LCOV - code coverage report
Current view: directory - media/libpng - pngrio.c (source / functions) Found Hit Coverage
Test: app.info Lines: 21 12 57.1 %
Date: 2012-06-02 Functions: 3 2 66.7 %

       1                 : 
       2                 : /* pngrio.c - functions for data input
       3                 :  *
       4                 :  * Last changed in libpng 1.5.0 [January 6, 2011]
       5                 :  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
       6                 :  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
       7                 :  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
       8                 :  *
       9                 :  * This code is released under the libpng license.
      10                 :  * For conditions of distribution and use, see the disclaimer
      11                 :  * and license in png.h
      12                 :  *
      13                 :  * This file provides a location for all input.  Users who need
      14                 :  * special handling are expected to write a function that has the same
      15                 :  * arguments as this and performs a similar function, but that possibly
      16                 :  * has a different input method.  Note that you shouldn't change this
      17                 :  * function, but rather write a replacement function and then make
      18                 :  * libpng use it at run time with png_set_read_fn(...).
      19                 :  */
      20                 : 
      21                 : #include "pngpriv.h"
      22                 : 
      23                 : #ifdef PNG_READ_SUPPORTED
      24                 : 
      25                 : /* Read the data from whatever input you are using.  The default routine
      26                 :  * reads from a file pointer.  Note that this routine sometimes gets called
      27                 :  * with very small lengths, so you should implement some kind of simple
      28                 :  * buffering if you are using unbuffered reads.  This should never be asked
      29                 :  * to read more then 64K on a 16 bit machine.
      30                 :  */
      31                 : void /* PRIVATE */
      32              37 : png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
      33                 : {
      34                 :    png_debug1(4, "reading %d bytes", (int)length);
      35                 : 
      36              37 :    if (png_ptr->read_data_fn != NULL)
      37              37 :       (*(png_ptr->read_data_fn))(png_ptr, data, length);
      38                 : 
      39                 :    else
      40               0 :       png_error(png_ptr, "Call to NULL read function");
      41              37 : }
      42                 : 
      43                 : #ifdef PNG_STDIO_SUPPORTED
      44                 : /* This is the function that does the actual reading of data.  If you are
      45                 :  * not reading from a standard C stream, you should create a replacement
      46                 :  * read_data function and use it at run time with png_set_read_fn(), rather
      47                 :  * than changing the library.
      48                 :  */
      49                 : #  ifndef USE_FAR_KEYWORD
      50                 : void PNGCBAPI
      51               0 : png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
      52                 : {
      53                 :    png_size_t check;
      54                 : 
      55               0 :    if (png_ptr == NULL)
      56               0 :       return;
      57                 : 
      58                 :    /* fread() returns 0 on error, so it is OK to store this in a png_size_t
      59                 :     * instead of an int, which is what fread() actually returns.
      60                 :     */
      61               0 :    check = fread(data, 1, length, (png_FILE_p)png_ptr->io_ptr);
      62                 : 
      63               0 :    if (check != length)
      64               0 :       png_error(png_ptr, "Read Error");
      65                 : }
      66                 : #  else
      67                 : /* This is the model-independent version. Since the standard I/O library
      68                 :    can't handle far buffers in the medium and small models, we have to copy
      69                 :    the data.
      70                 : */
      71                 : 
      72                 : #define NEAR_BUF_SIZE 1024
      73                 : #define MIN(a,b) (a <= b ? a : b)
      74                 : 
      75                 : static void PNGCBAPI
      76                 : png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
      77                 : {
      78                 :    png_size_t check;
      79                 :    png_byte *n_data;
      80                 :    png_FILE_p io_ptr;
      81                 : 
      82                 :    if (png_ptr == NULL)
      83                 :       return;
      84                 : 
      85                 :    /* Check if data really is near. If so, use usual code. */
      86                 :    n_data = (png_byte *)CVT_PTR_NOCHECK(data);
      87                 :    io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
      88                 : 
      89                 :    if ((png_bytep)n_data == data)
      90                 :    {
      91                 :       check = fread(n_data, 1, length, io_ptr);
      92                 :    }
      93                 : 
      94                 :    else
      95                 :    {
      96                 :       png_byte buf[NEAR_BUF_SIZE];
      97                 :       png_size_t read, remaining, err;
      98                 :       check = 0;
      99                 :       remaining = length;
     100                 : 
     101                 :       do
     102                 :       {
     103                 :          read = MIN(NEAR_BUF_SIZE, remaining);
     104                 :          err = fread(buf, 1, read, io_ptr);
     105                 :          png_memcpy(data, buf, read); /* copy far buffer to near buffer */
     106                 : 
     107                 :          if (err != read)
     108                 :             break;
     109                 : 
     110                 :          else
     111                 :             check += err;
     112                 : 
     113                 :          data += read;
     114                 :          remaining -= read;
     115                 :       }
     116                 :       while (remaining != 0);
     117                 :    }
     118                 : 
     119                 :    if ((png_uint_32)check != (png_uint_32)length)
     120                 :       png_error(png_ptr, "read Error");
     121                 : }
     122                 : #  endif
     123                 : #endif
     124                 : 
     125                 : /* This function allows the application to supply a new input function
     126                 :  * for libpng if standard C streams aren't being used.
     127                 :  *
     128                 :  * This function takes as its arguments:
     129                 :  *
     130                 :  * png_ptr      - pointer to a png input data structure
     131                 :  *
     132                 :  * io_ptr       - pointer to user supplied structure containing info about
     133                 :  *                the input functions.  May be NULL.
     134                 :  *
     135                 :  * read_data_fn - pointer to a new input function that takes as its
     136                 :  *                arguments a pointer to a png_struct, a pointer to
     137                 :  *                a location where input data can be stored, and a 32-bit
     138                 :  *                unsigned int that is the number of bytes to be read.
     139                 :  *                To exit and output any fatal error messages the new write
     140                 :  *                function should call png_error(png_ptr, "Error msg").
     141                 :  *                May be NULL, in which case libpng's default function will
     142                 :  *                be used.
     143                 :  */
     144                 : void PNGAPI
     145               8 : png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
     146                 :    png_rw_ptr read_data_fn)
     147                 : {
     148               8 :    if (png_ptr == NULL)
     149               0 :       return;
     150                 : 
     151               8 :    png_ptr->io_ptr = io_ptr;
     152                 : 
     153                 : #ifdef PNG_STDIO_SUPPORTED
     154               8 :    if (read_data_fn != NULL)
     155               4 :       png_ptr->read_data_fn = read_data_fn;
     156                 : 
     157                 :    else
     158               4 :       png_ptr->read_data_fn = png_default_read_data;
     159                 : #else
     160                 :    png_ptr->read_data_fn = read_data_fn;
     161                 : #endif
     162                 : 
     163                 :    /* It is an error to write to a read device */
     164               8 :    if (png_ptr->write_data_fn != NULL)
     165                 :    {
     166               0 :       png_ptr->write_data_fn = NULL;
     167                 :       png_warning(png_ptr,
     168                 :           "Can't set both read_data_fn and write_data_fn in the"
     169                 :           " same structure");
     170                 :    }
     171                 : 
     172                 : #ifdef PNG_WRITE_FLUSH_SUPPORTED
     173               8 :    png_ptr->output_flush_fn = NULL;
     174                 : #endif
     175                 : }
     176                 : #endif /* PNG_READ_SUPPORTED */

Generated by: LCOV version 1.7