diff options
Diffstat (limited to 'plugins/FreeImage/Source/LibPNG/png.c')
| -rw-r--r-- | plugins/FreeImage/Source/LibPNG/png.c | 576 |
1 files changed, 512 insertions, 64 deletions
diff --git a/plugins/FreeImage/Source/LibPNG/png.c b/plugins/FreeImage/Source/LibPNG/png.c index a57175da1d..5a490b2d92 100644 --- a/plugins/FreeImage/Source/LibPNG/png.c +++ b/plugins/FreeImage/Source/LibPNG/png.c @@ -1,7 +1,7 @@ /* png.c - location for general purpose libpng functions
*
- * Last changed in libpng 1.5.4 [July 7, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 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.)
@@ -14,7 +14,7 @@ #include "pngpriv.h"
/* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_5_4 Your_png_h_is_not_version_1_5_4;
+typedef png_libpng_version_1_5_9 Your_png_h_is_not_version_1_5_9;
/* 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
@@ -43,7 +43,7 @@ png_set_sig_bytes(png_structp png_ptr, int num_bytes) * 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).
+ * PNG signature (this is the same behavior as strcmp, memcmp, etc).
*/
int PNGAPI
png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
@@ -107,7 +107,8 @@ png_zfree(voidpf png_ptr, voidpf ptr) void /* PRIVATE */
png_reset_crc(png_structp png_ptr)
{
- png_ptr->crc = crc32(0, Z_NULL, 0);
+ /* The cast is safe because the crc is a 32 bit value. */
+ png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
}
/* Calculate the CRC over a section of data. We can only pass as
@@ -120,21 +121,48 @@ png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length) {
int need_crc = 1;
- if (png_ptr->chunk_name[0] & 0x20) /* ancillary */
+ if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name))
{
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
need_crc = 0;
}
- else /* critical */
+ 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);
+ /* 'uLong' is defined as unsigned long, this means that on some systems it is
+ * a 64 bit value. crc32, however, returns 32 bits so the following cast is
+ * safe. 'uInt' may be no more than 16 bits, so it is necessary to perform a
+ * loop here.
+ */
+ if (need_crc && length > 0)
+ {
+ uLong crc = png_ptr->crc; /* Should never issue a warning */
+
+ do
+ {
+ uInt safeLength = (uInt)length;
+ if (safeLength == 0)
+ safeLength = (uInt)-1; /* evil, but safe */
+
+ crc = crc32(crc, ptr, safeLength);
+
+ /* The following should never issue compiler warnings, if they do the
+ * target system has characteristics that will probably violate other
+ * assumptions within the libpng code.
+ */
+ ptr += safeLength;
+ length -= safeLength;
+ }
+ while (length > 0);
+
+ /* And the following is always safe because the crc is only 32 bits. */
+ png_ptr->crc = (png_uint_32)crc;
+ }
}
/* Check a user supplied version number, called from both read and write
@@ -542,8 +570,8 @@ png_get_io_ptr(png_structp png_ptr) /* 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.
+ * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, 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)
@@ -571,9 +599,19 @@ png_convert_to_rfc1123(png_structp png_ptr, png_const_timep ptime) if (png_ptr == NULL)
return (NULL);
+ if (ptime->year > 9999 /* RFC1123 limitation */ ||
+ ptime->month == 0 || ptime->month > 12 ||
+ ptime->day == 0 || ptime->day > 31 ||
+ ptime->hour > 23 || ptime->minute > 59 ||
+ ptime->second > 60)
+ {
+ png_warning(png_ptr, "Ignoring invalid time value");
+ return (NULL);
+ }
+
{
size_t pos = 0;
- char number_buf[5]; /* enough for a four digit year */
+ char number_buf[5]; /* enough for a four-digit year */
# define APPEND_STRING(string)\
pos = png_safecat(png_ptr->time_buffer, sizeof png_ptr->time_buffer,\
@@ -584,17 +622,17 @@ png_convert_to_rfc1123(png_structp png_ptr, png_const_timep ptime) if (pos < (sizeof png_ptr->time_buffer)-1)\
png_ptr->time_buffer[pos++] = (ch)
- APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day % 32);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
APPEND(' ');
- APPEND_STRING(short_months[(ptime->month - 1) % 12]);
+ APPEND_STRING(short_months[(ptime->month - 1)]);
APPEND(' ');
APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
APPEND(' ');
- APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour % 24);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
APPEND(':');
- APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute % 60);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
APPEND(':');
- APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second % 61);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
# undef APPEND
@@ -617,13 +655,13 @@ png_get_copyright(png_const_structp png_ptr) #else
# ifdef __STDC__
return PNG_STRING_NEWLINE \
- "libpng version 1.5.4 - July 7, 2011" PNG_STRING_NEWLINE \
+ "libpng version 1.5.9 - February 18, 2012" 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." \
PNG_STRING_NEWLINE;
# else
- return "libpng version 1.5.4 - July 7, 2011\
+ return "libpng version 1.5.9 - February 18, 2012\
Copyright (c) 1998-2011 Glenn Randers-Pehrson\
Copyright (c) 1996-1997 Andreas Dilger\
Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -670,25 +708,43 @@ png_get_header_version(png_const_structp png_ptr) #endif
}
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-# ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
int PNGAPI
png_handle_as_unknown(png_structp png_ptr, png_const_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;
+ png_const_bytep p, p_end;
+
+ if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list <= 0)
+ return PNG_HANDLE_CHUNK_AS_DEFAULT;
+
+ p_end = png_ptr->chunk_list;
+ p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
- p = png_ptr->chunk_list + png_ptr->num_chunk_list*5 - 5;
- for (i = png_ptr->num_chunk_list; i; i--, p -= 5)
+ /* The code is the fifth byte after each four byte string. Historically this
+ * code was always searched from the end of the list, so it should continue
+ * to do so in case there are duplicated entries.
+ */
+ do /* num_chunk_list > 0, so at least one */
+ {
+ p -= 5;
if (!png_memcmp(chunk_name, p, 4))
- return ((int)*(p + 4));
- return 0;
+ return p[4];
+ }
+ while (p > p_end);
+
+ return PNG_HANDLE_CHUNK_AS_DEFAULT;
}
-# endif
-#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
+
+int /* PRIVATE */
+png_chunk_unknown_handling(png_structp png_ptr, png_uint_32 chunk_name)
+{
+ png_byte chunk_string[5];
+
+ PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
+ return png_handle_as_unknown(png_ptr, chunk_string);
+}
+#endif
#ifdef PNG_READ_SUPPORTED
/* This function, added to libpng-1.0.6g, is untested. */
@@ -713,18 +769,9 @@ png_access_version_number(void) #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 */
+/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
+ * at libpng 1.5.5!
+ */
/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
# ifdef PNG_CHECK_cHRM_SUPPORTED
@@ -798,6 +845,326 @@ png_check_cHRM_fixed(png_structp png_ptr, }
# endif /* PNG_CHECK_cHRM_SUPPORTED */
+#ifdef PNG_cHRM_SUPPORTED
+/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
+ * cHRM, as opposed to using chromaticities. These internal APIs return
+ * non-zero on a parameter error. The X, Y and Z values are required to be
+ * positive and less than 1.0.
+ */
+int png_xy_from_XYZ(png_xy *xy, png_XYZ XYZ)
+{
+ png_int_32 d, dwhite, whiteX, whiteY;
+
+ d = XYZ.redX + XYZ.redY + XYZ.redZ;
+ if (!png_muldiv(&xy->redx, XYZ.redX, PNG_FP_1, d)) return 1;
+ if (!png_muldiv(&xy->redy, XYZ.redY, PNG_FP_1, d)) return 1;
+ dwhite = d;
+ whiteX = XYZ.redX;
+ whiteY = XYZ.redY;
+
+ d = XYZ.greenX + XYZ.greenY + XYZ.greenZ;
+ if (!png_muldiv(&xy->greenx, XYZ.greenX, PNG_FP_1, d)) return 1;
+ if (!png_muldiv(&xy->greeny, XYZ.greenY, PNG_FP_1, d)) return 1;
+ dwhite += d;
+ whiteX += XYZ.greenX;
+ whiteY += XYZ.greenY;
+
+ d = XYZ.blueX + XYZ.blueY + XYZ.blueZ;
+ if (!png_muldiv(&xy->bluex, XYZ.blueX, PNG_FP_1, d)) return 1;
+ if (!png_muldiv(&xy->bluey, XYZ.blueY, PNG_FP_1, d)) return 1;
+ dwhite += d;
+ whiteX += XYZ.blueX;
+ whiteY += XYZ.blueY;
+
+ /* The reference white is simply the same of the end-point (X,Y,Z) vectors,
+ * thus:
+ */
+ if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1;
+ if (!png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite)) return 1;
+
+ return 0;
+}
+
+int png_XYZ_from_xy(png_XYZ *XYZ, png_xy xy)
+{
+ png_fixed_point red_inverse, green_inverse, blue_scale;
+ png_fixed_point left, right, denominator;
+
+ /* Check xy and, implicitly, z. Note that wide gamut color spaces typically
+ * have end points with 0 tristimulus values (these are impossible end
+ * points, but they are used to cover the possible colors.)
+ */
+ if (xy.redx < 0 || xy.redx > PNG_FP_1) return 1;
+ if (xy.redy < 0 || xy.redy > PNG_FP_1-xy.redx) return 1;
+ if (xy.greenx < 0 || xy.greenx > PNG_FP_1) return 1;
+ if (xy.greeny < 0 || xy.greeny > PNG_FP_1-xy.greenx) return 1;
+ if (xy.bluex < 0 || xy.bluex > PNG_FP_1) return 1;
+ if (xy.bluey < 0 || xy.bluey > PNG_FP_1-xy.bluex) return 1;
+ if (xy.whitex < 0 || xy.whitex > PNG_FP_1) return 1;
+ if (xy.whitey < 0 || xy.whitey > PNG_FP_1-xy.whitex) return 1;
+
+ /* The reverse calculation is more difficult because the original tristimulus
+ * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
+ * derived values were recorded in the cHRM chunk;
+ * (red,green,blue,white)x(x,y). This loses one degree of freedom and
+ * therefore an arbitrary ninth value has to be introduced to undo the
+ * original transformations.
+ *
+ * Think of the original end-points as points in (X,Y,Z) space. The
+ * chromaticity values (c) have the property:
+ *
+ * C
+ * c = ---------
+ * X + Y + Z
+ *
+ * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the
+ * three chromaticity values (x,y,z) for each end-point obey the
+ * relationship:
+ *
+ * x + y + z = 1
+ *
+ * This describes the plane in (X,Y,Z) space that intersects each axis at the
+ * value 1.0; call this the chromaticity plane. Thus the chromaticity
+ * calculation has scaled each end-point so that it is on the x+y+z=1 plane
+ * and chromaticity is the intersection of the vector from the origin to the
+ * (X,Y,Z) value with the chromaticity plane.
+ *
+ * To fully invert the chromaticity calculation we would need the three
+ * end-point scale factors, (red-scale, green-scale, blue-scale), but these
+ * were not recorded. Instead we calculated the reference white (X,Y,Z) and
+ * recorded the chromaticity of this. The reference white (X,Y,Z) would have
+ * given all three of the scale factors since:
+ *
+ * color-C = color-c * color-scale
+ * white-C = red-C + green-C + blue-C
+ * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+ *
+ * But cHRM records only white-x and white-y, so we have lost the white scale
+ * factor:
+ *
+ * white-C = white-c*white-scale
+ *
+ * To handle this the inverse transformation makes an arbitrary assumption
+ * about white-scale:
+ *
+ * Assume: white-Y = 1.0
+ * Hence: white-scale = 1/white-y
+ * Or: red-Y + green-Y + blue-Y = 1.0
+ *
+ * Notice the last statement of the assumption gives an equation in three of
+ * the nine values we want to calculate. 8 more equations come from the
+ * above routine as summarised at the top above (the chromaticity
+ * calculation):
+ *
+ * Given: color-x = color-X / (color-X + color-Y + color-Z)
+ * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
+ *
+ * This is 9 simultaneous equations in the 9 variables "color-C" and can be
+ * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix
+ * determinants, however this is not as bad as it seems because only 28 of
+ * the total of 90 terms in the various matrices are non-zero. Nevertheless
+ * Cramer's rule is notoriously numerically unstable because the determinant
+ * calculation involves the difference of large, but similar, numbers. It is
+ * difficult to be sure that the calculation is stable for real world values
+ * and it is certain that it becomes unstable where the end points are close
+ * together.
+ *
+ * So this code uses the perhaps slighly less optimal but more understandable
+ * and totally obvious approach of calculating color-scale.
+ *
+ * This algorithm depends on the precision in white-scale and that is
+ * (1/white-y), so we can immediately see that as white-y approaches 0 the
+ * accuracy inherent in the cHRM chunk drops off substantially.
