| // Copyright 2006-2008 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. |
| |
| #include <stdarg.h> |
| #include <limits.h> |
| |
| #include "v8.h" |
| |
| #include "conversions-inl.h" |
| #include "dtoa.h" |
| #include "factory.h" |
| #include "scanner-base.h" |
| #include "strtod.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| namespace { |
| |
| // C++-style iterator adaptor for StringInputBuffer |
| // (unlike C++ iterators the end-marker has different type). |
| class StringInputBufferIterator { |
| public: |
| class EndMarker {}; |
| |
| explicit StringInputBufferIterator(StringInputBuffer* buffer); |
| |
| int operator*() const; |
| void operator++(); |
| bool operator==(EndMarker const&) const { return end_; } |
| bool operator!=(EndMarker const& m) const { return !end_; } |
| |
| private: |
| StringInputBuffer* const buffer_; |
| int current_; |
| bool end_; |
| }; |
| |
| |
| StringInputBufferIterator::StringInputBufferIterator( |
| StringInputBuffer* buffer) : buffer_(buffer) { |
| ++(*this); |
| } |
| |
| int StringInputBufferIterator::operator*() const { |
| return current_; |
| } |
| |
| |
| void StringInputBufferIterator::operator++() { |
| end_ = !buffer_->has_more(); |
| if (!end_) { |
| current_ = buffer_->GetNext(); |
| } |
| } |
| } |
| |
| |
| template <class Iterator, class EndMark> |
| static 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; |
| } |
| |
| |
| // Maximum number of significant digits in decimal representation. |
| // The longest possible double in decimal representation is |
| // (2^53 - 1) * 2 ^ -1074 that is (2 ^ 53 - 1) * 5 ^ 1074 / 10 ^ 1074 |
| // (768 digits). If we parse a number whose first digits are equal to a |
| // mean of 2 adjacent doubles (that could have up to 769 digits) the result |
| // must be rounded to the bigger one unless the tail consists of zeros, so |
| // we don't need to preserve all the digits. |
| const int kMaxSignificantDigits = 772; |
| |
| |
| static const double JUNK_STRING_VALUE = OS::nan_value(); |
| |
| |
| // Returns true if a nonspace found and false if the end has reached. |
| template <class Iterator, class EndMark> |
| static inline bool AdvanceToNonspace(Iterator* current, EndMark end) { |
| while (*current != end) { |
| if (!ScannerConstants::kIsWhiteSpace.get(**current)) return true; |
| ++*current; |
| } |
| return false; |
| } |
| |
| |
| static bool isDigit(int x, int radix) { |
| return (x >= '0' && x <= '9' && x < '0' + radix) |
| || (radix > 10 && x >= 'a' && x < 'a' + radix - 10) |
| || (radix > 10 && x >= 'A' && x < 'A' + radix - 10); |
| } |
| |
| |
| static double SignedZero(bool negative) { |
| return negative ? -0.0 : 0.0; |
| } |
| |
| |
| // Parsing integers with radix 2, 4, 8, 16, 32. Assumes current != end. |
| template <int radix_log_2, class Iterator, class EndMark> |
| static double InternalStringToIntDouble(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(¤t, end)) { |
| break; |
| } else { |
| return JUNK_STRING_VALUE; |
| } |
| } |
| |
| 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(¤t, end)) { |
| return JUNK_STRING_VALUE; |
| } |
| |
| 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> |
| static double InternalStringToInt(Iterator current, EndMark end, int radix) { |
| const bool allow_trailing_junk = true; |
| const double empty_string_val = JUNK_STRING_VALUE; |
| |
| if (!AdvanceToNonspace(¤t, end)) return empty_string_val; |
| |
| bool negative = false; |
| bool leading_zero = false; |
| |
| if (*current == '+') { |
| // Ignore leading sign; skip following spaces. |
| ++current; |
| if (!AdvanceToNonspace(¤t, end)) return JUNK_STRING_VALUE; |
| } else if (*current == '-') { |
| ++current; |
| if (!AdvanceToNonspace(¤t, end)) return JUNK_STRING_VALUE; |
| 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 JUNK_STRING_VALUE; |
| } 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 JUNK_STRING_VALUE; |
| } else { |
| leading_zero = true; |
| } |
| } |
| } |
| |
| if (radix < 2 || radix > 36) return JUNK_STRING_VALUE; |
| |
| // Skip leading zeros. |
| while (*current == '0') { |
| leading_zero = true; |
| ++current; |
| if (current == end) return SignedZero(negative); |
| } |
| |
| if (!leading_zero && !isDigit(*current, radix)) { |
| return JUNK_STRING_VALUE; |
| } |
| |
| if (IsPowerOf2(radix)) { |
| switch (radix) { |
| case 2: |
| return InternalStringToIntDouble<1>( |
| current, end, negative, allow_trailing_junk); |
