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Root/lua/ltablib.cc

1/*
2** $Id: ltablib.c,v 1.38 2005/10/23 17:38:15 roberto Exp $
3** Library for Table Manipulation
4** See Copyright Notice in lua.h
5*/
6
7
8#include <stddef.h>
9
10#define ltablib_c
11#define LUA_LIB
12
13#include "lua.h"
14
15#include "lauxlib.h"
16#include "lualib.h"
17
18
19#define aux_getn(L,n)(luaL_checktype(L, n, LUA_TTABLE), luaL_getn(L, n))
20
21
22static int foreachi (lua_State *L) {
23 int i;
24 int n = aux_getn(L, 1);
25 luaL_checktype(L, 2, LUA_TFUNCTION);
26 for (i=1; i <= n; i++) {
27 lua_pushvalue(L, 2); /* function */
28 lua_pushinteger(L, i); /* 1st argument */
29 lua_rawgeti(L, 1, i); /* 2nd argument */
30 lua_call(L, 2, 1);
31 if (!lua_isnil(L, -1))
32 return 1;
33 lua_pop(L, 1); /* remove nil result */
34 }
35 return 0;
36}
37
38
39static int foreach (lua_State *L) {
40 luaL_checktype(L, 1, LUA_TTABLE);
41 luaL_checktype(L, 2, LUA_TFUNCTION);
42 lua_pushnil(L); /* first key */
43 while (lua_next(L, 1)) {
44 lua_pushvalue(L, 2); /* function */
45 lua_pushvalue(L, -3); /* key */
46 lua_pushvalue(L, -3); /* value */
47 lua_call(L, 2, 1);
48 if (!lua_isnil(L, -1))
49 return 1;
50 lua_pop(L, 2); /* remove value and result */
51 }
52 return 0;
53}
54
55
56static int maxn (lua_State *L) {
57 lua_Number max = 0;
58 luaL_checktype(L, 1, LUA_TTABLE);
59 lua_pushnil(L); /* first key */
60 while (lua_next(L, 1)) {
61 lua_pop(L, 1); /* remove value */
62 if (lua_type(L, -1) == LUA_TNUMBER) {
63 lua_Number v = lua_tonumber(L, -1);
64 if (v > max) max = v;
65 }
66 }
67 lua_pushnumber(L, max);
68 return 1;
69}
70
71
72static int getn (lua_State *L) {
73 lua_pushinteger(L, aux_getn(L, 1));
74 return 1;
75}
76
77
78static int setn (lua_State *L) {
79 luaL_checktype(L, 1, LUA_TTABLE);
80#ifndef luaL_setn
81 luaL_setn(L, 1, luaL_checkint(L, 2));
82#else
83 luaL_error(L, LUA_QL("setn") " is obsolete");
84#endif
85 lua_pushvalue(L, 1);
86 return 1;
87}
88
89
90static int tinsert (lua_State *L) {
91 int e = aux_getn(L, 1) + 1; /* first empty element */
92 int pos; /* where to insert new element */
93 switch (lua_gettop(L)) {
94 case 2: { /* called with only 2 arguments */
95 pos = e; /* insert new element at the end */
96 break;
97 }
98 case 3: {
99 int i;
100 pos = luaL_checkint(L, 2); /* 2nd argument is the position */
101 if (pos > e) e = pos; /* `grow' array if necessary */
102 for (i = e; i > pos; i--) { /* move up elements */
103 lua_rawgeti(L, 1, i-1);
104 lua_rawseti(L, 1, i); /* t[i] = t[i-1] */
105 }
106 break;
107 }
108 default: {
109 return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
110 }
111 }
112 luaL_setn(L, 1, e); /* new size */
113 lua_rawseti(L, 1, pos); /* t[pos] = v */
114 return 0;
115}
116
117
118static int tremove (lua_State *L) {
119 int e = aux_getn(L, 1);
120 int pos = luaL_optint(L, 2, e);
121 if (e == 0) return 0; /* table is `empty' */
122 luaL_setn(L, 1, e - 1); /* t.n = n-1 */
123 lua_rawgeti(L, 1, pos); /* result = t[pos] */
124 for ( ;pos<e; pos++) {
125 lua_rawgeti(L, 1, pos+1);
126 lua_rawseti(L, 1, pos); /* t[pos] = t[pos+1] */
127 }
128 lua_pushnil(L);
129 lua_rawseti(L, 1, e); /* t[e] = nil */
130 return 1;
131}
132
133
134static int tconcat (lua_State *L) {
135 luaL_Buffer b;
136 size_t lsep;
137 int i, last;
138 const char *sep = luaL_optlstring(L, 2, "", &lsep);
139 luaL_checktype(L, 1, LUA_TTABLE);
140 i = luaL_optint(L, 3, 1);
141 last = luaL_opt(L, luaL_checkint, 4, luaL_getn(L, 1));
142 luaL_buffinit(L, &b);
143 for (; i <= last; i++) {
144 lua_rawgeti(L, 1, i);
145 luaL_argcheck(L, lua_isstring(L, -1), 1, "table contains non-strings");
146 luaL_addvalue(&b);
147 if (i != last)
148 luaL_addlstring(&b, sep, lsep);
149 }
150 luaL_pushresult(&b);
151 return 1;
152}
153
154
155
156/*
157** {======================================================
158** Quicksort
159** (based on `Algorithms in MODULA-3', Robert Sedgewick;
160** Addison-Wesley, 1993.)
