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Diffstat (limited to 'src/org/spongycastle/util/encoders/Base64Encoder.java')
-rw-r--r--src/org/spongycastle/util/encoders/Base64Encoder.java298
1 files changed, 298 insertions, 0 deletions
diff --git a/src/org/spongycastle/util/encoders/Base64Encoder.java b/src/org/spongycastle/util/encoders/Base64Encoder.java
new file mode 100644
index 00000000..84060707
--- /dev/null
+++ b/src/org/spongycastle/util/encoders/Base64Encoder.java
@@ -0,0 +1,298 @@
+package org.spongycastle.util.encoders;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+public class Base64Encoder
+ implements Encoder
+{
+ protected final 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 final 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,
+ OutputStream out)
+ throws IOException
+ {
+ 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;
+
+ out.write(encodingTable[(a1 >>> 2) & 0x3f]);
+ out.write(encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3f]);
+ out.write(encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3f]);
+ out.write(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;
+
+ out.write(encodingTable[b1]);
+ out.write(encodingTable[b2]);
+ out.write(padding);
+ out.write(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;
+
+ out.write(encodingTable[b1]);
+ out.write(encodingTable[b2]);
+ out.write(encodingTable[b3]);
+ out.write(padding);
+ break;
+ }
+
+ return (dataLength / 3) * 4 + ((modulus == 0) ? 0 : 4);
+ }
+
+ private boolean 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,
+ OutputStream out)
+ throws IOException
+ {
+ 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++]];
+
+ out.write((b1 << 2) | (b2 >> 4));
+ out.write((b2 << 4) | (b3 >> 2));
+ out.write((b3 << 6) | b4);
+
+ outLen += 3;
+
+ i = nextI(data, i, finish);
+ }
+
+ outLen += decodeLastBlock(out, (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 decode(
+ String data,
+ OutputStream out)
+ throws IOException
+ {
+ byte b1, b2, b3, b4;
+ int length = 0;
+
+ int end = data.length();
+
+ while (end > 0)
+ {
+ if (!ignore(data.charAt(end - 1)))
+ {
+ break;
+ }
+
+ end--;
+ }
+
+ int i = 0;
+ int finish = end - 4;
+
+ i = nextI(data, i, finish);
+
+ while (i < finish)
+ {
+ b1 = decodingTable[data.charAt(i++)];
+
+ i = nextI(data, i, finish);
+
+ b2 = decodingTable[data.charAt(i++)];
+
+ i = nextI(data, i, finish);
+
+ b3 = decodingTable[data.charAt(i++)];
+
+ i = nextI(data, i, finish);
+
+ b4 = decodingTable[data.charAt(i++)];
+
+ out.write((b1 << 2) | (b2 >> 4));
+ out.write((b2 << 4) | (b3 >> 2));
+ out.write((b3 << 6) | b4);
+
+ length += 3;
+
+ i = nextI(data, i, finish);
+ }
+
+ length += decodeLastBlock(out, data.charAt(end - 4), data.charAt(end - 3), data.charAt(end - 2), data.charAt(end - 1));
+
+ return length;
+ }
+
+ private int decodeLastBlock(OutputStream out, char c1, char c2, char c3, char c4)
+ throws IOException
+ {
+ byte b1, b2, b3, b4;
+
+ if (c3 == padding)
+ {
+ b1 = decodingTable[c1];
+ b2 = decodingTable[c2];
+
+ out.write((b1 << 2) | (b2 >> 4));
+
+ return 1;
+ }
+ else if (c4 == padding)
+ {
+ b1 = decodingTable[c1];
+ b2 = decodingTable[c2];
+ b3 = decodingTable[c3];
+
+ out.write((b1 << 2) | (b2 >> 4));
+ out.write((b2 << 4) | (b3 >> 2));
+
+ return 2;
+ }
+ else
+ {
+ b1 = decodingTable[c1];
+ b2 = decodingTable[c2];
+ b3 = decodingTable[c3];
+ b4 = decodingTable[c4];
+
+ out.write((b1 << 2) | (b2 >> 4));
+ out.write((b2 << 4) | (b3 >> 2));
+ out.write((b3 << 6) | b4);
+
+ return 3;
+ }
+ }
+
+ private int nextI(String data, int i, int finish)
+ {
+ while ((i < finish) && ignore(data.charAt(i)))
+ {
+ i++;
+ }
+ return i;
+ }
+}
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