text: 
  /* pngset.c - storage of image information into info struct
   *
   * Last changed in libpng 1.6.35 [July 15, 2018]
   * Copyright (c) 1998-2018 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
   *
   * The functions here are used during reads to store data from the file
   * into the info struct, and during writes to store application data
   * into the info struct for writing into the file.  This abstracts the
   * info struct and allows us to change the structure in the future.
   */
  
  #include "pngpriv.h"
  
  #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
  
  #ifdef PNG_bKGD_SUPPORTED
  void PNGAPI
  png_set_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_color_16p background)
  {
     png_debug1(1, "in %s storage function", "bKGD");
  
     if (png_ptr == NULL || info_ptr == NULL || background == NULL)
        return;
  
     info_ptr->background = *background;
     info_ptr->valid |= PNG_INFO_bKGD;
  }
  #endif
  
  #ifdef PNG_cHRM_SUPPORTED
  void PNGFAPI
  png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
      png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
      png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
      png_fixed_point blue_x, png_fixed_point blue_y)
  {
     png_xy xy;
  
     png_debug1(1, "in %s storage function", "cHRM fixed");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     xy.redx = red_x;
     xy.redy = red_y;
     xy.greenx = green_x;
     xy.greeny = green_y;
     xy.bluex = blue_x;
     xy.bluey = blue_y;
     xy.whitex = white_x;
     xy.whitey = white_y;
  
     if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
         2/* override with app values*/) != 0)
        info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
  
     png_colorspace_sync_info(png_ptr, info_ptr);
  }
  
  void PNGFAPI
  png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
      png_fixed_point int_red_X, png_fixed_point int_red_Y,
      png_fixed_point int_red_Z, png_fixed_point int_green_X,
      png_fixed_point int_green_Y, png_fixed_point int_green_Z,
      png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
      png_fixed_point int_blue_Z)
  {
     png_XYZ XYZ;
  
     png_debug1(1, "in %s storage function", "cHRM XYZ fixed");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     XYZ.red_X = int_red_X;
     XYZ.red_Y = int_red_Y;
     XYZ.red_Z = int_red_Z;
     XYZ.green_X = int_green_X;
     XYZ.green_Y = int_green_Y;
     XYZ.green_Z = int_green_Z;
     XYZ.blue_X = int_blue_X;
     XYZ.blue_Y = int_blue_Y;
     XYZ.blue_Z = int_blue_Z;
  
     if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
         &XYZ, 2) != 0)
        info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
  
     png_colorspace_sync_info(png_ptr, info_ptr);
  }
  
  #  ifdef PNG_FLOATING_POINT_SUPPORTED
  void PNGAPI
  png_set_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
      double white_x, double white_y, double red_x, double red_y,
      double green_x, double green_y, double blue_x, double blue_y)
  {
     png_set_cHRM_fixed(png_ptr, info_ptr,
         png_fixed(png_ptr, white_x, "cHRM White X"),
         png_fixed(png_ptr, white_y, "cHRM White Y"),
         png_fixed(png_ptr, red_x, "cHRM Red X"),
         png_fixed(png_ptr, red_y, "cHRM Red Y"),
         png_fixed(png_ptr, green_x, "cHRM Green X"),
         png_fixed(png_ptr, green_y, "cHRM Green Y"),
         png_fixed(png_ptr, blue_x, "cHRM Blue X"),
         png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
  }
  
  void PNGAPI
  png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
      double red_Y, double red_Z, double green_X, double green_Y, double green_Z,
      double blue_X, double blue_Y, double blue_Z)
  {
     png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
         png_fixed(png_ptr, red_X, "cHRM Red X"),
         png_fixed(png_ptr, red_Y, "cHRM Red Y"),
         png_fixed(png_ptr, red_Z, "cHRM Red Z"),
         png_fixed(png_ptr, green_X, "cHRM Green X"),
         png_fixed(png_ptr, green_Y, "cHRM Green Y"),
         png_fixed(png_ptr, green_Z, "cHRM Green Z"),
         png_fixed(png_ptr, blue_X, "cHRM Blue X"),
         png_fixed(png_ptr, blue_Y, "cHRM Blue Y"),
         png_fixed(png_ptr, blue_Z, "cHRM Blue Z"));
  }
  #  endif /* FLOATING_POINT */
  
  #endif /* cHRM */
  
  #ifdef PNG_eXIf_SUPPORTED
  void PNGAPI
  png_set_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,
      const png_bytep eXIf_buf)
  {
    png_warning(png_ptr, "png_set_eXIf does not work; use png_set_eXIf_1");
    PNG_UNUSED(info_ptr)
    PNG_UNUSED(eXIf_buf)
  }
  
  void PNGAPI
  png_set_eXIf_1(png_const_structrp png_ptr, png_inforp info_ptr,
      const png_uint_32 num_exif, const png_bytep eXIf_buf)
  {
     int i;
  
     png_debug1(1, "in %s storage function", "eXIf");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     if (info_ptr->exif)
     {
        png_free(png_ptr, info_ptr->exif);
        info_ptr->exif = NULL;
     }
  
     info_ptr->num_exif = num_exif;
  
     info_ptr->exif = png_voidcast(png_bytep, png_malloc_warn(png_ptr,
         info_ptr->num_exif));
  
     if (info_ptr->exif == NULL)
     {
        png_warning(png_ptr, "Insufficient memory for eXIf chunk data");
        return;
     }
  
     info_ptr->free_me |= PNG_FREE_EXIF;
  
     for (i = 0; i < (int) info_ptr->num_exif; i++)
        info_ptr->exif[i] = eXIf_buf[i];
  
     info_ptr->valid |= PNG_INFO_eXIf;
  }
  #endif /* eXIf */
  
  #ifdef PNG_gAMA_SUPPORTED
  void PNGFAPI
  png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
      png_fixed_point file_gamma)
  {
     png_debug1(1, "in %s storage function", "gAMA");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     png_colorspace_set_gamma(png_ptr, &info_ptr->colorspace, file_gamma);
     png_colorspace_sync_info(png_ptr, info_ptr);
  }
  
  #  ifdef PNG_FLOATING_POINT_SUPPORTED
  void PNGAPI
  png_set_gAMA(png_const_structrp png_ptr, png_inforp info_ptr, double file_gamma)
  {
     png_set_gAMA_fixed(png_ptr, info_ptr, png_fixed(png_ptr, file_gamma,
         "png_set_gAMA"));
  }
  #  endif
  #endif
  
