--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/mac/hmac/hmac_file.c	Fri May 06 13:23:02 2005 +0000
@@ -0,0 +1,89 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://libtomcrypt.org
+ */
+#include "tomcrypt.h"
+
+/**
+  @file hmac_file.c
+  HMAC support, process a file, Tom St Denis/Dobes Vandermeer
+*/
+
+#ifdef HMAC
+
+/**
+  HMAC a file
+  @param hash     The index of the hash you wish to use
+  @param fname    The name of the file you wish to HMAC
+  @param key      The secret key
+  @param keylen   The length of the secret key
+  @param out      [out] The HMAC authentication tag
+  @param outlen   [in/out]  The max size and resulting size of the authentication tag
+  @return CRYPT_OK if successful, CRYPT_NOP if file support has been disabled
+*/
+int hmac_file(int hash, const char *fname, 
+              const unsigned char *key, unsigned long keylen, 
+                    unsigned char *out, unsigned long *outlen)
+{
+#ifdef LTC_NO_FILE
+    return CRYPT_NOP;
+#else
+   hmac_state hmac;
+   FILE *in;
+   unsigned char buf[512];
+   size_t x;
+   int err;
+
+   LTC_ARGCHK(fname  != NULL);
+   LTC_ARGCHK(key    != NULL);
+   LTC_ARGCHK(out    != NULL);
+   LTC_ARGCHK(outlen != NULL);
+   
+   if((err = hash_is_valid(hash)) != CRYPT_OK) {
+       return err;
+   }
+
+   if ((err = hmac_init(&hmac, hash, key, keylen)) != CRYPT_OK) {
+       return err;
+   }
+
+   in = fopen(fname, "rb");
+   if (in == NULL) {
+      return CRYPT_FILE_NOTFOUND;
+   }
+
+   /* process the file contents */
+   do {
+      x = fread(buf, 1, sizeof(buf), in);
+      if ((err = hmac_process(&hmac, buf, (unsigned long)x)) != CRYPT_OK) {
+         /* we don't trap this error since we're already returning an error! */
+         fclose(in);
+         return err;
+      }
+   } while (x == sizeof(buf));
+
+   if (fclose(in) != 0) {
+      return CRYPT_ERROR;
+   }
+
+   /* get final hmac */
+   if ((err = hmac_done(&hmac, out, outlen)) != CRYPT_OK) {
+      return err;
+   }
+
+#ifdef LTC_CLEAN_STACK
+   /* clear memory */
+   zeromem(buf, sizeof(buf));
+#endif   
+   return CRYPT_OK;
+#endif
+}
+
+#endif
+