    /* pngset.c - storage of image information into info struct
     *
     * Last changed in libpng 1.6.3 [July 18, 2013]
     * Copyright (c) 1998-2013 Glenn Randers-Pehrson
     * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
     * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
     *
     * This code is released under the libpng license.
     * For conditions of distribution and use, see the disclaimer
     * and license in png.h
     *
     * 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*/))
          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))
          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 Red X"),
          png_fixed(png_ptr, green_Y, "cHRM Red Y"),
          png_fixed(png_ptr, green_Z, "cHRM Red Z"),
          png_fixed(png_ptr, blue_X, "cHRM Red X"),
          png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
          png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
    }
    #  endif /* PNG_FLOATING_POINT_SUPPORTED */

    #endif /* PNG_cHRM_SUPPORTED */

    #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)
          info_ptr->channels = 3;

       else
          info_ptr->channels = 1;

       if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
          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)
    {
       png_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_error(png_ptr, "Invalid pCAL equation type");

       if (nparams < 0 || nparams > 255)
          png_error(png_ptr, "Invalid pCAL parameter count");

       /* Validate params[nparams] */
       for (i=0; i<nparams; ++i)
          if (params[i] == NULL ||
             !png_check_fp_string(params[i], strlen(params[i])))
             png_error(png_ptr, "Invalid format for pCAL parameter");

       info_ptr->pcal_purpose = png_voidcast(png_charp,
          png_malloc_warn(png_ptr, length));

       if (info_ptr->pcal_purpose == NULL)
       {
          png_warning(png_ptr, "Insufficient memory for pCAL purpose");
          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,
           (png_size_t)((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, (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)
    {
       png_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_debug1(1, "in %s storage function", "PLTE");

       if (png_ptr == NULL || info_ptr == NULL)
          return;

       if (num_palette < 0 || num_palette > PNG_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_chunk_report(png_ptr, "Invalid palette", PNG_CHUNK_ERROR);
          return;
       }

       /* 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 that has
        * 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, 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))
       {
          /* 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;
       png_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)
             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)
          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 ? "unexpected" :
          (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 /* PNG_iTXt_SUPPORTED */
          {
             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)
             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))
          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);

           /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
           png_ptr->trans_alpha = info_ptr->trans_alpha = png_voidcast(png_bytep,
             png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));

           if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
              memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
       }

       if (trans_color != NULL)
       {
          int sample_max = (1 << info_ptr->bit_depth);

          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");

          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
       {
          png_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 even 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);
             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,
             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;
       }
       while (++entries, --nentries);

       if (nentries > 0)
          png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
    }
    #endif /* PNG_sPLT_SUPPORTED */

    #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))
       {
          /* 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)
          {
             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))
          {
             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 ((location & PNG_HAVE_IDAT)) /* undocumented! */
                location = PNG_AFTER_IDAT;

             else
                location = PNG_HAVE_IHDR; /* also undocumented */
          }

          info_ptr->unknown_chunks[chunk].location =
             check_location(png_ptr, location);
       }
    }
    #endif

    #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 */
            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 = (sizeof chunks_to_ignore)/5;
       }

       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 = 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)
       {
          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 && (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)
          info_ptr->valid |= PNG_INFO_IDAT;
    }
    #endif

    void PNGAPI
    png_set_compression_buffer_size(png_structrp png_ptr, png_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)
          {
             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))
          {
             if (png_ptr->zowner != 0)
             {
                png_warning(png_ptr,
                  "Compression buffer size cannot be changed because it is in use");
                return;
             }

             if (size > ZLIB_IO_MAX)
             {
                png_warning(png_ptr,
                   "Compression buffer size limited to system maximum");
                size = ZLIB_IO_MAX; /* must fit */
             }

             else 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 && info_ptr)
          info_ptr->valid &= ~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 0x7ffffffL.
        */
       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)
           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)
          png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
    }
    #endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */

    #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)
          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 /* PNG_BENIGN_ERRORS_SUPPORTED */

    #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 zeroes
        * (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
    #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */