1 /*

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

     3 ** Library for Table Manipulation

     4 ** See Copyright Notice in lua.h

     5 */

     6 

     7 

     8 #include <stddef.h>

     9 

    10 #define ltablib_c

    11 #define LUA_LIB

    12 

    13 #include "lua.h"

    14 

    15 #include "lauxlib.h"

    16 #include "lualib.h"

    17 

    18 

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

    20 

    21 

    22 static int foreachi (lua_State *L) {

    23   int i;

    24   int n = aux_getn(L, 1);

    25   luaL_checktype(L, 2, LUA_TFUNCTION);

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

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

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

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

    30     lua_call(L, 2, 1);

    31     if (!lua_isnil(L, -1))

    32       return 1;

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

    34   }

    35   return 0;

    36 }

    37 

    38 

    39 static int foreach (lua_State *L) {

    40   luaL_checktype(L, 1, LUA_TTABLE);

    41   luaL_checktype(L, 2, LUA_TFUNCTION);

    42   lua_pushnil(L);  /* first key */

    43   while (lua_next(L, 1)) {

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

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

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

    47     lua_call(L, 2, 1);

    48     if (!lua_isnil(L, -1))

    49       return 1;

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

    51   }

    52   return 0;

    53 }

    54 

    55 

    56 static int maxn (lua_State *L) {

    57   lua_Number max = 0;

    58   luaL_checktype(L, 1, LUA_TTABLE);

    59   lua_pushnil(L);  /* first key */

    60   while (lua_next(L, 1)) {

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

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

    63       lua_Number v = lua_tonumber(L, -1);

    64       if (v > max) max = v;

    65     }

    66   }

    67   lua_pushnumber(L, max);

    68   return 1;

    69 }

    70 

    71 

    72 static int getn (lua_State *L) {

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

    74   return 1;

    75 }

    76 

    77 

    78 static int setn (lua_State *L) {

    79   luaL_checktype(L, 1, LUA_TTABLE);

    80 #ifndef luaL_setn

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

    82 #else

    83   luaL_error(L, LUA_QL("setn") " is obsolete");

    84 #endif

    85   lua_pushvalue(L, 1);

    86   return 1;

    87 }

    88 

    89 

    90 static int tinsert (lua_State *L) {

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

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

    93   switch (lua_gettop(L)) {

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

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

    96       break;

    97     }

    98     case 3: {

    99       int i;

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

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

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

   103         lua_rawgeti(L, 1, i-1);

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

   105       }

   106       break;

   107     }

   108     default: {

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

   110     }

   111   }

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

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

   114   return 0;

   115 }

   116 

   117 

   118 static int tremove (lua_State *L) {

   119   int e = aux_getn(L, 1);

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

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

   122    return 0;  /* nothing to remove */

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

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

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

   126     lua_rawgeti(L, 1, pos+1);

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

   128   }

   129   lua_pushnil(L);

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

   131   return 1;

   132 }

   133 

   134 

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

   136   lua_rawgeti(L, 1, i);

   137   if (!lua_isstring(L, -1))

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

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

   140     luaL_addvalue(b);

   141 }

   142 

   143 

   144 static int tconcat (lua_State *L) {

   145   luaL_Buffer b;

   146   size_t lsep;

   147   int i, last;

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

   149   luaL_checktype(L, 1, LUA_TTABLE);

   150   i = luaL_optint(L, 3, 1);

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

   152   luaL_buffinit(L, &b);

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

   154     addfield(L, &b, i);

   155     luaL_addlstring(&b, sep, lsep);

   156   }

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

   158     addfield(L, &b, i);

   159   luaL_pushresult(&b);

   160   return 1;

   161 }

   162 

   163 

   164 

   165 /*

   166 ** {======================================================

   167 ** Quicksort

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

   169 **  Addison-Wesley, 1993.)

   170 */

   171 

   172 

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

   174   lua_rawseti(L, 1, i);

   175   lua_rawseti(L, 1, j);

   176 }

   177 

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

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

   180     int res;

   181     lua_pushvalue(L, 2);

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

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

   184     lua_call(L, 2, 1);

   185     res = lua_toboolean(L, -1);

   186     lua_pop(L, 1);

   187     return res;

   188   }

   189   else  /* a < b? */

   190     return lua_lessthan(L, a, b);

   191 }

   192 

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

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

   195     int i, j;

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

   197     lua_rawgeti(L, 1, l);

   198     lua_rawgeti(L, 1, u);

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

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

   201     else

   202       lua_pop(L, 2);

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

   204     i = (l+u)/2;

   205     lua_rawgeti(L, 1, i);

   206     lua_rawgeti(L, 1, l);

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

   208       set2(L, i, l);

   209     else {

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

   211       lua_rawgeti(L, 1, u);

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

   213         set2(L, i, u);

   214       else

   215         lua_pop(L, 2);

   216     }

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

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

   219     lua_pushvalue(L, -1);

   220     lua_rawgeti(L, 1, u-1);

   221     set2(L, i, u-1);

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

   223     i = l; j = u-1;

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

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

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

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

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

   229       }

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

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

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

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

   234       }

   235       if (j<i) {

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

   237         break;

   238       }

   239       set2(L, i, j);

   240     }

   241     lua_rawgeti(L, 1, u-1);

   242     lua_rawgeti(L, 1, i);

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

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

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

   246     if (i-l < u-i) {

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

   248     }

   249     else {

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

   251     }

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

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

   254 }

   255 

   256 static int sort (lua_State *L) {

   257   int n = aux_getn(L, 1);

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

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

   260     luaL_checktype(L, 2, LUA_TFUNCTION);

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

   262   auxsort(L, 1, n);

   263   return 0;

   264 }

   265 

   266 /* }====================================================== */

   267 

   268 

   269 static const luaL_Reg tab_funcs[] = {

   270   {"concat", tconcat},

   271   {"foreach", foreach},

   272   {"foreachi", foreachi},

   273   {"getn", getn},

   274   {"maxn", maxn},

   275   {"insert", tinsert},

   276   {"remove", tremove},

   277   {"setn", setn},

   278   {"sort", sort},

   279   {NULL, NULL}

   280 };

   281 

   282 

   283 LUALIB_API int luaopen_table (lua_State *L) {

   284   luaL_register(L, LUA_TABLIBNAME, tab_funcs);

   285   return 1;

   286 }

   287