ba8b5c17 |
1 | /* |
2 | ** $Id: ltablib.c,v 1.65 2013/03/07 18:17:24 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_len(L, n)) |
20 | |
21 | |
22 | |
23 | #if defined(LUA_COMPAT_MAXN) |
24 | static int maxn (lua_State *L) { |
25 | lua_Number max = 0; |
26 | luaL_checktype(L, 1, LUA_TTABLE); |
27 | lua_pushnil(L); /* first key */ |
28 | while (lua_next(L, 1)) { |
29 | lua_pop(L, 1); /* remove value */ |
30 | if (lua_type(L, -1) == LUA_TNUMBER) { |
31 | lua_Number v = lua_tonumber(L, -1); |
32 | if (v > max) max = v; |
33 | } |
34 | } |
35 | lua_pushnumber(L, max); |
36 | return 1; |
37 | } |
38 | #endif |
39 | |
40 | |
41 | static int tinsert (lua_State *L) { |
42 | int e = aux_getn(L, 1) + 1; /* first empty element */ |
43 | int pos; /* where to insert new element */ |
44 | switch (lua_gettop(L)) { |
45 | case 2: { /* called with only 2 arguments */ |
46 | pos = e; /* insert new element at the end */ |
47 | break; |
48 | } |
49 | case 3: { |
50 | int i; |
51 | pos = luaL_checkint(L, 2); /* 2nd argument is the position */ |
52 | luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds"); |
53 | for (i = e; i > pos; i--) { /* move up elements */ |
54 | lua_rawgeti(L, 1, i-1); |
55 | lua_rawseti(L, 1, i); /* t[i] = t[i-1] */ |
56 | } |
57 | break; |
58 | } |
59 | default: { |
60 | return luaL_error(L, "wrong number of arguments to " LUA_QL("insert")); |
61 | } |
62 | } |
63 | lua_rawseti(L, 1, pos); /* t[pos] = v */ |
64 | return 0; |
65 | } |
66 | |
67 | |
68 | static int tremove (lua_State *L) { |
69 | int size = aux_getn(L, 1); |
70 | int pos = luaL_optint(L, 2, size); |
71 | if (pos != size) /* validate 'pos' if given */ |
72 | luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds"); |
73 | lua_rawgeti(L, 1, pos); /* result = t[pos] */ |
74 | for ( ; pos < size; pos++) { |
75 | lua_rawgeti(L, 1, pos+1); |
76 | lua_rawseti(L, 1, pos); /* t[pos] = t[pos+1] */ |
77 | } |
78 | lua_pushnil(L); |
79 | lua_rawseti(L, 1, pos); /* t[pos] = nil */ |
80 | return 1; |
81 | } |
82 | |
83 | |
84 | static void addfield (lua_State *L, luaL_Buffer *b, int i) { |
85 | lua_rawgeti(L, 1, i); |
86 | if (!lua_isstring(L, -1)) |
87 | luaL_error(L, "invalid value (%s) at index %d in table for " |
88 | LUA_QL("concat"), luaL_typename(L, -1), i); |
89 | luaL_addvalue(b); |
90 | } |
91 | |
92 | |
93 | static int tconcat (lua_State *L) { |
94 | luaL_Buffer b; |
95 | size_t lsep; |
96 | int i, last; |
97 | const char *sep = luaL_optlstring(L, 2, "", &lsep); |
98 | luaL_checktype(L, 1, LUA_TTABLE); |
99 | i = luaL_optint(L, 3, 1); |
100 | last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1)); |
101 | luaL_buffinit(L, &b); |
102 | for (; i < last; i++) { |
103 | addfield(L, &b, i); |
104 | luaL_addlstring(&b, sep, lsep); |
105 | } |
106 | if (i == last) /* add last value (if interval was not empty) */ |
107 | addfield(L, &b, i); |
108 | luaL_pushresult(&b); |
109 | return 1; |
110 | } |
111 | |
112 | |
113 | /* |
114 | ** {====================================================== |
115 | ** Pack/unpack |
116 | ** ======================================================= |
117 | */ |
118 | |
119 | static int pack (lua_State *L) { |
120 | int n = lua_gettop(L); /* number of elements to pack */ |
121 | lua_createtable(L, n, 1); /* create result table */ |
122 | lua_pushinteger(L, n); |
123 | lua_setfield(L, -2, "n"); /* t.n = number of elements */ |
124 | if (n > 0) { /* at least one element? */ |
125 | int i; |
126 | lua_pushvalue(L, 1); |
127 | lua_rawseti(L, -2, 1); /* insert first element */ |
128 | lua_replace(L, 1); /* move table into index 1 */ |
129 | for (i = n; i >= 2; i--) /* assign other elements */ |
130 | lua_rawseti(L, 1, i); |
131 | } |
132 | return 1; /* return table */ |
133 | } |
134 | |
135 | |
136 | static int unpack (lua_State *L) { |
137 | int i, e, n; |
138 | luaL_checktype(L, 1, LUA_TTABLE); |
139 | i = luaL_optint(L, 2, 1); |
140 | e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1)); |
141 | if (i > e) return 0; /* empty range */ |
142 | n = e - i + 1; /* number of elements */ |
143 | if (n <= 0 || !lua_checkstack(L, n)) /* n <= 0 means arith. overflow */ |
144 | return luaL_error(L, "too many results to unpack"); |
145 | lua_rawgeti(L, 1, i); /* push arg[i] (avoiding overflow problems) */ |
146 | while (i++ < e) /* push arg[i + 1...e] */ |
147 | lua_rawgeti(L, 1, i); |
148 | return n; |
149 | } |
150 | |
151 | /* }====================================================== */ |
152 | |
153 | |
154 | |
155 | /* |
156 | ** {====================================================== |
157 | ** Quicksort |
158 | ** (based on `Algorithms in MODULA-3', Robert Sedgewick; |
159 | ** Addison-Wesley, 1993.) |
160 | ** ======================================================= |
161 | */ |
162 | |
163 | |
164 | static void set2 (lua_State *L, int i, int j) { |
165 | lua_rawseti(L, 1, i); |
166 | lua_rawseti(L, 1, j); |
167 | } |
168 | |
169 | static 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_compare(L, a, b, LUA_OPLT); |
182 | } |
183 | |
184 | static 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 | |
247 | static 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 | |
260 | static const luaL_Reg tab_funcs[] = { |
261 | {"concat", tconcat}, |
262 | #if defined(LUA_COMPAT_MAXN) |
263 | {"maxn", maxn}, |
264 | #endif |
265 | {"insert", tinsert}, |
266 | {"pack", pack}, |
267 | {"unpack", unpack}, |
268 | {"remove", tremove}, |
269 | {"sort", sort}, |
270 | {NULL, NULL} |
271 | }; |
272 | |
273 | |
274 | LUAMOD_API int luaopen_table (lua_State *L) { |
275 | luaL_newlib(L, tab_funcs); |
276 | #if defined(LUA_COMPAT_UNPACK) |
277 | /* _G.unpack = table.unpack */ |
278 | lua_getfield(L, -1, "unpack"); |
279 | lua_setglobal(L, "unpack"); |
280 | #endif |
281 | return 1; |
282 | } |
283 | |