utilstrencodings.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2015 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 "utilstrencodings.h"

#include "tinyformat.h"

#include <errno.h>
#include <limits>
#include <cstdlib>
#include <cstring>

using namespace std;







string EncodeBase64(const unsigned char* pch, size_t len)
{
    static const char *pbase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    string strRet="";
    strRet.reserve((len+2)/3*4);

    int mode=0, left=0;
    const unsigned char *pchEnd = pch+len;

    while (pch<pchEnd)
    {
        int enc = *(pch++);
        switch (mode)
        {
            case 0: // we have no bits
                strRet += pbase64[enc >> 2];
                left = (enc & 3) << 4;
                mode = 1;
                break;

            case 1: // we have two bits
                strRet += pbase64[left | (enc >> 4)];
                left = (enc & 15) << 2;
                mode = 2;
                break;

            case 2: // we have four bits
                strRet += pbase64[left | (enc >> 6)];
                strRet += pbase64[enc & 63];
                mode = 0;
                break;
        }
    }

    if (mode)
    {
        strRet += pbase64[left];
        strRet += '=';
        if (mode == 1)
            strRet += '=';
    }

    return strRet;
}

string EncodeBase64(const string& str)
{
    return EncodeBase64((const unsigned char*)str.c_str(), str.size());
}

vector<unsigned char> DecodeBase64(const char* p, bool* pfInvalid)
{
    static const int 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 (pfInvalid)
        *pfInvalid = false;

    vector<unsigned char> vchRet;
    vchRet.reserve(strlen(p)*3/4);

    int mode = 0;
    int left = 0;

    while (1)
    {
         int dec = decode64_table[(unsigned char)*p];
         if (dec == -1) break;
         p++;
         switch (mode)
         {
             case 0: // we have no bits and get 6
                 left = dec;
                 mode = 1;
                 break;

              case 1: // we have 6 bits and keep 4
                  vchRet.push_back((left<<2) | (dec>>4));
                  left = dec & 15;
                  mode = 2;
                  break;

             case 2: // we have 4 bits and get 6, we keep 2
                 vchRet.push_back((left<<4) | (dec>>2));
                 left = dec & 3;
                 mode = 3;
                 break;

             case 3: // we have 2 bits and get 6
                 vchRet.push_back((left<<6) | dec);
                 mode = 0;
                 break;
         }
    }

    if (pfInvalid)
        switch (mode)
        {
            case 0: // 4n base64 characters processed: ok
                break;

            case 1: // 4n+1 base64 character processed: impossible
                *pfInvalid = true;
                break;

            case 2: // 4n+2 base64 characters processed: require '=='
                if (left || p[0] != '=' || p[1] != '=' || decode64_table[(unsigned char)p[2]] != -1)
                    *pfInvalid = true;
                break;

            case 3: // 4n+3 base64 characters processed: require '='
                if (left || p[0] != '=' || decode64_table[(unsigned char)p[1]] != -1)
                    *pfInvalid = true;
                break;
        }

    return vchRet;
}

string DecodeBase64(const string& str)
{
    vector<unsigned char> vchRet = DecodeBase64(str.c_str());
    return (vchRet.size() == 0) ? string() : string((const char*)&vchRet[0], vchRet.size());
}

// Base64 encoding with secure memory allocation
SecureString EncodeBase64Secure(const SecureString& input)
{
    // Init openssl BIO with base64 filter and memory output
    BIO *b64, *mem;
    b64 = BIO_new(BIO_f_base64());
    BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL); // No newlines in output
    mem = BIO_new(BIO_s_mem());
    BIO_push(b64, mem);

    // Decode the string
    BIO_write(b64, &input[0], input.size());
    (void) BIO_flush(b64);

    // Create output variable from buffer mem ptr
    BUF_MEM *bptr;
    BIO_get_mem_ptr(b64, &bptr);
    SecureString output(bptr->data, bptr->length);

    // Cleanse secure data buffer from memory
    OPENSSL_cleanse((void *) bptr->data, bptr->length);

