aboutsummaryrefslogtreecommitdiff
path: root/src/ltablib.js
blob: 05c9c095fe41530a42c35d28742f20a3cebcfd92 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
"use strict";

const assert  = require('assert');

const lua     = require('./lua.js');
const lauxlib = require('./lauxlib.js');
const luaconf = require('./luaconf.js');


/*
** Operations that an object must define to mimic a table
** (some functions only need some of them)
*/
const TAB_R  = 1;               /* read */
const TAB_W  = 2;               /* write */
const TAB_L  = 4;               /* length */
const TAB_RW = (TAB_R | TAB_W); /* read/write */

const checkfield = function(L, key, n) {
    lua.lua_pushstring(L, key);
    return lua.lua_rawget(L, -n) !== lua.LUA_TNIL;
};

/*
** Check that 'arg' either is a table or can behave like one (that is,
** has a metatable with the required metamethods)
*/
const checktab = function(L, arg, what) {
    if (lua.lua_type(L, arg) !== lua.LUA_TTABLE) {  /* is it not a table? */
        let n = 1;
        if (lua.lua_getmetatable(L, arg) &&  /* must have metatable */
            (!(what & TAB_R) || checkfield(L, lua.to_luastring("__index", true), ++n)) &&
            (!(what & TAB_W) || checkfield(L, lua.to_luastring("__newindex", true), ++n)) &&
            (!(what & TAB_L) || checkfield(L, lua.to_luastring("__len", true), ++n))) {
            lua.lua_pop(L, n);  /* pop metatable and tested metamethods */
        }
        else
            lauxlib.luaL_checktype(L, arg, lua.LUA_TTABLE);  /* force an error */
    }
};

const aux_getn = function(L, n, w) {
    checktab(L, n, w | TAB_L);
    return lauxlib.luaL_len(L, n);
};

const addfield = function(L, b, i) {
    lua.lua_geti(L, 1, i);
    if (!lua.lua_isstring(L, -1))
        lauxlib.luaL_error(L, lua.to_luastring("invalid value (%s) at index %d in table for 'concat'"),
            lauxlib.luaL_typename(L, -1), i);

    lauxlib.luaL_addvalue(b);
};

const tinsert = function(L) {
    let e = aux_getn(L, 1, TAB_RW) + 1;  /* first empty element */
    let pos;
    switch (lua.lua_gettop(L)) {
        case 2:
            pos = e;
            break;
        case 3: {
            pos = lauxlib.luaL_checkinteger(L, 2);  /* 2nd argument is the position */
            lauxlib.luaL_argcheck(L, 1 <= pos && pos <= e, 2, lua.to_luastring("position out of bounds", true));
            for (let i = e; i > pos; i--) {  /* move up elements */
                lua.lua_geti(L, 1, i - 1);
                lua.lua_seti(L, 1, i);  /* t[i] = t[i - 1] */
            }
            break;
        }
        default: {
            return lauxlib.luaL_error(L, lua.to_luastring("wrong number of arguments to 'insert'", true));
        }
    }

    lua.lua_seti(L, 1, pos);  /* t[pos] = v */
    return 0;
};

const tremove = function(L) {
    let size = aux_getn(L, 1, TAB_RW);
    let pos = lauxlib.luaL_optinteger(L, 2, size);
    if (pos !== size)  /* validate 'pos' if given */
        lauxlib.luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, lua.to_luastring("position out of bounds", true));
    lua.lua_geti(L, 1, pos);  /* result = t[pos] */
    for (; pos < size; pos++) {
        lua.lua_geti(L, 1, pos + 1);
        lua.lua_seti(L, 1, pos);  /* t[pos] = t[pos + 1] */
    }
    lua.lua_pushnil(L);
    lua.lua_seti(L, 1, pos);  /* t[pos] = nil */
    return 1;
};

/*
** 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.
*/
const tmove = function(L) {
    let f = lauxlib.luaL_checkinteger(L, 2);
    let e = lauxlib.luaL_checkinteger(L, 3);
    let t = lauxlib.luaL_checkinteger(L, 4);
    let tt = !lua.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 */
        lauxlib.luaL_argcheck(L, f > 0 || e < luaconf.LUA_MAXINTEGER + f, 3, lua.to_luastring("too many elements to move", true));
        let n = e - f + 1;  /* number of elements to move */
        lauxlib.luaL_argcheck(L, t <= luaconf.LUA_MAXINTEGER - n + 1, 4, lua.to_luastring("destination wrap around", true));

        if (t > e || t <= f || (tt !== 1 && lua.lua_compare(L, 1, tt, lua.LUA_OPEQ) !== 1)) {
            for (let i = 0; i < n; i++) {
                lua.lua_geti(L, 1, f + i);
                lua.lua_seti(L, tt, t + i);
            }
        } else {
            for (let i = n - 1; i >= 0; i--) {
                lua.lua_geti(L, 1, f + i);
                lua.lua_seti(L, tt, t + i);
            }
        }
    }

    lua.lua_pushvalue(L, tt);  /* return destination table */
    return 1;
};

const tconcat = function(L) {
    let last = aux_getn(L, 1, TAB_R);
    let sep = lauxlib.luaL_optlstring(L, 2, []);
    let i = lauxlib.luaL_optinteger(L, 3, 1);
    last = lauxlib.luaL_optinteger(L, 4, last);

    let b = new lauxlib.luaL_Buffer();
    lauxlib.luaL_buffinit(L, b);

