// 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 "v8.h"
#include "conversions-inl.h"
#include "factory.h"
#include "scanner.h"
namespace v8 {
namespace internal {
int HexValue(uc32 c) {
if ('0' <= c && c <= '9')
return c - '0';
if ('a' <= c && c <= 'f')
return c - 'a' + 10;
if ('A' <= c && c <= 'F')
return c - 'A' + 10;
return -1;
}
// Provide a common interface to getting a character at a certain
// index from a char* or a String object.
static inline int GetChar(const char* str, int index) {
ASSERT(index >= 0 && index < StrLength(str));
return str[index];
}
static inline int GetChar(String* str, int index) {
return str->Get(index);
}
static inline int GetLength(const char* str) {
return StrLength(str);
}
static inline int GetLength(String* str) {
return str->length();
}
static inline const char* GetCString(const char* str, int index) {
return str + index;
}
static inline const char* GetCString(String* str, int index) {
int length = str->length();
char* result = NewArray<char>(length + 1);
for (int i = index; i < length; i++) {
uc16 c = str->Get(i);
if (c <= 127) {
result[i - index] = static_cast<char>(c);
} else {
result[i - index] = 127; // Force number parsing to fail.
}
}
result[length - index] = '\0';
return result;
}
static inline void ReleaseCString(const char* original, const char* str) {
}
static inline void ReleaseCString(String* original, const char* str) {
DeleteArray(const_cast<char *>(str));
}
static inline bool IsSpace(const char* str, int index) {
ASSERT(index >= 0 && index < StrLength(str));
return Scanner::kIsWhiteSpace.get(str[index]);
}
static inline bool IsSpace(String* str, int index) {
return Scanner::kIsWhiteSpace.get(str->Get(index));
}
static inline bool SubStringEquals(const char* str,
int index,
const char* other) {
return strncmp(str + index, other, strlen(other)) != 0;
}
static inline bool SubStringEquals(String* str, int index, const char* other) {
HandleScope scope;
int str_length = str->length();
int other_length = StrLength(other);
int end = index + other_length < str_length ?
index + other_length :
str_length;
Handle<String> substring =
Factory::NewSubString(Handle<String>(str), index, end);
return substring->IsEqualTo(Vector<const char>(other, other_length));
}
// Check if a string should be parsed as an octal number. The string
// can be either a char* or a String*.
template<class S>
static bool ShouldParseOctal(S* s, int i) {
int index = i;
int len = GetLength(s);
if (index < len && GetChar(s, index) != '0') return false;
// If the first real character (following '0') is not an octal
// digit, bail out early. This also takes care of numbers of the
// forms 0.xxx and 0exxx by not allowing the first 0 to be
// interpreted as an octal.
index++;
if (index < len) {
int d = GetChar(s, index) - '0';
if (d < 0 || d > 7) return false;
} else {
return false;
}
// Traverse all digits (including the first). If there is an octal
// prefix which is not a part of a longer decimal prefix, we return
// true. Otherwise, false is returned.
while (index < len) {
int d = GetChar(s, index++) - '0';
if (d == 8 || d == 9) return false;
if (d < 0 || d > 7) return true;
}
return true;
}
extern "C" double gay_strtod(const char* s00, const char** se);
// Parse an int from a string starting a given index and in a given
// radix. The string can be either a char* or a String*.
template <class S>
static int InternalStringToInt(S* s, int i, int radix, double* value) {
int len = GetLength(s);
// Setup limits for computing the value.
ASSERT(2 <= radix && radix <= 36);
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;
int j;
for (j = i; j < len;) {
// Parse the longest part of the string starting at index j
// possible while keeping the multiplier, and thus the part
// itself, within 32 bits.
uint32_t part = 0, multiplier = 1;
int k;
for (k = j; k < len; k++) {
int c = GetChar(s, k);
if (c >= '0' && c < lim_0) {
c = c - '0';
} else if (c >= 'a' && c < lim_a) {
c = c - 'a' + 10;
} else if (c >= 'A' && c < lim_A) {
c = c - 'A' + 10;
} else {
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.
static const uint32_t kMaximumMultiplier = 0xffffffffU / 36;
uint32_t m = multiplier * radix;
if (m > kMaximumMultiplier) break;
part = part * radix + c;
multiplier = m;
ASSERT(multiplier > part);
}
// Compute the number of part digits. If no digits were parsed;
// we're done parsing the entire string.
int digits = k - j;
if (digits == 0) break;
// Update the value and skip the part in the string.
ASSERT(multiplier ==
pow(static_cast<double>(radix), static_cast<double>(digits)));
v = v * multiplier + part;
j = k;
}
// If the resulting value is larger than 2^53 the value does not fit
// in the mantissa of the double and there is a loss of precision.
// When the value is larger than 2^53 the rounding depends on the
// code generation. If the code generator spills the double value
// it uses 64 bits and if it does not it uses 80 bits.
//
// If there is a potential for overflow we resort to strtod for
// radix 10 numbers to get higher precision. For numbers in another
// radix we live with the loss of precision.
static const double kPreciseConversionLimit = 9007199254740992.0;
if (radix == 10 && v > kPreciseConversionLimit) {
const char* cstr = GetCString(s, i);
const char* end;
v = gay_strtod(cstr, &end);
ReleaseCString(s, cstr);
}
*value = v;
return j;
}
int StringToInt(String* str, int index, int radix, double* value) {
return InternalStringToInt(str, index, radix, value);
}
int StringToInt(const char* str, int index, int radix, double* value) {
return InternalStringToInt(const_cast<char*>(str), index, radix, value);
}
static const double JUNK_STRING_VALUE = OS::nan_value();
// Convert a string to a double value. The string can be either a
// char* or a String*.
template<class S>
static double InternalStringToDouble(S* str,
int flags,
double empty_string_val) {
double result = 0.0;
int index = 0;
int len = GetLength(str);
// Skip leading spaces.
while ((index < len) && IsSpace(str, index)) index++;
// Is the string empty?
if (index >= len) return empty_string_val;
// Get the first character.
uint16_t first = GetChar(str, index);
// Numbers can only start with '-', '+', '.', 'I' (Infinity), or a digit.
if (first != '-' && first != '+' && first != '.' && first != 'I' &&
(first > '9' || first < '0')) {
return JUNK_STRING_VALUE;
}
// Compute sign of result based on first character.
int sign = 1;
if (first == '-') {
sign = -1;
index++;
// String only containing a '-' are junk chars.
if (index == len) return JUNK_STRING_VALUE;
}
// do we have a hex number?
// (since the string is 0-terminated, it's ok to look one char beyond the end)
if ((flags & ALLOW_HEX) != 0 &&
(index + 1) < len &&
GetChar(str, index) == '0' &&
(GetChar(str, index + 1) == 'x' || GetChar(str, index + 1) == 'X')) {
index += 2;
index = StringToInt(str, index, 16, &result);
} else if ((flags & ALLOW_OCTALS) != 0 && ShouldParseOctal(str, index)) {
// NOTE: We optimistically try to parse the number as an octal (if
// we're allowed to), even though this is not as dictated by
// ECMA-262. The reason for doing this is compatibility with IE and
// Firefox.
index = StringToInt(str, index, 8, &result);
} else {
const char* cstr = GetCString(str, index);
const char* end;
// Optimistically parse the number and then, if that fails,
// check if it might have been {+,-,}Infinity.
result = gay_strtod(cstr, &end);
ReleaseCString(str, cstr);
if (result != 0.0 || end != cstr) {
// It appears that strtod worked
index += static_cast<int>(end - cstr);
} else {
// Check for {+,-,}Infinity
bool is_negative = (GetChar(str, index) == '-');
if (GetChar(str, index) == '+' || GetChar(str, index) == '-')
index++;
if (!SubStringEquals(str, index, "Infinity"))
return JUNK_STRING_VALUE;
result = is_negative ? -V8_INFINITY : V8_INFINITY;
index += 8;
}
}
if ((flags & ALLOW_TRAILING_JUNK) == 0) {
// skip trailing spaces
while ((index < len) && IsSpace(str, index)) index++;
// string ending with junk?
if (index < len) return JUNK_STRING_VALUE;
}
return sign * result;
}
double StringToDouble(String* str, int flags, double empty_string_val) {
return InternalStringToDouble(str, flags, empty_string_val);
}
double StringToDouble(const char* str, int flags, double empty_string_val) {
return InternalStringToDouble(str, flags, empty_string_val);
}
extern "C" char* dtoa(double d, int mode, int ndigits,
int* decpt, int* sign, char** rve);
extern "C" void freedtoa(char* s);
const char* DoubleToCString(double v, Vector<char> buffer) {
StringBuilder builder(buffer.start(), buffer.length());
switch (fpclassify(v)) {
case FP_NAN:
builder.AddString("NaN");
break;
case FP_INFINITE:
if (v < 0.0) {
builder.AddString("-Infinity");
} else {
builder.AddString("Infinity");
}
break;
case FP_ZERO:
builder.AddCharacter('0');
break;
default: {
int decimal_point;
int sign;
char* decimal_rep = dtoa(v, 0, 0, &decimal_point, &sign, NULL);
int length = StrLength(decimal_rep);
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);
}
freedtoa(decimal_rep);
}
}
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) {
ASSERT(f >= 0);
bool negative = false;
double abs_value = value;
if (value < 0) {
abs_value = -value;
negative = true;
}
if (abs_value >= 1e21) {
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;
char* decimal_rep = dtoa(abs_value, 3, f, &decimal_point, &sign, NULL);
int decimal_rep_length = StrLength(decimal_rep);
// 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();
freedtoa(decimal_rep);
// 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) {
// f might be -1 to signal that f was undefined in JavaScript.
ASSERT(f >= -1 && f <= 20);
bool negative = false;
if (value < 0) {
value = -value;
negative = true;
}
// Find a sufficiently precise decimal representation of n.
int decimal_point;
int sign;
char* decimal_rep = NULL;
if (f == -1) {
decimal_rep = dtoa(value, 0, 0, &decimal_point, &sign, NULL);
f = StrLength(decimal_rep) - 1;
} else {
decimal_rep = dtoa(value, 2, f + 1, &decimal_point, &sign, NULL);
}
int decimal_rep_length = StrLength(decimal_rep);
ASSERT(decimal_rep_length > 0);
ASSERT(decimal_rep_length <= f + 1);
USE(decimal_rep_length);
int exponent = decimal_point - 1;
char* result =
CreateExponentialRepresentation(decimal_rep, exponent, negative, f+1);
freedtoa(decimal_rep);
return result;
}
char* DoubleToPrecisionCString(double value, int p) {
ASSERT(p >= 1 && p <= 21);
bool negative = false;
if (value < 0) {
value = -value;
negative = true;
}
// Find a sufficiently precise decimal representation of n.
int decimal_point;
int sign;
char* decimal_rep = dtoa(value, 2, p, &decimal_point, &sign, NULL);
int decimal_rep_length = StrLength(decimal_rep);
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();
}
freedtoa(decimal_rep);
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