XFA: Upgrade libpng to 1.6.20.

third_party/libpng/pngwtran.c

 
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
- * Last changed in libpng 1.6.0 [February 14, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ * Copyright (c) 1998-2015 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
  */
+
 #include "pngpriv.h"
 
 #ifdef PNG_WRITE_SUPPORTED
-
 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
+ * row_info bit depth should be 8 (one pixel per byte).  The channels
+ * should be 1 (this only happens on grayscale and paletted images).
+ */
+static void
+png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
+{
+   png_debug(1, "in png_do_pack");
+
+   if (row_info->bit_depth == 8 &&
+      row_info->channels == 1)
+   {
+      switch ((int)bit_depth)
+      {
+         case 1:
+         {
+            png_bytep sp, dp;
+            int mask, v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            mask = 0x80;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (*sp != 0)
+                  v |= mask;
+
+               sp++;
+
+               if (mask > 1)
+                  mask >>= 1;
+
+               else
+               {
+                  mask = 0x80;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+            }
+
+            if (mask != 0x80)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp, dp;
+            unsigned int shift;
+            int v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 6;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x03);
+               v |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 6;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+
+               else
+                  shift -= 2;
+
+               sp++;
+            }
+
+            if (shift != 6)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp, dp;
+            unsigned int shift;
+            int v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 4;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x0f);
+               v |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 4;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+
+               else
+                  shift -= 4;
+
+               sp++;
+            }
+
+            if (shift != 4)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         default:
+            break;
+      }
+
+      row_info->bit_depth = (png_byte)bit_depth;
+      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+          row_info->width);
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+/* Shift pixel values to take advantage of whole range.  Pass the
+ * true number of bits in bit_depth.  The row should be packed
+ * according to row_info->bit_depth.  Thus, if you had a row of
+ * bit depth 4, but the pixels only had values from 0 to 7, you
+ * would pass 3 as bit_depth, and this routine would translate the
+ * data to 0 to 15.
+ */
+static void
+png_do_shift(png_row_infop row_info, png_bytep row,
+    png_const_color_8p bit_depth)
+{
+   png_debug(1, "in png_do_shift");
+
+   if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      int shift_start[4], shift_dec[4];
+      int channels = 0;
+
+      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->red;
+         shift_dec[channels] = bit_depth->red;
+         channels++;
+
+         shift_start[channels] = row_info->bit_depth - bit_depth->green;
+         shift_dec[channels] = bit_depth->green;
+         channels++;
+
+         shift_start[channels] = row_info->bit_depth - bit_depth->blue;
+         shift_dec[channels] = bit_depth->blue;
+         channels++;
+      }
+
+      else
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->gray;
+         shift_dec[channels] = bit_depth->gray;
+         channels++;
+      }
+
+      if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
+         shift_dec[channels] = bit_depth->alpha;
+         channels++;
+      }
+
+      /* With low row depths, could only be grayscale, so one channel */
+      if (row_info->bit_depth < 8)
+      {
+         png_bytep bp = row;
+         png_size_t i;
+         unsigned int mask;
+         png_size_t row_bytes = row_info->rowbytes;
+
+         if (bit_depth->gray == 1 && row_info->bit_depth == 2)
+            mask = 0x55;
+
+         else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
+            mask = 0x11;
+
+         else
+            mask = 0xff;
+
+         for (i = 0; i < row_bytes; i++, bp++)
+         {
+            int j;
+            unsigned int v, out;
+
+            v = *bp;
+            out = 0;
+
+            for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
+            {
+               if (j > 0)
+                  out |= v << j;
+
+               else
+                  out |= (v >> (-j)) & mask;
+            }
+
+            *bp = (png_byte)(out & 0xff);
+         }
+      }
+
+      else if (row_info->bit_depth == 8)
+      {
+         png_bytep bp = row;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (i = 0; i < istop; i++, bp++)
+         {
+
+            const unsigned int c = i%channels;
+            int j;
+            unsigned int v, out;
+
+            v = *bp;
+            out = 0;
+
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  out |= v << j;
+
+               else
+                  out |= v >> (-j);
+            }
+
+            *bp = (png_byte)(out & 0xff);
+         }
+      }
+
+      else
+      {
+         png_bytep bp;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (bp = row, i = 0; i < istop; i++)
+         {
+            const unsigned int c = i%channels;
+            int j;
+            unsigned int value, v;
+
+            v = png_get_uint_16(bp);
+            value = 0;
+
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  value |= v << j;
+
+               else
+                  value |= v >> (-j);
+            }
+            *bp++ = (png_byte)((value >> 8) & 0xff);
+            *bp++ = (png_byte)(value & 0xff);
+         }
+      }
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+static void
+png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_swap_alpha");
+
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from ARGB to RGBA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This converts from AARRGGBB to RRGGBBAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from AG to GA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This converts from AAGG to GGAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+static void
+png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_invert_alpha");
+
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This inverts the alpha channel in RGBA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=3; dp = sp;
+               *dp = (png_byte)(255 - *(sp++));
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This inverts the alpha channel in RRGGBBAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=6; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This inverts the alpha channel in GA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This inverts the alpha channel in GGAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=2; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+   }
+}
+#endif
+
 /* Transform the data according to the user's wishes.  The order of
  * transformations is significant.
  */
 void /* PRIVATE */
 png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
 {
    png_debug(1, "in png_do_write_transformations");
 
    if (png_ptr == NULL)
       return;
 
