static int str_byte (lua_State *L) { size_t l; const char *s = luaL_checklstring(L, 1, &l); ptrdiff_t posi = posrelat(luaL_optint32(L, 2, 1), l); ptrdiff_t pose = posrelat(luaL_optint32(L, 3, posi), l); int n, i; if (posi <= 0) posi = 1; if ((size_t)pose > l) pose = l; if (posi > pose) return 0; /* empty interval; return no values */ n = (int)(pose - posi + 1); if (posi + n <= pose) /* overflow? */ luaL_error(L, "string slice too long"); luaL_checkstack(L, n, "string slice too long"); for (i=0; i<n; i++) lua_pushinteger(L, uchar(s[posi+i-1])); return n; }
static int f_setvbuf (lua_State *L) { static const int mode[] = {_IONBF, _IOFBF, _IOLBF}; static const char *const modenames[] = {"no", "full", "line", NULL}; FILE *f = tofile(L); int op = luaL_checkoption(L, 2, NULL, modenames); size_t sz = luaL_optint32(L, 3, LUAL_BUFFERSIZE); int res = setvbuf(f, NULL, mode[op], sz); return pushresult(L, res == 0, NULL); }
static int str_sub (lua_State *L) { size_t l; const char *s = luaL_checklstring(L, 1, &l); ptrdiff_t start = posrelat(luaL_checkint32(L, 2), l); ptrdiff_t end = posrelat(luaL_optint32(L, 3, -1), l); if (start < 1) start = 1; if (end > (ptrdiff_t)l) end = (ptrdiff_t)l; if (start <= end) lua_pushlstring(L, s+start-1, end-start+1); else lua_pushliteral(L, ""); return 1; }
static int str_find_aux (lua_State *L, int find) { size_t l1, l2; const char *s = luaL_checklstring(L, 1, &l1); const char *p = luaL_checklstring(L, 2, &l2); ptrdiff_t init = posrelat(luaL_optint32(L, 3, 1), l1) - 1; if (init < 0) init = 0; else if ((size_t)(init) > l1) init = (ptrdiff_t)l1; if (find && (lua_toboolean(L, 4) || /* explicit request? */ strpbrk(p, SPECIALS) == NULL)) { /* or no special characters? */ /* do a plain search */ const char *s2 = lmemfind(s+init, l1-init, p, l2); if (s2) { lua_pushinteger(L, s2-s+1); lua_pushinteger(L, s2-s+l2); return 2; } } else { MatchState ms; int anchor = (*p == '^') ? (p++, 1) : 0; const char *s1=s+init; ms.L = L; ms.src_init = s; ms.src_end = s+l1; do { const char *res; ms.level = 0; if ((res=match(&ms, s1, p)) != NULL) { if (find) { lua_pushinteger(L, s1-s+1); /* start */ lua_pushinteger(L, res-s); /* end */ return push_captures(&ms, NULL, 0) + 2; } else return push_captures(&ms, s1, res); } } while (s1++ < ms.src_end && !anchor); } lua_pushnil(L); /* not found */ return 1; }