diff options
author | Doug Zongker <dougz@android.com> | 2010-02-12 15:50:01 -0800 |
---|---|---|
committer | Doug Zongker <dougz@android.com> | 2010-02-12 17:13:56 -0800 |
commit | d2affae13dfdb116adaee1bb10aaaac80a885481 (patch) | |
tree | 2c12a5b5c6e4064d1587e2ece6f1f909657e8914 /core/java | |
parent | 190dd57fb843b1b5019ebdba32e44617c6bbc3d0 (diff) | |
download | frameworks_base-d2affae13dfdb116adaee1bb10aaaac80a885481.zip frameworks_base-d2affae13dfdb116adaee1bb10aaaac80a885481.tar.gz frameworks_base-d2affae13dfdb116adaee1bb10aaaac80a885481.tar.bz2 |
add a Base64 implementation to the API
b/1413917 - RFE: Base64 utility class
Change-Id: I11697859e1f78f596b92d2e03a49ed1be04ae42d
Diffstat (limited to 'core/java')
-rw-r--r-- | core/java/android/util/base64/Base64.java | 706 | ||||
-rw-r--r-- | core/java/android/util/base64/Base64InputStream.java | 169 | ||||
-rw-r--r-- | core/java/android/util/base64/Base64OutputStream.java | 153 |
3 files changed, 1028 insertions, 0 deletions
diff --git a/core/java/android/util/base64/Base64.java b/core/java/android/util/base64/Base64.java new file mode 100644 index 0000000..088de9f --- /dev/null +++ b/core/java/android/util/base64/Base64.java @@ -0,0 +1,706 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package android.util.base64; + +/** + * Utilities for encoding and decoding the Base64 encoding. See RFCs + * 2045 and 3548. + */ +public class Base64 { + /** + * Default values for encoder/decoder flags. + */ + public static final int DEFAULT = 0; + + /** + * Encoder flag bit to indicate you want the padding '=' + * characters at the end (if any) to be omitted. + */ + public static final int NO_PADDING = 1; + + /** + * Encoder flag bit to indicate you want all line terminators to + * be omitted (ie, the output will be on one long line). + */ + public static final int NO_WRAP = 2; + + /** + * Encoder flag bit to indicate you want lines to be ended with + * CRLF instead of just LF. Has no effect if {@code NO_WRAP} is + * specified as well. + */ + public static final int CRLF = 4; + + /** + * Encoder/decoder flag bit to indicate using the "web safe" + * variant of Base64 (see RFC 3548 section 4) where '-' and '_' + * are used in place of '+' and '/'. + */ + public static final int WEB_SAFE = 8; + + /** + * Flag to pass to Base64OutputStream to indicate that it should + * not close the output stream it is wrapping when it itself is + * closed. + */ + public static final int NO_CLOSE = 16; + + // -------------------------------------------------------- + // decoding + // -------------------------------------------------------- + + /** + * Lookup table for turning bytes into their position in the + * Base64 alphabet. + */ + private static final int DECODE[] = { + -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, -1, -2, -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, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -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, + }; + + /** + * Decode lookup table for the "web safe" variant (RFC 3548 + * sec. 4) where - and _ replace + and /. + */ + private static final int DECODE_WEBSAFE[] = { + -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, 62, -1, -1, + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -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, 63, + -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -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, + }; + + /** Non-data values in the DECODE arrays. */ + private static final int SKIP = -1; + private static final int EQUALS = -2; + + /** + * Decode the Base64-encoded data in input and return the data in + * a new byte array. + * + * The padding '=' characters at the end are considered optional, but + * if any are present, there must be the correct number of them. + * + * @param input the input String to decode, which is converted to + * bytes using the default charset + * @param flags controls certain features of the decoded output. + * Pass {@code DEFAULT} to decode standard Base64. + * + * @throws IllegalArgumentException if the input contains + * incorrect padding + */ + public static byte[] decode(String