// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_CONVERSIONS_INL_H_
#define V8_CONVERSIONS_INL_H_
#include <limits.h> // Required for INT_MAX etc.
#include <math.h>
#include <float.h> // Required for DBL_MAX and on Win32 for finite()
#include <stdarg.h>
#include "globals.h" // Required for V8_INFINITY
// ----------------------------------------------------------------------------
// Extra POSIX/ANSI functions for Win32/MSVC.
#include "conversions.h"
#include "double.h"
#include "platform.h"
#include "scanner.h"
#include "strtod.h"
namespace v8 {
namespace internal {
inline double JunkStringValue() {
return BitCast<double, uint64_t>(kQuietNaNMask);
}
// The fast double-to-unsigned-int conversion routine does not guarantee
// rounding towards zero, or any reasonable value if the argument is larger
// than what fits in an unsigned 32-bit integer.
inline unsigned int FastD2UI(double x) {
// There is no unsigned version of lrint, so there is no fast path
// in this function as there is in FastD2I. Using lrint doesn't work
// for values of 2^31 and above.
// Convert "small enough" doubles to uint32_t by fixing the 32
// least significant non-fractional bits in the low 32 bits of the
// double, and reading them from there.
const double k2Pow52 = 4503599627370496.0;
bool negative = x < 0;
if (negative) {
x = -x;
}
if (x < k2Pow52) {
x += k2Pow52;
uint32_t result;
Address mantissa_ptr = reinterpret_cast<Address>(&x);
// Copy least significant 32 bits of mantissa.
memcpy(&result, mantissa_ptr, sizeof(result));
return negative ? ~result + 1 : result;
}
// Large number (outside uint32 range), Infinity or NaN.
return 0x80000000u; // Return integer indefinite.
}
inline double DoubleToInteger(double x) {
if (isnan(x)) return 0;
if (!isfinite(x) || x == 0) return x;
return (x >= 0) ? floor(x) : ceil(x);
}
int32_t DoubleToInt32(double x) {
int32_t i = FastD2I(x);
if (FastI2D(i) == x) return i;
Double d(x);
int exponent = d.Exponent();
if (exponent < 0) {
if (exponent <= -Double::kSignificandSize) return 0;
return d.Sign() * static_cast<int32_t>(d.Significand() >> -exponent);
} else {
if (exponent > 31) return 0;
return d.Sign() * static_cast<int32_t>(d.Significand() << exponent);
}
}
template <class Iterator, class EndMark>
bool SubStringEquals(Iterator* current,
EndMark end,
const char* substring) {
ASSERT(**current == *substring);
for (substring++; *substring != '\0'; substring++) {
++*current;
if (*current == end || **current != *substring) return false;
}
++*current;
return true;
}
// Returns true if a nonspace character has been found and false if the
// end was been reached before finding a nonspace character.
template <class Iterator, class EndMark>
inline bool AdvanceToNonspace(UnicodeCache* unicode_cache,
Iterator* current,
EndMark end) {
while (*current != end) {
if (!unicode_cache->IsWhiteSpace(**current)) return true;
++*current;
}
return false;
}
// Parsing integers with radix 2, 4, 8, 16, 32. Assumes current != end.
template <int radix_log_2, class Iterator, class EndMark>
double InternalStringToIntDouble(UnicodeCache* unicode_cache,
Iterator current,
EndMark end,
bool negative,
bool allow_trailing_junk) {
ASSERT(current != end);
// Skip leading 0s.
while (*current == '0') {
++current;
if (current == end) return SignedZero(negative);
}
int64_t number = 0;
int exponent = 0;
const int radix = (1 << radix_log_2);
do {
int digit;
if (*current >= '0' && *current <= '9' && *current < '0' + radix) {
digit = static_cast<char>(*current) - '0';
} else if (radix > 10 && *current >= 'a' && *current < 'a' + radix - 10) {
digit = static_cast<char>(*current) - 'a' + 10;
} else if (radix > 10 && *current >= 'A' && *current < 'A' + radix - 10) {
digit = static_cast<char>(*current) - 'A' + 10;
} else {
if (allow_trailing_junk ||
!AdvanceToNonspace(unicode_cache, ¤t, end)) {
break;
} else {
return JunkStringValue();
}
}
number = number * radix + digit;
int overflow = static_cast<int>(number >> 53);
if (overflow != 0) {
// Overflow occurred. Need to determine which direction to round the
// result.
int overflow_bits_count = 1;
while (overflow > 1) {
overflow_bits_count++;
overflow >>= 1;
}
int dropped_bits_mask = ((1 << overflow_bits_count) - 1);
int dropped_bits = static_cast<int>(number) & dropped_bits_mask;
number >>= overflow_bits_count;
exponent = overflow_bits_count;
bool zero_tail = true;
while (true) {
++current;
if (current == end || !isDigit(*current, radix)) break;
zero_tail = zero_tail && *current == '0';
exponent += radix_log_2;
}
if (!allow_trailing_junk &&
AdvanceToNonspace(unicode_cache, ¤t, end)) {
return JunkStringValue();
}
int middle_value = (1 << (overflow_bits_count - 1));
if (dropped_bits > middle_value) {
number++; // Rounding up.
} else if (dropped_bits == middle_value) {
// Rounding to even to consistency with decimals: half-way case rounds
// up if significant part is odd and down otherwise.
if ((number & 1) != 0 || !zero_tail) {
number++; // Rounding up.
}
}
// Rounding up may cause overflow.
if ((number & ((int64_t)1 << 53)) != 0) {
exponent++;
number >>= 1;
}
break;
}
++current;
} while (current != end);
ASSERT(number < ((int64_t)1 << 53));
ASSERT(static_cast<int64_t>(static_cast<double>(number)) == number);
if (exponent == 0) {
if (negative) {
if (number == 0) return -0.0;
number = -number;
}
return static_cast<double>(number);
}
ASSERT(number != 0);
// The double could be constructed faster from number (mantissa), exponent
// and sign. Assuming it's a rare case more simple code is used.
return static_cast<double>(negative ? -number : number) * pow(2.0, exponent);
}
template <class Iterator, class EndMark>
double InternalStringToInt(UnicodeCache* unicode_cache,
Iterator current,
EndMark end,
int radix) {
const bool allow_trailing_junk = true;
const double empty_string_val = JunkStringValue();
if (!AdvanceToNonspace(unicode_cache, ¤t, end)) {
return empty_string_val;
}
bool negative = false;
bool leading_zero = false;
if (*current == '+') {
// Ignore leading sign; skip following spaces.
++current;
if (current == end) {
return JunkStringValue();
}
} else if (*current == '-') {
++current;
if (current == end) {
return JunkStringValue();
}
negative = true;
}
if (radix == 0) {
// Radix detection.
if (*current == '0') {
++current;
if (current == end) return SignedZero(negative);
if (*current == 'x' || *current == 'X') {
radix = 16;
++current;
if (current == end) return JunkStringValue();
} else {
radix = 8;
leading_zero = true;
}
} else {
radix = 10;
}
} else if (radix == 16) {
if (*current == '0') {
// Allow "0x" prefix.
++current;
if (current == end) return SignedZero(negative);
if (*current == 'x' || *current == 'X') {
++current;
if (current == end) return JunkStringValue();
} else {
leading_zero = true;
}
}
}
if (radix < 2 || radix > 36) return JunkStringValue();
// Skip leading zeros.
while (*current == '0') {
leading_zero = true;
++current;
if (current == end) return SignedZero(negative);
}
if (!leading_zero && !isDigit(*current, radix)) {
return JunkStringValue();
}
if (IsPowerOf2(radix)) {
switch (radix) {
case 2:
return InternalStringToIntDouble<1>(
unicode_cache, current, end, negative, allow_trailing_junk);
case 4:
return InternalStringToIntDouble<2>(
unicode_cache, current, end, negative, allow_trailing_junk);
case 8:
return InternalStringToIntDouble<3>(
unicode_cache, current, end, negative, allow_trailing_junk);
case 16:
return InternalStringToIntDouble<4>(
unicode_cache, current, end, negative, allow_trailing_junk);
case 32:
return InternalStringToIntDouble<5>(
unicode_cache, current, end, negative, allow_trailing_junk);
default:
UNREACHABLE();
}
}
if (radix == 10) {
// Parsing with strtod.
const int kMaxSignificantDigits = 309; // Doubles are less than 1.8e308.
// The buffer may contain up to kMaxSignificantDigits + 1 digits and a zero
// end.
const int kBufferSize = kMaxSignificantDigits + 2;
char buffer[kBufferSize];
int buffer_pos = 0;
while (*current >= '0' && *current <= '9') {
if (buffer_pos <= kMaxSignificantDigits) {
// If the number has more than kMaxSignificantDigits it will be parsed
// as infinity.
