/* pngtest.c - a simple test program to test libpng

 *

 * Last changed in libpng 1.5.25 [December 3, 2015]

 * Copyright (c) 1998-2002,2004,2006-2015 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

 *

 * This program reads in a PNG image, writes it out again, and then

 * compares the two files.  If the files are identical, this shows that

 * the basic chunk handling, filtering, and (de)compression code is working

 * properly.  It does not currently test all of the transforms, although

 * it probably should.

 *

 * The program will report "FAIL" in certain legitimate cases:

 * 1) when the compression level or filter selection method is changed.

 * 2) when the maximum IDAT size (PNG_ZBUF_SIZE in pngconf.h) is not 8192.

 * 3) unknown unsafe-to-copy ancillary chunks or unknown critical chunks

 *    exist in the input file.

 * 4) others not listed here...

 * In these cases, it is best to check with another tool such as "pngcheck"

 * to see what the differences between the two files are.

 *

 * If a filename is given on the command-line, then this file is used

 * for the input, rather than the default "pngtest.png".  This allows

 * testing a wide variety of files easily.  You can also test a number

 * of files at once by typing "pngtest -m file1.png file2.png ..."

 */

#define _POSIX_SOURCE 1

#include <stdio.h></stdio.h>

#include <stdlib.h></stdlib.h>

#include <string.h></string.h>

/* Defined so I can write to a file on gui/windowing platforms */

/*  #define STDERR stderr  */

#define STDERR stdout   /* For DOS */

#include "png.h"

/* Known chunks that exist in pngtest.png must be supported or pngtest will fail

 * simply as a result of re-ordering them.  This may be fixed in 1.7

 *

 * pngtest allocates a single row buffer for each row and overwrites it,

 * therefore if the write side doesn't support the writing of interlaced images

 * nothing can be done for an interlaced image (and the code below will fail

 * horribly trying to write extra data after writing garbage).

 */

#if defined PNG_READ_SUPPORTED && /* else nothing can be done */\

   defined PNG_READ_bKGD_SUPPORTED &&\

   defined PNG_READ_cHRM_SUPPORTED &&\

   defined PNG_READ_gAMA_SUPPORTED &&\

   defined PNG_READ_oFFs_SUPPORTED &&\

   defined PNG_READ_pCAL_SUPPORTED &&\

   defined PNG_READ_pHYs_SUPPORTED &&\

   defined PNG_READ_sBIT_SUPPORTED &&\

   defined PNG_READ_sCAL_SUPPORTED &&\

   defined PNG_READ_sRGB_SUPPORTED &&\

   defined PNG_READ_sPLT_SUPPORTED &&\

   defined PNG_READ_tEXt_SUPPORTED &&\

   defined PNG_READ_tIME_SUPPORTED &&\

   defined PNG_READ_zTXt_SUPPORTED &&\

   (defined PNG_WRITE_INTERLACING_SUPPORTED || PNG_LIBPNG_VER >= 10700)

#ifdef PNG_ZLIB_HEADER

#  include PNG_ZLIB_HEADER /* defined by pnglibconf.h from 1.7 */

#else

#  include "zlib.h"

#endif

/* Copied from pngpriv.h but only used in error messages below. */

#ifndef PNG_ZBUF_SIZE

#  define PNG_ZBUF_SIZE 8192

#endif

#define FCLOSE(file) fclose(file)

#ifndef PNG_STDIO_SUPPORTED

typedef FILE                * png_FILE_p;

#endif

/* Makes pngtest verbose so we can find problems. */

#ifndef PNG_DEBUG

#  define PNG_DEBUG 0

#endif

#if PNG_DEBUG > 1

#  define pngtest_debug(m)        ((void)fprintf(stderr, m "\n"))

#  define pngtest_debug1(m,p1)    ((void)fprintf(stderr, m "\n", p1))

#  define pngtest_debug2(m,p1,p2) ((void)fprintf(stderr, m "\n", p1, p2))

#else

#  define pngtest_debug(m)        ((void)0)

#  define pngtest_debug1(m,p1)    ((void)0)

#  define pngtest_debug2(m,p1,p2) ((void)0)

#endif

#if !PNG_DEBUG

#  define SINGLE_ROWBUF_ALLOC  /* Makes buffer overruns easier to nail */

#endif

#ifndef PNG_UNUSED

#  define PNG_UNUSED(param) (void)param;

#endif

/* Turn on CPU timing

#define PNGTEST_TIMING

*/

#ifndef PNG_FLOATING_POINT_SUPPORTED

#undef PNGTEST_TIMING

#endif

#ifdef PNGTEST_TIMING

static float t_start, t_stop, t_decode, t_encode, t_misc;

