From e7f1bf58e44a3449ba6dcf637a51191006bd2324 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@nicira.com>
Date: Wed, 4 Nov 2009 15:12:54 -0800
Subject: [PATCH] sha1: Add functions, macros for converting digests to and
 from strings.

These will be used in the upcoming OVSDB.

The SHA1_FMT and SHA1_ARGS macros are arguably absurd, but they are
also convenient.
---
 lib/sha1.c | 31 +++++++++++++++++++++++++++++++
 lib/sha1.h | 19 +++++++++++++++++--
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/lib/sha1.c b/lib/sha1.c
index f73f2d64..205b82fe 100644
--- a/lib/sha1.c
+++ b/lib/sha1.c
@@ -31,7 +31,9 @@
 
 #include <config.h>
 #include "sha1.h"
+#include <ctype.h>
 #include <string.h>
+#include "util.h"
 
 /* a bit faster & bigger, if defined */
 #define UNROLL_LOOPS
@@ -279,3 +281,32 @@ sha1_bytes(const void *data, size_t n, uint8_t digest[SHA1_DIGEST_SIZE])
     sha1_update(&ctx, data, n);
     sha1_final(&ctx, digest);
 }
+
+void
+sha1_to_hex(const uint8_t digest[SHA1_DIGEST_SIZE],
+            char hex[SHA1_HEX_DIGEST_LEN + 1])
+{
+    int i;
+
+    for (i = 0; i < SHA1_DIGEST_SIZE; i++) {
+        *hex++ = "0123456789abcdef"[digest[i] >> 4];
+        *hex++ = "0123456789abcdef"[digest[i] & 15];
+    }
+    *hex = '\0';
+}
+
+bool
+sha1_from_hex(uint8_t digest[SHA1_DIGEST_SIZE], const char *hex)
+{
+    int i;
+
+    for (i = 0; i < SHA1_DIGEST_SIZE; i++) {
+        if (!isxdigit(hex[0]) || !isxdigit(hex[1])) {
+            return false;
+        }
+        digest[i] = (hexit_value(hex[0]) << 4) | hexit_value(hex[1]);
+        hex += 2;
+    }
+    return true;
+}
+
diff --git a/lib/sha1.h b/lib/sha1.h
index 75d3533d..9a372775 100644
--- a/lib/sha1.h
+++ b/lib/sha1.h
@@ -29,11 +29,12 @@
 #ifndef SHA1_H
 #define SHA1_H
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 
-/* Size of the SHA1 digest. */
-#define SHA1_DIGEST_SIZE 20
+#define SHA1_DIGEST_SIZE 20     /* Size of the SHA1 digest. */
+#define SHA1_HEX_DIGEST_LEN 40  /* Length of SHA1 digest as hex in ASCII. */
 
 /* SHA1 context structure. */
 struct sha1_ctx {
@@ -48,4 +49,18 @@ void sha1_update(struct sha1_ctx *, const void *, size_t);
 void sha1_final(struct sha1_ctx *, uint8_t digest[SHA1_DIGEST_SIZE]);
 void sha1_bytes(const void *, size_t, uint8_t digest[SHA1_DIGEST_SIZE]);
 
+#define SHA1_FMT \
+        "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x" \
+        "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x"
+#define SHA1_ARGS(DIGEST) \
+    ((DIGEST)[0]), ((DIGEST)[1]), ((DIGEST)[2]), ((DIGEST)[3]), \
+    ((DIGEST)[4]), ((DIGEST)[5]), ((DIGEST)[6]), ((DIGEST)[7]), \
+    ((DIGEST)[8]), ((DIGEST)[9]), ((DIGEST)[10]), ((DIGEST)[11]), \
+    ((DIGEST)[12]), ((DIGEST)[13]), ((DIGEST)[14]), ((DIGEST)[15]), \
+    ((DIGEST)[16]), ((DIGEST)[17]), ((DIGEST)[18]), ((DIGEST)[19])
+
+void sha1_to_hex(const uint8_t digest[SHA1_DIGEST_SIZE],
+                 char hex[SHA1_HEX_DIGEST_LEN + 1]);
+bool sha1_from_hex(uint8_t digest[SHA1_DIGEST_SIZE], const char *hex);
+
 #endif  /* sha1.h */
-- 
2.30.2