[PATCH 01/16] hex-escape: (en|de)code strings to/from restricted character set

[da...@tethera.net]

From: David Bremner 

The character set is chosen to be suitable for pathnames, and the same
as that used by contrib/nmbug

[With additions by Jani Nikula]
---
 util/Makefile.local |2 +-
 util/hex-escape.c   |  168 +++
 util/hex-escape.h   |   41 +
 3 files changed, 210 insertions(+), 1 deletion(-)
 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 c7cae61..3ca623e 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 000..d8905d0
--- /dev/null
+++ b/util/hex-escape.c
@@ -0,0 +1,168 @@
+/* hex-escape.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 
+ */
+
+#include 
+#include 
+#include 
+#include 
+#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 unsigned char *p;
+char *q;
+
+size_t escape_count = 0;
+size_t len = 0;
+size_t needed;
+
+assert (ctx); assert (in); assert (out); assert (out_size);
+
+for (p = (unsigned char *) in; *p; p++) {
+   escape_count += (!is_output (*p));
+   len++;
+}
+
+needed = len + escape_count * 2 + 1;
+
+if (*out == NULL)
+   *out_size = 0;
+
+if (!maybe_realloc (ctx, needed, out, out_size))
+   return HEX_OUT_OF_MEMORY;
+
+q = *out;
+p = (unsigned char *) in;
+
+while (*p) {
+   if (is_output (*p)) {
+   *q++ = *p++;
+   } else {
+   sprintf (q, "%%%02x", *p++);
+   q += 3;
+   }
+}
+
+*q = '\0';
+return HEX_SUCCESS;
+}
+
+/* Hex decode 'in' to 'out'.
+ *
+ * This must succeed for in == out to support hex_decode_inplace().
+ */
+static hex_status_t
+hex_decode_internal (const char *in, unsigned char *out)
+{
+char buf[3];
+
+while (*in) {
+   if (*in == escape_char) {
+   char *endp;
+
+   /* This also handles unexpected end-of-string. */
+   if (!isxdigit ((unsigned char) in[1]) ||
+   !isxdigit ((unsigned char) in[2]))
+   return HEX_SYNTAX_ERROR;
+
+   buf[0] = in[1];
+   buf[1] = in[2];
+   buf[2] = '\0';
+
+   *out = strtoul (buf, , 16);
+
+   if (endp != buf + 2)
+   return HEX_SYNTAX_ERROR;
+
+   in += 3;
+   out++;
+   } else {
+   *out++ = *in++;
+   }
+}
+
+*out = '\0';
+
+return HEX_SUCCESS;
+}
+
+hex_status_t
+hex_decode_inplace (char *s)
+{
+/* A decoded string is never longer than the encoded one, so it is
+ * safe to decode a string onto itself. */
+return hex_decode_internal (s, (unsigned char *) s);
+}
+
+hex_status_t
+hex_decode (void *ctx, const char *in, char **out, size_t * out_size)
+{
+const char *p;
+size_t escape_count = 0;
+size_t needed = 0;
+
+assert (ctx); assert (in); assert (out); assert (out_size);
+
+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;
+
+return hex_decode_internal 

[PATCH 01/16] hex-escape: (en|de)code strings to/from restricted character set

[david]

From: David Bremner brem...@debian.org

The character set is chosen to be suitable for pathnames, and the same
as that used by contrib/nmbug

[With additions by Jani Nikula]
---
 util/Makefile.local |2 +-
 util/hex-escape.c   |  168 +++
 util/hex-escape.h   |   41 +
 3 files changed, 210 insertions(+), 1 deletion(-)
 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 c7cae61..3ca623e 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 000..d8905d0
--- /dev/null
+++ b/util/hex-escape.c
@@ -0,0 +1,168 @@
+/* hex-escape.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 da...@tethera.net
+ */
+
+#include assert.h
+#include string.h
+#include talloc.h
+#include ctype.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 unsigned char *p;
+char *q;
+
+size_t escape_count = 0;
+size_t len = 0;
+size_t needed;
+
+assert (ctx); assert (in); assert (out); assert (out_size);
+
+for (p = (unsigned char *) in; *p; p++) {
+   escape_count += (!is_output (*p));
+   len++;
+}
+
+needed = len + escape_count * 2 + 1;
+
+if (*out == NULL)
+   *out_size = 0;
+
+if (!maybe_realloc (ctx, needed, out, out_size))
+   return HEX_OUT_OF_MEMORY;
+
+q = *out;
+p = (unsigned char *) in;
+
+while (*p) {
+   if (is_output (*p)) {
+   *q++ = *p++;
+   } else {
+   sprintf (q, %%%02x, *p++);
+   q += 3;
+   }
+}
+
+*q = '\0';
+return HEX_SUCCESS;
+}
+
+/* Hex decode 'in' to 'out'.
+ *
+ * This must succeed for in == out to support hex_decode_inplace().
+ */
+static hex_status_t
+hex_decode_internal (const char *in, unsigned char *out)
+{
+char buf[3];
+
+while (*in) {
+   if (*in == escape_char) {
+   char *endp;
+
+   /* This also handles unexpected end-of-string. */
+   if (!isxdigit ((unsigned char) in[1]) ||
+   !isxdigit ((unsigned char) in[2]))
+   return HEX_SYNTAX_ERROR;
+
+   buf[0] = in[1];
+   buf[1] = in[2];
+   buf[2] = '\0';
+
+   *out = strtoul (buf, endp, 16);
+
+   if (endp != buf + 2)
+   return HEX_SYNTAX_ERROR;
+
+   in += 3;
+   out++;
+   } else {
+   *out++ = *in++;
+   }
+}
+
+*out = '\0';
+
+return HEX_SUCCESS;
+}
+
+hex_status_t
+hex_decode_inplace (char *s)
+{
+/* A decoded string is never longer than the encoded one, so it is
+ * safe to decode a string onto itself. */
+return hex_decode_internal (s, (unsigned char *) s);
+}
+
+hex_status_t
+hex_decode (void *ctx, const char *in, char **out, size_t * out_size)
+{
+const char *p;
+size_t escape_count = 0;
+size_t needed = 0;
+
+assert (ctx); assert (in); assert (out); assert (out_size);
+
+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