+ *
+ * libpng arithmetic: a simple invertion of the above equations
+ * ------------------------------------------------------------
+ *
+ * white_scale = 1/white-y
+ * white-X = white-x * white-scale
+ * white-Y = 1.0
+ * white-Z = (1 - white-x - white-y) * white_scale
+ *
+ * white-C = red-C + green-C + blue-C
+ * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+ *
+ * This gives us three equations in (red-scale,green-scale,blue-scale) where
+ * all the coefficients are now known:
+ *
+ * red-x*red-scale + green-x*green-scale + blue-x*blue-scale
+ * = white-x/white-y
+ * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
+ * red-z*red-scale + green-z*green-scale + blue-z*blue-scale
+ * = (1 - white-x - white-y)/white-y
+ *
+ * In the last equation color-z is (1 - color-x - color-y) so we can add all
+ * three equations together to get an alternative third:
+ *
+ * red-scale + green-scale + blue-scale = 1/white-y = white-scale
+ *
+ * So now we have a Cramer's rule solution where the determinants are just
+ * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve
+ * multiplication of three coefficients so we can't guarantee to avoid
+ * overflow in the libpng fixed point representation. Using Cramer's rule in
+ * floating point is probably a good choice here, but it's not an option for
+ * fixed point. Instead proceed to simplify the first two equations by
+ * eliminating what is likely to be the largest value, blue-scale:
+ *
+ * blue-scale = white-scale - red-scale - green-scale
+ *
+ * Hence:
+ *
+ * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
+ * (white-x - blue-x)*white-scale
+ *
+ * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
+ * 1 - blue-y*white-scale
+ *
+ * And now we can trivially solve for (red-scale,green-scale):
+ *
+ * green-scale =
+ * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
+ * -----------------------------------------------------------
+ * green-x - blue-x
+ *
+ * red-scale =
+ * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale
+ * ---------------------------------------------------------
+ * red-y - blue-y
+ *
+ * Hence:
+ *
+ * red-scale =
+ * ( (green-x - blue-x) * (white-y - blue-y) -
+ * (green-y - blue-y) * (white-x - blue-x) ) / white-y
+ * -------------------------------------------------------------------------
+ * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+ *
+ * green-scale =
+ * ( (red-y - blue-y) * (white-x - blue-x) -
+ * (red-x - blue-x) * (white-y - blue-y) ) / white-y
+ * -------------------------------------------------------------------------
+ * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+ *
+ * Accuracy:
+ * The input values have 5 decimal digits of accuracy. The values are all in
+ * the range 0 < value < 1, so simple products are in the same range but may
+ * need up to 10 decimal digits to preserve the original precision and avoid
+ * underflow. Because we are using a 32-bit signed representation we cannot
+ * match this; the best is a little over 9 decimal digits, less than 10.
+ *
+ * The approach used here is to preserve the maximum precision within the
+ * signed representation. Because the red-scale calculation above uses the
+ * difference between two products of values that must be in the range -1..+1
+ * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The
+ * factor is irrelevant in the calculation because it is applied to both
+ * numerator and denominator.
+ *
+ * Note that the values of the differences of the products of the
+ * chromaticities in the above equations tend to be small, for example for
+ * the sRGB chromaticities they are:
+ *
+ * red numerator: -0.04751
+ * green numerator: -0.08788
+ * denominator: -0.2241 (without white-y multiplication)
+ *
+ * The resultant Y coefficients from the chromaticities of some widely used
+ * color space definitions are (to 15 decimal places):
+ *
+ * sRGB
+ * 0.212639005871510 0.715168678767756 0.072192315360734
+ * Kodak ProPhoto
+ * 0.288071128229293 0.711843217810102 0.000085653960605
+ * Adobe RGB
+ * 0.297344975250536 0.627363566255466 0.075291458493998
+ * Adobe Wide Gamut RGB
+ * 0.258728243040113 0.724682314948566 0.016589442011321
+ */
+ /* By the argument, above overflow should be impossible here. The return
+ * value of 2 indicates an internal error to the caller.