str, int flags) { + return decode(str.getBytes(), flags); + } + + /** + * Decode the Base64-encoded data in input and return the data in + * a new byte array. + * + * The padding '=' characters at the end are considered optional, but + * if any are present, there must be the correct number of them. + * + * @param input the input array to decode + * @param flags controls certain features of the decoded output. + * Pass {@code DEFAULT} to decode standard Base64. + * + * @throws IllegalArgumentException if the input contains + * incorrect padding + */ + public static byte[] decode(byte[] input, int flags) { + return decode(input, 0, input.length, flags); + } + + /** + * Decode the Base64-encoded data in input and return the data in + * a new byte array. + * + * The padding '=' characters at the end are considered optional, but + * if any are present, there must be the correct number of them. + * + * @param input the data to decode + * @param offset the position within the input array at which to start + * @param len the number of bytes of input to decode + * @param flags controls certain features of the decoded output. + * Pass {@code DEFAULT} to decode standard Base64. + * + * @throws IllegalArgumentException if the input contains + * incorrect padding + */ + public static byte[] decode(byte[] input, int offset, int len, int flags) { + // Allocate space for the most data the input could represent. + // (It could contain less if it contains whitespace, etc.) + DecoderState state = new DecoderState(flags, new byte[len*3/4]); + + if (!decodeInternal(input, offset, len, state, true)) { + throw new IllegalArgumentException("bad base-64"); + } + + // Maybe we got lucky and allocated exactly enough output space. + if (state.op == state.output.length) { + return state.output; + } + + // Need to shorten the array, so allocate a new one of the + // right size and copy. + byte[] temp = new byte[state.op]; + System.arraycopy(state.output, 0, temp, 0, state.op); + return temp; + } + + /* package */ static class DecoderState { + public byte[] output; + public int op; + + public int state; // state number (0 to 6) + public int value; + + final public int[] alphabet; + + public DecoderState(int flags, byte[] output) { + this.output = output; + + alphabet = ((flags & WEB_SAFE) == 0) ? DECODE : DECODE_WEBSAFE; + state = 0; + value = 0; + } + } + + /** + * Decode another block of input data. + * + * @param dstate a DecoderState object whose (caller-provided) + * output array is big enough to hold all the decoded data. + * On return, dstate.op will be set to the length of the + * decoded data. + * @param finish true if this is the final call to decodeInternal + * with the given DecoderState object. Will finalize the + * decoder state and include any final bytes in the output. + * + * @return true if the state machine is still healthy. false if + * bad base-64 data has been detected in the input stream. + */ + + /* package */ static boolean decodeInternal( + byte[] input, int offset, int len, final DecoderState dstate, boolean finish) { + if (dstate.state == 6) return false; + + int state = dstate.state; + int value = dstate.value; + final int[] decode = dstate.alphabet; + final byte[] output = dstate.output; + int op = 0; + + int p = offset; + len += offset; + + while (p < len) { + + // Try the fast path: we're starting a new tuple and the + // next four bytes of the input stream are all data + // bytes. This corresponds to going through states + // 0-1-2-3-0. We expect to use this method for most of + // the data. + // + // If any of the next four bytes of input are non-data + // (whitespace, etc.), value will end up negative. (All + // the non-data values in decode are small negative + // numbers, so shifting any of them up and or'ing them + // together will result in a value with its top bit set.) + // + // You can remove this whole block and the output should + // be the same, just slower. + if (state == 0 && p+4 <= len && + (value = ((decode[input[p] & 0xff] << 18) | + (decode[input[p+1] & 0xff] << 12) | + (decode[input[p+2] & 0xff] << 6) | + (decode[input[p+3] & 0xff]))) >= 