Inline base64 encoder/decoder

This replaces the openssl-based base64 encoder and decoder with a more
efficient internal one. Tested against the rfc4648 test vectors.

Decoder is based on JoelKatz' version.

src/bitcoinrpc.cpp

@@ -1811,25 +1811,6 @@ int ReadHTTP(std::basic_istream<char>& stream, map<string, string>& mapHeadersRe
     return nStatus;
 }
 
-string EncodeBase64(string s)
-{
-    BIO *b64, *bmem;
-    BUF_MEM *bptr;
-
-    b64 = BIO_new(BIO_f_base64());
-    BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
-    bmem = BIO_new(BIO_s_mem());
-    b64 = BIO_push(b64, bmem);
-    BIO_write(b64, s.c_str(), s.size());
-    BIO_flush(b64);
-    BIO_get_mem_ptr(b64, &bptr);
-
-    string result(bptr->data, bptr->length);
-    BIO_free_all(b64);
-
-    return result;
-}
-
 bool HTTPAuthorized(map<string, string>& mapHeaders)
 {
     string strAuth = mapHeaders["authorization"];

src/util.cpp

@@ -443,7 +443,6 @@ vector<unsigned char> ParseHex(const string& str)
     return ParseHex(str.c_str());
 }
 
-
 void ParseParameters(int argc, char* argv[])
 {
     mapArgs.clear();
@@ -470,8 +469,61 @@ void ParseParameters(int argc, char* argv[])
     }
 }
 
-static const int decode64_table[256]=
+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,
@@ -485,21 +537,23 @@ 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, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
-};
+    };
 
-std::string DecodeBase64(const std::string &s)
-{
-    char buf[1024];
-    if(s.length()>512) return "";
-    char *optr=buf;
+    if (pfInvalid)
+        *pfInvalid = false;
 
-    int dec, mode=0, left=0;
-    size_t index=0;
-    for (int i=0; i<s.length(); i++)
+    vector<unsigned char> vchRet;
+    vchRet.reserve(strlen(p)*3/4);
+
+    int mode = 0;
+    int left = 0;
+
+    while (1)
     {
-         dec=decode64_table[s[i]];
-         if(dec==-1) break;
-         switch(mode)
+         int dec = decode64_table[*p];
+         if (dec == -1) break;
+         p++;
+         switch (mode)
          {
              case 0: // we have no bits and get 6
                  left = dec;
@@ -507,28 +561,53 @@ std::string DecodeBase64(const std::string &s)
                  break;
 
               case 1: // we have 6 bits and keep 4
-                 *optr++ = (left<<2) | (dec>>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
-                  *optr++ = (left<<4) | (dec>>2);
+                 vchRet.push_back((left<<4) | (dec>>2));
                  left = dec & 3;
                  mode = 3;
                  break;
 
              case 3: // we have 2 bits and get 6
-                 *optr++ = (left<<6) | dec;
-                 mode=0;
+                 vchRet.push_back((left<<6) | dec);
+                 mode = 0;
                  break;
          }
     }
 
-    *optr=0;   
-    return buf;
+    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[p[2]] != -1)
+                    *pfInvalid = true;
+                break;
+
+            case 3: // 4n+3 base64 characters processed: require '='
+                if (left || p[0] != '=' || decode64_table[p[1]] != -1)
+                    *pfInvalid = true;
+                break;
+        }
+
+    return vchRet;
 }
 
+string DecodeBase64(const string& str)
+{
+    vector<unsigned char> vchRet = DecodeBase64(str.c_str());
+    return string((const char*)&vchRet[0], vchRet.size());
+}
 
 
 bool WildcardMatch(const char* psz, const char* mask)

src/util.h

@@ -178,6 +178,10 @@ bool ParseMoney(const std::string& str, int64& nRet);
 bool ParseMoney(const char* pszIn, int64& nRet);
 std::vector<unsigned char> ParseHex(const char* psz);
 std::vector<unsigned char> ParseHex(const std::string& str);
+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);
 void ParseParameters(int argc, char* argv[]);
 const char* wxGetTranslation(const char* psz);
 bool WildcardMatch(const char* psz, const char* mask);
@@ -201,7 +205,6 @@ void SetMockTime(int64 nMockTimeIn);
 int64 GetAdjustedTime();
 void AddTimeData(unsigned int ip, int64 nTime);
 std::string FormatFullVersion();
-std::string DecodeBase64(const std::string &s);