From da3b7c31f75ab80873278e766cc219257c52673c Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Mon, 2 Nov 2009 20:12:52 +0100
Subject: [PATCH] [MINOR] tools: add hex2i() function to convert hex char to
 int

---
 include/common/standard.h |  6 ++++++
 src/standard.c            | 15 +++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/common/standard.h b/include/common/standard.h
index 544a5c315..ce3c6b85b 100644
--- a/include/common/standard.h
+++ b/include/common/standard.h
@@ -117,6 +117,12 @@ extern const char *limit_r(unsigned long n, char *buffer, int size, const char *
  */
 extern int ishex(char s);
 
+/*
+ * Return integer equivalent of character <c> for a hex digit (0-9, a-f, A-F),
+ * otherwise -1.
+ */
+extern int hex2i(int c);
+
 /*
  * Checks <name> for invalid characters. Valid chars are [A-Za-z0-9_:.-]. If an
  * invalid character is found, a pointer to it is returned. If everything is
diff --git a/src/standard.c b/src/standard.c
index 6a8724a86..aab318bb3 100644
--- a/src/standard.c
+++ b/src/standard.c
@@ -158,6 +158,21 @@ int ishex(char s)
 	return 0;
 }
 
+/*
+ * Return integer equivalent of character <c> for a hex digit (0-9, a-f, A-F),
+ * otherwise -1. This compact form helps gcc produce efficient code.
+ */
+int hex2i(int c)
+{
+	if ((unsigned char)(c -= '0') > 9) {
+		if ((unsigned char)(c -= 'A' - '0') > 5 &&
+		    (unsigned char)(c -= 'a' - 'A') > 5)
+			c = -11;
+		c += 10;
+	}
+	return c;
+}
+
 /*
  * Checks <name> for invalid characters. Valid chars are [A-Za-z0-9_:.-]. If an
  * invalid character is found, a pointer to it is returned. If everything is
-- 
2.47.3