pngpread.c

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
   length)
{
   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
      {
         png_error(png_ptr, "Out of place tEXt");
         /* to quiet some compiler warnings */
         if(info_ptr == NULL) return;
      }

#ifdef PNG_MAX_MALLOC_64K
   png_ptr->skip_length = 0;  /* This may not be necessary */

   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
   {
      png_warning(png_ptr, "tEXt chunk too large to fit in memory");
      png_ptr->skip_length = length - (png_uint_32)65535L;
      length = (png_uint_32)65535L;
   }
#endif

   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
         (png_uint_32)(length+1));
   png_ptr->current_text[length] = '\0';
   png_ptr->current_text_ptr = png_ptr->current_text;
   png_ptr->current_text_size = (png_size_t)length;
   png_ptr->current_text_left = (png_size_t)length;
   png_ptr->process_mode = PNG_READ_tEXt_MODE;
}

void /* PRIVATE */
png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr->buffer_size && png_ptr->current_text_left)
   {
      png_size_t text_size;

      if (png_ptr->buffer_size < png_ptr->current_text_left)
         text_size = png_ptr->buffer_size;
      else
         text_size = png_ptr->current_text_left;
      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
      png_ptr->current_text_left -= text_size;
      png_ptr->current_text_ptr += text_size;
   }
   if (!(png_ptr->current_text_left))
   {
      png_textp text_ptr;
      png_charp text;
      png_charp key;
      int ret;

      if (png_ptr->buffer_size < 4)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_push_crc_finish(png_ptr);

#if defined(PNG_MAX_MALLOC_64K)
      if (png_ptr->skip_length)
         return;
#endif

      key = png_ptr->current_text;

      for (text = key; *text; text++)
         /* empty loop */ ;

      if (text != key + png_ptr->current_text_size)
         text++;

      text_ptr = (png_textp)png_malloc(png_ptr,
         (png_uint_32)png_sizeof(png_text));
      text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
      text_ptr->key = key;
#ifdef PNG_iTXt_SUPPORTED
      text_ptr->lang = NULL;
      text_ptr->lang_key = NULL;
#endif
      text_ptr->text = text;

      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);

      png_free(png_ptr, key);
      png_free(png_ptr, text_ptr);
      png_ptr->current_text = NULL;

      if (ret)
        png_warning(png_ptr, "Insufficient memory to store text chunk.");
   }
}
#endif

#if defined(PNG_READ_zTXt_SUPPORTED)
void /* PRIVATE */
png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
   length)
{
   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
      {
         png_error(png_ptr, "Out of place zTXt");
         /* to quiet some compiler warnings */
         if(info_ptr == NULL) return;
      }

#ifdef PNG_MAX_MALLOC_64K
   /* We can't handle zTXt chunks > 64K, since we don't have enough space
    * to be able to store the uncompressed data.  Actually, the threshold
    * is probably around 32K, but it isn't as definite as 64K is.
    */
   if (length > (png_uint_32)65535L)
   {
      png_warning(png_ptr, "zTXt chunk too large to fit in memory");
      png_push_crc_skip(png_ptr, length);
      return;
   }
#endif

   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
       (png_uint_32)(length+1));
   png_ptr->current_text[length] = '\0';
   png_ptr->current_text_ptr = png_ptr->current_text;
   png_ptr->current_text_size = (png_size_t)length;
   png_ptr->current_text_left = (png_size_t)length;
   png_ptr->process_mode = PNG_READ_zTXt_MODE;
}

void /* PRIVATE */
png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr->buffer_size && png_ptr->current_text_left)
   {
      png_size_t text_size;

      if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
         text_size = png_ptr->buffer_size;
      else
         text_size = png_ptr->current_text_left;
      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
      png_ptr->current_text_left -= text_size;
      png_ptr->current_text_ptr += text_size;
   }
   if (!(png_ptr->current_text_left))
   {
      png_textp text_ptr;
      png_charp text;
      png_charp key;
      int ret;
      png_size_t text_size, key_size;

      if (png_ptr->buffer_size < 4)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_push_crc_finish(png_ptr);

      key = png_ptr->current_text;

      for (text = key; *text; text++)
         /* empty loop */ ;