    // Free memory
    BIO_free_all(b64);
    return output;
}

// Base64 decoding with secure memory allocation
SecureString DecodeBase64Secure(const SecureString& input)
{
    SecureString output;

    // Init openssl BIO with base64 filter and memory input
    BIO *b64, *mem;
    b64 = BIO_new(BIO_f_base64());
    BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL); //Do not use newlines to flush buffer
    mem = BIO_new_mem_buf((void *) &input[0], input.size());
    BIO_push(b64, mem);

    // Prepare buffer to receive decoded data
    if(input.size() % 4 != 0) {
        throw runtime_error("Input length should be a multiple of 4");
    }
    size_t nMaxLen = input.size() / 4 * 3; // upper bound, guaranteed divisible by 4
    output.resize(nMaxLen);

    // Decode the string
    size_t nLen;
    nLen = BIO_read(b64, (void *) &output[0], input.size());
    output.resize(nLen);

    // Free memory
    BIO_free_all(b64);
    return output;
}




string EncodeBase32(const unsigned char* pch, size_t len)
{
    static const char *pbase32 = "abcdefghijklmnopqrstuvwxyz234567";

    string strRet="";
    strRet.reserve((len+4)/5*8);

    int mode=0, left=0;
    const unsigned char *pchEnd = pch+len;

    while (pch<pchEnd)
    {
        int enc = *(pch++);
        switch (mode)
        {
            case 0: // we have no bits
                strRet += pbase32[enc >> 3];
                left = (enc & 7) << 2;
                mode = 1;
                break;

            case 1: // we have three bits
                strRet += pbase32[left | (enc >> 6)];
                strRet += pbase32[(enc >> 1) & 31];
                left = (enc & 1) << 4;
                mode = 2;
                break;

            case 2: // we have one bit
                strRet += pbase32[left | (enc >> 4)];
                left = (enc & 15) << 1;
                mode = 3;
                break;

            case 3: // we have four bits
                strRet += pbase32[left | (enc >> 7)];
                strRet += pbase32[(enc >> 2) & 31];
                left = (enc & 3) << 3;
                mode = 4;
                break;

            case 4: // we have two bits
                strRet += pbase32[left | (enc >> 5)];
                strRet += pbase32[enc & 31];
                mode = 0;
        }
    }

    static const int nPadding[5] = {0, 6, 4, 3, 1};
    if (mode)
    {
        strRet += pbase32[left];
        for (int n=0; n<nPadding[mode]; n++)
             strRet += '=';
    }

    return strRet;
}

string EncodeBase32(const string& str)
{
    return EncodeBase32((const unsigned char*)str.c_str(), str.size());
}

vector<unsigned char> DecodeBase32(const char* p, bool* pfInvalid)
{
    static const int 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 (pfInvalid)
        *pfInvalid = false;

    vector<unsigned char> vchRet;
    vchRet.reserve((strlen(p))*5/8);

    int mode = 0;
    int left = 0;

    while (1)
    {
         int dec = decode32_table[(unsigned char)*p];
         if (dec == -1) break;
         p++;
         switch (mode)
         {
             case 0: // we have no bits and get 5
                 left = dec;
                 mode = 1;
                 break;

              case 1: // we have 5 bits and keep 2
                  vchRet.push_back((left<<3) | (dec>>2));
                  left = dec & 3;
                  mode = 2;
                  break;

             case 2: // we have 2 bits and keep 7
                 left = left << 5 | dec;
                 mode = 3;
                 break;

             case 3: // we have 7 bits and keep 4
                 vchRet.push_back((left<<1) | (dec>>4));
                 left = dec & 15;
                 mode = 4;
                 break;

             case 4: // we have 4 bits, and keep 1
                 vchRet.push_back((left<<4) | (dec>>1));
                 left = dec & 1;
                 mode = 5;
                 break;

             case 5: // we have 1 bit, and keep 6
                 left = left << 5 | dec;
                 mode = 6;
                 break;

