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[devel] Prefixed variable names index, div, exp, gamma with "png_"

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to avoid "shadow" warnings.  Revised png_fixed() in png.c to avoid compiler
warning about reaching the end without returning anything.
This commit is contained in:
Glenn Randers-Pehrson 2011-01-16 00:38:30 -06:00
parent 5acd8fe9cb
commit e03dd5bd64
3 changed files with 91 additions and 84 deletions
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4
ANNOUNCE
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@ -49,6 +49,10 @@ Version 1.5.1beta04 [January 16, 2011]
macros such as png_memset() are no longer accessible by applications. macros such as png_memset() are no longer accessible by applications.
Corrected pngvalid gamma test "sample" function to access all of the color Corrected pngvalid gamma test "sample" function to access all of the color
samples of each pixel, instead of sampling the red channel three times. samples of each pixel, instead of sampling the red channel three times.
Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
warnings.
Revised png_fixed() in png.c to avoid compiler warning about reaching the
end without returning anything.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net: Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
(subscription required; visit (subscription required; visit

4
CHANGES
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@ -3165,6 +3165,10 @@ Version 1.5.1beta04 [January 16, 2011]
macros such as png_memset() are no longer accessible by applications. macros such as png_memset() are no longer accessible by applications.
Corrected pngvalid gamma test "sample" function to access all of the color Corrected pngvalid gamma test "sample" function to access all of the color
samples of each pixel, instead of sampling the red channel three times. samples of each pixel, instead of sampling the red channel three times.
Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
warnings.
Revised png_fixed() in png.c to avoid compiler warning about reaching the
end without returning anything.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit (subscription required; visit

167
png.c
View File

@ -555,13 +555,13 @@ png_get_copyright(png_structp png_ptr)
#else #else
# ifdef __STDC__ # ifdef __STDC__
return PNG_STRING_NEWLINE \ return PNG_STRING_NEWLINE \
"libpng version 1.5.1beta04 - January 15, 2011" PNG_STRING_NEWLINE \ "libpng version 1.5.1beta04 - January 16, 2011" PNG_STRING_NEWLINE \
"Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \ "Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
"Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
"Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
PNG_STRING_NEWLINE; PNG_STRING_NEWLINE;
# else # else
return "libpng version 1.5.1beta04 - January 15, 2011\ return "libpng version 1.5.1beta04 - January 16, 2011\
Copyright (c) 1998-2011 Glenn Randers-Pehrson\ Copyright (c) 1998-2011 Glenn Randers-Pehrson\
Copyright (c) 1996-1997 Andreas Dilger\ Copyright (c) 1996-1997 Andreas Dilger\
Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."; Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@ -1031,10 +1031,10 @@ int
png_check_fp_string(png_const_charp string, png_size_t size) png_check_fp_string(png_const_charp string, png_size_t size)
{ {
int state=0; int state=0;
png_size_t index=0; png_size_t png_index=0;
return png_check_fp_number(string, size, &state, &index) && return png_check_fp_number(string, size, &state, &png_index) &&
(index == size || string[index] == 0); (png_index == size || string[png_index] == 0);
} }
#endif /* pCAL or sCAL */ #endif /* pCAL or sCAL */
@ -1108,46 +1108,46 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
if (fp >= DBL_MIN && fp <= DBL_MAX) if (fp >= DBL_MIN && fp <= DBL_MAX)
{ {
int exp; /* A base 10 exponent */ int png_exp; /* A base 10 exponent */
double base; /* 10^exp */ double base; /* 10^png_exp */
/* First extract a base 10 exponent of the number, /* First extract a base 10 exponent of the number,
* the calculation below rounds down when converting * the calculation below rounds down when converting
* from base 2 to base 10 (multiply by log10(2) - * from base 2 to base 10 (multiply by log10(2) -
* 0.3010, but 77/256 is 0.3008, so exp needs to * 0.3010, but 77/256 is 0.3008, so png_exp needs to
* be increased. Note that the arithmetic shift * be increased. Note that the arithmetic shift
* performs a floor() unlike C arithmetic - using a * performs a floor() unlike C arithmetic - using a
* C multiply would break the following for negative * C multiply would break the following for negative
* exponents. * exponents.
