Update SHA1_LENGTH -> kSHA1Length to match previous change to SHA256_LENGTH.

base/sha1.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_SHA1_H_
 #define BASE_SHA1_H_
 #pragma once
 
 #include <string>
 
 #include "base/base_export.h"
 
 namespace base {
 
-// This function performs SHA-1 operations.
+// These functions perform SHA-1 operations.
 
-enum {
-  SHA1_LENGTH = 20  // Length in bytes of a SHA-1 hash.
-};
+const size_t kSHA1Length = 20;  // Length in bytes of a SHA-1 hash.

[wtc, 2011/09/24 01:39:41]

I asked you this question before but don't remember if you
answered it.  Could you tell me again whether we should use
'static' on a constant defined in a header file?  Thanks.

[Peter Kasting, 2011/09/25 20:52:01]

This turns out to be an interesting C-vs.C++-ism.  In C, file-scope variables
with no explicit "static" or "extern" declaration default to extern linkage.  In
C++, they default to static linkage if they are "const" and extern linkage
otherwise.  So in C++, writing "static" on this const variable does not make a
difference, but in C it does (and would be necessary, since extern linkage here
would lead to multiply-defined symbols).

I have no particular feeling as to whether we should explicitly say "static"
here for clarity.  I removed it here and on kSHA256Length because I thought you
were complaining about it in the other case :)

[wtc, 2011/09/26 18:06:22]

Thank you for the explanation.  I didn't know exactly how
this works in C++, so I may have complained about it in the
other CL.  Sorry about that.

Please do what you think is right for C++.

[Peter Kasting, 2011/09/26 20:08:18]

OK.  Explicitly saying "static" is probably clearer, so I've done that.

 
 // Computes the SHA-1 hash of the input string |str| and returns the full
 // hash.
 BASE_EXPORT std::string SHA1HashString(const std::string& str);
 
 // Computes the SHA-1 hash of the |len| bytes in |data| and puts the hash
-// in |hash|. |hash| must be SHA1_LENGTH bytes long.
+// in |hash|. |hash| must be kSHA1Length bytes long.
 BASE_EXPORT void SHA1HashBytes(const unsigned char* data, size_t len,
                                unsigned char* hash);
 
 }  // namespace base
 
 #endif  // BASE_SHA1_H_