hex: allow specifying hex type with hex2chr

We have several places where we use hex2chr.  One of those is parsing
object IDs, but others decode quoted-printable or percent encoding.  All
of them accept both uppercase and lowercase hex.

In a future commit, we'll change some of these cases, so make hex2chr
accept the kind of encoding to use: lowercase only hex or any kind of
hex.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

hex-ll.h

@@ -17,10 +17,10 @@ static inline unsigned int hexval(unsigned char c, enum hexkind kind)
  * Convert two consecutive hexadecimal digits into a char.  Return a
  * negative value on error.  Don't run over the end of short strings.
  */
-static inline int hex2chr(const char *s)
+static inline int hex2chr(const char *s, enum hexkind kind)
 {
-	unsigned int val = hexval(s[0], HEX_KIND_MIXED);
-	return (val & ~0xf) ? val : (val << 4) | hexval(s[1], HEX_KIND_MIXED);
+	unsigned int val = hexval(s[0], kind);
+	return (val & ~0xf) ? val : (val << 4) | hexval(s[1], kind);
 }
 
 /*

hex.c

@@ -9,7 +9,7 @@ static int get_hash_hex_algop(const char *hex, unsigned char *hash,
 			      const struct git_hash_algo *algop)
 {
 	for (size_t i = 0; i < algop->rawsz; i++) {
-		int val = hex2chr(hex);
+		int val = hex2chr(hex, HEX_KIND_MIXED);
 		if (val < 0)
 			return -1;
 		*hash++ = val;

mailinfo.c

@@ -396,7 +396,7 @@ static int decode_q_segment(struct strbuf *out, const struct strbuf *q_seg,
 			int ch, d = *in;
 			if (d == '\n' || !d)
 				break; /* drop trailing newline */
-			ch = hex2chr(in);
+			ch = hex2chr(in, HEX_KIND_MIXED);
 			if (ch >= 0) {
 				strbuf_addch(out, ch);
 				in += 2;

ref-filter.c

@@ -3567,7 +3567,7 @@ static void append_literal(const char *cp, const char *ep, struct ref_formatting
 			if (cp[1] == '%')
 				cp++;
 			else {
-				int ch = hex2chr(cp + 1);
+				int ch = hex2chr(cp + 1, HEX_KIND_MIXED);
 				if (0 <= ch) {
 					strbuf_addch(s, ch);
 					cp += 3;

strbuf.c

@@ -457,7 +457,7 @@ size_t strbuf_expand_literal(struct strbuf *sb, const char *placeholder)
 		return 1;
 	case 'x':
 		/* %x00 == NUL, %x0a == LF, etc. */
-		ch = hex2chr(placeholder + 1);
+		ch = hex2chr(placeholder + 1, HEX_KIND_MIXED);
 		if (ch < 0)
 			return 0;
 		strbuf_addch(sb, ch);

url.c

@@ -62,7 +62,7 @@ static char *url_decode_internal(const char **query, int len,
 		}
 
 		if (c == '%' && (len < 0 || len >= 3)) {
-			int val = hex2chr(q + 1);
+			int val = hex2chr(q + 1, HEX_KIND_MIXED);
 			if (0 < val) {
 				strbuf_addch(out, val);
 				q += 3;

urlmatch.c

@@ -50,7 +50,7 @@ static int append_normalized_escapes(struct strbuf *buf,
 		if (ch == '%') {
 			if (from_len < 2)
 				return 0;
-			ch = hex2chr(from);
+			ch = hex2chr(from, HEX_KIND_MIXED);
 			if (ch < 0)
 				return 0;
 			from += 2;