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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* 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 "mozilla/Utf8.h"
#include <limits>
#include "NamespaceImports.h"
#include "js/Conversions.h"
#include "js/friend/ErrorMessages.h" // JSMSG_*
#include "vm/StringType.h"
namespace js {
namespace frontend {
class ParserAtomsTable;
class TaggedParserAtomIndex;
} // namespace frontend
class GlobalObject;
class StringBuffer;
[[nodiscard]] extern bool InitRuntimeNumberState(JSRuntime* rt);
// This is a no-op if built with JS_HAS_INTL_API.
extern void FinishRuntimeNumberState(JSRuntime* rt);
/*
* 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(JSContext* cx, double d);
extern JSString* NumberToStringPure(JSContext* cx, double d);
extern JSAtom* NumberToAtom(JSContext* cx, double d);
frontend::TaggedParserAtomIndex NumberToParserAtom(
ErrorContext* ec, frontend::ParserAtomsTable& parserAtoms, double d);
template <AllowGC allowGC>
extern JSLinearString* Int32ToString(JSContext* cx, int32_t i);
extern JSLinearString* Int32ToStringPure(JSContext* cx, int32_t i);
extern JSString* Int32ToStringWithBase(JSContext* cx, int32_t i, int32_t base);
extern JSAtom* Int32ToAtom(JSContext* cx, int32_t si);
frontend::TaggedParserAtomIndex Int32ToParserAtom(
ErrorContext* ec, frontend::ParserAtomsTable& parserAtoms, int32_t si);
// ES6 15.7.3.12
extern bool IsInteger(double d);
/*
* Convert an integer or double (contained in the given value) to a string and
* append to the given buffer.
*/
[[nodiscard]] extern bool NumberValueToStringBuffer(const Value& v,
StringBuffer& sb);
extern JSLinearString* IndexToString(JSContext* cx, uint32_t index);
struct ToCStringBuf {
char sbuf[JS::MaximumNumberToStringLength] = {};
};
struct Int32ToCStringBuf {
// The amount of space large enough to store the null-terminated result of
// |ToString| on any int32.
//
// We use the same amount for uint32 (base 10 and base 16), even though uint32
// only need 11 characters (base 10) resp. 9 characters (base 16) instead of
// 12 characters for int32 in base 10.
static constexpr size_t MaximumInt32ToStringLength =
std::numeric_limits<int32_t>::digits10 +
1 + // account for the largest possible int32 value
1 + // sign for negative numbers
1 // null character
;
char sbuf[MaximumInt32ToStringLength] = {};
};
// Convert a number to a C string. This function implements ToString() as
// specified by ECMA-262-5 section 9.8.1. It handles integral values cheaply.
// Infallible: always returns a non-nullptr string.
// The optional `length` out-param is set to the string length of the result.
extern char* NumberToCString(ToCStringBuf* cbuf, double d,
size_t* length = nullptr);
extern char* Int32ToCString(Int32ToCStringBuf* cbuf, int32_t value,
size_t* length = nullptr);
extern char* Uint32ToCString(Int32ToCStringBuf* cbuf, uint32_t value,
size_t* length = nullptr);
// Like NumberToCString, but accepts only unsigned integers and uses base 16.
// Infallible: always returns a non-nullptr string.
// The optional `length` out-param is set to the string length of the result.
extern char* Uint32ToHexCString(Int32ToCStringBuf* cbuf, uint32_t value,
size_t* length = nullptr);
/*
* The largest positive integer such that all positive integers less than it
* may be precisely represented using the IEEE-754 double-precision format.
*/
constexpr double DOUBLE_INTEGRAL_PRECISION_LIMIT = uint64_t(1) << 53;
/*
* The smallest positive double such that all positive doubles larger or equal
* than it have an exact decimal representation without exponential form.
*/
constexpr double DOUBLE_DECIMAL_IN_SHORTEST_LOW = 1.0e-6;
/*
* The largest positive double such that all positive doubles less than it
* have an exact decimal representation without exponential form.
*/
constexpr double DOUBLE_DECIMAL_IN_SHORTEST_HIGH = 1.0e21;
/*
* 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);
enum class IntegerSeparatorHandling : bool { None, SkipUnderscore };
/*
* 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.
*
* The |separatorHandling| controls whether or not numeric separators can be
* part of integer string. If the option is enabled, all '_' characters in the
* string are ignored. Underscore characters must not appear directly next to
* each other, e.g. '1__2' will lead to an assertion.
*
* If [start, end) does not begin with a number with the specified base,
* *dp == 0 and *endp == start upon return.
*/
template <typename CharT>
[[nodiscard]] extern bool GetPrefixInteger(
JSContext* cx, const CharT* start, const CharT* end, int base,
IntegerSeparatorHandling separatorHandling, const CharT** endp, double* dp);
inline const char16_t* ToRawChars(const char16_t* units) { return units; }
inline const unsigned char* ToRawChars(const unsigned char* units) {
return units;
}
inline const unsigned char* ToRawChars(const mozilla::Utf8Unit* units) {
return mozilla::Utf8AsUnsignedChars(units);
}
/**
* Like GetPrefixInteger, but [start, end) must all be digits in the given
* base (and so this function doesn't take a useless outparam).
