/*

 ** $Id: ltablib.c,v 1.38.1.3 2008/02/14 16:46:58 roberto Exp $

 ** Library for Table Manipulation

 ** See Copyright Notice in lua.h

 */

 

 

 #include <stddef.h>

 

 #define ltablib_c

 #define LUA_LIB

 

 #include "lua.h"

 

 #include "lauxlib.h"

 #include "lualib.h"

 

 

 #define aux_getn(L,n)	(luaL_checktype(L, n, LUA_TTABLE), luaL_getn(L, n))

 

 

 static int foreachi (lua_State *L) {

   int i;

   int n = aux_getn(L, 1);

   luaL_checktype(L, 2, LUA_TFUNCTION);

   for (i=1; i <= n; i++) {

     lua_pushvalue(L, 2);  /* function */

     lua_pushinteger(L, i);  /* 1st argument */

     lua_rawgeti(L, 1, i);  /* 2nd argument */

     lua_call(L, 2, 1);

     if (!lua_isnil(L, -1))

       return 1;

     lua_pop(L, 1);  /* remove nil result */

   }

   return 0;

 }

 

 

 static int foreach (lua_State *L) {

   luaL_checktype(L, 1, LUA_TTABLE);

   luaL_checktype(L, 2, LUA_TFUNCTION);

   lua_pushnil(L);  /* first key */

   while (lua_next(L, 1)) {

     lua_pushvalue(L, 2);  /* function */

     lua_pushvalue(L, -3);  /* key */

     lua_pushvalue(L, -3);  /* value */

     lua_call(L, 2, 1);

     if (!lua_isnil(L, -1))

       return 1;

     lua_pop(L, 2);  /* remove value and result */

   }

   return 0;

 }

 

 

 static int maxn (lua_State *L) {

   lua_Number max = 0;

   luaL_checktype(L, 1, LUA_TTABLE);

   lua_pushnil(L);  /* first key */

   while (lua_next(L, 1)) {

     lua_pop(L, 1);  /* remove value */

     if (lua_type(L, -1) == LUA_TNUMBER) {

       lua_Number v = lua_tonumber(L, -1);

       if (v > max) max = v;

     }

   }

   lua_pushnumber(L, max);

   return 1;

 }

 

 

 static int getn (lua_State *L) {

   lua_pushinteger(L, aux_getn(L, 1));

   return 1;

 }

 

 

 static int setn (lua_State *L) {

   luaL_checktype(L, 1, LUA_TTABLE);

 #ifndef luaL_setn

   luaL_setn(L, 1, luaL_checkint(L, 2));

 #else

   luaL_error(L, LUA_QL("setn") " is obsolete");

 #endif

   lua_pushvalue(L, 1);

   return 1;

 }

 

 

 static int tinsert (lua_State *L) {

   int e = aux_getn(L, 1) + 1;  /* first empty element */

   int pos;  /* where to insert new element */

   switch (lua_gettop(L)) {

     case 2: {  /* called with only 2 arguments */

       pos = e;  /* insert new element at the end */

       break;

     }

     case 3: {

       int i;

       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */

       if (pos > e) e = pos;  /* `grow' array if necessary */

       for (i = e; i > pos; i--) {  /* move up elements */

         lua_rawgeti(L, 1, i-1);

         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */

       }

       break;

     }

     default: {

       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));

     }

   }

   luaL_setn(L, 1, e);  /* new size */

   lua_rawseti(L, 1, pos);  /* t[pos] = v */

   return 0;

 }

 

 

 static int tremove (lua_State *L) {

   int e = aux_getn(L, 1);

   int pos = luaL_optint(L, 2, e);

   if (!(1 <= pos && pos <= e))  /* position is outside bounds? */

    return 0;  /* nothing to remove */

   luaL_setn(L, 1, e - 1);  /* t.n = n-1 */

   lua_rawgeti(L, 1, pos);  /* result = t[pos] */

   for ( ;pos<e; pos++) {

     lua_rawgeti(L, 1, pos+1);

     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */

   }

   lua_pushnil(L);

   lua_rawseti(L, 1, e);  /* t[e] = nil */

   return 1;

 }

 

 

 static void addfield (lua_State *L, luaL_Buffer *b, int i) {

   lua_rawgeti(L, 1, i);

   if (!lua_isstring(L, -1))

     luaL_error(L, "invalid value (%s) at index %d in table for "

                   LUA_QL("concat"), luaL_typename(L, -1), i);

     luaL_addvalue(b);

