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cosmopolitan/third_party/duktape/duk_js_ops.c

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Initial import
2020-06-15 14:18:57 +00:00
/*
* ECMAScript specification algorithm and conversion helpers.
*
* These helpers encapsulate the primitive ECMAScript operation semantics,
* and are used by the bytecode executor and the API (among other places).
* Some primitives are only implemented as part of the API and have no
* "internal" helper. This is the case when an internal helper would not
* really be useful; e.g. the operation is rare, uses value stack heavily,
* etc.
*
* The operation arguments depend on what is required to implement
* the operation:
*
* - If an operation is simple and stateless, and has no side
* effects, it won't take an duk_hthread argument and its
* arguments may be duk_tval pointers (which are safe as long
* as no side effects take place).
*
* - If complex coercions are required (e.g. a "ToNumber" coercion)
* or errors may be thrown, the operation takes an duk_hthread
* argument. This also implies that the operation may have
* arbitrary side effects, invalidating any duk_tval pointers.
*
* - For operations with potential side effects, arguments can be
* taken in several ways:
*
* a) as duk_tval pointers, which makes sense if the "common case"
* can be resolved without side effects (e.g. coercion); the
* arguments are pushed to the valstack for coercion if
* necessary
*
* b) as duk_tval values
*
* c) implicitly on value stack top
*
* d) as indices to the value stack
*
* Future work:
*
* - Argument styles may not be the most sensible in every case now.
*
* - In-place coercions might be useful for several operations, if
* in-place coercion is OK for the bytecode executor and the API.
*/
#include "third_party/duktape/duk_internal.h"
/*
* ToPrimitive() (E5 Section 9.1)
*
* ==> implemented in the API.
*/
/*
* ToBoolean() (E5 Section 9.2)
*/
DUK_INTERNAL duk_bool_t duk_js_toboolean(duk_tval *tv) {
switch (DUK_TVAL_GET_TAG(tv)) {
case DUK_TAG_UNDEFINED:
case DUK_TAG_NULL:
return 0;
case DUK_TAG_BOOLEAN:
DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv) == 0 || DUK_TVAL_GET_BOOLEAN(tv) == 1);
return DUK_TVAL_GET_BOOLEAN(tv);
case DUK_TAG_STRING: {
/* Symbols ToBoolean() coerce to true, regardless of their
* description. This happens with no explicit check because
* of the symbol representation byte prefix.
*/
duk_hstring *h = DUK_TVAL_GET_STRING(tv);
DUK_ASSERT(h != NULL);
return (DUK_HSTRING_GET_BYTELEN(h) > 0 ? 1 : 0);
}
case DUK_TAG_OBJECT: {
return 1;
}
case DUK_TAG_BUFFER: {
/* Mimic Uint8Array semantics: objects coerce true, regardless
* of buffer length (zero or not) or context.
*/
return 1;
}
case DUK_TAG_POINTER: {
void *p = DUK_TVAL_GET_POINTER(tv);
return (p != NULL ? 1 : 0);
}
case DUK_TAG_LIGHTFUNC: {
return 1;
}
#if defined(DUK_USE_FASTINT)
case DUK_TAG_FASTINT:
if (DUK_TVAL_GET_FASTINT(tv) != 0) {
return 1;
} else {
return 0;
}
#endif
default: {
/* number */
duk_double_t d;
#if defined(DUK_USE_PREFER_SIZE)
int c;
#endif
DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
DUK_ASSERT(DUK_TVAL_IS_DOUBLE(tv));
d = DUK_TVAL_GET_DOUBLE(tv);
#if defined(DUK_USE_PREFER_SIZE)
c = DUK_FPCLASSIFY((double) d);
if (c == DUK_FP_ZERO || c == DUK_FP_NAN) {
return 0;
} else {
return 1;
}
#else
DUK_ASSERT(duk_double_is_nan_or_zero(d) == 0 || duk_double_is_nan_or_zero(d) == 1);
return duk_double_is_nan_or_zero(d) ^ 1;
#endif
}
}
DUK_UNREACHABLE();
DUK_WO_UNREACHABLE(return 0;);
}
/*
* ToNumber() (E5 Section 9.3)
*
* Value to convert must be on stack top, and is popped before exit.
*
* See: http://www.cs.indiana.edu/~burger/FP-Printing-PLDI96.pdf
* http://www.cs.indiana.edu/~burger/fp/index.html
*
* Notes on the conversion:
*
* - There are specific requirements on the accuracy of the conversion
* through a "Mathematical Value" (MV), so this conversion is not
* trivial.
*
* - Quick rejects (e.g. based on first char) are difficult because
* the grammar allows leading and trailing white space.
*
* - Quick reject based on string length is difficult even after
* accounting for white space; there may be arbitrarily many
* decimal digits.
*
* - Standard grammar allows decimal values ("123"), hex values
* ("0x123") and infinities
*
* - Unlike source code literals, ToNumber() coerces empty strings
* and strings with only whitespace to zero (not NaN). However,
* while '' coerces to 0, '+' and '-' coerce to NaN.
*/
/* E5 Section 9.3.1 */
DUK_LOCAL duk_double_t duk__tonumber_string_raw(duk_hthread *thr) {
duk_small_uint_t s2n_flags;
duk_double_t d;
DUK_ASSERT(duk_is_string(thr, -1));
/* Quite lenient, e.g. allow empty as zero, but don't allow trailing
* garbage.
*/
s2n_flags = DUK_S2N_FLAG_TRIM_WHITE |
DUK_S2N_FLAG_ALLOW_EXP |
DUK_S2N_FLAG_ALLOW_PLUS |
DUK_S2N_FLAG_ALLOW_MINUS |
DUK_S2N_FLAG_ALLOW_INF |
DUK_S2N_FLAG_ALLOW_FRAC |
DUK_S2N_FLAG_ALLOW_NAKED_FRAC |
DUK_S2N_FLAG_ALLOW_EMPTY_FRAC |
DUK_S2N_FLAG_ALLOW_EMPTY_AS_ZERO |
DUK_S2N_FLAG_ALLOW_LEADING_ZERO |
DUK_S2N_FLAG_ALLOW_AUTO_HEX_INT |
DUK_S2N_FLAG_ALLOW_AUTO_OCT_INT |
DUK_S2N_FLAG_ALLOW_AUTO_BIN_INT;
duk_numconv_parse(thr, 10 /*radix*/, s2n_flags);
#if defined(DUK_USE_PREFER_SIZE)
d = duk_get_number(thr, -1);
duk_pop_unsafe(thr);
#else
thr->valstack_top--;
DUK_ASSERT(DUK_TVAL_IS_NUMBER(thr->valstack_top));
DUK_ASSERT(DUK_TVAL_IS_DOUBLE(thr->valstack_top)); /* no fastint conversion in numconv now */
DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(thr->valstack_top));
d = DUK_TVAL_GET_DOUBLE(thr->valstack_top); /* assumes not a fastint */
DUK_TVAL_SET_UNDEFINED(thr->valstack_top);
#endif
return d;
}
DUK_INTERNAL duk_double_t duk_js_tonumber(duk_hthread *thr, duk_tval *tv) {
DUK_ASSERT(thr != NULL);
DUK_ASSERT(tv != NULL);
switch (DUK_TVAL_GET_TAG(tv)) {
case DUK_TAG_UNDEFINED: {
/* return a specific NaN (although not strictly necessary) */
duk_double_union du;
DUK_DBLUNION_SET_NAN(&du);
DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
return du.d;
}
case DUK_TAG_NULL: {
/* +0.0 */
return 0.0;
}
case DUK_TAG_BOOLEAN: {
if (DUK_TVAL_IS_BOOLEAN_TRUE(tv)) {
return 1.0;
}
return 0.0;
}
case DUK_TAG_STRING: {
/* For Symbols ToNumber() is always a TypeError. */
duk_hstring *h = DUK_TVAL_GET_STRING(tv);
if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(h))) {
DUK_ERROR_TYPE(thr, DUK_STR_CANNOT_NUMBER_COERCE_SYMBOL);
DUK_WO_NORETURN(return 0.0;);
}
duk_push_hstring(thr, h);
return duk__tonumber_string_raw(thr);
}
case DUK_TAG_BUFFER: /* plain buffer treated like object */
case DUK_TAG_OBJECT: {
duk_double_t d;
duk_push_tval(thr, tv);
duk_to_primitive(thr, -1, DUK_HINT_NUMBER); /* 'tv' becomes invalid */
/* recursive call for a primitive value (guaranteed not to cause second
* recursion).
*/
DUK_ASSERT(duk_get_tval(thr, -1) != NULL);
d = duk_js_tonumber(thr, duk_get_tval(thr, -1));
duk_pop_unsafe(thr);
return d;
}
case DUK_TAG_POINTER: {
/* Coerce like boolean */
void *p = DUK_TVAL_GET_POINTER(tv);
return (p != NULL ? 1.0 : 0.0);
}
case DUK_TAG_LIGHTFUNC: {
/* +(function(){}) -> NaN */
return DUK_DOUBLE_NAN;
}
#if defined(DUK_USE_FASTINT)
case DUK_TAG_FASTINT:
return (duk_double_t) DUK_TVAL_GET_FASTINT(tv);
#endif
default: {
/* number */
DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
DUK_ASSERT(DUK_TVAL_IS_DOUBLE(tv));
return DUK_TVAL_GET_DOUBLE(tv);
}
}
DUK_UNREACHABLE();
DUK_WO_UNREACHABLE(return 0.0;);
}
/*
* ToInteger() (E5 Section 9.4)
*/
/* exposed, used by e.g. duk_bi_date.c */
DUK_INTERNAL duk_double_t duk_js_tointeger_number(duk_double_t x) {
#if defined(DUK_USE_PREFER_SIZE)
duk_small_int_t c = (duk_small_int_t) DUK_FPCLASSIFY(x);
if (DUK_UNLIKELY(c == DUK_FP_NAN)) {
return 0.0;
} else if (DUK_UNLIKELY(c == DUK_FP_INFINITE)) {
return x;
} else {
/* Finite, including neg/pos zero. Neg zero sign must be
* preserved.
*/
return duk_double_trunc_towards_zero(x);
}
#else /* DUK_USE_PREFER_SIZE */
/* NaN and Infinity have the same exponent so it's a cheap
* initial check for the rare path.
*/
if (DUK_UNLIKELY(duk_double_is_nan_or_inf(x) != 0U)) {
if (duk_double_is_nan(x)) {
return 0.0;
} else {
return x;
}
} else {
return duk_double_trunc_towards_zero(x);
}
#endif /* DUK_USE_PREFER_SIZE */
}
DUK_INTERNAL duk_double_t duk_js_tointeger(duk_hthread *thr, duk_tval *tv) {
/* XXX: fastint */
duk_double_t d = duk_js_tonumber(thr, tv); /* invalidates tv */
return duk_js_tointeger_number(d);
}
/*
* ToInt32(), ToUint32(), ToUint16() (E5 Sections 9.5, 9.6, 9.7)
*/
/* combined algorithm matching E5 Sections 9.5 and 9.6 */
DUK_LOCAL duk_double_t duk__toint32_touint32_helper(duk_double_t x, duk_bool_t is_toint32) {
#if defined (DUK_USE_PREFER_SIZE)
duk_small_int_t c;
#endif
#if defined (DUK_USE_PREFER_SIZE)
c = (duk_small_int_t) DUK_FPCLASSIFY(x);
if (c == DUK_FP_NAN || c == DUK_FP_ZERO || c == DUK_FP_INFINITE) {
return 0.0;
}
#else
if (duk_double_is_nan_zero_inf(x)) {
return 0.0;
}
#endif
/* x = sign(x) * floor(abs(x)), i.e. truncate towards zero, keep sign */
x = duk_double_trunc_towards_zero(x);
/* NOTE: fmod(x) result sign is same as sign of x, which
* differs from what Javascript wants (see Section 9.6).
*/
x = DUK_FMOD(x, DUK_DOUBLE_2TO32); /* -> x in ]-2**32, 2**32[ */
if (x < 0.0) {
x += DUK_DOUBLE_2TO32;
}
DUK_ASSERT(x >= 0 && x < DUK_DOUBLE_2TO32); /* -> x in [0, 2**32[ */
if (is_toint32) {
if (x >= DUK_DOUBLE_2TO31) {
/* x in [2**31, 2**32[ */
x -= DUK_DOUBLE_2TO32; /* -> x in [-2**31,2**31[ */
}
}
return x;
}
DUK_INTERNAL duk_int32_t duk_js_toint32(duk_hthread *thr, duk_tval *tv) {
duk_double_t d;
#if defined(DUK_USE_FASTINT)
if (DUK_TVAL_IS_FASTINT(tv)) {
return DUK_TVAL_GET_FASTINT_I32(tv);
}
#endif
d = duk_js_tonumber(thr, tv); /* invalidates tv */
d = duk__toint32_touint32_helper(d, 1);
DUK_ASSERT(DUK_FPCLASSIFY(d) == DUK_FP_ZERO || DUK_FPCLASSIFY(d) == DUK_FP_NORMAL);
DUK_ASSERT(d >= -2147483648.0 && d <= 2147483647.0); /* [-0x80000000,0x7fffffff] */
DUK_ASSERT(duk_double_equals(d, (duk_double_t) ((duk_int32_t) d))); /* whole, won't clip */
return (duk_int32_t) d;
}
DUK_INTERNAL duk_uint32_t duk_js_touint32(duk_hthread *thr, duk_tval *tv) {
duk_double_t d;
#if defined(DUK_USE_FASTINT)
if (DUK_TVAL_IS_FASTINT(tv)) {
return DUK_TVAL_GET_FASTINT_U32(tv);
}
#endif
d = duk_js_tonumber(thr, tv); /* invalidates tv */
d = duk__toint32_touint32_helper(d, 0);
DUK_ASSERT(DUK_FPCLASSIFY(d) == DUK_FP_ZERO || DUK_FPCLASSIFY(d) == DUK_FP_NORMAL);
DUK_ASSERT(d >= 0.0 && d <= 4294967295.0); /* [0x00000000, 0xffffffff] */
DUK_ASSERT(duk_double_equals(d, (duk_double_t) ((duk_uint32_t) d))); /* whole, won't clip */
return (duk_uint32_t) d;
}
DUK_INTERNAL duk_uint16_t duk_js_touint16(duk_hthread *thr, duk_tval *tv) {
/* should be a safe way to compute this */
return (duk_uint16_t) (duk_js_touint32(thr, tv) & 0x0000ffffU);
}
/*
* ToString() (E5 Section 9.8)
* ToObject() (E5 Section 9.9)
* CheckObjectCoercible() (E5 Section 9.10)
* IsCallable() (E5 Section 9.11)
*
* ==> implemented in the API.