ASSERT(buffer_pos < kBufferSize);
buffer[buffer_pos++] = static_cast<char>(*current);
}
++current;
if (current == end) break;
}
if (!allow_trailing_junk &&
AdvanceToNonspace(unicode_cache, ¤t, end)) {
return JunkStringValue();
}
ASSERT(buffer_pos < kBufferSize);
buffer[buffer_pos] = '\0';
Vector<const char> buffer_vector(buffer, buffer_pos);
return negative ? -Strtod(buffer_vector, 0) : Strtod(buffer_vector, 0);
}
// The following code causes accumulating rounding error for numbers greater
// than ~2^56. It's explicitly allowed in the spec: "if R is not 2, 4, 8, 10,
// 16, or 32, then mathInt may be an implementation-dependent approximation to
// the mathematical integer value" (15.1.2.2).
int lim_0 = '0' + (radix < 10 ? radix : 10);
int lim_a = 'a' + (radix - 10);
int lim_A = 'A' + (radix - 10);
// NOTE: The code for computing the value may seem a bit complex at
// first glance. It is structured to use 32-bit multiply-and-add
// loops as long as possible to avoid loosing precision.
double v = 0.0;
bool done = false;
do {
// Parse the longest part of the string starting at index j
// possible while keeping the multiplier, and thus the part
// itself, within 32 bits.
unsigned int part = 0, multiplier = 1;
while (true) {
int d;
if (*current >= '0' && *current < lim_0) {
d = *current - '0';
} else if (*current >= 'a' && *current < lim_a) {
d = *current - 'a' + 10;
} else if (*current >= 'A' && *current < lim_A) {
d = *current - 'A' + 10;
} else {
done = true;
break;
}
// Update the value of the part as long as the multiplier fits
// in 32 bits. When we can't guarantee that the next iteration
// will not overflow the multiplier, we stop parsing the part
// by leaving the loop.
const unsigned int kMaximumMultiplier = 0xffffffffU / 36;
uint32_t m = multiplier * radix;
if (m > kMaximumMultiplier) break;
part = part * radix + d;
multiplier = m;
ASSERT(multiplier > part);
++current;
if (current == end) {
done = true;
break;
}
}
// Update the value and skip the part in the string.
v = v * multiplier + part;
} while (!done);
if (!allow_trailing_junk &&
AdvanceToNonspace(unicode_cache, ¤t, end)) {
return JunkStringValue();
}
return negative ? -v : v;
}
// Converts a string to a double value. Assumes the Iterator supports
// the following operations:
// 1. current == end (other ops are not allowed), current != end.
// 2. *current - gets the current character in the sequence.
// 3. ++current (advances the position).
template <class Iterator, class EndMark>
double InternalStringToDouble(UnicodeCache* unicode_cache,
Iterator current,
EndMark end,
int flags,
double empty_string_val) {
// To make sure that iterator dereferencing is valid the following
// convention is used:
// 1. Each '++current' statement is followed by check for equality to 'end'.
// 2. If AdvanceToNonspace returned false then current == end.
// 3. If 'current' becomes be equal to 'end' the function returns or goes to
// 'parsing_done'.
// 4. 'current' is not dereferenced after the 'parsing_done' label.
// 5. Code before 'parsing_done' may rely on 'current != end'.
if (!AdvanceToNonspace(unicode_cache, ¤t, end)) {
return empty_string_val;
}
const bool allow_trailing_junk = (flags & ALLOW_TRAILING_JUNK) != 0;
// The longest form of simplified number is: "-<significant digits>'.1eXXX\0".
const int kBufferSize = kMaxSignificantDigits + 10;
char buffer[kBufferSize]; // NOLINT: size is known at compile time.
int buffer_pos = 0;
// Exponent will be adjusted if insignificant digits of the integer part
// or insignificant leading zeros of the fractional part are dropped.
int exponent = 0;
int significant_digits = 0;
int insignificant_digits = 0;
bool nonzero_digit_dropped = false;
bool negative = false;
if (*current == '+') {
// Ignore leading sign.
++current;
if (current == end) return JunkStringValue();
} else if (*current == '-') {
++current;
if (current == end) return JunkStringValue();
negative = true;
}
static const char kInfinitySymbol[] = "Infinity";
if (*current == kInfinitySymbol[0]) {
if (!SubStringEquals(¤t, end, kInfinitySymbol)) {
return JunkStringValue();
}
if (!allow_trailing_junk &&
AdvanceToNonspace(unicode_cache, ¤t, end)) {
return JunkStringValue();
}
ASSERT(buffer_pos == 0);
return negative ? -V8_INFINITY : V8_INFINITY;
}
bool leading_zero = false;
if (*current == '0') {
++current;
if (current == end) return SignedZero(negative);
leading_zero = true;
// It could be hexadecimal value.
if ((flags & ALLOW_HEX) && (*current == 'x' || *current == 'X')) {
++current;
if (current == end || !isDigit(*current, 16)) {
return JunkStringValue(); // "0x".
