strencodings.cpp

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#include <util/strencodings.h>
#include <util/string.h>
 
#include <tinyformat.h>
 
#include <crypto/hex_base.h>
#include <span.h>
 
#include <array>
#include <cstdlib>
#include <cstring>
#include <optional>
 
static const std::string CHARS_ALPHA_NUM =
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 
static const std::string SAFE_CHARS[] = {
    // SAFE_CHARS_DEFAULT
    CHARS_ALPHA_NUM + " .,;-_/:?@()",
    // SAFE_CHARS_UA_COMMENT
    CHARS_ALPHA_NUM + " .,;-_?@",
    // SAFE_CHARS_FILENAME
    CHARS_ALPHA_NUM + ".-_",
    // SAFE_CHARS_URI
    CHARS_ALPHA_NUM + "!*'();:@&=+$,/?#[]-_.~%",
};
 
std::string SanitizeString(std::string_view str, int rule) {
    std::string result;
    for (char c : str) {
        if (SAFE_CHARS[rule].find(c) != std::string::npos) {
            result.push_back(c);
        }
    }
    return result;
}
 
bool IsHex(std::string_view str) {
    for (char c : str) {
        if (HexDigit(c) < 0) {
            return false;
        }
    }
    return (str.size() > 0) && (str.size() % 2 == 0);
}
 
bool IsHexNumber(std::string_view str) {
    if (str.substr(0, 2) == "0x") {
        str.remove_prefix(2);
    }
    for (char c : str) {
        if (HexDigit(c) < 0) {
            return false;
        }
    }
    // Return false for empty string or "0x".
    return str.size() > 0;
}
 
template <typename Byte>
std::optional<std::vector<Byte>> TryParseHex(std::string_view str) {
    std::vector<Byte> vch;
    auto it = str.begin();
    while (it != str.end()) {
        if (IsSpace(*it)) {
            ++it;
            continue;
        }
        auto c1 = HexDigit(*(it++));
        if (it == str.end()) {
            return std::nullopt;
        }
        auto c2 = HexDigit(*(it++));
        if (c1 < 0 || c2 < 0) {
            return std::nullopt;
        }
        vch.push_back(Byte(c1 << 4) | Byte(c2));
    }
    return vch;
}
template std::vector<std::byte> ParseHex(std::string_view);
template std::vector<uint8_t> ParseHex(std::string_view);
 
bool SplitHostPort(std::string_view in, uint16_t &portOut,
                   std::string &hostOut) {
    bool valid = false;
    size_t colon = in.find_last_of(':');
    // if a : is found, and it either follows a [...], or no other : is in the
    // string, treat it as port separator
    bool fHaveColon = colon != in.npos;
    // if there is a colon, and in[0]=='[', colon is not 0, so in[colon-1] is
    // safe
    bool fBracketed = fHaveColon && (in[0] == '[' && in[colon - 1] == ']');
    bool fMultiColon =
        fHaveColon && (in.find_last_of(':', colon - 1) != in.npos);
    if (fHaveColon && (colon == 0 || fBracketed || !fMultiColon)) {
        uint16_t n;
        if (ParseUInt16(in.substr(colon + 1), &n)) {
            in = in.substr(0, colon);
            portOut = n;
            valid = (portOut != 0);
        }
    } else {
        valid = true;
    }
    if (in.size() > 0 && in[0] == '[' && in[in.size() - 1] == ']') {
        hostOut = in.substr(1, in.size() - 2);
    } else {
        hostOut = in;
    }
 
    return valid;
}
 
std::string EncodeBase64(Span<const uint8_t> input) {
    static const char *pbase64 =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
    std::string str;
    str.reserve(((input.size() + 2) / 3) * 4);
    ConvertBits<8, 6, true>([&](int v) { str += pbase64[v]; }, input.begin(),
                            input.end());
    while (str.size() % 4) {
        str += '=';
    }
    return str;
}
 
std::optional<std::vector<uint8_t>> DecodeBase64(std::string_view str) {
    static const int8_t decode64_table[256] = {
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57,
        58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0,  1,  2,  3,  4,  5,  6,
        7,  8,  9,  10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
        25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
        37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1};
 