  #ifdef PNG_hIST_SUPPORTED
  void PNGAPI
  png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_uint_16p hist)
  {
     int i;
  
     png_debug1(1, "in %s storage function", "hIST");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     if (info_ptr->num_palette == 0 || info_ptr->num_palette
         > PNG_MAX_PALETTE_LENGTH)
     {
        png_warning(png_ptr,
            "Invalid palette size, hIST allocation skipped");
  
        return;
     }
  
     png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
  
     /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in
      * version 1.2.1
      */
     info_ptr->hist = png_voidcast(png_uint_16p, png_malloc_warn(png_ptr,
         PNG_MAX_PALETTE_LENGTH * (sizeof (png_uint_16))));
  
     if (info_ptr->hist == NULL)
     {
        png_warning(png_ptr, "Insufficient memory for hIST chunk data");
  
        return;
     }
  
     info_ptr->free_me |= PNG_FREE_HIST;
  
     for (i = 0; i < info_ptr->num_palette; i++)
        info_ptr->hist[i] = hist[i];
  
     info_ptr->valid |= PNG_INFO_hIST;
  }
  #endif
  
  void PNGAPI
  png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
      png_uint_32 width, png_uint_32 height, int bit_depth,
      int color_type, int interlace_type, int compression_type,
      int filter_type)
  {
     png_debug1(1, "in %s storage function", "IHDR");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     info_ptr->width = width;
     info_ptr->height = height;
     info_ptr->bit_depth = (png_byte)bit_depth;
     info_ptr->color_type = (png_byte)color_type;
     info_ptr->compression_type = (png_byte)compression_type;
     info_ptr->filter_type = (png_byte)filter_type;
     info_ptr->interlace_type = (png_byte)interlace_type;
  
     png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height,
         info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
         info_ptr->compression_type, info_ptr->filter_type);
  
     if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
        info_ptr->channels = 1;
  
     else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
        info_ptr->channels = 3;
  
     else
        info_ptr->channels = 1;
  
     if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
        info_ptr->channels++;
  
     info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
  
     info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
  }
  
  #ifdef PNG_oFFs_SUPPORTED
  void PNGAPI
  png_set_oFFs(png_const_structrp png_ptr, png_inforp info_ptr,
      png_int_32 offset_x, png_int_32 offset_y, int unit_type)
  {
     png_debug1(1, "in %s storage function", "oFFs");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     info_ptr->x_offset = offset_x;
     info_ptr->y_offset = offset_y;
     info_ptr->offset_unit_type = (png_byte)unit_type;
     info_ptr->valid |= PNG_INFO_oFFs;
  }
  #endif
  
  #ifdef PNG_pCAL_SUPPORTED
  void PNGAPI
  png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
      int nparams, png_const_charp units, png_charpp params)
  {
     size_t length;
     int i;
  
     png_debug1(1, "in %s storage function", "pCAL");
  
     if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL
         || (nparams > 0 && params == NULL))
        return;
  
     length = strlen(purpose) + 1;
     png_debug1(3, "allocating purpose for info (%lu bytes)",
         (unsigned long)length);
  
     /* TODO: validate format of calibration name and unit name */
  
     /* Check that the type matches the specification. */
     if (type < 0 || type > 3)
     {
        png_chunk_report(png_ptr, "Invalid pCAL equation type",
              PNG_CHUNK_WRITE_ERROR);
        return;
     }
  
     if (nparams < 0 || nparams > 255)
     {
        png_chunk_report(png_ptr, "Invalid pCAL parameter count",
              PNG_CHUNK_WRITE_ERROR);
        return;
     }
  
     /* Validate params[nparams] */
     for (i=0; i<nparams; ++i)
     {
        if (params[i] == NULL ||
            !png_check_fp_string(params[i], strlen(params[i])))
        {
           png_chunk_report(png_ptr, "Invalid format for pCAL parameter",
                 PNG_CHUNK_WRITE_ERROR);
           return;
        }
     }
  
     info_ptr->pcal_purpose = png_voidcast(png_charp,
         png_malloc_warn(png_ptr, length));
  
     if (info_ptr->pcal_purpose == NULL)
     {
        png_chunk_report(png_ptr, "Insufficient memory for pCAL purpose",
              PNG_CHUNK_WRITE_ERROR);
        return;
     }
  
     memcpy(info_ptr->pcal_purpose, purpose, length);
  
     png_debug(3, "storing X0, X1, type, and nparams in info");
     info_ptr->pcal_X0 = X0;
     info_ptr->pcal_X1 = X1;
     info_ptr->pcal_type = (png_byte)type;
     info_ptr->pcal_nparams = (png_byte)nparams;
  
     length = strlen(units) + 1;
     png_debug1(3, "allocating units for info (%lu bytes)",
         (unsigned long)length);
  
     info_ptr->pcal_units = png_voidcast(png_charp,
         png_malloc_warn(png_ptr, length));
  
     if (info_ptr->pcal_units == NULL)
     {
        png_warning(png_ptr, "Insufficient memory for pCAL units");
  
        return;
     }
  
     memcpy(info_ptr->pcal_units, units, length);
  
     info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
         (size_t)(((unsigned int)nparams + 1) * (sizeof (png_charp)))));
  
     if (info_ptr->pcal_params == NULL)
     {
        png_warning(png_ptr, "Insufficient memory for pCAL params");
  
        return;
     }
  
     memset(info_ptr->pcal_params, 0, ((unsigned int)nparams + 1) *
         (sizeof (png_charp)));
  
     for (i = 0; i < nparams; i++)
     {
        length = strlen(params[i]) + 1;
        png_debug2(3, "allocating parameter %d for info (%lu bytes)", i,
            (unsigned long)length);
  
        info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length);
  
        if (info_ptr->pcal_params[i] == NULL)
        {
           png_warning(png_ptr, "Insufficient memory for pCAL parameter");
  
           return;
        }
  
        memcpy(info_ptr->pcal_params[i], params[i], length);
     }
  
     info_ptr->valid |= PNG_INFO_pCAL;
     info_ptr->free_me |= PNG_FREE_PCAL;
  }
  #endif
  
