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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /js/src/jsnum.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'js/src/jsnum.h')
-rw-r--r-- | js/src/jsnum.h | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/js/src/jsnum.h b/js/src/jsnum.h new file mode 100644 index 000000000..62b3d617f --- /dev/null +++ b/js/src/jsnum.h @@ -0,0 +1,356 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * vim: set ts=8 sts=4 et sw=4 tw=99: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef jsnum_h +#define jsnum_h + +#include "mozilla/FloatingPoint.h" +#include "mozilla/Range.h" + +#include "NamespaceImports.h" + +#include "js/Conversions.h" + + +// This macro is should be `one' if current compiler supports builtin functions +// like __builtin_sadd_overflow. +#if __GNUC__ >= 5 + // GCC 5 and above supports these functions. + #define BUILTIN_CHECKED_ARITHMETIC_SUPPORTED(x) 1 +#else + // For CLANG, we use its own function to check for this. + #ifdef __has_builtin + #define BUILTIN_CHECKED_ARITHMETIC_SUPPORTED(x) __has_builtin(x) + #endif +#endif +#ifndef BUILTIN_CHECKED_ARITHMETIC_SUPPORTED + #define BUILTIN_CHECKED_ARITHMETIC_SUPPORTED(x) 0 +#endif + +namespace js { + +class StringBuffer; + +extern MOZ_MUST_USE bool +InitRuntimeNumberState(JSRuntime* rt); + +#if !EXPOSE_INTL_API +extern void +FinishRuntimeNumberState(JSRuntime* rt); +#endif + +/* Initialize the Number class, returning its prototype object. */ +extern JSObject* +InitNumberClass(JSContext* cx, HandleObject obj); + +} /* namespace js */ + +/* + * String constants for global function names, used in jsapi.c and jsnum.c. + */ +extern const char js_isNaN_str[]; +extern const char js_isFinite_str[]; +extern const char js_parseFloat_str[]; +extern const char js_parseInt_str[]; + +class JSAtom; + +namespace js { + +/* + * When base == 10, this function implements ToString() as specified by + * ECMA-262-5 section 9.8.1; but note that it handles integers specially for + * performance. See also js::NumberToCString(). + */ +template <AllowGC allowGC> +extern JSString* +NumberToString(ExclusiveContext* cx, double d); + +extern JSAtom* +NumberToAtom(ExclusiveContext* cx, double d); + +template <AllowGC allowGC> +extern JSFlatString* +Int32ToString(ExclusiveContext* cx, int32_t i); + +extern JSAtom* +Int32ToAtom(ExclusiveContext* cx, int32_t si); + +/* + * Convert an integer or double (contained in the given value) to a string and + * append to the given buffer. + */ +extern MOZ_MUST_USE bool JS_FASTCALL +NumberValueToStringBuffer(JSContext* cx, const Value& v, StringBuffer& sb); + +/* Same as js_NumberToString, different signature. */ +extern JSFlatString* +NumberToString(JSContext* cx, double d); + +extern JSFlatString* +IndexToString(JSContext* cx, uint32_t index); + +/* + * Usually a small amount of static storage is enough, but sometimes we need + * to dynamically allocate much more. This struct encapsulates that. + * Dynamically allocated memory will be freed when the object is destroyed. + */ +struct ToCStringBuf +{ + /* + * The longest possible result that would need to fit in sbuf is + * (-0x80000000).toString(2), which has length 33. Longer cases are + * possible, but they'll go in dbuf. + */ + static const size_t sbufSize = 34; + char sbuf[sbufSize]; + char* dbuf; + + ToCStringBuf(); + ~ToCStringBuf(); +}; + +/* + * Convert a number to a C string. When base==10, this function implements + * ToString() as specified by ECMA-262-5 section 9.8.1. It handles integral + * values cheaply. Return nullptr if we ran out of memory. See also + * NumberToCString(). + */ +extern char* +NumberToCString(JSContext* cx, ToCStringBuf* cbuf, double d, int