Implement character class parsing

lib/parser.c

@@ -8,6 +8,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 
+#define CLASS_START_CAPACITY 4
 #define SEQUENCE_START_CAPACITY 8
 
 static bool is_special(char c)
@@ -21,6 +22,9 @@ static bool is_special(char c)
 	case '*':
 	case '+':
 	case '?':
+	case '[':
+	case ']':
+	case '^':
 		return true;
 	default:
 		return false;
@@ -40,6 +44,48 @@ static int parse_literal(const char *input, int rem, char *out)
 	}
 }
 
+static int parse_class(const char *input, int rem, class_t *out)
+{
+	int result, used = 0;
+
+	if (used >= rem || '[' != input[used])
+		return -1;
+	++used;
+
+	if (used < rem && '^' == input[used]) {
+		out->negated = true;
+		++used;
+	}
+
+	out->count = 0;
+	out->capacity = CLASS_START_CAPACITY;
+	out->contents = malloc(out->capacity);
+	if (NULL == out->contents)
+		return -1;
+
+	while (used < rem) {
+		if (out->count >= out->capacity) {
+			out->capacity *= 2;
+			out->contents = realloc(out->contents, out->capacity);
+			if (NULL == out->contents)
+				return -1;
+		}
+
+		result = parse_literal(
+		    input + used, rem - used, &out->contents[out->count]);
+		if (result < 0)
+			break;
+		used += result;
+		++out->count;
+	}
+
+	if (used >= rem || ']' != input[used])
+		return -1;
+	++used;
+
+	return out->count > 0 ? used : -1;
+}
+
 static int parse_term(const char *input, int rem, term_t *out)
 {
 	int result, used = 0;
@@ -62,6 +108,12 @@ static int parse_term(const char *input, int rem, term_t *out)
 		if (')' != input[used])
 			return -1;
 		++used;
+	} else if ('[' == input[0]) {
+		result = parse_class(input + used, rem - used, &out->class);
+		if (result < 0)
+			return -1;
+		out->type = TERM_TYPE_CLASS;
+		used += result;
 	} else {
 		result = parse_literal(input + used, rem - used, &out->literal);
 		if (result < 0)