      /* zTXt can't have zero text */
      if (text == key + png_ptr->current_text_size)
      {
         png_ptr->current_text = NULL;
         png_free(png_ptr, key);
         return;
      }

      text++;

      if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
      {
         png_ptr->current_text = NULL;
         png_free(png_ptr, key);
         return;
      }

      text++;

      png_ptr->zstream.next_in = (png_bytep )text;
      png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
         (text - key));
      png_ptr->zstream.next_out = png_ptr->zbuf;
      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

      key_size = text - key;
      text_size = 0;
      text = NULL;
      ret = Z_STREAM_END;

      while (png_ptr->zstream.avail_in)
      {
         ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
         if (ret != Z_OK && ret != Z_STREAM_END)
         {
            inflateReset(&png_ptr->zstream);
            png_ptr->zstream.avail_in = 0;
            png_ptr->current_text = NULL;
            png_free(png_ptr, key);
            png_free(png_ptr, text);
            return;
         }
         if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
         {
            if (text == NULL)
            {
               text = (png_charp)png_malloc(png_ptr,
                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
                     + key_size + 1));
               png_memcpy(text + key_size, png_ptr->zbuf,
                  png_ptr->zbuf_size - png_ptr->zstream.avail_out);
               png_memcpy(text, key, key_size);
               text_size = key_size + png_ptr->zbuf_size -
                  png_ptr->zstream.avail_out;
               *(text + text_size) = '\0';
            }
            else
            {
               png_charp tmp;

               tmp = text;
               text = (png_charp)png_malloc(png_ptr, text_size +
                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
                   + 1));
               png_memcpy(text, tmp, text_size);
               png_free(png_ptr, tmp);
               png_memcpy(text + text_size, png_ptr->zbuf,
                  png_ptr->zbuf_size - png_ptr->zstream.avail_out);
               text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
               *(text + text_size) = '\0';
            }
            if (ret != Z_STREAM_END)
            {
               png_ptr->zstream.next_out = png_ptr->zbuf;
               png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
            }
         }
         else
         {
            break;
         }

         if (ret == Z_STREAM_END)
            break;
      }

      inflateReset(&png_ptr->zstream);
      png_ptr->zstream.avail_in = 0;

      if (ret != Z_STREAM_END)
      {
         png_ptr->current_text = NULL;
         png_free(png_ptr, key);
         png_free(png_ptr, text);
         return;
      }

      png_ptr->current_text = NULL;
      png_free(png_ptr, key);
      key = text;
      text += key_size;

      text_ptr = (png_textp)png_malloc(png_ptr,
          (png_uint_32)png_sizeof(png_text));
      text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
      text_ptr->key = key;
#ifdef PNG_iTXt_SUPPORTED
      text_ptr->lang = NULL;
      text_ptr->lang_key = NULL;
#endif
      text_ptr->text = text;

      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);

      png_free(png_ptr, key);
      png_free(png_ptr, text_ptr);

      if (ret)
        png_warning(png_ptr, "Insufficient memory to store text chunk.");
   }
}
#endif

#if defined(PNG_READ_iTXt_SUPPORTED)
void /* PRIVATE */
png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
   length)
{
   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
      {
         png_error(png_ptr, "Out of place iTXt");
         /* to quiet some compiler warnings */
         if(info_ptr == NULL) return;
      }

#ifdef PNG_MAX_MALLOC_64K
   png_ptr->skip_length = 0;  /* This may not be necessary */

   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
   {
      png_warning(png_ptr, "iTXt chunk too large to fit in memory");
      png_ptr->skip_length = length - (png_uint_32)65535L;
      length = (png_uint_32)65535L;
   }
#endif

   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
         (png_uint_32)(length+1));
   png_ptr->current_text[length] = '\0';
   png_ptr->current_text_ptr = png_ptr->current_text;
   png_ptr->current_text_size = (png_size_t)length;
   png_ptr->current_text_left = (png_size_t)length;
   png_ptr->process_mode = PNG_READ_iTXt_MODE;
}

void /* PRIVATE */
png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
{

   if (png_ptr->buffer_size && png_ptr->current_text_left)
   {
      png_size_t text_size;

      if (png_ptr->buffer_size < png_ptr->current_text_left)
         text_size = png_ptr->buffer_size;
      else
         text_size = png_ptr->current_text_left;
      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
      png_ptr->current_text_left -= text_size;
      png_ptr->current_text_ptr += text_size;
   }
   if (!(png_ptr->current_text_left))
   {
      png_textp text_ptr;
      png_charp key;
      int comp_flag;
      png_charp lang;
      png_charp lang_key;
      png_charp text;
      int ret;

      if (png_ptr->buffer_size < 4)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_push_crc_finish(png_ptr);

#if defined(PNG_MAX_MALLOC_64K)
      if (png_ptr->skip_length)
         return;
#endif

      key = png_ptr->current_text;

      for (lang = key; *lang; lang++)
         /* empty loop */ ;

      if (lang != key + png_ptr->current_text_size)
         lang++;

      comp_flag = *lang++;
      lang++;     /* skip comp_type, always zero */

      for (lang_key = lang; *lang_key; lang_key++)
         /* empty loop */ ;
      lang_key++;        /* skip NUL separator */

      for (text = lang_key; *text; text++)
         /* empty loop */ ;

      if (text != key + png_ptr->current_text_size)
         text++;

      text_ptr = (png_textp)png_malloc(png_ptr,
         (png_uint_32)png_sizeof(png_text));
      text_ptr->compression = comp_flag + 2;
      text_ptr->key = key;
      text_ptr->lang = lang;
      text_ptr->lang_key = lang_key;
      text_ptr->text = text;
      text_ptr->text_length = 0;
      text_ptr->itxt_length = png_strlen(text);

      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);

      png_ptr->current_text = NULL;

      png_free(png_ptr, text_ptr);
      if (ret)
        png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
   }
}
#endif

/* This function is called when we haven't found a handler for this
 * chunk.  If there isn't a problem with the chunk itself (ie a bad chunk
 * name or a critical chunk), the chunk is (currently) silently ignored.
 */
void /* PRIVATE */
png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
   length)
{
   png_uint_32 skip=0;
   png_check_chunk_name(png_ptr, png_ptr->chunk_name);

   if (!(png_ptr->chunk_name[0] & 0x20))
   {
#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
      if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
           PNG_HANDLE_CHUNK_ALWAYS
#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
           && png_ptr->read_user_chunk_fn == NULL
#endif
         )
#endif
         png_chunk_error(png_ptr, "unknown critical chunk");

      /* to quiet compiler warnings about unused info_ptr */
      if (info_ptr == NULL)
         return;
   }

#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
   if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
   {
       png_unknown_chunk chunk;

#ifdef PNG_MAX_MALLOC_64K
       if (length > (png_uint_32)65535L)
       {
           png_warning(png_ptr, "unknown chunk too large to fit in memory");
           skip = length - (png_uint_32)65535L;
           length = (png_uint_32)65535L;
       }
#endif

       png_strcpy((png_charp)chunk.name, (png_charp)png_ptr->chunk_name);
       chunk.data = (png_bytep)png_malloc(png_ptr, length);
       png_crc_read(png_ptr, chunk.data, length);
       chunk.size = length;
#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
       if(png_ptr->read_user_chunk_fn != NULL)
       {
          /* callback to user unknown chunk handler */
          if ((*(png_ptr->read_user_chunk_fn)) (png_ptr, &chunk) <= 0)
          {
             if (!(png_ptr->chunk_name[0] & 0x20))
                if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
                     PNG_HANDLE_CHUNK_ALWAYS)
                   png_chunk_error(png_ptr, "unknown critical chunk");
          }
             png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
       }
       else
#endif
          png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
       png_free(png_ptr, chunk.data);
   }
   else
#endif
      skip=length;
   png_push_crc_skip(png_ptr, skip);
}

void /* PRIVATE */
png_push_have_info(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr->info_fn != NULL)
      (*(png_ptr->info_fn))(png_ptr, info_ptr);
}

void /* PRIVATE */
png_push_have_end(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr->end_fn != NULL)
      (*(png_ptr->end_fn))(png_ptr, info_ptr);
}

void /* PRIVATE */
png_push_have_row(png_structp 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_structp png_ptr,
   png_bytep old_row, png_bytep new_row)
{
#ifdef PNG_USE_LOCAL_ARRAYS
   const int FARDATA png_pass_dsp_mask[7] =
      {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
#endif
   if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
      png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
}

void PNGAPI
png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
   png_progressive_end_ptr end_fn)
{
   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_structp png_ptr)
{
   return png_ptr->io_ptr;
}
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */