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Diffstat (limited to '')
| -rw-r--r-- | nsprpub/pr/src/misc/prlog2.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/nsprpub/pr/src/misc/prlog2.c b/nsprpub/pr/src/misc/prlog2.c new file mode 100644 index 0000000000..2d476cd711 --- /dev/null +++ b/nsprpub/pr/src/misc/prlog2.c @@ -0,0 +1,27 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "prbit.h" + +/* +** Compute the log of the least power of 2 greater than or equal to n +*/ +PR_IMPLEMENT(PRIntn) PR_CeilingLog2(PRUint32 n) +{ + PRIntn log2; + PR_CEILING_LOG2(log2, n); + return log2; +} + +/* +** Compute the log of the greatest power of 2 less than or equal to n. +** This really just finds the highest set bit in the word. +*/ +PR_IMPLEMENT(PRIntn) PR_FloorLog2(PRUint32 n) +{ + PRIntn log2; + PR_FLOOR_LOG2(log2, n); + return log2; +} |