// 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. #include #include #include #include "conversions-inl.h" #include "dtoa.h" #include "strtod.h" #include "utils.h" namespace v8 { namespace internal { double StringToDouble(UnicodeCache* unicode_cache, const char* str, int flags, double empty_string_val) { const char* end = str + StrLength(str); return InternalStringToDouble(unicode_cache, str, end, flags, empty_string_val); } double StringToDouble(UnicodeCache* unicode_cache, Vector str, int flags, double empty_string_val) { const char* end = str.start() + str.length(); return InternalStringToDouble(unicode_cache, str.start(), end, flags, empty_string_val); } double StringToDouble(UnicodeCache* unicode_cache, Vector 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); } const char* DoubleToCString(double v, Vector 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(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 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 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(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. 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(decimal_rep, kV8DtoaBufferCapacity), &sign, &decimal_rep_length, &decimal_point); f = decimal_rep_length - 1; } else { DoubleToAscii(value, DTOA_PRECISION, f + 1, Vector(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(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; 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) { 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(fmod(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(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. 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); return builder.Finalize(); } } } // namespace v8::internal