diff options
Diffstat (limited to 'src/utilstrencodings.cpp')
| -rw-r--r-- | src/utilstrencodings.cpp | 131 |
1 files changed, 126 insertions, 5 deletions
diff --git a/src/utilstrencodings.cpp b/src/utilstrencodings.cpp index 7d1de7d6a8..1f7a2cae2c 100644 --- a/src/utilstrencodings.cpp +++ b/src/utilstrencodings.cpp @@ -464,11 +464,12 @@ bool ParseDouble(const std::string& str, double *out) return false; if (str.size() >= 2 && str[0] == '0' && str[1] == 'x') // No hexadecimal floats allowed return false; - char *endp = NULL; - errno = 0; // strtod will not set errno if valid - double n = strtod(str.c_str(), &endp); - if(out) *out = n; - return endp && *endp == 0 && !errno; + std::istringstream text(str); + text.imbue(std::locale::classic()); + double result; + text >> result; + if(out) *out = result; + return text.eof() && !text.fail(); } std::string FormatParagraph(const std::string& in, size_t width, size_t indent) @@ -538,3 +539,123 @@ int atoi(const std::string& str) { return atoi(str.c_str()); } + +/** Upper bound for mantissa. + * 10^18-1 is the largest arbitrary decimal that will fit in a signed 64-bit integer. + * Larger integers cannot consist of arbitrary combinations of 0-9: + * + * 999999999999999999 1^18-1 + * 9223372036854775807 (1<<63)-1 (max int64_t) + * 9999999999999999999 1^19-1 (would overflow) + */ +static const int64_t UPPER_BOUND = 1000000000000000000LL - 1LL; + +/** Helper function for ParseFixedPoint */ +static inline bool ProcessMantissaDigit(char ch, int64_t &mantissa, int &mantissa_tzeros) +{ + if(ch == '0') + ++mantissa_tzeros; + else { + for (int i=0; i<=mantissa_tzeros; ++i) { + if (mantissa > (UPPER_BOUND / 10LL)) + return false; /* overflow */ + mantissa *= 10; + } + mantissa += ch - '0'; + mantissa_tzeros = 0; + } + return true; +} + +bool ParseFixedPoint(const std::string &val, int decimals, int64_t *amount_out) +{ + int64_t mantissa = 0; + int64_t exponent = 0; + int mantissa_tzeros = 0; + bool mantissa_sign = false; + bool exponent_sign = false; + int ptr = 0; + int end = val.size(); + int point_ofs = 0; + + if (ptr < end && val[ptr] == '-') { + mantissa_sign = true; + ++ptr; + } + if (ptr < end) + { + if (val[ptr] == '0') { + /* pass single 0 */ + ++ptr; + } else if (val[ptr] >= '1' && val[ptr] <= '9') { + while (ptr < end && val[ptr] >= '0' && val[ptr] <= '9') { + if (!ProcessMantissaDigit(val[ptr], mantissa, mantissa_tzeros)) + return false; /* overflow */ + ++ptr; + } + } else return false; /* missing expected digit */ + } else return false; /* empty string or loose '-' */ + if (ptr < end && val[ptr] == '.') + { + ++ptr; + if (ptr < end && val[ptr] >= '0' && val[ptr] <= '9') + { + while (ptr < end && val[ptr] >= '0' && val[ptr] <= '9') { + if (!ProcessMantissaDigit(val[ptr], mantissa, mantissa_tzeros)) + return false; /* overflow */ + ++ptr; + ++point_ofs; + } + } else return false; /* missing expected digit */ + } + if (ptr < end && (val[ptr] == 'e' || val[ptr] == 'E')) + { + ++ptr; + if (ptr < end && val[ptr] == '+') + ++ptr; + else if (ptr < end && val[ptr] == '-') { + exponent_sign = true; + ++ptr; + } + if (ptr < end && val[ptr] >= '0' && val[ptr] <= '9') { + while (ptr < end && val[ptr] >= '0' && val[ptr] <= '9') { + if (exponent > (UPPER_BOUND / 10LL)) + return false; /* overflow */ + exponent = exponent * 10 + val[ptr] - '0'; + ++ptr; + } + } else return false; /* missing expected digit */ + } + if (ptr != end) + return false; /* trailing garbage */ + + /* finalize exponent */ + if (exponent_sign) + exponent = -exponent; + exponent = exponent - point_ofs + mantissa_tzeros; + + /* finalize mantissa */ + if (mantissa_sign) + mantissa = -mantissa; + + /* convert to one 64-bit fixed-point value */ + exponent += decimals; + if (exponent < 0) + return false; /* cannot represent values smaller than 10^-decimals */ + if (exponent >= 18) + return false; /* cannot represent values larger than or equal to 10^(18-decimals) */ + + for (int i=0; i < exponent; ++i) { + if (mantissa > (UPPER_BOUND / 10LL) || mantissa < -(UPPER_BOUND / 10LL)) + return false; /* overflow */ + mantissa *= 10; + } + if (mantissa > UPPER_BOUND || mantissa < -UPPER_BOUND) + return false; /* overflow */ + + if (amount_out) + *amount_out = mantissa; + + return true; +} + |