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-rw-r--r--lua/ltablib.c400
1 files changed, 283 insertions, 117 deletions
diff --git a/lua/ltablib.c b/lua/ltablib.c
index 6001224..b3c9a7c 100644
--- a/lua/ltablib.c
+++ b/lua/ltablib.c
@@ -1,23 +1,61 @@
/*
-** $Id: ltablib.c,v 1.65.1.1 2013/04/12 18:48:47 roberto Exp $
+** $Id: ltablib.c,v 1.90 2015/11/25 12:48:57 roberto Exp $
** Library for Table Manipulation
** See Copyright Notice in lua.h
*/
-
-#include <stddef.h>
-
#define ltablib_c
#define LUA_LIB
+#include "lprefix.h"
+
+
+#include <limits.h>
+#include <stddef.h>
+#include <string.h>
+
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
-#define aux_getn(L,n) (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n))
+/*
+** Operations that an object must define to mimic a table
+** (some functions only need some of them)
+*/
+#define TAB_R 1 /* read */
+#define TAB_W 2 /* write */
+#define TAB_L 4 /* length */
+#define TAB_RW (TAB_R | TAB_W) /* read/write */
+
+#define aux_getn(L,n,w) (checktab(L, n, (w) | TAB_L), luaL_len(L, n))
+
+
+static int checkfield (lua_State *L, const char *key, int n) {
+ lua_pushstring(L, key);
+ return (lua_rawget(L, -n) != LUA_TNIL);
+}
+
+
+/*
+** Check that 'arg' either is a table or can behave like one (that is,
+** has a metatable with the required metamethods)
+*/
+static void checktab (lua_State *L, int arg, int what) {
+ if (lua_type(L, arg) != LUA_TTABLE) { /* is it not a table? */
+ int n = 1; /* number of elements to pop */
+ if (lua_getmetatable(L, arg) && /* must have metatable */
+ (!(what & TAB_R) || checkfield(L, "__index", ++n)) &&
+ (!(what & TAB_W) || checkfield(L, "__newindex", ++n)) &&
+ (!(what & TAB_L) || checkfield(L, "__len", ++n))) {
+ lua_pop(L, n); /* pop metatable and tested metamethods */
+ }
+ else
+ luaL_argerror(L, arg, "table expected"); /* force an error */
+ }
+}
#if defined(LUA_COMPAT_MAXN)
@@ -39,65 +77,102 @@ static int maxn (lua_State *L) {
static int tinsert (lua_State *L) {
- int e = aux_getn(L, 1) + 1; /* first empty element */
- int pos; /* where to insert new element */
+ lua_Integer e = aux_getn(L, 1, TAB_RW) + 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: {
- int i;
- pos = luaL_checkint(L, 2); /* 2nd argument is the position */
+ 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 */
- lua_rawgeti(L, 1, i-1);
- lua_rawseti(L, 1, i); /* t[i] = t[i-1] */
+ lua_geti(L, 1, i - 1);
+ lua_seti(L, 1, i); /* t[i] = t[i - 1] */
}
break;
}
default: {
- return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
+ return luaL_error(L, "wrong number of arguments to 'insert'");
}
}
- lua_rawseti(L, 1, pos); /* t[pos] = v */
+ lua_seti(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);
+ lua_Integer size = aux_getn(L, 1, TAB_RW);
+ 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");
- lua_rawgeti(L, 1, pos); /* result = t[pos] */
+ lua_geti(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_geti(L, 1, pos + 1);
+ lua_seti(L, 1, pos); /* t[pos] = t[pos + 1] */
}
lua_pushnil(L);
- lua_rawseti(L, 1, pos); /* t[pos] = nil */
+ lua_seti(L, 1, pos); /* t[pos] = nil */
return 1;
}
-static void addfield (lua_State *L, luaL_Buffer *b, int i) {
- lua_rawgeti(L, 1, i);
+/*
+** Copy elements (1[f], ..., 1[e]) into (tt[t], tt[t+1], ...). Whenever
+** possible, copy in increasing order, which is better for rehashing.
+** "possible" means destination after original range, or smaller
+** than origin, or copying to another table.