*/
/*
* Loose equality, strict equality, and SameValue (E5 Sections 11.9.1, 11.9.4,
* 9.12). These have much in common so they can share some helpers.
*
* Future work notes:
*
* - Current implementation (and spec definition) has recursion; this should
* be fixed if possible.
*
* - String-to-number coercion should be possible without going through the
* value stack (and be more compact) if a shared helper is invoked.
*/
/* Note that this is the same operation for strict and loose equality:
* - E5 Section 11.9.3, step 1.c (loose)
* - E5 Section 11.9.6, step 4 (strict)
*/
DUK_LOCAL duk_bool_t duk__js_equals_number(duk_double_t x, duk_double_t y) {
#if defined(DUK_USE_PARANOID_MATH)
/* Straightforward algorithm, makes fewer compiler assumptions. */
duk_small_int_t cx = (duk_small_int_t) DUK_FPCLASSIFY(x);
duk_small_int_t cy = (duk_small_int_t) DUK_FPCLASSIFY(y);
if (cx == DUK_FP_NAN || cy == DUK_FP_NAN) {
return 0;
}
if (cx == DUK_FP_ZERO && cy == DUK_FP_ZERO) {
return 1;
}
if (x == y) {
return 1;
}
return 0;
#else /* DUK_USE_PARANOID_MATH */
/* Better equivalent algorithm. If the compiler is compliant, C and
* ECMAScript semantics are identical for this particular comparison.
* In particular, NaNs must never compare equal and zeroes must compare
* equal regardless of sign. Could also use a macro, but this inlines
* already nicely (no difference on gcc, for instance).
*/
if (duk_double_equals(x, y)) {
/* IEEE requires that NaNs compare false */
DUK_ASSERT(DUK_FPCLASSIFY(x) != DUK_FP_NAN);
DUK_ASSERT(DUK_FPCLASSIFY(y) != DUK_FP_NAN);
return 1;
} else {
/* IEEE requires that zeros compare the same regardless
* of their signed, so if both x and y are zeroes, they
* are caught above.
*/
DUK_ASSERT(!(DUK_FPCLASSIFY(x) == DUK_FP_ZERO && DUK_FPCLASSIFY(y) == DUK_FP_ZERO));
return 0;
}
#endif /* DUK_USE_PARANOID_MATH */
}
DUK_LOCAL duk_bool_t duk__js_samevalue_number(duk_double_t x, duk_double_t y) {
#if defined(DUK_USE_PARANOID_MATH)
duk_small_int_t cx = (duk_small_int_t) DUK_FPCLASSIFY(x);
duk_small_int_t cy = (duk_small_int_t) DUK_FPCLASSIFY(y);
if (cx == DUK_FP_NAN && cy == DUK_FP_NAN) {
/* SameValue(NaN, NaN) = true, regardless of NaN sign or extra bits */
return 1;
}
if (cx == DUK_FP_ZERO && cy == DUK_FP_ZERO) {
/* Note: cannot assume that a non-zero return value of signbit() would
* always be the same -- hence cannot (portably) use something like:
*
* signbit(x) == signbit(y)
*/
duk_small_int_t sx = DUK_SIGNBIT(x) ? 1 : 0;
duk_small_int_t sy = DUK_SIGNBIT(y) ? 1 : 0;
return (sx == sy);
}
/* normal comparison; known:
* - both x and y are not NaNs (but one of them can be)
* - both x and y are not zero (but one of them can be)
* - x and y may be denormal or infinite
*/
return (x == y);
#else /* DUK_USE_PARANOID_MATH */
duk_small_int_t cx = (duk_small_int_t) DUK_FPCLASSIFY(x);
duk_small_int_t cy = (duk_small_int_t) DUK_FPCLASSIFY(y);
if (duk_double_equals(x, y)) {
/* IEEE requires that NaNs compare false */
DUK_ASSERT(DUK_FPCLASSIFY(x) != DUK_FP_NAN);
DUK_ASSERT(DUK_FPCLASSIFY(y) != DUK_FP_NAN);
/* Using classification has smaller footprint than direct comparison. */
if (DUK_UNLIKELY(cx == DUK_FP_ZERO && cy == DUK_FP_ZERO)) {
/* Note: cannot assume that a non-zero return value of signbit() would
* always be the same -- hence cannot (portably) use something like:
*
* signbit(x) == signbit(y)
*/
return duk_double_same_sign(x, y);
}
return 1;
} else {
/* IEEE requires that zeros compare the same regardless
* of their sign, so if both x and y are zeroes, they
* are caught above.
*/
DUK_ASSERT(!(DUK_FPCLASSIFY(x) == DUK_FP_ZERO && DUK_FPCLASSIFY(y) == DUK_FP_ZERO));
/* Difference to non-strict/strict comparison is that NaNs compare
* equal and signed zero signs matter.
*/
if (DUK_UNLIKELY(cx == DUK_FP_NAN && cy == DUK_FP_NAN)) {
/* SameValue(NaN, NaN) = true, regardless of NaN sign or extra bits */
return 1;
}
return 0;
}
#endif /* DUK_USE_PARANOID_MATH */
}
DUK_INTERNAL duk_bool_t duk_js_equals_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_t flags) {
duk_uint_t type_mask_x;
duk_uint_t type_mask_y;
/* If flags != 0 (strict or SameValue), thr can be NULL. For loose
* equals comparison it must be != NULL.
