libpng 1.6.3

third_party/libpng/pngwtran.c

 
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
- * Last changed in libpng 1.2.43 [February 25, 2010]
- * Copyright (c) 1998-2010 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ * Copyright (c) 1998-2013 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
  */
 
-#define PNG_INTERNAL
-#define PNG_NO_PEDANTIC_WARNINGS
-#include "png.h"
+#include "pngpriv.h"
+
 #ifdef PNG_WRITE_SUPPORTED
 
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
 /* Transform the data according to the user's wishes.  The order of
  * transformations is significant.
  */
 void /* PRIVATE */
-png_do_write_transformations(png_structp png_ptr)
+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->write_user_transform_fn != NULL)
-        (*(png_ptr->write_user_transform_fn)) /* User write transform
+         (*(png_ptr->write_user_transform_fn)) /* User write transform
                                                  function */
-          (png_ptr,                    /* png_ptr */
-           &(png_ptr->row_info),       /* row_info:     */
-             /*  png_uint_32 width;          width of row */
-             /*  png_uint_32 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 */
+             (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)
-      png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
-         png_ptr->flags);
+      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)
-      png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+      png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif
+
 #ifdef PNG_WRITE_PACK_SUPPORTED
    if (png_ptr->transformations & PNG_PACK)
-      png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
-         (png_uint_32)png_ptr->bit_depth);
+      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)
-      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+      png_do_swap(row_info, png_ptr->row_buf + 1);
 #endif
+
 #ifdef PNG_WRITE_SHIFT_SUPPORTED
    if (png_ptr->transformations & PNG_SHIFT)
-      png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
-         &(png_ptr->shift));
+      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)
-      png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+      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)
-      png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif
+
 #ifdef PNG_WRITE_BGR_SUPPORTED
    if (png_ptr->transformations & PNG_BGR)
-      png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+      png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif
+
 #ifdef PNG_WRITE_INVERT_SUPPORTED
    if (png_ptr->transformations & PNG_INVERT_MONO)
-      png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
+      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 &&
-#ifdef PNG_USELESS_TESTS_SUPPORTED
-       row != NULL && row_info != NULL &&
-#endif
       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);
+          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_color_8p bit_depth)
+png_do_shift(png_row_infop row_info, png_bytep row,
+    png_const_color_8p bit_depth)
 {
    png_debug(1, "in png_do_shift");
 
-#ifdef PNG_USELESS_TESTS_SUPPORTED
-   if (row != NULL && row_info != NULL &&
-#else
-   if (
-#endif
-      row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   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_uint_32 i;
-         png_byte mask;
-         png_uint_32 row_bytes = row_info->rowbytes;
+         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++)
          {
-            png_uint_16 v;
             int j;
+            unsigned int v, out;
 
             v = *bp;
-            *bp = 0;
+            out = 0;
+
             for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
             {
                if (j > 0)
-                  *bp |= (png_byte)((v << j) & 0xff);
+                  out |= v << j;
+
                else
-                  *bp |= (png_byte)((v >> (-j)) & mask);
+                  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++)
          {
 
-            png_uint_16 v;
+            const unsigned int c = i%channels;
             int j;
-            int c = (int)(i%channels);
+            unsigned int v, out;
 
             v = *bp;
-            *bp = 0;
+            out = 0;
+
             for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
             {
                if (j > 0)
-                  *bp |= (png_byte)((v << j) & 0xff);
+                  out |= v << j;
+
                else
-                  *bp |= (png_byte)((v >> (-j)) & 0xff);
+                  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++)
          {
-            int c = (int)(i%channels);
-            png_uint_16 value, v;
+            const unsigned int c = i%channels;
             int j;
+            unsigned int value, v;
 
-            v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
+            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 |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
+                  value |= v << j;
+
                else
-                  value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
+                  value |= v >> (-j);
             }
-            *bp++ = (png_byte)(value >> 8);
+            *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");
 
-#ifdef PNG_USELESS_TESTS_SUPPORTED
-   if (row != NULL && row_info != NULL)
-#endif
    {
       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
       {
-         /* This converts from ARGB to RGBA */
          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;
             }
          }
-         /* This converts from AARRGGBB to RRGGBBAA */
+
+#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)
       {
-         /* This converts from AG to GA */
          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;
             }
          }
-         /* This converts from AAGG to GGAA */
+
+#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");
 
-#ifdef PNG_USELESS_TESTS_SUPPORTED
-   if (row != NULL && row_info != NULL)
-#endif
    {
       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
       {
-         /* This inverts the alpha channel in RGBA */
          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++));
             }
          }
-         /* This inverts the alpha channel in RRGGBBAA */
+
+#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)
       {
-         /* This inverts the alpha channel in GA */
          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++));
             }
          }
-         /* This inverts the alpha channel in GGAA */
+
+#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 (
-#ifdef PNG_USELESS_TESTS_SUPPORTED
-       row != NULL && row_info != NULL &&
-#endif
-       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   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);
+            *(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 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);
+            *(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 */