using System; using System.IO; namespace Org.BouncyCastle.Utilities.Encoders { public class Base64Encoder : IEncoder { protected readonly byte[] encodingTable = { (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G', (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N', (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g', (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n', (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z', (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/' }; protected byte padding = (byte)'='; /* * set up the decoding table. */ protected readonly byte[] decodingTable = new byte[128]; protected void InitialiseDecodingTable() { Arrays.Fill(decodingTable, (byte)0xff); for (int i = 0; i < encodingTable.Length; i++) { decodingTable[encodingTable[i]] = (byte)i; } } public Base64Encoder() { InitialiseDecodingTable(); } public int Encode(byte[] inBuf, int inOff, int inLen, byte[] outBuf, int outOff) { int inPos = inOff; int inEnd = inOff + inLen - 2; int outPos = outOff; while (inPos < inEnd) { uint a1 = inBuf[inPos++]; uint a2 = inBuf[inPos++]; uint a3 = inBuf[inPos++]; outBuf[outPos++] = encodingTable[(a1 >> 2) & 0x3F]; outBuf[outPos++] = encodingTable[((a1 << 4) | (a2 >> 4)) & 0x3F]; outBuf[outPos++] = encodingTable[((a2 << 2) | (a3 >> 6)) & 0x3F]; outBuf[outPos++] = encodingTable[a3 & 0x3F]; } switch (inLen - (inPos - inOff)) { case 1: { uint a1 = inBuf[inPos++]; outBuf[outPos++] = encodingTable[(a1 >> 2) & 0x3F]; outBuf[outPos++] = encodingTable[(a1 << 4) & 0x3F]; outBuf[outPos++] = padding; outBuf[outPos++] = padding; break; } case 2: { uint a1 = inBuf[inPos++]; uint a2 = inBuf[inPos++]; outBuf[outPos++] = encodingTable[(a1 >> 2) & 0x3F]; outBuf[outPos++] = encodingTable[((a1 << 4) | (a2 >> 4)) & 0x3F]; outBuf[outPos++] = encodingTable[(a2 << 2) & 0x3F]; outBuf[outPos++] = padding; break; } } return outPos - outOff; } /** * encode the input data producing a base 64 output stream. * * @return the number of bytes produced. */ public int Encode(byte[] buf, int off, int len, Stream outStream) { if (len < 0) return 0; byte[] tmp = new byte[72]; int remaining = len; while (remaining > 0) { int inLen = System.Math.Min(54, remaining); int outLen = Encode(buf, off, inLen, tmp, 0); outStream.Write(tmp, 0, outLen); off += inLen; remaining -= inLen; } return (len + 2) / 3 * 4; } private bool Ignore(char c) { return c == '\n' || c =='\r' || c == '\t' || c == ' '; } /** * decode the base 64 encoded byte data writing it to the given output stream, * whitespace characters will be ignored. * * @return the number of bytes produced. */ public int Decode(byte[] data, int off, int length, Stream outStream) { byte b1, b2, b3, b4; byte[] outBuffer = new byte[54]; // S/MIME standard int bufOff = 0; int outLen = 0; int end = off + length; while (end > off) { if (!Ignore((char)data[end - 1])) break; end--; } int i = off; int finish = end - 4; i = NextI(data, i, finish); while (i < finish) { b1 = decodingTable[data[i++]]; i = NextI(data, i, finish); b2 = decodingTable[data[i++]]; i = NextI(data, i, finish); b3 = decodingTable[data[i++]]; i = NextI(data, i, finish); b4 = decodingTable[data[i++]]; if ((b1 | b2 | b3 | b4) >= 0x80) throw new IOException("invalid characters encountered in base64 data"); outBuffer[bufOff++] = (byte)((b1 << 2) | (b2 >> 4)); outBuffer[bufOff++] = (byte)((b2 << 4) | (b3 >> 2)); outBuffer[bufOff++] = (byte)((b3 << 6) | b4); if (bufOff == outBuffer.Length) { outStream.Write(outBuffer, 0, bufOff); bufOff = 0; } outLen += 3; i = NextI(data, i, finish); } if (bufOff > 0) { outStream.Write(outBuffer, 0, bufOff); } int e0 = NextI(data, i, end); int e1 = NextI(data, e0 + 1, end); int e2 = NextI(data, e1 + 1, end); int e3 = NextI(data, e2 + 1, end); outLen += DecodeLastBlock(outStream, (char)data[e0], (char)data[e1], (char)data[e2], (char)data[e3]); return outLen; } private int NextI( byte[] data, int i, int finish) { while ((i < finish) && Ignore((char)data[i])) { i++; } return i; } /** * decode the base 64 encoded string data writing it to the given output stream, * whitespace characters will be ignored. * * @return the number of bytes produced. */ public int DecodeString(string data, Stream outStream) { // Platform Implementation // byte[] bytes = Convert.FromBase64String(data); // outStream.Write(bytes, 0, bytes.Length); // return bytes.Length; byte b1, b2, b3, b4; int length = 0; int end = data.Length; while (end > 0) { if (!Ignore(data[end - 1])) break; end--; } int i = 0; int finish = end - 4; i = NextI(data, i, finish); while (i < finish) { b1 = decodingTable[data[i++]]; i = NextI(data, i, finish); b2 = decodingTable[data[i++]]; i = NextI(data, i, finish); b3 = decodingTable[data[i++]]; i = NextI(data, i, finish); b4 = decodingTable[data[i++]]; if ((b1 | b2 | b3 | b4) >= 0x80) throw new IOException("invalid characters encountered in base64 data"); outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4))); outStream.WriteByte((byte)((b2 << 4) | (b3 >> 2))); outStream.WriteByte((byte)((b3 << 6) | b4)); length += 3; i = NextI(data, i, finish); } length += DecodeLastBlock(outStream, data[end - 4], data[end - 3], data[end - 2], data[end - 1]); return length; } private int DecodeLastBlock( Stream outStream, char c1, char c2, char c3, char c4) { if (c3 == padding) { if (c4 != padding) throw new IOException("invalid characters encountered at end of base64 data"); byte b1 = decodingTable[c1]; byte b2 = decodingTable[c2]; if ((b1 | b2) >= 0x80) throw new IOException("invalid characters encountered at end of base64 data"); outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4))); return 1; } if (c4 == padding) { byte b1 = decodingTable[c1]; byte b2 = decodingTable[c2]; byte b3 = decodingTable[c3]; if ((b1 | b2 | b3) >= 0x80) throw new IOException("invalid characters encountered at end of base64 data"); outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4))); outStream.WriteByte((byte)((b2 << 4) | (b3 >> 2))); return 2; } { byte b1 = decodingTable[c1]; byte b2 = decodingTable[c2]; byte b3 = decodingTable[c3]; byte b4 = decodingTable[c4]; if ((b1 | b2 | b3 | b4) >= 0x80) throw new IOException("invalid characters encountered at end of base64 data"); outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4))); outStream.WriteByte((byte)((b2 << 4) | (b3 >> 2))); outStream.WriteByte((byte)((b3 << 6) | b4)); return 3; } } private int NextI(string data, int i, int finish) { while ((i < finish) && Ignore(data[i])) { i++; } return i; } } }