    if (str.size() % 4 != 0) {
        return {};
    }
    /* One or two = characters at the end are permitted. */
    if (str.size() >= 1 && str.back() == '=') {
        str.remove_suffix(1);
    }
    if (str.size() >= 1 && str.back() == '=') {
        str.remove_suffix(1);
    }
 
    std::vector<uint8_t> ret;
    ret.reserve((str.size() * 3) / 4);
    bool valid = ConvertBits<6, 8, false>(
        [&](uint8_t c) { ret.push_back(c); }, str.begin(), str.end(),
        [](char c) { return decode64_table[uint8_t(c)]; });
    if (!valid) {
        return {};
    }
 
    return ret;
}
 
std::string EncodeBase32(Span<const uint8_t> input, bool pad) {
    static const char *pbase32 = "abcdefghijklmnopqrstuvwxyz234567";
 
    std::string str;
    str.reserve(((input.size() + 4) / 5) * 8);
    ConvertBits<8, 5, true>([&](int v) { str += pbase32[v]; }, input.begin(),
                            input.end());
    if (pad) {
        while (str.size() % 8) {
            str += '=';
        }
    }
    return str;
}
 
std::string EncodeBase32(std::string_view str, bool pad) {
    return EncodeBase32(MakeUCharSpan(str), pad);
}
 
std::optional<std::vector<uint8_t>> DecodeBase32(std::string_view str) {
    static const int8_t decode32_table[256] = {
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29,
        30, 31, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0,  1,  2,  3,  4,  5,  6,
        7,  8,  9,  10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
        25, -1, -1, -1, -1, -1, -1, 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10,
        11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1};
 
    if (str.size() % 8 != 0) {
        return {};
    }
    /* 1, 3, 4, or 6 padding '=' suffix characters are permitted. */
    if (str.size() >= 1 && str.back() == '=') {
        str.remove_suffix(1);
    }
    if (str.size() >= 2 && str.substr(str.size() - 2) == "==") {
        str.remove_suffix(2);
    }
    if (str.size() >= 1 && str.back() == '=') {
        str.remove_suffix(1);
    }
    if (str.size() >= 2 && str.substr(str.size() - 2) == "==") {
        str.remove_suffix(2);
    }
 
    std::vector<uint8_t> ret;
    ret.reserve((str.size() * 5) / 8);
    bool valid = ConvertBits<5, 8, false>(
        [&](uint8_t c) { ret.push_back(c); }, str.begin(), str.end(),
        [](char c) { return decode32_table[uint8_t(c)]; });
 
    if (!valid) {
        return {};
    }
 
    return ret;
}
 
namespace {
template <typename T> bool ParseIntegral(std::string_view str, T *out) {
    static_assert(std::is_integral<T>::value);
    // Replicate the exact behavior of strtol/strtoll/strtoul/strtoull when
    // handling leading +/- for backwards compatibility.
    if (str.length() >= 2 && str[0] == '+' && str[1] == '-') {
        return false;
    }
    const std::optional<T> opt_int =
        ToIntegral<T>((!str.empty() && str[0] == '+') ? str.substr(1) : str);
    if (!opt_int) {
        return false;
    }
    if (out != nullptr) {
        *out = *opt_int;
    }
    return true;
}
}; // namespace
 
bool ParseInt32(std::string_view str, int32_t *out) {
    return ParseIntegral<int32_t>(str, out);
}
 
bool ParseInt64(std::string_view str, int64_t *out) {
    return ParseIntegral<int64_t>(str, out);
}
 
bool ParseUInt8(std::string_view str, uint8_t *out) {
    return ParseIntegral<uint8_t>(str, out);
}
 
bool ParseUInt16(std::string_view str, uint16_t *out) {
    return ParseIntegral<uint16_t>(str, out);
}
 
bool ParseUInt32(std::string_view str, uint32_t *out) {
    return ParseIntegral<uint32_t>(str, out);
}
 
bool ParseUInt64(std::string_view str, uint64_t *out) {
    return ParseIntegral<uint64_t>(str, out);
}
 
