X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=functions%2Fstdio%2Fsetvbuf.c;h=288211baefc7b5ea50e6b37ba941b503b3214f65;hp=9d96ad8f8583e3681e8bdfa8d162c613a6231cab;hb=da0f3f353d417fed71f358a48d5d5394145e460d;hpb=b08f4b52b1cd1f7a9553c0f357a7c90859fa3e73

diff --git a/functions/stdio/setvbuf.c b/functions/stdio/setvbuf.c
index 9d96ad8..288211b 100644
--- a/functions/stdio/setvbuf.c
+++ b/functions/stdio/setvbuf.c
@@ -1,5 +1,3 @@
-/* $Id$ */
-
 /* setvbuf( FILE *, char *, int, size_t )
 
    This file is part of the Public Domain C Library (PDCLib).
@@ -8,34 +6,110 @@
 
 #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 )
 {
-    /* TODO: Only allowed on a "virgin" stream; add check. */
-    if ( ( stream->status & ( _IOFBF | _IOLBF | _IONBF ) ) /* Only allowed on "virgin" stream */
-      || ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) /* invalid mode */
-      || ( ( buf == NULL ) && ( ( buf = malloc( size ) ) == NULL ) ) /* no memory available */
-    )
+    _PDCLIB_flockfile( stream );
+    switch ( mode )
     {
-        return -1;
+        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;
-    stream->buffer  = buf;
-    stream->bufsize = size;
+    _PDCLIB_funlockfile( stream );
     return 0;
 }
 
 #endif
 
 #ifdef TEST
-#include <_PDCLIB_test.h>
+#include "_PDCLIB_test.h"
+#include <errno.h>
+#ifndef REGTEST
+#include "_PDCLIB_io.h"
+#endif
+#define BUFFERSIZE 500
 
 int main( void )
 {
-    TESTCASE( NO_TESTDRIVER );
+#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
+