From d655f5154c5a3d21a6ca3e7ff2cee9ba5e2ad0b3 Mon Sep 17 00:00:00 2001
From: solar <unknown>
Date: Wed, 14 Jun 2006 05:10:43 +0000
Subject: [PATCH] Skeleton implementation for now.

---
 functions/stdio/setvbuf.c | 104 ++++++++++++++++++++++++++++----------
 1 file changed, 76 insertions(+), 28 deletions(-)

diff --git a/functions/stdio/setvbuf.c b/functions/stdio/setvbuf.c
index c6329df..5ac14a9 100644
--- a/functions/stdio/setvbuf.c
+++ b/functions/stdio/setvbuf.c
@@ -13,51 +13,65 @@
 
 int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
 {
-    /* Only allowed on "virgin" streams (i.e., before first I/O occurs), and
-       a valid value for mode.
+    /* TODO: Honor user-provided buffer / buffer size. (Not actually required
+       by the standard...) */
+    stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+    stream->status |= mode; /* TODO: Unchecked use of mode -> vulnerable. */
+    return 0;
+
+#if 0
+    /* Only allowed on "virgin" streams (i.e., before first I/O occurs), a
+       valid value for mode, and only once per stream (i.e., the buffer
+       attached to the stream should always be the one allocated by fopen().
     */
     if ( ( ! stream->status & _PDCLIB_VIRGINSTR ) ||
-         ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) )
+         ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) ||
+         ! ( stream->status & _PDCLIB_LIBBUFFER ) )
     {
         return -1;
     }
-    /* If a buffer is provided by user... */
-    if ( buf != NULL )
+    if ( mode == _IONBF )
     {
-        /* ...do not free it in library functions like fclose(), freopen(). */
-        stream->status &= ~_PDCLIB_LIBBUFFER;
+        /* When unbuffered I/O is requested, we don't need a buffer. */
+        buf = NULL;
+        size = 0;
     }
-    /* If no buffer is provided by user, but required... */
-    else if ( mode != _IONBF )
+    else
     {
-        /* Since setvbuf() may be called (successfully) on a stream only once,
-           the stream's buffer at this point should *always* be that allocated
-           by fopen(), but better make sure.
+        /* The standard does not really require this - only BUFSIZ is required
+           to be no smaller than 256 - but it makes sense not to make buffers
+           too small anyway.
         */
-        if ( ! ( stream->status & _PDCLIB_LIBBUFFER ) )
+        if ( size < 256 )
         {
-            return -1;
-        }
-        /* Drop old buffer, allocate new one of requested size (unless that is
-           equal to BUFSIZ, in which case we can use the one already allocated
-           by fopen().)
-        */
-        if ( size != BUFSIZ )
-        {
-            if ( ( buf = malloc( size ) ) == NULL )
-            {
-                return -1;
-            }
-            free( stream->buffer );
+            buf = NULL; /* do not use too-small user buffer */
+            size = 256;
         }
     }
+    /* If a suitable buffer is provided by user... */
+    if ( buf != NULL )
+    {
+        /* ...do not free it in library functions like fclose(), freopen(). */
+        stream->status &= ~_PDCLIB_LIBBUFFER;
+    }
+    /* If we cannot allocate enough memory, that is not a reason for failure -
+       the standard does not actually *require* that setvbuf() honors user-
+       supplied buffer and buffer size, so we can quietly ignore this.
+    */
+    /* FIXME: Logic stops here. Handle _IONBF, new buf value etc. correctly. */
+    puts("foo");
+    if ( ( ( buf = malloc( size ) ) != NULL ) || ( mode == _IONBF ) )
+    {
+        free( stream->buffer );
+    }
+    puts("bar");
     /* Applying new settings to stream. */
     stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
     stream->status |= mode;
-    stream->buffer = buf;
     stream->bufsize = size;
     stream->status &= ~_PDCLIB_VIRGINSTR;
     return 0;
+#endif
 }
 
 #endif
@@ -65,10 +79,44 @@ int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_res
 #ifdef TEST
 #include <_PDCLIB_test.h>
 
+#define BUFFERSIZE 500
+
 int main( void )
 {
 #ifndef REGTEST
-    TESTCASE( NO_TESTDRIVER );
+    char const * const filename = "testfile";
+    char buffer[ BUFFERSIZE ];
+    struct _PDCLIB_file_t * fh;
+    /* full buffered, user-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+    TESTCASE( fh->status & _PDCLIB_LIBBUFFER );
+    TESTCASE( fh->bufsize == BUFSIZ );
+    TESTCASE( setvbuf( fh, buffer, _IOFBF, BUFFERSIZE ) == 0 );
+#if 0
+    TESTCASE( fh->buffer == buffer );
+    TESTCASE( fh->bufsize == BUFFERSIZE );
+#endif
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOFBF );
+    TESTCASE( fclose( fh ) == 0 );
+    /* line buffered, lib-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+    TESTCASE( setvbuf( fh, NULL, _IOLBF, BUFFERSIZE ) == 0 );
+#if 0
+    TESTCASE( fh->buffer != buffer );
+    TESTCASE( fh->buffer != NULL );
+    TESTCASE( fh->bufsize == BUFFERSIZE );
+#endif
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOLBF );
+    TESTCASE( fclose( fh ) == 0 );
+    /* not buffered, user-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+    TESTCASE( setvbuf( fh, buffer, _IONBF, BUFFERSIZE ) == 0 );
+#if 0
+    TESTCASE( fh->buffer == NULL );
+    TESTCASE( fh->bufsize == 0 );
+#endif
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IONBF );
+    TESTCASE( fclose( fh ) == 0 );
 #else
     puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
 #endif
-- 
2.40.0