Import 1.100

1 files changed, 80 insertions, 0 deletions

diff --git a/fsaf.h b/fsaf.h
new file mode 100644
index 0000000..a9a562c
--- /dev/null
+++ b/fsaf.h
@@ -0,0 +1,80 @@
+/*  dctrl-tools - Debian control file inspection tools
+    Copyright (C) 2003 Antti-Juhani Kaijanaho
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef FSAF_H
+#define FSAF_H
+
+#include <assert.h>
+#include <stdbool.h>
+
+/* FAST (MOSTLY) SEQUENTIAL-ACCESS FILE LAYER */
+
+struct fsaf_private {
+	int fd;
+	char * buf;
+	size_t buf_capacity;
+	size_t buf_offset;
+	size_t buf_size;
+	size_t invalid_mark;
+	size_t eof_mark; /* can be (size_t)(-1) if not reached yet */
+#ifdef _POSIX_MAPPED_FILES
+	bool mapped;
+	size_t topread; /* marks the top of what has been read ahead */
+#endif
+};
+
+typedef struct fsaf_private FSAF;
+
+/* Open a FSAF for the given fd. Only read access is supported for
+ * now.  The whole file is initially valid.  */
+FSAF * fsaf_fdopen(int fd);
+
+/* Close the given FSAF.  This DOES NOT close the underlying fd.  */
+void fsaf_close(FSAF *);
+
+/* Return a pointer to a buffer containing len bytes from the FSAF
+ * starting at offset.  Note that if offset is below the invalid mark,
+ * we return b = NULL.  This is a CHEAP operation, if the full range
+ * has already been accessed.  The buffer may be invalidated by any
+ * subsequent call to this function. */
+struct fsaf_read_rv {
+	char const * b;
+	size_t len;
+} fsaf_read(FSAF *, size_t offset, size_t len);
+
+static inline
+int fsaf_getc(FSAF * fp, size_t offset)
+{
+	if (offset >= fp->eof_mark) return -1;
+	struct fsaf_read_rv r = fsaf_read(fp, offset, 1);
+	if (offset >= fp->eof_mark) return -1;
+	assert(r.len == 1);
+	return (unsigned char)r.b[0];
+}
+
+
+/* Invalidate all bytes in FSAF up to and excluding offset.  */
+void fsaf_invalidate(FSAF *, size_t offset);
+
+/* Return an upper bound for the end of file, either the smallest
+ * offset beyond eof or (size_t)(-1). */
+static inline
+size_t fsaf_eof(FSAF * fp) { return fp->eof_mark; }
+
+
+#endif /* FSAF_H */