    for (; i < last; i++) {
        addfield(L, b, i);
        lauxlib.luaL_addlstring(b, sep);
    }

    if (i === last)
        addfield(L, b, i);

    lauxlib.luaL_pushresult(b);

    return 1;
};

const pack = function(L) {
    let n = lua.lua_gettop(L);  /* number of elements to pack */
    lua.lua_createtable(L, n, 1);  /* create result table */
    lua.lua_insert(L, 1);  /* put it at index 1 */
    for (let i = n; i >= 1; i--)  /* assign elements */
        lua.lua_seti(L, 1, i);
    lua.lua_pushinteger(L, n);
    lua.lua_setfield(L, 1, ["n".charCodeAt(0)]);  /* t.n = number of elements */
    return 1;  /* return table */
};

const unpack = function(L) {
    let i = lauxlib.luaL_optinteger(L, 2, 1);
    let e = lauxlib.luaL_opt(L, lauxlib.luaL_checkinteger, 3, lauxlib.luaL_len(L, 1));
    if (i > e) return 0;  /* empty range */
    let n = e - i;  /* number of elements minus 1 (avoid overflows) */
    if (n >= Number.MAX_SAFE_INTEGER || !lua.lua_checkstack(L, ++n))
        return lauxlib.luaL_error(L, lua.to_luastring("too many results to unpack", true));
    for (; i < e; i++)  /* push arg[i..e - 1] (to avoid overflows) */
        lua.lua_geti(L, 1, i);
    lua.lua_geti(L, 1, e);  /* push last element */
    return n;
};

const l_randomizePivot = function() {
    return Math.floor(Math.random()*1<<32);
};

const RANLIMIT = 100;

const set2 = function(L, i, j) {
    lua.lua_seti(L, 1, i);
    lua.lua_seti(L, 1, j);
};

const sort_comp = function(L, a, b) {
    if (lua.lua_isnil(L, 2))  /* no function? */
        return lua.lua_compare(L, a, b, lua.LUA_OPLT);  /* a < b */
    else {  /* function */
        lua.lua_pushvalue(L, 2);    /* push function */
        lua.lua_pushvalue(L, a-1);  /* -1 to compensate function */
        lua.lua_pushvalue(L, b-2);  /* -2 to compensate function and 'a' */
        lua.lua_call(L, 2, 1);      /* call function */
        let res = lua.lua_toboolean(L, -1);  /* get result */
        lua.lua_pop(L, 1);          /* pop result */
        return res;
    }
};

const partition = function(L, lo, up) {
    let i = lo;  /* will be incremented before first use */
    let 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.lua_geti(L, 1, ++i), sort_comp(L, -1, -2)) {
            if (i == up - 1)  /* a[i] < P  but a[up - 1] == P  ?? */
                lauxlib.luaL_error(L, lua.to_luastring("invalid order function for sorting"));
            lua.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.lua_geti(L, 1, --j), sort_comp(L, -3, -1)) {
            if (j < i)  /* j < i  but  a[j] > P ?? */
                lauxlib.luaL_error(L, lua.to_luastring("invalid order function for sorting"));
            lua.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.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);
    }
};

const choosePivot = function(lo, up, rnd) {
    let r4 = Math.floor((up - lo) / 4);  /* range/4 */
    let p = rnd % (r4 * 2) + (lo + r4);
    assert(lo + r4 <= p && p <= up - r4);
    return p;
};

const auxsort = function(L, lo, up, rnd) {
    while (lo < up) {  /* loop for tail recursion */
        /* sort elements 'lo', 'p', and 'up' */
        lua.lua_geti(L, 1, lo);
        lua.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.lua_pop(L, 2);  /* remove both values */
        if (up - lo == 1)  /* only 2 elements? */
            return;  /* already sorted */
        let p;  /* Pivot index */
        if (up - lo < RANLIMIT || rnd === 0)  /* small interval or no randomize? */
            p = Math.floor((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.lua_geti(L, 1, p);
        lua.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.lua_pop(L, 1);  /* remove a[lo] */
            lua.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.lua_pop(L, 2);
        }
        if (up - lo == 2)  /* only 3 elements? */
            return;  /* already sorted */
        lua.lua_geti(L, 1, p);  /* get middle element (Pivot) */
        lua.lua_pushvalue(L, -1);  /* push Pivot */
        lua.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);
        let n;
        /* 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 {
            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) */
        }
        if ((up - lo) / 128 > n) /* partition too imbalanced? */
            rnd = l_randomizePivot();  /* try a new randomization */
    }  /* tail call auxsort(L, lo, up, rnd) */
};

const sort = function(L) {
    let n = aux_getn(L, 1, TAB_RW);
    if (n > 1) {  /* non-trivial interval? */
        lauxlib.luaL_argcheck(L, n < luaconf.LUA_MAXINTEGER, 1, lua.to_luastring("array too big", true));
        if (!lua.lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
            lauxlib.luaL_checktype(L, 2, lua.LUA_TFUNCTION);  /* must be a function */
        lua.lua_settop(L, 2);  /* make sure there are two arguments */
        auxsort(L, 1, n, 0);
    }
    return 0;
};

const tab_funcs = {
    "concat": tconcat,
    "insert": tinsert,
    "move":   tmove,
    "pack":   pack,
    "remove": tremove,
    "sort":   sort,
    "unpack": unpack
};

const luaopen_table = function(L) {
    lauxlib.luaL_newlib(L, tab_funcs);
    return 1;
};

module.exports.luaopen_table = luaopen_table;