#include <time.h></time.h>

#endif

#ifdef PNG_TIME_RFC1123_SUPPORTED

#define PNG_tIME_STRING_LENGTH 29

static int tIME_chunk_present = 0;

static char tIME_string[PNG_tIME_STRING_LENGTH] = "tIME chunk is not present";

#if PNG_LIBPNG_VER < 10619

#define png_convert_to_rfc1123_buffer(ts, t) tIME_to_str(read_ptr, ts, t)

static int

tIME_to_str(png_structp png_ptr, png_charp ts, png_const_timep t)

{

    png_const_charp str = png_convert_to_rfc1123(png_ptr, t);

    if (str == NULL)

        return 0;

    strcpy(ts, str);

    return 1;

}

#endif /* older libpng */

#endif

static int verbose = 0;

static int strict = 0;

static int relaxed = 0;

static int unsupported_chunks = 0; /* chunk unsupported by libpng in input */

static int error_count = 0; /* count calls to png_error */

static int warning_count = 0; /* count calls to png_warning */

/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */

#ifndef png_jmpbuf

#  define png_jmpbuf(png_ptr) png_ptr->jmpbuf

#endif

/* Defines for unknown chunk handling if required. */

#ifndef PNG_HANDLE_CHUNK_ALWAYS

#  define PNG_HANDLE_CHUNK_ALWAYS       3

#endif

#ifndef PNG_HANDLE_CHUNK_IF_SAFE

#  define PNG_HANDLE_CHUNK_IF_SAFE      2

#endif

/* Utility to save typing/errors, the argument must be a name */

#define MEMZERO(var) ((void)memset(&var, 0, sizeof var))

/* Example of using row callbacks to make a simple progress meter */

static int status_pass = 1;

static int status_dots_requested = 0;

static int status_dots = 1;

static void PNGCBAPI

read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)

{

   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX)

      return;

   if (status_pass != pass)

   {

      fprintf(stdout, "\n Pass %d: ", pass);

      status_pass = pass;

      status_dots = 31;

   }

   status_dots--;

   if (status_dots == 0)

   {

      fprintf(stdout, "\n         ");

      status_dots=30;

   }

   fprintf(stdout, "r");

}

#ifdef PNG_WRITE_SUPPORTED

static void PNGCBAPI

write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)

{

   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX || pass > 7)

      return;

   fprintf(stdout, "w");

}

#endif

#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED

/* Example of using a user transform callback (doesn't do anything at present).

 */

static void PNGCBAPI

read_user_callback(png_structp png_ptr, png_row_infop row_info, png_bytep data)

{

   PNG_UNUSED(png_ptr)

   PNG_UNUSED(row_info)

   PNG_UNUSED(data)

}

#endif

#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED

/* Example of using user transform callback (we don't transform anything,

 * but merely count the zero samples)

 */

static png_uint_32 zero_samples;

static void PNGCBAPI

count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)

{

   png_bytep dp = data;

   if (png_ptr == NULL)

      return;

   /* Contents of row_info:

    *  png_uint_32 width      width of row

    *  png_uint_32 rowbytes   number of bytes in row

    *  png_byte color_type    color type of pixels

    *  png_byte bit_depth     bit depth of samples

    *  png_byte channels      number of channels (1-4)

    *  png_byte pixel_depth   bits per pixel (depth*channels)

    */

    /* Counts the number of zero samples (or zero pixels if color_type is 3 */

    if (row_info->color_type == 0 || row_info->color_type == 3)

    {

       int pos = 0;

       png_uint_32 n, nstop;

       for (n = 0, nstop=row_info->width; n

       {

          if (row_info->bit_depth == 1)

          {

             if (((*dp << pos++ ) & 0x80) == 0)

                zero_samples++;

             if (pos == 8)

             {

                pos = 0;

                dp++;

             }

          }

          if (row_info->bit_depth == 2)

          {

             if (((*dp << (pos+=2)) & 0xc0) == 0)

                zero_samples++;

             if (pos == 8)

             {

                pos = 0;

                dp++;

             }

          }

          if (row_info->bit_depth == 4)

          {

             if (((*dp << (pos+=4)) & 0xf0) == 0)

                zero_samples++;

             if (pos == 8)

             {

                pos = 0;

                dp++;

