diff options
Diffstat (limited to 'crypto/src/util/encoders/Base64Encoder.cs')
| -rw-r--r-- | crypto/src/util/encoders/Base64Encoder.cs | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/crypto/src/util/encoders/Base64Encoder.cs b/crypto/src/util/encoders/Base64Encoder.cs new file mode 100644 index 000000000..c94ce9d3c --- /dev/null +++ b/crypto/src/util/encoders/Base64Encoder.cs @@ -0,0 +1,307 @@ +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() + { + for (int i = 0; i < encodingTable.Length; i++) + { + decodingTable[encodingTable[i]] = (byte)i; + } + } + + public Base64Encoder() + { + InitialiseDecodingTable(); + } + + /** + * encode the input data producing a base 64 output stream. + * + * @return the number of bytes produced. + */ + public int Encode( + byte[] data, + int off, + int length, + Stream outStream) + { + int modulus = length % 3; + int dataLength = (length - modulus); + int a1, a2, a3; + + for (int i = off; i < off + dataLength; i += 3) + { + a1 = data[i] & 0xff; + a2 = data[i + 1] & 0xff; + a3 = data[i + 2] & 0xff; + + outStream.WriteByte(encodingTable[(int) ((uint) a1 >> 2) & 0x3f]); + outStream.WriteByte(encodingTable[((a1 << 4) | (int) ((uint) a2 >> 4)) & 0x3f]); + outStream.WriteByte(encodingTable[((a2 << 2) | (int) ((uint) a3 >> 6)) & 0x3f]); + outStream.WriteByte(encodingTable[a3 & 0x3f]); + } + + /* + * process the tail end. + */ + int b1, b2, b3; + int d1, d2; + + switch (modulus) + { + case 0: /* nothing left to do */ + break; + case 1: + d1 = data[off + dataLength] & 0xff; + b1 = (d1 >> 2) & 0x3f; + b2 = (d1 << 4) & 0x3f; + + outStream.WriteByte(encodingTable[b1]); + outStream.WriteByte(encodingTable[b2]); + outStream.WriteByte(padding); + outStream.WriteByte(padding); + break; + case 2: + d1 = data[off + dataLength] & 0xff; + d2 = data[off + dataLength + 1] & 0xff; + + b1 = (d1 >> 2) & 0x3f; + b2 = ((d1 << 4) | (d2 >> 4)) & 0x3f; + b3 = (d2 << 2) & 0x3f; + + outStream.WriteByte(encodingTable[b1]); + outStream.WriteByte(encodingTable[b2]); + outStream.WriteByte(encodingTable[b3]); + outStream.WriteByte(padding); + break; + } + + return (dataLength / 3) * 4 + ((modulus == 0) ? 0 : 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; + 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++]]; + + outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4))); + outStream.WriteByte((byte)((b2 << 4) | (b3 >> 2))); + outStream.WriteByte((byte)((b3 << 6) | b4)); + + outLen += 3; + + i = nextI(data, i, finish); + } + + outLen += decodeLastBlock(outStream, (char)data[end - 4], (char)data[end - 3], (char)data[end - 2], (char)data[end - 1]); + + 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++]]; + + 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) + { + byte b1 = decodingTable[c1]; + byte b2 = decodingTable[c2]; + + outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4))); + + return 1; + } + + if (c4 == padding) + { + byte b1 = decodingTable[c1]; + byte b2 = decodingTable[c2]; + byte b3 = decodingTable[c3]; + + 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]; + + 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; + } + } +} |