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  1. /*
  2. ** $Id: ltablib.c,v 1.63 2011/11/28 17:26:30 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)  \
  20.         (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n))
  21.  
  22.  
  23. #if defined(LUA_COMPAT_MAXN)
  24. static int maxn (lua_State *L) {
  25.   lua_Number max = 0;
  26.   luaL_checktype(L, 1, LUA_TTABLE);
  27.   lua_pushnil(L);  /* first key */
  28.   while (lua_next(L, 1)) {
  29.     lua_pop(L, 1);  /* remove value */
  30.     if (lua_type(L, -1) == LUA_TNUMBER) {
  31.       lua_Number v = lua_tonumber(L, -1);
  32.       if (v > max) max = v;
  33.     }
  34.   }
  35.   lua_pushnumber(L, max);
  36.   return 1;
  37. }
  38. #endif
  39.  
  40.  
  41. static int tinsert (lua_State *L) {
  42.   int e = aux_getn(L, 1) + 1;  /* first empty element */
  43.   int pos;  /* where to insert new element */
  44.   switch (lua_gettop(L)) {
  45.     case 2: {  /* called with only 2 arguments */
  46.       pos = e;  /* insert new element at the end */
  47.       break;
  48.     }
  49.     case 3: {
  50.       int i;
  51.       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
  52.       if (pos > e) e = pos;  /* `grow' array if necessary */
  53.       for (i = e; i > pos; i--) {  /* move up elements */
  54.         lua_rawgeti(L, 1, i-1);
  55.         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
  56.       }
  57.       break;
  58.     }
  59.     default: {
  60.       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
  61.     }
  62.   }
  63.   lua_rawseti(L, 1, pos);  /* t[pos] = v */
  64.   return 0;
  65. }
  66.  
  67.  
  68. static int tremove (lua_State *L) {
  69.   int e = aux_getn(L, 1);
  70.   int pos = luaL_optint(L, 2, e);
  71.   if (!(1 <= pos && pos <= e))  /* position is outside bounds? */
  72.     return 0;  /* nothing to remove */
  73.   lua_rawgeti(L, 1, pos);  /* result = t[pos] */
  74.   for ( ;pos<e; pos++) {
  75.     lua_rawgeti(L, 1, pos+1);
  76.     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
  77.   }
  78.   lua_pushnil(L);
  79.   lua_rawseti(L, 1, e);  /* t[e] = nil */
  80.   return 1;
  81. }
  82.  
  83.  
  84. static void addfield (lua_State *L, luaL_Buffer *b, int i) {
  85.   lua_rawgeti(L, 1, i);
  86.   if (!lua_isstring(L, -1))
  87.     luaL_error(L, "invalid value (%s) at index %d in table for "
  88.                   LUA_QL("concat"), luaL_typename(L, -1), i);
  89.   luaL_addvalue(b);
  90. }
  91.  
  92.  
  93. static int tconcat (lua_State *L) {
  94.   luaL_Buffer b;
  95.   size_t lsep;
  96.   int i, last;
  97.   const char *sep = luaL_optlstring(L, 2, "", &lsep);
  98.   luaL_checktype(L, 1, LUA_TTABLE);
  99.   i = luaL_optint(L, 3, 1);
  100.   last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1));
  101.   luaL_buffinit(L, &b);
  102.   for (; i < last; i++) {
  103.     addfield(L, &b, i);
  104.     luaL_addlstring(&b, sep, lsep);
  105.   }
  106.   if (i == last)  /* add last value (if interval was not empty) */
  107.     addfield(L, &b, i);
  108.   luaL_pushresult(&b);
  109.   return 1;
  110. }
  111.  
  112.  
  113. /*
  114. ** {======================================================
  115. ** Pack/unpack
  116. ** =======================================================
  117. */
  118.  
  119. static int pack (lua_State *L) {
  120.   int n = lua_gettop(L);  /* number of elements to pack */
  121.   lua_createtable(L, n, 1);  /* create result table */
  122.   lua_pushinteger(L, n);
  123.   lua_setfield(L, -2, "n");  /* t.n = number of elements */
  124.   if (n > 0) {  /* at least one element? */
  125.     int i;
  126.     lua_pushvalue(L, 1);
  127.     lua_rawseti(L, -2, 1);  /* insert first element */
  128.     lua_replace(L, 1);  /* move table into index 1 */
  129.     for (i = n; i >= 2; i--)  /* assign other elements */
  130.       lua_rawseti(L, 1, i);
  131.   }
  132.   return 1;  /* return table */
  133. }
  134.  
  135.  
  136. static int unpack (lua_State *L) {
  137.   int i, e, n;
  138.   luaL_checktype(L, 1, LUA_TTABLE);
  139.   i = luaL_optint(L, 2, 1);
  140.   e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
  141.   if (i > e) return 0;  /* empty range */
  142.   n = e - i + 1;  /* number of elements */
  143.   if (n <= 0 || !lua_checkstack(L, n))  /* n <= 0 means arith. overflow */
  144.     return luaL_error(L, "too many results to unpack");
  145.   lua_rawgeti(L, 1, i);  /* push arg[i] (avoiding overflow problems) */
  146.   while (i++ < e)  /* push arg[i + 1...e] */
  147.     lua_rawgeti(L, 1, i);
  148.   return n;
  149. }
  150.  