*/ */
(void)frexp(fp, &exp); /* exponent to base 2 */ (void)frexp(fp, &png_exp); /* exponent to base 2 */
exp = (exp * 77) >> 8; /* <= exponent to base 10 */ png_exp = (png_exp * 77) >> 8; /* <= exponent to base 10 */
/* Avoid underflow here. */ /* Avoid underflow here. */
base = png_pow10(exp); /* May underflow */ base = png_pow10(png_exp); /* May underflow */
while (base < DBL_MIN || base < fp) while (base < DBL_MIN || base < fp)
{ {
/* And this may overflow. */ /* And this may overflow. */
double test = png_pow10(exp+1); double test = png_pow10(png_exp+1);
if (test <= DBL_MAX) if (test <= DBL_MAX)
++exp, base = test; ++png_exp, base = test;
else else
break; break;
} }
/* Normalize fp and correct exp, after this fp is in the /* Normalize fp and correct png_exp, after this fp is in the
* range [.1,1) and exp is both the exponent and the digit * range [.1,1) and png_exp is both the exponent and the digit
* *before* which the decimal point should be inserted * *before* which the decimal point should be inserted
* (starting with 0 for the first digit). Note that this * (starting with 0 for the first digit). Note that this
* works even if 10^exp is out of range because of the * works even if 10^png_exp is out of range because of the
* test on DBL_MAX above. * test on DBL_MAX above.
*/ */
fp /= base; fp /= base;
while (fp >= 1) fp /= 10, ++exp; while (fp >= 1) fp /= 10, ++png_exp;
/* Because of the code above fp may, at this point, be /* Because of the code above fp may, at this point, be
* less than .1, this is ok because the code below can * less than .1, this is ok because the code below can
@ -1162,10 +1162,10 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
/* Allow up to two leading zeros - this will not lengthen /* Allow up to two leading zeros - this will not lengthen
* the number compared to using E-n. * the number compared to using E-n.
*/ */
if (exp < 0 && exp > -3) /* PLUS 3 TOTAL 4 */ if (png_exp < 0 && png_exp > -3) /* PLUS 3 TOTAL 4 */
{ {
czero = -exp; /* PLUS 2 digits: TOTAL 3 */ czero = -png_exp; /* PLUS 2 digits: TOTAL 3 */
exp = 0; /* Dot added below before first output. */ png_exp = 0; /* Dot added below before first output. */
} }
else else
czero = 0; /* No zeros to add */ czero = 0; /* No zeros to add */
@ -1207,17 +1207,17 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
{ {
int ch = *--ascii; int ch = *--ascii;
if (exp != (-1)) if (png_exp != (-1))
++exp; ++png_exp;
else if (ch == 46) else if (ch == 46)
{ {
ch = *--ascii, ++size; ch = *--ascii, ++size;
/* Advance exp to '1', so that the /* Advance png_exp to '1', so that the
* decimal point happens after the * decimal point happens after the
* previous digit. * previous digit.
*/ */
exp = 1; png_exp = 1;
} }
--cdigits; --cdigits;
@ -1230,7 +1230,7 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
*/ */
if (d > 9) /* cdigits == 0 */ if (d > 9) /* cdigits == 0 */
{ {
if (exp == (-1)) if (png_exp == (-1))
{ {
/* Leading decimal point (plus zeros?), if /* Leading decimal point (plus zeros?), if
* we lose the decimal point here it must * we lose the decimal point here it must
@ -1239,14 +1239,14 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
int ch = *--ascii; int ch = *--ascii;
if (ch == 46) if (ch == 46)
++size, exp = 1; ++size, png_exp = 1;
/* Else lost a leading zero, so 'exp' is /* Else lost a leading zero, so 'png_exp' is
* still ok at (-1) * still ok at (-1)
*/ */
} }
else else
++exp; ++png_exp;
/* In all cases we output a '1' */ /* In all cases we output a '1' */
d = 1; d = 1;
@ -1269,23 +1269,23 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
while (czero > 0) while (czero > 0)
{ {
/* exp == (-1) means we just output the decimal /* png_exp == (-1) means we just output the decimal
* place - after the DP don't adjust 'exp' any * place - after the DP don't adjust 'png_exp' any
* more! * more!
