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Diffstat (limited to 'src/common/crypto.c')
| -rw-r--r-- | src/common/crypto.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/src/common/crypto.c b/src/common/crypto.c index 40cb5fafae..bcb8a375a8 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -1677,6 +1677,21 @@ smartlist_choose(const smartlist_t *sl) return NULL; /* no elements to choose from */ } +/** Scramble the elements of sl into a random order. */ +void +smartlist_shuffle(smartlist_t *sl) +{ + int i; + /* From the end of the list to the front, choose at random from the + positions we haven't looked at yet, and swap that position into the + current position. Remember to give "no swap" the same probability as + any other swap. */ + for (i = smartlist_len(sl)-1; i > 0; --i) { + int j = crypto_rand_int(i+1); + smartlist_swap(sl, i, j); + } +} + /** Base-64 encode <b>srclen</b> bytes of data from <b>src</b>. Write * the result into <b>dest</b>, if it will fit within <b>destlen</b> * bytes. Return the number of bytes written on success; -1 if |