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 *

 * Last changed in libpng 1.5.1 [February 3, 2011]

 * Copyright (c) 1998-2011 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

 */

typedef png_libpng_version_1_5_1 Your_png_h_is_not_version_1_5_1;

 * of the PNG file signature.  If the PNG data is embedded into another

 * stream we can set num_bytes = 8 so that libpng will not attempt to read

 * or write any of the magic bytes before it starts on the IHDR.

 */

void PNGAPI

png_set_sig_bytes(png_structp png_ptr, int num_bytes)

{

   png_debug(1, "in png_set_sig_bytes");

      return;

      png_error(png_ptr, "Too many bytes for PNG signature");

}

 * checking less than the full 8-byte signature so that those apps that

 * already read the first few bytes of a file to determine the file type

 * can simply check the remaining bytes for extra assurance.  Returns

 * an integer less than, equal to, or greater than zero if sig is found,

 * respectively, to be less than, to match, or be greater than the correct

 * PNG signature (this is the same behaviour as strcmp, memcmp, etc).

 */

int PNGAPI

png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)

{

   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};

      num_to_check = 8;

      return (-1);

      return (-1);

      num_to_check = 8 - start;

}

/* Function to allocate memory for zlib */

PNG_FUNCTION(voidpf /* PRIVATE */,

png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)

{

   png_voidp ptr;

   png_structp p=(png_structp)png_ptr;

   png_uint_32 save_flags=p->flags;

   png_alloc_size_t num_bytes;

      return (NULL);

   {

     png_warning (p, "Potential overflow in png_zalloc()");

     return (NULL);

   }

   num_bytes = (png_alloc_size_t)items * size;

   ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);

   p->flags=save_flags;

}

void /* PRIVATE */

png_zfree(voidpf png_ptr, voidpf ptr)

{

   png_free((png_structp)png_ptr, (png_voidp)ptr);

}

 * in case CRC is > 32 bits to leave the top bits 0.

 */

void /* PRIVATE */

png_reset_crc(png_structp png_ptr)

{

   png_ptr->crc = crc32(0, Z_NULL, 0);

}

 * much data to this routine as the largest single buffer size.  We

 * also check that this data will actually be used before going to the

 * trouble of calculating it.

 */

void /* PRIVATE */

png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length)

{

   int need_crc = 1;

   {

      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==

          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))

         need_crc = 0;

   }

   {

      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)

         need_crc = 0;

   }

      png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);

}

 * really need the png_ptr, but it could potentially be useful in the

 * future.  This should be used in favour of malloc(png_sizeof(png_info))

 * and png_info_init() so that applications that want to use a shared

 * libpng don't have to be recompiled if png_info changes size.

 */

PNG_FUNCTION(png_infop,PNGAPI

png_create_info_struct,(png_structp png_ptr),PNG_ALLOCATED)

{

   png_infop info_ptr;

      return (NULL);

   info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,

      png_ptr->malloc_fn, png_ptr->mem_ptr);

#else

   info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);

#endif

   if (info_ptr != NULL)

      png_info_init_3(&info_ptr, png_sizeof(png_info));

}

 * Normally, one would use either png_destroy_read_struct() or

 * png_destroy_write_struct() to free an info struct, but this may be

 * useful for some applications.

 */

void PNGAPI

png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)

{

   png_infop info_ptr = NULL;

      return;

      info_ptr = *info_ptr_ptr;

   {

      png_info_destroy(png_ptr, info_ptr);

      png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,

          png_ptr->mem_ptr);

#else

      png_destroy_struct((png_voidp)info_ptr);

#endif

      *info_ptr_ptr = NULL;

   }

}

 * and applications using it are urged to use png_create_info_struct()

 * instead.

