The Battle for Wesnoth  1.15.12+dev
ltm.cpp
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1 /*
2 ** $Id: ltm.c $
3 ** Tag methods
4 ** See Copyright Notice in lua.h
5 */
6 
7 #define ltm_c
8 #define LUA_CORE
9 
10 #include "lprefix.h"
11 
12 
13 #include <string.h>
14 
15 #include "lua.h"
16 
17 #include "ldebug.h"
18 #include "ldo.h"
19 #include "lgc.h"
20 #include "lobject.h"
21 #include "lstate.h"
22 #include "lstring.h"
23 #include "ltable.h"
24 #include "ltm.h"
25 #include "lvm.h"
26 
27 
28 static const char udatatypename[] = "userdata";
29 
31  "no value",
32  "nil", "boolean", udatatypename, "number",
33  "string", "table", "function", udatatypename, "thread",
34  "upvalue", "proto" /* these last cases are used for tests only */
35 };
36 
37 
38 void luaT_init (lua_State *L) {
39  static const char *const luaT_eventname[] = { /* ORDER TM */
40  "__index", "__newindex",
41  "__gc", "__mode", "__len", "__eq",
42  "__add", "__sub", "__mul", "__mod", "__pow",
43  "__div", "__idiv",
44  "__band", "__bor", "__bxor", "__shl", "__shr",
45  "__unm", "__bnot", "__lt", "__le",
46  "__concat", "__call", "__close"
47  };
48  int i;
49  for (i=0; i<TM_N; i++) {
50  G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
51  luaC_fix(L, obj2gco(G(L)->tmname[i])); /* never collect these names */
52  }
53 }
54 
55 
56 /*
57 ** function to be used with macro "fasttm": optimized for absence of
58 ** tag methods
59 */
60 const TValue *luaT_gettm (Table *events, TMS event, TString *ename) {
61  const TValue *tm = luaH_getshortstr(events, ename);
62  lua_assert(event <= TM_EQ);
63  if (notm(tm)) { /* no tag method? */
64  events->flags |= cast_byte(1u<<event); /* cache this fact */
65  return NULL;
66  }
67  else return tm;
68 }
69 
70 
71 const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) {
72  Table *mt;
73  switch (ttype(o)) {
74  case LUA_TTABLE:
75  mt = hvalue(o)->metatable;
76  break;
77  case LUA_TUSERDATA:
78  mt = uvalue(o)->metatable;
79  break;
80  default:
81  mt = G(L)->mt[ttype(o)];
82  }
83  return (mt ? luaH_getshortstr(mt, G(L)->tmname[event]) : &G(L)->nilvalue);
84 }
85 
86 
87 /*
88 ** Return the name of the type of an object. For tables and userdata
89 ** with metatable, use their '__name' metafield, if present.
90 */
91 const char *luaT_objtypename (lua_State *L, const TValue *o) {
92  Table *mt;
93  if ((ttistable(o) && (mt = hvalue(o)->metatable) != NULL) ||
94  (ttisfulluserdata(o) && (mt = uvalue(o)->metatable) != NULL)) {
95  const TValue *name = luaH_getshortstr(mt, luaS_new(L, "__name"));
96  if (ttisstring(name)) /* is '__name' a string? */
97  return getstr(tsvalue(name)); /* use it as type name */
98  }
99  return ttypename(ttype(o)); /* else use standard type name */
100 }
101 
102 
103 void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1,
104  const TValue *p2, const TValue *p3) {
105  StkId func = L->top;
106  setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */
107  setobj2s(L, func + 1, p1); /* 1st argument */
108  setobj2s(L, func + 2, p2); /* 2nd argument */
109  setobj2s(L, func + 3, p3); /* 3rd argument */
110  L->top = func + 4;
111  /* metamethod may yield only when called from Lua code */
112  if (isLuacode(L->ci))
113  luaD_call(L, func, 0);
114  else
115  luaD_callnoyield(L, func, 0);
116 }
117 
118 
119 void luaT_callTMres (lua_State *L, const TValue *f, const TValue *p1,
120  const TValue *p2, StkId res) {
121  ptrdiff_t result = savestack(L, res);
122  StkId func = L->top;
123  setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */
124  setobj2s(L, func + 1, p1); /* 1st argument */
125  setobj2s(L, func + 2, p2); /* 2nd argument */
126  L->top += 3;
127  /* metamethod may yield only when called from Lua code */
128  if (isLuacode(L->ci))
129  luaD_call(L, func, 1);
130  else
131  luaD_callnoyield(L, func, 1);
132  res = restorestack(L, result);
133  setobjs2s(L, res, --L->top); /* move result to its place */
134 }
135 
136 
137 static int callbinTM (lua_State *L, const TValue *p1, const TValue *p2,
138  StkId res, TMS event) {
139  const TValue *tm = luaT_gettmbyobj(L, p1, event); /* try first operand */
140  if (notm(tm))
141  tm = luaT_gettmbyobj(L, p2, event); /* try second operand */
142  if (notm(tm)) return 0;
143  luaT_callTMres(L, tm, p1, p2, res);
144  return 1;
145 }
146 
147 
148 void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2,
149  StkId res, TMS event) {
150  if (!callbinTM(L, p1, p2, res, event)) {
151  switch (event) {
152  case TM_BAND: case TM_BOR: case TM_BXOR:
153  case TM_SHL: case TM_SHR: case TM_BNOT: {
154  if (ttisnumber(p1) && ttisnumber(p2))
155  luaG_tointerror(L, p1, p2);
156  else
157  luaG_opinterror(L, p1, p2, "perform bitwise operation on");
158  }
159  /* calls never return, but to avoid warnings: *//* FALLTHROUGH */
160  default:
161  luaG_opinterror(L, p1, p2, "perform arithmetic on");
162  }
163  }
164 }
165 
166 
168  StkId top = L->top;
169  if (!callbinTM(L, s2v(top - 2), s2v(top - 1), top - 2, TM_CONCAT))
170  luaG_concaterror(L, s2v(top - 2), s2v(top - 1));
171 }
172 
173 
174 void luaT_trybinassocTM (lua_State *L, const TValue *p1, const TValue *p2,
175  int flip, StkId res, TMS event) {
176  if (flip)
177  luaT_trybinTM(L, p2, p1, res, event);
178  else
179  luaT_trybinTM(L, p1, p2, res, event);
180 }
181 
182 
183 void luaT_trybiniTM (lua_State *L, const TValue *p1, lua_Integer i2,
184  int flip, StkId res, TMS event) {
185  TValue aux;
186  setivalue(&aux, i2);
187  luaT_trybinassocTM(L, p1, &aux, flip, res, event);
188 }
189 
190 
191 /*
192 ** Calls an order tag method.
193 ** For lessequal, LUA_COMPAT_LT_LE keeps compatibility with old
194 ** behavior: if there is no '__le', try '__lt', based on l <= r iff
195 ** !(r < l) (assuming a total order). If the metamethod yields during
196 ** this substitution, the continuation has to know about it (to negate
197 ** the result of r<l); bit CIST_LEQ in the call status keeps that
198 ** information.
199 */
200 int luaT_callorderTM (lua_State *L, const TValue *p1, const TValue *p2,
201  TMS event) {
202  if (callbinTM(L, p1, p2, L->top, event)) /* try original event */
203  return !l_isfalse(s2v(L->top));
204 #if defined(LUA_COMPAT_LT_LE)
205  else if (event == TM_LE) {
206  /* try '!(p2 < p1)' for '(p1 <= p2)' */
207  L->ci->callstatus |= CIST_LEQ; /* mark it is doing 'lt' for 'le' */
208  if (callbinTM(L, p2, p1, L->top, TM_LT)) {
209  L->ci->callstatus ^= CIST_LEQ; /* clear mark */
210  return l_isfalse(s2v(L->top));
211  }
212  /* else error will remove this 'ci'; no need to clear mark */
213  }
214 #endif
215  luaG_ordererror(L, p1, p2); /* no metamethod found */
216  return 0; /* to avoid warnings */
217 }
218 
219 
220 int luaT_callorderiTM (lua_State *L, const TValue *p1, int v2,
221  int flip, int isfloat, TMS event) {
222  TValue aux; const TValue *p2;
223  if (isfloat) {
224  setfltvalue(&aux, cast_num(v2));
225  }
226  else
227  setivalue(&aux, v2);
228  if (flip) { /* arguments were exchanged? */
229  p2 = p1; p1 = &aux; /* correct them */
230  }
231  else
232  p2 = &aux;
233  return luaT_callorderTM(L, p1, p2, event);
234 }
235 
236 
237 void luaT_adjustvarargs (lua_State *L, int nfixparams, CallInfo *ci,
238  const Proto *p) {
239  int i;
240  int actual = cast_int(L->top - ci->func) - 1; /* number of arguments */
241  int nextra = actual - nfixparams; /* number of extra arguments */
242  ci->u.l.nextraargs = nextra;
243  luaD_checkstack(L, p->maxstacksize + 1);
244  /* copy function to the top of the stack */
245  setobjs2s(L, L->top++, ci->func);
246  /* move fixed parameters to the top of the stack */
247  for (i = 1; i <= nfixparams; i++) {
248  setobjs2s(L, L->top++, ci->func + i);
249  setnilvalue(s2v(ci->func + i)); /* erase original parameter (for GC) */
250  }
251  ci->func += actual + 1;
252  ci->top += actual + 1;
253  lua_assert(L->top <= ci->top && ci->top <= L->stack_last);
254 }
255 
256 
257 void luaT_getvarargs (lua_State *L, CallInfo *ci, StkId where, int wanted) {
258  int i;
259  int nextra = ci->u.l.nextraargs;
260  if (wanted < 0) {
261  wanted = nextra; /* get all extra arguments available */
262  checkstackGCp(L, nextra, where); /* ensure stack space */
263  L->top = where + nextra; /* next instruction will need top */
264  }
265  for (i = 0; i < wanted && i < nextra; i++)
266  setobjs2s(L, where + i, ci->func - nextra + i);
267  for (; i < wanted; i++) /* complete required results with nil */
268  setnilvalue(s2v(where + i));
269 }
270 
unsigned short callstatus
Definition: lstate.h:185
Definition: ltm.h:41
#define ttistable(o)
Definition: lobject.h:657
#define cast_num(i)
Definition: llimits.h:127
Definition: ltm.h:34
#define s2v(o)
Definition: lobject.h:150
Definition: lobject.h:714
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Definition: lstate.h:347
void luaT_trybiniTM(lua_State *L, const TValue *p1, lua_Integer i2, int flip, StkId res, TMS event)
Definition: ltm.cpp:183
#define LUA_TUSERDATA
Definition: lua.h:72
Definition: lobject.h:530
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Definition: lobject.h:341
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Definition: lobject.h:412
Definition: ltm.h:33
Definition: ltm.h:35
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Definition: lstate.h:162
Definition: lobject.h:65
void luaT_trybinTM(lua_State *L, const TValue *p1, const TValue *p2, StkId res, TMS event)
Definition: ltm.cpp:148
#define cast_byte(i)
Definition: llimits.h:130
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#define uvalue(o)
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Definition: lstate.h:209
Definition: ltm.h:38
const TValue * luaH_getshortstr(Table *t, TString *key)
Definition: ltable.cpp:725
void luaT_trybinassocTM(lua_State *L, const TValue *p1, const TValue *p2, int flip, StkId res, TMS event)
Definition: ltm.cpp:174
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Definition: lstring.cpp:241
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Definition: lstate.h:278
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Definition: lstate.h:281
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Definition: ldo.h:36
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Definition: ltm.cpp:28
LUA_INTEGER lua_Integer
Definition: lua.h:94
#define getstr(ts)
Definition: lobject.h:381
void luaT_callTMres(lua_State *L, const TValue *f, const TValue *p1, const TValue *p2, StkId res)
Definition: ltm.cpp:119
CallInfo * ci
Definition: lstate.h:280
#define LUAI_DDEF
Definition: luaconf.h:311
const char * luaT_objtypename(lua_State *L, const TValue *o)
Definition: ltm.cpp:91
void luaT_init(lua_State *L)
Definition: ltm.cpp:38
void luaT_tryconcatTM(lua_State *L)
Definition: ltm.cpp:167
Definition: ltm.h:44
#define luaD_checkstack(L, n)
Definition: ldo.h:31
static int callbinTM(lua_State *L, const TValue *p1, const TValue *p2, StkId res, TMS event)
Definition: ltm.cpp:137
StkId func
Definition: lstate.h:161
void luaT_callTM(lua_State *L, const TValue *f, const TValue *p1, const TValue *p2, const TValue *p3)
Definition: ltm.cpp:103
LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTYPES]
Definition: ltm.cpp:30
Definition: ltm.h:39
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Definition: ldo.h:40
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Definition: ldebug.cpp:731
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Definition: lobject.h:534
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Definition: ltm.cpp:71
#define tsvalue(o)
Definition: lobject.h:347
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Definition: lgc.cpp:243
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Definition: lobject.h:322
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Definition: ltm.h:69
Definition: ltm.h:36
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Definition: ltm.cpp:200
Definition: ltm.h:32
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Definition: ldebug.cpp:723
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Definition: lobject.h:316
l_noret luaG_opinterror(lua_State *L, const TValue *p1, const TValue *p2, const char *msg)
Definition: ldebug.cpp:712
lu_byte flags
Definition: lobject.h:716
union CallInfo::@13 u
void luaT_getvarargs(lua_State *L, CallInfo *ci, StkId where, int wanted)
Definition: ltm.cpp:257
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Definition: ldo.cpp:557
struct CallInfo::@13::@15 l
Definition: ltm.h:24
Handling of system events.
Definition: manager.hpp:42
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Definition: ldo.cpp:565
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Definition: ldo.h:35
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Definition: lobject.h:304
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Definition: ltm.cpp:237
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Definition: ltm.h:18
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Definition: lobject.h:85
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Definition: ldebug.cpp:706
Definition: ltm.h:40
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Definition: llimits.h:128
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Definition: lobject.h:127
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Definition: ltm.h:61
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Definition: lobject.h:225
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Definition: lobject.h:31
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Definition: ltm.cpp:60
#define LUA_TTABLE
Definition: lua.h:70
int luaT_callorderiTM(lua_State *L, const TValue *p1, int v2, int flip, int isfloat, TMS event)
Definition: ltm.cpp:220
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Definition: lobject.h:659