Skip to content

Commit

Permalink
adapt NEON filter optimizations
Browse files Browse the repository at this point in the history
  • Loading branch information
@randy408
randy408 committed May 10, 2021
1 parent 1f653cd commit dacbb7a
Showing 1 changed file with 135 additions and 12 deletions.
147 changes: 135 additions & 12 deletions spng/spng.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,11 @@
static void defilter_avg4(size_t rowbytes, unsigned char *row, const unsigned char *prev);
static void defilter_paeth3(size_t rowbytes, unsigned char *row, const unsigned char *prev);
static void defilter_paeth4(size_t rowbytes, unsigned char *row, const unsigned char *prev);

#if defined(SPNG_ARM)
static uint32_t expand_palette_rgba8_neon(unsigned char *row, const unsigned char *scanline, const unsigned char *plte, uint32_t width);
static uint32_t expand_palette_rgb8_neon(unsigned char *row, const unsigned char *scanline, const unsigned char *plte, uint32_t width);
#endif
#endif
#endif

Expand Down Expand Up @@ -174,6 +179,14 @@ struct spng__iter
const unsigned char *samples;
};

union spng__decode_plte
{
struct spng_plte_entry rgba[256];
unsigned char rgb[256 * 3];
unsigned char raw[256 * 4];
uint32_t align_this;
};

typedef void spng__undo(spng_ctx *ctx);

struct spng_ctx
Expand Down Expand Up @@ -286,7 +299,7 @@ struct spng_ctx
uint16_t *gamma_lut16;
uint16_t gamma_lut8[256];
unsigned char trns_px[8];
struct spng_plte_entry decode_plte[256];
union spng__decode_plte decode_plte;
struct spng_sbit decode_sb;
struct decode_flags decode_flags;
struct spng_row_info row_info;
Expand Down Expand Up @@ -1294,14 +1307,38 @@ static inline void scale_row(unsigned char *row, uint32_t pixels, int fmt, unsig
}

/* Expand to *row using 8-bit palette indices from *scanline */
void expand_row(unsigned char *row, const unsigned char *scanline, const struct spng_plte_entry *plte, uint32_t width, int fmt)
void expand_row(unsigned char *row,
const unsigned char *scanline,
const union spng__decode_plte *decode_plte,
uint32_t width,
int fmt)
{
uint32_t i;
uint32_t i = 0;
unsigned char *px;
unsigned char entry;
const struct spng_plte_entry *plte = decode_plte->rgba;

#if defined(SPNG_ARM)
if(fmt == SPNG_FMT_RGBA8) i = expand_palette_rgba8_neon(row, scanline, decode_plte->raw, width);
else if(fmt == SPNG_FMT_RGB8)
{
i = expand_palette_rgb8_neon(row, scanline, decode_plte->raw, width);

for(; i < width; i++)
{/* In this case the LUT is 3 bytes packed */
px = row + i * 3;
entry = scanline[i];
px[0] = decode_plte->raw[entry * 3 + 0];
px[1] = decode_plte->raw[entry * 3 + 1];
px[2] = decode_plte->raw[entry * 3 + 2];
}
return;
}
#endif

if(fmt == SPNG_FMT_RGBA8)
{
for(i=0; i < width; i++)
for(; i < width; i++)
{
px = row + i * 4;
entry = scanline[i];
Expand All @@ -1313,7 +1350,7 @@ void expand_row(unsigned char *row, const unsigned char *scanline, const struct
}
else if(fmt == SPNG_FMT_RGB8)
{
for(i=0; i < width; i++)
for(; i < width; i++)
{
px = row + i * 3;
entry = scanline[i];
Expand Down Expand Up @@ -2627,7 +2664,7 @@ int spng_decode_scanline(spng_ctx *ctx, void *out, size_t len)
const uint16_t *gamma_lut = ctx->gamma_lut;
unsigned char *trns_px = ctx->trns_px;
const struct spng_sbit *sb = &ctx->decode_sb;
const struct spng_plte_entry *plte = ctx->decode_plte;
const struct spng_plte_entry *plte = ctx->decode_plte.rgba;
struct spng__iter iter = (ihdr->bit_depth < 16) ? spng__iter_init(ihdr->bit_depth, ctx->scanline) : (struct spng__iter){0};

const unsigned char *scanline;
Expand Down Expand Up @@ -2711,7 +2748,7 @@ int spng_decode_scanline(spng_ctx *ctx, void *out, size_t len)
{
if(fmt & (SPNG_FMT_RGBA8 | SPNG_FMT_RGB8))
{
expand_row(out, scanline, plte, width, fmt);
expand_row(out, scanline, &ctx->decode_plte, width, fmt);
break;
}

Expand Down Expand Up @@ -3182,11 +3219,13 @@ int spng_decode_image(spng_ctx *ctx, void *out, size_t len, int fmt, int flags)
sb->alpha_bits == processing_depth &&
processing_depth == depth_target) f.do_scaling = 0;

struct spng_plte_entry *plte = ctx->decode_plte;
struct spng_plte_entry *plte = ctx->decode_plte.rgba;