0) { + output[op+2] = (byte) value; + output[op+1] = (byte) (value >> 8); + output[op] = (byte) (value >> 16); + op += 3; + p += 4; + continue; + } + + // The fast path isn't available -- either we've read a + // partial tuple, or the next four input bytes aren't all + // data, or whatever. Fall back to the slower state + // machine implementation. + // + // States 0-3 are reading through the next input tuple. + // State 4 is having read one '=' and expecting exactly + // one more. + // State 5 is expecting no more data or padding characters + // in the input. + // State 6 is the error state; an error has been detected + // in the input and no future input can "fix" it. + + int d = decode[input[p++] & 0xff]; + + switch (state) { + case 0: + if (d >= 0) { + value = d; + ++state; + } else if (d != SKIP) { + dstate.state = 6; + return false; + } + break; + + case 1: + if (d >= 0) { + value = (value << 6) | d; + ++state; + } else if (d != SKIP) { + dstate.state = 6; + return false; + } + break; + + case 2: + if (d >= 0) { + value = (value << 6) | d; + ++state; + } else if (d == EQUALS) { + // Emit the last (partial) output tuple; + // expect exactly one more padding character. + output[op++] = (byte) (value >> 4); + state = 4; + } else if (d != SKIP) { + dstate.state = 6; + return false; + } + break; + + case 3: + if (d >= 0) { + // Emit the output triple and return to state 0. + value = (value << 6) | d; + output[op+2] = (byte) value; + output[op+1] = (byte) (value >> 8); + output[op] = (byte) (value >> 16); + op += 3; + state = 0; + } else if (d == EQUALS) { + // Emit the last (partial) output tuple; + // expect no further data or padding characters. + output[op+1] = (byte) (value >> 2); + output[op] = (byte) (value >> 10); + op += 2; + state = 5; + } else if (d != SKIP) { + dstate.state = 6; + return false; + } + break; + + case 4: + if (d == EQUALS) { + ++state; + } else if (d != SKIP) { + dstate.state = 6; + return false; + } + break; + + case 5: + if (d != SKIP) { + dstate.state = 6; + return false; + } + break; + } + } + + if (!finish) { + // We're out of input, but a future call could provide + // more. Return the output we've produced on this call + // and save the current state of the state machine. + dstate.state = state; + dstate.value = value; + dstate.op = op; + return true; + } + + // Done reading input. Now figure out where we are left in + // the state machine and finish up. + + switch (state) { + case 0: + // Output length is a multiple of three. Fine. + break; + case 1: + // Read one extra input byte, which isn't enough to + // make another output byte. Illegal. + dstate.state = 6; + return false; + case 2: + // Read two extra input bytes, enough to emit 1 more + // output byte. Fine. + output[op++] = (byte) (value >> 4); + break; + case 3: + // Read three extra input bytes, enough to emit 2 more + // output bytes. Fine. + output[op+1] = (byte) (value >> 2); + output[op] = (byte) (value >> 10); + op += 2; + break; + case 4: + // Read one padding '=' when we expected 2. Illegal. + dstate.state = 6; + return false; + case 5: + // Read all the padding '='s we expected and no more. + // Fine. + break; + } + + dstate.op = op; + return true; + } + + // -------------------------------------------------------- + // encoding + // -------------------------------------------------------- + + /** + * Emit a new line every this many output tuples. Corresponds to + * a 76-character line length (the maximum allowable according to + * RFC 2045). + */ + private static final int LINE_GROUPS = 19; + + /** + * Lookup table for turning Base64 alphabet positions (6 bits) + * into output bytes. + */ + private static final byte ENCODE[] = { + 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', + 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', + 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', + 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', + 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', + 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', + 'w', 'x', 'y', 'z', '0', '1', '2', '3', + '4', '5', '6', '7', '8', '9', '+', '/', + }; + + /** + * Lookup table for turning Base64 alphabet positions (6 bits) + * into output bytes. + */ + private static final byte ENCODE_WEBSAFE[] = { + 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', + 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', + 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', + 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', + 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', + 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', + 'w', 'x', 'y', 'z', '0', '1', '2', '3', + '4', '5', '6', '7', '8', '9', '-', '_', + }; + + /** + * Base64-encode the given data and return a newly allocated + * String with the result. + * + * @param input the data to encode + * @param flags controls certain features of the encoded output. + * Passing {@code DEFAULT} results in output that + * adheres to RFC 2045. + */ + public static String encodeToString(byte[] input, int flags) { + return new String(encode(input, flags)); + } + + /** + * Base64-encode the given data and return a newly allocated + * String with the result. + * + * @param input the data to encode + * @param offset the position within the input array at which to + * start + * @param len the number of bytes of input to encode + * @param flags controls certain features of the encoded output. + * Passing {@code DEFAULT} results in output that + * adheres to RFC 2045. + */ + public static String encodeToString(byte[] input, int offset, int len, int flags) { + return new String(encode(input, offset, len, flags)); + } + + /** + * Base64-encode the given data and return a newly allocated + * byte[] with the result. + * + * @param input the data to encode + * @param flags controls certain features of the encoded output. + * Passing {@code DEFAULT} results in output that + * adheres to RFC 2045. + */ + public static byte[] encode(byte[] input, int flags) { + return encode(input, 0, input.length, flags); + } + + /** + * Base64-encode the given data and return a newly allocated + * byte[] with the result. + * + * @param input the data to encode + * @param offset the position within the input array at which to + * start + * @param len the number of bytes of input to encode + * @param flags controls certain features of the encoded output. + * Passing {@code DEFAULT} results in output that + * adheres to RFC 2045. + */ + public static byte[] encode(byte[] input, int offset, int len, int flags) { + EncoderState state = new EncoderState(flags, null); + + // Compute the exact length of the array we will produce. + int output_len = len / 3 * 4; + + // Account for the tail of the data and the padding bytes, if any. + if (state.do_padding) { + if (len % 3 > 0) { + output_len += 4; + } + } else { + switch (len % 3) { + case 0: break; + case 1: output_len += 2; break; + case 2: output_len += 3; break; + } + } + + // Account for the newlines, if any. + if (state.do_newline && len > 0) { + output_len += (((len-1) / (3 * LINE_GROUPS)) + 1) * (state.do_cr ? 2 : 1); + } + + state.output = new byte[output_len]; + encodeInternal(input, offset, len, state, true); + + assert state.op == output_len; + + return state.output; + } + + /* package */ static class EncoderState { + public byte[] output; + public int op; + + final public byte[] tail; + public int tailLen; + public int count; + + final public boolean do_padding; + final public boolean do_newline; + final public boolean do_cr; + final public byte[] alphabet; + + public EncoderState(int flags, byte[] output) { + this.output = output; + + do_padding = (flags & NO_PADDING) == 0; + do_newline = (flags & NO_WRAP) == 0; + do_cr = (flags & CRLF) != 0; + alphabet = ((flags & WEB_SAFE) == 0) ? ENCODE : ENCODE_WEBSAFE; + + tail = new byte[2]; + tailLen = 0; + + count = do_newline ? LINE_GROUPS : -1; + } + } + + /** + * Encode another block of input data. + * + * @param estate an EncoderState object whose (caller-provided) + * output array is big enough to hold all the encoded data. + * On return, estate.op will be set to the length of the + * encoded data. + * @param finish true if this is the final call to encodeInternal + * with the given EncoderState object. Will finalize the + * encoder state and include any final bytes in the