std::string FormatParagraph(std::string_view in, size_t width, size_t indent) {
    std::stringstream out;
    size_t ptr = 0;
    size_t indented = 0;
    while (ptr < in.size()) {
        size_t lineend = in.find_first_of('\n', ptr);
        if (lineend == std::string::npos) {
            lineend = in.size();
        }
        const size_t linelen = lineend - ptr;
        const size_t rem_width = width - indented;
        if (linelen <= rem_width) {
            out << in.substr(ptr, linelen + 1);
            ptr = lineend + 1;
            indented = 0;
        } else {
            size_t finalspace = in.find_last_of(" \n", ptr + rem_width);
            if (finalspace == std::string::npos || finalspace < ptr) {
                // No place to break; just include the entire word and move on
                finalspace = in.find_first_of("\n ", ptr);
                if (finalspace == std::string::npos) {
                    // End of the string, just add it and break
                    out << in.substr(ptr);
                    break;
                }
            }
            out << in.substr(ptr, finalspace - ptr) << "\n";
            if (in[finalspace] == '\n') {
                indented = 0;
            } else if (indent) {
                out << std::string(indent, ' ');
                indented = indent;
            }
            ptr = finalspace + 1;
        }
    }
    return out.str();
}
 
static const int64_t UPPER_BOUND = 1000000000000000000LL - 1LL;
 
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) {
            // overflow
            if (mantissa > (UPPER_BOUND / 10LL)) {
                return false;
            }
            mantissa *= 10;
        }
        mantissa += ch - '0';
        mantissa_tzeros = 0;
    }
    return true;
}
 
bool ParseFixedPoint(std::string_view 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 && IsDigit(val[ptr])) {
                if (!ProcessMantissaDigit(val[ptr], mantissa,
                                          mantissa_tzeros)) {
                    // overflow
                    return false;
                }
                ++ptr;
            }
        } else {
            // missing expected digit
            return false;
        }
    } else {
        // empty string or loose '-'
        return false;
    }
    if (ptr < end && val[ptr] == '.') {
        ++ptr;
        if (ptr < end && IsDigit(val[ptr])) {
            while (ptr < end && IsDigit(val[ptr])) {
                if (!ProcessMantissaDigit(val[ptr], mantissa,
                                          mantissa_tzeros)) {
                    // overflow
                    return false;
                }
                ++ptr;
                ++point_ofs;
            }
        } else {
            // missing expected digit
            return false;
        }
    }
    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 && IsDigit(val[ptr])) {
            while (ptr < end && IsDigit(val[ptr])) {
                if (exponent > (UPPER_BOUND / 10LL)) {
                    // overflow
                    return false;
                }
                exponent = exponent * 10 + val[ptr] - '0';
                ++ptr;
            }
        } else {
            // missing expected digit
            return false;
        }
    }
    if (ptr != end) {
        // trailing garbage
        return false;
    }
    // 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) {
        // cannot represent values smaller than 10^-decimals
        return false;
    }
    if (exponent >= 18) {
        // cannot represent values larger than or equal to 10^(18-decimals)
        return false;
    }
 
    for (int i = 0; i < exponent; ++i) {
        if (mantissa > (UPPER_BOUND / 10LL) ||
            mantissa < -(UPPER_BOUND / 10LL)) {
            // overflow
            return false;
        }
        mantissa *= 10;
    }
    if (mantissa > UPPER_BOUND || mantissa < -UPPER_BOUND) {
        // overflow
        return false;
    }
 
    if (amount_out) {
        *amount_out = mantissa;
    }
 
    return true;
}
 
std::string ToLower(std::string_view str) {
    std::string r;
    for (auto ch : str) {
        r += ToLower(ch);
    }
    return r;
}
 
std::string ToUpper(std::string_view str) {
    std::string r;
    for (auto ch : str) {
        r += ToUpper(ch);
    }
    return r;
}
 
std::string Capitalize(std::string str) {
    if (str.empty()) {
        return str;
    }
    str[0] = ToUpper(str.front());
    return str;
}