libpng: Optimize RGBA png_do_expand_palette

third_party/libpng/pngrtran.c

 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
  * Last changed in libpng 1.6.22 [May 26, 2016]
  * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  *
  * This file contains functions optionally called by an application
  * in order to tell libpng how to handle data when reading a PNG.
  * Transformations that are used in both reading and writing are
  * in pngtrans.c.
  */
 
 #include "pngpriv.h"
 
+#ifdef PNG_ARM_NEON_IMPLEMENTATION
+#if PNG_ARM_NEON_IMPLEMENTATION == 1
+#define PNG_ARM_NEON_INTRINSICS_AVAILABLE
+#include <arm_neon.h>
+#endif
+#endif
+
 #ifdef PNG_READ_SUPPORTED
 
 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
 void PNGAPI
 png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
 {
    png_debug(1, "in png_set_crc_action");
 
    if (png_ptr == NULL)
       return;
@@ skipping 4156 matching lines @@
     */
    png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
 }
 #endif
 
 #ifdef PNG_READ_EXPAND_SUPPORTED
 /* Expands a palette row to an RGB or RGBA row depending
  * upon whether you supply trans and num_trans.
  */
 static void
-png_do_expand_palette(png_row_infop row_info, png_bytep row,
-   png_const_colorp palette, png_const_bytep trans_alpha, int num_trans)
+png_do_expand_palette(png_structrp png_ptr, png_row_infop row_info,
+   png_bytep row, png_const_colorp palette, png_const_bytep trans_alpha,
+   int num_trans)
 {
    int shift, value;
    png_bytep sp, dp;
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 
    png_debug(1, "in png_do_expand_palette");
 
    if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
    {
@@ skipping 83 matching lines @@
       }
 
       if (row_info->bit_depth == 8)
       {
          {
             if (num_trans > 0)
             {
                sp = row + (png_size_t)row_width - 1;
                dp = row + (png_size_t)(row_width << 2) - 1;
 
-               for (i = 0; i < row_width; i++)
+               i = 0;
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+               i = png_do_expand_palette_neon(png_ptr, row_info, row, &sp, &dp);
+#endif
+
+               for (; i < row_width; i++)
                {
                   if ((int)(*sp) >= num_trans)
                      *dp-- = 0xff;
-
                   else
                      *dp-- = trans_alpha[*sp];
-
                   *dp-- = palette[*sp].blue;
                   *dp-- = palette[*sp].green;
                   *dp-- = palette[*sp].red;
                   sp--;
                }
                row_info->bit_depth = 8;
                row_info->pixel_depth = 32;
                row_info->rowbytes = row_width * 4;
                row_info->color_type = 6;
                row_info->channels = 4;
@@ skipping 411 matching lines @@
        * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
        */
       png_error(png_ptr, "Uninitialized row");
    }
 
 #ifdef PNG_READ_EXPAND_SUPPORTED
    if ((png_ptr->transformations & PNG_EXPAND) != 0)
    {
       if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
       {
-         png_do_expand_palette(row_info, png_ptr->row_buf + 1,
-             png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+       /* Allocate space for the decompressed full palette. */
+       if (png_ptr->row_tmp_palette == NULL) {
+           png_ptr->row_tmp_palette = png_calloc(png_ptr, 256*4);
+           if (png_ptr->row_tmp_palette == NULL) {
+               png_error(png_ptr, "NULL row buffer");
+           }
+           /* Build the RGBA palette. */
+           png_riffle_palette(png_ptr, row_info);
+       }
+#endif
+         png_do_expand_palette(png_ptr, row_info, png_ptr->row_buf + 1,
+            png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
       }
 
       else
       {
          if (png_ptr->num_trans != 0 &&
              (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
             png_do_expand(row_info, png_ptr->row_buf + 1,
                 &(png_ptr->trans_color));
 
          else
@@ skipping 238 matching lines @@
       row_info->pixel_depth = (png_byte)(row_info->bit_depth *
           row_info->channels);
 
       row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
    }
 #endif
 }
 
 #endif /* READ_TRANSFORMS */
 #endif /* READ */