| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/conversions.h" |
| |
| #include <limits.h> |
| #include <stdarg.h> |
| #include <cmath> |
| |
| #include "src/allocation.h" |
| #include "src/assert-scope.h" |
| #include "src/char-predicates-inl.h" |
| #include "src/codegen.h" |
| #include "src/conversions-inl.h" |
| #include "src/dtoa.h" |
| #include "src/factory.h" |
| #include "src/handles.h" |
| #include "src/list-inl.h" |
| #include "src/strtod.h" |
| #include "src/utils.h" |
| |
| #ifndef _STLP_VENDOR_CSTD |
| // STLPort doesn't import fpclassify into the std namespace. |
| using std::fpclassify; |
| #endif |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| namespace { |
| |
| // C++-style iterator adaptor for StringCharacterStream |
| // (unlike C++ iterators the end-marker has different type). |
| class StringCharacterStreamIterator { |
| public: |
| class EndMarker {}; |
| |
| explicit StringCharacterStreamIterator(StringCharacterStream* stream); |
| |
| uint16_t operator*() const; |
| void operator++(); |
| bool operator==(EndMarker const&) const { return end_; } |
| bool operator!=(EndMarker const& m) const { return !end_; } |
| |
| private: |
| StringCharacterStream* const stream_; |
| uint16_t current_; |
| bool end_; |
| }; |
| |
| |
| StringCharacterStreamIterator::StringCharacterStreamIterator( |
| StringCharacterStream* stream) : stream_(stream) { |
| ++(*this); |
| } |
| |
| uint16_t StringCharacterStreamIterator::operator*() const { |
| return current_; |
| } |
| |
| |
| void StringCharacterStreamIterator::operator++() { |
| end_ = !stream_->HasMore(); |
| if (!end_) { |
| current_ = stream_->GetNext(); |
| } |
| } |
| } // End anonymous namespace. |
| |
| |
| double StringToDouble(UnicodeCache* unicode_cache, |
| const char* str, int flags, double empty_string_val) { |
| // We cast to const uint8_t* here to avoid instantiating the |
| // InternalStringToDouble() template for const char* as well. |
| const uint8_t* start = reinterpret_cast<const uint8_t*>(str); |
| const uint8_t* end = start + StrLength(str); |
| return InternalStringToDouble(unicode_cache, start, end, flags, |
| empty_string_val); |
| } |
| |
| |
| double StringToDouble(UnicodeCache* unicode_cache, |
| Vector<const uint8_t> str, |
| int flags, |
| double empty_string_val) { |
| // We cast to const uint8_t* here to avoid instantiating the |
| // InternalStringToDouble() template for const char* as well. |
| const uint8_t* start = reinterpret_cast<const uint8_t*>(str.start()); |
| const uint8_t* end = start + str.length(); |
| return InternalStringToDouble(unicode_cache, start, end, flags, |
| empty_string_val); |
| } |
| |
| |
| double StringToDouble(UnicodeCache* unicode_cache, |
| Vector<const uc16> str, |
| int flags, |
| double empty_string_val) { |
| const uc16* end = str.start() + str.length(); |
| return InternalStringToDouble(unicode_cache, str.start(), end, flags, |
| empty_string_val); |
| } |
| |
| |
| // Converts a string into an integer. |
| double StringToInt(UnicodeCache* unicode_cache, |
| Vector<const uint8_t> vector, |
| int radix) { |
| return InternalStringToInt( |
| unicode_cache, vector.start(), vector.start() + vector.length(), radix); |
| } |
| |
| |
| double StringToInt(UnicodeCache* unicode_cache, |
| Vector<const uc16> vector, |
| int radix) { |
| return InternalStringToInt( |
| unicode_cache, vector.start(), vector.start() + vector.length(), radix); |
| } |
| |
| |
| const char* DoubleToCString(double v, Vector<char> buffer) { |
| switch (fpclassify(v)) { |
| case FP_NAN: return "NaN"; |
| case FP_INFINITE: return (v < 0.0 ? "-Infinity" : "Infinity"); |
| case FP_ZERO: return "0"; |
| default: { |
| SimpleStringBuilder builder(buffer.start(), buffer.length()); |
| int decimal_point; |
| int sign; |
| const int kV8DtoaBufferCapacity = kBase10MaximalLength + 1; |
| char decimal_rep[kV8DtoaBufferCapacity]; |
| int length; |
| |
| DoubleToAscii(v, DTOA_SHORTEST, 0, |
| Vector<char>(decimal_rep, kV8DtoaBufferCapacity), |
| &sign, &length, &decimal_point); |
| |
| if (sign) builder.AddCharacter('-'); |
| |
| if (length <= decimal_point && decimal_point <= 21) { |
| // ECMA-262 section 9.8.1 step 6. |
| builder.AddString(decimal_rep); |
| builder.AddPadding('0', decimal_point - length); |
| |
| } else if (0 < decimal_point && decimal_point <= 21) { |
| // ECMA-262 section 9.8.1 step 7. |
| builder.AddSubstring(decimal_rep, decimal_point); |
| builder.AddCharacter('.'); |
| builder.AddString(decimal_rep + decimal_point); |
| |
| } else if (decimal_point <= 0 && decimal_point > -6) { |
| // ECMA-262 section 9.8.1 step 8. |
| builder.AddString("0."); |
| builder.AddPadding('0', -decimal_point); |
| builder.AddString(decimal_rep); |
| |
| } else { |
| // ECMA-262 section 9.8.1 step 9 and 10 combined. |
| builder.AddCharacter(decimal_rep[0]); |
| if (length != 1) { |
| builder.AddCharacter('.'); |
| builder.AddString(decimal_rep + 1); |
| } |
| builder.AddCharacter('e'); |
| builder.AddCharacter((decimal_point >= 0) ? '+' : '-'); |
| int exponent = decimal_point - 1; |
| if (exponent < 0) exponent = -exponent; |
| builder.AddDecimalInteger(exponent); |
| } |
| return builder.Finalize(); |
| } |
| } |
| } |
| |
| |
| const char* IntToCString(int n, Vector<char> buffer) { |
| bool negative = false; |
| if (n < 0) { |
| // We must not negate the most negative int. |
| if (n == kMinInt) return DoubleToCString(n, buffer); |
| negative = true; |
| n = -n; |
| } |
| // Build the string backwards from the least significant digit. |
| int i = buffer.length(); |
| buffer[--i] = '\0'; |
| do { |
| buffer[--i] = '0' + (n % 10); |
| n /= 10; |
| } while (n); |
| if (negative) buffer[--i] = '-'; |
| return buffer.start() + i; |
| } |
| |
| |
| char* DoubleToFixedCString(double value, int f) { |
| const int kMaxDigitsBeforePoint = 21; |
| const double kFirstNonFixed = 1e21; |
| const int kMaxDigitsAfterPoint = 20; |
| DCHECK(f >= 0); |
| DCHECK(f <= kMaxDigitsAfterPoint); |
| |
| bool negative = false; |
| double abs_value = value; |
| if (value < 0) { |
| abs_value = -value; |
| negative = true; |
| } |
| |
| // If abs_value has more than kMaxDigitsBeforePoint digits before the point |
| // use the non-fixed conversion routine. |
| if (abs_value >= kFirstNonFixed) { |
| char arr[100]; |
| Vector<char> buffer(arr, arraysize(arr)); |
| return StrDup(DoubleToCString(value, buffer)); |
| } |
| |
| // Find a sufficiently precise decimal representation of n. |
| int decimal_point; |
| int sign; |
| // Add space for the '\0' byte. |
| const int kDecimalRepCapacity = |
| kMaxDigitsBeforePoint + kMaxDigitsAfterPoint + 1; |
| char decimal_rep[kDecimalRepCapacity]; |
| int decimal_rep_length; |
| DoubleToAscii(value, DTOA_FIXED, f, |
| Vector<char>(decimal_rep, kDecimalRepCapacity), |
| &sign, &decimal_rep_length, &decimal_point); |
| |
| // Create a representation that is padded with zeros if needed. |
| int zero_prefix_length = 0; |
| int zero_postfix_length = 0; |
| |
| if (decimal_point <= 0) { |
| zero_prefix_length = -decimal_point + 1; |
| decimal_point = 1; |
| } |
| |
| if (zero_prefix_length + decimal_rep_length < decimal_point + f) { |
| zero_postfix_length = decimal_point + f - decimal_rep_length - |
| zero_prefix_length; |
| } |
| |
| unsigned rep_length = |
| zero_prefix_length + decimal_rep_length + zero_postfix_length; |
| SimpleStringBuilder rep_builder(rep_length + 1); |
| rep_builder.AddPadding('0', zero_prefix_length); |
| rep_builder.AddString(decimal_rep); |