 }

 

 

 static int tconcat (lua_State *L) {

   luaL_Buffer b;

   size_t lsep;

   int i, last;

   const char *sep = luaL_optlstring(L, 2, "", &lsep);

   luaL_checktype(L, 1, LUA_TTABLE);

   i = luaL_optint(L, 3, 1);

   last = luaL_opt(L, luaL_checkint, 4, luaL_getn(L, 1));

   luaL_buffinit(L, &b);

   for (; i < last; i++) {

     addfield(L, &b, i);

     luaL_addlstring(&b, sep, lsep);

   }

   if (i == last)  /* add last value (if interval was not empty) */

     addfield(L, &b, i);

   luaL_pushresult(&b);

   return 1;

 }

 

 

 

 /*

 ** {======================================================

 ** Quicksort

 ** (based on `Algorithms in MODULA-3', Robert Sedgewick;

 **  Addison-Wesley, 1993.)

 */

 

 

 static void set2 (lua_State *L, int i, int j) {

   lua_rawseti(L, 1, i);

   lua_rawseti(L, 1, j);

 }

 

 static int sort_comp (lua_State *L, int a, int b) {

   if (!lua_isnil(L, 2)) {  /* function? */

     int res;

     lua_pushvalue(L, 2);

     lua_pushvalue(L, a-1);  /* -1 to compensate function */

     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */

     lua_call(L, 2, 1);

     res = lua_toboolean(L, -1);

     lua_pop(L, 1);

     return res;

   }

   else  /* a < b? */

     return lua_lessthan(L, a, b);

 }

 

 static void auxsort (lua_State *L, int l, int u) {

   while (l < u) {  /* for tail recursion */

     int i, j;

     /* sort elements a[l], a[(l+u)/2] and a[u] */

     lua_rawgeti(L, 1, l);

     lua_rawgeti(L, 1, u);

     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */

       set2(L, l, u);  /* swap a[l] - a[u] */

     else

       lua_pop(L, 2);

     if (u-l == 1) break;  /* only 2 elements */

     i = (l+u)/2;

     lua_rawgeti(L, 1, i);

     lua_rawgeti(L, 1, l);

     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */

       set2(L, i, l);

     else {

       lua_pop(L, 1);  /* remove a[l] */

       lua_rawgeti(L, 1, u);

       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */

         set2(L, i, u);

       else

         lua_pop(L, 2);

     }

     if (u-l == 2) break;  /* only 3 elements */

     lua_rawgeti(L, 1, i);  /* Pivot */

     lua_pushvalue(L, -1);

     lua_rawgeti(L, 1, u-1);

     set2(L, i, u-1);

     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */

     i = l; j = u-1;

     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */

       /* repeat ++i until a[i] >= P */

       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {

         if (i>u) luaL_error(L, "invalid order function for sorting");

         lua_pop(L, 1);  /* remove a[i] */

       }

       /* repeat --j until a[j] <= P */

       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {

         if (j<l) luaL_error(L, "invalid order function for sorting");

         lua_pop(L, 1);  /* remove a[j] */

       }

       if (j<i) {

         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */

         break;

       }

       set2(L, i, j);

     }

     lua_rawgeti(L, 1, u-1);

     lua_rawgeti(L, 1, i);

     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */

     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */

     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */

     if (i-l < u-i) {

       j=l; i=i-1; l=i+2;

     }

     else {

       j=i+1; i=u; u=j-2;

     }

     auxsort(L, j, i);  /* call recursively the smaller one */

   }  /* repeat the routine for the larger one */

 }

 

 static int sort (lua_State *L) {

   int n = aux_getn(L, 1);

   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */

   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */

     luaL_checktype(L, 2, LUA_TFUNCTION);

   lua_settop(L, 2);  /* make sure there is two arguments */

   auxsort(L, 1, n);

   return 0;

 }

 

 /* }====================================================== */

 

 

 static const luaL_Reg tab_funcs[] = {

   {"concat", tconcat},

   {"foreach", foreach},

   {"foreachi", foreachi},

   {"getn", getn},

   {"maxn", maxn},

   {"insert", tinsert},

   {"remove", tremove},

   {"setn", setn},

   {"sort", sort},

   {NULL, NULL}

 };

 

 

 LUALIB_API int luaopen_table (lua_State *L) {

   luaL_register(L, LUA_TABLIBNAME, tab_funcs);

   return 1;

 }