| case 4: |
| return InternalStringToIntDouble<2>( |
| current, end, negative, allow_trailing_junk); |
| case 8: |
| return InternalStringToIntDouble<3>( |
| current, end, negative, allow_trailing_junk); |
| |
| case 16: |
| return InternalStringToIntDouble<4>( |
| current, end, negative, allow_trailing_junk); |
| |
| case 32: |
| return InternalStringToIntDouble<5>( |
| 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(¤t, end)) { |
| return JUNK_STRING_VALUE; |
| } |
| |
| 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(¤t, end)) { |
| return JUNK_STRING_VALUE; |
| } |
| |
| 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> |
| static double InternalStringToDouble(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(¤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 fractional_part = false; |
| |
| bool negative = false; |
| |
| if (*current == '+') { |
| // Ignore leading sign. |
| ++current; |
| if (current == end) return JUNK_STRING_VALUE; |
| } else if (*current == '-') { |
| ++current; |
| if (current == end) return JUNK_STRING_VALUE; |
| negative = true; |
| } |
| |
| static const char kInfinitySymbol[] = "Infinity"; |
| if (*current == kInfinitySymbol[0]) { |
| if (!SubStringEquals(¤t, end, kInfinitySymbol)) { |
| return JUNK_STRING_VALUE; |
| } |
| |
| if (!allow_trailing_junk && AdvanceToNonspace(¤t, end)) { |
| return JUNK_STRING_VALUE; |
| } |
| |
| 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 JUNK_STRING_VALUE; // "0x". |
| } |
| |
| return InternalStringToIntDouble<4>(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 JUNK_STRING_VALUE; |
| if (octal) goto parsing_done; |
| |
| ++current; |
| if (current == end) { |
| if (significant_digits == 0 && !leading_zero) { |
| return JUNK_STRING_VALUE; |
| } 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. |
| } |
| } |
| |
| // We don't emit a '.', but adjust the exponent instead. |
| fractional_part = true; |
| |
| // There is a fractional part. |
| 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 JUNK_STRING_VALUE; |
| } |
| |
| // Parse exponential part. |
| if (*current == 'e' || *current == 'E') { |
| if (octal) return JUNK_STRING_VALUE; |
| ++current; |
| if (current == end) { |
| if (allow_trailing_junk) { |
| goto parsing_done; |
| } else { |
| return JUNK_STRING_VALUE; |
| } |
| } |
| char sign = '+'; |
| if (*current == '+' || *current == '-') { |
| sign = static_cast<char>(*current); |
| ++current; |
| if (current == end) { |
| if (allow_trailing_junk) { |
| goto parsing_done; |
| } else { |
| return JUNK_STRING_VALUE; |
| } |
| } |
| } |
| |
| if (current == end || *current < '0' || *current > '9') { |
| if (allow_trailing_junk) { |
| goto parsing_done; |
| } else { |
| return JUNK_STRING_VALUE; |
| } |
| } |
| |
| 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(¤t, end)) { |
| return JUNK_STRING_VALUE; |
| } |
| |
| parsing_done: |
| exponent += insignificant_digits; |
| |
| if (octal) { |
| return InternalStringToIntDouble<3>(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; |
| } |
| |
| |
| double StringToDouble(String* str, int flags, double empty_string_val) { |
| StringShape shape(str); |
| if (shape.IsSequentialAscii()) { |
| const char* begin = SeqAsciiString::cast(str)->GetChars(); |
| const char* end = begin + str->length(); |
| return InternalStringToDouble(begin, end, flags, empty_string_val); |
| } else if (shape.IsSequentialTwoByte()) { |
| const uc16* begin = SeqTwoByteString::cast(str)->GetChars(); |
| const uc16* end = begin + str->length(); |
| return InternalStringToDouble(begin, end, flags, empty_string_val); |
| } else { |
| StringInputBuffer buffer(str); |
| return InternalStringToDouble(StringInputBufferIterator(&buffer), |
| StringInputBufferIterator::EndMarker(), |
| flags, |
| empty_string_val); |
| } |
| } |
| |
| |
| double StringToInt(String* str, int radix) { |
| StringShape shape(str); |
| if (shape.IsSequentialAscii()) { |
| const char* begin = SeqAsciiString::cast(str)->GetChars(); |
| const char* end = begin + str->length(); |
| return InternalStringToInt(begin, end, radix); |
| } else if (shape.IsSequentialTwoByte()) { |
| const uc16* begin = SeqTwoByteString::cast(str)->GetChars(); |
| const uc16* end = begin + str->length(); |
| return InternalStringToInt(begin, end, radix); |
| } else { |
| StringInputBuffer buffer(str); |
| return InternalStringToInt(StringInputBufferIterator(&buffer), |