| rep_builder.AddPadding('0', zero_postfix_length); |
| char* rep = rep_builder.Finalize(); |
| |
| // Create the result string by appending a minus and putting in a |
| // decimal point if needed. |
| unsigned result_size = decimal_point + f + 2; |
| SimpleStringBuilder builder(result_size + 1); |
| if (negative) builder.AddCharacter('-'); |
| builder.AddSubstring(rep, decimal_point); |
| if (f > 0) { |
| builder.AddCharacter('.'); |
| builder.AddSubstring(rep + decimal_point, f); |
| } |
| DeleteArray(rep); |
| return builder.Finalize(); |
| } |
| |
| |
| static char* CreateExponentialRepresentation(char* decimal_rep, |
| int exponent, |
| bool negative, |
| int significant_digits) { |
| bool negative_exponent = false; |
| if (exponent < 0) { |
| negative_exponent = true; |
| exponent = -exponent; |
| } |
| |
| // Leave room in the result for appending a minus, for a period, the |
| // letter 'e', a minus or a plus depending on the exponent, and a |
| // three digit exponent. |
| unsigned result_size = significant_digits + 7; |
| SimpleStringBuilder builder(result_size + 1); |
| |
| if (negative) builder.AddCharacter('-'); |
| builder.AddCharacter(decimal_rep[0]); |
| if (significant_digits != 1) { |
| builder.AddCharacter('.'); |
| builder.AddString(decimal_rep + 1); |
| int rep_length = StrLength(decimal_rep); |
| builder.AddPadding('0', significant_digits - rep_length); |
| } |
| |
| builder.AddCharacter('e'); |
| builder.AddCharacter(negative_exponent ? '-' : '+'); |
| builder.AddDecimalInteger(exponent); |
| return builder.Finalize(); |
| } |
| |
| |
| char* DoubleToExponentialCString(double value, int f) { |
| const int kMaxDigitsAfterPoint = 20; |
| // f might be -1 to signal that f was undefined in JavaScript. |
| DCHECK(f >= -1 && f <= kMaxDigitsAfterPoint); |
| |
| bool negative = false; |
| if (value < 0) { |
| value = -value; |
| negative = true; |
| } |
| |
| // Find a sufficiently precise decimal representation of n. |
| int decimal_point; |
| int sign; |
| // f corresponds to the digits after the point. There is always one digit |
| // before the point. The number of requested_digits equals hence f + 1. |
| // And we have to add one character for the null-terminator. |
| const int kV8DtoaBufferCapacity = kMaxDigitsAfterPoint + 1 + 1; |
| // Make sure that the buffer is big enough, even if we fall back to the |
| // shortest representation (which happens when f equals -1). |
| DCHECK(kBase10MaximalLength <= kMaxDigitsAfterPoint + 1); |
| char decimal_rep[kV8DtoaBufferCapacity]; |
| int decimal_rep_length; |
| |
| if (f == -1) { |
| DoubleToAscii(value, DTOA_SHORTEST, 0, |
| Vector<char>(decimal_rep, kV8DtoaBufferCapacity), |
| &sign, &decimal_rep_length, &decimal_point); |
| f = decimal_rep_length - 1; |
| } else { |
| DoubleToAscii(value, DTOA_PRECISION, f + 1, |
| Vector<char>(decimal_rep, kV8DtoaBufferCapacity), |
| &sign, &decimal_rep_length, &decimal_point); |
| } |
| DCHECK(decimal_rep_length > 0); |
| DCHECK(decimal_rep_length <= f + 1); |
| |
| int exponent = decimal_point - 1; |
| char* result = |
| CreateExponentialRepresentation(decimal_rep, exponent, negative, f+1); |
| |
| return result; |
| } |
| |
| |
| char* DoubleToPrecisionCString(double value, int p) { |
| const int kMinimalDigits = 1; |
| const int kMaximalDigits = 21; |
| DCHECK(p >= kMinimalDigits && p <= kMaximalDigits); |
| USE(kMinimalDigits); |
| |
| bool negative = false; |
| if (value < 0) { |
| value = -value; |
| negative = true; |
| } |
| |
| // Find a sufficiently precise decimal representation of n. |
| int decimal_point; |
| int sign; |
| // Add one for the terminating null character. |
| const int kV8DtoaBufferCapacity = kMaximalDigits + 1; |
| char decimal_rep[kV8DtoaBufferCapacity]; |