}
return InternalStringToIntDouble<4>(unicode_cache,
current,
end,
negative,
allow_trailing_junk);
}
// Ignore leading zeros in the integer part.
while (*current == '0') {
++current;
if (current == end) return SignedZero(negative);
}
}
bool octal = leading_zero && (flags & ALLOW_OCTALS) != 0;
// Copy significant digits of the integer part (if any) to the buffer.
while (*current >= '0' && *current <= '9') {
if (significant_digits < kMaxSignificantDigits) {
ASSERT(buffer_pos < kBufferSize);
buffer[buffer_pos++] = static_cast<char>(*current);
significant_digits++;
// Will later check if it's an octal in the buffer.
} else {
insignificant_digits++; // Move the digit into the exponential part.
nonzero_digit_dropped = nonzero_digit_dropped || *current != '0';
}
octal = octal && *current < '8';
++current;
if (current == end) goto parsing_done;
}
if (significant_digits == 0) {
octal = false;
}
if (*current == '.') {
if (octal && !allow_trailing_junk) return JunkStringValue();
if (octal) goto parsing_done;
++current;
if (current == end) {
if (significant_digits == 0 && !leading_zero) {
return JunkStringValue();
} else {
goto parsing_done;
}
}
if (significant_digits == 0) {
// octal = false;
// Integer part consists of 0 or is absent. Significant digits start after
// leading zeros (if any).
while (*current == '0') {
++current;
if (current == end) return SignedZero(negative);
exponent--; // Move this 0 into the exponent.
}
}
// There is a fractional part. We don't emit a '.', but adjust the exponent
// instead.
while (*current >= '0' && *current <= '9') {
if (significant_digits < kMaxSignificantDigits) {
ASSERT(buffer_pos < kBufferSize);
buffer[buffer_pos++] = static_cast<char>(*current);
significant_digits++;
exponent--;
} else {
// Ignore insignificant digits in the fractional part.
nonzero_digit_dropped = nonzero_digit_dropped || *current != '0';
}
++current;
if (current == end) goto parsing_done;
}
}
if (!leading_zero && exponent == 0 && significant_digits == 0) {
// If leading_zeros is true then the string contains zeros.
// If exponent < 0 then string was [+-]\.0*...
// If significant_digits != 0 the string is not equal to 0.
// Otherwise there are no digits in the string.
return JunkStringValue();
}
// Parse exponential part.
if (*current == 'e' || *current == 'E') {
if (octal) return JunkStringValue();
++current;
if (current == end) {
if (allow_trailing_junk) {
goto parsing_done;
} else {
return JunkStringValue();
}
}
char sign = '+';
if (*current == '+' || *current == '-') {
sign = static_cast<char>(*current);
++current;
if (current == end) {
if (allow_trailing_junk) {
goto parsing_done;
} else {
return JunkStringValue();
}
}
}
if (current == end || *current < '0' || *current > '9') {
if (allow_trailing_junk) {
goto parsing_done;
} else {
return JunkStringValue();
}
}
const int max_exponent = INT_MAX / 2;
ASSERT(-max_exponent / 2 <= exponent && exponent <= max_exponent / 2);
int num = 0;
do {
// Check overflow.
int digit = *current - '0';
if (num >= max_exponent / 10
&& !(num == max_exponent / 10 && digit <= max_exponent % 10)) {
num = max_exponent;
} else {
num = num * 10 + digit;
}
++current;
} while (current != end && *current >= '0' && *current <= '9');
exponent += (sign == '-' ? -num : num);
}
if (!allow_trailing_junk &&
AdvanceToNonspace(unicode_cache, ¤t, end)) {
return JunkStringValue();
}
parsing_done:
exponent += insignificant_digits;
if (octal) {
return InternalStringToIntDouble<3>(unicode_cache,
buffer,
buffer + buffer_pos,
negative,
allow_trailing_junk);
}
if (nonzero_digit_dropped) {
buffer[buffer_pos++] = '1';
exponent--;
}
ASSERT(buffer_pos < kBufferSize);
buffer[buffer_pos] = '\0';
double converted = Strtod(Vector<const char>(buffer, buffer_pos), exponent);
return negative ? -converted : converted;
}
} } // namespace v8::internal
#endif // V8_CONVERSIONS_INL_H_