1 

     2 /* pngerror.c - stub functions for i/o and memory allocation

     3  *

     4  * Last changed in libpng 1.2.30 [August 15, 2008]

     5  * For conditions of distribution and use, see copyright notice in png.h

     6  * Copyright (c) 1998-2008 Glenn Randers-Pehrson

     7  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

     8  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

     9  *

    10  * This file provides a location for all error handling.  Users who

    11  * need special error handling are expected to write replacement functions

    12  * and use png_set_error_fn() to use those functions.  See the instructions

    13  * at each function.

    14  */

    15 

    16 #define PNG_INTERNAL

    17 #include "png.h"

    18 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)

    19 

    20 static void /* PRIVATE */

    21 png_default_error PNGARG((png_structp png_ptr,

    22   png_const_charp error_message));

    23 #ifndef PNG_NO_WARNINGS

    24 static void /* PRIVATE */

    25 png_default_warning PNGARG((png_structp png_ptr,

    26   png_const_charp warning_message));

    27 #endif /* PNG_NO_WARNINGS */

    28 

    29 /* This function is called whenever there is a fatal error.  This function

    30  * should not be changed.  If there is a need to handle errors differently,

    31  * you should supply a replacement error function and use png_set_error_fn()

    32  * to replace the error function at run-time.

    33  */

    34 #ifndef PNG_NO_ERROR_TEXT

    35 void PNGAPI

    36 png_error(png_structp png_ptr, png_const_charp error_message)

    37 {

    38 #ifdef PNG_ERROR_NUMBERS_SUPPORTED

    39    char msg[16];

    40    if (png_ptr != NULL)

    41    {

    42      if (png_ptr->flags&

    43        (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))

    44      {

    45        if (*error_message == '#')

    46        {

    47          /* Strip "#nnnn " from beginning of error message. */

    48            int offset;

    49            for (offset = 1; offset<15; offset++)

    50               if (error_message[offset] == ' ')

    51                   break;

    52            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)

    53            {

    54               int i;

    55               for (i = 0; i < offset - 1; i++)

    56                  msg[i] = error_message[i + 1];

    57               msg[i - 1] = '\0';

    58               error_message = msg;

    59            }

    60            else

    61               error_message += offset;

    62        }

    63        else

    64        {

    65            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)

    66            {

    67               msg[0] = '0';

    68               msg[1] = '\0';

    69               error_message = msg;

    70            }

    71        }

    72      }

    73    }

    74 #endif

    75    if (png_ptr != NULL && png_ptr->error_fn != NULL)

    76       (*(png_ptr->error_fn))(png_ptr, error_message);

    77 

    78    /* If the custom handler doesn't exist, or if it returns,

    79       use the default handler, which will not return. */

    80    png_default_error(png_ptr, error_message);

    81 }

    82 #else

    83 void PNGAPI

    84 png_err(png_structp png_ptr)

    85 {

    86    if (png_ptr != NULL && png_ptr->error_fn != NULL)

    87       (*(png_ptr->error_fn))(png_ptr, '\0');

    88 

    89    /* If the custom handler doesn't exist, or if it returns,

    90       use the default handler, which will not return. */

    91    png_default_error(png_ptr, '\0');

    92 }

    93 #endif /* PNG_NO_ERROR_TEXT */

    94 

    95 #ifndef PNG_NO_WARNINGS

    96 /* This function is called whenever there is a non-fatal error.  This function

    97  * should not be changed.  If there is a need to handle warnings differently,

    98  * you should supply a replacement warning function and use

    99  * png_set_error_fn() to replace the warning function at run-time.

   100  */

   101 void PNGAPI

   102 png_warning(png_structp png_ptr, png_const_charp warning_message)

   103 {

   104    int offset = 0;

   105    if (png_ptr != NULL)

   106    {

   107 #ifdef PNG_ERROR_NUMBERS_SUPPORTED

   108    if (png_ptr->flags&

   109      (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))

   110 #endif

   111      {

   112        if (*warning_message == '#')

   113        {

   114            for (offset = 1; offset < 15; offset++)

   115               if (warning_message[offset] == ' ')

   116                   break;

   117        }

   118      }

   119      if (png_ptr != NULL && png_ptr->warning_fn != NULL)

   120         (*(png_ptr->warning_fn))(png_ptr, warning_message + offset);

   121    }

   122    else

   123       png_default_warning(png_ptr, warning_message + offset);

   124 }

   125 #endif /* PNG_NO_WARNINGS */

   126 

   127 

   128 /* These utilities are used internally to build an error message that relates

   129  * to the current chunk.  The chunk name comes from png_ptr->chunk_name,

   130  * this is used to prefix the message.  The message is limited in length

   131  * to 63 bytes, the name characters are output as hex digits wrapped in []

   132  * if the character is invalid.

   133  */

   134 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))

   135 static PNG_CONST char png_digit[16] = {

   136    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',

   137    'A', 'B', 'C', 'D', 'E', 'F'

   138 };

   139 

   140 #define PNG_MAX_ERROR_TEXT 64

   141 

   142 #if !defined(PNG_NO_WARNINGS) || !defined(PNG_NO_ERROR_TEXT)

   143 static void /* PRIVATE */

   144 png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp

   145    error_message)

   146 {

   147    int iout = 0, iin = 0;

   148 

   149    while (iin < 4)

   150    {

   151       int c = png_ptr->chunk_name[iin++];

   152       if (isnonalpha(c))

   153       {

   154          buffer[iout++] = '[';

   155          buffer[iout++] = png_digit[(c & 0xf0) >> 4];

   156          buffer[iout++] = png_digit[c & 0x0f];

   157          buffer[iout++] = ']';

   158       }

   159       else

   160       {

   161          buffer[iout++] = (png_byte)c;

   162       }

   163    }

   164 

   165    if (error_message == NULL)

   166       buffer[iout] = '\0';

   167    else

   168    {

   169       buffer[iout++] = ':';

   170       buffer[iout++] = ' ';

   171       png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);

   172       buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';

   173    }

   174 }

   175 

   176 #ifdef PNG_READ_SUPPORTED

   177 void PNGAPI

   178 png_chunk_error(png_structp png_ptr, png_const_charp error_message)

   179 {

   180    char msg[18+PNG_MAX_ERROR_TEXT];

   181    if (png_ptr == NULL)

   182      png_error(png_ptr, error_message);

   183    else

   184    {

   185      png_format_buffer(png_ptr, msg, error_message);

   186      png_error(png_ptr, msg);

   187    }

   188 }

   189 #endif /* PNG_READ_SUPPORTED */

   190 #endif /* !defined(PNG_NO_WARNINGS) || !defined(PNG_NO_ERROR_TEXT) */

   191 

   192 #ifndef PNG_NO_WARNINGS

   193 void PNGAPI

   194 png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)

   195 {

   196    char msg[18+PNG_MAX_ERROR_TEXT];

   197    if (png_ptr == NULL)

   198      png_warning(png_ptr, warning_message);

   199    else

   200    {

   201      png_format_buffer(png_ptr, msg, warning_message);

   202      png_warning(png_ptr, msg);

   203    }

   204 }

   205 #endif /* PNG_NO_WARNINGS */

   206 

   207 

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

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

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

   211  * error function pointer in png_set_error_fn().

   212  */

   213 static void /* PRIVATE */

   214 png_default_error(png_structp png_ptr, png_const_charp error_message)

   215 {

   216 #ifndef PNG_NO_CONSOLE_IO

   217 #ifdef PNG_ERROR_NUMBERS_SUPPORTED

   218    if (*error_message == '#')

   219    {

   220      /* Strip "#nnnn " from beginning of warning message. */

   221      int offset;

   222      char error_number[16];

   223      for (offset = 0; offset<15; offset++)

   224      {

   225          error_number[offset] = error_message[offset + 1];

   226          if (error_message[offset] == ' ')

   227              break;

   228      }

   229      if ((offset > 1) && (offset < 15))

   230      {

   231        error_number[offset - 1] = '\0';

   232        fprintf(stderr, "libpng error no. %s: %s\n", error_number,

   233           error_message + offset + 1);

   234      }

   235      else

   236        fprintf(stderr, "libpng error: %s, offset=%d\n", error_message, offset);

   237    }

   238    else

   239 #endif

   240    fprintf(stderr, "libpng error: %s\n", error_message);

   241 #endif

   242 

   243 #ifdef PNG_SETJMP_SUPPORTED

   244    if (png_ptr)

   245    {

   246 #  ifdef USE_FAR_KEYWORD

   247    {

   248       jmp_buf jmpbuf;

   249       png_memcpy(jmpbuf, png_ptr->jmpbuf, png_sizeof(jmp_buf));

   250       longjmp(jmpbuf, 1);

   251    }

   252 #  else

   253    longjmp(png_ptr->jmpbuf, 1);

   254 #  endif

   255    }

   256 #else

   257    PNG_ABORT();

   258 #endif

   259 #ifdef PNG_NO_CONSOLE_IO

   260    error_message = error_message; /* make compiler happy */

   261 #endif

   262 }

   263 

   264 #ifndef PNG_NO_WARNINGS

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

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

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

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

   269  */

   270 static void /* PRIVATE */

   271 png_default_warning(png_structp png_ptr, png_const_charp warning_message)

   272 {

   273 #ifndef PNG_NO_CONSOLE_IO

   274 #  ifdef PNG_ERROR_NUMBERS_SUPPORTED

   275    if (*warning_message == '#')

   276    {

   277      int offset;

   278      char warning_number[16];

   279      for (offset = 0; offset < 15; offset++)

   280      {

   281         warning_number[offset] = warning_message[offset + 1];

   282         if (warning_message[offset] == ' ')

   283             break;

   284      }

   285      if ((offset > 1) && (offset < 15))

   286      {

   287        warning_number[offset + 1] = '\0';

   288        fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,

   289           warning_message + offset);

   290      }

   291      else

   292        fprintf(stderr, "libpng warning: %s\n", warning_message);

   293    }

   294    else

   295 #  endif

   296      fprintf(stderr, "libpng warning: %s\n", warning_message);

   297 #else

   298    warning_message = warning_message; /* make compiler happy */

   299 #endif

   300    png_ptr = png_ptr; /* make compiler happy */

   301 }

   302 #endif /* PNG_NO_WARNINGS */

   303 

   304 /* This function is called when the application wants to use another method

   305  * of handling errors and warnings.  Note that the error function MUST NOT

   306  * return to the calling routine or serious problems will occur.  The return

   307  * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)

   308  */

   309 void PNGAPI

   310 png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,

   311    png_error_ptr error_fn, png_error_ptr warning_fn)

   312 {

   313    if (png_ptr == NULL)

   314       return;

   315    png_ptr->error_ptr = error_ptr;

   316    png_ptr->error_fn = error_fn;

   317    png_ptr->warning_fn = warning_fn;

   318 }

   319 

   320 

   321 /* This function returns a pointer to the error_ptr associated with the user

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

   323  * pointer before png_write_destroy and png_read_destroy are called.

   324  */

   325 png_voidp PNGAPI

   326 png_get_error_ptr(png_structp png_ptr)

   327 {

   328    if (png_ptr == NULL)

   329       return NULL;

   330    return ((png_voidp)png_ptr->error_ptr);

   331 }

   332 

   333 

   334 #ifdef PNG_ERROR_NUMBERS_SUPPORTED

   335 void PNGAPI

   336 png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)

   337 {

   338    if (png_ptr != NULL)

   339    {

   340      png_ptr->flags &=

   341        ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);

   342    }

   343 }

   344 #endif

   345 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */