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LibGfx/JPEG: Use a smaller type to store coefficients

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No need to store them in `i32`, the JPEG norm specifies that they are
not bigger than 16 bits for extended JPEGs. So, in this patch, we
replace `i32` with `i16`. It almost divides memory usage by two :^)
This commit is contained in:
Lucas CHOLLET 2023-03-29 22:25:10 -04:00 • committed by Sam Atkins
parent a744ae79ff
commit cfaa51203f
1 changed files with 18 additions and 18 deletions
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36
Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp
View file

@ -102,21 +102,21 @@ using Marker = u16;
*/ */
struct Macroblock { struct Macroblock {
union { union {
i32 y[64] = { 0 }; i16 y[64] = { 0 };
i32 r[64]; i16 r[64];
}; };
union { union {
i32 cb[64] = { 0 }; i16 cb[64] = { 0 };
i32 g[64]; i16 g[64];
}; };
union { union {
i32 cr[64] = { 0 }; i16 cr[64] = { 0 };
i32 b[64]; i16 b[64];
}; };
i32 k[64] = { 0 }; i16 k[64] = { 0 };
}; };
struct MacroblockMeta { struct MacroblockMeta {
@ -311,7 +311,7 @@ static ErrorOr<u8> get_next_symbol(HuffmanStreamState& hstream, HuffmanTableSpec
return Error::from_string_literal("This kind of JPEG is not yet supported by the decoder"); return Error::from_string_literal("This kind of JPEG is not yet supported by the decoder");
} }
static inline i32* get_component(Macroblock& block, unsigned component) static inline auto* get_component(Macroblock& block, unsigned component)
{ {
switch (component) { switch (component) {
case 0: case 0:
@ -327,7 +327,7 @@ static inline i32* get_component(Macroblock& block, unsigned component)
} }
} }
static ErrorOr<void> refine_coefficient(Scan& scan, i32& coefficient) static ErrorOr<void> refine_coefficient(Scan& scan, auto& coefficient)
{ {
// G.1.2.3 - Coding model for subsequent scans of successive approximation // G.1.2.3 - Coding model for subsequent scans of successive approximation
// See the correction bit from rule b. // See the correction bit from rule b.
@ -1123,7 +1123,7 @@ static void dequantize(JPEGLoadingContext& context, Vector<Macroblock>& macroblo
for (u32 hfactor_i = 0; hfactor_i < component.hsample_factor; hfactor_i++) { for (u32 hfactor_i = 0; hfactor_i < component.hsample_factor; hfactor_i++) {
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor); u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor);
Macroblock& block = macroblocks[macroblock_index]; Macroblock& block = macroblocks[macroblock_index];
int* block_component = get_component(block, i); auto* block_component = get_component(block, i);
for (u32 k = 0; k < 64; k++) for (u32 k = 0; k < 64; k++)
block_component[k] *= table[k]; block_component[k] *= table[k];
} }
@ -1158,7 +1158,7 @@ static void inverse_dct(JPEGLoadingContext const& context, Vector<Macroblock>& m
for (u8 hfactor_i = 0; hfactor_i < component.hsample_factor; hfactor_i++) { for (u8 hfactor_i = 0; hfactor_i < component.hsample_factor; hfactor_i++) {
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor); u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor);
Macroblock& block = macroblocks[macroblock_index]; Macroblock& block = macroblocks[macroblock_index];
i32* block_component = get_component(block, component_i); auto* block_component = get_component(block, component_i);
for (u32 k = 0; k < 8; ++k) { for (u32 k = 0; k < 8; ++k) {
float const g0 = block_component[0 * 8 + k] * s0; float const g0 = block_component[0 * 8 + k] * s0;
float const g1 = block_component[4 * 8 + k] * s4; float const g1 = block_component[4 * 8 + k] * s4;
@ -1333,9 +1333,9 @@ static void ycbcr_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>&
for (u8 vfactor_i = context.vsample_factor - 1; vfactor_i < context.vsample_factor; --vfactor_i) { for (u8 vfactor_i = context.vsample_factor - 1; vfactor_i < context.vsample_factor; --vfactor_i) {
for (u8 hfactor_i = context.hsample_factor - 1; hfactor_i < context.hsample_factor; --hfactor_i) { for (u8 hfactor_i = context.hsample_factor - 1; hfactor_i < context.hsample_factor; --hfactor_i) {
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i); u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
i32* y = macroblocks[macroblock_index].y; auto* y = macroblocks[macroblock_index].y;
i32* cb = macroblocks[macroblock_index].cb; auto* cb = macroblocks[macroblock_index].cb;
i32* cr = macroblocks[macroblock_index].cr; auto* cr = macroblocks[macroblock_index].cr;
for (u8 i = 7; i < 8; --i) { for (u8 i = 7; i < 8; --i) {
for (u8 j = 7; j < 8; --j) { for (u8 j = 7; j < 8; --j) {
const u8 pixel = i * 8 + j; const u8 pixel = i * 8 + j;
@ -1395,10 +1395,10 @@ static void cmyk_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>& m
for (u8 vfactor_i = context.vsample_factor - 1; vfactor_i < context.vsample_factor; --vfactor_i) { for (u8 vfactor_i = context.vsample_factor - 1; vfactor_i < context.vsample_factor; --vfactor_i) {
for (u8 hfactor_i = context.hsample_factor - 1; hfactor_i < context.hsample_factor; --hfactor_i) { for (u8 hfactor_i = context.hsample_factor - 1; hfactor_i < context.hsample_factor; --hfactor_i) {
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i); u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
i32* c = macroblocks[mb_index].y; auto* c = macroblocks[mb_index].y;
i32* m = macroblocks[mb_index].cb; auto* m = macroblocks[mb_index].cb;
i32* y = macroblocks[mb_index].cr; auto* y = macroblocks[mb_index].cr;
i32* k = macroblocks[mb_index].k; auto* k = macroblocks[mb_index].k;
for (u8 i = 0; i < 8; ++i) { for (u8 i = 0; i < 8; ++i) {
for (u8 j = 0; j < 8; ++j) { for (u8 j = 0; j < 8; ++j) {
u8 const pixel = i * 8 + j; u8 const pixel = i * 8 + j;