/*** $Id: ltablib.c,v 1.79 2014/11/02 19:19:04 roberto Exp $** Library for Table Manipulation** See Copyright Notice in lua.h*/ #define ltablib_c#define LUA_LIB #include "lprefix.h"  #include <limits.h>#include <stddef.h> #include "lua.h" #include "lauxlib.h"#include "lualib.h"   /*** Structure with table-access functions*/typedef struct {  int (*geti) (lua_State *L, int idx, lua_Integer n);  void (*seti) (lua_State *L, int idx, lua_Integer n);} TabA;  /*** Check that 'arg' has a table and set access functions in 'ta' to raw** or non-raw according to the presence of corresponding metamethods.*/static void checktab (lua_State *L, int arg, TabA *ta) {  ta->geti = NULL; ta->seti = NULL;  if (lua_getmetatable(L, arg)) {    lua_pushliteral(L, "__index");  /* 'index' metamethod */    if (lua_rawget(L, -2) != LUA_TNIL)      ta->geti = lua_geti;    lua_pushliteral(L, "__newindex");  /* 'newindex' metamethod */    if (lua_rawget(L, -3) != LUA_TNIL)      ta->seti = lua_seti;    lua_pop(L, 3);  /* pop metatable plus both metamethods */  }  if (ta->geti == NULL || ta->seti == NULL) {    luaL_checktype(L, arg, LUA_TTABLE);  /* must be table for raw methods */    if (ta->geti == NULL) ta->geti = lua_rawgeti;    if (ta->seti == NULL) ta->seti = lua_rawseti;  }}  #define aux_getn(L,n,ta)	(checktab(L, n, ta), 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) {  TabA ta;  lua_Integer e = aux_getn(L, 1, &ta) + 1;  /* first empty element */  lua_Integer 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: {      lua_Integer i;      pos = luaL_checkinteger(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 */        (*ta.geti)(L, 1, i - 1);        (*ta.seti)(L, 1, i);  /* t[i] = t[i - 1] */      }      break;    }    default: {      return luaL_error(L, "wrong number of arguments to 'insert'");    }  }  (*ta.seti)(L, 1, pos);  /* t[pos] = v */  return 0;}  static int tremove (lua_State *L) {  TabA ta;  lua_Integer size = aux_getn(L, 1, &ta);  lua_Integer pos = luaL_optinteger(L, 2, size);  if (pos != size)  /* validate 'pos' if given */    luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");  (*ta.geti)(L, 1, pos);  /* result = t[pos] */  for ( ; pos < size; pos++) {    (*ta.geti)(L, 1, pos + 1);    (*ta.seti)(L, 1, pos);  /* t[pos] = t[pos + 1] */  }  lua_pushnil(L);  (*ta.seti)(L, 1, pos);  /* t[pos] = nil */  return 1;}  static int tmove (lua_State *L) {  TabA ta;  lua_Integer f = luaL_checkinteger(L, 2);  lua_Integer e = luaL_checkinteger(L, 3);  lua_Integer t = luaL_checkinteger(L, 4);  int tt = !lua_isnoneornil(L, 5) ? 5 : 1;  /* destination table */  /* the following restriction avoids several problems with overflows */  luaL_argcheck(L, f > 0, 2, "initial position must be positive");  if (e >= f) {  /* otherwise, nothing to move */    lua_Integer n, i;    ta.geti = (luaL_getmetafield(L, 1, "__index") == LUA_TNIL)      ? (luaL_checktype(L, 1, LUA_TTABLE), lua_rawgeti)      : lua_geti;    ta.seti = (luaL_getmetafield(L, tt, "__newindex") == LUA_TNIL)      ? (luaL_checktype(L, tt, LUA_TTABLE), lua_rawseti)      : lua_seti;    n = e - f + 1;  /* number of elements to move */    if (t > f) {      for (i = n - 1; i >= 0; i--) {        (*ta.geti)(L, 1, f + i);        (*ta.seti)(L, tt, t + i);      }    }    else {      for (i = 0; i < n; i++) {        (*ta.geti)(L, 1, f + i);        (*ta.seti)(L, tt, t + i);      }    }  }  lua_pushvalue(L, tt);  /* return "to table" */  return 1;}  static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) {  (*ta->geti)(L, 1, i);  if (!lua_isstring(L, -1))    luaL_error(L, "invalid value (%s) at index %d in table for 'concat'",                  luaL_typename(L, -1), i);  luaL_addvalue(b);}  static int tconcat (lua_State *L) {  TabA ta;  luaL_Buffer b;  size_t lsep;  lua_Integer i, last;  const char *sep = luaL_optlstring(L, 2, "", &lsep);  checktab(L, 1, &ta);  i = luaL_optinteger(L, 3, 1);  last = luaL_opt(L, luaL_checkinteger, 4, luaL_len(L, 1));  luaL_buffinit(L, &b);  for (; i < last; i++) {    addfield(L, &b, &ta, i);    luaL_addlstring(&b, sep, lsep);  }  if (i == last)  /* add last value (if interval was not empty) */    addfield(L, &b, &ta, i);  luaL_pushresult(&b);  return 1;}  /*** {======================================================** Pack/unpack** =======================================================*/ static int pack (lua_State *L) {  int i;  int n = lua_gettop(L);  /* number of elements to pack */  lua_createtable(L, n, 1);  /* create result table */  lua_insert(L, 1);  /* put it at index 1 */  for (i = n; i >= 1; i--)  /* assign elements */    lua_rawseti(L, 1, i);  lua_pushinteger(L, n);  lua_setfield(L, 1, "n");  /* t.n = number of elements */  return 1;  /* return table */}  static int unpack (lua_State *L) {  TabA ta;  lua_Integer i, e;  lua_Unsigned n;  checktab(L, 1, &ta);  i = luaL_optinteger(L, 2, 1);  e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1));  if (i > e) return 0;  /* empty range */  n = (lua_Unsigned)e - i;  /* number of elements minus 1 (avoid overflows) */  if (n >= (unsigned int)INT_MAX  || !lua_checkstack(L, (int)(++n)))    return luaL_error(L, "too many results to unpack");  do {  /* must have at least one element */    (*ta.geti)(L, 1, i);  /* push arg[i..e] */  } while (i++ < e);    return (int)n;} /* }====================================================== */   /*** {======================================================** Quicksort** (based on 'Algorithms in MODULA-3', Robert Sedgewick;**  Addison-Wesley, 1993.)** =======================================================*/  static void set2 (lua_State *L, TabA *ta, int i, int j) {  (*ta->seti)(L, 1, i);  (*ta->seti)(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, TabA *ta, int l, int u) {  while (l < u) {  /* for tail recursion */    int i, j;    /* sort elements a[l], a[(l+u)/2] and a[u] */    (*ta->geti)(L, 1, l);    (*ta->geti)(L, 1, u);    if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */      set2(L, ta, l, u);  /* swap a[l] - a[u] */    else      lua_pop(L, 2);    if (u-l == 1) break;  /* only 2 elements */    i = (l+u)/2;    (*ta->geti)(L, 1, i);    (*ta->geti)(L, 1, l);    if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */      set2(L, ta, i, l);    else {      lua_pop(L, 1);  /* remove a[l] */      (*ta->geti)(L, 1, u);      if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */        set2(L, ta, i, u);      else        lua_pop(L, 2);    }    if (u-l == 2) break;  /* only 3 elements */    (*ta->geti)(L, 1, i);  /* Pivot */    lua_pushvalue(L, -1);    (*ta->geti)(L, 1, u-1);    set2(L, ta, 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 ((*ta->geti)(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 ((*ta->geti)(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, ta, i, j);    }    (*ta->geti)(L, 1, u-1);    (*ta->geti)(L, 1, i);    set2(L, ta, 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, ta, j, i);  /* call recursively the smaller one */  }  /* repeat the routine for the larger one */} static int sort (lua_State *L) {  TabA ta;  int n = (int)aux_getn(L, 1, &ta);  luaL_checkstack(L, 50, "");  /* assume array is smaller than 2^50 */  if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */    luaL_checktype(L, 2, LUA_TFUNCTION);  lua_settop(L, 2);  /* make sure there are two arguments */  auxsort(L, &ta, 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},  {"move", tmove},  {"sort", sort},  {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;}