*/ */
if (exp != (-1)) if (png_exp != (-1))
{ {
if (exp == 0) *ascii++ = 46, --size; if (png_exp == 0) *ascii++ = 46, --size;
/* PLUS 1: TOTAL 4 */ /* PLUS 1: TOTAL 4 */
--exp; --png_exp;
} }
*ascii++ = 48, --czero; *ascii++ = 48, --czero;
} }
if (exp != (-1)) if (png_exp != (-1))
{ {
if (exp == 0) *ascii++ = 46, --size; /* counted above */ if (png_exp == 0) *ascii++ = 46, --size; /* counted above */
--exp; --png_exp;
} }
*ascii++ = (char)(48 + (int)d), ++cdigits; *ascii++ = (char)(48 + (int)d), ++cdigits;
} }
@ -1296,12 +1296,12 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
/* Check for an exponent, if we don't need one we are /* Check for an exponent, if we don't need one we are
* done and just need to terminate the string. At * done and just need to terminate the string. At
* this point exp==(-1) is effectively if flag - it got * this point png_exp==(-1) is effectively if flag - it got
* to '-1' because of the decrement after outputing * to '-1' because of the decrement after outputing
* the decimal point above (the exponent required is * the decimal point above (the exponent required is
* *not* -1!) * *not* -1!)
*/ */
if (exp >= (-1) && exp <= 2) if (png_exp >= (-1) && png_exp <= 2)
{ {
/* The following only happens if we didn't output the /* The following only happens if we didn't output the
* leading zeros above for negative exponent, so this * leading zeros above for negative exponent, so this
@ -1310,7 +1310,7 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
* zeros were *not* output, so this doesn't increase * zeros were *not* output, so this doesn't increase
* the output count. * the output count.
*/ */
while (--exp >= 0) *ascii++ = 48; while (--png_exp >= 0) *ascii++ = 48;
*ascii = 0; *ascii = 0;
@ -1329,18 +1329,18 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
size -= cdigits; size -= cdigits;
*ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision*/ *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision*/
if (exp < 0) if (png_exp < 0)
{ {
*ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */ *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
exp = -exp; png_exp = -png_exp;
} }
cdigits = 0; cdigits = 0;
while (exp > 0) while (png_exp > 0)
{ {
exponent[cdigits++] = (char)(48 + exp % 10); exponent[cdigits++] = (char)(48 + png_exp % 10);
exp /= 10; png_exp /= 10;
} }
/* Need another size check here for the exponent digits, so /* Need another size check here for the exponent digits, so
@ -1459,11 +1459,10 @@ png_fixed(png_structp png_ptr, double fp, png_const_charp text)
{ {
double r = floor(100000 * fp + .5); double r = floor(100000 * fp + .5);
if (r <= 2147483647. && r >= -2147483648.) if (r > 2147483647. || r < -2147483648.)
return (png_fixed_point)r;
png_fixed_error(png_ptr, text); png_fixed_error(png_ptr, text);
/*NOT REACHED*/
return (png_fixed_point)r;
} }
#endif #endif
@ -1477,10 +1476,10 @@ png_fixed(png_structp png_ptr, double fp, png_const_charp text)
*/ */
int int
png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times, png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
png_int_32 div) png_int_32 png_div)
{ {
/* Return a * times / div, rounded. */ /* Return a * times / png_div, rounded. */
if (div != 0) if (png_div != 0)
{ {
if (a == 0 || times == 0) if (a == 0 || times == 0)
{ {
@ -1492,7 +1491,7 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
double r = a; double r = a;
r *= times; r *= times;
r /= div; r /= png_div;
r = floor(r+.5); r = floor(r+.5);
/* A png_fixed_point is a 32 bit integer. */ /* A png_fixed_point is a 32 bit integer. */
@ -1516,10 +1515,10 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
else else
T = times; T = times;
if (div < 0) if (png_div < 0)
negative = !negative, D = -div; negative = !negative, D = -png_div;
else else
D = div; D = png_div;
/* Following can't overflow because the arguments only /* Following can't overflow because the arguments only
* have 31 bits each, however the result may be 32 bits. * have 31 bits each, however the result may be 32 bits.
