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Avoid repeatedly allocating in a loop here
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@aaaaaa123456789
aaaaaa123456789 committed Jan 22, 2022
1 parent a909b00 commit 23e1c82
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Showing 2 changed files with 22 additions and 21 deletions.
40 changes: 20 additions & 20 deletions src/jpegwrite.c
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Original file line number Diff line number Diff line change
Expand Up @@ -91,22 +91,23 @@ void convert_JPEG_components_to_YCbCr (struct context * context, double (* restr
double palette_luminance[256];
double palette_blue[256];
double palette_red[256];
uint64_t * buffer = ctxmalloc(context, sizeof *buffer * ((context -> source -> palette && (context -> source -> max_palette_index > 7)) ?
context -> source -> max_palette_index + 1 : 8));
// define macros to reduce repetition within the function
#define nextunit luminance ++, blue ++, red ++
#define convertblock(rows, cols) do \
if (context -> source -> palette) \
for (row = 0; row < (rows); row ++) for (col = 0; col < (cols); col ++) { \
unsigned char index = data[(unitrow * 8 + row) * context -> source -> width + unitcol * 8 + col], coord = row * 8 + col; \
coord[*luminance] = palette_luminance[index]; \
coord[*blue] = palette_blue[index]; \
coord[*red] = palette_red[index]; \
} \
else { \
size_t index = unitrow * 8 * rowoffset + unitcol * 8 * offset; \
for (row = 0; row < (rows); row ++, index += rowoffset) \
convert_JPEG_colors_to_YCbCr(context, data + index, (cols), context -> source -> color_format, *luminance + 8 * row, \
*blue + 8 * row, *red + 8 * row); \
} \
#define convertblock(rows, cols) do \
if (context -> source -> palette) \
for (row = 0; row < (rows); row ++) for (col = 0; col < (cols); col ++) { \
unsigned char index = data[(unitrow * 8 + row) * context -> source -> width + unitcol * 8 + col], coord = row * 8 + col; \
coord[*luminance] = palette_luminance[index]; \
coord[*blue] = palette_blue[index]; \
coord[*red] = palette_red[index]; \
} \
else { \
size_t index = unitrow * 8 * rowoffset + unitcol * 8 * offset; \
for (row = 0; row < (rows); row ++, index += rowoffset) \
convert_JPEG_colors_to_YCbCr(data + index, cols, context -> source -> color_format, *luminance + 8 * row, *blue + 8 * row, *red + 8 * row, buffer); \
} \
while (0)
#define copyvalues(index, offset) do { \
unsigned char coord = (index); \
Expand All @@ -116,8 +117,8 @@ void convert_JPEG_components_to_YCbCr (struct context * context, double (* restr
} while (0)
// actually do the conversion
if (context -> source -> palette)
convert_JPEG_colors_to_YCbCr(context, context -> source -> palette, context -> source -> max_palette_index + 1, context -> source -> color_format,
palette_luminance, palette_blue, palette_red);
convert_JPEG_colors_to_YCbCr(context -> source -> palette, context -> source -> max_palette_index + 1, context -> source -> color_format, palette_luminance,
palette_blue, palette_red, buffer);
for (unitrow = 0; unitrow < (context -> source -> height >> 3); unitrow ++) {
for (unitcol = 0; unitcol < (context -> source -> width >> 3); unitcol ++) {
convertblock(8, 8);
Expand All @@ -144,11 +145,11 @@ void convert_JPEG_components_to_YCbCr (struct context * context, double (* restr
#undef copyvalues
#undef convertblock
#undef nextunit
ctxfree(context, buffer);
}

void convert_JPEG_colors_to_YCbCr (struct context * context, const void * restrict colors, size_t count, unsigned char flags, double * restrict luminance,
double * restrict blue, double * restrict red) {
uint64_t * buffer = ctxmalloc(context, sizeof *buffer * count);
void convert_JPEG_colors_to_YCbCr (const void * restrict colors, size_t count, unsigned char flags, double * restrict luminance, double * restrict blue,
double * restrict red, uint64_t * restrict buffer) {
plum_convert_colors(buffer, colors, count, PLUM_COLOR_64, flags);
size_t p;
for (p = 0; p < count; p ++) {
Expand All @@ -157,7 +158,6 @@ void convert_JPEG_colors_to_YCbCr (struct context * context, const void * restri
blue[p] = 0.5 * (B - 1.0) - 0x0.2b32468049f7e8p+0 * R - 0x0.54cdb97fb60818p+0 * G;
red[p] = 0.5 * (R - 1.0) - 0x0.6b2f1c1ead19ecp+0 * G - 0x0.14d0e3e152e614p+0 * B;
}
ctxfree(context, buffer);
}

void subsample_JPEG_component (double (* restrict component)[64], double (* restrict output)[64], size_t unitsH, size_t unitsV) {
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3 changes: 2 additions & 1 deletion src/proto.h
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Original file line number Diff line number Diff line change
Expand Up @@ -208,7 +208,8 @@ internal void unpack_JPEG_component(double * restrict, double * restrict, size_t
internal void generate_JPEG_data(struct context *);
internal void calculate_JPEG_quantization_tables(struct context *, uint8_t [restrict static 64], uint8_t [restrict static 64]);
internal void convert_JPEG_components_to_YCbCr(struct context *, double (* restrict)[64], double (* restrict)[64], double (* restrict)[64]);
internal void convert_JPEG_colors_to_YCbCr(struct context *, const void * restrict, size_t, unsigned char, double * restrict, double * restrict, double * restrict);
internal void convert_JPEG_colors_to_YCbCr(const void * restrict, size_t, unsigned char, double * restrict, double * restrict, double * restrict,
uint64_t * restrict);
internal void subsample_JPEG_component(double (* restrict)[64], double (* restrict)[64], size_t, size_t);

// load.c
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