*/
template <typename CharT>
[[nodiscard]] extern bool GetFullInteger(
JSContext* cx, const CharT* start, const CharT* end, int base,
IntegerSeparatorHandling separatorHandling, double* dp) {
decltype(ToRawChars(start)) realEnd;
if (GetPrefixInteger(cx, ToRawChars(start), ToRawChars(end), base,
separatorHandling, &realEnd, dp)) {
MOZ_ASSERT(end == static_cast<const void*>(realEnd));
return true;
}
return false;
}
/*
* This is like GetPrefixInteger, but only deals with base 10, always ignores
* '_', and doesn't have an |endp| outparam. It should only be used when the
* characters are known to match |DecimalIntegerLiteral|, cf. ES2020, 11.8.3
* Numeric Literals.
*/
template <typename CharT>
[[nodiscard]] extern bool GetDecimalInteger(JSContext* cx, const CharT* start,
const CharT* end, double* dp);
/*
* This is like GetDecimalInteger, but also allows non-integer numbers. It
* should only be used when the characters are known to match |DecimalLiteral|,
* cf. ES2020, 11.8.3 Numeric Literals.
*/
template <typename CharT>
[[nodiscard]] extern bool GetDecimal(JSContext* cx, const CharT* start,
const CharT* end, double* dp);
template <typename CharT>
double CharsToNumber(const CharT* chars, size_t length);
[[nodiscard]] extern bool StringToNumber(JSContext* cx, JSString* str,
double* result);
[[nodiscard]] extern bool StringToNumberPure(JSContext* cx, JSString* str,
double* result);
// Infallible version of StringToNumber for linear strings.
extern double LinearStringToNumber(JSLinearString* str);
// Parse the input string as if Number.parseInt had been called.
extern bool NumberParseInt(JSContext* cx, JS::HandleString str, int32_t radix,
JS::MutableHandleValue result);
/* ES5 9.3 ToNumber, overwriting *vp with the appropriate number value. */
[[nodiscard]] MOZ_ALWAYS_INLINE 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;
}
bool ToNumericSlow(JSContext* cx, JS::MutableHandleValue vp);
// BigInt proposal section 3.1.6
[[nodiscard]] MOZ_ALWAYS_INLINE bool ToNumeric(JSContext* cx,
JS::MutableHandleValue vp) {
if (vp.isNumeric()) {
return true;
}
return ToNumericSlow(cx, vp);
}
bool ToInt32OrBigIntSlow(JSContext* cx, JS::MutableHandleValue vp);
[[nodiscard]] MOZ_ALWAYS_INLINE bool ToInt32OrBigInt(
JSContext* cx, JS::MutableHandleValue vp) {
if (vp.isInt32()) {
return true;
}
return ToInt32OrBigIntSlow(cx, 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.
*
* 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.
*/
template <typename CharT>
[[nodiscard]] extern double js_strtod(const CharT* begin, const CharT* end,
const CharT** dEnd);
namespace js {
/**
* Like js_strtod, but for when the number always constitutes the entire range
* (and so |dEnd| would be a value already known).
*/
template <typename CharT>
[[nodiscard]] extern double FullStringToDouble(const CharT* begin,
const CharT* end) {
decltype(ToRawChars(begin)) realEnd;
double d = js_strtod(ToRawChars(begin), ToRawChars(end), &realEnd);
MOZ_ASSERT(end == static_cast<const void*>(realEnd));
return d;
}
[[nodiscard]] extern bool ThisNumberValueForToLocaleString(JSContext* cx,
unsigned argc,
Value* vp);
[[nodiscard]] extern bool num_valueOf(JSContext* cx, unsigned argc, Value* vp);
/*
* 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::NumberEqualsInt32(v.toDouble(), &i) && i >= 0) {
*indexp = uint32_t(i);
return true;
}
if (v.isString() && v.toString()->hasIndexValue()) {
*indexp = v.toString()->getIndexValue();
return true;
}
return false;
}
// ES2020 draft rev 6b05bc56ba4e3c7a2b9922c4282d9eb844426d9b
// 7.1.5 ToInteger ( argument )
[[nodiscard]] static inline bool ToInteger(JSContext* cx, HandleValue v,
double* dp) {
if (v.isInt32()) {
*dp = v.toInt32();
return true;
}
if (v.isDouble()) {
*dp = v.toDouble();
} else if (v.isString() && v.toString()->hasIndexValue()) {
*dp = v.toString()->getIndexValue();
return true;
} 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;
}
/* ES2017 draft 7.1.17 ToIndex
*
* Return true and set |*index| to the integer value if |v| is a valid
* integer index value. Otherwise report a RangeError and return false.
*
* The returned index will always be in the range 0 <= *index <= 2^53-1.
*/
[[nodiscard]] extern bool ToIndexSlow(JSContext* cx, JS::HandleValue v,
const unsigned errorNumber,
uint64_t* index);
[[nodiscard]] static inline bool ToIndex(JSContext* cx, JS::HandleValue v,
const unsigned errorNumber,
uint64_t* index) {
if (v.isInt32()) {
int32_t i = v.toInt32();
if (i >= 0) {
*index = uint64_t(i);
return true;
}
}
return ToIndexSlow(cx, v, errorNumber, index);
}
[[nodiscard]] static inline bool ToIndex(JSContext* cx, JS::HandleValue v,
uint64_t* index) {
return ToIndex(cx, v, JSMSG_BAD_INDEX, index);
}
} /* namespace js */
#endif /* jsnum_h */