@ -1596,11 +1595,11 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
*/ */
png_fixed_point png_fixed_point
png_muldiv_warn(png_structp png_ptr, png_fixed_point a, png_int_32 times, png_muldiv_warn(png_structp png_ptr, png_fixed_point a, png_int_32 times,
png_int_32 div) png_int_32 png_div)
{ {
png_fixed_point result; png_fixed_point result;
if (png_muldiv(&result, a, times, div)) if (png_muldiv(&result, a, times, png_div))
return result; return result;
png_warning(png_ptr, "fixed point overflow ignored"); png_warning(png_ptr, "fixed point overflow ignored");
@ -1987,10 +1986,10 @@ png_exp(png_fixed_point x)
} }
static png_byte static png_byte
png_exp8bit(png_fixed_point log) exp8bit(png_fixed_point log)
{ {
/* Get a 32 bit value: */ /* Get a 32 bit value: */
png_uint_32 x = png_exp(log); png_uint_32 x = exp(log);
/* Convert the 32 bit value to 0..255 by multiplying by 256-1, note that the /* 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, * second, rounding, step can't overflow because of the first, subtraction,
@ -2001,10 +2000,10 @@ png_exp8bit(png_fixed_point log)
} }
static png_uint_16 static png_uint_16
png_exp16bit(png_fixed_point log) exp16bit(png_fixed_point log)
{ {
/* Get a 32 bit value: */ /* Get a 32 bit value: */
png_uint_32 x = png_exp(log); png_uint_32 x = exp(log);
/* Convert the 32 bit value to 0..65535 by multiplying by 65536-1: */ /* Convert the 32 bit value to 0..65535 by multiplying by 65536-1: */
x -= x >> 16; x -= x >> 16;
@ -2013,19 +2012,19 @@ png_exp16bit(png_fixed_point log)
#endif /* FLOATING_ARITHMETIC */ #endif /* FLOATING_ARITHMETIC */
png_byte png_byte
png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma) png_gamma_8bit_correct(unsigned int value, png_fixed_point png_gamma)
{ {
if (value > 0 && value < 255) if (value > 0 && value < 255)
{ {
# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
double r = floor(255*pow(value/255.,gamma*.00001)+.5); double r = floor(255*pow(value/255.,png_gamma*.00001)+.5);
return (png_byte)r; return (png_byte)r;
# else # else
png_int_32 log = png_log8bit(value); png_int_32 log = png_log8bit(value);
png_fixed_point res; png_fixed_point res;
if (png_muldiv(&res, gamma, log, PNG_FP_1)) if (png_muldiv(&res, png_gamma, log, PNG_FP_1))
return png_exp8bit(res); return exp8bit(res);
/* Overflow. */ /* Overflow. */
value = 0; value = 0;
@ -2036,19 +2035,19 @@ png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma)
} }
png_uint_16 png_uint_16
png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma) png_gamma_16bit_correct(unsigned int value, png_fixed_point png_gamma)
{ {
if (value > 0 && value < 65535) if (value > 0 && value < 65535)
{ {
# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
double r = floor(65535*pow(value/65535.,gamma*.00001)+.5); double r = floor(65535*pow(value/65535.,png_gamma*.00001)+.5);
return (png_uint_16)r; return (png_uint_16)r;
# else # else
png_int_32 log = png_log16bit(value); png_int_32 log = png_log16bit(value);
png_fixed_point res; png_fixed_point res;
if (png_muldiv(&res, gamma, log, PNG_FP_1)) if (png_muldiv(&res, png_gamma, log, PNG_FP_1))
return png_exp16bit(res); return exp16bit(res);
/* Overflow. */ /* Overflow. */
value = 0; value = 0;
@ -2065,23 +2064,23 @@ png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma)
*/ */
png_uint_16 /* PRIVATE */ png_uint_16 /* PRIVATE */
png_gamma_correct(png_structp png_ptr, unsigned int value, png_gamma_correct(png_structp png_ptr, unsigned int value,
png_fixed_point gamma) png_fixed_point png_gamma)
{ {
if (png_ptr->bit_depth == 8) if (png_ptr->bit_depth == 8)
return png_gamma_8bit_correct(value, gamma); return png_gamma_8bit_correct(value, png_gamma);
else else
return png_gamma_16bit_correct(value, gamma); return png_gamma_16bit_correct(value, png_gamma);
} }
/* This is the shared test on whether a gamma value is 'significant' - whether /* This is the shared test on whether a gamma value is 'significant' - whether
* it is worth doing gamma correction. * it is worth doing gamma correction.