  151. /* }====================================================== */
  152.  
  153.  
  154.  
  155. /*
  156. ** {======================================================
  157. ** Quicksort
  158. ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
  159. **  Addison-Wesley, 1993.)
  160. ** =======================================================
  161. */
  162.  
  163.  
  164. static void set2 (lua_State *L, int i, int j) {
  165.   lua_rawseti(L, 1, i);
  166.   lua_rawseti(L, 1, j);
  167. }
  168.  
  169. static int sort_comp (lua_State *L, int a, int b) {
  170.   if (!lua_isnil(L, 2)) {  /* function? */
  171.     int res;
  172.     lua_pushvalue(L, 2);
  173.     lua_pushvalue(L, a-1);  /* -1 to compensate function */
  174.     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
  175.     lua_call(L, 2, 1);
  176.     res = lua_toboolean(L, -1);
  177.     lua_pop(L, 1);
  178.     return res;
  179.   }
  180.   else  /* a < b? */
  181.     return lua_compare(L, a, b, LUA_OPLT);
  182. }
  183.  
  184. static void auxsort (lua_State *L, int l, int u) {
  185.   while (l < u) {  /* for tail recursion */
  186.     int i, j;
  187.     /* sort elements a[l], a[(l+u)/2] and a[u] */
  188.     lua_rawgeti(L, 1, l);
  189.     lua_rawgeti(L, 1, u);
  190.     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
  191.       set2(L, l, u);  /* swap a[l] - a[u] */
  192.     else
  193.       lua_pop(L, 2);
  194.     if (u-l == 1) break;  /* only 2 elements */
  195.     i = (l+u)/2;
  196.     lua_rawgeti(L, 1, i);
  197.     lua_rawgeti(L, 1, l);
  198.     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
  199.       set2(L, i, l);
  200.     else {
  201.       lua_pop(L, 1);  /* remove a[l] */
  202.       lua_rawgeti(L, 1, u);
  203.       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
  204.         set2(L, i, u);
  205.       else
  206.         lua_pop(L, 2);
  207.     }
  208.     if (u-l == 2) break;  /* only 3 elements */
  209.     lua_rawgeti(L, 1, i);  /* Pivot */
  210.     lua_pushvalue(L, -1);
  211.     lua_rawgeti(L, 1, u-1);
  212.     set2(L, i, u-1);
  213.     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
  214.     i = l; j = u-1;
  215.     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
  216.       /* repeat ++i until a[i] >= P */
  217.       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
  218.         if (i>=u) luaL_error(L, "invalid order function for sorting");
  219.         lua_pop(L, 1);  /* remove a[i] */
  220.       }
  221.       /* repeat --j until a[j] <= P */
  222.       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
  223.         if (j<=l) luaL_error(L, "invalid order function for sorting");
  224.         lua_pop(L, 1);  /* remove a[j] */
  225.       }
  226.       if (j<i) {
  227.         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
  228.         break;
  229.       }
  230.       set2(L, i, j);
  231.     }
  232.     lua_rawgeti(L, 1, u-1);
  233.     lua_rawgeti(L, 1, i);
  234.     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
  235.     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
  236.     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
  237.     if (i-l < u-i) {
  238.       j=l; i=i-1; l=i+2;
  239.     }
  240.     else {
  241.       j=i+1; i=u; u=j-2;
  242.     }
  243.     auxsort(L, j, i);  /* call recursively the smaller one */
  244.   }  /* repeat the routine for the larger one */
  245. }
  246.  
  247. static int sort (lua_State *L) {
  248.   int n = aux_getn(L, 1);
  249.   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
  250.   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
  251.     luaL_checktype(L, 2, LUA_TFUNCTION);
  252.   lua_settop(L, 2);  /* make sure there is two arguments */
  253.   auxsort(L, 1, n);
  254.   return 0;
  255. }
  256.  
  257. /* }====================================================== */
  258.  
  259.  
  260. static const luaL_Reg tab_funcs[] = {
  261.   {"concat", tconcat},
  262. #if defined(LUA_COMPAT_MAXN)
  263.   {"maxn", maxn},
  264. #endif
  265.   {"insert", tinsert},
  266.   {"pack", pack},
  267.   {"unpack", unpack},
  268.   {"remove", tremove},
  269.   {"sort", sort},
  270.   {NULL, NULL}
  271. };
  272.  
  273.  
  274. LUAMOD_API int luaopen_table (lua_State *L) {
  275.   luaL_newlib(L, tab_funcs);
  276. #if defined(LUA_COMPAT_UNPACK)
  277.   /* _G.unpack = table.unpack */
  278.   lua_getfield(L, -1, "unpack");
  279.   lua_setglobal(L, "unpack");
  280. #endif
  281.   return 1;
  282. }
  283.  
  284.