| int decimal_rep_length; |
| |
| DoubleToAscii(value, DTOA_PRECISION, p, |
| Vector<char>(decimal_rep, kV8DtoaBufferCapacity), |
| &sign, &decimal_rep_length, &decimal_point); |
| DCHECK(decimal_rep_length <= p); |
| |
| int exponent = decimal_point - 1; |
| |
| char* result = NULL; |
| |
| if (exponent < -6 || exponent >= p) { |
| result = |
| CreateExponentialRepresentation(decimal_rep, exponent, negative, p); |
| } else { |
| // Use fixed notation. |
| // |
| // Leave room in the result for appending a minus, a period and in |
| // the case where decimal_point is not positive for a zero in |
| // front of the period. |
| unsigned result_size = (decimal_point <= 0) |
| ? -decimal_point + p + 3 |
| : p + 2; |
| SimpleStringBuilder builder(result_size + 1); |
| if (negative) builder.AddCharacter('-'); |
| if (decimal_point <= 0) { |
| builder.AddString("0."); |
| builder.AddPadding('0', -decimal_point); |
| builder.AddString(decimal_rep); |
| builder.AddPadding('0', p - decimal_rep_length); |
| } else { |
| const int m = Min(decimal_rep_length, decimal_point); |
| builder.AddSubstring(decimal_rep, m); |
| builder.AddPadding('0', decimal_point - decimal_rep_length); |
| if (decimal_point < p) { |
| builder.AddCharacter('.'); |
| const int extra = negative ? 2 : 1; |
| if (decimal_rep_length > decimal_point) { |
| const int len = StrLength(decimal_rep + decimal_point); |
| const int n = Min(len, p - (builder.position() - extra)); |
| builder.AddSubstring(decimal_rep + decimal_point, n); |
| } |
| builder.AddPadding('0', extra + (p - builder.position())); |
| } |
| } |
| result = builder.Finalize(); |
| } |
| |
| return result; |
| } |
| |
| char* DoubleToRadixCString(double value, int radix) { |
| DCHECK(radix >= 2 && radix <= 36); |
| DCHECK(std::isfinite(value)); |
| DCHECK_NE(0.0, value); |
| // Character array used for conversion. |
| static const char chars[] = "0123456789abcdefghijklmnopqrstuvwxyz"; |
| |
| // Temporary buffer for the result. We start with the decimal point in the |
| // middle and write to the left for the integer part and to the right for the |
| // fractional part. 1024 characters for the exponent and 52 for the mantissa |
| // either way, with additional space for sign, decimal point and string |
| // termination should be sufficient. |
| static const int kBufferSize = 2200; |
| char buffer[kBufferSize]; |
| int integer_cursor = kBufferSize / 2; |
| int fraction_cursor = integer_cursor; |
| |
| bool negative = value < 0; |
| if (negative) value = -value; |
| |
| // Split the value into an integer part and a fractional part. |
| double integer = std::floor(value); |
| double fraction = value - integer; |
| // We only compute fractional digits up to the input double's precision. |
| double delta = 0.5 * (Double(value).NextDouble() - value); |
| delta = std::max(Double(0.0).NextDouble(), delta); |
| DCHECK_GT(delta, 0.0); |
| if (fraction > delta) { |
| // Insert decimal point. |
| buffer[fraction_cursor++] = '.'; |
| do { |
| // Shift up by one digit. |
| fraction *= radix; |
| delta *= radix; |
| // Write digit. |
| int digit = static_cast<int>(fraction); |
| buffer[fraction_cursor++] = chars[digit]; |
| // Calculate remainder. |
| fraction -= digit; |
| // Round to even. |
| if (fraction > 0.5 || (fraction == 0.5 && (digit & 1))) { |
| if (fraction + delta > 1) { |
| // We need to back trace already written digits in case of carry-over. |
| while (true) { |
| fraction_cursor--; |
| if (fraction_cursor == kBufferSize / 2) { |
| CHECK_EQ('.', buffer[fraction_cursor]); |
| // Carry over to the integer part. |
| integer += 1; |
| break; |
| } |
| char c = buffer[fraction_cursor]; |
| // Reconstruct digit. |
| int digit = c > '9' ? (c - 'a' + 10) : (c - '0'); |
| if (digit + 1 < radix) { |
