[PATCHv3 11/13] strbuf: add strbuf_add*_urlencode

[Jeff King <peff@peff.net>]

This just follows the rfc3986 rules for percent-encoding
url data into a strbuf.

Signed-off-by: Jeff King <peff@peff.net>
---
 strbuf.c |   37 +++++++++++++++++++++++++++++++++++++
 strbuf.h |    5 +++++
 2 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/strbuf.c b/strbuf.c
index a849705..ff0b96b 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -411,3 +411,40 @@ void strbuf_add_lines(struct strbuf *out, const char *prefix,
 	}
 	strbuf_complete_line(out);
 }
+
+static int is_rfc3986_reserved(char ch)
+{
+	switch (ch) {
+		case '!': case '*': case '\'': case '(': case ')': case ';':
+		case ':': case '@': case '&': case '=': case '+': case '$':
+		case ',': case '/': case '?': case '#': case '[': case ']':
+			return 1;
+	}
+	return 0;
+}
+
+static int is_rfc3986_unreserved(char ch)
+{
+	return isalnum(ch) ||
+		ch == '-' || ch == '_' || ch == '.' || ch == '~';
+}
+
+void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
+			  int reserved)
+{
+	strbuf_grow(sb, len);
+	while (len--) {
+		char ch = *s++;
+		if (is_rfc3986_unreserved(ch) ||
+		    (!reserved && is_rfc3986_reserved(ch)))
+			strbuf_addch(sb, ch);
+		else
+			strbuf_addf(sb, "%%%02x", ch);
+	}
+}
+
+void strbuf_addstr_urlencode(struct strbuf *sb, const char *s,
+			     int reserved)
+{
+	strbuf_add_urlencode(sb, s, strlen(s), reserved);
+}
diff --git a/strbuf.h b/strbuf.h
index 08fc13d..fbf059f 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -123,4 +123,9 @@ static inline void strbuf_complete_line(struct strbuf *sb)
 extern int strbuf_branchname(struct strbuf *sb, const char *name);
 extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
 
+extern void strbuf_add_urlencode(struct strbuf *, const char *, size_t,
+				 int reserved);
+extern void strbuf_addstr_urlencode(struct strbuf *, const char *,
+				    int reserved);
+
 #endif /* STRBUF_H */
-- 
1.7.8.rc2.40.gaf387