| StringInputBufferIterator::EndMarker(), |
| radix); |
| } |
| } |
| |
| |
| double StringToDouble(const char* str, int flags, double empty_string_val) { |
| const char* end = str + StrLength(str); |
| return InternalStringToDouble(str, end, flags, empty_string_val); |
| } |
| |
| |
| double StringToDouble(Vector<const char> str, |
| int flags, |
| double empty_string_val) { |
| const char* end = str.start() + str.length(); |
| return InternalStringToDouble(str.start(), end, flags, empty_string_val); |
| } |
| |
| |
| 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: { |
| StringBuilder 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.AddFormatted("%d", 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; |
| ASSERT(f >= 0); |
| ASSERT(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, ARRAY_SIZE(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; |
| StringBuilder 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; |
| StringBuilder 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; |
| StringBuilder 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.AddFormatted("%d", 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. |
| ASSERT(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). |
| ASSERT(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); |
| } |
| ASSERT(decimal_rep_length > 0); |
| ASSERT(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; |
| ASSERT(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); |
| ASSERT(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; |
| StringBuilder 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) { |
| ASSERT(radix >= 2 && radix <= 36); |
| |
| // Character array used for conversion. |
| static const char chars[] = "0123456789abcdefghijklmnopqrstuvwxyz"; |
| |
| // Buffer for the integer part of the result. 1024 chars is enough |
| // for max integer value in radix 2. We need room for a sign too. |
| static const int kBufferSize = 1100; |
| char integer_buffer[kBufferSize]; |
| integer_buffer[kBufferSize - 1] = '\0'; |
| |
| // Buffer for the decimal part of the result. We only generate up |
| // to kBufferSize - 1 chars for the decimal part. |
| char decimal_buffer[kBufferSize]; |
| decimal_buffer[kBufferSize - 1] = '\0'; |
| |
| // Make sure the value is positive. |
| bool is_negative = value < 0.0; |
| if (is_negative) value = -value; |
| |
| // Get the integer part and the decimal part. |
| double integer_part = floor(value); |
| double decimal_part = value - integer_part; |
| |
| // Convert the integer part starting from the back. Always generate |
| // at least one digit. |
| int integer_pos = kBufferSize - 2; |
| do { |
| integer_buffer[integer_pos--] = |
| chars[static_cast<int>(modulo(integer_part, radix))]; |
| integer_part /= radix; |
| } while (integer_part >= 1.0); |
| // Sanity check. |
| ASSERT(integer_pos > 0); |
| // Add sign if needed. |
| if (is_negative) integer_buffer[integer_pos--] = '-'; |
| |
| // Convert the decimal part. Repeatedly multiply by the radix to |
| // generate the next char. Never generate more than kBufferSize - 1 |
| // chars. |
| // |
| // TODO(1093998): We will often generate a full decimal_buffer of |
| // chars because hitting zero will often not happen. The right |
| // solution would be to continue until the string representation can |
| // be read back and yield the original value. To implement this |
| // efficiently, we probably have to modify dtoa. |
| int decimal_pos = 0; |
| while ((decimal_part > 0.0) && (decimal_pos < kBufferSize - 1)) { |
| decimal_part *= radix; |
| decimal_buffer[decimal_pos++] = |
| chars[static_cast<int>(floor(decimal_part))]; |
| decimal_part -= floor(decimal_part); |
| } |
| decimal_buffer[decimal_pos] = '\0'; |
| |
| // Compute the result size. |
| int integer_part_size = kBufferSize - 2 - integer_pos; |
| // Make room for zero termination. |
| unsigned result_size = integer_part_size + decimal_pos; |
| // If the number has a decimal part, leave room for the period. |
| if (decimal_pos > 0) result_size++; |
| // Allocate result and fill in the parts. |
| StringBuilder builder(result_size + 1); |
| builder.AddSubstring(integer_buffer + integer_pos + 1, integer_part_size); |
| if (decimal_pos > 0) builder.AddCharacter('.'); |
| builder.AddSubstring(decimal_buffer, decimal_pos); |
| return builder.Finalize(); |
| } |
| |
| |
| } } // namespace v8::internal |