*/
DUK_ASSERT(flags != 0 || thr != NULL);
/*
* Same type?
*
* Note: since number values have no explicit tag in the 8-byte
* representation, need the awkward if + switch.
*/
#if defined(DUK_USE_FASTINT)
if (DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y)) {
if (DUK_TVAL_GET_FASTINT(tv_x) == DUK_TVAL_GET_FASTINT(tv_y)) {
return 1;
} else {
return 0;
}
}
else
#endif
if (DUK_TVAL_IS_NUMBER(tv_x) && DUK_TVAL_IS_NUMBER(tv_y)) {
duk_double_t d1, d2;
/* Catches both doubles and cases where only one argument is
* a fastint so can't assume a double.
*/
d1 = DUK_TVAL_GET_NUMBER(tv_x);
d2 = DUK_TVAL_GET_NUMBER(tv_y);
if (DUK_UNLIKELY((flags & DUK_EQUALS_FLAG_SAMEVALUE) != 0)) {
/* SameValue */
return duk__js_samevalue_number(d1, d2);
} else {
/* equals and strict equals */
return duk__js_equals_number(d1, d2);
}
} else if (DUK_TVAL_GET_TAG(tv_x) == DUK_TVAL_GET_TAG(tv_y)) {
switch (DUK_TVAL_GET_TAG(tv_x)) {
case DUK_TAG_UNDEFINED:
case DUK_TAG_NULL: {
return 1;
}
case DUK_TAG_BOOLEAN: {
return DUK_TVAL_GET_BOOLEAN(tv_x) == DUK_TVAL_GET_BOOLEAN(tv_y);
}
case DUK_TAG_POINTER: {
return DUK_TVAL_GET_POINTER(tv_x) == DUK_TVAL_GET_POINTER(tv_y);
}
case DUK_TAG_STRING:
case DUK_TAG_OBJECT: {
/* Heap pointer comparison suffices for strings and objects.
* Symbols compare equal if they have the same internal
* representation; again heap pointer comparison suffices.
*/
return DUK_TVAL_GET_HEAPHDR(tv_x) == DUK_TVAL_GET_HEAPHDR(tv_y);
}
case DUK_TAG_BUFFER: {
/* In Duktape 2.x plain buffers mimic Uint8Array objects
* so always compare by heap pointer. In Duktape 1.x
* strict comparison would compare heap pointers and
* non-strict would compare contents.
*/
return DUK_TVAL_GET_HEAPHDR(tv_x) == DUK_TVAL_GET_HEAPHDR(tv_y);
}
case DUK_TAG_LIGHTFUNC: {
/* At least 'magic' has a significant impact on function
* identity.
*/
duk_small_uint_t lf_flags_x;
duk_small_uint_t lf_flags_y;
duk_c_function func_x;
duk_c_function func_y;
DUK_TVAL_GET_LIGHTFUNC(tv_x, func_x, lf_flags_x);
DUK_TVAL_GET_LIGHTFUNC(tv_y, func_y, lf_flags_y);
return ((func_x == func_y) && (lf_flags_x == lf_flags_y)) ? 1 : 0;
}
#if defined(DUK_USE_FASTINT)
case DUK_TAG_FASTINT:
#endif
default: {
DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_x));
DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_y));
DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_x));
DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_y));
DUK_UNREACHABLE();
DUK_WO_UNREACHABLE(return 0;);
}
}
}
if ((flags & (DUK_EQUALS_FLAG_STRICT | DUK_EQUALS_FLAG_SAMEVALUE)) != 0) {
return 0;
}
DUK_ASSERT(flags == 0); /* non-strict equality from here on */
/*
* Types are different; various cases for non-strict comparison
*
* Since comparison is symmetric, we use a "swap trick" to reduce
* code size.
*/
type_mask_x = duk_get_type_mask_tval(tv_x);
type_mask_y = duk_get_type_mask_tval(tv_y);
/* Undefined/null are considered equal (e.g. "null == undefined" -> true). */
if ((type_mask_x & (DUK_TYPE_MASK_UNDEFINED | DUK_TYPE_MASK_NULL)) &&
(type_mask_y & (DUK_TYPE_MASK_NULL | DUK_TYPE_MASK_UNDEFINED))) {
return 1;
}
/* Number/string -> coerce string to number (e.g. "'1.5' == 1.5" -> true). */
if ((type_mask_x & DUK_TYPE_MASK_NUMBER) && (type_mask_y & DUK_TYPE_MASK_STRING)) {
if (!DUK_TVAL_STRING_IS_SYMBOL(tv_y)) {
duk_double_t d1, d2;
d1 = DUK_TVAL_GET_NUMBER(tv_x);
d2 = duk_to_number_tval(thr, tv_y);
return duk__js_equals_number(d1, d2);
}
}
if ((type_mask_x & DUK_TYPE_MASK_STRING) && (type_mask_y & DUK_TYPE_MASK_NUMBER)) {
if (!DUK_TVAL_STRING_IS_SYMBOL(tv_x)) {
duk_double_t d1, d2;
d1 = DUK_TVAL_GET_NUMBER(tv_y);
d2 = duk_to_number_tval(thr, tv_x);
return duk__js_equals_number(d1, d2);
}
}
/* Boolean/any -> coerce boolean to number and try again. If boolean is
* compared to a pointer, the final comparison after coercion now always
* yields false (as pointer vs. number compares to false), but this is
* not special cased.
*
* ToNumber(bool) is +1.0 or 0.0. Tagged boolean value is always 0 or 1.
*/
if (type_mask_x & DUK_TYPE_MASK_BOOLEAN) {
DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv_x) == 0 || DUK_TVAL_GET_BOOLEAN(tv_x) == 1);
duk_push_uint(thr, DUK_TVAL_GET_BOOLEAN(tv_x));
duk_push_tval(thr, tv_y);
goto recursive_call;
}
if (type_mask_y & DUK_TYPE_MASK_BOOLEAN) {
DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv_y) == 0 || DUK_TVAL_GET_BOOLEAN(tv_y) == 1);
duk_push_tval(thr, tv_x);
duk_push_uint(thr, DUK_TVAL_GET_BOOLEAN(tv_y));
goto recursive_call;
}
/* String-number-symbol/object -> coerce object to primitive (apparently without hint), then try again. */
if ((type_mask_x & (DUK_TYPE_MASK_STRING | DUK_TYPE_MASK_NUMBER)) &&
(type_mask_y & DUK_TYPE_MASK_OBJECT)) {
/* No symbol check needed because symbols and strings are accepted. */
duk_push_tval(thr, tv_x);
duk_push_tval(thr, tv_y);
duk_to_primitive(thr, -1, DUK_HINT_NONE); /* apparently no hint? */
goto recursive_call;
}
if ((type_mask_x & DUK_TYPE_MASK_OBJECT) &&
(type_mask_y & (DUK_TYPE_MASK_STRING | DUK_TYPE_MASK_NUMBER))) {
/* No symbol check needed because symbols and strings are accepted. */
duk_push_tval(thr, tv_x);
duk_push_tval(thr, tv_y);
duk_to_primitive(thr, -2, DUK_HINT_NONE); /* apparently no hint? */
goto recursive_call;
}
/* Nothing worked -> not equal. */
return 0;
recursive_call:
/* Shared code path to call the helper again with arguments on stack top. */
{
duk_bool_t rc;
rc = duk_js_equals_helper(thr,
DUK_GET_TVAL_NEGIDX(thr, -2),
DUK_GET_TVAL_NEGIDX(thr, -1),
0 /*flags:nonstrict*/);
duk_pop_2_unsafe(thr);
return rc;
}
}
/*
* Comparisons (x >= y, x > y, x <= y, x < y)
*
* E5 Section 11.8.5: implement 'x < y' and then use negate and eval_left_first
* flags to get the rest.
*/
/* XXX: this should probably just operate on the stack top, because it
* needs to push stuff on the stack anyway...
*/
DUK_INTERNAL duk_small_int_t duk_js_data_compare(const duk_uint8_t *buf1, const duk_uint8_t *buf2, duk_size_t len1, duk_size_t len2) {
duk_size_t prefix_len;
duk_small_int_t rc;
prefix_len = (len1 <= len2 ? len1 : len2);
/* duk_memcmp() is guaranteed to return zero (equal) for zero length
* inputs.
*/
rc = duk_memcmp_unsafe((const void *) buf1,
(const void *) buf2,
(size_t) prefix_len);
if (rc < 0) {
return -1;
} else if (rc > 0) {
return 1;
}
/* prefix matches, lengths matter now */
if (len1 < len2) {
/* e.g. "x" < "xx" */
return -1;
} else if (len1 > len2) {
return 1;
}
return 0;
}
DUK_INTERNAL duk_small_int_t duk_js_string_compare(duk_hstring *h1, duk_hstring *h2) {
/*
* String comparison (E5 Section 11.8.5, step 4), which
* needs to compare codepoint by codepoint.
*
* However, UTF-8 allows us to use strcmp directly: the shared
* prefix will be encoded identically (UTF-8 has unique encoding)
* and the first differing character can be compared with a simple
* unsigned byte comparison (which strcmp does).
*
* This will not work properly for non-xutf-8 strings, but this
* is not an issue for compliance.
*/
DUK_ASSERT(h1 != NULL);
DUK_ASSERT(h2 != NULL);
return duk_js_data_compare((const duk_uint8_t *) DUK_HSTRING_GET_DATA(h1),
(const duk_uint8_t *) DUK_HSTRING_GET_DATA(h2),
(duk_size_t) DUK_HSTRING_GET_BYTELEN(h1),
(duk_size_t) DUK_HSTRING_GET_BYTELEN(h2));
}
#if 0 /* unused */
DUK_INTERNAL duk_small_int_t duk_js_buffer_compare(duk_heap *heap, duk_hbuffer *h1, duk_hbuffer *h2) {
/* Similar to String comparison. */
DUK_ASSERT(h1 != NULL);
DUK_ASSERT(h2 != NULL);
DUK_UNREF(heap);
return duk_js_data_compare((const duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(heap, h1),
(const duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(heap, h2),
(duk_size_t) DUK_HBUFFER_GET_SIZE(h1),
(duk_size_t) DUK_HBUFFER_GET_SIZE(h2));
}
#endif
#if defined(DUK_USE_FASTINT)
DUK_LOCAL duk_bool_t duk__compare_fastint(duk_bool_t retval, duk_int64_t v1, duk_int64_t v2) {
DUK_ASSERT(retval == 0 || retval == 1);
if (v1 < v2) {
return retval ^ 1;
} else {
return retval;
}
}
#endif
#if defined(DUK_USE_PARANOID_MATH)
DUK_LOCAL duk_bool_t duk__compare_number(duk_bool_t retval, duk_double_t d1, duk_double_t d2) {
duk_small_int_t c1, s1, c2, s2;
DUK_ASSERT(retval == 0 || retval == 1);
c1 = (duk_small_int_t) DUK_FPCLASSIFY(d1);
s1 = (duk_small_int_t) DUK_SIGNBIT(d1);
c2 = (duk_small_int_t) DUK_FPCLASSIFY(d2);
s2 = (duk_small_int_t) DUK_SIGNBIT(d2);
if (c1 == DUK_FP_NAN || c2 == DUK_FP_NAN) {
return 0; /* Always false, regardless of negation. */
}
if (c1 == DUK_FP_ZERO && c2 == DUK_FP_ZERO) {
/* For all combinations: +0 < +0, +0 < -0, -0 < +0, -0 < -0,
* steps e, f, and g.
*/
return retval; /* false */
}
if (d1 == d2) {
return retval; /* false */
}
if (c1 == DUK_FP_INFINITE && s1 == 0) {
/* x == +Infinity */
return retval; /* false */
}
if (c2 == DUK_FP_INFINITE && s2 == 0) {
/* y == +Infinity */
return retval ^ 1; /* true */
}
if (c2 == DUK_FP_INFINITE && s2 != 0) {
/* y == -Infinity */
return retval; /* false */
}
if (c1 == DUK_FP_INFINITE && s1 != 0) {
/* x == -Infinity */
return retval ^ 1; /* true */
}
if (d1 < d2) {
return retval ^ 1; /* true */
}
return retval; /* false */
}
#else /* DUK_USE_PARANOID_MATH */
DUK_LOCAL duk_bool_t duk__compare_number(duk_bool_t retval, duk_double_t d1, duk_double_t d2) {
/* This comparison tree relies doesn't match the exact steps in
* E5 Section 11.8.5 but should produce the same results. The
* steps rely on exact IEEE semantics for NaNs, etc.
*/
DUK_ASSERT(retval == 0 || retval == 1);
if (d1 < d2) {
/* In no case should both (d1 < d2) and (d2 < d1) be true.
* It's possible that neither is true though, and that's
* handled below.
*/
DUK_ASSERT(!(d2 < d1));
/* - d1 < d2, both d1/d2 are normals (not Infinity, not NaN)
* - d2 is +Infinity, d1 != +Infinity and NaN
* - d1 is -Infinity, d2 != -Infinity and NaN
*/
return retval ^ 1;
} else {
if (d2 < d1) {
/* - !(d1 < d2), both d1/d2 are normals (not Infinity, not NaN)
* - d1 is +Infinity, d2 != +Infinity and NaN
* - d2 is -Infinity, d1 != -Infinity and NaN
*/
return retval;
} else {
/* - d1 and/or d2 is NaN
* - d1 and d2 are both +/- 0
* - d1 == d2 (including infinities)
*/
if (duk_double_is_nan(d1) || duk_double_is_nan(d2)) {
/* Note: undefined from Section 11.8.5 always
* results in false return (see e.g. Section
* 11.8.3) - hence special treatment here.
