diff options
Diffstat (limited to 'src/lua/ltm.c')
| -rw-r--r-- | src/lua/ltm.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/lua/ltm.c b/src/lua/ltm.c new file mode 100644 index 00000000..3f69a6ca --- /dev/null +++ b/src/lua/ltm.c @@ -0,0 +1,163 @@ +/* +** $Id: ltm.c,v 1.3 2001/11/26 23:00:26 darkgod Exp $ +** Tag methods +** See Copyright Notice in lua.h +*/ + + +#include <stdio.h> +#include <string.h> + +#include "lua.h" + +#include "ldo.h" +#include "lmem.h" +#include "lobject.h" +#include "lstate.h" +#include "ltm.h" + + +const char *const luaT_eventname[] = { /* ORDER TM */ + "gettable", "settable", "index", "getglobal", "setglobal", "add", "sub", + "mul", "div", "pow", "unm", "lt", "concat", "gc", "function", + "le", "gt", "ge", /* deprecated options!! */ + NULL +}; + + +static int findevent (const char *name) { + int i; + for (i=0; luaT_eventname[i]; i++) + if (strcmp(luaT_eventname[i], name) == 0) + return i; + return -1; /* name not found */ +} + + +static int luaI_checkevent (lua_State *L, const char *name, int t) { + int e = findevent(name); + if (e >= TM_N) + luaO_verror(L, "event `%.50s' is deprecated", name); + if (e == TM_GC && t == LUA_TTABLE) + luaO_verror(L, "event `gc' for tables is deprecated"); + if (e < 0) + luaO_verror(L, "`%.50s' is not a valid event name", name); + return e; +} + + + +/* events in LUA_TNIL are all allowed, since this is used as a +* 'placeholder' for "default" fallbacks +*/ +/* ORDER LUA_T, ORDER TM */ +static const char luaT_validevents[NUM_TAGS][TM_N] = { + {1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TUSERDATA */ + {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* LUA_TNIL */ + {1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1}, /* LUA_TNUMBER */ + {1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_TSTRING */ + {0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TTABLE */ + {1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0} /* LUA_TFUNCTION */ +}; + +int luaT_validevent (int t, int e) { /* ORDER LUA_T */ + return (t >= NUM_TAGS) ? 1 : luaT_validevents[t][e]; +} + + +static void init_entry (lua_State *L, int tag) { + int i; + for (i=0; i<TM_N; i++) + luaT_gettm(L, tag, i) = NULL; + L->TMtable[tag].collected = NULL; +} + + +void luaT_init (lua_State *L) { + int t; + luaM_growvector(L, L->TMtable, 0, NUM_TAGS, struct TM, "", MAX_INT); + L->nblocks += NUM_TAGS*sizeof(struct TM); + L->last_tag = NUM_TAGS-1; + for (t=0; t<=L->last_tag; t++) + init_entry(L, t); +} + + +LUA_API int lua_newtag (lua_State *L) { + luaM_growvector(L, L->TMtable, L->last_tag, 1, struct TM, + "tag table overflow", MAX_INT); + L->nblocks += sizeof(struct TM); + L->last_tag++; + init_entry(L, L->last_tag); + return L->last_tag; +} + + +static void checktag (lua_State *L, int tag) { + if (!(0 <= tag && tag <= L->last_tag)) + luaO_verror(L, "%d is not a valid tag", tag); +} + +void luaT_realtag (lua_State *L, int tag) { + if (!validtag(tag)) + luaO_verror(L, "tag %d was not created by `newtag'", tag); +} + + +LUA_API int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) { + int e; + checktag(L, tagto); + checktag(L, tagfrom); + for (e=0; e<TM_N; e++) { + if (luaT_validevent(tagto, e)) + luaT_gettm(L, tagto, e) = luaT_gettm(L, tagfrom, e); + } + return tagto; +} + + +int luaT_tag (const TObject *o) { + int t = ttype(o); + switch (t) { + case LUA_TUSERDATA: return tsvalue(o)->u.d.tag; + case LUA_TTABLE: return hvalue(o)->htag; + default: return t; + } +} + + +LUA_API void lua_gettagmethod (lua_State *L, int t, const char *event) { + int e; + e = luaI_checkevent(L, event, t); + checktag(L, t); + if (luaT_validevent(t, e) && luaT_gettm(L, t, e)) { + clvalue(L->top) = luaT_gettm(L, t, e); + ttype(L->top) = LUA_TFUNCTION; + } + else + ttype(L->top) = LUA_TNIL; + incr_top; +} + + +LUA_API void lua_settagmethod (lua_State *L, int t, const char *event) { + int e = luaI_checkevent(L, event, t); + checktag(L, t); + if (!luaT_validevent(t, e)) + luaO_verror(L, "cannot change `%.20s' tag method for type `%.20s'%.20s", + luaT_eventname[e], luaO_typenames[t], + (t == LUA_TTABLE || t == LUA_TUSERDATA) ? + " with default tag" : ""); + switch (ttype(L->top - 1)) { + case LUA_TNIL: + luaT_gettm(L, t, e) = NULL; + break; + case LUA_TFUNCTION: + luaT_gettm(L, t, e) = clvalue(L->top - 1); + break; + default: + lua_error(L, "tag method must be a function (or nil)"); + } + L->top--; +} + |