base = 10); + +/* + * The largest positive integer such that all positive integers less than it + * may be precisely represented using the IEEE-754 double-precision format. + */ +const double DOUBLE_INTEGRAL_PRECISION_LIMIT = uint64_t(1) << 53; + +/* + * Parse a decimal number encoded in |chars|. The decimal number must be + * sufficiently small that it will not overflow the integrally-precise range of + * the double type -- that is, the number will be smaller than + * DOUBLE_INTEGRAL_PRECISION_LIMIT + */ +template <typename CharT> +extern double +ParseDecimalNumber(const mozilla::Range<const CharT> chars); + +/* + * Compute the positive integer of the given base described immediately at the + * start of the range [start, end) -- no whitespace-skipping, no magical + * leading-"0" octal or leading-"0x" hex behavior, no "+"/"-" parsing, just + * reading the digits of the integer. Return the index one past the end of the + * digits of the integer in *endp, and return the integer itself in *dp. If + * base is 10 or a power of two the returned integer is the closest possible + * double; otherwise extremely large integers may be slightly inaccurate. + * + * If [start, end) does not begin with a number with the specified base, + * *dp == 0 and *endp == start upon return. + */ +template <typename CharT> +extern MOZ_MUST_USE bool +GetPrefixInteger(ExclusiveContext* cx, const CharT* start, const CharT* end, int base, + const CharT** endp, double* dp); + +/* + * This is like GetPrefixInteger, but only deals with base 10, and doesn't have + * and |endp| outparam. It should only be used when the characters are known to + * only contain digits. + */ +extern MOZ_MUST_USE bool +GetDecimalInteger(ExclusiveContext* cx, const char16_t* start, const char16_t* end, double* dp); + +extern MOZ_MUST_USE bool +StringToNumber(ExclusiveContext* cx, JSString* str, double* result); + +/* ES5 9.3 ToNumber, overwriting *vp with the appropriate number value. */ +MOZ_ALWAYS_INLINE MOZ_MUST_USE bool +ToNumber(JSContext* cx, JS::MutableHandleValue vp) +{ + if (vp.isNumber()) + return true; + double d; + extern JS_PUBLIC_API(bool) ToNumberSlow(JSContext* cx, HandleValue v, double* dp); + if (!ToNumberSlow(cx, vp, &d)) + return false; + + vp.setNumber(d); + return true; +} + +MOZ_MUST_USE bool +num_parseInt(JSContext* cx, unsigned argc, Value* vp); + +} /* namespace js */ + +/* + * Similar to strtod except that it replaces overflows with infinities of the + * correct sign, and underflows with zeros of the correct sign. Guaranteed to + * return the closest double number to the given input in dp. + * + * Also allows inputs of the form [+|-]Infinity, which produce an infinity of + * the appropriate sign. The case of the "Infinity" string must match exactly. + * If the string does not contain a number, set *dEnd to begin and return 0.0 + * in *d. + * + * Return false if out of memory. + */ +template <typename CharT> +extern MOZ_MUST_USE bool +js_strtod(js::ExclusiveContext* cx, const CharT* begin, const CharT* end, + const CharT** dEnd, double* d); + +namespace js { + +extern MOZ_MUST_USE bool +num_toString(JSContext* cx, unsigned argc, Value* vp); + +extern MOZ_MUST_USE bool +num_valueOf(JSContext* cx, unsigned argc, Value* vp); + +static MOZ_ALWAYS_INLINE bool +ValueFitsInInt32(const Value& v, int32_t* pi) +{ + if (v.isInt32()) { + *pi = v.toInt32(); + return true; + } + return v.isDouble() && mozilla::NumberIsInt32(v.toDouble(), pi); +} + +/* + * Returns true if the given value is definitely an index: that is, the value + * is a number that's an unsigned 32-bit integer. + * + * This method prioritizes common-case speed over accuracy in every case. It + * can produce false negatives (but