+
+/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
+#if defined(PNG_cHRM_SUPPORTED)
+#if !defined(PNG_NO_CHECK_cHRM)
+/*
+ Multiply two 32-bit numbers, V1 and V2, using 32-bit
+ arithmetic, to produce a 64 bit result in the HI/LO words.
+
+ 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 png_64bit_product (long v1, long v2, unsigned long *hi_product,
+ unsigned long *lo_product)
+{
+ int a, b, c, d;
+ long lo, hi, x, y;
+
+ a = (v1 >> 16) & 0xffff;
+ b = v1 & 0xffff;
+ c = (v2 >> 16) & 0xffff;
+ d = v2 & 0xffff;
+
+ lo = b * d; /* BD */
+ x = a * d + c * b; /* AD + CB */
+ y = ((lo >> 16) & 0xffff) + x;
+
+ lo = (lo & 0xffff) | ((y & 0xffff) << 16);
+ hi = (y >> 16) & 0xffff;
+
+ hi += a * c; /* AC */
+
+ *hi_product = (unsigned long)hi;
+ *lo_product = (unsigned long)lo;
+}
+int /* private */
+png_check_cHRM_fixed(png_structp png_ptr,
+ png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
+ png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
+ png_fixed_point blue_x, png_fixed_point blue_y)
+{
+ int ret = 1;
+ unsigned long xy_hi,xy_lo,yx_hi,yx_lo;
+
+ png_debug(1, "in function png_check_cHRM_fixed");
+ if (png_ptr == NULL)
+ return 0;
+
+ if (white_x < 0 || white_y <= 0 ||
+ red_x < 0 || red_y < 0 ||
+ green_x < 0 || green_y < 0 ||
+ blue_x < 0 || blue_y < 0)
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to set negative chromaticity value");
+ ret = 0;
+ }
+ if (white_x > (png_fixed_point) PNG_UINT_31_MAX ||
+ white_y > (png_fixed_point) PNG_UINT_31_MAX ||
+ red_x > (png_fixed_point) PNG_UINT_31_MAX ||
+ red_y > (png_fixed_point) PNG_UINT_31_MAX ||
+ green_x > (png_fixed_point) PNG_UINT_31_MAX ||
+ green_y > (png_fixed_point) PNG_UINT_31_MAX ||
+ blue_x > (png_fixed_point) PNG_UINT_31_MAX ||
+ blue_y > (png_fixed_point) PNG_UINT_31_MAX )
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to set chromaticity value exceeding 21474.83");
+ ret = 0;
+ }
+ if (white_x > 100000L - white_y)
+ {
+ png_warning(png_ptr, "Invalid cHRM white point");
+ ret = 0;
+ }
+ if (red_x > 100000L - red_y)
+ {
+ png_warning(png_ptr, "Invalid cHRM red point");
+ ret = 0;
+ }
+ if (green_x > 100000L - green_y)
+ {
+ png_warning(png_ptr, "Invalid cHRM green point");
+ ret = 0;
+ }
+ if (blue_x > 100000L - blue_y)
+ {
+ png_warning(png_ptr, "Invalid cHRM blue point");
+ ret = 0;
+ }
+
+ png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo);
+ png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo);
+
+ if (xy_hi == yx_hi && xy_lo == yx_lo)
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to set cHRM RGB triangle with zero area");
+ ret = 0;
+ }
+
+ return ret;
+}
+#endif /* NO_PNG_CHECK_cHRM */
+#endif /* PNG_cHRM_SUPPORTED */
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
projects / wxWidgets.git / blobdiff