lua的math库是通过lua扩展而来，主要对系统math库进行了一次封装，以供lua使用，一般可以从lmathlib文件开始阅读源码。
//绝对值 static int math_abs (lua_State *L) { lua_pushnumber(L, l_mathop(fabs)(luaL_checknumber(L, 1))); return 1; } //正弦值 static int math_sin (lua_State *L) { lua_pushnumber(L, l_mathop(sin)(luaL_checknumber(L, 1))); return 1; } //双曲正弦值 static int math_sinh (lua_State *L) { lua_pushnumber(L, l_mathop(sinh)(luaL_checknumber(L, 1))); return 1; } //余弦值 static int math_cos (lua_State *L) { lua_pushnumber(L, l_mathop(cos)(luaL_checknumber(L, 1))); return 1; } //双曲余弦值 static int math_cosh (lua_State *L) { lua_pushnumber(L, l_mathop(cosh)(luaL_checknumber(L, 1))); return 1; } //正切值 static int math_tan (lua_State *L) { lua_pushnumber(L, l_mathop(tan)(luaL_checknumber(L, 1))); return 1; } //双曲正切值 static int math_tanh (lua_State *L) { lua_pushnumber(L, l_mathop(tanh)(luaL_checknumber(L, 1))); return 1; } //反正弦值 static int math_asin (lua_State *L) { lua_pushnumber(L, l_mathop(asin)(luaL_checknumber(L, 1))); return 1; } //反余弦值 static int math_acos (lua_State *L) { lua_pushnumber(L, l_mathop(acos)(luaL_checknumber(L, 1))); return 1; } //反正切值 static int math_atan (lua_State *L) { lua_pushnumber(L, l_mathop(atan)(luaL_checknumber(L, 1))); return 1; } //X-Y平面上所对应的(x,y)坐标的角度 static int math_atan2 (lua_State *L) { lua_pushnumber(L, l_mathop(atan2)(luaL_checknumber(L, 1), luaL_checknumber(L, 2))); return 1; } //向上取整，即取不小于x的最小整数 static int math_ceil (lua_State *L) { lua_pushnumber(L, l_mathop(ceil)(luaL_checknumber(L, 1))); return 1; } //向下取整,即取不大于x的最大整数 static int math_floor (lua_State *L) { lua_pushnumber(L, l_mathop(floor)(luaL_checknumber(L, 1))); return 1; } //计算x/y的余数 static int math_fmod (lua_State *L) { lua_pushnumber(L, l_mathop(fmod)(luaL_checknumber(L, 1), luaL_checknumber(L, 2))); return 1; } //分解x，以得到x的整数和小数部分 static int math_modf (lua_State *L) { lua_Number ip; lua_Number fp = l_mathop(modf)(luaL_checknumber(L, 1), &ip); lua_pushnumber(L, ip); lua_pushnumber(L, fp); return 2; } //计算平方根 static int math_sqrt (lua_State *L) { lua_pushnumber(L, l_mathop(sqrt)(luaL_checknumber(L, 1))); return 1; } //计算x的y次幂 static int math_pow (lua_State *L) { lua_Number x = luaL_checknumber(L, 1); lua_Number y = luaL_checknumber(L, 2); lua_pushnumber(L, l_mathop(pow)(x, y)); return 1; } //计算指数幂 static int math_log (lua_State *L) { lua_Number x = luaL_checknumber(L, 1); lua_Number res; if (lua_isnoneornil(L, 2)) res = l_mathop(log)(x); else { lua_Number base = luaL_checknumber(L, 2); if (base == (lua_Number)10.0) res = l_mathop(log10)(x); else res = l_mathop(log)(x)/l_mathop(log)(base); } lua_pushnumber(L, res); return 1; } #if defined(LUA_COMPAT_LOG10) static int math_log10 (lua_State *L) { lua_pushnumber(L, l_mathop(log10)(luaL_checknumber(L, 1))); return 1; } #endif //以自然常数e为底的指数函数 static int math_exp (lua_State *L) { lua_pushnumber(L, l_mathop(exp)(luaL_checknumber(L, 1))); return 1; } //将弧度转换为角度 static int math_deg (lua_State *L) { lua_pushnumber(L, luaL_checknumber(L, 1)/RADIANS_PER_DEGREE); return 1; } //将角度转换为弧度 static int math_rad (lua_State *L) { lua_pushnumber(L, luaL_checknumber(L, 1)*RADIANS_PER_DEGREE); return 1; } //把一个浮点数分解为尾数和指数 static int math_frexp (lua_State *L) { int e; lua_pushnumber(L, l_mathop(frexp)(luaL_checknumber(L, 1), &e)); lua_pushinteger(L, e); return 2; } //计算value乘以2的exp次幂 static int math_ldexp (lua_State *L) { lua_Number x = luaL_checknumber(L, 1); int ep = luaL_checkint(L, 2); lua_pushnumber(L, l_mathop(ldexp)(x, ep)); return 1; } //求最小值 static int math_min (lua_State *L) { int n = lua_gettop(L); /* number of arguments */ lua_Number dmin = luaL_checknumber(L, 1); int i; for (i=2; i<=n; i++) { lua_Number d = luaL_checknumber(L, i); if (d < dmin) dmin = d; } lua_pushnumber(L, dmin); return 1; } //求最大值 static int math_max (lua_State *L) { int n = lua_gettop(L); /* number of arguments */ lua_Number dmax = luaL_checknumber(L, 1); int i; for (i=2; i<=n; i++) { lua_Number d = luaL_checknumber(L, i); if (d > dmax) dmax = d; } lua_pushnumber(L, dmax); return 1; } //随机数 static int 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)(rand()%RAND_MAX) / (lua_Number)RAND_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 */ lua_Number u = luaL_checknumber(L, 1); luaL_argcheck(L, (lua_Number)1.0 <= u, 1, "interval is empty"); lua_pushnumber(L, l_mathop(floor)(r*u) + (lua_Number)(1.0)); /* [1, u] */ break; } case 2: { /* lower and upper limits */ lua_Number l = luaL_checknumber(L, 1); lua_Number u = luaL_checknumber(L, 2); luaL_argcheck(L, l <= u, 2, "interval is empty"); lua_pushnumber(L, l_mathop(floor)(r*(u-l+1)) + l); /* [l, u] */ break; } default: return luaL_error(L, "wrong number of arguments"); } return 1; } //设置随机种子 static int math_randomseed (lua_State *L) { srand(luaL_checkunsigned(L, 1)); (void)rand(); /* discard first value to avoid undesirable correlations */ return 0; }