| buffer[fraction_cursor++] = chars[digit + 1]; |
| break; |
| } |
| } |
| break; |
| } |
| } |
| } while (fraction > delta); |
| } |
| |
| // Compute integer digits. Fill unrepresented digits with zero. |
| while (Double(integer / radix).Exponent() > 0) { |
| integer /= radix; |
| buffer[--integer_cursor] = '0'; |
| } |
| do { |
| double remainder = modulo(integer, radix); |
| buffer[--integer_cursor] = chars[static_cast<int>(remainder)]; |
| integer = (integer - remainder) / radix; |
| } while (integer > 0); |
| |
| // Add sign and terminate string. |
| if (negative) buffer[--integer_cursor] = '-'; |
| buffer[fraction_cursor++] = '\0'; |
| DCHECK_LT(fraction_cursor, kBufferSize); |
| DCHECK_LE(0, integer_cursor); |
| // Allocate new string as return value. |
| char* result = NewArray<char>(fraction_cursor - integer_cursor); |
| memcpy(result, buffer + integer_cursor, fraction_cursor - integer_cursor); |
| return result; |
| } |
| |
| |
| // ES6 18.2.4 parseFloat(string) |
| double StringToDouble(UnicodeCache* unicode_cache, Handle<String> string, |
| int flags, double empty_string_val) { |
| Handle<String> flattened = String::Flatten(string); |
| { |
| DisallowHeapAllocation no_gc; |
| String::FlatContent flat = flattened->GetFlatContent(); |
| DCHECK(flat.IsFlat()); |
| if (flat.IsOneByte()) { |
| return StringToDouble(unicode_cache, flat.ToOneByteVector(), flags, |
| empty_string_val); |
| } else { |
| return StringToDouble(unicode_cache, flat.ToUC16Vector(), flags, |
| empty_string_val); |
| } |
| } |
| } |
| |
| |
| bool IsSpecialIndex(UnicodeCache* unicode_cache, String* string) { |
| // Max length of canonical double: -X.XXXXXXXXXXXXXXXXX-eXXX |
| const int kBufferSize = 24; |
| const int length = string->length(); |
| if (length == 0 || length > kBufferSize) return false; |
| uint16_t buffer[kBufferSize]; |
| String::WriteToFlat(string, buffer, 0, length); |
| // If the first char is not a digit or a '-' or we can't match 'NaN' or |
| // '(-)Infinity', bailout immediately. |
| int offset = 0; |
| if (!IsDecimalDigit(buffer[0])) { |
| if (buffer[0] == '-') { |
| if (length == 1) return false; // Just '-' is bad. |
| if (!IsDecimalDigit(buffer[1])) { |
| if (buffer[1] == 'I' && length == 9) { |
| // Allow matching of '-Infinity' below. |
| } else { |
| return false; |
| } |
| } |
| offset++; |
| } else if (buffer[0] == 'I' && length == 8) { |
| // Allow matching of 'Infinity' below. |
| } else if (buffer[0] == 'N' && length == 3) { |
| // Match NaN. |
| return buffer[1] == 'a' && buffer[2] == 'N'; |
| } else { |
| return false; |
| } |
| } |
| // Expected fast path: key is an integer. |
| static const int kRepresentableIntegerLength = 15; // (-)XXXXXXXXXXXXXXX |
| if (length - offset <= kRepresentableIntegerLength) { |
| const int initial_offset = offset; |
| bool matches = true; |
| for (; offset < length; offset++) { |
| matches &= IsDecimalDigit(buffer[offset]); |
| } |
| if (matches) { |
| // Match 0 and -0. |
| if (buffer[initial_offset] == '0') return initial_offset == length - 1; |
| return true; |
| } |
| } |
| // Slow path: test DoubleToString(StringToDouble(string)) == string. |
| Vector<const uint16_t> vector(buffer, length); |
| double d = StringToDouble(unicode_cache, vector, NO_FLAGS); |
| if (std::isnan(d)) return false; |
| // Compute reverse string. |
| char reverse_buffer[kBufferSize + 1]; // Result will be /0 terminated. |
| Vector<char> reverse_vector(reverse_buffer, arraysize(reverse_buffer)); |
| const char* reverse_string = DoubleToCString(d, reverse_vector); |
| for (int i = 0; i < length; ++i) { |
| if (static_cast<uint16_t>(reverse_string[i]) != buffer[i]) return false; |
| } |
| return true; |
| } |
| } // namespace internal |
| } // namespace v8 |