1 /*Written by Timothy B. Terriberry (tterribe@xiph.org) 1999-2009
2 CC0 (Public domain) - see http://creativecommons.org/publicdomain/zero/1.0/
4 Based on the public domain ISAAC implementation by Robert J. Jenkins Jr.*/
9 * skip rest of file if USE_ISAAC64 isn't defined there;
10 * re-do 'inline' handling.
18 #define ISAAC64_MASK ((uint64_t)0xFFFFFFFFFFFFFFFFULL)
20 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)
21 #if !defined(HAS_INLINE)
25 # if (defined(__GNUC__) && __GNUC__ >= 2 && !defined(inline))
26 # define inline __inline__
29 #if !defined(HAS_INLINE) && !defined(inline)
30 #define inline /*empty*/
33 /* Extract ISAAC64_SZ_LOG bits (starting at bit 3). */
34 static inline uint32_t lower_bits(uint64_t x)
36 return (x & ((ISAAC64_SZ-1) << 3)) >>3;
39 /* Extract next ISAAC64_SZ_LOG bits (starting at bit ISAAC64_SZ_LOG+2). */
40 static inline uint32_t upper_bits(uint64_t y)
42 return (y >> (ISAAC64_SZ_LOG+3)) & (ISAAC64_SZ-1);
45 static void isaac64_update(isaac64_ctx *_ctx){
56 b=_ctx->b+(++_ctx->c);
57 for(i=0;i<ISAAC64_SZ/2;i++){
59 a=~(a^a<<21)+m[i+ISAAC64_SZ/2];
60 m[i]=y=m[lower_bits(x)]+a+b;
61 r[i]=b=m[upper_bits(y)]+x;
63 a=(a^a>>5)+m[i+ISAAC64_SZ/2];
64 m[i]=y=m[lower_bits(x)]+a+b;
65 r[i]=b=m[upper_bits(y)]+x;
67 a=(a^a<<12)+m[i+ISAAC64_SZ/2];
68 m[i]=y=m[lower_bits(x)]+a+b;
69 r[i]=b=m[upper_bits(y)]+x;
71 a=(a^a>>33)+m[i+ISAAC64_SZ/2];
72 m[i]=y=m[lower_bits(x)]+a+b;
73 r[i]=b=m[upper_bits(y)]+x;
75 for(i=ISAAC64_SZ/2;i<ISAAC64_SZ;i++){
77 a=~(a^a<<21)+m[i-ISAAC64_SZ/2];
78 m[i]=y=m[lower_bits(x)]+a+b;
79 r[i]=b=m[upper_bits(y)]+x;
81 a=(a^a>>5)+m[i-ISAAC64_SZ/2];
82 m[i]=y=m[lower_bits(x)]+a+b;
83 r[i]=b=m[upper_bits(y)]+x;
85 a=(a^a<<12)+m[i-ISAAC64_SZ/2];
86 m[i]=y=m[lower_bits(x)]+a+b;
87 r[i]=b=m[upper_bits(y)]+x;
89 a=(a^a>>33)+m[i-ISAAC64_SZ/2];
90 m[i]=y=m[lower_bits(x)]+a+b;
91 r[i]=b=m[upper_bits(y)]+x;
98 static void isaac64_mix(uint64_t _x[8]){
99 static const unsigned char SHIFT[8]={9,9,23,15,14,20,17,14};
103 _x[(i+5)&7]^=_x[(i+7)&7]>>SHIFT[i];
107 _x[(i+5)&7]^=_x[(i+7)&7]<<SHIFT[i];
113 void isaac64_init(isaac64_ctx *_ctx,const unsigned char *_seed,int _nseed){
114 _ctx->a=_ctx->b=_ctx->c=0;
115 memset(_ctx->r,0,sizeof(_ctx->r));
116 isaac64_reseed(_ctx,_seed,_nseed);
119 void isaac64_reseed(isaac64_ctx *_ctx,const unsigned char *_seed,int _nseed){
127 if(_nseed>ISAAC64_SEED_SZ_MAX)_nseed=ISAAC64_SEED_SZ_MAX;
128 for(i=0;i<_nseed>>3;i++){
129 r[i]^=(uint64_t)_seed[i<<3|7]<<56|(uint64_t)_seed[i<<3|6]<<48|
130 (uint64_t)_seed[i<<3|5]<<40|(uint64_t)_seed[i<<3|4]<<32|
131 (uint64_t)_seed[i<<3|3]<<24|(uint64_t)_seed[i<<3|2]<<16|
132 (uint64_t)_seed[i<<3|1]<<8|_seed[i<<3];
138 for(j=1;j<_nseed;j++)ri|=(uint64_t)_seed[i<<3|j]<<(j<<3);
141 x[0]=x[1]=x[2]=x[3]=x[4]=x[5]=x[6]=x[7]=(uint64_t)0x9E3779B97F4A7C13ULL;
142 for(i=0;i<4;i++)isaac64_mix(x);
143 for(i=0;i<ISAAC64_SZ;i+=8){
144 for(j=0;j<8;j++)x[j]+=r[i+j];
146 memcpy(m+i,x,sizeof(x));
148 for(i=0;i<ISAAC64_SZ;i+=8){
149 for(j=0;j<8;j++)x[j]+=m[i+j];
151 memcpy(m+i,x,sizeof(x));
153 isaac64_update(_ctx);
156 uint64_t isaac64_next_uint64(isaac64_ctx *_ctx){
157 if(!_ctx->n)isaac64_update(_ctx);
158 return _ctx->r[--_ctx->n];
161 uint64_t isaac64_next_uint(isaac64_ctx *_ctx,uint64_t _n){
166 r=isaac64_next_uint64(_ctx);
170 while(((d+_n-1)&ISAAC64_MASK)<d);
173 #endif /* USE_ISAAC64 */