remove unused sources

1 files changed, 0 insertions, 1286 deletions

diff --git a/png/pngpread.c b/png/pngpread.c
deleted file mode 100644
index 819db03..0000000
--- a/png/pngpread.c
+++ /dev/null
@@ -1,1286 +0,0 @@
-
-/* pngpread.c - read a png file in push mode
- *
- * Last changed in libpng 1.6.11 [June 12, 2014]
- * Copyright (c) 1998-2014 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_PROGRESSIVE_READ_SUPPORTED
-
-/* Push model modes */
-#define PNG_READ_SIG_MODE   0
-#define PNG_READ_CHUNK_MODE 1
-#define PNG_READ_IDAT_MODE  2
-#define PNG_SKIP_MODE       3
-#define PNG_READ_tEXt_MODE  4
-#define PNG_READ_zTXt_MODE  5
-#define PNG_READ_DONE_MODE  6
-#define PNG_READ_iTXt_MODE  7
-#define PNG_ERROR_MODE      8
-
-void PNGAPI
-png_process_data(png_structrp png_ptr, png_inforp info_ptr,
-    png_bytep buffer, png_size_t buffer_size)
-{
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   png_push_restore_buffer(png_ptr, buffer, buffer_size);
-
-   while (png_ptr->buffer_size)
-   {
-      png_process_some_data(png_ptr, info_ptr);
-   }
-}
-
-png_size_t PNGAPI
-png_process_data_pause(png_structrp png_ptr, int save)
-{
-   if (png_ptr != NULL)
-   {
-      /* It's easiest for the caller if we do the save, then the caller doesn't
-       * have to supply the same data again:
-       */
-      if (save != 0)
-         png_push_save_buffer(png_ptr);
-      else
-      {
-         /* This includes any pending saved bytes: */
-         png_size_t remaining = png_ptr->buffer_size;
-         png_ptr->buffer_size = 0;
-
-         /* So subtract the saved buffer size, unless all the data
-          * is actually 'saved', in which case we just return 0
-          */
-         if (png_ptr->save_buffer_size < remaining)
-            return remaining - png_ptr->save_buffer_size;
-      }
-   }
-
-   return 0;
-}
-
-png_uint_32 PNGAPI
-png_process_data_skip(png_structrp png_ptr)
-{
-   png_uint_32 remaining = 0;
-
-   if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
-      png_ptr->skip_length > 0)
-   {
-      /* At the end of png_process_data the buffer size must be 0 (see the loop
-       * above) so we can detect a broken call here:
-       */
-      if (png_ptr->buffer_size != 0)
-         png_error(png_ptr,
-            "png_process_data_skip called inside png_process_data");
-
-      /* If is impossible for there to be a saved buffer at this point -
-       * otherwise we could not be in SKIP mode.  This will also happen if
-       * png_process_skip is called inside png_process_data (but only very
-       * rarely.)
-       */
-      if (png_ptr->save_buffer_size != 0)
-         png_error(png_ptr, "png_process_data_skip called with saved data");
-
-      remaining = png_ptr->skip_length;
-      png_ptr->skip_length = 0;
-      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-   }
-
-   return remaining;
-}
-
-/* What we do with the incoming data depends on what we were previously
- * doing before we ran out of data...
- */
-void /* PRIVATE */
-png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
-{
-   if (png_ptr == NULL)
-      return;
-
-   switch (png_ptr->process_mode)
-   {
-      case PNG_READ_SIG_MODE:
-      {
-         png_push_read_sig(png_ptr, info_ptr);
-         break;
-      }
-
-      case PNG_READ_CHUNK_MODE:
-      {
-         png_push_read_chunk(png_ptr, info_ptr);
-         break;
-      }
-
-      case PNG_READ_IDAT_MODE:
-      {
-         png_push_read_IDAT(png_ptr);
-         break;
-      }
-
-      case PNG_SKIP_MODE:
-      {
-         png_push_crc_finish(png_ptr);
-         break;
-      }
-
-      default:
-      {
-         png_ptr->buffer_size = 0;
-         break;
-      }
-   }
-}
-
-/* Read any remaining signature bytes from the stream and compare them with
- * the correct PNG signature.  It is possible that this routine is called
- * with bytes already read from the signature, either because they have been
- * checked by the calling application, or because of multiple calls to this
- * routine.