+ */
+ if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.redy - xy.bluey, 7)) return 2;
+ if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.redx - xy.bluex, 7)) return 2;
+ denominator = left - right;
+
+ /* Now find the red numerator. */
+ if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2;
+ if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.whitex-xy.bluex, 7)) return 2;
+
+ /* Overflow is possible here and it indicates an extreme set of PNG cHRM
+ * chunk values. This calculation actually returns the reciprocal of the
+ * scale value because this allows us to delay the multiplication of white-y
+ * into the denominator, which tends to produce a small number.
+ */
+ if (!png_muldiv(&red_inverse, xy.whitey, denominator, left-right) ||
+ red_inverse <= xy.whitey /* r+g+b scales = white scale */)
+ return 1;
+
+ /* Similarly for green_inverse: */
+ if (!png_muldiv(&left, xy.redy-xy.bluey, xy.whitex-xy.bluex, 7)) return 2;
+ if (!png_muldiv(&right, xy.redx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2;
+ if (!png_muldiv(&green_inverse, xy.whitey, denominator, left-right) ||
+ green_inverse <= xy.whitey)
+ return 1;
+
+ /* And the blue scale, the checks above guarantee this can't overflow but it
+ * can still produce 0 for extreme cHRM values.
+ */
+ blue_scale = png_reciprocal(xy.whitey) - png_reciprocal(red_inverse) -
+ png_reciprocal(green_inverse);
+ if (blue_scale <= 0) return 1;
+
+
+ /* And fill in the png_XYZ: */
+ if (!png_muldiv(&XYZ->redX, xy.redx, PNG_FP_1, red_inverse)) return 1;
+ if (!png_muldiv(&XYZ->redY, xy.redy, PNG_FP_1, red_inverse)) return 1;
+ if (!png_muldiv(&XYZ->redZ, PNG_FP_1 - xy.redx - xy.redy, PNG_FP_1,
+ red_inverse))
+ return 1;
+
+ if (!png_muldiv(&XYZ->greenX, xy.greenx, PNG_FP_1, green_inverse)) return 1;
+ if (!png_muldiv(&XYZ->greenY, xy.greeny, PNG_FP_1, green_inverse)) return 1;
+ if (!png_muldiv(&XYZ->greenZ, PNG_FP_1 - xy.greenx - xy.greeny, PNG_FP_1,
+ green_inverse))
+ return 1;
+
+ if (!png_muldiv(&XYZ->blueX, xy.bluex, blue_scale, PNG_FP_1)) return 1;
+ if (!png_muldiv(&XYZ->blueY, xy.bluey, blue_scale, PNG_FP_1)) return 1;
+ if (!png_muldiv(&XYZ->blueZ, PNG_FP_1 - xy.bluex - xy.bluey, blue_scale,
+ PNG_FP_1))
+ return 1;
+
+ return 0; /*success*/
+}
+
+int png_XYZ_from_xy_checked(png_structp png_ptr, png_XYZ *XYZ, png_xy xy)
+{
+ switch (png_XYZ_from_xy(XYZ, xy))
+ {
+ case 0: /* success */
+ return 1;
+
+ case 1:
+ /* The chunk may be technically valid, but we got png_fixed_point
+ * overflow while trying to get XYZ values out of it. This is
+ * entirely benign - the cHRM chunk is pretty extreme.
+ */
+ png_warning(png_ptr,
+ "extreme cHRM chunk cannot be converted to tristimulus values");
+ break;
+
+ default:
+ /* libpng is broken; this should be a warning but if it happens we
+ * want error reports so for the moment it is an error.
+ */
+ png_error(png_ptr, "internal error in png_XYZ_from_xy");
+ break;
+ }
+
+ /* ERROR RETURN */
+ return 0;
+}
+#endif
+
void /* PRIVATE */
png_check_IHDR(png_structp png_ptr,
png_uint_32 width, png_uint_32 height, int bit_depth,
@@ -1383,18 +1750,30 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, size -= cdigits;
*ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */
- if (exp_b10 < 0)
+
+ /* The following use of an unsigned temporary avoids ambiguities in
+ * the signed arithmetic on exp_b10 and permits GCC at least to do
+ * better optimization.
