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Base32 encoding/decoding

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pull/1174/head
Pieter Wuille 13 years ago
parent a08e182698
commit c4c99ade65
2 changed files with 191 additions and 0 deletions
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187
src/util.cpp
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@ -702,6 +702,193 @@ string DecodeBase64(const string& str)
return string((const char*)&vchRet[0], vchRet.size());
}
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 string((const char*)&vchRet[0], vchRet.size());
}
bool WildcardMatch(const char* psz, const char* mask)
{

4
src/util.h
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@ -146,6 +146,10 @@ std::vector<unsigned char> DecodeBase64(const char* p, bool* pfInvalid = NULL);
std::string DecodeBase64(const std::string& str);
std::string EncodeBase64(const unsigned char* pch, size_t len);
std::string EncodeBase64(const std::string& str);
std::vector<unsigned char> DecodeBase32(const char* p, bool* pfInvalid = NULL);
std::string DecodeBase32(const std::string& str);
std::string EncodeBase32(const unsigned char* pch, size_t len);
std::string EncodeBase32(const std::string& str);
void ParseParameters(int argc, const char*const argv[]);
bool WildcardMatch(const char* psz, const char* mask);
bool WildcardMatch(const std::string& str, const std::string& mask);

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