new function for file input. rewind the filedescriptor to the current

Tue Oct 27 07:25:53 1998  Tim Janik  <timj@gtk.org>

        * glib.h:
        * gscanner.c:
        (g_scanner_sync_file_offset): new function for file input.
        rewind the filedescriptor to the current buffer position and blow
        the file read ahead buffer. usefull for third party uses of our
        filedescriptor, which hooks onto the current scanning position.
        (this became neccessary with the implementation of buffered
        reads).
        (g_scanner_input_file):
        (g_scanner_input_text): automatically blow the read ahead buffer.
        (g_scanner_get_char): blow the read ahead buffer when the end of
        input is reached, i.e. a '\000' char is read.

1 files changed, 39 insertions, 0 deletions

diff --git a/gscanner.c b/gscanner.c
index 0372b1871..2bb0f471a 100644
--- a/gscanner.c
+++ b/gscanner.c
@@ -658,6 +658,9 @@ g_scanner_input_file (GScanner *scanner,
   g_return_if_fail (scanner != NULL);
   g_return_if_fail (input_fd >= 0);
 
+  if (scanner->input_fd >= 0)
+    g_scanner_sync_file_offset (scanner);
+
   scanner->token = G_TOKEN_NONE;
   scanner->value.v_int = 0;
   scanner->line = 1;
@@ -683,6 +686,9 @@ g_scanner_input_text (GScanner	  *scanner,
   else
     text = NULL;
 
+  if (scanner->input_fd >= 0)
+    g_scanner_sync_file_offset (scanner);
+
   scanner->token = G_TOKEN_NONE;
   scanner->value.v_int = 0;
   scanner->line = 1;
@@ -737,6 +743,33 @@ g_scanner_peek_next_char (GScanner *scanner)
     return 0;
 }
 
+void
+g_scanner_sync_file_offset (GScanner *scanner)
+{
+  g_return_if_fail (scanner != NULL);
+
+  /* for file input, rewind the filedescriptor to the current
+   * buffer position and blow the file read ahead buffer. usefull for
+   * third party uses of our filedescriptor, which hooks onto the current
+   * scanning position.
+   */
+
+  if (scanner->input_fd >= 0 && scanner->text_end > scanner->text)
+    {
+      gint buffered;
+
+      buffered = scanner->text_end - scanner->text;
+      if (lseek (scanner->input_fd, - buffered, SEEK_CUR) >= 0)
+	{
+	  /* we succeeded, blow our buffer's contents now */
+	  scanner->text = NULL;
+	  scanner->text_end = NULL;
+	}
+      else
+	errno = 0;
+    }
+}
+
 static guchar
 g_scanner_get_char (GScanner	*scanner,
 		    guint	*line_p,
@@ -768,6 +801,12 @@ g_scanner_get_char (GScanner	*scanner,
 	  scanner->text = buffer + 1;
 	  scanner->text_end = buffer + count;
 	  fchar = *buffer;
+	  if (!fchar)
+	    {
+	      g_scanner_sync_file_offset (scanner);
+	      scanner->text_end = scanner->text;
+	      scanner->input_fd = -1;
+	    }
 	}
     }
   else