             case 6: // we have 6 bits, and keep 3
                 vchRet.push_back((left<<2) | (dec>>3));
                 left = dec & 7;
                 mode = 7;
                 break;

             case 7: // we have 3 bits, and keep 0
                 vchRet.push_back((left<<5) | dec);
                 mode = 0;
                 break;
         }
    }

    if (pfInvalid)
        switch (mode)
        {
            case 0: // 8n base32 characters processed: ok
                break;

            case 1: // 8n+1 base32 characters processed: impossible
            case 3: //   +3
            case 6: //   +6
                *pfInvalid = true;
                break;

            case 2: // 8n+2 base32 characters processed: require '======'
                if (left || p[0] != '=' || p[1] != '=' || p[2] != '=' || p[3] != '=' || p[4] != '=' || p[5] != '=' || decode32_table[(unsigned char)p[6]] != -1)
                    *pfInvalid = true;
                break;

            case 4: // 8n+4 base32 characters processed: require '===='
                if (left || p[0] != '=' || p[1] != '=' || p[2] != '=' || p[3] != '=' || decode32_table[(unsigned char)p[4]] != -1)
                    *pfInvalid = true;
                break;

            case 5: // 8n+5 base32 characters processed: require '==='
                if (left || p[0] != '=' || p[1] != '=' || p[2] != '=' || decode32_table[(unsigned char)p[3]] != -1)
                    *pfInvalid = true;
                break;

            case 7: // 8n+7 base32 characters processed: require '='
                if (left || p[0] != '=' || decode32_table[(unsigned char)p[1]] != -1)
                    *pfInvalid = true;
                break;
        }

    return vchRet;
}

string DecodeBase32(const string& str)
{
    vector<unsigned char> vchRet = DecodeBase32(str.c_str());
    return (vchRet.size() == 0) ? string() : string((const char*)&vchRet[0], vchRet.size());
}

bool ParseInt32(const std::string& str, int32_t *out)
{
    char *endp = NULL;
    errno = 0; // strtol will not set errno if valid
    long int n = strtol(str.c_str(), &endp, 10);
    if(out) *out = (int)n;
    // Note that strtol returns a *long int*, so even if strtol doesn't report a over/underflow
    // we still have to check that the returned value is within the range of an *int32_t*. On 64-bit
    // platforms the size of these types may be different.
    return endp && *endp == 0 && !errno &&
        n >= std::numeric_limits<int32_t>::min() &&
        n <= std::numeric_limits<int32_t>::max();
}

std::string FormatParagraph(const std::string in, size_t width, size_t indent)
{
    std::stringstream out;
    size_t col = 0;
    size_t ptr = 0;
    while(ptr < in.size())
    {
        // Find beginning of next word
        ptr = in.find_first_not_of(' ', ptr);
        if (ptr == std::string::npos)
            break;
        // Find end of next word
        size_t endword = in.find_first_of(' ', ptr);
        if (endword == std::string::npos)
            endword = in.size();
        // Add newline and indentation if this wraps over the allowed width
        if (col > 0)
        {
            if ((col + endword - ptr) > width)
            {
                out << '\n';
                for(size_t i=0; i<indent; ++i)
                    out << ' ';
                col = 0;
            } else
                out << ' ';
        }
        // Append word
        out << in.substr(ptr, endword - ptr);
        col += endword - ptr + 1;
        ptr = endword;
    }
    return out.str();
}

std::string i64tostr(int64_t n)
{
    return strprintf("%d", n);
}

std::string itostr(int n)
{
    return strprintf("%d", n);
}

int64_t atoi64(const char* psz)
{
#ifdef _MSC_VER
    return _atoi64(psz);
#else
    return strtoll(psz, NULL, 10);
#endif
}

int64_t atoi64(const std::string& str)
{
#ifdef _MSC_VER
    return _atoi64(str.c_str());
#else
    return strtoll(str.c_str(), NULL, 10);
#endif
}

int atoi(const std::string& str)
{
    return atoi(str.c_str());
}