strencodings.h

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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.
 
#ifndef BITCOIN_UTIL_STRENCODINGS_H
#define BITCOIN_UTIL_STRENCODINGS_H
 
#include <span.h>
#include <util/string.h>
 
#include <charconv>
#include <cstdint>
#include <iterator>
#include <optional>
#include <string>
#include <vector>
 
enum SafeChars {
    SAFE_CHARS_DEFAULT,
    SAFE_CHARS_UA_COMMENT,
    SAFE_CHARS_FILENAME,
    SAFE_CHARS_URI,
};
 
std::string SanitizeString(std::string_view str, int rule = SAFE_CHARS_DEFAULT);
template <typename Byte = std::byte>
std::optional<std::vector<Byte>> TryParseHex(std::string_view str);
template <typename Byte = uint8_t>
std::vector<Byte> ParseHex(std::string_view hex_str) {
    return TryParseHex<Byte>(hex_str).value_or(std::vector<Byte>{});
}
signed char HexDigit(char c);
bool IsHex(std::string_view str);
bool IsHexNumber(std::string_view str);
std::optional<std::vector<uint8_t>> DecodeBase64(std::string_view str);
std::string EncodeBase64(Span<const uint8_t> input);
inline std::string EncodeBase64(Span<const std::byte> input) {
    return EncodeBase64(MakeUCharSpan(input));
}
inline std::string EncodeBase64(std::string_view str) {
    return EncodeBase64(MakeUCharSpan(str));
}
std::optional<std::vector<uint8_t>> DecodeBase32(std::string_view str);
 
std::string EncodeBase32(Span<const uint8_t> input, bool pad = true);
 
std::string EncodeBase32(std::string_view str, bool pad = true);
 
void SplitHostPort(std::string_view in, uint16_t &portOut,
                   std::string &hostOut);
 
// LocaleIndependentAtoi is provided for backwards compatibility reasons.
//
// New code should use ToIntegral or the ParseInt* functions which provide parse
// error feedback.
//
// The goal of LocaleIndependentAtoi is to replicate the exact defined behaviour
// of atoi and atoi64 as they behave under the "C" locale.
template <typename T> T LocaleIndependentAtoi(const std::string &str) {
    static_assert(std::is_integral<T>::value);
    T result;
    // Emulate atoi(...) handling of white space and leading +/-.
    std::string s = TrimString(str);
    if (!s.empty() && s[0] == '+') {
        if (s.length() >= 2 && s[1] == '-') {
            return 0;
        }
        s = s.substr(1);
    }
    auto [_, error_condition] =
        std::from_chars(s.data(), s.data() + s.size(), result);
    if (error_condition != std::errc{}) {
        return 0;
    }
    return result;
}
 
constexpr bool IsDigit(char c) {
    return c >= '0' && c <= '9';
}
 
constexpr inline bool IsSpace(char c) noexcept {
    return c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' ||
           c == '\v';
}
 
template <typename T> std::optional<T> ToIntegral(std::string_view str) {
    static_assert(std::is_integral<T>::value);
    T result;
    const auto [first_nonmatching, error_condition] =
        std::from_chars(str.data(), str.data() + str.size(), result);
    if (first_nonmatching != str.data() + str.size() ||
        error_condition != std::errc{}) {
        return std::nullopt;
    }
    return result;
}
 
[[nodiscard]] bool ParseInt32(std::string_view str, int32_t *out);
 
[[nodiscard]] bool ParseInt64(std::string_view str, int64_t *out);
 
[[nodiscard]] bool ParseUInt8(std::string_view str, uint8_t *out);
 
[[nodiscard]] bool ParseUInt16(std::string_view str, uint16_t *out);
 
[[nodiscard]] bool ParseUInt32(std::string_view str, uint32_t *out);
 
[[nodiscard]] bool ParseUInt64(std::string_view str, uint64_t *out);
 
std::string HexStr(const Span<const uint8_t> s);
inline std::string HexStr(const Span<const char> s) {
    return HexStr(MakeUCharSpan(s));
}
inline std::string HexStr(const Span<const std::byte> s) {
    return HexStr(MakeUCharSpan(s));
}
 
std::string FormatParagraph(std::string_view in, size_t width = 79,
                            size_t indent = 0);
 
template <typename T> bool TimingResistantEqual(const T &a, const T &b) {
    if (b.size() == 0) {
        return a.size() == 0;
    }
    size_t accumulator = a.size() ^ b.size();
    for (size_t i = 0; i < a.size(); i++) {
        accumulator |= size_t(a[i] ^ b[i % b.size()]);
    }
    return accumulator == 0;
}
 
[[nodiscard]] bool ParseFixedPoint(std::string_view, int decimals,
                                   int64_t *amount_out);
 
namespace {
struct IntIdentity {
    [[maybe_unused]] int operator()(int x) const { return x; }
};
 
} // namespace
 
template <int frombits, int tobits, bool pad, typename O, typename It,
          typename I = IntIdentity>
bool ConvertBits(O outfn, It it, It end, I infn = {}) {
    size_t acc = 0;
    size_t bits = 0;
    constexpr size_t maxv = (1 << tobits) - 1;
    constexpr size_t max_acc = (1 << (frombits + tobits - 1)) - 1;
    while (it != end) {
        int v = infn(*it);
        if (v < 0) {
            return false;
        }
        acc = ((acc << frombits) | v) & max_acc;
        bits += frombits;
        while (bits >= tobits) {
            bits -= tobits;
            outfn((acc >> bits) & maxv);
        }
        ++it;
    }
 
    if (pad) {
        if (bits) {
            outfn((acc << (tobits - bits)) & maxv);
        }
    } else if (bits >= frombits || ((acc << (tobits - bits)) & maxv)) {
        return false;
    }
 
    return true;
}
 
constexpr char ToLower(char c) {
    return (c >= 'A' && c <= 'Z' ? (c - 'A') + 'a' : c);
}
 
std::string ToLower(std::string_view str);
 
constexpr char ToUpper(char c) {
    return (c >= 'a' && c <= 'z' ? (c - 'a') + 'A' : c);
}
 
std::string ToUpper(std::string_view str);
 
std::string Capitalize(std::string str);
 
#endif // BITCOIN_UTIL_STRENCODINGS_H