source: trunk/src/lua/ltablib.c @ 2542

Last change on this file since 2542 was 2542, checked in by sam, 10 years ago

lua: compilation fixes for non-quite-POSIX platforms.

File size: 7.5 KB
Line 
1/*
2** $Id: ltablib.c,v 1.63 2011/11/28 17:26:30 roberto Exp $
3** Library for Table Manipulation
4** See Copyright Notice in lua.h
5*/
6
7#if defined HAVE_CONFIG_H // LOL BEGIN
8#   include "config.h"
9#endif // LOL END
10
11#include <stddef.h>
12
13#define ltablib_c
14#define LUA_LIB
15
16#include "lua.h"
17
18#include "lauxlib.h"
19#include "lualib.h"
20
21
22#define aux_getn(L,n)  \
23        (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n))
24
25
26#if defined(LUA_COMPAT_MAXN)
27static int maxn (lua_State *L) {
28  lua_Number max = 0;
29  luaL_checktype(L, 1, LUA_TTABLE);
30  lua_pushnil(L);  /* first key */
31  while (lua_next(L, 1)) {
32    lua_pop(L, 1);  /* remove value */
33    if (lua_type(L, -1) == LUA_TNUMBER) {
34      lua_Number v = lua_tonumber(L, -1);
35      if (v > max) max = v;
36    }
37  }
38  lua_pushnumber(L, max);
39  return 1;
40}
41#endif
42
43
44static int tinsert (lua_State *L) {
45  int e = aux_getn(L, 1) + 1;  /* first empty element */
46  int pos;  /* where to insert new element */
47  switch (lua_gettop(L)) {
48    case 2: {  /* called with only 2 arguments */
49      pos = e;  /* insert new element at the end */
50      break;
51    }
52    case 3: {
53      int i;
54      pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
55      if (pos > e) e = pos;  /* `grow' array if necessary */
56      for (i = e; i > pos; i--) {  /* move up elements */
57        lua_rawgeti(L, 1, i-1);
58        lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
59      }
60      break;
61    }
62    default: {
63      return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
64    }
65  }
66  lua_rawseti(L, 1, pos);  /* t[pos] = v */
67  return 0;
68}
69
70
71static int tremove (lua_State *L) {
72  int e = aux_getn(L, 1);
73  int pos = luaL_optint(L, 2, e);
74  if (!(1 <= pos && pos <= e))  /* position is outside bounds? */
75    return 0;  /* nothing to remove */
76  lua_rawgeti(L, 1, pos);  /* result = t[pos] */
77  for ( ;pos<e; pos++) {
78    lua_rawgeti(L, 1, pos+1);
79    lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
80  }
81  lua_pushnil(L);
82  lua_rawseti(L, 1, e);  /* t[e] = nil */
83  return 1;
84}
85
86
87static void addfield (lua_State *L, luaL_Buffer *b, int i) {
88  lua_rawgeti(L, 1, i);
89  if (!lua_isstring(L, -1))
90    luaL_error(L, "invalid value (%s) at index %d in table for "
91                  LUA_QL("concat"), luaL_typename(L, -1), i);
92  luaL_addvalue(b);
93}
94
95
96static int tconcat (lua_State *L) {
97  luaL_Buffer b;
98  size_t lsep;
99  int i, last;
100  const char *sep = luaL_optlstring(L, 2, "", &lsep);
101  luaL_checktype(L, 1, LUA_TTABLE);
102  i = luaL_optint(L, 3, 1);
103  last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1));
104  luaL_buffinit(L, &b);
105  for (; i < last; i++) {
106    addfield(L, &b, i);
107    luaL_addlstring(&b, sep, lsep);
108  }
109  if (i == last)  /* add last value (if interval was not empty) */
110    addfield(L, &b, i);
111  luaL_pushresult(&b);
112  return 1;
113}
114
115
116/*
117** {======================================================
118** Pack/unpack
119** =======================================================
120*/
121
122static int pack (lua_State *L) {
123  int n = lua_gettop(L);  /* number of elements to pack */
124  lua_createtable(L, n, 1);  /* create result table */
125  lua_pushinteger(L, n);
126  lua_setfield(L, -2, "n");  /* t.n = number of elements */
127  if (n > 0) {  /* at least one element? */
128    int i;
129    lua_pushvalue(L, 1);
130    lua_rawseti(L, -2, 1);  /* insert first element */
131    lua_replace(L, 1);  /* move table into index 1 */
132    for (i = n; i >= 2; i--)  /* assign other elements */
133      lua_rawseti(L, 1, i);
134  }
135  return 1;  /* return table */
136}
137
138
139static int unpack (lua_State *L) {
140  int i, e, n;
141  luaL_checktype(L, 1, LUA_TTABLE);
142  i = luaL_optint(L, 2, 1);
143  e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
144  if (i > e) return 0;  /* empty range */
145  n = e - i + 1;  /* number of elements */
146  if (n <= 0 || !lua_checkstack(L, n))  /* n <= 0 means arith. overflow */
147    return luaL_error(L, "too many results to unpack");
148  lua_rawgeti(L, 1, i);  /* push arg[i] (avoiding overflow problems) */
149  while (i++ < e)  /* push arg[i + 1...e] */
150    lua_rawgeti(L, 1, i);
151  return n;
152}
153
154/* }====================================================== */
155
156
157
158/*
159** {======================================================
160** Quicksort
161** (based on `Algorithms in MODULA-3', Robert Sedgewick;
162**  Addison-Wesley, 1993.)
163** =======================================================
164*/
165
166
167static void set2 (lua_State *L, int i, int j) {
168  lua_rawseti(L, 1, i);
169  lua_rawseti(L, 1, j);
170}
171
172static int sort_comp (lua_State *L, int a, int b) {
173  if (!lua_isnil(L, 2)) {  /* function? */
174    int res;
175    lua_pushvalue(L, 2);
176    lua_pushvalue(L, a-1);  /* -1 to compensate function */
177    lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
178    lua_call(L, 2, 1);
179    res = lua_toboolean(L, -1);
180    lua_pop(L, 1);
181    return res;
182  }
183  else  /* a < b? */
184    return lua_compare(L, a, b, LUA_OPLT);
185}
186
187static void auxsort (lua_State *L, int l, int u) {
188  while (l < u) {  /* for tail recursion */
189    int i, j;
190    /* sort elements a[l], a[(l+u)/2] and a[u] */
191    lua_rawgeti(L, 1, l);
192    lua_rawgeti(L, 1, u);
193    if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
194      set2(L, l, u);  /* swap a[l] - a[u] */
195    else
196      lua_pop(L, 2);
197    if (u-l == 1) break;  /* only 2 elements */
198    i = (l+u)/2;
199    lua_rawgeti(L, 1, i);
200    lua_rawgeti(L, 1, l);
201    if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
202      set2(L, i, l);
203    else {
204      lua_pop(L, 1);  /* remove a[l] */
205      lua_rawgeti(L, 1, u);
206      if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
207        set2(L, i, u);
208      else
209        lua_pop(L, 2);
210    }
211    if (u-l == 2) break;  /* only 3 elements */
212    lua_rawgeti(L, 1, i);  /* Pivot */
213    lua_pushvalue(L, -1);
214    lua_rawgeti(L, 1, u-1);
215    set2(L, i, u-1);
216    /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
217    i = l; j = u-1;
218    for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
219      /* repeat ++i until a[i] >= P */
220      while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
221        if (i>=u) luaL_error(L, "invalid order function for sorting");
222        lua_pop(L, 1);  /* remove a[i] */
223      }
224      /* repeat --j until a[j] <= P */
225      while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
226        if (j<=l) luaL_error(L, "invalid order function for sorting");
227        lua_pop(L, 1);  /* remove a[j] */
228      }
229      if (j<i) {
230        lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
231        break;
232      }
233      set2(L, i, j);
234    }
235    lua_rawgeti(L, 1, u-1);
236    lua_rawgeti(L, 1, i);
237    set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
238    /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
239    /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
240    if (i-l < u-i) {
241      j=l; i=i-1; l=i+2;
242    }
243    else {
244      j=i+1; i=u; u=j-2;
245    }
246    auxsort(L, j, i);  /* call recursively the smaller one */
247  }  /* repeat the routine for the larger one */
248}
249
250static int sort (lua_State *L) {
251  int n = aux_getn(L, 1);
252  luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
253  if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
254    luaL_checktype(L, 2, LUA_TFUNCTION);
255  lua_settop(L, 2);  /* make sure there is two arguments */
256  auxsort(L, 1, n);
257  return 0;
258}
259
260/* }====================================================== */
261
262
263static const luaL_Reg tab_funcs[] = {
264  {"concat", tconcat},
265#if defined(LUA_COMPAT_MAXN)
266  {"maxn", maxn},
267#endif
268  {"insert", tinsert},
269  {"pack", pack},
270  {"unpack", unpack},
271  {"remove", tremove},
272  {"sort", sort},
273  {NULL, NULL}
274};
275
276
277LUAMOD_API int luaopen_table (lua_State *L) {
278  luaL_newlib(L, tab_funcs);
279#if defined(LUA_COMPAT_UNPACK)
280  /* _G.unpack = table.unpack */
281  lua_getfield(L, -1, "unpack");
282  lua_setglobal(L, "unpack");
283#endif
284  return 1;
285}
286
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