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.
19 #define ISAAC64_MASK ((uint64_t)0xFFFFFFFFFFFFFFFFULL)
21 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)
22 #if !defined(HAS_INLINE)
26 # if (defined(__GNUC__) && __GNUC__ >= 2 && !defined(inline))
27 # define inline __inline__
30 #if !defined(HAS_INLINE) && !defined(inline)
31 #define inline /*empty*/
34 /* Extract ISAAC64_SZ_LOG bits (starting at bit 3). */
35 static inline uint32_t lower_bits(uint64_t x)
37 return (x & ((ISAAC64_SZ-1) << 3)) >>3;
40 /* Extract next ISAAC64_SZ_LOG bits (starting at bit ISAAC64_SZ_LOG+2). */
41 static inline uint32_t upper_bits(uint64_t y)
43 return (y >> (ISAAC64_SZ_LOG+3)) & (ISAAC64_SZ-1);
46 static void isaac64_update(isaac64_ctx *_ctx){
57 b=_ctx->b+(++_ctx->c);
58 for(i=0;i<ISAAC64_SZ/2;i++){
60 a=~(a^a<<21)+m[i+ISAAC64_SZ/2];
61 m[i]=y=m[lower_bits(x)]+a+b;
62 r[i]=b=m[upper_bits(y)]+x;
64 a=(a^a>>5)+m[i+ISAAC64_SZ/2];
65 m[i]=y=m[lower_bits(x)]+a+b;
66 r[i]=b=m[upper_bits(y)]+x;
68 a=(a^a<<12)+m[i+ISAAC64_SZ/2];
69 m[i]=y=m[lower_bits(x)]+a+b;
70 r[i]=b=m[upper_bits(y)]+x;
72 a=(a^a>>33)+m[i+ISAAC64_SZ/2];
73 m[i]=y=m[lower_bits(x)]+a+b;
74 r[i]=b=m[upper_bits(y)]+x;
76 for(i=ISAAC64_SZ/2;i<ISAAC64_SZ;i++){
78 a=~(a^a<<21)+m[i-ISAAC64_SZ/2];
79 m[i]=y=m[lower_bits(x)]+a+b;
80 r[i]=b=m[upper_bits(y)]+x;
82 a=(a^a>>5)+m[i-ISAAC64_SZ/2];
83 m[i]=y=m[lower_bits(x)]+a+b;
84 r[i]=b=m[upper_bits(y)]+x;
86 a=(a^a<<12)+m[i-ISAAC64_SZ/2];
87 m[i]=y=m[lower_bits(x)]+a+b;
88 r[i]=b=m[upper_bits(y)]+x;
90 a=(a^a>>33)+m[i-ISAAC64_SZ/2];
91 m[i]=y=m[lower_bits(x)]+a+b;
92 r[i]=b=m[upper_bits(y)]+x;
99 static void isaac64_mix(uint64_t _x[8]){
100 static const unsigned char SHIFT[8]={9,9,23,15,14,20,17,14};
104 _x[(i+5)&7]^=_x[(i+7)&7]>>SHIFT[i];
108 _x[(i+5)&7]^=_x[(i+7)&7]<<SHIFT[i];
114 void isaac64_init(isaac64_ctx *_ctx,const unsigned char *_seed,int _nseed){
115 _ctx->a=_ctx->b=_ctx->c=0;
116 memset(_ctx->r,0,sizeof(_ctx->r));
117 isaac64_reseed(_ctx,_seed,_nseed);
120 void isaac64_reseed(isaac64_ctx *_ctx,const unsigned char *_seed,int _nseed){
128 if(_nseed>ISAAC64_SEED_SZ_MAX)_nseed=ISAAC64_SEED_SZ_MAX;
129 for(i=0;i<_nseed>>3;i++){
130 r[i]^=(uint64_t)_seed[i<<3|7]<<56|(uint64_t)_seed[i<<3|6]<<48|
131 (uint64_t)_seed[i<<3|5]<<40|(uint64_t)_seed[i<<3|4]<<32|
132 (uint64_t)_seed[i<<3|3]<<24|(uint64_t)_seed[i<<3|2]<<16|
133 (uint64_t)_seed[i<<3|1]<<8|_seed[i<<3];
139 for(j=1;j<_nseed;j++)ri|=(uint64_t)_seed[i<<3|j]<<(j<<3);
142 x[0]=x[1]=x[2]=x[3]=x[4]=x[5]=x[6]=x[7]=(uint64_t)0x9E3779B97F4A7C13ULL;
143 for(i=0;i<4;i++)isaac64_mix(x);
144 for(i=0;i<ISAAC64_SZ;i+=8){
145 for(j=0;j<8;j++)x[j]+=r[i+j];
147 memcpy(m+i,x,sizeof(x));
149 for(i=0;i<ISAAC64_SZ;i+=8){
150 for(j=0;j<8;j++)x[j]+=m[i+j];
152 memcpy(m+i,x,sizeof(x));
154 isaac64_update(_ctx);
157 uint64_t isaac64_next_uint64(isaac64_ctx *_ctx){
158 if(!_ctx->n)isaac64_update(_ctx);
159 return _ctx->r[--_ctx->n];
162 uint64_t isaac64_next_uint(isaac64_ctx *_ctx,uint64_t _n){
167 r=isaac64_next_uint64(_ctx);
171 while(((d+_n-1)&ISAAC64_MASK)<d);
174 #endif /* USE_ISAAC64 */