OSX/libsecurity_cryptkit/lib/NSRandomNumberGenerator.m

   1 /* Copyright (c) 1998,2011,2014 Apple Inc.  All Rights Reserved.
   2  *
   3  * NOTICE: USE OF THE MATERIALS ACCOMPANYING THIS NOTICE IS SUBJECT
   4  * TO THE TERMS OF THE SIGNED "FAST ELLIPTIC ENCRYPTION (FEE) REFERENCE
   5  * SOURCE CODE EVALUATION AGREEMENT" BETWEEN APPLE, INC. AND THE
   6  * ORIGINAL LICENSEE THAT OBTAINED THESE MATERIALS FROM APPLE,
   7  * INC.  ANY USE OF THESE MATERIALS NOT PERMITTED BY SUCH AGREEMENT WILL
   8  * EXPOSE YOU TO LIABILITY.
   9  ***************************************************************************
  10  *
  11  * NSRandomNumberGenerator.m
  12  *
  13  * Revision History
  14  * ----------------
  15  * 28 Mar 97 at Apple
  16  *      Rewrote using feeRandom module.
  17  * ??     96    Blaine Garst at NeXT
  18  *      Created.
  19  */
  20
  21 /*
  22  * Note: out _priv ivar is actually a feeRand pointer.
  23  */
  24
  25 #import <Foundation/Foundation.h>
  26 #import "NSRandomNumberGenerator.h"
  27 #import "feeRandom.h"
  28 #import "falloc.h"
  29
  30 @implementation NSRandomNumberGenerator
  31
  32 - init
  33 {
  34         if(_priv == NULL) {
  35                 _priv = feeRandAlloc();
  36         }
  37         /*
  38          * else no need to re-init
  39          */
  40         return self;
  41 }
  42
  43 - initWithSeed:(unsigned)seed
  44 {
  45         if(_priv != NULL) {
  46                 /*
  47                  * Free & re-init to use new seed
  48                  */
  49                 feeRandFree(_priv);
  50         }
  51         _priv = feeRandAllocWithSeed(seed);
  52         return self;
  53 }
  54
  55 - (unsigned)nextNumber
  56 {
  57         if(_priv == NULL) {
  58                 return 0;
  59         }
  60         return feeRandNextNum(_priv);
  61 }
  62
  63 - (unsigned)nextNumberInRange:(NSRange)range
  64 {
  65         if(_priv == NULL) {
  66                 return 0;
  67         }
  68         return range.location + ([self nextNumber] % range.length);
  69 }
  70
  71 - (NSData *)randomDataWithLength:(unsigned)l
  72 {
  73         unsigned char *cp;
  74
  75         if(_priv == NULL) {
  76                 return nil;
  77         }
  78         cp = fmalloc(l);
  79         feeRandBytes(_priv, cp, l);
  80         return [NSData dataWithBytesNoCopy:cp length:l];
  81 }
  82
  83 @end