Base32 encoding/decoding
This commit is contained in:
Pieter Wuille
parent
a08e182698
commit
c4c99ade65
187
src/util.cpp
187
src/util.cpp
@ -702,6 +702,193 @@ string DecodeBase64(const string& str)
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return string((const char*)&vchRet[0], vchRet.size());
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}
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string EncodeBase32(const unsigned char* pch, size_t len)
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{
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static const char *pbase32 = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
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string strRet="";
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strRet.reserve((len+4)/5*8);
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int mode=0, left=0;
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const unsigned char *pchEnd = pch+len;
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while (pch<pchEnd)
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{
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int enc = *(pch++);
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switch (mode)
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{
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case 0: // we have no bits
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strRet += pbase32[enc >> 3];
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left = (enc & 7) << 2;
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mode = 1;
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break;
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case 1: // we have three bits
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strRet += pbase32[left | (enc >> 6)];
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strRet += pbase32[(enc >> 1) & 31];
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left = (enc & 1) << 4;
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mode = 2;
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break;
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case 2: // we have one bit
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strRet += pbase32[left | (enc >> 4)];
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left = (enc & 15) << 1;
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mode = 3;
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break;
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case 3: // we have four bits
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strRet += pbase32[left | (enc >> 7)];
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strRet += pbase32[(enc >> 2) & 31];
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left = (enc & 3) << 3;
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mode = 4;
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break;
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case 4: // we have two bits
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strRet += pbase32[left | (enc >> 5)];
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strRet += pbase32[enc & 31];
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mode = 0;
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}
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}
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static const int nPadding[5] = {0, 6, 4, 3, 1};
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if (mode)
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{
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strRet += pbase32[left];
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for (int n=0; n<nPadding[mode]; n++)
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strRet += '=';
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}
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return strRet;
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}
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string EncodeBase32(const string& str)
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{
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return EncodeBase32((const unsigned char*)str.c_str(), str.size());
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}
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vector<unsigned char> DecodeBase32(const char* p, bool* pfInvalid)
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{
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static const int decode32_table[256] =
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{
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 0, 1, 2,
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3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
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23, 24, 25, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
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};
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if (pfInvalid)
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*pfInvalid = false;
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vector<unsigned char> vchRet;
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vchRet.reserve((strlen(p))*5/8);
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int mode = 0;
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int left = 0;
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while (1)
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{
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int dec = decode32_table[(unsigned char)*p];
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if (dec == -1) break;
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p++;
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switch (mode)
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{
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case 0: // we have no bits and get 5
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left = dec;
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mode = 1;
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break;
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case 1: // we have 5 bits and keep 2
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vchRet.push_back((left<<3) | (dec>>2));
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left = dec & 3;
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mode = 2;
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break;
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case 2: // we have 2 bits and keep 7
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left = left << 5 | dec;
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mode = 3;
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break;
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case 3: // we have 7 bits and keep 4
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vchRet.push_back((left<<1) | (dec>>4));
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left = dec & 15;
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mode = 4;
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break;
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case 4: // we have 4 bits, and keep 1
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vchRet.push_back((left<<4) | (dec>>1));
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left = dec & 1;
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mode = 5;
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break;
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case 5: // we have 1 bit, and keep 6
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left = left << 5 | dec;
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mode = 6;
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break;
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case 6: // we have 6 bits, and keep 3
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vchRet.push_back((left<<2) | (dec>>3));
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left = dec & 7;
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mode = 7;
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break;
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case 7: // we have 3 bits, and keep 0
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vchRet.push_back((left<<5) | dec);
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mode = 0;
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break;
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}
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}
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if (pfInvalid)
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switch (mode)
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{
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case 0: // 8n base32 characters processed: ok
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break;
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case 1: // 8n+1 base32 characters processed: impossible
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case 3: // +3
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case 6: // +6
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*pfInvalid = true;
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break;
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case 2: // 8n+2 base32 characters processed: require '======'
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if (left || p[0] != '=' || p[1] != '=' || p[2] != '=' || p[3] != '=' || p[4] != '=' || p[5] != '=' || decode32_table[(unsigned char)p[6]] != -1)
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*pfInvalid = true;
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break;
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case 4: // 8n+4 base32 characters processed: require '===='
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if (left || p[0] != '=' || p[1] != '=' || p[2] != '=' || p[3] != '=' || decode32_table[(unsigned char)p[4]] != -1)
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*pfInvalid = true;
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break;
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case 5: // 8n+5 base32 characters processed: require '==='
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if (left || p[0] != '=' || p[1] != '=' || p[2] != '=' || decode32_table[(unsigned char)p[3]] != -1)
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*pfInvalid = true;
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break;
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case 7: // 8n+7 base32 characters processed: require '='
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if (left || p[0] != '=' || decode32_table[(unsigned char)p[1]] != -1)
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*pfInvalid = true;
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break;
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}
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return vchRet;
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}
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string DecodeBase32(const string& str)
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{
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vector<unsigned char> vchRet = DecodeBase32(str.c_str());
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return string((const char*)&vchRet[0], vchRet.size());
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}
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bool WildcardMatch(const char* psz, const char* mask)
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{
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@ -146,6 +146,10 @@ std::vector<unsigned char> DecodeBase64(const char* p, bool* pfInvalid = NULL);
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std::string DecodeBase64(const std::string& str);
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std::string EncodeBase64(const unsigned char* pch, size_t len);
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std::string EncodeBase64(const std::string& str);
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std::vector<unsigned char> DecodeBase32(const char* p, bool* pfInvalid = NULL);
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std::string DecodeBase32(const std::string& str);
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std::string EncodeBase32(const unsigned char* pch, size_t len);
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std::string EncodeBase32(const std::string& str);
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void ParseParameters(int argc, const char*const argv[]);
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bool WildcardMatch(const char* psz, const char* mask);
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bool WildcardMatch(const std::string& str, const std::string& mask);
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