 */

png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)

{

   png_infop info_ptr = *ptr_ptr;

      return;

   {

      png_destroy_struct(info_ptr);

      info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);

      *ptr_ptr = info_ptr;

   }

   png_memset(info_ptr, 0, png_sizeof(png_info));

}

png_data_freer(png_structp png_ptr, png_infop info_ptr,

   int freer, png_uint_32 mask)

{

   png_debug(1, "in png_data_freer");

      return;

      info_ptr->free_me |= mask;

      info_ptr->free_me &= ~mask;

      png_warning(png_ptr,

         "Unknown freer parameter in png_data_freer");

}

png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,

   int num)

{

   png_debug(1, "in png_free_data");

      return;

   /* Free text item num or (if num == -1) all text items */

   if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)

   {

      if (num != -1)

      {

         if (info_ptr->text && info_ptr->text[num].key)

         {

            png_free(png_ptr, info_ptr->text[num].key);

            info_ptr->text[num].key = NULL;

         }

      }

      {

         int i;

         for (i = 0; i < info_ptr->num_text; i++)

             png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);

         png_free(png_ptr, info_ptr->text);

         info_ptr->text = NULL;

         info_ptr->num_text=0;

      }

   }

#endif

   /* Free any tRNS entry */

   if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)

   {

      png_free(png_ptr, info_ptr->trans_alpha);

      info_ptr->trans_alpha = NULL;

      info_ptr->valid &= ~PNG_INFO_tRNS;

   }

#endif

   /* Free any sCAL entry */

   if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)

   {

#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)

      png_free(png_ptr, info_ptr->scal_s_width);

      png_free(png_ptr, info_ptr->scal_s_height);

      info_ptr->scal_s_width = NULL;

      info_ptr->scal_s_height = NULL;

#endif

      info_ptr->valid &= ~PNG_INFO_sCAL;

   }

#endif

   /* Free any pCAL entry */

   if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)

   {

      png_free(png_ptr, info_ptr->pcal_purpose);

      png_free(png_ptr, info_ptr->pcal_units);

      info_ptr->pcal_purpose = NULL;

      info_ptr->pcal_units = NULL;

      if (info_ptr->pcal_params != NULL)

         {

            int i;

            for (i = 0; i < (int)info_ptr->pcal_nparams; i++)

            {

               png_free(png_ptr, info_ptr->pcal_params[i]);

               info_ptr->pcal_params[i] = NULL;

            }

            png_free(png_ptr, info_ptr->pcal_params);

            info_ptr->pcal_params = NULL;

         }

      info_ptr->valid &= ~PNG_INFO_pCAL;

   }

#endif

   /* Free any iCCP entry */

   if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)

   {

      png_free(png_ptr, info_ptr->iccp_name);

      png_free(png_ptr, info_ptr->iccp_profile);

      info_ptr->iccp_name = NULL;

      info_ptr->iccp_profile = NULL;

      info_ptr->valid &= ~PNG_INFO_iCCP;

   }

#endif

   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */

   if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)

   {

      if (num != -1)

      {

         if (info_ptr->splt_palettes)

         {

            png_free(png_ptr, info_ptr->splt_palettes[num].name);

            png_free(png_ptr, info_ptr->splt_palettes[num].entries);

            info_ptr->splt_palettes[num].name = NULL;

            info_ptr->splt_palettes[num].entries = NULL;

         }

      }

      {

         if (info_ptr->splt_palettes_num)

         {

            int i;

            for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)

               png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);

            info_ptr->splt_palettes = NULL;

            info_ptr->splt_palettes_num = 0;

         }

         info_ptr->valid &= ~PNG_INFO_sPLT;

      }

   }

#endif

   if (png_ptr->unknown_chunk.data)

   {

      png_free(png_ptr, png_ptr->unknown_chunk.data);

      png_ptr->unknown_chunk.data = NULL;

   }

   {

      if (num != -1)

      {

          if (info_ptr->unknown_chunks)

          {

             png_free(png_ptr, info_ptr->unknown_chunks[num].data);

             info_ptr->unknown_chunks[num].data = NULL;

          }

      }

      {

         int i;

         {

            for (i = 0; i < info_ptr->unknown_chunks_num; i++)

               png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);

            info_ptr->unknown_chunks = NULL;

            info_ptr->unknown_chunks_num = 0;

         }

      }

   }

#endif

   /* Free any hIST entry */

   if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)

   {

      png_free(png_ptr, info_ptr->hist);

      info_ptr->hist = NULL;

      info_ptr->valid &= ~PNG_INFO_hIST;

   }

#endif

   if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)

   {

      png_zfree(png_ptr, info_ptr->palette);

      info_ptr->palette = NULL;

      info_ptr->valid &= ~PNG_INFO_PLTE;

      info_ptr->num_palette = 0;

   }

   /* Free any image bits attached to the info structure */

   if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)

   {

      if (info_ptr->row_pointers)

      {

         int row;

         for (row = 0; row < (int)info_ptr->height; row++)

         {

            png_free(png_ptr, info_ptr->row_pointers[row]);

            info_ptr->row_pointers[row] = NULL;

         }

         png_free(png_ptr, info_ptr->row_pointers);

         info_ptr->row_pointers = NULL;

      }

      info_ptr->valid &= ~PNG_INFO_IDAT;

   }

#endif

      mask &= ~PNG_FREE_MUL;

}

 * pointing to before re-using it or freeing the struct itself.  Recall

 * that png_free() checks for NULL pointers for us.

 */

void /* PRIVATE */

png_info_destroy(png_structp png_ptr, png_infop info_ptr)

{

   png_debug(1, "in png_info_destroy");

   if (png_ptr->num_chunk_list)

   {

      png_free(png_ptr, png_ptr->chunk_list);

      png_ptr->chunk_list = NULL;

      png_ptr->num_chunk_list = 0;

   }

#endif

}

#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */

 * functions.  The application should free any memory associated with this

 * pointer before png_write_destroy() or png_read_destroy() are called.

 */

png_voidp PNGAPI

png_get_io_ptr(png_structp png_ptr)

{

   if (png_ptr == NULL)

      return (NULL);

}

#  ifdef PNG_STDIO_SUPPORTED

/* Initialize the default input/output functions for the PNG file.  If you

 * use your own read or write routines, you can call either png_set_read_fn()

 * or png_set_write_fn() instead of png_init_io().  If you have defined

 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't

 * necessarily available.

 */

void PNGAPI

png_init_io(png_structp png_ptr, png_FILE_p fp)

{

   png_debug(1, "in png_init_io");

      return;

}

#  endif

/* Convert the supplied time into an RFC 1123 string suitable for use in

 * a "Creation Time" or other text-based time string.

 */

png_const_charp PNGAPI

png_convert_to_rfc1123(png_structp png_ptr, png_const_timep ptime)

{

   static PNG_CONST char short_months[12][4] =

        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",

         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

      return (NULL);

   {

      png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*

         png_sizeof(char)));

   }

   {

      char near_time_buf[29];

      png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000",

          ptime->day % 32, short_months[(ptime->month - 1) % 12],

          ptime->year, ptime->hour % 24, ptime->minute % 60,

          ptime->second % 61);

      png_memcpy(png_ptr->time_buffer, near_time_buf,

          29*png_sizeof(char));

   }

#    else

   png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000",

       ptime->day % 32, short_months[(ptime->month - 1) % 12],

       ptime->year, ptime->hour % 24, ptime->minute % 60,

       ptime->second % 61);

#    endif

   return png_ptr->time_buffer;

}

#  endif /* PNG_TIME_RFC1123_SUPPORTED */

png_get_copyright(png_const_structp png_ptr)

{

   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */

#ifdef PNG_STRING_COPYRIGHT

   return PNG_STRING_COPYRIGHT

#else

#  ifdef __STDC__

   return PNG_STRING_NEWLINE \

     "libpng version 1.5.1 - February 3, 2011" PNG_STRING_NEWLINE \

     "Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \

     "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \

     "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \

     PNG_STRING_NEWLINE;

#  else

      return "libpng version 1.5.1 - February 3, 2011\

      Copyright (c) 1998-2011 Glenn Randers-Pehrson\

      Copyright (c) 1996-1997 Andreas Dilger\

      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";

#  endif

#endif

}

 * format 1.0.0 through 99.99.99zz.  To get the version of *.h files

 * used with your application, print out PNG_LIBPNG_VER_STRING, which

 * is defined in png.h.

 * Note: now there is no difference between png_get_libpng_ver() and

 * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,

 * it is guaranteed that png.c uses the correct version of png.h.

 */

png_const_charp PNGAPI

png_get_libpng_ver(png_const_structp png_ptr)

{

   /* Version of *.c files used when building libpng */

   return png_get_header_ver(png_ptr);

}

png_get_header_ver(png_const_structp png_ptr)

{

   /* Version of *.h files used when building libpng */

   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */

   return PNG_LIBPNG_VER_STRING;

}

png_get_header_version(png_const_structp png_ptr)

{

   /* Returns longer string containing both version and date */

   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */

#ifdef __STDC__

   return PNG_HEADER_VERSION_STRING

#  ifndef PNG_READ_SUPPORTED

   "     (NO READ SUPPORT)"

#  endif

   PNG_STRING_NEWLINE;

#else

   return PNG_HEADER_VERSION_STRING;

#endif

}

#  ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED

int PNGAPI

png_handle_as_unknown(png_structp png_ptr, png_const_bytep chunk_name)

{

   /* Check chunk_name and return "keep" value if it's on the list, else 0 */

   int i;

   png_bytep p;

   if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0)

      return 0;

   for (i = png_ptr->num_chunk_list; i; i--, p -= 5)

      if (!png_memcmp(chunk_name, p, 4))

        return ((int)*(p + 4));

   return 0;

}

#  endif

#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */

/* This function, added to libpng-1.0.6g, is untested. */

int PNGAPI

png_reset_zstream(png_structp png_ptr)

{

   if (png_ptr == NULL)

      return Z_STREAM_ERROR;

}

#endif /* PNG_READ_SUPPORTED */

png_uint_32 PNGAPI

png_access_version_number(void)

{

   /* Version of *.c files used when building libpng */

   return((png_uint_32)PNG_LIBPNG_VER);

}

#  ifdef PNG_SIZE_T

/* Added at libpng version 1.2.6 */

   PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));

png_size_t PNGAPI

png_convert_size(size_t size)

{

   if (size > (png_size_t)-1)

      PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */

}

#  endif /* PNG_SIZE_T */

#  ifdef PNG_CHECK_cHRM_SUPPORTED

png_check_cHRM_fixed(png_structp png_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)

{

   int ret = 1;

   unsigned long xy_hi,xy_lo,yx_hi,yx_lo;

      return 0;

         red_x < 0 ||   red_y <  0 ||

       green_x < 0 || green_y <  0 ||

        blue_x < 0 ||  blue_y <  0)

   {

      png_warning(png_ptr,

        "Ignoring attempt to set negative chromaticity value");

      ret = 0;

   }

   if (white_x > (png_fixed_point)PNG_UINT_31_MAX ||

       white_y > (png_fixed_point)PNG_UINT_31_MAX ||

         red_x > (png_fixed_point)PNG_UINT_31_MAX ||

         red_y > (png_fixed_point)PNG_UINT_31_MAX ||

       green_x > (png_fixed_point)PNG_UINT_31_MAX ||

       green_y > (png_fixed_point)PNG_UINT_31_MAX ||

        blue_x > (png_fixed_point)PNG_UINT_31_MAX ||

        blue_y > (png_fixed_point)PNG_UINT_31_MAX )

   {

      png_warning(png_ptr,

        "Ignoring attempt to set chromaticity value exceeding 21474.83");

      ret = 0;

   }

   if (white_x > 100000L - white_y)

   {

      png_warning(png_ptr, "Invalid cHRM white point");

      ret = 0;

   }

   {

      png_warning(png_ptr, "Invalid cHRM red point");

      ret = 0;

   }

   {

      png_warning(png_ptr, "Invalid cHRM green point");

      ret = 0;

   }

   {

      png_warning(png_ptr, "Invalid cHRM blue point");

      ret = 0;

   }

   png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo);

   {

      png_warning(png_ptr,

         "Ignoring attempt to set cHRM RGB triangle with zero area");

      ret = 0;

   }

}

#  endif /* PNG_CHECK_cHRM_SUPPORTED */

png_check_IHDR(png_structp png_ptr,

   png_uint_32 width, png_uint_32 height, int bit_depth,

   int color_type, int interlace_type, int compression_type,

   int filter_type)

{

   int error = 0;

   if (width == 0)

   {

      png_warning(png_ptr, "Image width is zero in IHDR");

      error = 1;

   }

   {

      png_warning(png_ptr, "Image height is zero in IHDR");

      error = 1;

   }

   if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX)

   if (width > PNG_USER_WIDTH_MAX)

#  endif

   {

      png_warning(png_ptr, "Image width exceeds user limit in IHDR");

      error = 1;

   }

   if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX)

#  else

   if (height > PNG_USER_HEIGHT_MAX)

#  endif

   {

      png_warning(png_ptr, "Image height exceeds user limit in IHDR");

      error = 1;

   }

   {

      png_warning(png_ptr, "Invalid image width in IHDR");

      error = 1;

   }

   {

      png_warning(png_ptr, "Invalid image height in IHDR");

      error = 1;

   }

                 >> 3)      /* 8-byte RGBA pixels */

                 - 48       /* bigrowbuf hack */

                 - 1        /* filter byte */

                 - 7*8      /* rounding of width to multiple of 8 pixels */

                 - 8)       /* extra max_pixel_depth pad */

      png_warning(png_ptr, "Width is too large for libpng to process pixels");

   if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&

       bit_depth != 8 && bit_depth != 16)

   {

      png_warning(png_ptr, "Invalid bit depth in IHDR");

      error = 1;

   }

       color_type == 5 || color_type > 6)

   {

      png_warning(png_ptr, "Invalid color type in IHDR");

      error = 1;

   }

       ((color_type == PNG_COLOR_TYPE_RGB ||

         color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||

         color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))

   {

      png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");

      error = 1;

   }

   {

      png_warning(png_ptr, "Unknown interlace method in IHDR");

      error = 1;

   }

   {

      png_warning(png_ptr, "Unknown compression method in IHDR");

      error = 1;

   }

   /* Accept filter_method 64 (intrapixel differencing) only if

    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and

    * 2. Libpng did not read a PNG signature (this filter_method is only

    *    used in PNG datastreams that are embedded in MNG datastreams) and

    * 3. The application called png_permit_mng_features with a mask that

    *    included PNG_FLAG_MNG_FILTER_64 and

    * 4. The filter_method is 64 and

    * 5. The color_type is RGB or RGBA

    */

   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) &&

       png_ptr->mng_features_permitted)

      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");

   {

      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&

          (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&

          ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&

          (color_type == PNG_COLOR_TYPE_RGB ||

          color_type == PNG_COLOR_TYPE_RGB_ALPHA)))

      {

         png_warning(png_ptr, "Unknown filter method in IHDR");

         error = 1;

      }

      {

         png_warning(png_ptr, "Invalid filter method in IHDR");

         error = 1;

      }

   }

   if (filter_type != PNG_FILTER_TYPE_BASE)

   {

      png_warning(png_ptr, "Unknown filter method in IHDR");

      error = 1;

   }

#  endif

      png_error(png_ptr, "Invalid IHDR data");

}

/* ASCII to fp functions */

/* Check an ASCII formated floating point value, see the more detailed

 * comments in pngpriv.h

 */

/* The following is used internally to preserve the 'valid' flag */

#define png_fp_add(state, flags) ((state) |= (flags))

#define png_fp_set(state, value)\

   ((state) = (value) | ((state) & PNG_FP_WAS_VALID))

#define PNG_FP_SIGN   0  /* [+-] */

#define PNG_FP_DOT    4  /* . */

#define PNG_FP_DIGIT  8  /* [0123456789] */

#define PNG_FP_E     12  /* [Ee] */

png_check_fp_number(png_const_charp string, png_size_t size, int *statep,

   png_size_tp whereami)

{

   int state = *statep;

   png_size_t i = *whereami;

   {

      int type;

      /* First find the type of the next character */

      {

         char ch = string[i];

            type = PNG_FP_DIGIT;

         {

         case 43: case 45:  type = PNG_FP_SIGN;  break;

         case 46:           type = PNG_FP_DOT;   break;

         case 69: case 101: type = PNG_FP_E;     break;

         default:           goto PNG_FP_End;

         }

      }

       * state, the type is arranged to not overlap the

       * bits of the PNG_FP_STATE.

       */

      switch ((state & PNG_FP_STATE) + type)

      {

      case PNG_FP_INTEGER + PNG_FP_SIGN:

         if (state & PNG_FP_SAW_ANY)

            goto PNG_FP_End; /* not a part of the number */

         break;

         /* Ok as trailer, ok as lead of fraction. */

         if (state & PNG_FP_SAW_DOT) /* two dots */

            goto PNG_FP_End;

            png_fp_add(state, PNG_FP_SAW_DOT);

            png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);

         if (state & PNG_FP_SAW_DOT) /* delayed fraction */

            png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);

      case PNG_FP_INTEGER + PNG_FP_E:

         if ((state & PNG_FP_SAW_DIGIT) == 0)

            goto PNG_FP_End;

         goto PNG_FP_End; ** no sign in exponent */

         goto PNG_FP_End; ** Because SAW_DOT is always set */

         png_fp_add(state, PNG_FP_SAW_DIGIT + PNG_FP_WAS_VALID);

         break;

         /* This is correct because the trailing '.' on an

          * integer is handled above - so we can only get here

          * with the sequence ".E" (with no preceding digits).

          */

         if ((state & PNG_FP_SAW_DIGIT) == 0)

            goto PNG_FP_End;

         if (state & PNG_FP_SAW_ANY)

            goto PNG_FP_End; /* not a part of the number */

         goto PNG_FP_End; */

         png_fp_add(state, PNG_FP_SAW_DIGIT + PNG_FP_WAS_VALID);

         goto PNG_FP_End; */

      }

      ++i;

   }

   /* Here at the end, update the state and return the correct

    * return code.

    */

   *statep = state;

   *whereami = i;

}

int

png_check_fp_string(png_const_charp string, png_size_t size)

{

   int        state=0;

   png_size_t char_index=0;

      (char_index == size || string[char_index] == 0);

}

#endif /* pCAL or sCAL */

#  ifdef PNG_FLOATING_POINT_SUPPORTED

/* Utility used below - a simple accurate power of ten from an integral

 * exponent.

 */

static double

png_pow10(int power)

{

   int recip = 0;

   double d = 1;

    * 10 is exact whereas .1 is inexact in base 2

    */

   if (power < 0)

   {

      if (power < DBL_MIN_10_EXP) return 0;

      recip = 1, power = -power;

   }

   {

      /* Decompose power bitwise. */

      double mult = 10;

      do

      {

         if (power & 1) d *= mult;

         mult *= mult;

         power >>= 1;

      }

      while (power > 0);

   }

   /* else power is 0 and d is 1 */

}

 * precision.

 */

void /* PRIVATE */

png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,

    double fp, unsigned int precision)

{

   /* We use standard functions from math.h, but not printf because

    * that would require stdio.  The caller must supply a buffer of

    * sufficient size or we will png_error.  The tests on size and

    * the space in ascii[] consumed are indicated below.

    */

   if (precision < 1)

      precision = DBL_DIG;

   if (precision > DBL_DIG+1)

      precision = DBL_DIG+1;

   if (size >= precision+5) /* See the requirements below. */

   {

      if (fp < 0)

      {

         fp = -fp;

         *ascii++ = 45; /* '-'  PLUS 1 TOTAL 1*/

         --size;

      }

      {

         int exp_b10;       /* A base 10 exponent */

         double base;   /* 10^exp_b10 */

          * the calculation below rounds down when converting

          * from base 2 to base 10 (multiply by log10(2) -

          * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to

          * be increased.  Note that the arithmetic shift

          * performs a floor() unlike C arithmetic - using a

          * C multiply would break the following for negative

          * exponents.

          */

         (void)frexp(fp, &exp_b10); /* exponent to base 2 */

         base = png_pow10(exp_b10); /* May underflow */