X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2Fstdio%2Fsetvbuf.c;h=125a73f8808a32d341cd67710c1f0c0d7b9694e2;hb=393020b6e48719d27699dea6b29e53025bbd5123;hp=c6329df9b6f07fe823a2570e3d0b3533f6fca49a;hpb=90e52eb83afae4969bec36cd11ece85507458f79;p=pdclib

diff --git a/functions/stdio/setvbuf.c b/functions/stdio/setvbuf.c
index c6329df..125a73f 100644
--- a/functions/stdio/setvbuf.c
+++ b/functions/stdio/setvbuf.c
@@ -8,55 +8,70 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <limits.h>
 
 #ifndef REGTEST
 
 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.
-    */
-    if ( ( ! stream->status & _PDCLIB_VIRGINSTR ) ||
-         ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) )
+    switch ( mode )
     {
-        return -1;
-    }
-    /* If a buffer is provided by user... */
-    if ( buf != NULL )
-    {
-        /* ...do not free it in library functions like fclose(), freopen(). */
-        stream->status &= ~_PDCLIB_LIBBUFFER;
-    }
-    /* If no buffer is provided by user, but required... */
-    else if ( mode != _IONBF )
-    {
-        /* 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.
-        */
-        if ( ! ( stream->status & _PDCLIB_LIBBUFFER ) )
-        {
-            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 )
+        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 == NULL )
             {
+                /* PDCLib only supports buffers up to INT_MAX in size. A size
+                   of zero doesn't make sense.
+                */
                 return -1;
             }
+            if ( buf == NULL )
+            {
+                /* User requested buffer size, but leaves it to library to
+                   allocate the buffer.
+                */
+                if ( ( stream->bufsize < size ) || ( stream->bufsize > ( size << 1 ) ) )
+                {
+                    /* 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.
+                    */
+                    /* Free the buffer allocated by fopen(), and allocate a new
+                       one.
+                    */
+                    if ( ( buf = (char *) malloc( size ) ) == NULL )
+                    {
+                        /* Out of memory error. */
+                        return -1;
+                    }
+                }
+            }
+            else
+            {
+                /* User provided buffer -> set flag to not free() the buffer
+                   on fclose().
+                */
+                stream->status &= ~ _PDCLIB_LIBBUFFER;
+            }
             free( stream->buffer );
-        }
+            stream->buffer = buf;
+            stream->bufsize = size;
+            break;
+        default:
+            /* If mode is something else than _IOFBF, _IOLBF or _IONBF -> exit */
+            return -1;
     }
-    /* Applying new settings to stream. */
+    /* Deleting current buffer mode */
     stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+    /* Set user-defined mode */
     stream->status |= mode;
-    stream->buffer = buf;
-    stream->bufsize = size;
-    stream->status &= ~_PDCLIB_VIRGINSTR;
     return 0;
 }
 
@@ -65,10 +80,39 @@ int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_res
 #ifdef TEST
 #include <_PDCLIB_test.h>
 
+#include <errno.h>
+
+#define BUFFERSIZE 500
+
 int main( void )
 {
 #ifndef REGTEST
-    TESTCASE( NO_TESTDRIVER );
+    char const * const filename = "testfile";
+    char buffer[ BUFFERSIZE ];
+    FILE * fh;
+    remove( filename );
+    /* full buffered, user-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != 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 );
+    TESTCASE( remove( filename ) == 0 );
+    /* line buffered, lib-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != 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 );
+    TESTCASE( remove( filename ) == 0 );
+    /* not buffered, user-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+    TESTCASE( setvbuf( fh, buffer, _IONBF, BUFFERSIZE ) == 0 );
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IONBF );
+    TESTCASE( fclose( fh ) == 0 );
+    TESTCASE( remove( filename ) == 0 );
 #else
     puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
 #endif
@@ -76,3 +120,4 @@ int main( void )
 }
 
 #endif
+