*/ */
int /* PRIVATE */ int /* PRIVATE */
png_gamma_significant(png_fixed_point gamma) png_gamma_significant(png_fixed_point png_gamma)
{ {
return gamma < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED || return png_gamma < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
gamma > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED; png_gamma > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
} }
/* Internal function to build a single 16 bit table - the table consists of /* Internal function to build a single 16 bit table - the table consists of
@ -2094,7 +2093,7 @@ png_gamma_significant(png_fixed_point gamma)
*/ */
static void static void
png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable, png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable,
PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma) PNG_CONST unsigned int shift, PNG_CONST png_fixed_point png_gamma)
{ {
/* Various values derived from 'shift': */ /* Various values derived from 'shift': */
PNG_CONST unsigned int num = 1U << (8U - shift); PNG_CONST unsigned int num = 1U << (8U - shift);
@ -2113,7 +2112,7 @@ png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable,
/* The 'threshold' test is repeated here because it can arise for one of /* 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 16 bit tables even if the others don't hit it.
*/ */
if (png_gamma_significant(gamma)) if (png_gamma_significant(png_gamma))
{ {
/* The old code would overflow at the end and this would cause the /* The old code would overflow at the end and this would cause the
* 'pow' function to return a result >1, resulting in an * 'pow' function to return a result >1, resulting in an
@ -2129,13 +2128,13 @@ png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable,
png_uint_32 ig = (j << (8-shift)) + i; png_uint_32 ig = (j << (8-shift)) + i;
# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
/* Inline the 'max' scaling operation: */ /* Inline the 'max' scaling operation: */
double d = floor(65535*pow(ig/(double)max, gamma*.00001)+.5); double d = floor(65535*pow(ig/(double)max, png_gamma*.00001)+.5);
sub_table[j] = (png_uint_16)d; sub_table[j] = (png_uint_16)d;
# else # else
if (shift) if (shift)
ig = (ig * 65535U + max_by_2)/max; ig = (ig * 65535U + max_by_2)/max;
sub_table[j] = png_gamma_16bit_correct(ig, gamma); sub_table[j] = png_gamma_16bit_correct(ig, png_gamma);
# endif # endif
} }
} }
@ -2162,7 +2161,7 @@ png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable,
*/ */
static void static void
png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable, png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable,
PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma) PNG_CONST unsigned int shift, PNG_CONST png_fixed_point png_gamma)
{ {
PNG_CONST unsigned int num = 1U << (8U - shift); PNG_CONST unsigned int num = 1U << (8U - shift);
PNG_CONST unsigned int max = (1U << (16U - shift))-1U; PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
@ -2203,7 +2202,7 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable,
png_uint_16 out = (png_uint_16)(i * 257U); /* 16 bit output value */ png_uint_16 out = (png_uint_16)(i * 257U); /* 16 bit output value */
/* Find the boundary value in 16 bits: */ /* Find the boundary value in 16 bits: */
png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma); png_uint_32 bound = png_gamma_16bit_correct(out+128U, png_gamma);
/* Adjust (round) to (16-shift) bits: */ /* Adjust (round) to (16-shift) bits: */
bound = (bound * max + 32768U)/65535U + 1U; bound = (bound * max + 32768U)/65535U + 1U;
@ -2229,13 +2228,13 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable,
*/ */
static void static void
png_build_8bit_table(png_structp png_ptr, png_bytepp ptable, png_build_8bit_table(png_structp png_ptr, png_bytepp ptable,
PNG_CONST png_fixed_point gamma) PNG_CONST png_fixed_point png_gamma)
{ {
unsigned int i; unsigned int i;
png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256); png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
if (png_gamma_significant(gamma)) for (i=0; i<256; i++) if (png_gamma_significant(png_gamma)) for (i=0; i<256; i++)
table[i] = png_gamma_8bit_correct(i, gamma); table[i] = png_gamma_8bit_correct(i, png_gamma);
else for (i=0; i<256; ++i) else for (i=0; i<256; ++i)
table[i] = (png_byte)i; table[i] = (png_byte)i;