1 files changed, 110 insertions, 0 deletions
diff --git a/src/util/dir_forest.c b/src/util/dir_forest.c
new file mode 100644
index 0000000..0070177
--- /dev/null
+++ b/src/util/dir_forest.c
@@ -0,0 +1,110 @@
+/*++
+/* NAME
+/*	dir_forest 3
+/* SUMMARY
+/*	file name to directory forest
+/* SYNOPSIS
+/*	#include <dir_forest.h>
+/*
+/*	char	*dir_forest(buf, path, depth)
+/*	VSTRING *buf;
+/*	const char *path;
+/*	int	depth;
+/* DESCRIPTION
+/*	This module implements support for directory forests: a file
+/*	organization that introduces one or more levels of intermediate
+/*	subdirectories in order to reduce the number of files per directory.
+/*
+/*	dir_forest() maps a file basename to a directory forest and
+/*	returns the resulting string: file name "abcd" becomes "a/b/"
+/*	and so on. The number of subdirectory levels is adjustable.
+/*
+/*	Arguments:
+/* .IP buf
+/*	A buffer that is overwritten with the result. The result
+/*	ends in "/" and is null terminated. If a null pointer is
+/*	specified, the result is written to a private buffer that
+/*	is overwritten upon each call.
+/* .IP path
+/*	A null-terminated string of printable characters. Characters
+/*	special to the file system are not permitted.
+/*	The first subdirectory is named after the first character
+/*	in \fIpath\fR, and so on. When the path is shorter than the
+/*	desired number of subdirectory levels, directory names
+/*	of '_' (underscore) are used as replacement.
+/* .IP depth
+/*	The desired number of subdirectory levels.
+/* DIAGNOSTICS
+/*	Panic: interface violations. Fatal error: out of memory.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <ctype.h>
+
+/* Utility library. */
+
+#include "msg.h"
+#include "dir_forest.h"
+
+/* dir_forest - translate base name to directory forest */
+
+char   *dir_forest(VSTRING *buf, const char *path, int depth)
+{
+    const char *myname = "dir_forest";
+    static VSTRING *private_buf = 0;
+    int     n;
+    const char *cp;
+    int     ch;
+
+    /*
+     * Sanity checks.
+     */
+    if (*path == 0)
+	msg_panic("%s: empty path", myname);
+    if (depth < 1)
+	msg_panic("%s: depth %d", myname, depth);
+
+    /*
+     * Your buffer or mine?
+     */
+    if (buf == 0) {
+	if (private_buf == 0)
+	    private_buf = vstring_alloc(1);
+	buf = private_buf;
+    }
+
+    /*
+     * Generate one or more subdirectory levels, depending on the pathname
+     * contents. When the pathname is short, use underscores instead.
+     * Disallow non-printable characters or characters that are special to
+     * the file system.
+     */
+    VSTRING_RESET(buf);
+    for (cp = path, n = 0; n < depth; n++) {
+	if ((ch = *cp) == 0) {
+	    ch = '_';
+	} else {
+	    if (!ISPRINT(ch) || ch == '.' || ch == '/')
+		msg_panic("%s: invalid pathname: %s", myname, path);
+	    cp++;
+	}
+	VSTRING_ADDCH(buf, ch);
+	VSTRING_ADDCH(buf, '/');
+    }
+    VSTRING_TERMINATE(buf);
+
+    if (msg_verbose > 1)
+	msg_info("%s: %s -> %s", myname, path, vstring_str(buf));
+    return (vstring_str(buf));
+}