Add is_regex_special()

Add is_regex_special(), a character class macro for chars that have a
special meaning in regular expressions.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ctype.c

@@ -10,16 +10,17 @@ enum {
 	A = GIT_ALPHA,
 	D = GIT_DIGIT,
 	G = GIT_GLOB_SPECIAL,	/* *, ?, [, \\ */
+	R = GIT_REGEX_SPECIAL,	/* $, (, ), +, ., ^, {, | * */
 };
 
 unsigned char sane_ctype[256] = {
 	0, 0, 0, 0, 0, 0, 0, 0, 0, S, S, 0, 0, S, 0, 0,		/*   0.. 15 */
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,		/*  16.. 31 */
-	S, 0, 0, 0, 0, 0, 0, 0, 0, 0, G, 0, 0, 0, 0, 0,		/*  32.. 47 */
+	S, 0, 0, 0, R, 0, 0, 0, R, R, G, R, 0, 0, R, 0,		/*  32.. 47 */
 	D, D, D, D, D, D, D, D, D, D, 0, 0, 0, 0, 0, G,		/*  48.. 63 */
 	0, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,		/*  64.. 79 */
-	A, A, A, A, A, A, A, A, A, A, A, G, G, 0, 0, 0,		/*  80.. 95 */
+	A, A, A, A, A, A, A, A, A, A, A, G, G, 0, R, 0,		/*  80.. 95 */
 	0, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,		/*  96..111 */
-	A, A, A, A, A, A, A, A, A, A, A, 0, 0, 0, 0, 0,		/* 112..127 */
+	A, A, A, A, A, A, A, A, A, A, A, R, R, 0, 0, 0,		/* 112..127 */
 	/* Nothing in the 128.. range */
 };

git-compat-util.h

@@ -328,12 +328,14 @@ extern unsigned char sane_ctype[256];
 #define GIT_DIGIT 0x02
 #define GIT_ALPHA 0x04
 #define GIT_GLOB_SPECIAL 0x08
+#define GIT_REGEX_SPECIAL 0x10
 #define sane_istest(x,mask) ((sane_ctype[(unsigned char)(x)] & (mask)) != 0)
 #define isspace(x) sane_istest(x,GIT_SPACE)
 #define isdigit(x) sane_istest(x,GIT_DIGIT)
 #define isalpha(x) sane_istest(x,GIT_ALPHA)
 #define isalnum(x) sane_istest(x,GIT_ALPHA | GIT_DIGIT)
 #define is_glob_special(x) sane_istest(x,GIT_GLOB_SPECIAL)
+#define is_regex_special(x) sane_istest(x,GIT_GLOB_SPECIAL | GIT_REGEX_SPECIAL)
 #define tolower(x) sane_case((unsigned char)(x), 0x20)
 #define toupper(x) sane_case((unsigned char)(x), 0)
 

grep.c

@@ -28,16 +28,9 @@ void append_grep_pattern(struct grep_opt *opt, const char *pat,
 	p->next = NULL;
 }
 
-static int isregexspecial(int c)
-{
-	return c == '\0' || is_glob_special(c) ||
-		c == '$' || c == '(' || c == ')' || c == '+' ||
-		c == '.' || c == '^' || c == '{' || c == '|';
-}
-
 static int is_fixed(const char *s)
 {
-	while (!isregexspecial(*s))
+	while (*s && !is_regex_special(*s))
 		s++;
 	return !*s;
 }

test-ctype.c

@@ -26,6 +26,11 @@ static int test_is_glob_special(int c)
 	return is_glob_special(c);
 }
 
+static int test_is_regex_special(int c)
+{
+	return is_regex_special(c);
+}
+
 #define DIGIT "0123456789"
 #define LOWER "abcdefghijklmnopqrstuvwxyz"
 #define UPPER "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
@@ -40,6 +45,7 @@ static const struct ctype_class {
 	{ "isalpha", test_isalpha, LOWER UPPER },
 	{ "isalnum", test_isalnum, LOWER UPPER DIGIT },
 	{ "is_glob_special", test_is_glob_special, "*?[\\" },
+	{ "is_regex_special", test_is_regex_special, "$()*+.?[\\^{|" },
 	{ NULL }
 };