url: Split out the URL encoding and decoding functions

We want to use these as the format for encoding binary data
in our PKCS#11 attribute persistence

https://bugs.freedesktop.org/show_bug.cgi?id=62156

1 files changed, 142 insertions, 0 deletions

diff --git a/common/url.c b/common/url.c
new file mode 100644
index 0000000..6ccf74d
--- /dev/null
+++ b/common/url.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2011 Collabora Ltd.
+ * Copyright (C) 2013 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *     * Redistributions of source code must retain the above
+ *       copyright notice, this list of conditions and the
+ *       following disclaimer.
+ *     * Redistributions in binary form must reproduce the
+ *       above copyright notice, this list of conditions and
+ *       the following disclaimer in the documentation and/or
+ *       other materials provided with the distribution.
+ *     * The names of contributors to this software may not be
+ *       used to endorse or promote products derived from this
+ *       software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+ * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * Author: Stef Walter <stefw@collabora.co.uk>
+ */
+
+#include "config.h"
+
+#include "debug.h"
+#include "url.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+const static char HEX_CHARS[] = "0123456789abcdef";
+
+unsigned char *
+p11_url_decode (const char *value,
+                const char *end,
+                const char *skip,
+                size_t *length)
+{
+	char *a, *b;
+	unsigned char *result, *p;
+
+	assert (value <= end);
+	assert (skip != NULL);
+
+	/* String can only get shorter */
+	result = malloc ((end - value) + 1);
+	return_val_if_fail (result != NULL, NULL);
+
+	/* Now loop through looking for escapes */
+	p = result;
+	while (value != end) {
+		/*
+		 * A percent sign followed by two hex digits means
+		 * that the digits represent an escaped character.
+		 */
+		if (*value == '%') {
+			value++;
+			if (value + 2 > end) {
+				free (result);
+				return NULL;
+			}
+			a = strchr (HEX_CHARS, tolower (value[0]));
+			b = strchr (HEX_CHARS, tolower (value[1]));
+			if (!a || !b) {
+				free (result);
+				return NULL;
+			}
+			*p = (a - HEX_CHARS) << 4;
+			*(p++) |= (b - HEX_CHARS);
+			value += 2;
+
+		/* Ignore whitespace characters */
+		} else if (strchr (skip, *value)) {
+			value++;
+
+		/* A different character */
+		} else {
+			*(p++) = *(value++);
+		}
+	}
+
+	/* Null terminate string, in case its a string */
+	*p = 0;
+
+	if (length)
+		*length = p - result;
+	return result;
+}
+
+char *
+p11_url_encode (const unsigned char *value,
+                const unsigned char *end,
+                const char *verbatim,
+                size_t *length)
+{
+	char *p;
+	char *result;
+
+	assert (value <= end);
+
+	/* Just allocate for worst case */
+	result = malloc (((end - value) * 3) + 1);
+	return_val_if_fail (result != NULL, NULL);
+
+	/* Now loop through looking for escapes */
+	p = result;
+	while (value != end) {
+
+		/* These characters we let through verbatim */
+		if (*value && strchr (verbatim, *value) != NULL) {
+			*(p++) = *(value++);
+
+		/* All others get encoded */
+		} else {
+			*(p++) = '%';
+			*(p++) = HEX_CHARS[((unsigned char)*value) >> 4];
+			*(p++) = HEX_CHARS[((unsigned char)*value) & 0x0F];
+			++value;
+		}
+	}
+
+	*p = 0;
+	if (length)
+		*length = p - result;
+	return result;
+}