 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
       if (png_ptr->write_user_transform_fn != NULL)
          (*(png_ptr->write_user_transform_fn)) /* User write transform
                                                  function */
              (png_ptr,  /* png_ptr */
              row_info,  /* row_info: */
                 /*  png_uint_32 width;       width of row */
                 /*  png_size_t rowbytes;     number of bytes in row */
                 /*  png_byte color_type;     color type of pixels */
                 /*  png_byte bit_depth;      bit depth of samples */
                 /*  png_byte channels;       number of channels (1-4) */
                 /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
              png_ptr->row_buf + 1);      /* start of pixel data for row */
 #endif
 
 #ifdef PNG_WRITE_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
       png_do_strip_channel(row_info, png_ptr->row_buf + 1,
          !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
 #endif
 
 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
       png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif
 
 #ifdef PNG_WRITE_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
       png_do_pack(row_info, png_ptr->row_buf + 1,
           (png_uint_32)png_ptr->bit_depth);
 #endif
 
 #ifdef PNG_WRITE_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
+#  ifdef PNG_16BIT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
       png_do_swap(row_info, png_ptr->row_buf + 1);
+#  endif
 #endif
 
 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
       png_do_shift(row_info, png_ptr->row_buf + 1,
           &(png_ptr->shift));
 #endif
 
 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
       png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
 #endif
 
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
       png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif
 
 #ifdef PNG_WRITE_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
       png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif
 
 #ifdef PNG_WRITE_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
       png_do_invert(row_info, png_ptr->row_buf + 1);
 #endif
 }
-
-#ifdef PNG_WRITE_PACK_SUPPORTED
-/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
- * row_info bit depth should be 8 (one pixel per byte).  The channels
- * should be 1 (this only happens on grayscale and paletted images).
- */
-void /* PRIVATE */
-png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
-{
-   png_debug(1, "in png_do_pack");
-
-   if (row_info->bit_depth == 8 &&
-      row_info->channels == 1)
-   {
-      switch ((int)bit_depth)
-      {
-         case 1:
-         {
-            png_bytep sp, dp;
-            int mask, v;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            sp = row;
-            dp = row;
-            mask = 0x80;
-            v = 0;
-
-            for (i = 0; i < row_width; i++)
-            {
-               if (*sp != 0)
-                  v |= mask;
-
-               sp++;
-
-               if (mask > 1)
-                  mask >>= 1;
-
-               else
-               {
-                  mask = 0x80;
-                  *dp = (png_byte)v;
-                  dp++;
-                  v = 0;
-               }
-            }
-
-            if (mask != 0x80)
-               *dp = (png_byte)v;
-
-            break;
-         }
-
-         case 2:
-         {
-            png_bytep sp, dp;
-            int shift, v;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            sp = row;
-            dp = row;
-            shift = 6;
-            v = 0;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_byte value;
-
-               value = (png_byte)(*sp & 0x03);
-               v |= (value << shift);
-
-               if (shift == 0)
-               {
-                  shift = 6;
-                  *dp = (png_byte)v;
-                  dp++;
-                  v = 0;
-               }
-
-               else
-                  shift -= 2;
-
-               sp++;
-            }
-
-            if (shift != 6)
-               *dp = (png_byte)v;
-
-            break;
-         }
-
-         case 4:
-         {
-            png_bytep sp, dp;
-            int shift, v;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            sp = row;
-            dp = row;
-            shift = 4;
-            v = 0;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_byte value;
-
-               value = (png_byte)(*sp & 0x0f);
-               v |= (value << shift);
-
-               if (shift == 0)
-               {
-                  shift = 4;
-                  *dp = (png_byte)v;
-                  dp++;
-                  v = 0;
-               }
-
-               else
-                  shift -= 4;
-
-               sp++;
-            }
-
-            if (shift != 4)
-               *dp = (png_byte)v;
-
-            break;
-         }
-
-         default:
-            break;
-      }
-
-      row_info->bit_depth = (png_byte)bit_depth;
-      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
-          row_info->width);
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_SHIFT_SUPPORTED
-/* Shift pixel values to take advantage of whole range.  Pass the
- * true number of bits in bit_depth.  The row should be packed
- * according to row_info->bit_depth.  Thus, if you had a row of
- * bit depth 4, but the pixels only had values from 0 to 7, you
- * would pass 3 as bit_depth, and this routine would translate the
- * data to 0 to 15.
- */
-void /* PRIVATE */
-png_do_shift(png_row_infop row_info, png_bytep row,
-    png_const_color_8p bit_depth)
-{
-   png_debug(1, "in png_do_shift");
-
-   if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
-   {
-      int shift_start[4], shift_dec[4];
-      int channels = 0;
-
-      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
-      {
-         shift_start[channels] = row_info->bit_depth - bit_depth->red;
-         shift_dec[channels] = bit_depth->red;
-         channels++;
-
-         shift_start[channels] = row_info->bit_depth - bit_depth->green;
-         shift_dec[channels] = bit_depth->green;
-         channels++;
-
-         shift_start[channels] = row_info->bit_depth - bit_depth->blue;
-         shift_dec[channels] = bit_depth->blue;
-         channels++;
-      }
-
-      else
-      {
-         shift_start[channels] = row_info->bit_depth - bit_depth->gray;
-         shift_dec[channels] = bit_depth->gray;
-         channels++;
-      }
-
-      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
-      {
-         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
-         shift_dec[channels] = bit_depth->alpha;
-         channels++;
-      }
-
-      /* With low row depths, could only be grayscale, so one channel */
-      if (row_info->bit_depth < 8)
-      {
-         png_bytep bp = row;
-         png_size_t i;
-         unsigned int mask;
-         png_size_t row_bytes = row_info->rowbytes;
-
-         if (bit_depth->gray == 1 && row_info->bit_depth == 2)
-            mask = 0x55;
-
-         else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
-            mask = 0x11;
-
-         else
-            mask = 0xff;
-
-         for (i = 0; i < row_bytes; i++, bp++)
-         {
-            int j;
-            unsigned int v, out;
-
-            v = *bp;
-            out = 0;
-
-            for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
-            {
-               if (j > 0)
-                  out |= v << j;
-
-               else
-                  out |= (v >> (-j)) & mask;
-            }
-
-            *bp = (png_byte)(out & 0xff);
-         }
-      }
-
-      else if (row_info->bit_depth == 8)
-      {
-         png_bytep bp = row;
-         png_uint_32 i;
-         png_uint_32 istop = channels * row_info->width;
-
-         for (i = 0; i < istop; i++, bp++)
-         {
-
-            const unsigned int c = i%channels;
-            int j;
-            unsigned int v, out;
-
-            v = *bp;
-            out = 0;
-
-            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
-            {
-               if (j > 0)
-                  out |= v << j;
-
-               else
-                  out |= v >> (-j);
-            }
-
-            *bp = (png_byte)(out & 0xff);
-         }
-      }
-
-      else
-      {
-         png_bytep bp;
-         png_uint_32 i;
-         png_uint_32 istop = channels * row_info->width;
-
-         for (bp = row, i = 0; i < istop; i++)
-         {
-            const unsigned int c = i%channels;
-            int j;
-            unsigned int value, v;
-
-            v = png_get_uint_16(bp);
-            value = 0;
-
-            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
-            {
-               if (j > 0)
-                  value |= v << j;
-
-               else
-                  value |= v >> (-j);
-            }
-            *bp++ = (png_byte)((value >> 8) & 0xff);
-            *bp++ = (png_byte)(value & 0xff);
-         }
-      }
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-void /* PRIVATE */
-png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_write_swap_alpha");
-
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This converts from ARGB to RGBA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save;
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This converts from AARRGGBB to RRGGBBAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save[2];
-               save[0] = *(sp++);
-               save[1] = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save[0];
-               *(dp++) = save[1];
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This converts from AG to GA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save;
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This converts from AAGG to GGAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save[2];
-               save[0] = *(sp++);
-               save[1] = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save[0];
-               *(dp++) = save[1];
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-void /* PRIVATE */
-png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_write_invert_alpha");
-
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This inverts the alpha channel in RGBA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               /* Does nothing
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               */
-               sp+=3; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This inverts the alpha channel in RRGGBBAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               /* Does nothing
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               */
-               sp+=6; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This inverts the alpha channel in GA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               *(dp++) = *(sp++);
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This inverts the alpha channel in GGAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               /* Does nothing
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               */
-               sp+=2; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-   }
-}
-#endif
-#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-/* Undoes intrapixel differencing  */
-void /* PRIVATE */
-png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_write_intrapixel");
-
-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
-   {
-      int bytes_per_pixel;
-      png_uint_32 row_width = row_info->width;
-      if (row_info->bit_depth == 8)
-      {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 3;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 4;
-
-         else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            *(rp)     = (png_byte)((*rp       - *(rp + 1)) & 0xff);
-            *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
-         }
-      }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-      else if (row_info->bit_depth == 16)
-      {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 6;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 8;
-
-         else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
-            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
-            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
-            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
-            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
-            *(rp    ) = (png_byte)((red >> 8) & 0xff);
-            *(rp + 1) = (png_byte)(red & 0xff);
-            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
-            *(rp + 5) = (png_byte)(blue & 0xff);
-         }
-      }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-   }
-}
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE_TRANSFORMS */
+#endif /* WRITE */