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view nspr/pr/include/prrng.h @ 4:b513267f632f tip
Build DBM module
author | Andre Heinecke <andre.heinecke@intevation.de> |
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date | Tue, 05 Aug 2014 18:58:03 +0200 |
parents | 1e5118fa0cb1 |
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/* -*- 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/. */ /* ** prrng.h -- NSPR Random Number Generator ** ** ** lth. 29-Oct-1999. */ #ifndef prrng_h___ #define prrng_h___ #include "prtypes.h" PR_BEGIN_EXTERN_C /* ** PR_GetRandomNoise() -- Get random noise from the host platform ** ** Description: ** PR_GetRandomNoise() provides, depending on platform, a random value. ** The length of the random value is dependent on platform and the ** platform's ability to provide a random value at that moment. ** ** The intent of PR_GetRandomNoise() is to provide a "seed" value for a ** another random number generator that may be suitable for ** cryptographic operations. This implies that the random value ** provided may not be, by itself, cryptographically secure. The value ** generated by PR_GetRandomNoise() is at best, extremely difficult to ** predict and is as non-deterministic as the underlying platfrom can ** provide. ** ** Inputs: ** buf -- pointer to a caller supplied buffer to contain the ** generated random number. buf must be at least as large as ** is specified in the 'size' argument. ** ** size -- the requested size of the generated random number ** ** Outputs: ** a random number provided in 'buf'. ** ** Returns: ** PRSize value equal to the size of the random number actually ** generated, or zero. The generated size may be less than the size ** requested. A return value of zero means that PR_GetRandomNoise() is ** not implemented on this platform, or there is no available noise ** available to be returned at the time of the call. ** ** Restrictions: ** Calls to PR_GetRandomNoise() may use a lot of CPU on some platforms. ** Some platforms may block for up to a few seconds while they ** accumulate some noise. Busy machines generate lots of noise, but ** care is advised when using PR_GetRandomNoise() frequently in your ** application. ** ** History: ** Parts of the model dependent implementation for PR_GetRandomNoise() ** were taken in whole or part from code previously in Netscape's NSS ** component. ** */ NSPR_API(PRSize) PR_GetRandomNoise( void *buf, PRSize size ); PR_END_EXTERN_C #endif /* prrng_h___ */ /* end prrng.h */