guard against nullptr

[wxWidgets.git] / src / png / pngwio.c

diff --git a/src/png/pngwio.c b/src/png/pngwio.c
index f0dc1e2d5a434a48c3e3b9d63b76febce52a55a8..513a71a06222ad42cb0e1e9513c550c37cbc5dd4 100644 (file)
--- a/src/png/pngwio.c
+++ b/src/png/pngwio.c
@@ -1,12 +1,15 @@
 
 /* pngwio.c - functions for data output
  *
 
 /* pngwio.c - functions for data output
  *

- * 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 1.4.0 [January 3, 2010]
+ * Copyright (c) 1998-2010 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.)
  *
  * (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 output.  Users who need
  * special handling are expected to write functions that have the same
  * arguments as these and perform similar functions, but that possibly
  * This file provides a location for all output.  Users who need
  * special handling are expected to write functions that have the same
  * arguments as these and perform similar functions, but that possibly


@@ -15,15 +18,17 @@
  * them at run time with png_set_write_fn(...).
  */
 
  * them at run time with png_set_write_fn(...).
  */
 

-#define PNG_INTERNAL
+#define PNG_NO_PEDANTIC_WARNINGS

 #include "png.h"
 #ifdef PNG_WRITE_SUPPORTED
 #include "png.h"
 #ifdef PNG_WRITE_SUPPORTED

+#include "pngpriv.h"

 
 /* Write the data to whatever output you are using.  The default routine
 
 /* Write the data to whatever output you are using.  The default routine

-   writes to 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 writes.  This should never be asked
-   to write more than 64K on a 16 bit machine.  */
+ * writes to 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 writes.  This should never be asked
+ * to write more than 64K on a 16 bit machine.
+ */

 
 void /* PRIVATE */
 png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 
 void /* PRIVATE */
 png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)


@@ -34,31 +39,29 @@ png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
       png_error(png_ptr, "Call to NULL write function");
 }
 
       png_error(png_ptr, "Call to NULL write function");
 }
 

-#if !defined(PNG_NO_STDIO)
+#ifdef PNG_STDIO_SUPPORTED

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

 #ifndef USE_FAR_KEYWORD
 void PNGAPI
 png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_uint_32 check;
 
 #ifndef USE_FAR_KEYWORD
 void PNGAPI
 png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_uint_32 check;
 

-#if defined(_WIN32_WCE)
-   if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
-      check = 0;
-#else
+   if (png_ptr == NULL)
+      return;

    check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
    check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));

-#endif

    if (check != length)
       png_error(png_ptr, "Write Error");
 }
 #else
    if (check != length)
       png_error(png_ptr, "Write Error");
 }
 #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.
-*/
+/* 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)
 
 #define NEAR_BUF_SIZE 1024
 #define MIN(a,b) (a <= b ? a : b)


@@ -70,17 +73,14 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
    png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
    png_FILE_p io_ptr;
 
    png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
    png_FILE_p io_ptr;
 

+   if (png_ptr == NULL)
+      return;

    /* Check if data really is near. If so, use usual code. */
    near_data = (png_byte *)CVT_PTR_NOCHECK(data);
    io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
    if ((png_bytep)near_data == data)
    {
    /* Check if data really is near. If so, use usual code. */
    near_data = (png_byte *)CVT_PTR_NOCHECK(data);
    io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
    if ((png_bytep)near_data == data)
    {

-#if defined(_WIN32_WCE)
-      if ( !WriteFile(io_ptr, near_data, length, &check, NULL) )
-         check = 0;
-#else

       check = fwrite(near_data, 1, length, io_ptr);
       check = fwrite(near_data, 1, length, io_ptr);

-#endif

    }
    else
    {
    }
    else
    {


@@ -91,17 +91,14 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
       do
       {
          written = MIN(NEAR_BUF_SIZE, remaining);
       do
       {
          written = MIN(NEAR_BUF_SIZE, remaining);

-         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
-#if defined(_WIN32_WCE)
-         if ( !WriteFile(io_ptr, buf, written, &err, NULL) )
-            err = 0;
-#else
+         png_memcpy(buf, data, written); /* Copy far buffer to near buffer */

          err = fwrite(buf, 1, written, io_ptr);
          err = fwrite(buf, 1, written, io_ptr);

-#endif

          if (err != written)
             break;
          if (err != written)
             break;

+

          else
             check += err;
          else
             check += err;

+

          data += written;
          remaining -= written;
       }
          data += written;
          remaining -= written;
       }


@@ -115,9 +112,10 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 #endif
 
 /* This function is called to output any data pending writing (normally
 #endif
 
 /* This function is called to output any data pending writing (normally

-   to disk).  After png_flush is called, there should be no data pending
-   writing in any buffers. */
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+ * to disk).  After png_flush is called, there should be no data pending
+ * writing in any buffers.
+ */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED

 void /* PRIVATE */
 png_flush(png_structp png_ptr)
 {
 void /* PRIVATE */
 png_flush(png_structp png_ptr)
 {


@@ -125,61 +123,72 @@ png_flush(png_structp png_ptr)
       (*(png_ptr->output_flush_fn))(png_ptr);
 }
 
       (*(png_ptr->output_flush_fn))(png_ptr);
 }
 

-#if !defined(PNG_NO_STDIO)
+#ifdef PNG_STDIO_SUPPORTED

 void PNGAPI
 png_default_flush(png_structp png_ptr)
 {
 void PNGAPI
 png_default_flush(png_structp png_ptr)
 {

-#if !defined(_WIN32_WCE)

    png_FILE_p io_ptr;
    png_FILE_p io_ptr;

+   if (png_ptr == NULL)
+      return;

    io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
    io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));

-   if (io_ptr != NULL)
-      fflush(io_ptr);
-#endif
+   fflush(io_ptr);

 }
 #endif
 #endif
 
 /* This function allows the application to supply new output functions for
 }
 #endif
 #endif
 
 /* This function allows the application to supply new output functions for

-   libpng if standard C streams aren't being used.
-
-   This function takes as its arguments:
-   png_ptr       - pointer to a png output data structure
-   io_ptr        - pointer to user supplied structure containing info about
-                   the output functions.  May be NULL.
-   write_data_fn - pointer to a new output function that takes as its
-                   arguments a pointer to a png_struct, a pointer to
-                   data to be written, and a 32-bit unsigned int that is
-                   the number of bytes to be written.  The new write
-                   function should call png_error(png_ptr, "Error msg")
-                   to exit and output any fatal error messages.
-   flush_data_fn - pointer to a new flush function that takes as its
-                   arguments a pointer to a png_struct.  After a call to
-                   the flush function, there should be no data in any buffers
-                   or pending transmission.  If the output method doesn't do
-                   any buffering of ouput, a function prototype must still be
-                   supplied although it doesn't have to do anything.  If
-                   PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
-                   time, output_flush_fn will be ignored, although it must be
-                   supplied for compatibility. */
+ * libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ * png_ptr       - pointer to a png output data structure
+ * io_ptr        - pointer to user supplied structure containing info about
+ *                 the output functions.  May be NULL.
+ * write_data_fn - pointer to a new output function that takes as its
+ *                 arguments a pointer to a png_struct, a pointer to
+ *                 data to be written, and a 32-bit unsigned int that is
+ *                 the number of bytes to be written.  The new write
+ *                 function should call png_error(png_ptr, "Error msg")
+ *                 to exit and output any fatal error messages.  May be
+ *                 NULL, in which case libpng's default function will
+ *                 be used.
+ * flush_data_fn - pointer to a new flush function that takes as its
+ *                 arguments a pointer to a png_struct.  After a call to
+ *                 the flush function, there should be no data in any buffers
+ *                 or pending transmission.  If the output method doesn't do
+ *                 any buffering of output, a function prototype must still be
+ *                 supplied although it doesn't have to do anything.  If
+ *                 PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
+ *                 time, output_flush_fn will be ignored, although it must be
+ *                 supplied for compatibility.  May be NULL, in which case
+ *                 libpng's default function will be used, if
+ *                 PNG_WRITE_FLUSH_SUPPORTED is defined.  This is not
+ *                 a good idea if io_ptr does not point to a standard
+ *                 *FILE structure.
+ */

 void PNGAPI
 png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
 {
 void PNGAPI
 png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
 {

+   if (png_ptr == NULL)
+      return;
+

    png_ptr->io_ptr = io_ptr;
 
    png_ptr->io_ptr = io_ptr;
 

-#if !defined(PNG_NO_STDIO)
+#ifdef PNG_STDIO_SUPPORTED

    if (write_data_fn != NULL)
       png_ptr->write_data_fn = write_data_fn;
    if (write_data_fn != NULL)
       png_ptr->write_data_fn = write_data_fn;

+

    else
       png_ptr->write_data_fn = png_default_write_data;
 #else
    png_ptr->write_data_fn = write_data_fn;
 #endif
 
    else
       png_ptr->write_data_fn = png_default_write_data;
 #else
    png_ptr->write_data_fn = write_data_fn;
 #endif
 

-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
-#if !defined(PNG_NO_STDIO)
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#ifdef PNG_STDIO_SUPPORTED

    if (output_flush_fn != NULL)
       png_ptr->output_flush_fn = output_flush_fn;
    if (output_flush_fn != NULL)
       png_ptr->output_flush_fn = output_flush_fn;

+

    else
       png_ptr->output_flush_fn = png_default_flush;
 #else
    else
       png_ptr->output_flush_fn = png_default_flush;
 #else


@@ -194,33 +203,37 @@ png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
       png_warning(png_ptr,
          "Attempted to set both read_data_fn and write_data_fn in");
       png_warning(png_ptr,
       png_warning(png_ptr,
          "Attempted to set both read_data_fn and write_data_fn in");
       png_warning(png_ptr,

-         "the same structure.  Resetting read_data_fn to NULL.");
+         "the same structure.  Resetting read_data_fn to NULL");

    }
 }
 
    }
 }
 

-#if defined(USE_FAR_KEYWORD)
-#if defined(_MSC_VER)
-void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
+#ifdef USE_FAR_KEYWORD
+#ifdef _MSC_VER
+void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)

 {
    void *near_ptr;
    void FAR *far_ptr;
    FP_OFF(near_ptr) = FP_OFF(ptr);
    far_ptr = (void FAR *)near_ptr;
 {
    void *near_ptr;
    void FAR *far_ptr;
    FP_OFF(near_ptr) = FP_OFF(ptr);
    far_ptr = (void FAR *)near_ptr;

-   if(check != 0)
-      if(FP_SEG(ptr) != FP_SEG(far_ptr))
-         png_error(png_ptr,"segment lost in conversion");
+
+   if (check != 0)
+      if (FP_SEG(ptr) != FP_SEG(far_ptr))
+         png_error(png_ptr, "segment lost in conversion");
+

    return(near_ptr);
 }
 #  else
    return(near_ptr);
 }
 #  else

-void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
+void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)

 {
    void *near_ptr;
    void FAR *far_ptr;
    near_ptr = (void FAR *)ptr;
    far_ptr = (void FAR *)near_ptr;
 {
    void *near_ptr;
    void FAR *far_ptr;
    near_ptr = (void FAR *)ptr;
    far_ptr = (void FAR *)near_ptr;

-   if(check != 0)
-      if(far_ptr != ptr)
-         png_error(png_ptr,"segment lost in conversion");
+
+   if (check != 0)
+      if (far_ptr != ptr)
+         png_error(png_ptr, "segment lost in conversion");
+

    return(near_ptr);
 }
 #   endif
    return(near_ptr);
 }
 #   endif