From c4c99ade653e8e8f62ed4af4c22e196c8310d0d8 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Sun, 22 Jan 2012 20:32:58 +0100 Subject: [PATCH] Base32 encoding/decoding --- src/util.cpp | 187 +++++++++++++++++++++++++++++++++++++++++++++++++++ src/util.h | 4 ++ 2 files changed, 191 insertions(+) diff --git a/src/util.cpp b/src/util.cpp index b07c9c1b7..931d27ba0 100644 --- a/src/util.cpp +++ b/src/util.cpp @@ -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> 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 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 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 vchRet = DecodeBase32(str.c_str()); + return string((const char*)&vchRet[0], vchRet.size()); +} + bool WildcardMatch(const char* psz, const char* mask) { diff --git a/src/util.h b/src/util.h index c9b2b2f17..058f90979 100644 --- a/src/util.h +++ b/src/util.h @@ -146,6 +146,10 @@ std::vector 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 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);