*/
return 0; /* zero regardless of negation */
} else {
return retval;
}
}
}
}
#endif /* DUK_USE_PARANOID_MATH */
DUK_INTERNAL duk_bool_t duk_js_compare_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_uint_t flags) {
duk_double_t d1, d2;
duk_small_int_t rc;
duk_bool_t retval;
DUK_ASSERT(DUK_COMPARE_FLAG_NEGATE == 1); /* Rely on this flag being lowest. */
retval = flags & DUK_COMPARE_FLAG_NEGATE;
DUK_ASSERT(retval == 0 || retval == 1);
/* Fast path for fastints */
#if defined(DUK_USE_FASTINT)
if (DUK_LIKELY(DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y))) {
return duk__compare_fastint(retval,
DUK_TVAL_GET_FASTINT(tv_x),
DUK_TVAL_GET_FASTINT(tv_y));
}
#endif /* DUK_USE_FASTINT */
/* Fast path for numbers (one of which may be a fastint) */
#if !defined(DUK_USE_PREFER_SIZE)
if (DUK_LIKELY(DUK_TVAL_IS_NUMBER(tv_x) && DUK_TVAL_IS_NUMBER(tv_y))) {
return duk__compare_number(retval,
DUK_TVAL_GET_NUMBER(tv_x),
DUK_TVAL_GET_NUMBER(tv_y));
}
#endif
/* Slow path */
duk_push_tval(thr, tv_x);
duk_push_tval(thr, tv_y);
if (flags & DUK_COMPARE_FLAG_EVAL_LEFT_FIRST) {
duk_to_primitive(thr, -2, DUK_HINT_NUMBER);
duk_to_primitive(thr, -1, DUK_HINT_NUMBER);
} else {
duk_to_primitive(thr, -1, DUK_HINT_NUMBER);
duk_to_primitive(thr, -2, DUK_HINT_NUMBER);
}
/* Note: reuse variables */
tv_x = DUK_GET_TVAL_NEGIDX(thr, -2);
tv_y = DUK_GET_TVAL_NEGIDX(thr, -1);
if (DUK_TVAL_IS_STRING(tv_x) && DUK_TVAL_IS_STRING(tv_y)) {
duk_hstring *h1 = DUK_TVAL_GET_STRING(tv_x);
duk_hstring *h2 = DUK_TVAL_GET_STRING(tv_y);
DUK_ASSERT(h1 != NULL);
DUK_ASSERT(h2 != NULL);
if (DUK_LIKELY(!DUK_HSTRING_HAS_SYMBOL(h1) && !DUK_HSTRING_HAS_SYMBOL(h2))) {
rc = duk_js_string_compare(h1, h2);
duk_pop_2_unsafe(thr);
if (rc < 0) {
return retval ^ 1;
} else {
return retval;
}
}
/* One or both are Symbols: fall through to handle in the
* generic path. Concretely, ToNumber() will fail.
*/
}
/* Ordering should not matter (E5 Section 11.8.5, step 3.a). */
#if 0
if (flags & DUK_COMPARE_FLAG_EVAL_LEFT_FIRST) {
d1 = duk_to_number_m2(thr);
d2 = duk_to_number_m1(thr);
} else {
d2 = duk_to_number_m1(thr);
d1 = duk_to_number_m2(thr);
}
#endif
d1 = duk_to_number_m2(thr);
d2 = duk_to_number_m1(thr);
/* We want to duk_pop_2_unsafe(thr); because the values are numbers
* no decref check is needed.
*/
#if defined(DUK_USE_PREFER_SIZE)
duk_pop_2_nodecref_unsafe(thr);
#else
DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(duk_get_tval(thr, -2)));
DUK_ASSERT(!DUK_TVAL_NEEDS_REFCOUNT_UPDATE(duk_get_tval(thr, -1)));
DUK_ASSERT(duk_get_top(thr) >= 2);
thr->valstack_top -= 2;
tv_x = thr->valstack_top;
tv_y = tv_x + 1;
DUK_TVAL_SET_UNDEFINED(tv_x); /* Value stack policy */
DUK_TVAL_SET_UNDEFINED(tv_y);
#endif
return duk__compare_number(retval, d1, d2);
}
/*
* instanceof
*/
/*
* ES2015 Section 7.3.19 describes the OrdinaryHasInstance() algorithm
* which covers both bound and non-bound functions; in effect the algorithm
* includes E5 Sections 11.8.6, 15.3.5.3, and 15.3.4.5.3.
*
* ES2015 Section 12.9.4 describes the instanceof operator which first
* checks @@hasInstance well-known symbol and falls back to
* OrdinaryHasInstance().
*
* Limited Proxy support: don't support 'getPrototypeOf' trap but
* continue lookup in Proxy target if the value is a Proxy.
*/
DUK_LOCAL duk_bool_t duk__js_instanceof_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_bool_t skip_sym_check) {
duk_hobject *func;
duk_hobject *val;
duk_hobject *proto;
duk_tval *tv;
duk_bool_t skip_first;
duk_uint_t sanity;
/*
* Get the values onto the stack first. It would be possible to cover
* some normal cases without resorting to the value stack.
*
* The right hand side could be a light function (as they generally
* behave like objects). Light functions never have a 'prototype'
* property so E5.1 Section 15.3.5.3 step 3 always throws a TypeError.
* Using duk_require_hobject() is thus correct (except for error msg).
*/
duk_push_tval(thr, tv_x);
duk_push_tval(thr, tv_y);
func = duk_require_hobject(thr, -1);
DUK_ASSERT(func != NULL);
#if defined(DUK_USE_SYMBOL_BUILTIN)
/*
* @@hasInstance check, ES2015 Section 12.9.4, Steps 2-4.
*/
if (!skip_sym_check) {
if (duk_get_method_stridx(thr, -1, DUK_STRIDX_WELLKNOWN_SYMBOL_HAS_INSTANCE)) {
/* [ ... lhs rhs func ] */
duk_insert(thr, -3); /* -> [ ... func lhs rhs ] */
duk_swap_top(thr, -2); /* -> [ ... func rhs(this) lhs ] */
duk_call_method(thr, 1);
return duk_to_boolean_top_pop(thr);
}
}
#else
DUK_UNREF(skip_sym_check);
#endif
/*
* For bound objects, [[HasInstance]] just calls the target function
* [[HasInstance]]. If that is again a bound object, repeat until
* we find a non-bound Function object.
*
* The bound function chain is now "collapsed" so there can be only
* one bound function in the chain.
*/
if (!DUK_HOBJECT_IS_CALLABLE(func)) {
/*
* Note: of native ECMAScript objects, only Function instances
* have a [[HasInstance]] internal property. Custom objects might
* also have it, but not in current implementation.
*
* XXX: add a separate flag, DUK_HOBJECT_FLAG_ALLOW_INSTANCEOF?
*/
goto error_invalid_rval;
}
if (DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
duk_push_tval(thr, &((duk_hboundfunc *) (void *) func)->target);
duk_replace(thr, -2);
func = duk_require_hobject(thr, -1); /* lightfunc throws */
/* Rely on Function.prototype.bind() never creating bound
* functions whose target is not proper.
*/
DUK_ASSERT(func != NULL);
DUK_ASSERT(DUK_HOBJECT_IS_CALLABLE(func));
}
/*
* 'func' is now a non-bound object which supports [[HasInstance]]
* (which here just means DUK_HOBJECT_FLAG_CALLABLE). Move on
* to execute E5 Section 15.3.5.3.
*/
DUK_ASSERT(func != NULL);
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(DUK_HOBJECT_IS_CALLABLE(func));
/* [ ... lval rval(func) ] */
/* For lightfuncs, buffers, and pointers start the comparison directly
* from the virtual prototype object.
*/
skip_first = 0;
tv = DUK_GET_TVAL_NEGIDX(thr, -2);
switch (DUK_TVAL_GET_TAG(tv)) {
case DUK_TAG_LIGHTFUNC:
val = thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE];
DUK_ASSERT(val != NULL);
break;
case DUK_TAG_BUFFER:
val = thr->builtins[DUK_BIDX_UINT8ARRAY_PROTOTYPE];
DUK_ASSERT(val != NULL);
break;
case DUK_TAG_POINTER:
val = thr->builtins[DUK_BIDX_POINTER_PROTOTYPE];
DUK_ASSERT(val != NULL);
break;
case DUK_TAG_OBJECT:
skip_first = 1; /* Ignore object itself on first round. */
val = DUK_TVAL_GET_OBJECT(tv);
DUK_ASSERT(val != NULL);
break;
default:
goto pop2_and_false;
}
DUK_ASSERT(val != NULL); /* Loop doesn't actually rely on this. */
/* Look up .prototype of rval. Leave it on the value stack in case it
* has been virtualized (e.g. getter, Proxy trap).
*/
duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_PROTOTYPE); /* -> [ ... lval rval rval.prototype ] */
#if defined(DUK_USE_VERBOSE_ERRORS)
proto = duk_get_hobject(thr, -1);
if (proto == NULL) {
goto error_invalid_rval_noproto;
}
#else
proto = duk_require_hobject(thr, -1);
#endif
sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
do {
/*
* Note: prototype chain is followed BEFORE first comparison. This
* means that the instanceof lval is never itself compared to the
* rval.prototype property. This is apparently intentional, see E5
* Section 15.3.5.3, step 4.a.
*
* Also note:
*
* js> (function() {}) instanceof Function
* true
* js> Function instanceof Function
* true
*
* For the latter, h_proto will be Function.prototype, which is the
* built-in Function prototype. Because Function.[[Prototype]] is
* also the built-in Function prototype, the result is true.
*/
if (!val) {
goto pop3_and_false;
}
DUK_ASSERT(val != NULL);
#if defined(DUK_USE_ES6_PROXY)
val = duk_hobject_resolve_proxy_target(val);
#endif
if (skip_first) {
skip_first = 0;
} else if (val == proto) {
goto pop3_and_true;
}
DUK_ASSERT(val != NULL);
val = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, val);
} while (--sanity > 0);
DUK_ASSERT(sanity == 0);
DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
DUK_WO_NORETURN(return 0;);
pop2_and_false:
duk_pop_2_unsafe(thr);
return 0;
pop3_and_false:
duk_pop_3_unsafe(thr);
return 0;
pop3_and_true:
duk_pop_3_unsafe(thr);
return 1;
error_invalid_rval:
DUK_ERROR_TYPE(thr, DUK_STR_INVALID_INSTANCEOF_RVAL);
DUK_WO_NORETURN(return 0;);
#if defined(DUK_USE_VERBOSE_ERRORS)
error_invalid_rval_noproto:
DUK_ERROR_TYPE(thr, DUK_STR_INVALID_INSTANCEOF_RVAL_NOPROTO);
DUK_WO_NORETURN(return 0;);
#endif
}
#if defined(DUK_USE_SYMBOL_BUILTIN)
DUK_INTERNAL duk_bool_t duk_js_instanceof_ordinary(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y) {
return duk__js_instanceof_helper(thr, tv_x, tv_y, 1 /*skip_sym_check*/);
}
#endif
DUK_INTERNAL duk_bool_t duk_js_instanceof(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y) {
return duk__js_instanceof_helper(thr, tv_x, tv_y, 0 /*skip_sym_check*/);
}
/*
* in
*/
/*
* E5 Sections 11.8.7, 8.12.6.
*
* Basically just a property existence check using [[HasProperty]].
*/
DUK_INTERNAL duk_bool_t duk_js_in(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y) {
duk_bool_t retval;
/*
* Get the values onto the stack first. It would be possible to cover
* some normal cases without resorting to the value stack (e.g. if
* lval is already a string).
*/
/* XXX: The ES5/5.1/6 specifications require that the key in 'key in obj'
* must be string coerced before the internal HasProperty() algorithm is
* invoked. A fast path skipping coercion could be safely implemented for
* numbers (as number-to-string coercion has no side effects). For ES2015
* proxy behavior, the trap 'key' argument must be in a string coerced
* form (which is a shame).
*/
/* TypeError if rval is not an object or object like (e.g. lightfunc
* or plain buffer).
*/
duk_push_tval(thr, tv_x);
duk_push_tval(thr, tv_y);
duk_require_type_mask(thr, -1, DUK_TYPE_MASK_OBJECT | DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
(void) duk_to_property_key_hstring(thr, -2);
retval = duk_hobject_hasprop(thr,
DUK_GET_TVAL_NEGIDX(thr, -1),
DUK_GET_TVAL_NEGIDX(thr, -2));
duk_pop_2_unsafe(thr);
return retval;
}
/*
* typeof
*
* E5 Section 11.4.3.
*
* Very straightforward. The only question is what to return for our
* non-standard tag / object types.
*
* There is an unfortunate string constant define naming problem with
* typeof return values for e.g. "Object" and "object"; careful with
* the built-in string defines. The LC_XXX defines are used for the
* lowercase variants now.