not false positives): some values which are + * indexes will be reported not to be indexes by this method. Users must + * consider this possibility when using this method. + */ +static MOZ_ALWAYS_INLINE bool +IsDefinitelyIndex(const Value& v, uint32_t* indexp) +{ + if (v.isInt32() && v.toInt32() >= 0) { + *indexp = v.toInt32(); + return true; + } + + int32_t i; + if (v.isDouble() && mozilla::NumberIsInt32(v.toDouble(), &i) && i >= 0) { + *indexp = uint32_t(i); + return true; + } + + return false; +} + +/* ES5 9.4 ToInteger. */ +static MOZ_MUST_USE inline bool +ToInteger(JSContext* cx, HandleValue v, double* dp) +{ + if (v.isInt32()) { + *dp = v.toInt32(); + return true; + } + if (v.isDouble()) { + *dp = v.toDouble(); + } else { + extern JS_PUBLIC_API(bool) ToNumberSlow(JSContext* cx, HandleValue v, double* dp); + if (!ToNumberSlow(cx, v, dp)) + return false; + } + *dp = JS::ToInteger(*dp); + return true; +} + +/* ES6 7.1.15 ToLength, but clamped to the [0,2^32-2] range. If the + * return value is false then *overflow will be true iff the value was + * not clampable to uint32_t range. + * + * For JSContext and ExclusiveContext. + */ +template<typename T> +MOZ_MUST_USE bool ToLengthClamped(T* cx, HandleValue v, uint32_t* out, bool* overflow); + +/* Convert and range check an index value as for DataView, SIMD, and Atomics + * operations, eg ES7 24.2.1.1, DataView's GetViewValue(): + * + * 1. numericIndex = ToNumber(argument) (may throw TypeError) + * 2. intIndex = ToInteger(numericIndex) + * 3. if intIndex != numericIndex throw RangeError + * + * This function additionally bounds the range to the non-negative contiguous + * integers: + * + * 4. if intIndex < 0 or intIndex > 2^53 throw RangeError + * + * Return true and set |*index| to the integer value if |argument| is a valid + * array index argument. Otherwise report an TypeError or RangeError and return + * false. + * + * The returned index will always be in the range 0 <= *index <= 2^53. + */ +MOZ_MUST_USE bool ToIntegerIndex(JSContext* cx, JS::HandleValue v, uint64_t* index); + +MOZ_MUST_USE inline bool +SafeAdd(int32_t one, int32_t two, int32_t* res) +{ +#if BUILTIN_CHECKED_ARITHMETIC_SUPPORTED(__builtin_sadd_overflow) + // Using compiler's builtin function. + return !__builtin_sadd_overflow(one, two, res); +#else + // Use unsigned for the 32-bit operation since signed overflow gets + // undefined behavior. + *res = uint32_t(one) + uint32_t(two); + int64_t ores = (int64_t)one + (int64_t)two; + return ores == (int64_t)*res; +#endif +} + +MOZ_MUST_USE inline bool +SafeSub(int32_t one, int32_t two, int32_t* res) +{ +#if BUILTIN_CHECKED_ARITHMETIC_SUPPORTED(__builtin_ssub_overflow) + return !__builtin_ssub_overflow(one, two, res); +#else + *res = uint32_t(one) - uint32_t(two); + int64_t ores = (int64_t)one - (int64_t)two; + return ores == (int64_t)*res; +#endif +} + +MOZ_MUST_USE inline bool +SafeMul(int32_t one, int32_t two, int32_t* res) +{ +#if BUILTIN_CHECKED_ARITHMETIC_SUPPORTED(__builtin_smul_overflow) + return !__builtin_smul_overflow(one, two, res); +#else + *res = uint32_t(one) * uint32_t(two); + int64_t ores = (int64_t)one * (int64_t)two; + return ores == (int64_t)*res; +#endif +} + +extern MOZ_MUST_USE bool +ToNumberSlow(ExclusiveContext* cx, HandleValue v, double* dp); + +// Variant of ToNumber which takes an ExclusiveContext instead of a JSContext. +// ToNumber is part of the API and can't use ExclusiveContext directly. +MOZ_ALWAYS_INLINE MOZ_MUST_USE bool +ToNumber(ExclusiveContext* cx, HandleValue v, double* out) +{ + if (v.isNumber()) { + *out = v.toNumber(); + return true; + } + return ToNumberSlow(cx, v, out); +} + +void FIX_FPU(); + +} /* namespace js */ + +#endif /* jsnum_h */ |