+*/
+static int tmove (lua_State *L) {
+ 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 */
+ checktab(L, 1, TAB_R);
+ checktab(L, tt, TAB_W);
+ if (e >= f) { /* otherwise, nothing to move */
+ lua_Integer n, i;
+ luaL_argcheck(L, f > 0 || e < LUA_MAXINTEGER + f, 3,
+ "too many elements to move");
+ n = e - f + 1; /* number of elements to move */
+ luaL_argcheck(L, t <= LUA_MAXINTEGER - n + 1, 4,
+ "destination wrap around");
+ if (t > e || t <= f || tt != 1) {
+ for (i = 0; i < n; i++) {
+ lua_geti(L, 1, f + i);
+ lua_seti(L, tt, t + i);
+ }
+ }
+ else {
+ for (i = n - 1; i >= 0; i--) {
+ lua_geti(L, 1, f + i);
+ lua_seti(L, tt, t + i);
+ }
+ }
+ }
+ lua_pushvalue(L, tt); /* return "to table" */
+ return 1;
+}
+
+
+static void addfield (lua_State *L, luaL_Buffer *b, lua_Integer i) {
+ lua_geti(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_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) {
luaL_Buffer b;
+ lua_Integer last = aux_getn(L, 1, TAB_R);
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));
+ lua_Integer i = luaL_optinteger(L, 3, 1);
+ last = luaL_opt(L, luaL_checkinteger, 4, last);
luaL_buffinit(L, &b);
for (; i < last; i++) {
addfield(L, &b, i);
@@ -117,35 +192,31 @@ static int tconcat (lua_State *L) {
*/
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_seti(L, 1, i);
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);
- }
+ lua_setfield(L, 1, "n"); /* t.n = number of elements */
return 1; /* return table */
}
static int unpack (lua_State *L) {
- int i, e, n;
- luaL_checktype(L, 1, LUA_TTABLE);
- i = luaL_optint(L, 2, 1);
- e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
+ lua_Unsigned n;
+ lua_Integer i = luaL_optinteger(L, 2, 1);
+ lua_Integer e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1));
if (i > e) return 0; /* empty range */
- n = e - i + 1; /* number of elements */
- if (n <= 0 || !lua_checkstack(L, n)) /* n <= 0 means arith. overflow */
+ 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");
- 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;
+ for (; i < e; i++) { /* push arg[i..e - 1] (to avoid overflows) */
+ lua_geti(L, 1, i);
+ }
+ lua_geti(L, 1, e); /* push last element */
+ return (int)n;
}
/* }====================================================== */
@@ -155,102 +226,196 @@ static int unpack (lua_State *L) {
/*
** {======================================================
** Quicksort
-** (based on `Algorithms in MODULA-3', Robert Sedgewick;
+** (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);
+/*
+** Produce a "random" 'unsigned int' to randomize pivot choice. This
+** macro is used only when 'sort' detects a big imbalance in the result
+** of a partition. (If you don't want/need this "randomness", ~0 is a
+** good choice.)
+*/
+#if !defined(l_randomizePivot) /* { */
+
+#include <time.h>
+
+/* size of 'e' measured in number of 'unsigned int's */
+#define sof(e) (sizeof(e) / sizeof(unsigned int))
+
+/*
+** Use 'time' and 'clock' as sources of "randomness". Because we don't
+** know the types 'clock_t' and 'time_t', we cannot cast them to
+** anything without risking overflows. A safe way to use their values
+** is to copy them to an array of a known type and use the array values.
+*/
+static unsigned int l_randomizePivot (void) {
+ clock_t c = clock();
+ time_t t = time(NULL);
+ unsigned int buff[sof(c) + sof(t)];
+ unsigned int i, rnd = 0;
+ memcpy(buff, &c, sof(c) * sizeof(unsigned int));
+ memcpy(buff + sof(c), &t, sof(t) * sizeof(unsigned int));
+ for (i = 0; i < sof(buff); i++)
+ rnd += buff[i];
+ return rnd;
}
+#endif /* } */
+
+
+/* arrays larger than 'RANLIMIT' may use randomized pivots */
+#define RANLIMIT 100u
+
+
+static void set2 (lua_State *L, unsigned int i, unsigned int j) {
+ lua_seti(L, 1, i);
+ lua_seti(L, 1, j);
+}
+
+
+/*
+** Return true iff value at stack index 'a' is less than the value at
+** index 'b' (according to the order of the sort).
+*/
static int sort_comp (lua_State *L, int a, int b) {
- if (!lua_isnil(L, 2)) { /* function? */
+ if (lua_isnil(L, 2)) /* no function? */
+ return lua_compare(L, a, b, LUA_OPLT); /* a < b */
+ else { /* function */
int res;
- lua_pushvalue(L, 2);
+ lua_pushvalue(L, 2); /* push function */
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);
+ lua_pushvalue(L, b-2); /* -2 to compensate function and 'a' */
+ lua_call(L, 2, 1); /* call function */
+ res = lua_toboolean(L, -1); /* get result */
+ lua_pop(L, 1); /* pop result */
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] */
+
+/*
+** Does the partition: Pivot P is at the top of the stack.
+** precondition: a[lo] <= P == a[up-1] <= a[up],
+** so it only needs to do the partition from lo + 1 to up - 2.
+** Pos-condition: a[lo .. i - 1] <= a[i] == P <= a[i + 1 .. up]
+** returns 'i'.
