--- /dev/null
+
+/* pngwio.c - functions for data output
+ *
+ * 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 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
+ * use different output methods. Note that you shouldn't change these
+ * functions, but rather write replacement functions and then change
+ * them at run time with png_set_write_fn(...).
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+/* 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.
+ */
+
+void /* PRIVATE */
+png_write_data(png_structp png_ptr, png_const_bytep data, png_size_t length)
+{
+ /* NOTE: write_data_fn must not change the buffer! */
+ if (png_ptr->write_data_fn != NULL )
+ (*(png_ptr->write_data_fn))(png_ptr, (png_bytep)data, length);
+
+ else
+ png_error(png_ptr, "Call to NULL write function");
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+/* 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.
+ */
+#ifndef USE_FAR_KEYWORD
+void PNGCBAPI
+png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+ png_size_t check;
+
+ if (png_ptr == NULL)
+ return;
+
+ check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
+
+ 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.
+ */
+
+#define NEAR_BUF_SIZE 1024
+#define MIN(a,b) (a <= b ? a : b)
+
+void PNGCBAPI
+png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+ png_uint_32 check;
+ 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 = fwrite(near_data, 1, length, io_ptr);
+ }
+
+ else
+ {
+ png_byte buf[NEAR_BUF_SIZE];
+ png_size_t written, remaining, err;
+ check = 0;
+ remaining = length;
+
+ do
+ {
+ written = MIN(NEAR_BUF_SIZE, remaining);
+ png_memcpy(buf, data, written); /* Copy far buffer to near buffer */
+ err = fwrite(buf, 1, written, io_ptr);
+
+ if (err != written)
+ break;
+
+ else
+ check += err;
+
+ data += written;
+ remaining -= written;
+ }
+ while (remaining != 0);
+ }
+
+ if (check != length)
+ png_error(png_ptr, "Write Error");
+}
+
+#endif
+#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.
+ */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+void /* PRIVATE */
+png_flush(png_structp png_ptr)
+{
+ if (png_ptr->output_flush_fn != NULL)
+ (*(png_ptr->output_flush_fn))(png_ptr);
+}
+
+# ifdef PNG_STDIO_SUPPORTED
+void PNGCBAPI
+png_default_flush(png_structp png_ptr)
+{
+ png_FILE_p io_ptr;
+
+ if (png_ptr == NULL)
+ return;
+
+ io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
+ fflush(io_ptr);
+}
+# 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. 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)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->io_ptr = io_ptr;
+
+#ifdef PNG_STDIO_SUPPORTED
+ 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
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+# ifdef PNG_STDIO_SUPPORTED
+
+ if (output_flush_fn != NULL)
+ png_ptr->output_flush_fn = output_flush_fn;
+
+ else
+ png_ptr->output_flush_fn = png_default_flush;
+
+# else
+ png_ptr->output_flush_fn = output_flush_fn;
+# endif
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+
+ /* It is an error to read while writing a png file */
+ if (png_ptr->read_data_fn != NULL)
+ {
+ png_ptr->read_data_fn = NULL;
+
+ png_warning(png_ptr,
+ "Can't set both read_data_fn and write_data_fn in the"
+ " same structure");
+ }
+}
+
+#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;
+
+ if (check != 0)
+ if (FP_SEG(ptr) != FP_SEG(far_ptr))
+ png_error(png_ptr, "segment lost in conversion");
+
+ return(near_ptr);
+}
+# else
+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;
+
+ if (check != 0)
+ if (far_ptr != ptr)
+ png_error(png_ptr, "segment lost in conversion");
+
+ return(near_ptr);
+}
+# endif
+#endif
+#endif /* PNG_WRITE_SUPPORTED */
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