fwrite: output line buffered content as we go along

[pdclib.old] / functions / stdio / fwrite.c

diff --git a/functions/stdio/fwrite.c b/functions/stdio/fwrite.c
index d3e58592f1c7eab5c1d0ac0bc0ec5f36b08d7a72..d0efadb207df354eabdca050be5819c1756a370d 100644 (file)
--- a/functions/stdio/fwrite.c
+++ b/functions/stdio/fwrite.c
@@ -7,79 +7,64 @@
 */
 
 #include <stdio.h>
-#include <_PDCLIB_glue.h>
 
 #ifndef REGTEST
+#include <_PDCLIB_io.h>
+#include <_PDCLIB_glue.h>
 
 #include <stdbool.h>
 #include <string.h>
 
-size_t fwrite( const void * _PDCLIB_restrict ptr, size_t size, size_t nmemb, struct _PDCLIB_file_t * _PDCLIB_restrict stream )
+size_t _PDCLIB_fwrite_unlocked( const void *restrict vptr,
+               size_t size, size_t nmemb,
+               FILE * _PDCLIB_restrict stream )
 {
     if ( _PDCLIB_prepwrite( stream ) == EOF )
     {
         return 0;
     }
-    _PDCLIB_size_t offset = 0;
-    bool lineend = false;
+
+    const char *restrict ptr = vptr;
     size_t nmemb_i;
     for ( nmemb_i = 0; nmemb_i < nmemb; ++nmemb_i )
     {
         for ( size_t size_i = 0; size_i < size; ++size_i )
         {
-            /* TODO: Should line-buffered streams be flushed on '\n' or system EOL? */
-            if ( ( stream->buffer[ stream->bufidx++ ] == ((char*)ptr)[ nmemb_i * size + size_i ] ) == '\n' )
-            {
-                /* Remember last newline, in case we have to do a partial line-buffered flush */
-                offset = stream->bufidx;
-                lineend = true;
-            }
-            if ( stream->bufidx == stream->bufsize )
+            char c = ptr[ nmemb_i * size + size_i ];
+            stream->buffer[ stream->bufidx++ ] = c;
+
+            if ( stream->bufidx == stream->bufsize || ( c == '\n' && stream->status & _IOLBF ) )
             {
                 if ( _PDCLIB_flushbuffer( stream ) == EOF )
                 {
                     /* Returning number of objects completely buffered */
                     return nmemb_i;
                 }
-                lineend = false;
             }
         }
-    }
-    /* Fully-buffered streams are OK. Non-buffered streams must be flushed,
-       line-buffered streams only if there's a newline in the buffer.
-    */
-    switch ( stream->status & ( _IONBF | _IOLBF ) )
-    {
-        case _IONBF:
-            if ( _PDCLIB_flushbuffer( stream ) == EOF )
-            {
-                /* We are in a pinch here. We have an error, which requires a
-                   return value < nmemb. On the other hand, all objects have
-                   been written to buffer, which means all the caller had to
-                   do was removing the error cause, and re-flush the stream...
-                   Catch 22. We'll return a value one short, to indicate the
-                   error, and can't really do anything about the inconsistency.
-                */
-                return nmemb_i - 1;
-            }
-            break;
-        case _IOLBF:
-            {
-            size_t bufidx = stream->bufidx;
-            stream->bufidx = offset;
+
+        if ( stream->status & _IONBF )
+        {
             if ( _PDCLIB_flushbuffer( stream ) == EOF )
             {
-                /* See comment above. */
-                stream->bufidx = bufidx;
-                return nmemb_i - 1;
-            }
-            stream->bufidx = bufidx - offset;
-            memmove( stream->buffer, stream->buffer + offset, stream->bufidx );
+                /* Returning number of objects completely buffered */
+                return nmemb_i;
             }
+        }
     }
     return nmemb_i;
 }
 
+size_t fwrite( const void * _PDCLIB_restrict ptr,
+               size_t size, size_t nmemb,
+               FILE * _PDCLIB_restrict stream )
+{
+    _PDCLIB_flockfile( stream );
+    size_t r = _PDCLIB_fwrite_unlocked( ptr, size, nmemb, stream );
+    _PDCLIB_funlockfile( stream );
+    return r;
+}
+
 #endif
 
 #ifdef TEST
@@ -87,13 +72,7 @@ size_t fwrite( const void * _PDCLIB_restrict ptr, size_t size, size_t nmemb, str
 
 int main( void )
 {
-    FILE * fh;
-    remove( "testfile" );
-    TESTCASE( ( fh = fopen( "testfile", "w" ) ) != NULL );
-    TESTCASE( fwrite( "SUCCESS testing fwrite()\n", 1, 25, fh ) == 25 );
-    TESTCASE( fclose( fh ) == 0 );
-    /* TODO: Add readback test. */
-    TESTCASE( remove( "testfile" ) == 0 );
+    /* Testing covered by fread(). */
     return TEST_RESULTS;
 }