  #ifdef PNG_sCAL_SUPPORTED
  void PNGAPI
  png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
      int unit, png_const_charp swidth, png_const_charp sheight)
  {
     size_t lengthw = 0, lengthh = 0;
  
     png_debug1(1, "in %s storage function", "sCAL");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     /* Double check the unit (should never get here with an invalid
      * unit unless this is an API call.)
      */
     if (unit != 1 && unit != 2)
        png_error(png_ptr, "Invalid sCAL unit");
  
     if (swidth == NULL || (lengthw = strlen(swidth)) == 0 ||
         swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
        png_error(png_ptr, "Invalid sCAL width");
  
     if (sheight == NULL || (lengthh = strlen(sheight)) == 0 ||
         sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
        png_error(png_ptr, "Invalid sCAL height");
  
     info_ptr->scal_unit = (png_byte)unit;
  
     ++lengthw;
  
     png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw);
  
     info_ptr->scal_s_width = png_voidcast(png_charp,
         png_malloc_warn(png_ptr, lengthw));
  
     if (info_ptr->scal_s_width == NULL)
     {
        png_warning(png_ptr, "Memory allocation failed while processing sCAL");
  
        return;
     }
  
     memcpy(info_ptr->scal_s_width, swidth, lengthw);
  
     ++lengthh;
  
     png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh);
  
     info_ptr->scal_s_height = png_voidcast(png_charp,
         png_malloc_warn(png_ptr, lengthh));
  
     if (info_ptr->scal_s_height == NULL)
     {
        png_free (png_ptr, info_ptr->scal_s_width);
        info_ptr->scal_s_width = NULL;
  
        png_warning(png_ptr, "Memory allocation failed while processing sCAL");
  
        return;
     }
  
     memcpy(info_ptr->scal_s_height, sheight, lengthh);
  
     info_ptr->valid |= PNG_INFO_sCAL;
     info_ptr->free_me |= PNG_FREE_SCAL;
  }
  
  #  ifdef PNG_FLOATING_POINT_SUPPORTED
  void PNGAPI
  png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
      double width, double height)
  {
     png_debug1(1, "in %s storage function", "sCAL");
  
     /* Check the arguments. */
     if (width <= 0)
        png_warning(png_ptr, "Invalid sCAL width ignored");
  
     else if (height <= 0)
        png_warning(png_ptr, "Invalid sCAL height ignored");
  
     else
     {
        /* Convert 'width' and 'height' to ASCII. */
        char swidth[PNG_sCAL_MAX_DIGITS+1];
        char sheight[PNG_sCAL_MAX_DIGITS+1];
  
        png_ascii_from_fp(png_ptr, swidth, (sizeof swidth), width,
            PNG_sCAL_PRECISION);
        png_ascii_from_fp(png_ptr, sheight, (sizeof sheight), height,
            PNG_sCAL_PRECISION);
  
        png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
     }
  }
  #  endif
  
  #  ifdef PNG_FIXED_POINT_SUPPORTED
  void PNGAPI
  png_set_sCAL_fixed(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
      png_fixed_point width, png_fixed_point height)
  {
     png_debug1(1, "in %s storage function", "sCAL");
  
     /* Check the arguments. */
     if (width <= 0)
        png_warning(png_ptr, "Invalid sCAL width ignored");
  
     else if (height <= 0)
        png_warning(png_ptr, "Invalid sCAL height ignored");
  
     else
     {
        /* Convert 'width' and 'height' to ASCII. */
        char swidth[PNG_sCAL_MAX_DIGITS+1];
        char sheight[PNG_sCAL_MAX_DIGITS+1];
  
        png_ascii_from_fixed(png_ptr, swidth, (sizeof swidth), width);
        png_ascii_from_fixed(png_ptr, sheight, (sizeof sheight), height);
  
        png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
     }
  }
  #  endif
  #endif
  
  #ifdef PNG_pHYs_SUPPORTED
  void PNGAPI
  png_set_pHYs(png_const_structrp png_ptr, png_inforp info_ptr,
      png_uint_32 res_x, png_uint_32 res_y, int unit_type)
  {
     png_debug1(1, "in %s storage function", "pHYs");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     info_ptr->x_pixels_per_unit = res_x;
     info_ptr->y_pixels_per_unit = res_y;
     info_ptr->phys_unit_type = (png_byte)unit_type;
     info_ptr->valid |= PNG_INFO_pHYs;
  }
  #endif
  
  void PNGAPI
  png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
      png_const_colorp palette, int num_palette)
  {
  
     png_uint_32 max_palette_length;
  
     png_debug1(1, "in %s storage function", "PLTE");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     max_palette_length = (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
        (1 << info_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
  
     if (num_palette < 0 || num_palette > (int) max_palette_length)
     {
        if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
           png_error(png_ptr, "Invalid palette length");
  
        else
        {
           png_warning(png_ptr, "Invalid palette length");
  
           return;
        }
     }
  
     if ((num_palette > 0 && palette == NULL) ||
        (num_palette == 0
  #        ifdef PNG_MNG_FEATURES_SUPPORTED
              && (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0
  #        endif
        ))
     {
        png_error(png_ptr, "Invalid palette");
     }
  
     /* It may not actually be necessary to set png_ptr->palette here;
      * we do it for backward compatibility with the way the png_handle_tRNS
      * function used to do the allocation.
      *
      * 1.6.0: the above statement appears to be incorrect; something has to set
      * the palette inside png_struct on read.
      */
     png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
  
     /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
      * of num_palette entries, in case of an invalid PNG file or incorrect
      * call to png_set_PLTE() with too-large sample values.
      */
     png_ptr->palette = png_voidcast(png_colorp, png_calloc(png_ptr,
         PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));
  
     if (num_palette > 0)
        memcpy(png_ptr->palette, palette, (unsigned int)num_palette *
            (sizeof (png_color)));
     info_ptr->palette = png_ptr->palette;
     info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;
  
     info_ptr->free_me |= PNG_FREE_PLTE;
  
     info_ptr->valid |= PNG_INFO_PLTE;
  }
  
  #ifdef PNG_sBIT_SUPPORTED
  void PNGAPI
  png_set_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_color_8p sig_bit)
  {
     png_debug1(1, "in %s storage function", "sBIT");
  
     if (png_ptr == NULL || info_ptr == NULL || sig_bit == NULL)
        return;
  
     info_ptr->sig_bit = *sig_bit;
     info_ptr->valid |= PNG_INFO_sBIT;
  }
  #endif
  
