[Alpha PATCH 1/6] util/hex-escape.[ch]: encoding/decoding strings into restricted character set
David Bremner
david at tethera.net
Tue Dec 13 12:27:50 PST 2011
From: David Bremner <bremner at debian.org>
The character set is chosen to be suitable for pathnames, and the same as that
used by contrib/nmbug
---
util/Makefile.local | 2 +-
util/hex-escape.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++++++
util/hex-escape.h | 15 +++++
3 files changed, 166 insertions(+), 1 deletions(-)
create mode 100644 util/hex-escape.c
create mode 100644 util/hex-escape.h
diff --git a/util/Makefile.local b/util/Makefile.local
index 26e4c3f..2e63932 100644
--- a/util/Makefile.local
+++ b/util/Makefile.local
@@ -3,7 +3,7 @@
dir := util
extra_cflags += -I$(srcdir)/$(dir)
-libutil_c_srcs := $(dir)/xutil.c $(dir)/error_util.c
+libutil_c_srcs := $(dir)/xutil.c $(dir)/error_util.c $(dir)/hex-escape.c
libutil_modules := $(libutil_c_srcs:.c=.o)
diff --git a/util/hex-escape.c b/util/hex-escape.c
new file mode 100644
index 0000000..3e08465
--- /dev/null
+++ b/util/hex-escape.c
@@ -0,0 +1,150 @@
+/* pathname.c - Manage encoding and decoding of byte strings into path names
+ *
+ * Copyright (c) 2011 David Bremner
+ *
+ * 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 3 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, see http://www.gnu.org/licenses/ .
+ *
+ * Author: David Bremner <david at tethera.net>
+ */
+
+#include <string.h>
+#include <talloc.h>
+#include "error_util.h"
+#include "hex-escape.h"
+
+static const size_t default_buf_size=1024;
+
+static const char* output_charset=
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-_@=.:,";
+
+static const char escape_char='%';
+
+static int
+is_output (char c) {
+ return (strchr (output_charset, c) != NULL);
+}
+
+
+static int
+maybe_realloc(void *ctx, size_t needed, char **out, size_t *out_size)
+{
+ if (*out_size < needed) {
+
+ if (*out == NULL)
+ *out = talloc_size(ctx,needed);
+ else
+ *out = talloc_realloc(ctx,*out,char,needed);
+
+ if (*out == NULL)
+ return 0;
+
+ *out_size = needed;
+ }
+ return 1;
+}
+
+
+hex_status_t
+hex_encode (void *ctx, const char *in, char **out, size_t *out_size)
+{
+
+ const char *p;
+ char *q;
+
+ int escape_count=0;
+ size_t needed;
+
+ for (p = in; *p; p++)
+ escape_count += (! is_output (*p));
+
+ needed = strlen (in) + 2*escape_count + 1;
+
+ if (*out == NULL)
+ *out_size=0;
+
+ if (!maybe_realloc (ctx, needed, out, out_size))
+ return HEX_OUT_OF_MEMORY;
+
+ q = *out;
+ p = in;
+
+ while (*p) {
+ if (is_output (*p)) {
+ *q++ = *p++;
+ } else {
+ sprintf (q, "%%%02x", *p++);
+ q += 3;
+ }
+ }
+
+ *q = '\0';
+ return HEX_SUCCESS;
+}
+
+
+hex_status_t
+hex_decode (void *ctx, const char *in, char **out, size_t *out_size) {
+
+ char buf[3];
+
+ const char *p;
+ char *q;
+
+ size_t escape_count = 0;
+ size_t needed = 0;
+
+ size_t len = strlen (in);
+
+ for (p = in; *p; p++)
+ escape_count += (*p == escape_char);
+
+ needed = len - escape_count*2 +1;
+
+ if (!maybe_realloc(ctx, needed, out, out_size))
+ return HEX_OUT_OF_MEMORY;
+
+ p = in;
+ q = *out;
+ buf[2]=0;
+
+
+ while (*p) {
+
+ if (*p == escape_char) {
+
+ char *endp;
+
+ if (len < 3)
+ return HEX_SYNTAX_ERROR;
+
+ buf[0]=p[1];
+ buf[1]=p[2];
+
+ *q = strtol(buf, &endp, 16);
+
+ if (endp != buf+2)
+ return HEX_SYNTAX_ERROR;
+
+ len -= 3;
+ p += 3;
+ q++;
+ } else {
+ *q++ = *p++;
+ }
+ }
+
+ *q = '\0';
+
+ return HEX_SUCCESS;
+}
diff --git a/util/hex-escape.h b/util/hex-escape.h
new file mode 100644
index 0000000..98ecbe0
--- /dev/null
+++ b/util/hex-escape.h
@@ -0,0 +1,15 @@
+#ifndef _HEX_ESCAPE_H
+#define _HEX_ESCAPE_H
+
+typedef enum hex_status {
+ HEX_SUCCESS = 0,
+ HEX_SYNTAX_ERROR,
+ HEX_OUT_OF_MEMORY
+} hex_status_t;
+
+hex_status_t
+hex_encode (void *talloc_ctx, const char *in, char **out, size_t *out_size);
+
+hex_status_t
+hex_decode (void *talloc_ctx, const char *in, char **out, size_t *out_size);
+#endif
--
1.7.5.4
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