Extract string->double and double->string conversions for use in the preparser.

src/conversions.cc

Index: src/conversions.cc
diff --git a/src/conversions.cc b/src/conversions.cc
index 353b6810f5ba8e474223966eadbe7bf7d31d8d74..232eda08c933cf7bf6418e58edf1a0c2e66ee2c2 100644
--- a/src/conversions.cc
+++ b/src/conversions.cc
@@ -28,693 +28,15 @@
 #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"
+#include "utils.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(UnicodeCache* unicode_cache,
-                                     Iterator* current,
-                                     EndMark end) {
-  while (*current != end) {
-    if (!unicode_cache->IsWhiteSpace(**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(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, &current, 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(unicode_cache, &current, 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(UnicodeCache* unicode_cache,
-                                  Iterator current,
-                                  EndMark end,
-                                  int radix) {
-  const bool allow_trailing_junk = true;
-  const double empty_string_val = JUNK_STRING_VALUE;
-
-  if (!AdvanceToNonspace(unicode_cache, &current, 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 JUNK_STRING_VALUE;
-    }
-  } else if (*current == '-') {
-    ++current;
-    if (current == 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>(
-            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, &current, 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(unicode_cache, &current, 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(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, &current, 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(&current, end, kInfinitySymbol)) {
-      return JUNK_STRING_VALUE;
-    }
-
-    if (!allow_trailing_junk &&
-        AdvanceToNonspace(unicode_cache, &current, 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>(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 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(unicode_cache, &current, end)) {
-    return JUNK_STRING_VALUE;
-  }
-
-  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;
-}
-
-
-double StringToDouble(UnicodeCache* unicode_cache,
-                      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(unicode_cache, 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(unicode_cache, begin, end, flags,
-                                  empty_string_val);
-  } else {
-    StringInputBuffer buffer(str);
-    return InternalStringToDouble(unicode_cache,
-                                  StringInputBufferIterator(&buffer),
-                                  StringInputBufferIterator::EndMarker(),
-                                  flags,
-                                  empty_string_val);
-  }
-}
-
-
-double StringToInt(UnicodeCache* unicode_cache,
-                   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(unicode_cache, begin, end, radix);
-  } else if (shape.IsSequentialTwoByte()) {
-    const uc16* begin = SeqTwoByteString::cast(str)->GetChars();
-    const uc16* end = begin + str->length();
-    return InternalStringToInt(unicode_cache, begin, end, radix);
-  } else {
-    StringInputBuffer buffer(str);
-    return InternalStringToInt(unicode_cache,
-                               StringInputBufferIterator(&buffer),
-                               StringInputBufferIterator::EndMarker(),
-                               radix);
-  }
-}
 
 
 double StringToDouble(UnicodeCache* unicode_cache,
@@ -750,7 +72,7 @@ const char* DoubleToCString(double v, Vector<char> buffer) {
     case FP_INFINITE: return (v < 0.0 ? "-Infinity" : "Infinity");
     case FP_ZERO: return "0";
     default: {
-      StringBuilder builder(buffer.start(), buffer.length());
+      SimpleStringBuilder builder(buffer.start(), buffer.length());
       int decimal_point;
       int sign;
       const int kV8DtoaBufferCapacity = kBase10MaximalLength + 1;
@@ -791,7 +113,7 @@ const char* DoubleToCString(double v, Vector<char> buffer) {
         builder.AddCharacter((decimal_point >= 0) ? '+' : '-');
         int exponent = decimal_point - 1;
         if (exponent < 0) exponent = -exponent;
-        builder.AddFormatted("%d", exponent);
+        builder.AddDecimalInteger(exponent);
       }
     return builder.Finalize();
     }
@@ -869,7 +191,7 @@ char* DoubleToFixedCString(double value, int f) {
 
   unsigned rep_length =
       zero_prefix_length + decimal_rep_length + zero_postfix_length;
-  StringBuilder rep_builder(rep_length + 1);
+  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);
@@ -878,7 +200,7 @@ char* DoubleToFixedCString(double value, int f) {
   // 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);
+  SimpleStringBuilder builder(result_size + 1);
   if (negative) builder.AddCharacter('-');
   builder.AddSubstring(rep, decimal_point);
   if (f > 0) {
@@ -904,7 +226,7 @@ static char* CreateExponentialRepresentation(char* decimal_rep,
   // 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);
+  SimpleStringBuilder builder(result_size + 1);
 
   if (negative) builder.AddCharacter('-');
   builder.AddCharacter(decimal_rep[0]);
@@ -917,7 +239,7 @@ static char* CreateExponentialRepresentation(char* decimal_rep,
 
   builder.AddCharacter('e');
   builder.AddCharacter(negative_exponent ? '-' : '+');
-  builder.AddFormatted("%d", exponent);
+  builder.AddDecimalInteger(exponent);
   return builder.Finalize();
 }
 
@@ -1009,7 +331,7 @@ char* DoubleToPrecisionCString(double value, int p) {
     unsigned result_size = (decimal_point <= 0)
         ? -decimal_point + p + 3
         : p + 2;
-    StringBuilder builder(result_size + 1);
+    SimpleStringBuilder builder(result_size + 1);
     if (negative) builder.AddCharacter('-');
     if (decimal_point <= 0) {
       builder.AddString("0.");
@@ -1101,7 +423,7 @@ char* DoubleToRadixCString(double value, int radix) {
   // 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);
+  SimpleStringBuilder 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);