FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/lua/ltablib.c

     /*
     ** $Id: ltablib.c,v 1.65.1.2 2014/05/07 16:32:55 roberto Exp $
     ** Library for Table Manipulation
     ** See Copyright Notice in lua.h
     */
     
     
     #define ltablib_c
     #define LUA_LIB
    
    #include <sys/lua/lua.h>
    
    #include <sys/lua/lauxlib.h>
    #include <sys/lua/lualib.h>
    
    
    #define aux_getn(L,n)   (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n))
    
    
    
    #if defined(LUA_COMPAT_MAXN)
    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;
    }
    #endif
    
    
    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 */
          luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds");
          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"));
        }
      }
      lua_rawseti(L, 1, pos);  /* t[pos] = v */
      return 0;
    }
    
    
    static int tremove (lua_State *L) {
      int size = aux_getn(L, 1);
      int pos = luaL_optint(L, 2, size);
      if (pos != size)  /* validate 'pos' if given */
        luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");
      lua_rawgeti(L, 1, pos);  /* result = t[pos] */
      for ( ; pos < size; pos++) {
        lua_rawgeti(L, 1, pos+1);
        lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
      }
      lua_pushnil(L);
      lua_rawseti(L, 1, pos);  /* t[pos] = 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_len(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;
   }
   
   
   /*
   ** {======================================================
   ** Pack/unpack
   ** =======================================================
   */
   
   static int pack (lua_State *L) {
     int n = lua_gettop(L);  /* number of elements to pack */
     lua_createtable(L, n, 1);  /* create result table */
     lua_pushinteger(L, n);
     lua_setfield(L, -2, "n");  /* t.n = number of elements */
     if (n > 0) {  /* at least one element? */
       int i;
       lua_pushvalue(L, 1);
       lua_rawseti(L, -2, 1);  /* insert first element */
       lua_replace(L, 1);  /* move table into index 1 */
       for (i = n; i >= 2; i--)  /* assign other elements */
         lua_rawseti(L, 1, i);
     }
     return 1;  /* return table */
   }
   
   
   static int unpack (lua_State *L) {
     int i, e;
     unsigned int n;
     luaL_checktype(L, 1, LUA_TTABLE);
     i = luaL_optint(L, 2, 1);
     e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
     if (i > e) return 0;  /* empty range */
     n = (unsigned int)e - (unsigned int)i;  /* number of elements minus 1 */
     if (n > (INT_MAX - 10) || !lua_checkstack(L, ++n))
       return luaL_error(L, "too many results to unpack");
     lua_rawgeti(L, 1, i);  /* push arg[i] (avoiding overflow problems) */
     while (i++ < e)  /* push arg[i + 1...e] */
       lua_rawgeti(L, 1, i);
     return n;
   }
   
   /* }====================================================== */
   
   
   
   /*
   ** {======================================================
   ** 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_compare(L, a, b, LUA_OPLT);
   }
   
   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 tsort (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},
   #if defined(LUA_COMPAT_MAXN)
     {"maxn", maxn},
   #endif
     {"insert", tinsert},
     {"pack", pack},
     {"unpack", unpack},
     {"remove", tremove},
     {"sort", tsort},
     {NULL, NULL}
   };
   
   
   LUAMOD_API int luaopen_table (lua_State *L) {
     luaL_newlib(L, tab_funcs);
   #if defined(LUA_COMPAT_UNPACK)
     /* _G.unpack = table.unpack */
     lua_getfield(L, -1, "unpack");
     lua_setglobal(L, "unpack");
   #endif
     return 1;
   }
   
   #if defined(_KERNEL)
   
   EXPORT_SYMBOL(luaopen_table);
   
   #endif

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