X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=functions%2Fstdio%2Fsetvbuf.c;h=288211baefc7b5ea50e6b37ba941b503b3214f65;hp=a65dd8ed2528265395ed99ea4036a1e7c135bf52;hb=da0f3f353d417fed71f358a48d5d5394145e460d;hpb=34893ecc2200dc7017c36a54cb6c5f4c2378b5ec

diff --git a/functions/stdio/setvbuf.c b/functions/stdio/setvbuf.c
index a65dd8e..288211b 100644
--- a/functions/stdio/setvbuf.c
+++ b/functions/stdio/setvbuf.c
@@ -1,8 +1,115 @@
-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
-
-int setvbuf( FILE * restrict stream, char * restrict buf, int mode, size_t size ) { /* TODO */ };
+/* setvbuf( FILE *, char *, int, size_t )
+
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+
+#ifndef REGTEST
+#include "_PDCLIB_io.h"
+
+int setvbuf( FILE * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
+{
+    _PDCLIB_flockfile( stream );
+    switch ( mode )
+    {
+        case _IONBF:
+            /* When unbuffered I/O is requested, we keep the buffer anyway, as
+               we don't want to e.g. flush the stream for every character of a
+               stream being printed.
+            */
+            break;
+        case _IOFBF:
+        case _IOLBF:
+            if ( size > INT_MAX || size == 0 )
+            {
+                /* PDCLib only supports buffers up to INT_MAX in size. A size
+                   of zero doesn't make sense.
+                */
+                _PDCLIB_funlockfile( stream );
+                return -1;
+            }
+            if ( buf == NULL )
+            {
+                /* User requested buffer size, but leaves it to library to
+                   allocate the buffer.
+                */
+                /* If current buffer is big enough for requested size, but not
+                   over twice as big (and wasting memory space), we use the
+                   current buffer (i.e., do nothing), to save the malloc() / 
+                   free() overhead.
+                */
+                if ( ( stream->bufsize < size ) || ( stream->bufsize > ( size << 1 ) ) )
+                {
+                    /* Buffer too small, or much too large - allocate. */
+                    if ( ( buf = (char *) malloc( size ) ) == NULL )
+                    {
+                        /* Out of memory error. */
+                        _PDCLIB_funlockfile( stream );
+                        return -1;
+                    }
+                    /* This buffer must be free()d on fclose() */
+                    stream->status |= _PDCLIB_FREEBUFFER;
+                }
+            }
+            stream->buffer = buf;
+            stream->bufsize = size;
+            break;
+        default:
+            /* If mode is something else than _IOFBF, _IOLBF or _IONBF -> exit */
+            _PDCLIB_funlockfile( stream );
+            return -1;
+    }
+    /* Deleting current buffer mode */
+    stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+    /* Set user-defined mode */
+    stream->status |= mode;
+    _PDCLIB_funlockfile( stream );
+    return 0;
+}
+
+#endif
+
+#ifdef TEST
+#include "_PDCLIB_test.h"
+#include <errno.h>
+#ifndef REGTEST
+#include "_PDCLIB_io.h"
+#endif
+#define BUFFERSIZE 500
+
+int main( void )
+{
+#ifndef REGTEST
+    char buffer[ BUFFERSIZE ];
+    FILE * fh;
+    /* full buffered, user-supplied buffer */
+    TESTCASE( ( fh = tmpfile() ) != NULL );
+    TESTCASE( setvbuf( fh, buffer, _IOFBF, BUFFERSIZE ) == 0 );
+    TESTCASE( fh->buffer == buffer );
+    TESTCASE( fh->bufsize == BUFFERSIZE );
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOFBF );
+    TESTCASE( fclose( fh ) == 0 );
+    /* line buffered, lib-supplied buffer */
+    TESTCASE( ( fh = tmpfile() ) != NULL );
+    TESTCASE( setvbuf( fh, NULL, _IOLBF, BUFFERSIZE ) == 0 );
+    TESTCASE( fh->buffer != NULL );
+    TESTCASE( fh->bufsize == BUFFERSIZE );
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOLBF );
+    TESTCASE( fclose( fh ) == 0 );
+    /* not buffered, user-supplied buffer */
+    TESTCASE( ( fh = tmpfile() ) != NULL );
+    TESTCASE( setvbuf( fh, buffer, _IONBF, BUFFERSIZE ) == 0 );
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IONBF );
+    TESTCASE( fclose( fh ) == 0 );
+#else
+    puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
+#endif
+    return TEST_RESULTS;
+}
+
+#endif
+