dtc: Refactor character literal parsing code

Move the parsing of hex, octal and escaped characters from data.c
to util.c where it can be used for character literal parsing within
strings as well as for stand alone C style character literals.

Signed-off-by: Anton Staaf <robotboy@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>

data.c

@@ -68,40 +68,6 @@ struct data data_copy_mem(const char *mem, int len)
 	return d;
 }
 
-static char get_oct_char(const char *s, int *i)
-{
-	char x[4];
-	char *endx;
-	long val;
-
-	x[3] = '\0';
-	strncpy(x, s + *i, 3);
-
-	val = strtol(x, &endx, 8);
-
-	assert(endx > x);
-
-	(*i) += endx - x;
-	return val;
-}
-
-static char get_hex_char(const char *s, int *i)
-{
-	char x[3];
-	char *endx;
-	long val;
-
-	x[2] = '\0';
-	strncpy(x, s + *i, 2);
-
-	val = strtol(x, &endx, 16);
-	if (!(endx  > x))
-		die("\\x used with no following hex digits\n");
-
-	(*i) += endx - x;
-	return val;
-}
-
 struct data data_copy_escape_string(const char *s, int len)
 {
 	int i = 0;
@@ -114,53 +80,10 @@ struct data data_copy_escape_string(const char *s, int len)
 	while (i < len) {
 		char c = s[i++];
 
-		if (c != '\\') {
-			q[d.len++] = c;
-			continue;
-		}
+		if (c == '\\')
+			c = get_escape_char(s, &i);
 
-		c = s[i++];
-		assert(c);
-		switch (c) {
-		case 'a':
-			q[d.len++] = '\a';
-			break;
-		case 'b':
-			q[d.len++] = '\b';
-			break;
-		case 't':
-			q[d.len++] = '\t';
-			break;
-		case 'n':
-			q[d.len++] = '\n';
-			break;
-		case 'v':
-			q[d.len++] = '\v';
-			break;
-		case 'f':
-			q[d.len++] = '\f';
-			break;
-		case 'r':
-			q[d.len++] = '\r';
-			break;
-		case '0':
-		case '1':
-		case '2':
-		case '3':
-		case '4':
-		case '5':
-		case '6':
-		case '7':
-			i--; /* need to re-read the first digit as
-			      * part of the octal value */
-			q[d.len++] = get_oct_char(s, &i);
-			break;
-		case 'x':
-			q[d.len++] = get_hex_char(s, &i);
-			break;
-		default:
-			q[d.len++] = c;
-		}
+		q[d.len++] = c;
 	}
 
 	q[d.len++] = '\0';

util.c

@@ -25,6 +25,7 @@
 #include <stdlib.h>
 #include <stdarg.h>
 #include <string.h>
+#include <assert.h>
 
 #include "util.h"
 
@@ -85,3 +86,101 @@ int util_is_printable_string(const void *data, int len)
 
 	return 1;
 }
+
+/*
+ * Parse a octal encoded character starting at index i in string s.  The
+ * resulting character will be returned and the index i will be updated to
+ * point at the character directly after the end of the encoding, this may be
+ * the '\0' terminator of the string.
+ */
+static char get_oct_char(const char *s, int *i)
+{
+	char x[4];
+	char *endx;
+	long val;
+
+	x[3] = '\0';
+	strncpy(x, s + *i, 3);
+
+	val = strtol(x, &endx, 8);
+
+	assert(endx > x);
+
+	(*i) += endx - x;
+	return val;
+}
+
+/*
+ * Parse a hexadecimal encoded character starting at index i in string s.  The
+ * resulting character will be returned and the index i will be updated to
+ * point at the character directly after the end of the encoding, this may be
+ * the '\0' terminator of the string.
+ */
+static char get_hex_char(const char *s, int *i)
+{
+	char x[3];
+	char *endx;
+	long val;
+
+	x[2] = '\0';
+	strncpy(x, s + *i, 2);
+
+	val = strtol(x, &endx, 16);
+	if (!(endx  > x))
+		die("\\x used with no following hex digits\n");
+
+	(*i) += endx - x;
+	return val;
+}
+
+char get_escape_char(const char *s, int *i)
+{
+	char	c = s[*i];
+	int	j = *i + 1;
+	char	val;
+
+	assert(c);
+	switch (c) {
+	case 'a':
+		val = '\a';
+		break;
+	case 'b':
+		val = '\b';
+		break;
+	case 't':
+		val = '\t';
+		break;
+	case 'n':
+		val = '\n';
+		break;
+	case 'v':
+		val = '\v';
+		break;
+	case 'f':
+		val = '\f';
+		break;
+	case 'r':
+		val = '\r';
+		break;
+	case '0':
+	case '1':
+	case '2':
+	case '3':
+	case '4':
+	case '5':
+	case '6':
+	case '7':
+		j--; /* need to re-read the first digit as
+		      * part of the octal value */
+		val = get_oct_char(s, &j);
+		break;
+	case 'x':
+		val = get_hex_char(s, &j);
+		break;
+	default:
+		val = c;
+	}
+
+	(*i) = j;
+	return val;
+}

util.h

@@ -64,4 +64,12 @@ extern char *join_path(const char *path, const char *name);
  * @return 1 if a valid printable string, 0 if not */
 int util_is_printable_string(const void *data, int len);
 
+/*
+ * Parse an escaped character starting at index i in string s.  The resulting
+ * character will be returned and the index i will be updated to point at the
+ * character directly after the end of the encoding, this may be the '\0'
+ * terminator of the string.
+ */
+char get_escape_char(const char *s, int *i);
+
 #endif /* _UTIL_H */