void isaac_reseed(isaac_ctx *_ctx,const unsigned char *_seed,int _nseed){
uint32_t *m;
uint32_t *r;
uint32_t x[8];
int i;
int j;
m=_ctx->m;
r=_ctx->r;
if(_nseed>ISAAC_SEED_SZ_MAX)_nseed=ISAAC_SEED_SZ_MAX;
for(i=0;i<_nseed>>2;i++){
r[i]^=(uint32_t)_seed[i<<2|3]<<24|(uint32_t)_seed[i<<2|2]<<16|
(uint32_t)_seed[i<<2|1]<<8|_seed[i<<2];
}
_nseed-=i<<2;
if(_nseed>0){
uint32_t ri;
ri=_seed[i<<2];
for(j=1;j<_nseed;j++)ri|=(uint32_t)_seed[i<<2|j]<<(j<<3);
r[i++]^=ri;
}
x[0]=x[1]=x[2]=x[3]=x[4]=x[5]=x[6]=x[7]=0x9E3779B9U;
for(i=0;i<4;i++)isaac_mix(x);
for(i=0;i<ISAAC_SZ;i+=8){
for(j=0;j<8;j++)x[j]+=r[i+j];
isaac_mix(x);
memcpy(m+i,x,sizeof(x));
}
for(i=0;i<ISAAC_SZ;i+=8){
for(j=0;j<8;j++)x[j]+=m[i+j];
isaac_mix(x);
memcpy(m+i,x,sizeof(x));
}
isaac_update(_ctx);
}
/**
* Seed pseudorandom sequence.
*
* @param ctx ISAAC context
* @param seed Seed buffer
* @param n Seed length
*
* @return void
*/
void isaac_seed(isaac_ctx_t *ctx, const uint8_t *seed, size_t n) {
uint32_t a, b, c, d, e, f, g, h, *m, *r;
int i;
memset(ctx, 0, sizeof(isaac_ctx_t));
memcpy(ctx->r, seed, n);
m = ctx->m;
r = ctx->r;
a = b = c = d = e = f = g = h = 0x9e3779b9;
for (i = 0; i < 4; i++)
mix(a, b, c, d, e, f, g, h);
for (i = 0; i < ISAAC_SIZE; i += 8) {
a += r[i ]; b += r[i + 1]; c += r[i + 2]; d += r[i + 3];
e += r[i + 4]; f += r[i + 5]; g += r[i + 6]; h += r[i + 7];
mix(a, b, c, d, e, f, g, h);
m[i ] = a; m[i + 1] = b; m[i + 2] = c; m[i + 3] = d;
m[i + 4] = e; m[i + 5] = f; m[i + 6] = g; m[i + 7] = h;
}
for (i = 0; i < ISAAC_SIZE; i += 8) {
a += m[i ]; b += m[i + 1]; c += m[i + 2]; d += m[i + 3];
e += m[i + 4]; f += m[i + 5]; g += m[i + 6]; h += m[i + 7];
mix(a, b, c, d, e, f, g, h);
m[i ] = a; m[i + 1] = b; m[i + 2] = c; m[i + 3] = d;
m[i + 4] = e; m[i + 5] = f; m[i + 6] = g; m[i + 7] = h;
}
isaac_update(ctx);
}
/**
* Generate 32-bit pseudorandom integer.
*
* @param ctx ISAAC context
*
* @return 32-bit pseudorandom integer
*/
uint32_t isaac_rand(isaac_ctx_t *ctx) {
if (ctx->n == 0)
isaac_update(ctx);
return ctx->r[--ctx->n];
}
uint32_t isaac_next_uint32(isaac_ctx *_ctx){
if(!_ctx->n)isaac_update(_ctx);
return _ctx->r[--_ctx->n];
}