+ */
{
- *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
- exp_b10 = -exp_b10;
- }
+ unsigned int uexp_b10;
- cdigits = 0;
+ if (exp_b10 < 0)
+ {
+ *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
+ uexp_b10 = -exp_b10;
+ }
- while (exp_b10 > 0)
- {
- exponent[cdigits++] = (char)(48 + exp_b10 % 10);
- exp_b10 /= 10;
+ else
+ uexp_b10 = exp_b10;
+
+ cdigits = 0;
+
+ while (uexp_b10 > 0)
+ {
+ exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
+ uexp_b10 /= 10;
+ }
}
/* Need another size check here for the exponent digits, so
@@ -1452,7 +1831,7 @@ png_ascii_from_fixed(png_structp png_ptr, png_charp ascii, png_size_t size, else
num = fp;
- if (num <= 0x80000000U) /* else overflowed */
+ if (num <= 0x80000000) /* else overflowed */
{
unsigned int ndigits = 0, first = 16 /* flag value */;
char digits[10];
@@ -1795,9 +2174,9 @@ png_64bit_product (long v1, long v2, unsigned long *hi_product, static png_uint_32
png_8bit_l2[128] =
{
-# if PNG_DO_BC
+# ifdef PNG_DO_BC
for (i=128;i<256;++i) { .5 - l(i/255)/l(2)*65536*65536; }
-# endif
+# else
4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
@@ -1820,6 +2199,8 @@ png_8bit_l2[128] = 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
24347096U, 0U
+# endif
+
#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
@@ -1954,7 +2335,7 @@ png_log16bit(png_uint_32 x) * 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
+ * requires perhaps spurious accuracy 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.
*
@@ -1965,17 +2346,18 @@ png_log16bit(png_uint_32 x) static png_uint_32
png_32bit_exp[16] =
{
-# if PNG_DO_BC
+# ifdef PNG_DO_BC
for (i=0;i<16;++i) { .5 + e(-i/16*l(2))*2^32; }
-# endif
+# else
/* 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
+# endif
};
/* Adjustment table; provided to explain the numbers in the code below. */
-#if PNG_DO_BC
+#ifdef PNG_DO_BC
for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
11 44937.64284865548751208448
10 45180.98734845585101160448
@@ -2138,7 +2520,7 @@ png_gamma_significant(png_fixed_point gamma_val) }
/* 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
+ * '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
@@ -2225,9 +2607,9 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable, png_uint_16pp table = *ptable =
(png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p));
- /* '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.
+ /* 'num' is the number of tables and also the number of low bits of the
+ * input 16-bit value used to select a table. Each table is itself indexed
+ * by the high 8 bits of the value.
*/
for (i = 0; i < num; i++)
table[i] = (png_uint_16p)png_malloc(png_ptr,
@@ -2278,7 +2660,7 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable, /* 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.
+ * (apparently contrary to the spec) so a 256-entry table is always generated.
*/
static void
png_build_8bit_table(png_structp png_ptr, png_bytepp ptable,
@@ -2294,6 +2676,60 @@ png_build_8bit_table(png_structp png_ptr, png_bytepp ptable, table[i] = (png_byte)i;
}
+/* Used from png_read_destroy and below to release the memory used by the gamma
+ * tables.
+ */
+void /* PRIVATE */
+png_destroy_gamma_table(png_structp png_ptr)
+{
+ png_free(png_ptr, png_ptr->gamma_table);
+ png_ptr->gamma_table = NULL;
+
+ if (png_ptr->gamma_16_table != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_table[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_table);
+ png_ptr->gamma_16_table = NULL;
+ }
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+ png_free(png_ptr, png_ptr->gamma_from_1);
+ png_ptr->gamma_from_1 = NULL;
+ png_free(png_ptr, png_ptr->gamma_to_1);
+ png_ptr->gamma_to_1 = NULL;
+
+ if (png_ptr->gamma_16_from_1 != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_from_1);
+ png_ptr->gamma_16_from_1 = NULL;
+ }
+ if (png_ptr->gamma_16_to_1 != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_to_1);
+ png_ptr->gamma_16_to_1 = NULL;
+ }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+}
+
/* 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
@@ -2304,6 +2740,18 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) {
png_debug(1, "in png_build_gamma_table");
+ /* Remove any existing table; this copes with multiple calls to
+ * png_read_update_info. The warning is because building the gamma tables
+ * multiple times is a performance hit - it's harmless but the ability to call
+ * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible
+ * to warn if the app introduces such a hit.
+ */
+ if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
+ {
+ png_warning(png_ptr, "gamma table being rebuilt");
+ png_destroy_gamma_table(png_ptr);
+ }
+
if (bit_depth <= 8)
{
png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
@@ -2348,7 +2796,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) * 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
+ * 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:
*
|