diff options
| -rw-r--r-- | source/fitz/draw-unpack.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/source/fitz/draw-unpack.c b/source/fitz/draw-unpack.c index 35ee9b41..414e68b7 100644 --- a/source/fitz/draw-unpack.c +++ b/source/fitz/draw-unpack.c @@ -14,6 +14,25 @@ static unsigned char get1_tab_1p[256][16]; static unsigned char get1_tab_255[256][8]; static unsigned char get1_tab_255p[256][16]; +/* + Bug 697012 shows that the unpacking code can confuse valgrind due + to the use of undefined bits in the padding at the end of lines. + We unpack from bits to bytes by copying from a lookup table. + Valgrind is not capable of understanding that it doesn't matter + what the undefined bits are, as the bytes we copy that correspond + to the defined bits will always agree regardless of these + undefined bits by construction of the table. + + We therefore have a VGMASK macro that explicitly masks off these + bits in PACIFY_VALGRIND builds. +*/ +#ifdef PACIFY_VALGRIND +static const unsigned char mask[9] = { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff }; +#define VGMASK(v,m) (v & mask[(m)]) +#else +#define VGMASK(v,m) (v) +#endif + static void init_get1_tables(void) { @@ -92,7 +111,7 @@ fz_unpack_tile(fz_context *ctx, fz_pixmap *dst, unsigned char * restrict src, in } x = x << 3; if (x < w) - memcpy(dp, get1_tab_1[*sp], w - x); + memcpy(dp, get1_tab_1[VGMASK(*sp, w - x)], w - x); } else if (n == 1 && depth == 1 && scale == 255 && !pad && !skip) @@ -105,7 +124,7 @@ fz_unpack_tile(fz_context *ctx, fz_pixmap *dst, unsigned char * restrict src, in } x = x << 3; if (x < w) - memcpy(dp, get1_tab_255[*sp], w - x); + memcpy(dp, get1_tab_255[VGMASK(*sp, w - x)], w - x); } else if (n == 1 && depth == 1 && scale == 1 && pad && !skip) @@ -118,7 +137,7 @@ fz_unpack_tile(fz_context *ctx, fz_pixmap *dst, unsigned char * restrict src, in } x = x << 3; if (x < w) - memcpy(dp, get1_tab_1p[*sp], (w - x) << 1); + memcpy(dp, get1_tab_1p[VGMASK(*sp, w - x)], (w - x) << 1); } else if (n == 1 && depth == 1 && scale == 255 && pad && !skip) @@ -131,7 +150,7 @@ fz_unpack_tile(fz_context *ctx, fz_pixmap *dst, unsigned char * restrict src, in } x = x << 3; if (x < w) - memcpy(dp, get1_tab_255p[*sp], (w - x) << 1); + memcpy(dp, get1_tab_255p[VGMASK(*sp, w - x)], (w - x) << 1); } else if (depth == 8 && !pad && !skip) |