- */
-void /* PRIVATE */
-png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
-{
-   png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */ 
-             num_to_check = 8 - num_checked;
-
-   if (png_ptr->buffer_size < num_to_check)
-   {
-      num_to_check = png_ptr->buffer_size;
-   }
-
-   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
-       num_to_check);
-   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
-
-   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
-   {
-      if (num_checked < 4 &&
-          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
-         png_error(png_ptr, "Not a PNG file");
-
-      else
-         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
-   }
-   else
-   {
-      if (png_ptr->sig_bytes >= 8)
-      {
-         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-      }
-   }
-}
-
-void /* PRIVATE */
-png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
-{
-   png_uint_32 chunk_name;
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-   int keep; /* unknown handling method */
-#endif
-
-   /* First we make sure we have enough data for the 4 byte chunk name
-    * and the 4 byte chunk length before proceeding with decoding the
-    * chunk data.  To fully decode each of these chunks, we also make
-    * sure we have enough data in the buffer for the 4 byte CRC at the
-    * end of every chunk (except IDAT, which is handled separately).
-    */
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
-   {
-      png_byte chunk_length[4];
-      png_byte chunk_tag[4];
-
-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
-      png_reset_crc(png_ptr);
-      png_crc_read(png_ptr, chunk_tag, 4);
-      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
-      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
-      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
-   }
-
-   chunk_name = png_ptr->chunk_name;
-
-   if (chunk_name == png_IDAT)
-   {
-      if (png_ptr->mode & PNG_AFTER_IDAT)
-         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
-
-      /* If we reach an IDAT chunk, this means we have read all of the
-       * header chunks, and we can start reading the image (or if this
-       * is called after the image has been read - we have an error).
-       */
-      if (!(png_ptr->mode & PNG_HAVE_IHDR))
-         png_error(png_ptr, "Missing IHDR before IDAT");
-
-      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-          !(png_ptr->mode & PNG_HAVE_PLTE))
-         png_error(png_ptr, "Missing PLTE before IDAT");
-
-      png_ptr->mode |= PNG_HAVE_IDAT;
-      png_ptr->process_mode = PNG_READ_IDAT_MODE;
-
-      if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-         if (png_ptr->push_length == 0)
-            return;
-
-      if (png_ptr->mode & PNG_AFTER_IDAT)
-         png_benign_error(png_ptr, "Too many IDATs found");
-   }
-
-   if (chunk_name == png_IHDR)
-   {
-      if (png_ptr->push_length != 13)
-         png_error(png_ptr, "Invalid IHDR length");
-
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-   else if (chunk_name == png_IEND)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
-
-      png_ptr->process_mode = PNG_READ_DONE_MODE;
-      png_push_have_end(png_ptr, info_ptr);
-   }
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
-
-      if (chunk_name == png_PLTE)
-         png_ptr->mode |= PNG_HAVE_PLTE;
-   }
-#endif
-
-   else if (chunk_name == png_PLTE)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-   else if (chunk_name == png_IDAT)
-   {
-      png_ptr->idat_size = png_ptr->push_length;
-      png_ptr->process_mode = PNG_READ_IDAT_MODE;
-      png_push_have_info(png_ptr, info_ptr);
-      png_ptr->zstream.avail_out =
-          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
-          png_ptr->iwidth) + 1;
-      png_ptr->zstream.next_out = png_ptr->row_buf;
-      return;
-   }
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-   else if (png_ptr->chunk_name == png_gAMA)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sBIT_SUPPORTED
-   else if (png_ptr->chunk_name == png_sBIT)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_cHRM_SUPPORTED
-   else if (png_ptr->chunk_name == png_cHRM)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sRGB_SUPPORTED
-   else if (chunk_name == png_sRGB)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_iCCP_SUPPORTED
-   else if (png_ptr->chunk_name == png_iCCP)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sPLT_SUPPORTED
-   else if (chunk_name == png_sPLT)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tRNS_SUPPORTED
-   else if (chunk_name == png_tRNS)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_bKGD_SUPPORTED
-   else if (chunk_name == png_bKGD)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_hIST_SUPPORTED
-   else if (chunk_name == png_hIST)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_pHYs_SUPPORTED
-   else if (chunk_name == png_pHYs)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_oFFs_SUPPORTED
-   else if (chunk_name == png_oFFs)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
-   }
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-   else if (chunk_name == png_pCAL)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sCAL_SUPPORTED
-   else if (chunk_name == png_sCAL)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tIME_SUPPORTED
-   else if (chunk_name == png_tIME)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tEXt_SUPPORTED
-   else if (chunk_name == png_tEXt)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_zTXt_SUPPORTED
-   else if (chunk_name == png_zTXt)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_iTXt_SUPPORTED
-   else if (chunk_name == png_iTXt)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-#endif
-
-   else
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
-         PNG_HANDLE_CHUNK_AS_DEFAULT);
-   }
-
-   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-}
-
-void /* PRIVATE */
-png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
-{
-   png_ptr->process_mode = PNG_SKIP_MODE;
-   png_ptr->skip_length = skip;
-}
-
-void /* PRIVATE */
-png_push_crc_finish(png_structrp png_ptr)
-{
-   if (png_ptr->skip_length && png_ptr->save_buffer_size)
-   {
-      png_size_t save_size = png_ptr->save_buffer_size;
-      png_uint_32 skip_length = png_ptr->skip_length;
-
-      /* We want the smaller of 'skip_length' and 'save_buffer_size', but
-       * they are of different types and we don't know which variable has the
-       * fewest bits.  Carefully select the smaller and cast it to the type of
-       * the larger - this cannot overflow.  Do not cast in the following test
-       * - it will break on either 16 or 64 bit platforms.
-       */
-      if (skip_length < save_size)
-         save_size = (png_size_t)skip_length;
-
-      else
-         skip_length = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
-      png_ptr->skip_length -= skip_length;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->save_buffer_size -= save_size;
-      png_ptr->save_buffer_ptr += save_size;
-   }
-   if (png_ptr->skip_length && png_ptr->current_buffer_size)
-   {
-      png_size_t save_size = png_ptr->current_buffer_size;
-      png_uint_32 skip_length = png_ptr->skip_length;
-
-      /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
-       * the same problem exists as above and the same solution.
-       */
-      if (skip_length < save_size)
-         save_size = (png_size_t)skip_length;
-
-      else
-         skip_length = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
-      png_ptr->skip_length -= skip_length;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->current_buffer_size -= save_size;
-      png_ptr->current_buffer_ptr += save_size;
-   }
-   if (!png_ptr->skip_length)
-   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_crc_finish(png_ptr, 0);
-      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-   }
-}
-
-void PNGCBAPI
-png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
-{
-   png_bytep ptr;
-
-   if (png_ptr == NULL)
-      return;
-
-   ptr = buffer;
-   if (png_ptr->save_buffer_size)
-   {
-      png_size_t save_size;
-
-      if (length < png_ptr->save_buffer_size)
-         save_size = length;
-
-      else
-         save_size = png_ptr->save_buffer_size;
-
-      memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
-      length -= save_size;
-      ptr += save_size;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->save_buffer_size -= save_size;
-      png_ptr->save_buffer_ptr += save_size;
-   }
-   if (length && png_ptr->current_buffer_size)
-   {
-      png_size_t save_size;
-
-      if (length < png_ptr->current_buffer_size)
-         save_size = length;
-
-      else
-         save_size = png_ptr->current_buffer_size;
-
-      memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
-      png_ptr->buffer_size -= save_size;
-      png_ptr->current_buffer_size -= save_size;
-      png_ptr->current_buffer_ptr += save_size;
-   }
-}
-
-void /* PRIVATE */
-png_push_save_buffer(png_structrp png_ptr)
-{
-   if (png_ptr->save_buffer_size)
-   {
-      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
-      {
-         png_size_t i, istop;
-         png_bytep sp;
-         png_bytep dp;
-
-         istop = png_ptr->save_buffer_size;
-         for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
-             i < istop; i++, sp++, dp++)
-         {
-            *dp = *sp;
-         }
-      }
-   }
-   if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
-       png_ptr->save_buffer_max)
-   {
-      png_size_t new_max;
-      png_bytep old_buffer;
-
-      if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
-          (png_ptr->current_buffer_size + 256))
-      {
-         png_error(png_ptr, "Potential overflow of save_buffer");
-      }
-
-      new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
-      old_buffer = png_ptr->save_buffer;
-      png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
-          (png_size_t)new_max);
-
-      if (png_ptr->save_buffer == NULL)
-      {
-         png_free(png_ptr, old_buffer);
-         png_error(png_ptr, "Insufficient memory for save_buffer");
-      }
-
-      memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
-      png_free(png_ptr, old_buffer);
-      png_ptr->save_buffer_max = new_max;
-   }
-   if (png_ptr->current_buffer_size)
-   {
-      memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
-         png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
-      png_ptr->save_buffer_size += png_ptr->current_buffer_size;
-      png_ptr->current_buffer_size = 0;
-   }
-   png_ptr->save_buffer_ptr = png_ptr->save_buffer;
-   png_ptr->buffer_size = 0;
-}
-
-void /* PRIVATE */
-png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
-   png_size_t buffer_length)
-{
-   png_ptr->current_buffer = buffer;
-   png_ptr->current_buffer_size = buffer_length;
-   png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
-   png_ptr->current_buffer_ptr = png_ptr->current_buffer;
-}
-
-void /* PRIVATE */
-png_push_read_IDAT(png_structrp png_ptr)
-{
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
-   {
-      png_byte chunk_length[4];
-      png_byte chunk_tag[4];
-
-      /* TODO: this code can be commoned up with the same code in push_read */
-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
-      png_reset_crc(png_ptr);
-      png_crc_read(png_ptr, chunk_tag, 4);
-      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
-      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
-
-      if (png_ptr->chunk_name != png_IDAT)
-      {
-         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-
-         if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
-            png_error(png_ptr, "Not enough compressed data");
-
-         return;
-      }
-
-      png_ptr->idat_size = png_ptr->push_length;
-   }
-
-   if (png_ptr->idat_size && png_ptr->save_buffer_size)
-   {
-      png_size_t save_size = png_ptr->save_buffer_size;
-      png_uint_32 idat_size = png_ptr->idat_size;
-
-      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
-       * are of different types and we don't know which variable has the fewest
-       * bits.  Carefully select the smaller and cast it to the type of the
-       * larger - this cannot overflow.  Do not cast in the following test - it
-       * will break on either 16 or 64 bit platforms.
-       */
-      if (idat_size < save_size)
-         save_size = (png_size_t)idat_size;
-
-      else
-         idat_size = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
-      png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
-      png_ptr->idat_size -= idat_size;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->save_buffer_size -= save_size;
-      png_ptr->save_buffer_ptr += save_size;
-   }
-
-   if (png_ptr->idat_size && png_ptr->current_buffer_size)
-   {
-      png_size_t save_size = png_ptr->current_buffer_size;
-      png_uint_32 idat_size = png_ptr->idat_size;
-
-      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
-       * are of different types and we don't know which variable has the fewest
-       * bits.  Carefully select the smaller and cast it to the type of the
-       * larger - this cannot overflow.
-       */
-      if (idat_size < save_size)
-         save_size = (png_size_t)idat_size;
-
-      else
-         idat_size = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
-      png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
-      png_ptr->idat_size -= idat_size;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->current_buffer_size -= save_size;
-      png_ptr->current_buffer_ptr += save_size;
-   }
-   if (!png_ptr->idat_size)
-   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_crc_finish(png_ptr, 0);
-      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-      png_ptr->mode |= PNG_AFTER_IDAT;
-      png_ptr->zowner = 0;
-   }
-}
-
-void /* PRIVATE */
-png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
-   png_size_t buffer_length)
-{
-   /* The caller checks for a non-zero buffer length. */
-   if (!(buffer_length > 0) || buffer == NULL)
-      png_error(png_ptr, "No IDAT data (internal error)");
-
-   /* This routine must process all the data it has been given
-    * before returning, calling the row callback as required to
-    * handle the uncompressed results.
-    */
-   png_ptr->zstream.next_in = buffer;
-   /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
-   png_ptr->zstream.avail_in = (uInt)buffer_length;
-
-   /* Keep going until the decompressed data is all processed
-    * or the stream marked as finished.
-    */
-   while (png_ptr->zstream.avail_in > 0 &&
-      !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
-   {
-      int ret;
-
-      /* We have data for zlib, but we must check that zlib
-       * has someplace to put the results.  It doesn't matter
-       * if we don't expect any results -- it may be the input
-       * data is just the LZ end code.
-       */
-      if (!(png_ptr->zstream.avail_out > 0))
-      {
-         /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
-         png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
-             png_ptr->iwidth) + 1);
-
-         png_ptr->zstream.next_out = png_ptr->row_buf;
-      }
-
-      /* Using Z_SYNC_FLUSH here means that an unterminated
-       * LZ stream (a stream with a missing end code) can still
-       * be handled, otherwise (Z_NO_FLUSH) a future zlib
-       * implementation might defer output and therefore
-       * change the current behavior (see comments in inflate.c
-       * for why this doesn't happen at present with zlib 1.2.5).
-       */
-      ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
-
-      /* Check for any failure before proceeding. */
-      if (ret != Z_OK && ret != Z_STREAM_END)
-      {
-         /* Terminate the decompression. */
-         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
-         png_ptr->zowner = 0;
-
-         /* This may be a truncated stream (missing or
-          * damaged end code).  Treat that as a warning.
-          */
-         if (png_ptr->row_number >= png_ptr->num_rows ||
-             png_ptr->pass > 6)
-            png_warning(png_ptr, "Truncated compressed data in IDAT");
-
-         else
-            png_error(png_ptr, "Decompression error in IDAT");
-
-         /* Skip the check on unprocessed input */
-         return;
-      }
-
-      /* Did inflate output any data? */
-      if (png_ptr->zstream.next_out != png_ptr->row_buf)
-      {
-         /* Is this unexpected data after the last row?
-          * If it is, artificially terminate the LZ output
-          * here.
-          */
-         if (png_ptr->row_number >= png_ptr->num_rows ||
-             png_ptr->pass > 6)
-         {
-            /* Extra data. */
-            png_warning(png_ptr, "Extra compressed data in IDAT");
-            png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
-            png_ptr->zowner = 0;
-
-            /* Do no more processing; skip the unprocessed
-             * input check below.
-             */
-            return;
-         }
-
-         /* Do we have a complete row? */
-         if (png_ptr->zstream.avail_out == 0)
-            png_push_process_row(png_ptr);
-      }
-
-      /* And check for the end of the stream. */
-      if (ret == Z_STREAM_END)
-         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
-   }
-
-   /* All the data should have been processed, if anything
-    * is left at this point we have bytes of IDAT data
-    * after the zlib end code.
-    */
-   if (png_ptr->zstream.avail_in > 0)
-      png_warning(png_ptr, "Extra compression data in IDAT");
-}
-
-void /* PRIVATE */
-png_push_process_row(png_structrp png_ptr)
-{
-   /* 1.5.6: row_info moved out of png_struct to a local here. */
-   png_row_info row_info;
-
-   row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
-   row_info.color_type = png_ptr->color_type;
-   row_info.bit_depth = png_ptr->bit_depth;
-   row_info.channels = png_ptr->channels;
-   row_info.pixel_depth = png_ptr->pixel_depth;
-   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
-
-   if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
-   {
-      if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
-         png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
-            png_ptr->prev_row + 1, png_ptr->row_buf[0]);
-      else
-         png_error(png_ptr, "bad adaptive filter value");
-   }
-
-   /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
-    * 1.5.6, while the buffer really is this big in current versions of libpng
-    * it may not be in the future, so this was changed just to copy the
-    * interlaced row count:
-    */
-   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   if (png_ptr->transformations)
-      png_do_read_transformations(png_ptr, &row_info);
-#endif
-
-   /* The transformed pixel depth should match the depth now in row_info. */
-   if (png_ptr->transformed_pixel_depth == 0)
-   {
-      png_ptr->transformed_pixel_depth = row_info.pixel_depth;
-      if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
-         png_error(png_ptr, "progressive row overflow");
-   }
-
-   else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
-      png_error(png_ptr, "internal progressive row size calculation error");
-
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Expand interlaced rows to full size */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
-   {
-      if (png_ptr->pass < 6)
-         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
-            png_ptr->transformations);
-
-      switch (png_ptr->pass)
-      {
-         case 0:
-         {
-            int i;
-            for (i = 0; i < 8 && png_ptr->pass == 0; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
-            }
-
-            if (png_ptr->pass == 2) /* Pass 1 might be empty */
-            {
-               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            if (png_ptr->pass == 4 && png_ptr->height <= 4)
-            {
-               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            if (png_ptr->pass == 6 && png_ptr->height <= 4)
-            {
-                png_push_have_row(png_ptr, NULL);
-                png_read_push_finish_row(png_ptr);
-            }
-
-            break;
-         }
-
-         case 1:
-         {
-            int i;
-            for (i = 0; i < 8 && png_ptr->pass == 1; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
-            {
-               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            break;
-         }
-
-         case 2:
-         {
-            int i;
-
-            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 4) /* Pass 3 might be empty */
-            {
-               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            break;
-         }
-
-         case 3:
-         {
-            int i;
-
-            for (i = 0; i < 4 && png_ptr->pass == 3; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 4) /* Skip top two generated rows */
-            {
-               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            break;
-         }
-
-         case 4:
-         {
-            int i;
-
-            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 6) /* Pass 5 might be empty */
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            break;
-         }
-
-         case 5:
-         {
-            int i;
-
-            for (i = 0; i < 2 && png_ptr->pass == 5; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 6) /* Skip top generated row */
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            break;
-         }
-
-         default:
-         case 6:
-         {
-            png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-            png_read_push_finish_row(png_ptr);
-
-            if (png_ptr->pass != 6)
-               break;
-
-            png_push_have_row(png_ptr, NULL);
-            png_read_push_finish_row(png_ptr);
-         }
-      }
-   }
-   else
-   {
-      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-      png_read_push_finish_row(png_ptr);
-   }
-}
-
-void /* PRIVATE */
-png_read_push_finish_row(png_structrp png_ptr)
-{
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
-   /* Start of interlace block */
-   static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* Offset to next interlace block */
-   static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
-
-   /* Start of interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
-
-   /* Offset to next interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
-
-   /* Height of interlace block.  This is not currently used - if you need
-    * it, uncomment it here and in png.h
-   static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
-   */
-#endif
-
-   png_ptr->row_number++;
-   if (png_ptr->row_number < png_ptr->num_rows)
-      return;
-
-   if (png_ptr->interlaced)
-   {
-      png_ptr->row_number = 0;
-      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
-
-      do
-      {
-         png_ptr->pass++;
-         if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
-             (png_ptr->pass == 3 && png_ptr->width < 3) ||
-             (png_ptr->pass == 5 && png_ptr->width < 2))
-            png_ptr->pass++;
-
-         if (png_ptr->pass > 7)
-            png_ptr->pass--;
-
-         if (png_ptr->pass >= 7)
-            break;
-
-         png_ptr->iwidth = (png_ptr->width +
-             png_pass_inc[png_ptr->pass] - 1 -
-             png_pass_start[png_ptr->pass]) /
-             png_pass_inc[png_ptr->pass];
-
-         if (png_ptr->transformations & PNG_INTERLACE)
-            break;
-
-         png_ptr->num_rows = (png_ptr->height +
-             png_pass_yinc[png_ptr->pass] - 1 -
-             png_pass_ystart[png_ptr->pass]) /
-             png_pass_yinc[png_ptr->pass];
-
-      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
-   }
-}
-
-void /* PRIVATE */
-png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
-{
-   if (png_ptr->info_fn != NULL)
-      (*(png_ptr->info_fn))(png_ptr, info_ptr);
-}
-
-void /* PRIVATE */
-png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
-{
-   if (png_ptr->end_fn != NULL)
-      (*(png_ptr->end_fn))(png_ptr, info_ptr);
-}
-
-void /* PRIVATE */
-png_push_have_row(png_structrp png_ptr, png_bytep row)
-{
-   if (png_ptr->row_fn != NULL)
-      (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
-         (int)png_ptr->pass);
-}
-
-void PNGAPI
-png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
-    png_const_bytep new_row)
-{
-   if (png_ptr == NULL)
-      return;
-
-   /* new_row is a flag here - if it is NULL then the app callback was called
-    * from an empty row (see the calls to png_struct::row_fn below), otherwise
-    * it must be png_ptr->row_buf+1
-    */
-   if (new_row != NULL)
-      png_combine_row(png_ptr, old_row, 1/*blocky display*/);
-}
-
-void PNGAPI
-png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
-    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
-    png_progressive_end_ptr end_fn)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->info_fn = info_fn;
-   png_ptr->row_fn = row_fn;
-   png_ptr->end_fn = end_fn;
-
-   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
-}
-
-png_voidp PNGAPI
-png_get_progressive_ptr(png_const_structrp png_ptr)
-{
-   if (png_ptr == NULL)
-      return (NULL);
-
-   return png_ptr->io_ptr;
-}
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */