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Support separator characters.
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Fixes #49
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@floitsch
floitsch committed Sep 9, 2018
1 parent 05a3fea commit 20ecba5
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Showing 3 changed files with 444 additions and 55 deletions.
124 changes: 76 additions & 48 deletions double-conversion/double-conversion.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -551,6 +551,26 @@ static bool IsCharacterDigitForRadix(int c, int radix, char a_character) {
return radix > 10 && c >= a_character && c < a_character + radix - 10;
}

// Returns true, when the iterator is equal to end.
template<class Iterator>
static bool Advance (Iterator* it, char separator, int base, Iterator& end) {
if (separator == StringToDoubleConverter::kNoSeparator) {
++(*it);
return *it == end;
}
if (!isDigit(**it, base)) {
++(*it);
return *it == end;
}
++(*it);
if (*it == end) return true;
if (*it + 1 == end) return false;
if (**it == separator && isDigit(*(*it + 1), base)) {
++(*it);
}
return *it == end;
}

// Checks whether the string in the range start-end is a hex-float string.
// This function assumes that the leading '0x'/'0X' is already consumed.
//
Expand All @@ -561,27 +581,35 @@ static bool IsCharacterDigitForRadix(int c, int radix, char a_character) {
template<class Iterator>
static bool IsHexFloatString(Iterator start,
Iterator end,
char separator,
bool allow_trailing_junk) {
ASSERT(start != end);

Iterator current = start;

while (current != end && isDigit(*current, 16)) ++current;
if (current == end) return false;
bool saw_digit = false;
while (isDigit(*current, 16)) {
saw_digit = true;
if (Advance(&current, separator, 16, end)) return false;
}
if (*current == '.') {
++current;
while (current != end && isDigit(*current, 16)) ++current;
if (current - start == 1) return false; // Only the '.', but no digits.
if (Advance(&current, separator, 16, end)) return false;
while (isDigit(*current, 16)) {
saw_digit = true;
if (Advance(&current, separator, 16, end)) return false;
}
if (!saw_digit) return false; // Only the '.', but no digits.
}
if (current == end) return false;
if (*current != 'p' && *current != 'P') return false;
++current;
if (current == end) return false;
if (*current == '+' || *current == '-') ++current;
if (current == end) return false;
if (Advance(&current, separator, 16, end)) return false;
if (*current == '+' || *current == '-') {
if (Advance(&current, separator, 16, end)) return false;
}
if (!isDigit(*current, 10)) return false;
++current;
while (current != end && isDigit(*current, 10)) ++current;
if (Advance(&current, separator, 16, end)) return true;
while (isDigit(*current, 10)) {
if (Advance(&current, separator, 16, end)) return true;
}
return allow_trailing_junk || !AdvanceToNonspace(&current, end);
}

Expand All @@ -594,38 +622,38 @@ template <int radix_log_2, class Iterator>
static double RadixStringToIeee(Iterator* current,
Iterator end,
bool sign,
char separator,
bool parse_as_hex_float,
bool allow_trailing_junk,
double junk_string_value,
bool read_as_double,
bool* result_is_junk) {
ASSERT(*current != end);
ASSERT(!parse_as_hex_float ||
IsHexFloatString(*current, end, allow_trailing_junk));
IsHexFloatString(*current, end, separator, allow_trailing_junk));

const int kDoubleSize = Double::kSignificandSize;
const int kSingleSize = Single::kSignificandSize;
const int kSignificandSize = read_as_double? kDoubleSize: kSingleSize;

*result_is_junk = true;

// Skip leading 0s.
while (**current == '0') {
++(*current);
if (*current == end) {
*result_is_junk = false;
return SignedZero(sign);
}
}

int64_t number = 0;
int exponent = 0;
const int radix = (1 << radix_log_2);
// Whether we have encountered a '.' and are parsing the decimal digits.
// Only relevant if parse_as_hex_float is true.
bool post_decimal = false;

do {
// Skip leading 0s.
while (**current == '0') {
if (Advance(current, separator, radix, end)) {
*result_is_junk = false;
return SignedZero(sign);
}
}

while (true) {
int digit;
if (IsDecimalDigitForRadix(**current, radix)) {
digit = static_cast<char>(**current) - '0';
Expand All @@ -638,7 +666,8 @@ static double RadixStringToIeee(Iterator* current,
if (post_decimal) exponent -= radix_log_2;
} else if (parse_as_hex_float && **current == '.') {
post_decimal = true;
++(*current);
Advance(current, separator, radix, end);
ASSERT(*current != end);
continue;
} else if (parse_as_hex_float && (**current == 'p' || **current == 'P')) {
break;
Expand Down Expand Up @@ -668,14 +697,15 @@ static double RadixStringToIeee(Iterator* current,

bool zero_tail = true;
for (;;) {
++(*current);
if (Advance(current, separator, radix, end)) break;
if (parse_as_hex_float && **current == '.') {
// Just run over the '.'. We are just trying to see whether there is
// a non-zero digit somewhere.
++(*current);
Advance(current, separator, radix, end);
ASSERT(*current != end);
post_decimal = true;
}
if (*current == end || !isDigit(**current, radix)) break;
if (!isDigit(**current, radix)) break;
zero_tail = zero_tail && **current == '0';
if (!post_decimal) exponent += radix_log_2;
}
Expand Down Expand Up @@ -704,8 +734,8 @@ static double RadixStringToIeee(Iterator* current,
}
break;
}
++(*current);
} while (*current != end);
if (Advance(current, separator, radix, end)) break;
}

ASSERT(number < ((int64_t)1 << kSignificandSize));
ASSERT(static_cast<int64_t>(static_cast<double>(number)) == number);
Expand All @@ -714,18 +744,21 @@ static double RadixStringToIeee(Iterator* current,

if (parse_as_hex_float) {
ASSERT(**current == 'p' || **current == 'P');
++(*current);
Advance(current, separator, radix, end);
ASSERT(*current != end);
bool is_negative = false;
if (**current == '+') {
++(*current);
Advance(current, separator, radix, end);
ASSERT(*current != end);
} else if (**current == '-') {
is_negative = true;
++(*current);
Advance(current, separator, radix, end);
ASSERT(*current != end);
}
int written_exponent = 0;
while (*current != end && IsDecimalDigitForRadix(**current, 10)) {
while (IsDecimalDigitForRadix(**current, 10)) {
written_exponent = 10 * written_exponent + **current - '0';
++(*current);
if (Advance(current, separator, radix, end)) break;
}
if (is_negative) written_exponent = -written_exponent;
exponent += written_exponent;
Expand Down Expand Up @@ -761,7 +794,6 @@ double StringToDoubleConverter::StringToIeee(
const bool allow_spaces_after_sign = (flags_ & ALLOW_SPACES_AFTER_SIGN) != 0;
const bool allow_case_insensibility = (flags_ & ALLOW_CASE_INSENSIBILITY) != 0;


// 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'.
Expand Down Expand Up @@ -849,8 +881,7 @@ double StringToDoubleConverter::StringToIeee(

bool leading_zero = false;
if (*current == '0') {
++current;
if (current == end) {
if (Advance(&current, separator_, 10, end)) {
*processed_characters_count = static_cast<int>(current - input);
return SignedZero(sign);
}
Expand All @@ -863,7 +894,7 @@ double StringToDoubleConverter::StringToIeee(
++current;

bool parse_as_hex_float = (flags_ & ALLOW_HEX_FLOATS) &&
IsHexFloatString(current, end, allow_trailing_junk);
IsHexFloatString(current, end, separator_, allow_trailing_junk);

if (current == end) return junk_string_value_; // "0x"
if (!parse_as_hex_float && !isDigit(*current, 16)) {
Expand All @@ -874,6 +905,7 @@ double StringToDoubleConverter::StringToIeee(
double result = RadixStringToIeee<4>(&current,
end,
sign,
separator_,
parse_as_hex_float,
allow_trailing_junk,
junk_string_value_,
Expand All @@ -888,8 +920,7 @@ double StringToDoubleConverter::StringToIeee(

// Ignore leading zeros in the integer part.
while (*current == '0') {
++current;
if (current == end) {
if (Advance(&current, separator_, 10, end)) {
*processed_characters_count = static_cast<int>(current - input);
return SignedZero(sign);
}
Expand All @@ -910,8 +941,7 @@ double StringToDoubleConverter::StringToIeee(
nonzero_digit_dropped = nonzero_digit_dropped || *current != '0';
}
octal = octal && *current < '8';
++current;
if (current == end) goto parsing_done;
if (Advance(&current, separator_, 10, end)) goto parsing_done;
}

if (significant_digits == 0) {
Expand All @@ -922,8 +952,7 @@ double StringToDoubleConverter::StringToIeee(
if (octal && !allow_trailing_junk) return junk_string_value_;
if (octal) goto parsing_done;

++current;
if (current == end) {
if (Advance(&current, separator_, 10, end)) {
if (significant_digits == 0 && !leading_zero) {
return junk_string_value_;
} else {
Expand All @@ -936,8 +965,7 @@ double StringToDoubleConverter::StringToIeee(
// Integer part consists of 0 or is absent. Significant digits start after
// leading zeros (if any).
while (*current == '0') {
++current;
if (current == end) {
if (Advance(&current, separator_, 10, end)) {
*processed_characters_count = static_cast<int>(current - input);
return SignedZero(sign);
}
Expand All @@ -957,8 +985,7 @@ double StringToDoubleConverter::StringToIeee(
// Ignore insignificant digits in the fractional part.
nonzero_digit_dropped = nonzero_digit_dropped || *current != '0';
}
++current;
if (current == end) goto parsing_done;
if (Advance(&current, separator_, 10, end)) goto parsing_done;
}
}

Expand Down Expand Up @@ -1045,6 +1072,7 @@ double StringToDoubleConverter::StringToIeee(
result = RadixStringToIeee<3>(&start,
buffer + buffer_pos,
sign,
separator_,
false, // Don't parse as hex_float.
allow_trailing_junk,
junk_string_value_,
Expand Down
23 changes: 21 additions & 2 deletions double-conversion/double-conversion.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -399,6 +399,8 @@ class StringToDoubleConverter {
ALLOW_HEX_FLOATS = 128,
};

static const uc16 kNoSeparator = '\0';

// Flags should be a bit-or combination of the possible Flags-enum.
// - NO_FLAGS: no special flags.
// - ALLOW_HEX: recognizes the prefix "0x". Hex numbers may only be integers.
Expand Down Expand Up @@ -459,6 +461,12 @@ class StringToDoubleConverter {
// - they must not have the same first character.
// - they must not start with digits.
//
// If the separator character is not kNoSeparator, then that specific
// character is ignored when in between two valid digits of the significant.
// It is not allowed to appear in the exponent.
// It is not allowed to lead or trail the number.
// It is not allowed to appear twice next to each other.
//
// Examples:
// flags = ALLOW_HEX | ALLOW_TRAILING_JUNK,
// empty_string_value = 0.0,
Expand Down Expand Up @@ -498,16 +506,26 @@ class StringToDoubleConverter {
// StringToDouble("01239E45") -> 1239e45.
// StringToDouble("-infinity") -> NaN // junk_string_value.
// StringToDouble("NaN") -> NaN // junk_string_value.
//
// flags = NO_FLAGS,
// separator = ' ':
// StringToDouble("1 2 3 4") -> 1234.0
// StringToDouble("1 2") -> NaN // junk_string_value
// StringToDouble("1 000 000.0") -> 1000000.0
// StringToDouble("1.000 000") -> 1.0
// StringToDouble("1.0e1 000") -> NaN // junk_string_value
StringToDoubleConverter(int flags,
double empty_string_value,
double junk_string_value,
const char* infinity_symbol,
const char* nan_symbol)
const char* nan_symbol,
uc16 separator = kNoSeparator)
: flags_(flags),
empty_string_value_(empty_string_value),
junk_string_value_(junk_string_value),
infinity_symbol_(infinity_symbol),
nan_symbol_(nan_symbol) {
nan_symbol_(nan_symbol),
separator_(separator) {
}

// Performs the conversion.
Expand Down Expand Up @@ -542,6 +560,7 @@ class StringToDoubleConverter {
const double junk_string_value_;
const char* const infinity_symbol_;
const char* const nan_symbol_;
const uc16 separator_;

template <class Iterator>
double StringToIeee(Iterator start_pointer,
Expand Down
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