xref: /illumos-gate/usr/src/uts/common/fs/zfs/lua/ltablib.c (revision dfc115332c94a2f62058ac7f2bce7631fbd20b3d)
1 /*
2 ** $Id: ltablib.c,v 1.65.1.2 2014/05/07 16:32:55 roberto Exp $
3 ** Library for Table Manipulation
4 ** See Copyright Notice in lua.h
5 */
6 
7 
8 #include <sys/zfs_context.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)
maxn(lua_State * L)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 
tinsert(lua_State * L)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 
tremove(lua_State * L)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 
addfield(lua_State * L,luaL_Buffer * b,int i)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 
tconcat(lua_State * L)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 
pack(lua_State * L)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 
unpack(lua_State * L)136 static int unpack (lua_State *L) {
137   int i, e;
138   unsigned int n;
139   luaL_checktype(L, 1, LUA_TTABLE);
140   i = luaL_optint(L, 2, 1);
141   e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
142   if (i > e) return 0;  /* empty range */
143   n = (unsigned int)e - (unsigned int)i;  /* number of elements minus 1 */
144   if (n > (INT_MAX - 10) || !lua_checkstack(L, ++n))
145     return luaL_error(L, "too many results to unpack");
146   lua_rawgeti(L, 1, i);  /* push arg[i] (avoiding overflow problems) */
147   while (i++ < e)  /* push arg[i + 1...e] */
148     lua_rawgeti(L, 1, i);
149   return n;
150 }
151 
152 /* }====================================================== */
153 
154 
155 
156 /*
157 ** {======================================================
158 ** Quicksort
159 ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
160 **  Addison-Wesley, 1993.)
161 ** =======================================================
162 */
163 
164 
set2(lua_State * L,int i,int j)165 static void set2 (lua_State *L, int i, int j) {
166   lua_rawseti(L, 1, i);
167   lua_rawseti(L, 1, j);
168 }
169 
sort_comp(lua_State * L,int a,int b)170 static int sort_comp (lua_State *L, int a, int b) {
171   if (!lua_isnil(L, 2)) {  /* function? */
172     int res;
173     lua_pushvalue(L, 2);
174     lua_pushvalue(L, a-1);  /* -1 to compensate function */
175     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
176     lua_call(L, 2, 1);
177     res = lua_toboolean(L, -1);
178     lua_pop(L, 1);
179     return res;
180   }
181   else  /* a < b? */
182     return lua_compare(L, a, b, LUA_OPLT);
183 }
184 
auxsort(lua_State * L,int l,int u)185 static void auxsort (lua_State *L, int l, int u) {
186   while (l < u) {  /* for tail recursion */
187     int i, j;
188     /* sort elements a[l], a[(l+u)/2] and a[u] */
189     lua_rawgeti(L, 1, l);
190     lua_rawgeti(L, 1, u);
191     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
192       set2(L, l, u);  /* swap a[l] - a[u] */
193     else
194       lua_pop(L, 2);
195     if (u-l == 1) break;  /* only 2 elements */
196     i = (l+u)/2;
197     lua_rawgeti(L, 1, i);
198     lua_rawgeti(L, 1, l);
199     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
200       set2(L, i, l);
201     else {
202       lua_pop(L, 1);  /* remove a[l] */
203       lua_rawgeti(L, 1, u);
204       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
205         set2(L, i, u);
206       else
207         lua_pop(L, 2);
208     }
209     if (u-l == 2) break;  /* only 3 elements */
210     lua_rawgeti(L, 1, i);  /* Pivot */
211     lua_pushvalue(L, -1);
212     lua_rawgeti(L, 1, u-1);
213     set2(L, i, u-1);
214     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
215     i = l; j = u-1;
216     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
217       /* repeat ++i until a[i] >= P */
218       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
219         if (i>=u) luaL_error(L, "invalid order function for sorting");
220         lua_pop(L, 1);  /* remove a[i] */
221       }
222       /* repeat --j until a[j] <= P */
223       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
224         if (j<=l) luaL_error(L, "invalid order function for sorting");
225         lua_pop(L, 1);  /* remove a[j] */
226       }
227       if (j<i) {
228         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
229         break;
230       }
231       set2(L, i, j);
232     }
233     lua_rawgeti(L, 1, u-1);
234     lua_rawgeti(L, 1, i);
235     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
236     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
237     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
238     if (i-l < u-i) {
239       j=l; i=i-1; l=i+2;
240     }
241     else {
242       j=i+1; i=u; u=j-2;
243     }
244     auxsort(L, j, i);  /* call recursively the smaller one */
245   }  /* repeat the routine for the larger one */
246 }
247 
sort(lua_State * L)248 static int sort (lua_State *L) {
249   int n = aux_getn(L, 1);
250   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
251   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
252     luaL_checktype(L, 2, LUA_TFUNCTION);
253   lua_settop(L, 2);  /* make sure there is two arguments */
254   auxsort(L, 1, n);
255   return 0;
256 }
257 
258 /* }====================================================== */
259 
260 
261 static const luaL_Reg tab_funcs[] = {
262   {"concat", tconcat},
263 #if defined(LUA_COMPAT_MAXN)
264   {"maxn", maxn},
265 #endif
266   {"insert", tinsert},
267   {"pack", pack},
268   {"unpack", unpack},
269   {"remove", tremove},
270   {"sort", sort},
271   {NULL, NULL}
272 };
273 
274 
luaopen_table(lua_State * L)275 LUAMOD_API int luaopen_table (lua_State *L) {
276   luaL_newlib(L, tab_funcs);
277 #if defined(LUA_COMPAT_UNPACK)
278   /* _G.unpack = table.unpack */
279   lua_getfield(L, -1, "unpack");
280   lua_setglobal(L, "unpack");
281 #endif
282   return 1;
283 }
284 
285