Function redis_math_random

src/scripting.cpp:1364–1390

The following implementation is the one shipped with Lua itself but with * rand() replaced by redisLrand48(). */

/* The following implementation is the one shipped with Lua itself but with
 * rand() replaced by redisLrand48(). */
int redis_math_random (lua_State *L) {
  /* the `%' avoids the (rare) case of r==1, and is needed also because on
     some systems (SunOS!) `rand()' may return a value larger than RAND_MAX */
  lua_Number r = (lua_Number)(redisLrand48()%REDIS_LRAND48_MAX) /
                                (lua_Number)REDIS_LRAND48_MAX;
  switch (lua_gettop(L)) {  /* check number of arguments */
    case 0: {  /* no arguments */
      lua_pushnumber(L, r);  /* Number between 0 and 1 */
      break;
    }
    case 1: {  /* only upper limit */
      int u = luaL_checkint(L, 1);
      luaL_argcheck(L, 1<=u, 1, "interval is empty");
      lua_pushnumber(L, floor(r*u)+1);  /* int between 1 and `u' */
      break;
    }
    case 2: {  /* lower and upper limits */
      int l = luaL_checkint(L, 1);
      int u = luaL_checkint(L, 2);
      luaL_argcheck(L, l<=u, 2, "interval is empty");
      lua_pushnumber(L, floor(r*(u-l+1))+l);  /* int between `l' and `u' */
      break;
    }
    default: return luaL_error(L, "wrong number of arguments");
  }
  return 1;
}

int redis_math_randomseed (lua_State *L) {
  redisSrand48(luaL_checkint(L, 1));