+*/
+static unsigned int partition (lua_State *L, unsigned int lo,
+ unsigned int up) {
+ unsigned int i = lo; /* will be incremented before first use */
+ unsigned int j = up - 1; /* will be decremented before first use */
+ /* loop invariant: a[lo .. i] <= P <= a[j .. up] */
+ for (;;) {
+ /* next loop: repeat ++i while a[i] < P */
+ while (lua_geti(L, 1, ++i), sort_comp(L, -1, -2)) {
+ if (i == up - 1) /* a[i] < P but a[up - 1] == P ?? */
+ luaL_error(L, "invalid order function for sorting");
+ lua_pop(L, 1); /* remove a[i] */
+ }
+ /* after the loop, a[i] >= P and a[lo .. i - 1] < P */
+ /* next loop: repeat --j while P < a[j] */
+ while (lua_geti(L, 1, --j), sort_comp(L, -3, -1)) {
+ if (j < i) /* j < i but a[j] > P ?? */
+ luaL_error(L, "invalid order function for sorting");
+ lua_pop(L, 1); /* remove a[j] */
+ }
+ /* after the loop, a[j] <= P and a[j + 1 .. up] >= P */
+ if (j < i) { /* no elements out of place? */
+ /* a[lo .. i - 1] <= P <= a[j + 1 .. i .. up] */
+ lua_pop(L, 1); /* pop a[j] */
+ /* swap pivot (a[up - 1]) with a[i] to satisfy pos-condition */
+ set2(L, up - 1, i);
+ return i;
+ }
+ /* otherwise, swap a[i] - a[j] to restore invariant and repeat */
+ set2(L, i, j);
+ }
+}
+
+
+/*
+** Choose an element in the middle (2nd-3th quarters) of [lo,up]
+** "randomized" by 'rnd'
+*/
+static unsigned int choosePivot (unsigned int lo, unsigned int up,
+ unsigned int rnd) {
+ unsigned int r4 = (unsigned int)(up - lo) / 4u; /* range/4 */
+ unsigned int p = rnd % (r4 * 2) + (lo + r4);
+ lua_assert(lo + r4 <= p && p <= up - r4);
+ return p;
+}
+
+
+/*
+** QuickSort algorithm (recursive function)
+*/
+static void auxsort (lua_State *L, unsigned int lo, unsigned int up,
+ unsigned int rnd) {
+ while (lo < up) { /* loop for tail recursion */
+ unsigned int p; /* Pivot index */
+ unsigned int n; /* to be used later */
+ /* sort elements 'lo', 'p', and 'up' */
+ lua_geti(L, 1, lo);
+ lua_geti(L, 1, up);
+ if (sort_comp(L, -1, -2)) /* a[up] < a[lo]? */
+ set2(L, lo, up); /* swap a[lo] - a[up] */
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);
+ lua_pop(L, 2); /* remove both values */
+ if (up - lo == 1) /* only 2 elements? */
+ return; /* already sorted */
+ if (up - lo < RANLIMIT || rnd == 0) /* small interval or no randomize? */
+ p = (lo + up)/2; /* middle element is a good pivot */
+ else /* for larger intervals, it is worth a random pivot */
+ p = choosePivot(lo, up, rnd);
+ lua_geti(L, 1, p);
+ lua_geti(L, 1, lo);
+ if (sort_comp(L, -2, -1)) /* a[p] < a[lo]? */
+ set2(L, p, lo); /* swap a[p] - a[lo] */
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);
+ lua_pop(L, 1); /* remove a[lo] */
+ lua_geti(L, 1, up);
+ if (sort_comp(L, -1, -2)) /* a[up] < a[p]? */
+ set2(L, p, up); /* swap a[up] - a[p] */
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;
+ if (up - lo == 2) /* only 3 elements? */
+ return; /* already sorted */
+ lua_geti(L, 1, p); /* get middle element (Pivot) */
+ lua_pushvalue(L, -1); /* push Pivot */
+ lua_geti(L, 1, up - 1); /* push a[up - 1] */
+ set2(L, p, up - 1); /* swap Pivot (a[p]) with a[up - 1] */
+ p = partition(L, lo, up);
+ /* a[lo .. p - 1] <= a[p] == P <= a[p + 1 .. up] */
+ if (p - lo < up - p) { /* lower interval is smaller? */
+ auxsort(L, lo, p - 1, rnd); /* call recursively for lower interval */
+ n = p - lo; /* size of smaller interval */
+ lo = p + 1; /* tail call for [p + 1 .. up] (upper interval) */
}
else {
- j=i+1; i=u; u=j-2;
+ auxsort(L, p + 1, up, rnd); /* call recursively for upper interval */
+ n = up - p; /* size of smaller interval */
+ up = p - 1; /* tail call for [lo .. p - 1] (lower interval) */
}
- auxsort(L, j, i); /* call recursively the smaller one */
- } /* repeat the routine for the larger one */
+ if ((up - lo) / 128u > n) /* partition too imbalanced? */
+ rnd = l_randomizePivot(); /* try a new randomization */
+ } /* tail call auxsort(L, lo, up, rnd) */
}
+
static int sort (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);
+ lua_Integer n = aux_getn(L, 1, TAB_RW);
+ if (n > 1) { /* non-trivial interval? */
+ luaL_argcheck(L, n < INT_MAX, 1, "array too big");
+ 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); /* must be a function */
+ lua_settop(L, 2); /* make sure there are two arguments */
+ auxsort(L, 1, (unsigned int)n, 0u);
+ }
return 0;
}
@@ -266,6 +431,7 @@ static const luaL_Reg tab_funcs[] = {
{"pack", pack},
{"unpack", unpack},
{"remove", tremove},
+ {"move", tmove},
{"sort", sort},
{NULL, NULL}
};
generated by cgit v1.2.1 (git 2.18.0) at 2024-05-05 03:19:37 +0000