From 1acf8b88af11fe89e5034234ff21934107cb726d Mon Sep 17 00:00:00 2001 From: Martin Guy Date: Wed, 30 Mar 2011 12:48:24 +0200 Subject: [PATCH] :Integer mathlib for eLua ------------------------ This adds the functions of mathlib that make sense when numbers are integers: functions [abs,max,min,random,randomseed,sqrt] and constant "huge" so that idioms like this (from p.195 of Programming in Lua) also work: for i = 1,math.huge do ... if ... then break end ... end The square root gives the integer square root of positive numbers (which would be floor(sqrt(f)) in a floating point world). --- src/lua/lmathlib.c | 104 ++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 94 insertions(+), 10 deletions(-) diff --git a/src/lua/lmathlib.c b/src/lua/lmathlib.c index 88fcb432..b8731e4e 100644 --- a/src/lua/lmathlib.c +++ b/src/lua/lmathlib.c @@ -24,7 +24,13 @@ static int math_abs (lua_State *L) { +#ifdef LUA_NUMBER_INTEGRAL + lua_Number x = luaL_checknumber(L, 1); + if (x < 0) x = -x; //fails for -2^31 + lua_pushnumber(L, x); +#else lua_pushnumber(L, fabs(luaL_checknumber(L, 1))); +#endif return 1; } @@ -101,8 +107,38 @@ static int math_modf (lua_State *L) { return 2; } +#ifdef LUA_NUMBER_INTEGRAL +// Integer square root for integer version +static lua_Number isqrt(lua_Number x) +{ + lua_Number op, res, one; + + op = x; res = 0; + + /* "one" starts at the highest power of four <= than the argument. */ + one = 1 << 30; /* second-to-top bit set */ + while (one > op) one >>= 2; + + while (one != 0) { + if (op >= res + one) { + op = op - (res + one); + res = res + 2 * one; + } + res >>= 1; + one >>= 2; + } + return(res); +} +#endif + static int math_sqrt (lua_State *L) { +#ifdef LUA_NUMBER_INTEGRAL + lua_Number x = luaL_checknumber(L, 1); + luaL_argcheck(L, 0<=x, 1, "negative"); + lua_pushnumber(L, isqrt(x)); +#else lua_pushnumber(L, sqrt(luaL_checknumber(L, 1))); +#endif return 1; } @@ -178,6 +214,36 @@ static int math_max (lua_State *L) { } +#ifdef LUA_NUMBER_INTEGRAL + +static int math_random (lua_State *L) { + lua_Number r = (lua_Number)(rand()%RAND_MAX); + + switch (lua_gettop(L)) { /* check number of arguments */ + case 0: { /* no arguments */ + lua_pushnumber(L, 0); /* Number between 0 and 1 - always 0 with ints */ + break; + } + case 1: { /* only upper limit */ + int u = luaL_checkint(L, 1); + luaL_argcheck(L, 1<=u, 1, "interval is empty"); + lua_pushnumber(L, (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, (r%(u-l+1))+l); /* int between `l' and `u' */ + break; + } + default: return luaL_error(L, "wrong number of arguments"); + } + return 1; +} + +#else + 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 */ @@ -205,6 +271,8 @@ static int math_random (lua_State *L) { return 1; } +#endif + static int math_randomseed (lua_State *L) { srand(luaL_checkint(L, 1)); @@ -214,7 +282,17 @@ static int math_randomseed (lua_State *L) { #define MIN_OPT_LEVEL 1 #include "lrodefs.h" const LUA_REG_TYPE math_map[] = { -#ifndef LUA_NUMBER_INTEGRAL +#ifdef LUA_NUMBER_INTEGRAL + {LSTRKEY("abs"), LFUNCVAL(math_abs)}, + {LSTRKEY("max"), LFUNCVAL(math_max)}, + {LSTRKEY("min"), LFUNCVAL(math_min)}, + {LSTRKEY("random"), LFUNCVAL(math_random)}, + {LSTRKEY("randomseed"), LFUNCVAL(math_randomseed)}, + {LSTRKEY("sqrt"), LFUNCVAL(math_sqrt)}, +#if LUA_OPTIMIZE_MEMORY > 0 + {LSTRKEY("huge"), LNUMVAL(LONG_MAX)}, +#endif +#else {LSTRKEY("abs"), LFUNCVAL(math_abs)}, {LSTRKEY("acos"), LFUNCVAL(math_acos)}, {LSTRKEY("asin"), LFUNCVAL(math_asin)}, @@ -250,7 +328,7 @@ const LUA_REG_TYPE math_map[] = { {LSTRKEY("pi"), LNUMVAL(PI)}, {LSTRKEY("huge"), LNUMVAL(HUGE_VAL)}, #endif // #if LUA_OPTIMIZE_MEMORY > 0 -#endif // #ifndef LUA_NUMBER_INTEGRAL +#endif // #ifdef LUA_NUMBER_INTEGRAL {LNILKEY, LNILVAL} }; @@ -258,23 +336,29 @@ const LUA_REG_TYPE math_map[] = { /* ** Open math library */ + +#if defined LUA_NUMBER_INTEGRAL +# include /* for LONG_MAX */ +#endif + LUALIB_API int luaopen_math (lua_State *L) { -#if !defined LUA_NUMBER_INTEGRAL #if LUA_OPTIMIZE_MEMORY > 0 return 0; -#else // #if LUA_OPTIMIZE_MEMORY > 0 +#else luaL_register(L, LUA_MATHLIBNAME, math_map); +# if defined LUA_NUMBER_INTEGRAL + lua_pushnumber(L, LONG_MAX); + lua_setfield(L, -2, "huge"); +# else lua_pushnumber(L, PI); lua_setfield(L, -2, "pi"); lua_pushnumber(L, HUGE_VAL); lua_setfield(L, -2, "huge"); -#if defined(LUA_COMPAT_MOD) +# if defined(LUA_COMPAT_MOD) lua_getfield(L, -1, "fmod"); lua_setfield(L, -2, "mod"); -#endif // #if defined(LUA_COMPAT_MOD) +# endif +# endif return 1; -#endif // #if LUA_OPTIMIZE_MEMORY > 0 -#else // #if !defined LUA_NUMBER_INTEGRAL - return 0; -#endif // #if !defined LUA_NUMBER_INTEGRAL +#endif }