/* Pre-process palette entries */
if(f.indexed)
{
uint8_t red, green, blue, alpha;

uint32_t i;
for(i=0; i < 256; i++)
{
Expand All @@ -3195,10 +3234,24 @@ int spng_decode_image(spng_ctx *ctx, void *out, size_t len, int fmt, int flags)
else
ctx->plte.entries[i].alpha = 255;

plte[i].red = sample_to_target(ctx->plte.entries[i].red, 8, sb->red_bits, 8);
plte[i].green = sample_to_target(ctx->plte.entries[i].green, 8, sb->green_bits, 8);
plte[i].blue = sample_to_target(ctx->plte.entries[i].blue, 8, sb->blue_bits, 8);
plte[i].alpha = sample_to_target(ctx->plte.entries[i].alpha, 8, sb->alpha_bits, 8);
red = sample_to_target(ctx->plte.entries[i].red, 8, sb->red_bits, 8);
green = sample_to_target(ctx->plte.entries[i].green, 8, sb->green_bits, 8);
blue = sample_to_target(ctx->plte.entries[i].blue, 8, sb->blue_bits, 8);
alpha = sample_to_target(ctx->plte.entries[i].alpha, 8, sb->alpha_bits, 8);

#if defined(SPNG_ARM)
if(fmt == SPNG_FMT_RGB8 && ihdr->bit_depth == 8)
{/* Working with 3 bytes at a time is more of an ARM thing */
ctx->decode_plte.rgb[i * 3 + 0] = red;
ctx->decode_plte.rgb[i * 3 + 1] = green;
ctx->decode_plte.rgb[i * 3 + 2] = blue;
continue;
}
#endif
plte[i].red = red;
plte[i].green = green;
plte[i].blue = blue;
plte[i].alpha = alpha;
}

f.apply_trns = 0;
Expand Down Expand Up @@ -5043,4 +5096,74 @@ static void defilter_paeth4(size_t rowbytes, unsigned char *row, const unsigned
}
}

/* NEON optimised palette expansion functions
* Derived from palette_neon_intrinsics.c
*
* Copyright (c) 2018-2019 Cosmin Truta
* Copyright (c) 2017-2018 Arm Holdings. All rights reserved.
* Written by Richard Townsend <[email protected]>, February 2017.
*
* This code is derived from libpng source code.
* For conditions of distribution and use, see the disclaimer
* and license in this file.
*
* Related: https://developer.arm.com/documentation/101964/latest/Color-palette-expansion
*
* The functions were refactored to iterate forward.
*
*/

/* Expands a palettized row into RGBA8. */
static uint32_t expand_palette_rgba8_neon(unsigned char *row, const unsigned char *scanline, const unsigned char *plte, uint32_t width)
{
const uint32_t stride = 4;
const uint32_t *palette = (const uint32_t*)plte;

if(width < stride) return 0;

uint32_t i;
for(i=0; i < width; i += stride, scanline += stride, row += stride * 4)
{
uint32x4_t cur;
cur = vld1q_dup_u32 (palette + scanline[0]);
cur = vld1q_lane_u32(palette + scanline[1], cur, 1);
cur = vld1q_lane_u32(palette + scanline[2], cur, 2);
cur = vld1q_lane_u32(palette + scanline[3], cur, 3);
vst1q_u32((void*)row, cur);
}

/* Remove the amount that wasn't processed. */
if(i != width) i -= stride;

return i;
}

/* Expands a palettized row into RGB8. */
static uint32_t expand_palette_rgb8_neon(unsigned char *row, const unsigned char *scanline, const unsigned char *plte, uint32_t width)
{
const uint32_t stride = 8;

if(width <= stride) return 0;

uint32_t i;
for(i=0; i < width; i += stride, scanline += stride, row += stride * 3)
{
uint8x8x3_t cur;
cur = vld3_dup_u8 (plte + 3 * scanline[0]);
cur = vld3_lane_u8(plte + 3 * scanline[1], cur, 1);
cur = vld3_lane_u8(plte + 3 * scanline[2], cur, 2);
cur = vld3_lane_u8(plte + 3 * scanline[3], cur, 3);
cur = vld3_lane_u8(plte + 3 * scanline[4], cur, 4);
cur = vld3_lane_u8(plte + 3 * scanline[5], cur, 5);
cur = vld3_lane_u8(plte + 3 * scanline[6], cur, 6);
cur = vld3_lane_u8(plte + 3 * scanline[7], cur, 7);
vst3_u8((void*)row, cur);
}

/* Remove the amount that wasn't processed. */
if(i != width) i -= stride;

return i;
}

#endif /* SPNG_ARM */

0 comments on commit dacbb7a

Please sign in to comment.