*/
DUK_INTERNAL duk_small_uint_t duk_js_typeof_stridx(duk_tval *tv_x) {
duk_small_uint_t stridx = 0;
switch (DUK_TVAL_GET_TAG(tv_x)) {
case DUK_TAG_UNDEFINED: {
stridx = DUK_STRIDX_LC_UNDEFINED;
break;
}
case DUK_TAG_NULL: {
/* Note: not a typo, "object" is returned for a null value. */
stridx = DUK_STRIDX_LC_OBJECT;
break;
}
case DUK_TAG_BOOLEAN: {
stridx = DUK_STRIDX_LC_BOOLEAN;
break;
}
case DUK_TAG_POINTER: {
/* Implementation specific. */
stridx = DUK_STRIDX_LC_POINTER;
break;
}
case DUK_TAG_STRING: {
duk_hstring *str;
/* All internal keys are identified as Symbols. */
str = DUK_TVAL_GET_STRING(tv_x);
DUK_ASSERT(str != NULL);
if (DUK_UNLIKELY(DUK_HSTRING_HAS_SYMBOL(str))) {
stridx = DUK_STRIDX_LC_SYMBOL;
} else {
stridx = DUK_STRIDX_LC_STRING;
}
break;
}
case DUK_TAG_OBJECT: {
duk_hobject *obj = DUK_TVAL_GET_OBJECT(tv_x);
DUK_ASSERT(obj != NULL);
if (DUK_HOBJECT_IS_CALLABLE(obj)) {
stridx = DUK_STRIDX_LC_FUNCTION;
} else {
stridx = DUK_STRIDX_LC_OBJECT;
}
break;
}
case DUK_TAG_BUFFER: {
/* Implementation specific. In Duktape 1.x this would be
* 'buffer', in Duktape 2.x changed to 'object' because plain
* buffers now mimic Uint8Array objects.
*/
stridx = DUK_STRIDX_LC_OBJECT;
break;
}
case DUK_TAG_LIGHTFUNC: {
stridx = DUK_STRIDX_LC_FUNCTION;
break;
}
#if defined(DUK_USE_FASTINT)
case DUK_TAG_FASTINT:
#endif
default: {
/* number */
DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_x));
DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_x));
stridx = DUK_STRIDX_LC_NUMBER;
break;
}
}
DUK_ASSERT_STRIDX_VALID(stridx);
return stridx;
}
/*
* IsArray()
*/
DUK_INTERNAL duk_bool_t duk_js_isarray_hobject(duk_hobject *h) {
DUK_ASSERT(h != NULL);
h = duk_hobject_resolve_proxy_target(h);
return (DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_ARRAY ? 1 : 0);
}
DUK_INTERNAL duk_bool_t duk_js_isarray(duk_tval *tv) {
DUK_ASSERT(tv != NULL);
if (DUK_TVAL_IS_OBJECT(tv)) {
return duk_js_isarray_hobject(DUK_TVAL_GET_OBJECT(tv));
}
return 0;
}
/*
* Array index and length
*
* Array index: E5 Section 15.4
* Array length: E5 Section 15.4.5.1 steps 3.c - 3.d (array length write)
*/
/* Compure array index from string context, or return a "not array index"
* indicator.
*/
DUK_INTERNAL duk_uarridx_t duk_js_to_arrayindex_string(const duk_uint8_t *str, duk_uint32_t blen) {
duk_uarridx_t res;
/* Only strings with byte length 1-10 can be 32-bit array indices.
* Leading zeroes (except '0' alone), plus/minus signs are not allowed.
* We could do a lot of prechecks here, but since most strings won't
* start with any digits, it's simpler to just parse the number and
* fail quickly.
*/
res = 0;
if (blen == 0) {
goto parse_fail;
}
do {
duk_uarridx_t dig;
dig = (duk_uarridx_t) (*str++) - DUK_ASC_0;
if (dig <= 9U) {
/* Careful overflow handling. When multiplying by 10:
* - 0x19999998 x 10 = 0xfffffff0: no overflow, and adding
* 0...9 is safe.
* - 0x19999999 x 10 = 0xfffffffa: no overflow, adding
* 0...5 is safe, 6...9 overflows.
* - 0x1999999a x 10 = 0x100000004: always overflow.
*/
if (DUK_UNLIKELY(res >= 0x19999999UL)) {
if (res >= 0x1999999aUL) {
/* Always overflow. */
goto parse_fail;
}
DUK_ASSERT(res == 0x19999999UL);
if (dig >= 6U) {
goto parse_fail;
}
res = 0xfffffffaUL + dig;
DUK_ASSERT(res >= 0xfffffffaUL);
DUK_ASSERT_DISABLE(res <= 0xffffffffUL); /* range */
} else {
res = res * 10U + dig;
if (DUK_UNLIKELY(res == 0)) {
/* If 'res' is 0, previous 'res' must
* have been 0 and we scanned in a zero.
* This is only allowed if blen == 1,
* i.e. the exact string '0'.
*/
if (blen == (duk_uint32_t) 1) {
return 0;
}
goto parse_fail;
}
}
} else {
/* Because 'dig' is unsigned, catches both values
* above '9' and below '0'.
*/
goto parse_fail;
}
} while (--blen > 0);
return res;
parse_fail:
return DUK_HSTRING_NO_ARRAY_INDEX;
}
#if !defined(DUK_USE_HSTRING_ARRIDX)
/* Get array index for a string which is known to be an array index. This helper
* is needed when duk_hstring doesn't concretely store the array index, but strings
* are flagged as array indices at intern time.
*/
DUK_INTERNAL duk_uarridx_t duk_js_to_arrayindex_hstring_fast_known(duk_hstring *h) {
const duk_uint8_t *p;
duk_uarridx_t res;
duk_uint8_t t;
DUK_ASSERT(h != NULL);
DUK_ASSERT(DUK_HSTRING_HAS_ARRIDX(h));
p = DUK_HSTRING_GET_DATA(h);
res = 0;
for (;;) {
t = *p++;
if (DUK_UNLIKELY(t == 0)) {
/* Scanning to NUL is always safe for interned strings. */
break;
}
DUK_ASSERT(t >= (duk_uint8_t) DUK_ASC_0 && t <= (duk_uint8_t) DUK_ASC_9);
res = res * 10U + (duk_uarridx_t) t - (duk_uarridx_t) DUK_ASC_0;
}
return res;
}
DUK_INTERNAL duk_uarridx_t duk_js_to_arrayindex_hstring_fast(duk_hstring *h) {
DUK_ASSERT(h != NULL);
if (!DUK_HSTRING_HAS_ARRIDX(h)) {
return DUK_HSTRING_NO_ARRAY_INDEX;
}
return duk_js_to_arrayindex_hstring_fast_known(h);
}
#endif /* DUK_USE_HSTRING_ARRIDX */