161*/
162
163
164static void set2 (lua_State *L, int i, int j) {
165 lua_rawseti(L, 1, i);
166 lua_rawseti(L, 1, j);
167}
168
169static int sort_comp (lua_State *L, int a, int b) {
170 if (!lua_isnil(L, 2)) { /* function? */
171 int res;
172 lua_pushvalue(L, 2);
173 lua_pushvalue(L, a-1); /* -1 to compensate function */
174 lua_pushvalue(L, b-2); /* -2 to compensate function and `a' */
175 lua_call(L, 2, 1);
176 res = lua_toboolean(L, -1);
177 lua_pop(L, 1);
178 return res;
179 }
180 else /* a < b? */
181 return lua_lessthan(L, a, b);
182}
183
184static void auxsort (lua_State *L, int l, int u) {
185 while (l < u) { /* for tail recursion */
186 int i, j;
187 /* sort elements a[l], a[(l+u)/2] and a[u] */
188 lua_rawgeti(L, 1, l);
189 lua_rawgeti(L, 1, u);
190 if (sort_comp(L, -1, -2)) /* a[u] < a[l]? */
191 set2(L, l, u); /* swap a[l] - a[u] */
192 else
193 lua_pop(L, 2);
194 if (u-l == 1) break; /* only 2 elements */
195 i = (l+u)/2;
196 lua_rawgeti(L, 1, i);
197 lua_rawgeti(L, 1, l);
198 if (sort_comp(L, -2, -1)) /* a[i]<a[l]? */
199 set2(L, i, l);
200 else {
201 lua_pop(L, 1); /* remove a[l] */
202 lua_rawgeti(L, 1, u);
203 if (sort_comp(L, -1, -2)) /* a[u]<a[i]? */
204 set2(L, i, u);
205 else
206 lua_pop(L, 2);
207 }
208 if (u-l == 2) break; /* only 3 elements */
209 lua_rawgeti(L, 1, i); /* Pivot */
210 lua_pushvalue(L, -1);
211 lua_rawgeti(L, 1, u-1);
212 set2(L, i, u-1);
213 /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
214 i = l; j = u-1;
215 for (;;) { /* invariant: a[l..i] <= P <= a[j..u] */
216 /* repeat ++i until a[i] >= P */
217 while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
218 if (i>u) luaL_error(L, "invalid order function for sorting");
219 lua_pop(L, 1); /* remove a[i] */
220 }
221 /* repeat --j until a[j] <= P */
222 while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
223 if (j<l) luaL_error(L, "invalid order function for sorting");
224 lua_pop(L, 1); /* remove a[j] */
225 }
226 if (j<i) {
227 lua_pop(L, 3); /* pop pivot, a[i], a[j] */
228 break;
229 }
230 set2(L, i, j);
231 }
232 lua_rawgeti(L, 1, u-1);
233 lua_rawgeti(L, 1, i);
234 set2(L, u-1, i); /* swap pivot (a[u-1]) with a[i] */
235 /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
236 /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
237 if (i-l < u-i) {
238 j=l; i=i-1; l=i+2;
239 }
240 else {
241 j=i+1; i=u; u=j-2;
242 }
243 auxsort(L, j, i); /* call recursively the smaller one */
244 } /* repeat the routine for the larger one */
245}
246
247static int sort (lua_State *L) {
248 int n = aux_getn(L, 1);
249 luaL_checkstack(L, 40, ""); /* assume array is smaller than 2^40 */
250 if (!lua_isnoneornil(L, 2)) /* is there a 2nd argument? */
251 luaL_checktype(L, 2, LUA_TFUNCTION);
252 lua_settop(L, 2); /* make sure there is two arguments */
253 auxsort(L, 1, n);
254 return 0;
255}
256
257/* }====================================================== */
258
259
260static const luaL_Reg tab_funcs[] = {
261 {"concat", tconcat},
262 {"foreach", foreach},
263 {"foreachi", foreachi},
264 {"getn", getn},
265 {"maxn", maxn},
266 {"insert", tinsert},
267 {"remove", tremove},
268 {"setn", setn},
269 {"sort", sort},
270 {NULL, NULL}
271};
272
273
274LUALIB_API int luaopen_table (lua_State *L) {
275 luaL_register(L, LUA_TABLIBNAME, tab_funcs);
276 return 1;
277}
278

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