library with table manipulation functions

ltablib.c

@@ -0,0 +1,308 @@
+/*
+** $Id: $
+** Library for Table Manipulation
+** See Copyright Notice in lua.h
+*/
+
+
+#include <stddef.h>
+
+#include "lua.h"
+
+#include "lauxlib.h"
+#include "luadebug.h"
+#include "lualib.h"
+
+
+
+
+static int luaB_foreachi (lua_State *L) {
+  int n, i;
+  luaL_check_type(L, 1, LUA_TTABLE);
+  luaL_check_type(L, 2, LUA_TFUNCTION);
+  n = lua_getn(L, 1);
+  for (i=1; i<=n; i++) {
+    lua_pushvalue(L, 2);  /* function */
+    lua_pushnumber(L, i);  /* 1st argument */
+    lua_rawgeti(L, 1, i);  /* 2nd argument */
+    lua_rawcall(L, 2, 1);
+    if (!lua_isnil(L, -1))
+      return 1;
+    lua_pop(L, 1);  /* remove nil result */
+  }
+  return 0;
+}
+
+
+static int luaB_foreach (lua_State *L) {
+  luaL_check_type(L, 1, LUA_TTABLE);
+  luaL_check_type(L, 2, LUA_TFUNCTION);
+  lua_pushnil(L);  /* first key */
+  for (;;) {
+    if (lua_next(L, 1) == 0)
+      return 0;
+    lua_pushvalue(L, 2);  /* function */
+    lua_pushvalue(L, -3);  /* key */
+    lua_pushvalue(L, -3);  /* value */
+    lua_rawcall(L, 2, 1);
+    if (!lua_isnil(L, -1))
+      return 1;
+    lua_pop(L, 2);  /* remove value and result */
+  }
+}
+
+
+static void aux_setn (lua_State *L, int t, int n) {
+  lua_pushliteral(L, "n");
+  lua_pushnumber(L, n);
+  lua_rawset(L, t);
+}
+
+
+static int luaB_getn (lua_State *L) {
+  luaL_check_type(L, 1, LUA_TTABLE);
+  lua_pushnumber(L, lua_getn(L, 1));
+  return 1;
+}
+
+
+static int luaB_tinsert (lua_State *L) {
+  int v = lua_gettop(L);  /* number of arguments */
+  int n, pos;
+  luaL_check_type(L, 1, LUA_TTABLE);
+  n = lua_getn(L, 1);
+  if (v == 2)  /* called with only 2 arguments */
+    pos = n+1;
+  else {
+    v = 3;  /* function may be called with more than 3 args */
+    pos = luaL_check_int(L, 2);  /* 2nd argument is the position */
+  }
+  if (pos > n+1) n = pos-1;
+  aux_setn(L, 1, n+1);  /* t.n = n+1 */
+  for (; n>=pos; n--) {
+    lua_rawgeti(L, 1, n);
+    lua_rawseti(L, 1, n+1);  /* t[n+1] = t[n] */
+  }
+  lua_pushvalue(L, v);
+  lua_rawseti(L, 1, pos);  /* t[pos] = v */
+  return 0;
+}
+
+
+static int luaB_tremove (lua_State *L) {
+  int pos, n;
+  luaL_check_type(L, 1, LUA_TTABLE);
+  n = lua_getn(L, 1);
+  pos = luaL_opt_int(L, 2, n);
+  if (n <= 0) return 0;  /* table is `empty' */
+  aux_setn(L, 1, n-1);  /* t.n = n-1 */
+  lua_rawgeti(L, 1, pos);  /* result = t[pos] */
+  for ( ;pos<n; pos++) {
+    lua_rawgeti(L, 1, pos+1);
+    lua_rawseti(L, 1, pos);  /* a[pos] = a[pos+1] */
+  }
+  lua_pushnil(L);
+  lua_rawseti(L, 1, n);  /* t[n] = nil */
+  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) {
+  /* WARNING: the caller (auxsort) must ensure stack space */
+  if (!lua_isnoneornil(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_rawcall(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) lua_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) lua_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 luaB_sort (lua_State *L) {
+  int n;
+  luaL_check_type(L, 1, LUA_TTABLE);
+  n = lua_getn(L, 1);
+  if (!lua_isnone(L, 2))  /* is there a 2nd argument? */
+    luaL_check_type(L, 2, LUA_TFUNCTION);
+  lua_settop(L, 2);  /* make sure there is two arguments */
+  auxsort(L, 1, n);
+  return 0;
+}
+
+/* }====================================================== */
+
+
+/*
+** {======================================================
+** Coroutine library
+** =======================================================
+*/
+
+
+static int luaB_resume (lua_State *L) {
+  lua_State *co = (lua_State *)lua_getfrombox(L, lua_upvalueindex(1));
+  lua_settop(L, 0);
+  if (lua_resume(L, co) != 0)
+    lua_error(L, "error running co-routine");
+  return lua_gettop(L);
+}
+
+
+
+static int gc_coroutine (lua_State *L) {
+  lua_State *co = (lua_State *)lua_getfrombox(L, 1);
+  lua_closethread(L, co);
+  return 0;
+}
+
+
+static int luaB_coroutine (lua_State *L) {
+  lua_State *NL;
+  int ref;
+  int i;
+  int n = lua_gettop(L);
+  luaL_arg_check(L, lua_isfunction(L, 1) && !lua_iscfunction(L, 1), 1,
+    "Lua function expected");
+  NL = lua_newthread(L);
+  if (NL == NULL) lua_error(L, "unable to create new thread");
+  /* move function and arguments from L to NL */
+  for (i=0; i<n; i++) {
+    ref = lua_ref(L, 1);
+    lua_getref(NL, ref);
+    lua_insert(NL, 1);
+    lua_unref(L, ref);
+  }
+  lua_cobegin(NL, n-1);
+  lua_newpointerbox(L, NL);
+  lua_pushliteral(L, "Coroutine");
+  lua_rawget(L, LUA_REGISTRYINDEX);
+  lua_setmetatable(L, -2);
+  lua_pushcclosure(L, luaB_resume, 1);
+  return 1;
+}
+
+
+static int luaB_yield (lua_State *L) {
+  return lua_yield(L, lua_gettop(L));
+}
+
+static const luaL_reg co_funcs[] = {
+  {"create", luaB_coroutine},
+  {"yield", luaB_yield},
+  {NULL, NULL}
+};
+
+
+static void co_open (lua_State *L) {
+  luaL_opennamedlib(L, "co", co_funcs, 0);
+  /* create metatable for coroutines */
+  lua_pushliteral(L, "Coroutine");
+  lua_newtable(L);
+  lua_pushliteral(L, "__gc");
+  lua_pushcfunction(L, gc_coroutine);
+  lua_rawset(L, -3);
+  lua_rawset(L, LUA_REGISTRYINDEX);
+}
+
+/* }====================================================== */
+
+
+static const luaL_reg tab_funcs[] = {
+  {"foreach", luaB_foreach},
+  {"foreachi", luaB_foreachi},
+  {"getn", luaB_getn},
+  {"sort", luaB_sort},
+  {"insert", luaB_tinsert},
+  {"remove", luaB_tremove},
+  {NULL, NULL}
+};
+
+
+LUALIB_API int lua_tablibopen (lua_State *L) {
+  luaL_opennamedlib(L, "tab", tab_funcs, 0);
+  co_open(L);
+  return 0;
+}
+