             }

          }

          if (row_info->bit_depth == 8)

             if (*dp++ == 0)

                zero_samples++;

          if (row_info->bit_depth == 16)

          {

             if ((*dp | *(dp+1)) == 0)

                zero_samples++;

             dp+=2;

          }

       }

    }

    else /* Other color types */

    {

       png_uint_32 n, nstop;

       int channel;

       int color_channels = row_info->channels;

       if (row_info->color_type > 3)

          color_channels--;

       for (n = 0, nstop=row_info->width; n

       {

          for (channel = 0; channel < color_channels; channel++)

          {

             if (row_info->bit_depth == 8)

                if (*dp++ == 0)

                   zero_samples++;

             if (row_info->bit_depth == 16)

             {

                if ((*dp | *(dp+1)) == 0)

                   zero_samples++;

                dp+=2;

             }

          }

          if (row_info->color_type > 3)

          {

             dp++;

             if (row_info->bit_depth == 16)

                dp++;

          }

       }

    }

}

#endif /* WRITE_USER_TRANSFORM */

#ifndef PNG_STDIO_SUPPORTED

/* START of code to validate stdio-free compilation */

/* These copies of the default read/write functions come from pngrio.c and

 * pngwio.c.  They allow "don't include stdio" testing of the library.

 * This is the function that does the actual reading of data.  If you are

 * not reading from a standard C stream, you should create a replacement

 * read_data function and use it at run time with png_set_read_fn(), rather

 * than changing the library.

 */

#ifdef PNG_IO_STATE_SUPPORTED

void

pngtest_check_io_state(png_structp png_ptr, png_size_t data_length,

   png_uint_32 io_op);

void

pngtest_check_io_state(png_structp png_ptr, png_size_t data_length,

   png_uint_32 io_op)

{

   png_uint_32 io_state = png_get_io_state(png_ptr);

   int err = 0;

   /* Check if the current operation (reading / writing) is as expected. */

   if ((io_state & PNG_IO_MASK_OP) != io_op)

      png_error(png_ptr, "Incorrect operation in I/O state");

   /* Check if the buffer size specific to the current location

    * (file signature / header / data / crc) is as expected.

    */

   switch (io_state & PNG_IO_MASK_LOC)

   {

   case PNG_IO_SIGNATURE:

      if (data_length > 8)

         err = 1;

      break;

   case PNG_IO_CHUNK_HDR:

      if (data_length != 8)

         err = 1;

      break;

   case PNG_IO_CHUNK_DATA:

      break;  /* no restrictions here */

   case PNG_IO_CHUNK_CRC:

      if (data_length != 4)

         err = 1;

      break;

   default:

      err = 1;  /* uninitialized */

   }

   if (err != 0)

      png_error(png_ptr, "Bad I/O state or buffer size");

}

#endif

static void PNGCBAPI

pngtest_read_data(png_structp png_ptr, png_bytep data, png_size_t length)

{

   png_size_t check = 0;

   png_voidp io_ptr;

   /* fread() returns 0 on error, so it is OK to store this in a png_size_t

    * instead of an int, which is what fread() actually returns.

    */

   io_ptr = png_get_io_ptr(png_ptr);

   if (io_ptr != NULL)

   {

      check = fread(data, 1, length, (png_FILE_p)io_ptr);

   }

   if (check != length)

   {

      png_error(png_ptr, "Read Error");

   }

#ifdef PNG_IO_STATE_SUPPORTED

   pngtest_check_io_state(png_ptr, length, PNG_IO_READING);

#endif

}

#ifdef PNG_WRITE_FLUSH_SUPPORTED

static void PNGCBAPI

pngtest_flush(png_structp png_ptr)

{

   /* Do nothing; fflush() is said to be just a waste of energy. */

   PNG_UNUSED(png_ptr)   /* Stifle compiler warning */

}

#endif

/* This is the function that does the actual writing of data.  If you are

 * not writing to a standard C stream, you should create a replacement

 * write_data function and use it at run time with png_set_write_fn(), rather

 * than changing the library.

 */

static void PNGCBAPI

pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length)

{

   png_size_t check;

   check = fwrite(data, 1, length, (png_FILE_p)png_get_io_ptr(png_ptr));

   if (check != length)

   {

      png_error(png_ptr, "Write Error");

   }

#ifdef PNG_IO_STATE_SUPPORTED

   pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING);

#endif

}

#endif /* !STDIO */

/* This function is called when there is a warning, but the library thinks

 * it can continue anyway.  Replacement functions don't have to do anything

 * here if you don't want to.  In the default configuration, png_ptr is

 * not used, but it is passed in case it may be useful.

 */

typedef struct

{

   PNG_CONST char *file_name;

}  pngtest_error_parameters;

static void PNGCBAPI

pngtest_warning(png_structp png_ptr, png_const_charp message)

{

   PNG_CONST char *name = "UNKNOWN (ERROR!)";

   pngtest_error_parameters *test =

      (pngtest_error_parameters*)png_get_error_ptr(png_ptr);

   ++warning_count;

   if (test != NULL && test->file_name != NULL)

      name = test->file_name;

   fprintf(STDERR, "%s: libpng warning: %s\n", name, message);

}

/* This is the default error handling function.  Note that replacements for

 * this function MUST NOT RETURN, or the program will likely crash.  This

 * function is used by default, or if the program supplies NULL for the

 * error function pointer in png_set_error_fn().

 */

static void PNGCBAPI

pngtest_error(png_structp png_ptr, png_const_charp message)

{

   ++error_count;

   pngtest_warning(png_ptr, message);

   /* We can return because png_error calls the default handler, which is

    * actually OK in this case.

    */

}

/* END of code to validate stdio-free compilation */

/* START of code to validate memory allocation and deallocation */

#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG

/* Allocate memory.  For reasonable files, size should never exceed

 * 64K.  However, zlib may allocate more than 64K if you don't tell

 * it not to.  See zconf.h and png.h for more information.  zlib does

 * need to allocate exactly 64K, so whatever you call here must

 * have the ability to do that.

 *

 * This piece of code can be compiled to validate max 64K allocations

 * by setting MAXSEG_64K in zlib zconf.h *or* PNG_MAX_MALLOC_64K.

 */

typedef struct memory_information

{

   png_alloc_size_t          size;

   png_voidp                 pointer;

   struct memory_information *next;

} memory_information;

typedef memory_information *memory_infop;

static memory_infop pinformation = NULL;

static int current_allocation = 0;

static int maximum_allocation = 0;

static int total_allocation = 0;

static int num_allocations = 0;

png_voidp PNGCBAPI png_debug_malloc PNGARG((png_structp png_ptr,

    png_alloc_size_t size));

void PNGCBAPI png_debug_free PNGARG((png_structp png_ptr, png_voidp ptr));

png_voidp

PNGCBAPI png_debug_malloc(png_structp png_ptr, png_alloc_size_t size)

{

   /* png_malloc has already tested for NULL; png_create_struct calls

    * png_debug_malloc directly, with png_ptr == NULL which is OK

    */

   if (size == 0)

      return (NULL);

   /* This calls the library allocator twice, once to get the requested

      buffer and once to get a new free list entry. */

   {

      /* Disable malloc_fn and free_fn */

      memory_infop pinfo;

      png_set_mem_fn(png_ptr, NULL, NULL, NULL);

      pinfo = (memory_infop)png_malloc(png_ptr,

         (sizeof *pinfo));

      pinfo->size = size;

      current_allocation += size;

      total_allocation += size;

      num_allocations ++;

      if (current_allocation > maximum_allocation)

         maximum_allocation = current_allocation;

      pinfo->pointer = png_malloc(png_ptr, size);

      /* Restore malloc_fn and free_fn */

      png_set_mem_fn(png_ptr,

          NULL, png_debug_malloc, png_debug_free);

      if (size != 0 && pinfo->pointer == NULL)

      {

         current_allocation -= size;

         total_allocation -= size;

         png_error(png_ptr,

           "out of memory in pngtest->png_debug_malloc");

      }

      pinfo->next = pinformation;

      pinformation = pinfo;

      /* Make sure the caller isn't assuming zeroed memory. */

      memset(pinfo->pointer, 0xdd, pinfo->size);

      if (verbose != 0)

         printf("png_malloc %lu bytes at %p\n", (unsigned long)size,

            pinfo->pointer);

      return (png_voidp)(pinfo->pointer);

   }

}

/* Free a pointer.  It is removed from the list at the same time. */

void PNGCBAPI

png_debug_free(png_structp png_ptr, png_voidp ptr)

{

   if (png_ptr == NULL)

      fprintf(STDERR, "NULL pointer to png_debug_free.\n");

   if (ptr == 0)

   {

#if 0 /* This happens all the time. */

      fprintf(STDERR, "WARNING: freeing NULL pointer\n");

#endif

      return;

   }

   /* Unlink the element from the list. */

   if (pinformation != NULL)

   {

      memory_infop *ppinfo = &pinformation;

      for (;;)

      {

         memory_infop pinfo = *ppinfo;

         if (pinfo->pointer == ptr)

         {

            *ppinfo = pinfo->next;

            current_allocation -= pinfo->size;

            if (current_allocation < 0)

               fprintf(STDERR, "Duplicate free of memory\n");

            /* We must free the list element too, but first kill

               the memory that is to be freed. */

            memset(ptr, 0x55, pinfo->size);

            free(pinfo);

            pinfo = NULL;

            break;

         }

         if (pinfo->next == NULL)

         {

            fprintf(STDERR, "Pointer %p not found\n", ptr);

            break;

         }

         ppinfo = &pinfo->next;

      }

   }

   /* Finally free the data. */

   if (verbose != 0)

      printf("Freeing %p\n", ptr);

   if (ptr != NULL)

      free(ptr);

   ptr = NULL;

}

#endif /* USER_MEM && DEBUG */

/* END of code to test memory allocation/deallocation */

#ifdef PNG_READ_USER_CHUNKS_SUPPORTED

/* Demonstration of user chunk support of the sTER and vpAg chunks */

/* (sTER is a public chunk not yet known by libpng.  vpAg is a private

chunk used in ImageMagick to store "virtual page" size).  */

static struct user_chunk_data

{

   png_const_infop info_ptr;

   png_uint_32     vpAg_width, vpAg_height;

   png_byte        vpAg_units;

   png_byte        sTER_mode;

   int             location[2];

}

user_chunk_data;

/* Used for location and order; zero means nothing. */

#define have_sTER   0x01

#define have_vpAg   0x02

#define before_PLTE 0x10

#define before_IDAT 0x20

#define after_IDAT  0x40

static void

init_callback_info(png_const_infop info_ptr)

{

   MEMZERO(user_chunk_data);

   user_chunk_data.info_ptr = info_ptr;

}

static int

set_location(png_structp png_ptr, struct user_chunk_data *data, int what)

{

   int location;

   if ((data->location[0] & what) != 0 || (data->location[1] & what) != 0)

      return 0; /* already have one of these */

   /* Find where we are (the code below zeroes info_ptr to indicate that the

    * chunks before the first IDAT have been read.)

    */

   if (data->info_ptr == NULL) /* after IDAT */

      location = what | after_IDAT;

   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE) != 0)

      location = what | before_IDAT;

   else

      location = what | before_PLTE;

   if (data->location[0] == 0)

      data->location[0] = location;

   else

      data->location[1] = location;

   return 1; /* handled */

}

static int PNGCBAPI

read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)

{

   struct user_chunk_data *my_user_chunk_data =

      (struct user_chunk_data*)png_get_user_chunk_ptr(png_ptr);

   if (my_user_chunk_data == NULL)

      png_error(png_ptr, "lost user chunk pointer");

   /* Return one of the following:

    *    return (-n);  chunk had an error

    *    return (0);  did not recognize

    *    return (n);  success

    *

    * The unknown chunk structure contains the chunk data:

    * png_byte name[5];

    * png_byte *data;

    * png_size_t size;

    *

    * Note that libpng has already taken care of the CRC handling.

    */

   if (chunk->name[0] == 115 && chunk->name[1] ==  84 &&     /* s  T */

       chunk->name[2] ==  69 && chunk->name[3] ==  82)       /* E  R */

      {

         /* Found sTER chunk */

         if (chunk->size != 1)

            return (-1); /* Error return */

         if (chunk->data[0] != 0 && chunk->data[0] != 1)

            return (-1);  /* Invalid mode */

         if (set_location(png_ptr, my_user_chunk_data, have_sTER) != 0)

         {

            my_user_chunk_data->sTER_mode=chunk->data[0];

            return (1);

         }

         else

            return (0); /* duplicate sTER - give it to libpng */

      }

   if (chunk->name[0] != 118 || chunk->name[1] != 112 ||    /* v  p */

       chunk->name[2] !=  65 || chunk->name[3] != 103)      /* A  g */

      return (0); /* Did not recognize */

   /* Found ImageMagick vpAg chunk */

   if (chunk->size != 9)

      return (-1); /* Error return */

   if (set_location(png_ptr, my_user_chunk_data, have_vpAg) == 0)

      return (0);  /* duplicate vpAg */

   my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data);

   my_user_chunk_data->vpAg_height = png_get_uint_31(png_ptr, chunk->data + 4);

   my_user_chunk_data->vpAg_units = chunk->data[8];

   return (1);

}

#ifdef PNG_WRITE_SUPPORTED

static void

write_sTER_chunk(png_structp write_ptr)

{

   png_byte sTER[5] = {115,  84,  69,  82, '\0'};

   if (verbose != 0)

      fprintf(STDERR, "\n stereo mode = %d\n", user_chunk_data.sTER_mode);

   png_write_chunk(write_ptr, sTER, &user_chunk_data.sTER_mode, 1);

}

static void

write_vpAg_chunk(png_structp write_ptr)

{

   png_byte vpAg[5] = {118, 112,  65, 103, '\0'};

   png_byte vpag_chunk_data[9];

   if (verbose != 0)

      fprintf(STDERR, " vpAg = %lu x %lu, units = %d\n",

        (unsigned long)user_chunk_data.vpAg_width,

        (unsigned long)user_chunk_data.vpAg_height,

        user_chunk_data.vpAg_units);

   png_save_uint_32(vpag_chunk_data, user_chunk_data.vpAg_width);

   png_save_uint_32(vpag_chunk_data + 4, user_chunk_data.vpAg_height);

   vpag_chunk_data[8] = user_chunk_data.vpAg_units;

   png_write_chunk(write_ptr, vpAg, vpag_chunk_data, 9);

}

static void

write_chunks(png_structp write_ptr, int location)

{

   int i;

   /* Notice that this preserves the original chunk order, however chunks

    * intercepted by the callback will be written *after* chunks passed to

    * libpng.  This will actually reverse a pair of sTER chunks or a pair of

    * vpAg chunks, resulting in an error later.  This is not worth worrying

    * about - the chunks should not be duplicated!

    */

   for (i=0; i<2; ++i)

   {

      if (user_chunk_data.location[i] == (location | have_sTER))

         write_sTER_chunk(write_ptr);

      else if (user_chunk_data.location[i] == (location | have_vpAg))

         write_vpAg_chunk(write_ptr);

   }

}

#endif /* WRITE */

#else /* !READ_USER_CHUNKS */

#  define write_chunks(pp,loc) ((void)0)

#endif

/* END of code to demonstrate user chunk support */

/* START of code to check that libpng has the required text support; this only

 * checks for the write support because if read support is missing the chunk

 * will simply not be reported back to pngtest.

 */

#ifdef PNG_TEXT_SUPPORTED

static void

pngtest_check_text_support(png_structp png_ptr, png_textp text_ptr,

   int num_text)

{

   while (num_text > 0)

   {

      switch (text_ptr[--num_text].compression)

      {

         case PNG_TEXT_COMPRESSION_NONE:

            break;

         case PNG_TEXT_COMPRESSION_zTXt:

#           ifndef PNG_WRITE_zTXt_SUPPORTED

               ++unsupported_chunks;

               /* In libpng 1.7 this now does an app-error, so stop it: */

               text_ptr[num_text].compression = PNG_TEXT_COMPRESSION_NONE;

#           endif

            break;

         case PNG_ITXT_COMPRESSION_NONE:

         case PNG_ITXT_COMPRESSION_zTXt:

#           ifndef PNG_WRITE_iTXt_SUPPORTED

               ++unsupported_chunks;

               text_ptr[num_text].compression = PNG_TEXT_COMPRESSION_NONE;

#           endif

            break;

         default:

            /* This is an error */

            png_error(png_ptr, "invalid text chunk compression field");

            break;

      }

   }

}

#endif

/* END of code to check that libpng has the required text support */

/* Test one file */

static int

test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)

{

   static png_FILE_p fpin;

   static png_FILE_p fpout;  /* "static" prevents setjmp corruption */

   pngtest_error_parameters error_parameters;

   png_structp read_ptr;

   png_infop read_info_ptr, end_info_ptr;

#ifdef PNG_WRITE_SUPPORTED

   png_structp write_ptr;

   png_infop write_info_ptr;

   png_infop write_end_info_ptr;

#ifdef PNG_WRITE_FILTER_SUPPORTED

   int interlace_preserved = 1;

#endif /* WRITE_FILTER */

#else /* !WRITE */

   png_structp write_ptr = NULL;

   png_infop write_info_ptr = NULL;

   png_infop write_end_info_ptr = NULL;

#endif /* !WRITE */

   png_bytep row_buf;

   png_uint_32 y;

   png_uint_32 width, height;

   volatile int num_passes;

   int pass;

   int bit_depth, color_type;

   row_buf = NULL;

   error_parameters.file_name = inname;