* state, the type is arranged to not overlap the
* bits of the PNG_FP_STATE.
*/
{
case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
if (state & PNG_FP_SAW_ANY)
goto PNG_FP_End; /* not a part of the number */
break;
case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
/* Ok as trailer, ok as lead of fraction. */
goto PNG_FP_End;
else
break;
case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
break;
case PNG_FP_INTEGER + PNG_FP_SAW_E:
if ((state & PNG_FP_SAW_DIGIT) == 0)
goto PNG_FP_End;
break;
/* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
goto PNG_FP_End; ** no sign in fraction */
/* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
goto PNG_FP_End; ** Because SAW_DOT is always set */
case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
break;
case PNG_FP_FRACTION + PNG_FP_SAW_E:
/* This is correct because the trailing '.' on an
* integer is handled above - so we can only get here
* with the sequence ".E" (with no preceding digits).
*/
if ((state & PNG_FP_SAW_DIGIT) == 0)
goto PNG_FP_End;
break;
case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
if (state & PNG_FP_SAW_ANY)
goto PNG_FP_End; /* not a part of the number */
break;
/* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
goto PNG_FP_End; */
case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
break;
/* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
goto PNG_FP_End; */
default: goto PNG_FP_End; /* I.e. break 2 */
}
/* The character seems ok, continue. */
++i;
}
/* Here at the end, update the state and return the correct
* return code.
*/
*whereami = i;
return (state & PNG_FP_SAW_DIGIT) != 0;
}
/* The same but for a complete string. */
int
{
int state=0;
return state /* must be non-zero - see above */;
return 0; /* i.e. fail */
}
#endif /* pCAL or sCAL */
#ifdef PNG_READ_sCAL_SUPPORTED
# ifdef PNG_FLOATING_POINT_SUPPORTED
/* Utility used below - a simple accurate power of ten from an integral
* exponent.
*/
static double
{
int recip = 0;
double d = 1;
/* Handle negative exponent with a reciprocal at the end because
* 10 is exact whereas .1 is inexact in base 2
*/
if (power < 0)
{
if (power < DBL_MIN_10_EXP) return 0;
}
if (power > 0)
{
/* Decompose power bitwise. */
do
{
power >>= 1;
}
while (power > 0);
if (recip) d = 1/d;
}
/* else power is 0 and d is 1 */
return d;
}
/* Function to format a floating point value in ASCII with a given
* precision.
*/
void /* PRIVATE */
{
/* We use standard functions from math.h, but not printf because
* that would require stdio. The caller must supply a buffer of
* sufficient size or we will png_error. The tests on size and
* the space in ascii[] consumed are indicated below.
*/
if (precision < 1)
/* Enforce the limit of the implementation precision too. */
/* Basic sanity checks */
{
if (fp < 0)
{
--size;
}
{
/* First extract a base 10 exponent of the number,
* the calculation below rounds down when converting
* from base 2 to base 10 (multiply by log10(2) -
* 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
* be increased. Note that the arithmetic shift
* performs a floor() unlike C arithmetic - using a
* C multiply would break the following for negative
* exponents.
*/
/* Avoid underflow here. */
{
/* And this may overflow. */
else
break;
}
/* Normalize fp and correct exp_b10, after this fp is in the
* range [.1,1) and exp_b10 is both the exponent and the digit
* *before* which the decimal point should be inserted
* (starting with 0 for the first digit). Note that this
* works even if 10^exp_b10 is out of range because of the
* test on DBL_MAX above.
*/
/* Because of the code above fp may, at this point, be
* less than .1, this is ok because the code below can
* handle the leading zeros this generates, so no attempt
* is made to correct that here.
*/
{
/* Allow up to two leading zeros - this will not lengthen
* the number compared to using E-n.
*/
{
exp_b10 = 0; /* Dot added below before first output. */
}
else
czero = 0; /* No zeros to add */
/* Generate the digit list, stripping trailing zeros and
* inserting a '.' before a digit if the exponent is 0.
*/
cdigits = 0; /* Count of digits in list. */
do
{
double d;
fp *= 10;
/* Use modf here, not floor and subtract, so that
* the separation is done in one step. At the end
* of the loop don't break the number into parts so
* that the final digit is rounded.
*/
else
{
if (d > 9)
{
/* Rounding up to 10, handle that here. */
if (czero > 0)
{
--czero, d = 1;
}
else
{
while (cdigits > 0 && d > 9)
{
if (exp_b10 != (-1))
++exp_b10;
else if (ch == 46)
{
/* Advance exp_b10 to '1', so that the
* decimal point happens after the
* previous digit.
*/
exp_b10 = 1;
}
--cdigits;
}
/* Did we reach the beginning? If so adjust the
* exponent but take into account the leading
* decimal point.
*/
if (d > 9) /* cdigits == 0 */
{
if (exp_b10 == (-1))
{
/* Leading decimal point (plus zeros?), if
* we lose the decimal point here it must
* be reentered below.
*/
if (ch == 46)
/* Else lost a leading zero, so 'exp_b10' is
* still ok at (-1)
*/
}
else
++exp_b10;
/* In all cases we output a '1' */
d = 1;
}
}
}
fp = 0; /* Guarantees termination below. */
}
if (d == 0)
{
++czero;
}
else
{
/* Included embedded zeros in the digit count. */
clead = 0;
while (czero > 0)
{
/* exp_b10 == (-1) means we just output the decimal
* place - after the DP don't adjust 'exp_b10' any
* more!
*/
if (exp_b10 != (-1))
{
/* PLUS 1: TOTAL 4 */
--exp_b10;
}
}
if (exp_b10 != (-1))
{
above */
--exp_b10;
}
}
}
/* The total output count (max) is now 4+precision */
/* Check for an exponent, if we don't need one we are
* done and just need to terminate the string. At
* this point exp_b10==(-1) is effectively if flag - it got
* to '-1' because of the decrement after outputing
* the decimal point above (the exponent required is
* *not* -1!)
*/
{
/* The following only happens if we didn't output the
* leading zeros above for negative exponent, so this
* doest add to the digit requirement. Note that the
* two zeros here can only be output if the two leading
* zeros were *not* output, so this doesn't increase
* the output count.
*/
*ascii = 0;
/* Total buffer requirement (including the '\0') is
* 5+precision - see check at the start.
*/
return;
}
/* Here if an exponent is required, adjust size for
* the digits we output but did not count. The total
* digit output here so far is at most 1+precision - no
* decimal point and no leading or trailing zeros have
* been output.
*/
if (exp_b10 < 0)
{
}
cdigits = 0;
while (exp_b10 > 0)
{
exp_b10 /= 10;
}
/* Need another size check here for the exponent digits, so
* this need not be considered above.
*/
{
*ascii = 0;
return;
}
}
}
{
*ascii = 0;
return;
}
else
{
*ascii = 0;
return;
}
}
/* Here on buffer too small. */
}
# endif /* FLOATING_POINT */
# ifdef PNG_FIXED_POINT_SUPPORTED
/* Function to format a fixed point value in ASCII.
*/
void /* PRIVATE */
{
/* Require space for 10 decimal digits, a decimal point, a minus sign and a
* trailing \0, 13 characters:
*/
if (size > 12)
{
/* Avoid overflow here on the minimum integer. */
if (fp < 0)
else
{
while (num)
{
/* Split the low digit off num: */
/* Record the first non-zero digit, note that this is a number
* starting at 1, it's not actually the array index.
*/
}
if (ndigits > 0)
{
/* The remaining digits are fractional digits, ndigits is '5' or
* smaller at this point. It is certainly not zero. Check for a
* non-zero fractional digit:
*/
if (first <= 5)
{
unsigned int i;
/* ndigits may be <5 for small numbers, output leading zeros
* then ndigits digits to first:
*/
i = 5;
/* Don't output the trailing zeros! */
}
}
else
*ascii++ = 48;
/* And null terminate the string: */
*ascii = 0;
return;
}
}
/* Here on buffer too small. */
}
# endif /* FIXED_POINT */
#endif /* READ_SCAL */
#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
!defined(PNG_FIXED_POINT_MACRO_SUPPORTED)
{
if (r > 2147483647. || r < -2147483648.)
return (png_fixed_point)r;
}
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) || \
defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG__READ_pHYs_SUPPORTED)
/* muldiv functions */
/* This API takes signed arguments and rounds the result to the nearest
* integer (or, for a fixed point number - the standard argument - to
* the nearest .00001). Overflow and divide by zero are signalled in
* the result, a boolean - true on success, false on overflow.
*/
int
{
/* Return a * times / divisor, rounded. */
if (divisor != 0)
{
if (a == 0 || times == 0)
{
*res = 0;
return 1;
}
else
{
double r = a;
r *= times;
r /= divisor;
r = floor(r+.5);
/* A png_fixed_point is a 32-bit integer. */
if (r <= 2147483647. && r >= -2147483648.)
{
*res = (png_fixed_point)r;
return 1;
}
#else
int negative = 0;
png_uint_32 A, T, D;
if (a < 0)
negative = 1, A = -a;
else
A = a;
if (times < 0)
else
T = times;
if (divisor < 0)
else
D = divisor;
/* Following can't overflow because the arguments only
* have 31 bits each, however the result may be 32 bits.
*/
(A & 0xffff) * (T >> 16);
/* Can't overflow because the a*times bit is only 30
* bits at most.
*/
++s32; /* carry */
if (s32 < D) /* else overflow */
{
/* s32.s00 is now the 64-bit product, do a standard
* division, we know that s32 < D, so the maximum
* required shift is 31.
*/
int bitshift = 32;
while (--bitshift >= 0)
{
if (bitshift > 0)
else
{
}
else
}
/* Handle the rounding. */
if (s00 >= (D >> 1))
++result;
if (negative)
/* Check for overflow. */
{
return 1;
}
}
#endif
}
}
return 0;
}
#endif /* READ_GAMMA || INCH_CONVERSIONS */
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
/* The following is for when the caller doesn't much care about the
* result.
*/
{
return result;
return 0;
}
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED /* more fixed point functions for gammma */
/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
{
if (r <= 2147483647. && r >= -2147483648.)
return (png_fixed_point)r;
#else
return res;
#endif
}
/* A local convenience routine. */
static png_fixed_point
{
/* The required result is 1/a * 1/b; the following preserves accuracy. */
double r = a * 1E-5;
r *= b;
r = floor(r+.5);
if (r <= 2147483647. && r >= -2147483648.)
return (png_fixed_point)r;
#else
return res;
#endif
return 0; /* overflow */
}
/* The inverse of the above. */
{
/* The required result is 1/a * 1/b; the following preserves accuracy. */
double r = 1E15/a;
r /= b;
r = floor(r+.5);
if (r <= 2147483647. && r >= -2147483648.)
return (png_fixed_point)r;
#else
/* This may overflow because the range of png_fixed_point isn't symmetric,
* but this API is only used for the product of file and screen gamma so it
* doesn't matter that the smallest number it can produce is 1/21474, not
* 1/100000
*/
if (res != 0)
return png_reciprocal(res);
#endif
return 0; /* overflow */
}
#endif /* READ_GAMMA */
#ifdef PNG_CHECK_cHRM_SUPPORTED
/* Added at libpng version 1.2.34 (Dec 8, 2008) and 1.4.0 (Jan 2,
* 2010: moved from pngset.c) */
/*
* Multiply two 32-bit numbers, V1 and V2, using 32-bit
*
* 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 /* PRIVATE */
unsigned long *lo_product)
{
int a, b, c, d;
b = v1 & 0xffff;
d = v2 & 0xffff;
lo = b * d; /* BD */
x = a * d + c * b; /* AD + CB */
hi += a * c; /* AC */
*hi_product = (unsigned long)hi;
*lo_product = (unsigned long)lo;
}
#endif /* CHECK_cHRM */
#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
/* Fixed point gamma.
*
* To calculate gamma this code implements fast log() and exp() calls using only
* fixed point arithmetic. This code has sufficient precision for either 8-bit
* or 16-bit sample values.
*
* The tables used here were calculated using simple 'bc' programs, but C double
* precision floating point arithmetic would work fine. The programs are given
* at the head of each table.
*
* 8-bit log table
* This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
* 255, so it's the base 2 logarithm of a normalized 8-bit floating point
* mantissa. The numbers are 32-bit fractions.
*/
static png_uint_32
{
# if PNG_DO_BC
for (i=128;i<256;++i) { .5 - l(i/255)/l(2)*65536*65536; }
# endif
4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
24347096U, 0U
#if 0
/* The following are the values for 16-bit tables - these work fine for the
* 8-bit conversions but produce very slightly larger errors in the 16-bit
* log (about 1.2 as opposed to 0.7 absolute error in the final value). To
* use these all the shifts below must be adjusted appropriately.
*/
65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
1119, 744, 372
#endif
};
png_log8bit(unsigned int x)
{
unsigned int lg2 = 0;
/* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
* because the log is actually negate that means adding 1. The final
* returned value thus has the range 0 (for 255 input) to 7.994 (for 1
* input), return 7.99998 for the overflow (log 0) case - so the result is
* always at most 19 bits.
*/
if ((x &= 0xff) == 0)
return 0xffffffff;
if ((x & 0xf0) == 0)
if ((x & 0xc0) == 0)
if ((x & 0x80) == 0)
/* result is at most 19 bits, so this cast is safe: */
}
/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
* for 16-bit images we use the most significant 8 bits of the 16-bit value to
* get an approximation then multiply the approximation by a correction factor
* determined by the remaining up to 8 bits. This requires an additional step
* in the 16-bit case.
*
* We want log2(value/65535), we have log2(v'/255), where:
*
* value = v' * 256 + v''
* = v' * f
*
* So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
* to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
* than 258. The final factor also needs to correct for the fact that our 8-bit
* value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
*
* This gives a final formula using a calculated value 'x' which is value/v' and
* scaling by 65536 to match the above table:
*
* log2(x/257) * 65536
*
* Since these numbers are so close to '1' we can use simple linear
* interpolation between the two end values 256/257 (result -368.61) and 258/257
* (result 367.179). The values used below are scaled by a further 64 to give
* 16-bit precision in the interpolation:
*
* Start (256): -23591
* Zero (257): 0
* End (258): 23499
*/
{
unsigned int lg2 = 0;
/* As above, but now the input has 16 bits. */
if ((x &= 0xffff) == 0)
return 0xffffffff;
if ((x & 0xff00) == 0)
if ((x & 0xf000) == 0)
if ((x & 0xc000) == 0)
if ((x & 0x8000) == 0)
/* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
* value.
*/
lg2 <<= 28;
/* Now we need to interpolate the factor, this requires a division by the top
* 8 bits. Do this with maximum precision.
*/
x = ((x << 16) + (x >> 9)) / (x >> 8);
/* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
* the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
* 16 bits to interpolate to get the low bits of the result. Round the
* answer. Note that the end point values are scaled by 64 to retain overall
* precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
* the overall scaling by 6-12. Round at every step.
*/
x -= 1U << 24;
if (x <= 65536U) /* <= '257' */
else
/* Safe, because the result can't have more than 20 bits: */
}
/* The 'exp()' case must invert the above, taking a 20-bit fixed point
* logarithmic value and returning a 16 or 8-bit number as appropriate. In
* each case only the low 16 bits are relevant - the fraction - since the
* integer bits (the top 4) simply determine a shift.
*
* The worst case is the 16-bit distinction between 65535 and 65534, this
* requires perhaps spurious accuracty in the decoding of the logarithm to
* distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance
* of getting this accuracy in practice.
*
* To deal with this the following exp() function works out the exponent of the
* frational part of the logarithm by using an accurate 32-bit value from the
* top four fractional bits then multiplying in the remaining bits.
*/
static png_uint_32
{
# if PNG_DO_BC
for (i=0;i<16;++i) { .5 + e(-i/16*l(2))*2^32; }
# endif
/* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
2553802834U, 2445529972U, 2341847524U, 2242560872U
};
/* Adjustment table; provided to explain the numbers in the code below. */
#if PNG_DO_BC
11 44937.64284865548751208448
10 45180.98734845585101160448
9 45303.31936980687359311872
8 45364.65110595323018870784
7 45395.35850361789624614912
6 45410.72259715102037508096
5 45418.40724413220722311168
4 45422.25021786898173001728
3 45424.17186732298419044352
2 45425.13273269940811464704
1 45425.61317555035558641664
0 45425.85339951654943850496
#endif
{
if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
{
/* Obtain a 4-bit approximation */
/* Incorporate the low 12 bits - these decrease the returned value by
* multiplying by a number less than 1 if the bit is set. The multiplier
* is determined by the above table and the shift. Notice that the values
* converge on 45426 and this is used to allow linear interpolation of the
* low bits.
*/
if (x & 0x800)
e -= (((e >> 16) * 44938U) + 16U) >> 5;
if (x & 0x400)
e -= (((e >> 16) * 45181U) + 32U) >> 6;
if (x & 0x200)
e -= (((e >> 16) * 45303U) + 64U) >> 7;
if (x & 0x100)
e -= (((e >> 16) * 45365U) + 128U) >> 8;
if (x & 0x080)
e -= (((e >> 16) * 45395U) + 256U) >> 9;
if (x & 0x040)
e -= (((e >> 16) * 45410U) + 512U) >> 10;
/* And handle the low 6 bits in a single block. */
e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
/* Handle the upper bits of x. */
e >>= x >> 16;
return e;
}
/* Check for overflow */
if (x <= 0)
return png_32bit_exp[0];
/* Else underflow */
return 0;
}
{
/* Get a 32-bit value: */
/* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the
* second, rounding, step can't overflow because of the first, subtraction,
* step.
*/
x -= x >> 8;
}
{
/* Get a 32-bit value: */
/* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
x -= x >> 16;
}
#endif /* FLOATING_ARITHMETIC */
{
{
return (png_byte)r;
# else
return png_exp8bit(res);
/* Overflow. */
value = 0;
# endif
}
}
{
{
return (png_uint_16)r;
# else
return png_exp16bit(res);
/* Overflow. */
value = 0;
# endif
}
return (png_uint_16)value;
}
/* This does the right thing based on the bit_depth field of the
* png_struct, interpreting values as 8-bit or 16-bit. While the result
* is nominally a 16-bit value if bit depth is 8 then the result is
* 8-bit (as are the arguments.)
*/
png_uint_16 /* PRIVATE */
{
else
}
/* This is the shared test on whether a gamma value is 'significant' - whether
* it is worth doing gamma correction.
*/
int /* PRIVATE */
{
}
/* Internal function to build a single 16-bit table - the table consists of
* 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
* to shift the input values right (or 16-number_of_signifiant_bits).
*
* The caller is responsible for ensuring that the table gets cleaned up on
* png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
* should be somewhere that will be cleaned.
*/
static void
{
/* Various values derived from 'shift': */
unsigned int i;
for (i = 0; i < num; i++)
{
/* The 'threshold' test is repeated here because it can arise for one of
* the 16-bit tables even if the others don't hit it.
*/
{
/* The old code would overflow at the end and this would cause the
* 'pow' function to return a result >1, resulting in an
* arithmetic error. This code follows the spec exactly; ig is
* the recovered input sample, it always has 8-16 bits.
*
* We want input * 65535/max, rounded, the arithmetic fits in 32
* bits (unsigned) so long as max <= 32767.
*/
unsigned int j;
for (j = 0; j < 256; j++)
{
/* Inline the 'max' scaling operation: */
sub_table[j] = (png_uint_16)d;
# else
if (shift)
# endif
}
}
else
{
/* We must still build a table, but do it the fast way. */
unsigned int j;
for (j = 0; j < 256; j++)
{
if (shift)
}
}
}
}
/* NOTE: this function expects the *inverse* of the overall gamma transformation
* required.
*/
static void
{
unsigned int i;
/* 'num' is the number of tables and also the number of low bits of low
* bits of the input 16-bit value used to select a table. Each table is
* itself index by the high 8 bits of the value.
*/
for (i = 0; i < num; i++)
/* 'gamma_val' is set to the reciprocal of the value calculated above, so
* pow(out,g) is an *input* value. 'last' is the last input value set.
*
* In the loop 'i' is used to find output values. Since the output is
* 8-bit there are only 256 possible values. The tables are set up to
* select the closest possible output value for each input by finding
* the input value at the boundary between each pair of output values
* and filling the table up to that boundary with the lower output
* value.
*
* The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit
* values the code below uses a 16-bit value in i; the values start at
* 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
* entries are filled with 255). Start i at 128 and fill all 'last'
* table entries <= 'max'
*/
last = 0;
for (i = 0; i < 255; ++i) /* 8-bit output value */
{
/* Find the corresponding maximum input value */
/* Find the boundary value in 16 bits: */
/* Adjust (round) to (16-shift) bits: */
{
last++;
}
}
/* And fill in the final entries. */
{
last++;
}
}
/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
* typically much faster). Note that libpng currently does no sBIT processing
* (apparently contrary to the spec) so a 256 entry table is always generated.
*/
static void
{
unsigned int i;
else for (i=0; i<256; ++i)
}
/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
* tables, we don't make a full table if we are reducing to 8-bit in
* the future. Note also how the gamma_16 tables are segmented so that
* we don't need to allocate > 64K chunks for a full 16-bit table.
*/
void /* PRIVATE */
{
if (bit_depth <= 8)
{
#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
{
}
#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
}
else
{
{
}
else
/* 16-bit gamma code uses this equation:
*
* ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
*
* Where 'iv' is the input color value and 'ov' is the output value -
* pow(iv, gamma).
*
* Thus the gamma table consists of up to 256 256 entry tables. The table
* is selected by the (8-gamma_shift) most significant of the low 8 bits of
* the color value then indexed by the upper 8 bits:
*
* table[low bits][high 8 bits]
*
* So the table 'n' corresponds to all those 'iv' of:
*
* <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
*
*/
else
shift = 0; /* keep all 16 bits */
{
/* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
* the significant bits in the *input* when the output will
* eventually be 8 bits. By default it is 11.
*/
}
if (shift > 8U)
#ifdef PNG_16BIT_SUPPORTED
/* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
* PNG_COMPOSE). This effectively smashed the background calculation for
* 16-bit output because the 8-bit table assumes the result will be reduced
* to 8 bits.
*/
#endif
#ifdef PNG_16BIT_SUPPORTED
else
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
{
/* Notice that the '16 from 1' table should be full precision, however
* the lookup on this table still uses gamma_shift, so it can't be.
* TODO: fix this.
*/
}
#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
}
}
#endif /* READ_GAMMA */
#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */