/* pngrio.c - functions for data input
*
- * libpng 1.2.6 - August 15, 2004
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2004 Glenn Randers-Pehrson
+ * Last changed in libpng 1.5.0 [January 6, 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
+ *
* This file provides a location for all input. Users who need
* special handling are expected to write a function that has the same
* arguments as this and performs a similar function, but that possibly
* libpng use it at run time with png_set_read_fn(...).
*/
-#define PNG_INTERNAL
-#include "png.h"
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
/* Read the data from whatever input you are using. The default routine
- reads from a file pointer. Note that this routine sometimes gets called
- with very small lengths, so you should implement some kind of simple
- buffering if you are using unbuffered reads. This should never be asked
- to read more then 64K on a 16 bit machine. */
+ * reads from a file pointer. Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered reads. This should never be asked
+ * to read more then 64K on a 16 bit machine.
+ */
void /* PRIVATE */
png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
- png_debug1(4,"reading %d bytes\n", (int)length);
+ png_debug1(4, "reading %d bytes", (int)length);
+
if (png_ptr->read_data_fn != NULL)
(*(png_ptr->read_data_fn))(png_ptr, data, length);
+
else
png_error(png_ptr, "Call to NULL read function");
}
-#if !defined(PNG_NO_STDIO)
+#ifdef PNG_STDIO_SUPPORTED
/* 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. */
-#ifndef USE_FAR_KEYWORD
-void PNGAPI
+ * 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.
+ */
+# ifndef USE_FAR_KEYWORD
+void PNGCBAPI
png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
png_size_t check;
+ if (png_ptr == NULL)
+ return;
+
/* 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.
*/
-#if defined(_WIN32_WCE)
- if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
- check = 0;
-#else
- check = (png_size_t)fread(data, (png_size_t)1, length,
- (png_FILE_p)png_ptr->io_ptr);
-#endif
+ check = fread(data, 1, length, (png_FILE_p)png_ptr->io_ptr);
if (check != length)
png_error(png_ptr, "Read Error");
}
-#else
-/* this is the model-independent version. Since the standard I/O library
+# else
+/* This is the model-independent version. Since the standard I/O library
can't handle far buffers in the medium and small models, we have to copy
the data.
*/
#define NEAR_BUF_SIZE 1024
#define MIN(a,b) (a <= b ? a : b)
-static void /* PRIVATE */
+static void PNGCBAPI
png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
- int check;
+ png_size_t check;
png_byte *n_data;
png_FILE_p io_ptr;
+ if (png_ptr == NULL)
+ return;
+
/* Check if data really is near. If so, use usual code. */
n_data = (png_byte *)CVT_PTR_NOCHECK(data);
io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
+
if ((png_bytep)n_data == data)
{
-#if defined(_WIN32_WCE)
- if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
- check = 0;
-#else
check = fread(n_data, 1, length, io_ptr);
-#endif
}
+
else
{
png_byte buf[NEAR_BUF_SIZE];
png_size_t read, remaining, err;
check = 0;
remaining = length;
+
do
{
read = MIN(NEAR_BUF_SIZE, remaining);
-#if defined(_WIN32_WCE)
- if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
- err = 0;
-#else
- err = fread(buf, (png_size_t)1, read, io_ptr);
-#endif
+ err = fread(buf, 1, read, io_ptr);
png_memcpy(data, buf, read); /* copy far buffer to near buffer */
- if(err != read)
+
+ if (err != read)
break;
+
else
check += err;
+
data += read;
remaining -= read;
}
while (remaining != 0);
}
+
if ((png_uint_32)check != (png_uint_32)length)
png_error(png_ptr, "read Error");
}
-#endif
+# endif
#endif
/* This function allows the application to supply a new input function
- for libpng if standard C streams aren't being used.
-
- This function takes as its arguments:
- png_ptr - pointer to a png input data structure
- io_ptr - pointer to user supplied structure containing info about
- the input functions. May be NULL.
- read_data_fn - pointer to a new input function that takes as its
- arguments a pointer to a png_struct, a pointer to
- a location where input data can be stored, and a 32-bit
- unsigned int that is the number of bytes to be read.
- To exit and output any fatal error messages the new write
- function should call png_error(png_ptr, "Error msg"). */
+ * for libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ *
+ * png_ptr - pointer to a png input data structure
+ *
+ * io_ptr - pointer to user supplied structure containing info about
+ * the input functions. May be NULL.
+ *
+ * read_data_fn - pointer to a new input function that takes as its
+ * arguments a pointer to a png_struct, a pointer to
+ * a location where input data can be stored, and a 32-bit
+ * unsigned int that is the number of bytes to be read.
+ * To exit and output any fatal error messages the new write
+ * function should call png_error(png_ptr, "Error msg").
+ * May be NULL, in which case libpng's default function will
+ * be used.
+ */
void PNGAPI
png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
png_rw_ptr read_data_fn)
{
+ if (png_ptr == NULL)
+ return;
+
png_ptr->io_ptr = io_ptr;
-#if !defined(PNG_NO_STDIO)
+#ifdef PNG_STDIO_SUPPORTED
if (read_data_fn != NULL)
png_ptr->read_data_fn = read_data_fn;
+
else
png_ptr->read_data_fn = png_default_read_data;
#else
{
png_ptr->write_data_fn = NULL;
png_warning(png_ptr,
- "It's an error to set both read_data_fn and write_data_fn in the ");
- png_warning(png_ptr,
- "same structure. Resetting write_data_fn to NULL.");
+ "Can't set both read_data_fn and write_data_fn in the"
+ " same structure");
}
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
png_ptr->output_flush_fn = NULL;
#endif
}
+#endif /* PNG_READ_SUPPORTED */
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