  #ifdef PNG_sRGB_SUPPORTED
  void PNGAPI
  png_set_sRGB(png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)
  {
     png_debug1(1, "in %s storage function", "sRGB");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     (void)png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent);
     png_colorspace_sync_info(png_ptr, info_ptr);
  }
  
  void PNGAPI
  png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
      int srgb_intent)
  {
     png_debug1(1, "in %s storage function", "sRGB_gAMA_and_cHRM");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
         srgb_intent) != 0)
     {
        /* This causes the gAMA and cHRM to be written too */
        info_ptr->colorspace.flags |=
           PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
     }
  
     png_colorspace_sync_info(png_ptr, info_ptr);
  }
  #endif /* sRGB */
  
  
  #ifdef PNG_iCCP_SUPPORTED
  void PNGAPI
  png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_charp name, int compression_type,
      png_const_bytep profile, png_uint_32 proflen)
  {
     png_charp new_iccp_name;
     png_bytep new_iccp_profile;
     size_t length;
  
     png_debug1(1, "in %s storage function", "iCCP");
  
     if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
        return;
  
     if (compression_type != PNG_COMPRESSION_TYPE_BASE)
        png_app_error(png_ptr, "Invalid iCCP compression method");
  
     /* Set the colorspace first because this validates the profile; do not
      * override previously set app cHRM or gAMA here (because likely as not the
      * application knows better than libpng what the correct values are.)  Pass
      * the info_ptr color_type field to png_colorspace_set_ICC because in the
      * write case it has not yet been stored in png_ptr.
      */
     {
        int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name,
            proflen, profile, info_ptr->color_type);
  
        png_colorspace_sync_info(png_ptr, info_ptr);
  
        /* Don't do any of the copying if the profile was bad, or inconsistent. */
        if (result == 0)
           return;
  
        /* But do write the gAMA and cHRM chunks from the profile. */
        info_ptr->colorspace.flags |=
           PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
     }
  
     length = strlen(name)+1;
     new_iccp_name = png_voidcast(png_charp, png_malloc_warn(png_ptr, length));
  
     if (new_iccp_name == NULL)
     {
        png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk");
  
        return;
     }
  
     memcpy(new_iccp_name, name, length);
     new_iccp_profile = png_voidcast(png_bytep,
         png_malloc_warn(png_ptr, proflen));
  
     if (new_iccp_profile == NULL)
     {
        png_free(png_ptr, new_iccp_name);
        png_benign_error(png_ptr,
            "Insufficient memory to process iCCP profile");
  
        return;
     }
  
     memcpy(new_iccp_profile, profile, proflen);
  
     png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);
  
     info_ptr->iccp_proflen = proflen;
     info_ptr->iccp_name = new_iccp_name;
     info_ptr->iccp_profile = new_iccp_profile;
     info_ptr->free_me |= PNG_FREE_ICCP;
     info_ptr->valid |= PNG_INFO_iCCP;
  }
  #endif
  
  #ifdef PNG_TEXT_SUPPORTED
  void PNGAPI
  png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_textp text_ptr, int num_text)
  {
     int ret;
     ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);
  
     if (ret != 0)
        png_error(png_ptr, "Insufficient memory to store text");
  }
  
  int /* PRIVATE */
  png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_textp text_ptr, int num_text)
  {
     int i;
  
     png_debug1(1, "in %lx storage function", png_ptr == NULL ? 0xabadca11U :
        (unsigned long)png_ptr->chunk_name);
  
     if (png_ptr == NULL || info_ptr == NULL || num_text <= 0 || text_ptr == NULL)
        return(0);
  
     /* Make sure we have enough space in the "text" array in info_struct
      * to hold all of the incoming text_ptr objects.  This compare can't overflow
      * because max_text >= num_text (anyway, subtract of two positive integers
      * can't overflow in any case.)
      */
     if (num_text > info_ptr->max_text - info_ptr->num_text)
     {
        int old_num_text = info_ptr->num_text;
        int max_text;
        png_textp new_text = NULL;
  
        /* Calculate an appropriate max_text, checking for overflow. */
        max_text = old_num_text;
        if (num_text <= INT_MAX - max_text)
        {
           max_text += num_text;
  
           /* Round up to a multiple of 8 */
           if (max_text < INT_MAX-8)
              max_text = (max_text + 8) & ~0x7;
  
           else
              max_text = INT_MAX;
  
           /* Now allocate a new array and copy the old members in; this does all
            * the overflow checks.
            */
           new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
               info_ptr->text, old_num_text, max_text-old_num_text,
               sizeof *new_text));
        }
  
        if (new_text == NULL)
        {
           png_chunk_report(png_ptr, "too many text chunks",
               PNG_CHUNK_WRITE_ERROR);
  
           return 1;
        }
  
        png_free(png_ptr, info_ptr->text);
  
        info_ptr->text = new_text;
        info_ptr->free_me |= PNG_FREE_TEXT;
        info_ptr->max_text = max_text;
        /* num_text is adjusted below as the entries are copied in */
  
        png_debug1(3, "allocated %d entries for info_ptr->text", max_text);
     }
  
     for (i = 0; i < num_text; i++)
     {
        size_t text_length, key_len;
        size_t lang_len, lang_key_len;
        png_textp textp = &(info_ptr->text[info_ptr->num_text]);
  
        if (text_ptr[i].key == NULL)
            continue;
  
        if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE ||
            text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
        {
           png_chunk_report(png_ptr, "text compression mode is out of range",
               PNG_CHUNK_WRITE_ERROR);
           continue;
        }
  
        key_len = strlen(text_ptr[i].key);
  
        if (text_ptr[i].compression <= 0)
        {
           lang_len = 0;
           lang_key_len = 0;
        }
  
        else
  #  ifdef PNG_iTXt_SUPPORTED
        {
           /* Set iTXt data */
  
           if (text_ptr[i].lang != NULL)
              lang_len = strlen(text_ptr[i].lang);
  
           else
              lang_len = 0;
  
           if (text_ptr[i].lang_key != NULL)
              lang_key_len = strlen(text_ptr[i].lang_key);
  
           else
              lang_key_len = 0;
        }
  #  else /* iTXt */
        {
           png_chunk_report(png_ptr, "iTXt chunk not supported",
               PNG_CHUNK_WRITE_ERROR);
           continue;
        }
  #  endif
  
        if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
        {
           text_length = 0;
  #  ifdef PNG_iTXt_SUPPORTED
           if (text_ptr[i].compression > 0)
              textp->compression = PNG_ITXT_COMPRESSION_NONE;
  
           else
  #  endif
              textp->compression = PNG_TEXT_COMPRESSION_NONE;
        }
  
        else
        {
           text_length = strlen(text_ptr[i].text);
           textp->compression = text_ptr[i].compression;
        }
  
        textp->key = png_voidcast(png_charp,png_malloc_base(png_ptr,
            key_len + text_length + lang_len + lang_key_len + 4));
  
        if (textp->key == NULL)
        {
           png_chunk_report(png_ptr, "text chunk: out of memory",
               PNG_CHUNK_WRITE_ERROR);
  
           return 1;
        }
  
        png_debug2(2, "Allocated %lu bytes at %p in png_set_text",
            (unsigned long)(png_uint_32)
            (key_len + lang_len + lang_key_len + text_length + 4),
            textp->key);
  
        memcpy(textp->key, text_ptr[i].key, key_len);
        *(textp->key + key_len) = '\0';
  
        if (text_ptr[i].compression > 0)
        {
           textp->lang = textp->key + key_len + 1;
           memcpy(textp->lang, text_ptr[i].lang, lang_len);
           *(textp->lang + lang_len) = '\0';
           textp->lang_key = textp->lang + lang_len + 1;
           memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
           *(textp->lang_key + lang_key_len) = '\0';
           textp->text = textp->lang_key + lang_key_len + 1;
        }
  
        else
        {
           textp->lang=NULL;
           textp->lang_key=NULL;
           textp->text = textp->key + key_len + 1;
        }
  
        if (text_length != 0)
           memcpy(textp->text, text_ptr[i].text, text_length);
  
        *(textp->text + text_length) = '\0';
  
  #  ifdef PNG_iTXt_SUPPORTED
        if (textp->compression > 0)
        {
           textp->text_length = 0;
           textp->itxt_length = text_length;
        }
  
        else
  #  endif
        {
           textp->text_length = text_length;
           textp->itxt_length = 0;
        }
  
        info_ptr->num_text++;
        png_debug1(3, "transferred text chunk %d", info_ptr->num_text);
     }
  
     return(0);
  }
  #endif
  
  #ifdef PNG_tIME_SUPPORTED
  void PNGAPI
  png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
      png_const_timep mod_time)
  {
     png_debug1(1, "in %s storage function", "tIME");
  
     if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
         (png_ptr->mode & PNG_WROTE_tIME) != 0)
        return;
  
     if (mod_time->month == 0   || mod_time->month > 12  ||
         mod_time->day   == 0   || mod_time->day   > 31  ||
         mod_time->hour  > 23   || mod_time->minute > 59 ||
         mod_time->second > 60)
     {
        png_warning(png_ptr, "Ignoring invalid time value");
  
        return;
     }
  
     info_ptr->mod_time = *mod_time;
     info_ptr->valid |= PNG_INFO_tIME;
  }
  #endif
  
  #ifdef PNG_tRNS_SUPPORTED
  void PNGAPI
  png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
      png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color)
  {
     png_debug1(1, "in %s storage function", "tRNS");
  
     if (png_ptr == NULL || info_ptr == NULL)
  
        return;
  
     if (trans_alpha != NULL)
     {
         /* It may not actually be necessary to set png_ptr->trans_alpha here;
          * we do it for backward compatibility with the way the png_handle_tRNS
          * function used to do the allocation.
          *
          * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively
          * relies on png_set_tRNS storing the information in png_struct
          * (otherwise it won't be there for the code in pngrtran.c).
          */
  
         png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
  
         if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
         {
           /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
            info_ptr->trans_alpha = png_voidcast(png_bytep,
                png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
            memcpy(info_ptr->trans_alpha, trans_alpha, (size_t)num_trans);
         }
         png_ptr->trans_alpha = info_ptr->trans_alpha;
     }
  
     if (trans_color != NULL)
     {
  #ifdef PNG_WARNINGS_SUPPORTED
        if (info_ptr->bit_depth < 16)
        {
           int sample_max = (1 << info_ptr->bit_depth) - 1;
  
           if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
               trans_color->gray > sample_max) ||
               (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
               (trans_color->red > sample_max ||
               trans_color->green > sample_max ||
               trans_color->blue > sample_max)))
              png_warning(png_ptr,
                  "tRNS chunk has out-of-range samples for bit_depth");
        }
  #endif
  
        info_ptr->trans_color = *trans_color;
  
        if (num_trans == 0)
           num_trans = 1;
     }
  
     info_ptr->num_trans = (png_uint_16)num_trans;
  
     if (num_trans != 0)
     {
        info_ptr->valid |= PNG_INFO_tRNS;
        info_ptr->free_me |= PNG_FREE_TRNS;
     }
  }
  #endif
  
  #ifdef PNG_sPLT_SUPPORTED
  void PNGAPI
  png_set_sPLT(png_const_structrp png_ptr,
      png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)
  /*
   *  entries        - array of png_sPLT_t structures
   *                   to be added to the list of palettes
   *                   in the info structure.
   *
   *  nentries       - number of palette structures to be
   *                   added.
   */
  {
     png_sPLT_tp np;
  
     if (png_ptr == NULL || info_ptr == NULL || nentries <= 0 || entries == NULL)
        return;
  
     /* Use the internal realloc function, which checks for all the possible
      * overflows.  Notice that the parameters are (int) and (size_t)
      */
     np = png_voidcast(png_sPLT_tp,png_realloc_array(png_ptr,
         info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries,
         sizeof *np));
  
     if (np == NULL)
     {
        /* Out of memory or too many chunks */
        png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);
  
        return;
     }
  
     png_free(png_ptr, info_ptr->splt_palettes);
     info_ptr->splt_palettes = np;
     info_ptr->free_me |= PNG_FREE_SPLT;
  
     np += info_ptr->splt_palettes_num;
  
     do
     {
        size_t length;
  
        /* Skip invalid input entries */
        if (entries->name == NULL || entries->entries == NULL)
        {
           /* png_handle_sPLT doesn't do this, so this is an app error */
           png_app_error(png_ptr, "png_set_sPLT: invalid sPLT");
           /* Just skip the invalid entry */
           continue;
        }
  
        np->depth = entries->depth;
  
        /* In the event of out-of-memory just return - there's no point keeping
         * on trying to add sPLT chunks.
         */
        length = strlen(entries->name) + 1;
        np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));
  
        if (np->name == NULL)
           break;
  
        memcpy(np->name, entries->name, length);
  
        /* IMPORTANT: we have memory now that won't get freed if something else
         * goes wrong; this code must free it.  png_malloc_array produces no
         * warnings; use a png_chunk_report (below) if there is an error.
         */
        np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
            entries->nentries, sizeof (png_sPLT_entry)));
  
        if (np->entries == NULL)
        {
           png_free(png_ptr, np->name);
           np->name = NULL;
           break;
        }
  
        np->nentries = entries->nentries;
        /* This multiply can't overflow because png_malloc_array has already
         * checked it when doing the allocation.
         */
        memcpy(np->entries, entries->entries,
            (unsigned int)entries->nentries * sizeof (png_sPLT_entry));
  
        /* Note that 'continue' skips the advance of the out pointer and out
         * count, so an invalid entry is not added.
         */
        info_ptr->valid |= PNG_INFO_sPLT;
        ++(info_ptr->splt_palettes_num);
        ++np;
        ++entries;
     }
     while (--nentries);
  
     if (nentries > 0)
        png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
  }
  #endif /* sPLT */
  
  #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
  static png_byte
  check_location(png_const_structrp png_ptr, int location)
  {
     location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);
  
     /* New in 1.6.0; copy the location and check it.  This is an API
      * change; previously the app had to use the
      * png_set_unknown_chunk_location API below for each chunk.
      */
     if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
     {
        /* Write struct, so unknown chunks come from the app */
        png_app_warning(png_ptr,
            "png_set_unknown_chunks now expects a valid location");
        /* Use the old behavior */
        location = (png_byte)(png_ptr->mode &
            (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT));
     }
  
     /* This need not be an internal error - if the app calls
      * png_set_unknown_chunks on a read pointer it must get the location right.
      */
     if (location == 0)
        png_error(png_ptr, "invalid location in png_set_unknown_chunks");
  
     /* Now reduce the location to the top-most set bit by removing each least
      * significant bit in turn.
      */
     while (location != (location & -location))
        location &= ~(location & -location);
  
     /* The cast is safe because 'location' is a bit mask and only the low four
      * bits are significant.
      */
     return (png_byte)location;
  }
  
  void PNGAPI
  png_set_unknown_chunks(png_const_structrp png_ptr,
      png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
  {
     png_unknown_chunkp np;
  
     if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 ||
         unknowns == NULL)
        return;
  
     /* Check for the failure cases where support has been disabled at compile
      * time.  This code is hardly ever compiled - it's here because
      * STORE_UNKNOWN_CHUNKS is set by both read and write code (compiling in this
      * code) but may be meaningless if the read or write handling of unknown
      * chunks is not compiled in.
      */
  #  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
        defined(PNG_READ_SUPPORTED)
        if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
        {
           png_app_error(png_ptr, "no unknown chunk support on read");
  
           return;
        }
  #  endif
  #  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
        defined(PNG_WRITE_SUPPORTED)
        if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
        {
           png_app_error(png_ptr, "no unknown chunk support on write");
  
           return;
        }
  #  endif
  
     /* Prior to 1.6.0 this code used png_malloc_warn; however, this meant that
      * unknown critical chunks could be lost with just a warning resulting in
      * undefined behavior.  Now png_chunk_report is used to provide behavior
      * appropriate to read or write.
      */
     np = png_voidcast(png_unknown_chunkp, png_realloc_array(png_ptr,
         info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns,
         sizeof *np));
  
     if (np == NULL)
     {
        png_chunk_report(png_ptr, "too many unknown chunks",
            PNG_CHUNK_WRITE_ERROR);
  
        return;
     }
  
     png_free(png_ptr, info_ptr->unknown_chunks);
     info_ptr->unknown_chunks = np; /* safe because it is initialized */
     info_ptr->free_me |= PNG_FREE_UNKN;
  
     np += info_ptr->unknown_chunks_num;
  
     /* Increment unknown_chunks_num each time round the loop to protect the
      * just-allocated chunk data.
      */
     for (; num_unknowns > 0; --num_unknowns, ++unknowns)
     {
        memcpy(np->name, unknowns->name, (sizeof np->name));
        np->name[(sizeof np->name)-1] = '\0';
        np->location = check_location(png_ptr, unknowns->location);
  
        if (unknowns->size == 0)
        {
           np->data = NULL;
           np->size = 0;
        }
  
        else
        {
           np->data = png_voidcast(png_bytep,
               png_malloc_base(png_ptr, unknowns->size));
  
           if (np->data == NULL)
           {
              png_chunk_report(png_ptr, "unknown chunk: out of memory",
                  PNG_CHUNK_WRITE_ERROR);
              /* But just skip storing the unknown chunk */
              continue;
           }
  
           memcpy(np->data, unknowns->data, unknowns->size);
           np->size = unknowns->size;
        }
  
        /* These increments are skipped on out-of-memory for the data - the
         * unknown chunk entry gets overwritten if the png_chunk_report returns.
         * This is correct in the read case (the chunk is just dropped.)
         */
        ++np;
        ++(info_ptr->unknown_chunks_num);
     }
  }
  
  void PNGAPI
  png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
      int chunk, int location)
  {
     /* This API is pretty pointless in 1.6.0 because the location can be set
      * before the call to png_set_unknown_chunks.
      *
      * TODO: add a png_app_warning in 1.7
      */
     if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 &&
        chunk < info_ptr->unknown_chunks_num)
     {
        if ((location & (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT)) == 0)
        {
           png_app_error(png_ptr, "invalid unknown chunk location");
           /* Fake out the pre 1.6.0 behavior: */
           if (((unsigned int)location & PNG_HAVE_IDAT) != 0) /* undocumented! */
              location = PNG_AFTER_IDAT;
  
           else
              location = PNG_HAVE_IHDR; /* also undocumented */
        }
  
        info_ptr->unknown_chunks[chunk].location =
           check_location(png_ptr, location);
     }
  }
  #endif /* STORE_UNKNOWN_CHUNKS */
  
  #ifdef PNG_MNG_FEATURES_SUPPORTED
  png_uint_32 PNGAPI
  png_permit_mng_features (png_structrp png_ptr, png_uint_32 mng_features)
  {
     png_debug(1, "in png_permit_mng_features");
  
     if (png_ptr == NULL)
        return 0;
  
     png_ptr->mng_features_permitted = mng_features & PNG_ALL_MNG_FEATURES;
  
     return png_ptr->mng_features_permitted;
  }
  #endif
  
  #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
  static unsigned int
  add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
  {
     unsigned int i;
  
     /* Utility function: update the 'keep' state of a chunk if it is already in
      * the list, otherwise add it to the list.
      */
     for (i=0; i<count; ++i, list += 5)
     {
        if (memcmp(list, add, 4) == 0)
        {
           list[4] = (png_byte)keep;
  
           return count;
        }
     }
  
     if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
     {
        ++count;
        memcpy(list, add, 4);
        list[4] = (png_byte)keep;
     }
  
     return count;
  }
  
  void PNGAPI
  png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
      png_const_bytep chunk_list, int num_chunks_in)
  {
     png_bytep new_list;
     unsigned int num_chunks, old_num_chunks;
  
     if (png_ptr == NULL)
        return;
  
     if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST)
     {
        png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep");
  
        return;
     }
  
     if (num_chunks_in <= 0)
     {
        png_ptr->unknown_default = keep;
  
        /* '0' means just set the flags, so stop here */
        if (num_chunks_in == 0)
          return;
     }
  
     if (num_chunks_in < 0)
     {
        /* Ignore all unknown chunks and all chunks recognized by
         * libpng except for IHDR, PLTE, tRNS, IDAT, and IEND
         */
        static PNG_CONST png_byte chunks_to_ignore[] = {
           98,  75,  71,  68, '\0',  /* bKGD */
           99,  72,  82,  77, '\0',  /* cHRM */
          101,  88,  73, 102, '\0',  /* eXIf */
          103,  65,  77,  65, '\0',  /* gAMA */
          104,  73,  83,  84, '\0',  /* hIST */
          105,  67,  67,  80, '\0',  /* iCCP */
          105,  84,  88, 116, '\0',  /* iTXt */
          111,  70,  70, 115, '\0',  /* oFFs */
          112,  67,  65,  76, '\0',  /* pCAL */
          112,  72,  89, 115, '\0',  /* pHYs */
          115,  66,  73,  84, '\0',  /* sBIT */
          115,  67,  65,  76, '\0',  /* sCAL */
          115,  80,  76,  84, '\0',  /* sPLT */
          115,  84,  69,  82, '\0',  /* sTER */
          115,  82,  71,  66, '\0',  /* sRGB */
          116,  69,  88, 116, '\0',  /* tEXt */
          116,  73,  77,  69, '\0',  /* tIME */
          122,  84,  88, 116, '\0'   /* zTXt */
        };
  
        chunk_list = chunks_to_ignore;
        num_chunks = (unsigned int)/*SAFE*/(sizeof chunks_to_ignore)/5U;
     }
  
     else /* num_chunks_in > 0 */
     {
        if (chunk_list == NULL)
        {
           /* Prior to 1.6.0 this was silently ignored, now it is an app_error
            * which can be switched off.
            */
           png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list");
  
           return;
        }
  
        num_chunks = (unsigned int)num_chunks_in;
     }
  
     old_num_chunks = png_ptr->num_chunk_list;
     if (png_ptr->chunk_list == NULL)
        old_num_chunks = 0;
  
     /* Since num_chunks is always restricted to UINT_MAX/5 this can't overflow.
      */
     if (num_chunks + old_num_chunks > UINT_MAX/5)
     {
        png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks");
  
        return;
     }
  
     /* If these chunks are being reset to the default then no more memory is
      * required because add_one_chunk above doesn't extend the list if the 'keep'
      * parameter is the default.
      */
     if (keep != 0)
     {
        new_list = png_voidcast(png_bytep, png_malloc(png_ptr,
            5 * (num_chunks + old_num_chunks)));
  
        if (old_num_chunks > 0)
           memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks);
     }
  
     else if (old_num_chunks > 0)
        new_list = png_ptr->chunk_list;
  
     else
        new_list = NULL;
  
     /* Add the new chunks together with each one's handling code.  If the chunk
      * already exists the code is updated, otherwise the chunk is added to the
      * end.  (In libpng 1.6.0 order no longer matters because this code enforces
      * the earlier convention that the last setting is the one that is used.)
      */
     if (new_list != NULL)
     {
        png_const_bytep inlist;
        png_bytep outlist;
        unsigned int i;
  
        for (i=0; i<num_chunks; ++i)
        {
           old_num_chunks = add_one_chunk(new_list, old_num_chunks,
               chunk_list+5*i, keep);
        }
  
        /* Now remove any spurious 'default' entries. */
        num_chunks = 0;
        for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
        {
           if (inlist[4])
           {
              if (outlist != inlist)
                 memcpy(outlist, inlist, 5);
              outlist += 5;
              ++num_chunks;
           }
        }
  
        /* This means the application has removed all the specialized handling. */
        if (num_chunks == 0)
        {
           if (png_ptr->chunk_list != new_list)
              png_free(png_ptr, new_list);
  
           new_list = NULL;
        }
     }
  
     else
        num_chunks = 0;
  
     png_ptr->num_chunk_list = num_chunks;
  
     if (png_ptr->chunk_list != new_list)
     {
        if (png_ptr->chunk_list != NULL)
           png_free(png_ptr, png_ptr->chunk_list);
  
        png_ptr->chunk_list = new_list;
     }
  }
  #endif
  
  #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
  void PNGAPI
  png_set_read_user_chunk_fn(png_structrp png_ptr, png_voidp user_chunk_ptr,
      png_user_chunk_ptr read_user_chunk_fn)
  {
     png_debug(1, "in png_set_read_user_chunk_fn");
  
     if (png_ptr == NULL)
        return;
  
     png_ptr->read_user_chunk_fn = read_user_chunk_fn;
     png_ptr->user_chunk_ptr = user_chunk_ptr;
  }
  #endif
  
  #ifdef PNG_INFO_IMAGE_SUPPORTED
  void PNGAPI
  png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
      png_bytepp row_pointers)
  {
     png_debug1(1, "in %s storage function", "rows");
  
     if (png_ptr == NULL || info_ptr == NULL)
        return;
  
     if (info_ptr->row_pointers != NULL &&
         (info_ptr->row_pointers != row_pointers))
        png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
  
     info_ptr->row_pointers = row_pointers;
  
     if (row_pointers != NULL)
        info_ptr->valid |= PNG_INFO_IDAT;
  }
  #endif
  
  void PNGAPI
  png_set_compression_buffer_size(png_structrp png_ptr, size_t size)
  {
     if (png_ptr == NULL)
        return;
  
     if (size == 0 || size > PNG_UINT_31_MAX)
        png_error(png_ptr, "invalid compression buffer size");
  
  #  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
     if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
     {
        png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
        return;
     }
  #  endif
  
  #  ifdef PNG_WRITE_SUPPORTED
     if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
     {
        if (png_ptr->zowner != 0)
        {
           png_warning(png_ptr,
               "Compression buffer size cannot be changed because it is in use");
  
           return;
        }
  
  #ifndef __COVERITY__
        /* Some compilers complain that this is always false.  However, it
         * can be true when integer overflow happens.
         */
        if (size > ZLIB_IO_MAX)
        {
           png_warning(png_ptr,
               "Compression buffer size limited to system maximum");
           size = ZLIB_IO_MAX; /* must fit */
        }
  #endif
  
        if (size < 6)
        {
           /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
            * if this is permitted.
            */
           png_warning(png_ptr,
               "Compression buffer size cannot be reduced below 6");
  
           return;
        }
  
        if (png_ptr->zbuffer_size != size)
        {
           png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
           png_ptr->zbuffer_size = (uInt)size;
        }
     }
  #  endif
  }
  
  void PNGAPI
  png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
  {
     if (png_ptr != NULL && info_ptr != NULL)
        info_ptr->valid &= (unsigned int)(~mask);
  }
  
  
  #ifdef PNG_SET_USER_LIMITS_SUPPORTED
  /* This function was added to libpng 1.2.6 */
  void PNGAPI
  png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
      png_uint_32 user_height_max)
  {
     /* Images with dimensions larger than these limits will be
      * rejected by png_set_IHDR().  To accept any PNG datastream
      * regardless of dimensions, set both limits to 0x7fffffff.
      */
     if (png_ptr == NULL)
        return;
  
     png_ptr->user_width_max = user_width_max;
     png_ptr->user_height_max = user_height_max;
  }
  
  /* This function was added to libpng 1.4.0 */
  void PNGAPI
  png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
  {
     if (png_ptr != NULL)
        png_ptr->user_chunk_cache_max = user_chunk_cache_max;
  }
  
  /* This function was added to libpng 1.4.1 */
  void PNGAPI
  png_set_chunk_malloc_max (png_structrp png_ptr,
      png_alloc_size_t user_chunk_malloc_max)
  {
     if (png_ptr != NULL)
        png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
  }
  #endif /* ?SET_USER_LIMITS */
  
  
  #ifdef PNG_BENIGN_ERRORS_SUPPORTED
  void PNGAPI
  png_set_benign_errors(png_structrp png_ptr, int allowed)
  {
     png_debug(1, "in png_set_benign_errors");
  
     /* If allowed is 1, png_benign_error() is treated as a warning.
      *
      * If allowed is 0, png_benign_error() is treated as an error (which
      * is the default behavior if png_set_benign_errors() is not called).
      */
  
     if (allowed != 0)
        png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN |
           PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN;
  
     else
        png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN |
           PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN);
  }
  #endif /* BENIGN_ERRORS */
  
  #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
     /* Whether to report invalid palette index; added at libng-1.5.10.
      * It is possible for an indexed (color-type==3) PNG file to contain
      * pixels with invalid (out-of-range) indexes if the PLTE chunk has
      * fewer entries than the image's bit-depth would allow. We recover
      * from this gracefully by filling any incomplete palette with zeros
      * (opaque black).  By default, when this occurs libpng will issue
      * a benign error.  This API can be used to override that behavior.
      */
  void PNGAPI
  png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
  {
     png_debug(1, "in png_set_check_for_invalid_index");
  
     if (allowed > 0)
        png_ptr->num_palette_max = 0;
  
     else
        png_ptr->num_palette_max = -1;
  }
  #endif
  
  #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_pCAL_SUPPORTED) || \
      defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)
  /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
   * and if invalid, correct the keyword rather than discarding the entire
   * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in
   * length, forbids leading or trailing whitespace, multiple internal spaces,
   * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.
   *
   * The 'new_key' buffer must be 80 characters in size (for the keyword plus a
   * trailing '\0').  If this routine returns 0 then there was no keyword, or a
   * valid one could not be generated, and the caller must png_error.
   */
  png_uint_32 /* PRIVATE */
  png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
  {
  #ifdef PNG_WARNINGS_SUPPORTED
     png_const_charp orig_key = key;
  #endif
     png_uint_32 key_len = 0;
     int bad_character = 0;
     int space = 1;
  
     png_debug(1, "in png_check_keyword");
  
     if (key == NULL)
     {
        *new_key = 0;
        return 0;
     }
  
     while (*key && key_len < 79)
     {
        png_byte ch = (png_byte)*key++;
  
        if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
        {
           *new_key++ = ch; ++key_len; space = 0;
        }
  
        else if (space == 0)
        {
           /* A space or an invalid character when one wasn't seen immediately
            * before; output just a space.
            */
           *new_key++ = 32; ++key_len; space = 1;
  
           /* If the character was not a space then it is invalid. */
           if (ch != 32)
              bad_character = ch;
        }
  
        else if (bad_character == 0)
           bad_character = ch; /* just skip it, record the first error */
     }
  
     if (key_len > 0 && space != 0) /* trailing space */
     {
        --key_len; --new_key;
        if (bad_character == 0)
           bad_character = 32;
     }
  
     /* Terminate the keyword */
     *new_key = 0;
  
     if (key_len == 0)
        return 0;
  
  #ifdef PNG_WARNINGS_SUPPORTED
     /* Try to only output one warning per keyword: */
     if (*key != 0) /* keyword too long */
        png_warning(png_ptr, "keyword truncated");
  
     else if (bad_character != 0)
     {
        PNG_WARNING_PARAMETERS(p)
  
        png_warning_parameter(p, 1, orig_key);
        png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character);
  
        png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
     }
  #else /* !WARNINGS */
     PNG_UNUSED(png_ptr)
  #endif /* !WARNINGS */
  
     return key_len;
  }
  #endif /* TEXT || pCAL || iCCP || sPLT */
  #endif /* READ || WRITE */
  