pngpread.c

一套图像处理程序,支持三种图像文件格式,我调试过了,很好用

}

void
png_push_read_tEXt(png_structp png_ptr, png_infop info)
{
   if (png_ptr->buffer_size && png_ptr->current_text_left)
   {
      png_uint_32 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_push_fill_buffer(png_ptr, (png_bytep)png_ptr->current_text_ptr,
         text_size);
      png_calculate_crc(png_ptr, (png_bytep)png_ptr->current_text_ptr,
         text_size);
      png_ptr->current_text_left -= text_size;
      png_ptr->current_text_ptr += (png_size_t)text_size;
   }
   if (!(png_ptr->current_text_left))
   {
      png_charp text;
      png_charp key;

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

      png_push_check_crc(png_ptr);

      key = png_ptr->current_text;
      png_ptr->current_text = 0;

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

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

      png_read_tEXt(png_ptr, info, key, text,
         png_ptr->current_text_size - (text - key));

      if (png_ptr->mode == PNG_AT_LAST_IDAT ||
         png_ptr->mode == PNG_AFTER_IDAT)
      {
         png_ptr->process_mode = PNG_READ_END_MODE;
      }
      else
      {
         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
      }
   }
}
#endif

#if defined(PNG_READ_zTXt_SUPPORTED)
void
png_push_handle_zTXt(png_structp png_ptr,
   png_uint_32 length)
{
   png_ptr->current_text = (png_charp)png_large_malloc(png_ptr, length + 1);
   png_ptr->current_text[(png_size_t)length] = '\0';
   png_ptr->current_text_ptr = png_ptr->current_text;
   png_ptr->current_text_size = length;
   png_ptr->current_text_left = length;
   png_ptr->process_mode = PNG_READ_zTXt_MODE;
}

void
png_push_read_zTXt(png_structp png_ptr, png_infop info)
{
   if (png_ptr->buffer_size && png_ptr->current_text_left)
   {
      png_uint_32 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_push_fill_buffer(png_ptr, (png_bytep)png_ptr->current_text_ptr,
         text_size);
      png_calculate_crc(png_ptr, (png_bytep)png_ptr->current_text_ptr,
         text_size);
      png_ptr->current_text_left -= text_size;
      png_ptr->current_text_ptr += (png_size_t)text_size;
   }
   if (!(png_ptr->current_text_left))
   {
      png_charp text;
      png_charp key;
      int ret;
      png_uint_32 text_size, key_size;

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

      png_push_check_crc(png_ptr);

      key = png_ptr->current_text;
      png_ptr->current_text = 0;

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

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

      text++;

      if (*text) /* check compression byte */
      {
         png_large_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 = (png_size_t)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_large_free(png_ptr, key);
            png_large_free(png_ptr, text);
            return;
         }
         if (!png_ptr->zstream->avail_out || ret == Z_STREAM_END)
         {
            if (!text)
            {
               text = (png_charp)png_large_malloc(png_ptr,
                  png_ptr->zbuf_size - png_ptr->zstream->avail_out +
                     key_size + 1);
               png_memcpy(text + (png_size_t)key_size, png_ptr->zbuf,
                  (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream->avail_out));
               png_memcpy(text, key, (png_size_t)key_size);
               text_size = key_size + (png_size_t)png_ptr->zbuf_size -
                  png_ptr->zstream->avail_out;
               *(text + (png_size_t)text_size) = '\0';
            }
            else
            {
               png_charp tmp;

               tmp = text;
               text = png_large_malloc(png_ptr, text_size +
                  png_ptr->zbuf_size - png_ptr->zstream->avail_out + 1);
               png_memcpy(text, tmp, (png_size_t)text_size);
               png_large_free(png_ptr, tmp);
               png_memcpy(text + (png_size_t)text_size, png_ptr->zbuf,
                  (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream->avail_out));
               text_size += png_ptr->zbuf_size - png_ptr->zstream->avail_out;
               *(text + (png_size_t)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_large_free(png_ptr, key);
         png_large_free(png_ptr, text);
         return;
      }

      png_large_free(png_ptr, key);
      key = text;
      text += (png_size_t)key_size;
      text_size -= key_size;

      png_read_zTXt(png_ptr, info, key, text, text_size, 0);
      if (png_ptr->mode == PNG_AT_LAST_IDAT ||
         png_ptr->mode == PNG_AFTER_IDAT)
      {
         png_ptr->process_mode = PNG_READ_END_MODE;
      }
      else
      {
         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
      }
   }
}
#endif

void
png_push_have_info(png_structp png_ptr, png_infop info)
{
   if (png_ptr->info_fn)
      (*(png_ptr->info_fn))(png_ptr, info);
}

void
png_push_have_end(png_structp png_ptr, png_infop info)
{
   if (png_ptr->end_fn)
      (*(png_ptr->end_fn))(png_ptr, info);
}

void
png_push_have_row(png_structp png_ptr, png_bytep row)
{
   if (png_ptr->row_fn)
      (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
         (int)png_ptr->pass);
}

png_voidp
png_get_progressive_ptr(png_structp png_ptr)
{
   return png_ptr->io_ptr;
}

void
png_push_read_end(png_structp png_ptr, png_infop info)
{
   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
   {
      png_byte chunk_start[8];

      if (png_ptr->buffer_size < 8)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_push_fill_buffer(png_ptr, chunk_start, 8);
      png_ptr->push_length = png_get_uint_32(chunk_start);
      png_memcpy(png_ptr->push_chunk_name, (png_voidp)(chunk_start + 4), 4);
      png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
      png_reset_crc(png_ptr);
      png_calculate_crc(png_ptr, chunk_start + 4, 4);
   }

   if (!png_memcmp(png_ptr->push_chunk_name, png_IHDR, 4))
   {
      png_error(png_ptr, "Invalid IHDR after IDAT");
   }
   else if (!png_memcmp(png_ptr->push_chunk_name, png_PLTE, 4))
   {
      png_error(png_ptr, "Invalid PLTE after IDAT");
   }
   else if (!png_memcmp(png_ptr->push_chunk_name, png_IDAT, 4))
   {
      if (png_ptr->push_length > 0 || png_ptr->mode != PNG_AT_LAST_IDAT)
         png_error(png_ptr, "Too many IDAT's found");
   }
   else if (!png_memcmp(png_ptr->push_chunk_name, png_IEND, 4))
   {
      if (png_ptr->push_length)
         png_error(png_ptr, "Invalid IEND chunk");
      if (png_ptr->buffer_size < 4)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_push_check_crc(png_ptr);
      png_ptr->mode = PNG_AFTER_IEND;
      png_ptr->process_mode = PNG_READ_DONE_MODE;
      png_push_have_end(png_ptr, info);
   }
#if defined(PNG_READ_gAMA_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_gAMA, 4))
   {
      png_error(png_ptr, "Invalid gAMA after IDAT");
   }
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_sBIT, 4))
   {
      png_error(png_ptr, "Invalid sBIT after IDAT");
   }
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_cHRM, 4))
   {
      png_error(png_ptr, "Invalid cHRM after IDAT");
   }
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_tRNS, 4))
   {
      png_error(png_ptr, "Invalid tRNS after IDAT");
   }
#endif
#if defined(PNG_READ_bKGD_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_bKGD, 4))
   {
      png_error(png_ptr, "Invalid bKGD after IDAT");
   }
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_hIST, 4))
   {
      png_error(png_ptr, "Invalid hIST after IDAT");
   }
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_pHYs, 4))
   {
      png_error(png_ptr, "Invalid pHYs after IDAT");
   }
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_oFFs, 4))
   {
      png_error(png_ptr, "Invalid oFFs after IDAT");
   }
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_tIME, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      if (png_ptr->mode == PNG_BEFORE_IHDR ||
         png_ptr->mode == PNG_AFTER_IEND)
         png_error(png_ptr, "Out of place tIME");

      png_handle_tIME(png_ptr, info, png_ptr->push_length);
      png_push_check_crc(png_ptr);
   }
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_tEXt, 4))
   {
      if (png_ptr->mode == PNG_BEFORE_IHDR ||
         png_ptr->mode == PNG_AFTER_IEND)
         png_error(png_ptr, "Out of place tEXt");

      png_push_handle_tEXt(png_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
   else if (!png_memcmp(png_ptr->push_chunk_name, png_zTXt, 4))
   {
      if (png_ptr->mode == PNG_BEFORE_IHDR ||
         png_ptr->mode == PNG_AFTER_IEND)
         png_error(png_ptr, "Out of place zTXt");

      png_push_handle_zTXt(png_ptr, png_ptr->push_length);
   }
#endif
   else
   {
      if (png_ptr->push_chunk_name[0] <41 || png_ptr->push_chunk_name[0]> 122 ||
          (png_ptr->push_chunk_name[0]>90 && png_ptr->push_chunk_name[0]< 97) ||
          png_ptr->push_chunk_name[1] <41 || png_ptr->push_chunk_name[1]> 122 ||
          (png_ptr->push_chunk_name[1]>90 && png_ptr->push_chunk_name[1]< 97) ||
          png_ptr->push_chunk_name[2] <41 || png_ptr->push_chunk_name[2]> 122 ||
          (png_ptr->push_chunk_name[2]>90 && png_ptr->push_chunk_name[2]< 97) ||
          png_ptr->push_chunk_name[3] <41 || png_ptr->push_chunk_name[3]> 122 ||
          (png_ptr->push_chunk_name[3]>90 && png_ptr->push_chunk_name[3]< 97))
      {
         char msg[45];

         sprintf(msg, "Invalid chunk type 0x%02X 0x%02X 0x%02X 0x%02X",
            png_ptr->push_chunk_name[0], png_ptr->push_chunk_name[1],
            png_ptr->push_chunk_name[2], png_ptr->push_chunk_name[3]);
         png_error(png_ptr, msg);
      }

      if ((png_ptr->push_chunk_name[0] & 0x20) == 0)
      {
         char msg[40];

         sprintf(msg, "Unknown critical chunk %c%c%c%c",
            png_ptr->push_chunk_name[0], png_ptr->push_chunk_name[1],
            png_ptr->push_chunk_name[2], png_ptr->push_chunk_name[3]);
         png_error(png_ptr, msg);
      }

      png_push_crc_skip(png_ptr, png_ptr->push_length);
   }
   if (png_ptr->mode == PNG_AT_LAST_IDAT)
      png_ptr->mode = PNG_AFTER_IDAT;
   png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
}

void
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);
}

void
png_progressive_combine_row (png_structp png_ptr,
   png_bytep old_row, png_bytep new_row)
{
   if (new_row)
      png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
}

#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */