X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=functions%2Fstdio%2Fftell.c;h=9ca449fe54a155d14bb747f0dca137aac8ede6c5;hp=9838156a3901f1f7f729f02d0e64b716bf5d2295;hb=393020b6e48719d27699dea6b29e53025bbd5123;hpb=f408c1fd633015089d2a0fc6bc31c9f61eeae0a9

diff --git a/functions/stdio/ftell.c b/functions/stdio/ftell.c
index 9838156..9ca449f 100644
--- a/functions/stdio/ftell.c
+++ b/functions/stdio/ftell.c
@@ -7,13 +7,26 @@
 */
 
 #include <stdio.h>
+#include <limits.h>
 
 #ifndef REGTEST
 
 long int ftell( struct _PDCLIB_file_t * stream )
 {
-    /* TODO: Implement. */
-    return 0;
+    /* TODO: A bit too fuzzy in the head now. stream->ungetidx should be in here
+             somewhere.
+    */
+    if ( stream->pos.offset > ( LONG_MAX - stream->bufidx ) )
+    {
+        /* integer overflow */
+        _PDCLIB_errno = _PDCLIB_EINVAL;
+        return -1;
+    }
+    /* Position of start-of-buffer, plus:
+       - buffered, unwritten content (for output streams), or
+       - already-parsed content from buffer (for input streams)
+    */
+    return (long int)( stream->pos.offset + stream->bufidx - stream->ungetidx );
 }
 
 #endif
@@ -21,10 +34,52 @@ long int ftell( struct _PDCLIB_file_t * stream )
 #ifdef TEST
 #include <_PDCLIB_test.h>
 
+#include <stdlib.h>
+
 int main( void )
 {
-    TESTCASE( NO_TESTDRIVER );
+    /* Testing all the basic I/O functions individually would result in lots
+       of duplicated code, so I took the liberty of lumping it all together
+       here.
+    */
+    /* The following functions delegate their tests to here:
+       fgetc fflush rewind fputc ungetc fseek
+       flushbuffer seek fillbuffer
+    */
+    char * buffer = (char*)malloc( 4 );
+    FILE * fh;
+    remove( "testfile" );
+    TESTCASE( ( fh = fopen( "testfile", "w+" ) ) != NULL );
+    TESTCASE( setvbuf( fh, buffer, _IOLBF, 4 ) == 0 );
+    TESTCASE( fputc( '1', fh ) == '1' );
+    TESTCASE( fputc( '2', fh ) == '2' );
+    TESTCASE( fputc( '3', fh ) == '3' );
+    /* Positions incrementing as expected? */
+    TESTCASE( ftell( fh ) == 3l );
+    TESTCASE_NOREG( fh->pos.offset == 0l );
+    TESTCASE_NOREG( fh->bufidx == 3l );
+    /* Buffer properly flushed when full? */
+    TESTCASE( fputc( '4', fh ) == '4' );
+    TESTCASE_NOREG( fh->pos.offset == 4l );
+    TESTCASE_NOREG( fh->bufidx == 0 );
+    /* fflush() resetting positions as expected? */
+    TESTCASE( fputc( '5', fh ) == '5' );
+    TESTCASE( fflush( fh ) == 0 );
+    TESTCASE( ftell( fh ) == 5l );
+    TESTCASE_NOREG( fh->pos.offset == 5l );
+    TESTCASE_NOREG( fh->bufidx == 0l );
+    /* rewind() resetting positions as expected? */
+    rewind( fh );
+    TESTCASE( ftell( fh ) == 0l );
+    TESTCASE_NOREG( fh->pos.offset == 0 );
+    TESTCASE_NOREG( fh->bufidx == 0 );
+    /* Reading back first character after rewind for basic read check */
+    TESTCASE( fgetc( fh ) == '1' );
+    TESTCASE( fclose( fh ) == 0 );
+    /* TODO: t.b.c. */
+    remove( "testfile" );
     return TEST_RESULTS;
 }
 
 #endif
+