diff --git a/lvm.c b/lvm.c index 93cb8bc8..dc479f0a 100644 --- a/lvm.c +++ b/lvm.c @@ -80,6 +80,21 @@ #endif +/* +** Try to convert a value from string to a number value. +** If the value is not a string or is a string not representing +** a valid numeral (or if coercions from strings to numbers +** are disabled via macro 'cvt2num'), do not modify 'result' +** and return 0. +*/ +static int l_strton (const TValue *obj, TValue *result) { + lua_assert(obj != result); + if (!cvt2num(obj)) /* is object not a string? */ + return 0; + else + return (luaO_str2num(svalue(obj), result) == vslen(obj) + 1); +} + /* ** Try to convert a value to a float. The float case is already handled @@ -91,8 +106,7 @@ int luaV_tonumber_ (const TValue *obj, lua_Number *n) { *n = cast_num(ivalue(obj)); return 1; } - else if (cvt2num(obj) && /* string coercible to number? */ - luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) { + else if (l_strton(obj, &v)) { /* string coercible to number? */ *n = nvalue(&v); /* convert result of 'luaO_str2num' to a float */ return 1; } @@ -111,7 +125,7 @@ int luaV_flttointeger (lua_Number n, lua_Integer *p, int mode) { lua_Number f = l_floor(n); if (n != f) { /* not an integral value? */ if (mode == 0) return 0; /* fails if mode demands integral value */ - else if (mode > 1) /* needs ceil? */ + else if (mode == 2) /* needs ceil? */ f += 1; /* convert floor to ceil (remember: n != f) */ } return lua_numbertointeger(f, p); @@ -140,27 +154,27 @@ int luaV_tointegerns (const TValue *obj, lua_Integer *p, int mode) { */ int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode) { TValue v; - if (cvt2num(obj) && luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) - obj = &v; /* change string to its corresponding number */ + if (l_strton(obj, &v)) /* does 'obj' point to a numerical string? */ + obj = &v; /* change it to point to its corresponding number */ return luaV_tointegerns(obj, p, mode); } /* ** Try to convert a 'for' limit to an integer, preserving the semantics -** of the loop. (The following explanation assumes a positive step; -** it is valid for negative steps mutatis mutandis.) -** Return true if the loop must not run. +** of the loop. Return true if the loop must not run; otherwise, '*p' +** gets the integer limit. +** (The following explanation assumes a positive step; it is valid for +** negative steps mutatis mutandis.) ** If the limit is an integer or can be converted to an integer, ** rounding down, that is the limit. ** Otherwise, check whether the limit can be converted to a float. If ** the float is too large, clip it to LUA_MAXINTEGER. If the float ** is too negative, the loop should not run, because any initial -** integer value is greater than such limit; so, it returns true to -** signal that. -** (For this latter case, no integer limit would be correct; even a -** limit of LUA_MININTEGER would run the loop once for an initial -** value equal to LUA_MININTEGER.) +** integer value is greater than such limit; so, the function returns +** true to signal that. (For this latter case, no integer limit would be +** correct; even a limit of LUA_MININTEGER would run the loop once for +** an initial value equal to LUA_MININTEGER.) */ static int forlimit (lua_State *L, lua_Integer init, const TValue *lim, lua_Integer *p, lua_Integer step) { @@ -183,6 +197,91 @@ static int forlimit (lua_State *L, lua_Integer init, const TValue *lim, } +/* +** Prepare a numerical for loop (opcode OP_FORPREP). +** Return true to skip the loop. Otherwise, +** after preparation, stack will be as follows: +** ra : internal index (safe copy of the control variable) +** ra + 1 : loop counter (integer loops) or limit (float loops) +** ra + 2 : step +** ra + 3 : control variable +*/ +static int forprep (lua_State *L, StkId ra) { + TValue *pinit = s2v(ra); + TValue *plimit = s2v(ra + 1); + TValue *pstep = s2v(ra + 2); + if (ttisinteger(pinit) && ttisinteger(pstep)) { /* integer loop? */ + lua_Integer init = ivalue(pinit); + lua_Integer step = ivalue(pstep); + lua_Integer limit; + if (step == 0) + luaG_runerror(L, "'for' step is zero"); + setivalue(s2v(ra + 3), init); /* control variable */ + if (forlimit(L, init, plimit, &limit, step)) + return 1; /* skip the loop */ + else { /* prepare loop counter */ + lua_Unsigned count; + if (step > 0) { /* ascending loop? */ + count = l_castS2U(limit) - l_castS2U(init); + if (step != 1) /* avoid division in the too common case */ + count /= l_castS2U(step); + } + else { /* step < 0; descending loop */ + count = l_castS2U(init) - l_castS2U(limit); + /* 'step+1' avoids negating 'mininteger' */ + count /= l_castS2U(-(step + 1)) + 1u; + } + /* store the counter in place of the limit (which won't be + needed anymore */ + setivalue(plimit, l_castU2S(count)); + } + } + else { /* try making all values floats */ + lua_Number init; lua_Number limit; lua_Number step; + if (unlikely(!tonumber(plimit, &limit))) + luaG_forerror(L, plimit, "limit"); + if (unlikely(!tonumber(pstep, &step))) + luaG_forerror(L, pstep, "step"); + if (unlikely(!tonumber(pinit, &init))) + luaG_forerror(L, pinit, "initial value"); + if (step == 0) + luaG_runerror(L, "'for' step is zero"); + if (luai_numlt(0, step) ? luai_numlt(limit, init) + : luai_numlt(init, limit)) + return 1; /* skip the loop */ + else { + /* make sure internal values are all floats */ + setfltvalue(plimit, limit); + setfltvalue(pstep, step); + setfltvalue(s2v(ra), init); /* internal index */ + setfltvalue(s2v(ra + 3), init); /* control variable */ + } + } + return 0; +} + + +/* +** Execute a step of a float numerical for loop, returning +** true iff the loop must continue. (The integer case is +** written online with opcode OP_FORLOOP, for performance.) +*/ +static int floatforloop (StkId ra) { + lua_Number step = fltvalue(s2v(ra + 2)); + lua_Number limit = fltvalue(s2v(ra + 1)); + lua_Number idx = fltvalue(s2v(ra)); /* internal index */ + idx = luai_numadd(L, idx, step); /* increment index */ + if (luai_numlt(0, step) ? luai_numle(idx, limit) + : luai_numle(limit, idx)) { + chgfltvalue(s2v(ra), idx); /* update internal index */ + setfltvalue(s2v(ra + 3), idx); /* and control variable */ + return 1; /* jump back */ + } + else + return 0; /* finish the loop */ +} + + /* ** Finish the table access 'val = t[key]'. ** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to @@ -1631,73 +1730,15 @@ void luaV_execute (lua_State *L, CallInfo *ci) { pc -= GETARG_Bx(i); /* jump back */ } } - else { /* floating loop */ - lua_Number step = fltvalue(s2v(ra + 2)); - lua_Number limit = fltvalue(s2v(ra + 1)); - lua_Number idx = fltvalue(s2v(ra)); - idx = luai_numadd(L, idx, step); /* increment index */ - if (luai_numlt(0, step) ? luai_numle(idx, limit) - : luai_numle(limit, idx)) { - chgfltvalue(s2v(ra), idx); /* update internal index */ - setfltvalue(s2v(ra + 3), idx); /* and control variable */ - pc -= GETARG_Bx(i); /* jump back */ - } - } + else if (floatforloop(ra)) /* float loop */ + pc -= GETARG_Bx(i); /* jump back */ updatetrap(ci); /* allows a signal to break the loop */ vmbreak; } vmcase(OP_FORPREP) { - TValue *pinit = s2v(ra); - TValue *plimit = s2v(ra + 1); - TValue *pstep = s2v(ra + 2); savestate(L, ci); /* in case of errors */ - if (ttisinteger(pinit) && ttisinteger(pstep)) { /* integer loop? */ - lua_Integer init = ivalue(pinit); - lua_Integer step = ivalue(pstep); - lua_Integer limit; - if (step == 0) - luaG_runerror(L, "'for' step is zero"); - setivalue(s2v(ra + 3), init); /* control variable */ - if (forlimit(L, init, plimit, &limit, step)) - pc += GETARG_Bx(i) + 1; /* skip the loop */ - else { /* prepare loop counter */ - lua_Unsigned count; - if (step > 0) { /* ascending loop? */ - count = l_castS2U(limit) - l_castS2U(init); - if (step != 1) /* avoid division in the too common case */ - count /= l_castS2U(step); - } - else { /* step < 0; descending loop */ - count = l_castS2U(init) - l_castS2U(limit); - /* 'step+1' avoids negating 'mininteger' */ - count /= l_castS2U(-(step + 1)) + 1u; - } - /* store the counter in place of the limit (which won't be - needed anymore */ - setivalue(plimit, l_castU2S(count)); - } - } - else { /* try making all values floats */ - lua_Number init; lua_Number limit; lua_Number step; - if (unlikely(!tonumber(plimit, &limit))) - luaG_forerror(L, plimit, "limit"); - if (unlikely(!tonumber(pstep, &step))) - luaG_forerror(L, pstep, "step"); - if (unlikely(!tonumber(pinit, &init))) - luaG_forerror(L, pinit, "initial value"); - if (step == 0) - luaG_runerror(L, "'for' step is zero"); - if (luai_numlt(0, step) ? luai_numlt(limit, init) - : luai_numlt(init, limit)) - pc += GETARG_Bx(i) + 1; /* skip the loop */ - else { - /* make sure internal values are all float */ - setfltvalue(plimit, limit); - setfltvalue(pstep, step); - setfltvalue(s2v(ra), init); /* internal index */ - setfltvalue(s2v(ra + 3), init); /* control variable */ - } - } + if (forprep(L, ra)) + pc += GETARG_Bx(i) + 1; /* skip the loop */ vmbreak; } vmcase(OP_TFORPREP) {