output. + */ + static void encodeInternal(byte[] input, int offset, int len, + final EncoderState estate, boolean finish) { + final boolean do_cr = estate.do_cr; + final boolean do_newline = estate.do_newline; + final boolean do_padding = estate.do_padding; + final byte[] output = estate.output; + + int op = 0; + + int p = offset; + len += offset; + int v = -1; + int count = estate.count; + + // First we need to concatenate the tail of the previous call + // with any input bytes available now and see if we can empty + // the tail. + + switch (estate.tailLen) { + case 0: + // There was no tail. + break; + + case 1: + if (p+2 <= len) { + // A 1-byte tail with at least 2 bytes of + // input available now. + v = ((estate.tail[0] & 0xff) << 16) | + ((input[p++] & 0xff) << 8) | + (input[p++] & 0xff); + estate.tailLen = 0; + }; + break; + + case 2: + if (p+1 <= len) { + // A 2-byte tail with at least 1 byte of input. + v = ((estate.tail[0] & 0xff) << 16) | + ((estate.tail[1] & 0xff) << 8) | + (input[p++] & 0xff); + estate.tailLen = 0; + } + break; + } + + if (v != -1) { + output[op++] = estate.alphabet[(v >> 18) & 0x3f]; + output[op++] = estate.alphabet[(v >> 12) & 0x3f]; + output[op++] = estate.alphabet[(v >> 6) & 0x3f]; + output[op++] = estate.alphabet[v & 0x3f]; + if (--count == 0) { + if (do_cr) output[op++] = '\r'; + output[op++] = '\n'; + count = LINE_GROUPS; + } + } + + // At this point either there is no tail, or there are fewer + // than 3 bytes of input available. + + // The main loop, turning 3 input bytes into 4 output bytes on + // each iteration. + while (p+3 <= len) { + v = ((input[p++] & 0xff) << 16) | + ((input[p++] & 0xff) << 8) | + (input[p++] & 0xff); + output[op++] = estate.alphabet[(v >> 18) & 0x3f]; + output[op++] = estate.alphabet[(v >> 12) & 0x3f]; + output[op++] = estate.alphabet[(v >> 6) & 0x3f]; + output[op++] = estate.alphabet[v & 0x3f]; + if (--count == 0) { + if (do_cr) output[op++] = '\r'; + output[op++] = '\n'; + count = LINE_GROUPS; + } + } + + if (finish) { + // Finish up the tail of the input. Note that we need to + // consume any bytes in estate.tail before any bytes + // remaining in input; there should be at most two bytes + // total. + + if (p-estate.tailLen == len-1) { + int t = 0; + v = ((estate.tailLen > 0 ? estate.tail[t++] : input[p++]) & 0xff) << 4; + estate.tailLen -= t; + output[op++] = estate.alphabet[(v >> 6) & 0x3f]; + output[op++] = estate.alphabet[v & 0x3f]; + if (do_padding) { + output[op++] = '='; + output[op++] = '='; + } + if (do_newline) { + if (do_cr) output[op++] = '\r'; + output[op++] = '\n'; + } + } else if (p-estate.tailLen == len-2) { + int t = 0; + v = (((estate.tailLen > 1 ? estate.tail[t++] : input[p++]) & 0xff) << 10) | + (((estate.tailLen > 0 ? estate.tail[t++] : input[p++]) & 0xff) << 2); + estate.tailLen -= t; + output[op++] = estate.alphabet[(v >> 12) & 0x3f]; + output[op++] = estate.alphabet[(v >> 6) & 0x3f]; + output[op++] = estate.alphabet[v & 0x3f]; + if (do_padding) { + output[op++] = '='; + } + if (do_newline) { + if (do_cr) output[op++] = '\r'; + output[op++] = '\n'; + } + } else if (do_newline && op > 0 && count != LINE_GROUPS) { + if (do_cr) output[op++] = '\r'; + output[op++] = '\n'; + } + + assert estate.tailLen == 0; + assert p == len; + } else { + // Save the leftovers in tail to be consumed on the next + // call to encodeInternal. + + if (p == len-1) { + estate.tail[estate.tailLen++] = input[p]; + } else if (p == len-2) { + estate.tail[estate.tailLen++] = input[p]; + estate.tail[estate.tailLen++] = input[p+1]; + } + } + + estate.op = op; + estate.count = count; + } + + private Base64() { } // don't instantiate +} diff --git a/core/java/android/util/base64/Base64InputStream.java b/core/java/android/util/base64/Base64InputStream.java new file mode 100644 index 0000000..c0c1636 --- /dev/null +++ b/core/java/android/util/base64/Base64InputStream.java @@ -0,0 +1,169 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package android.util.base64; + +import java.io.FilterInputStream; +import java.io.IOException; +import java.io.InputStream; + +/** + * An OutputStream that does either Base64 encoding or decoding on the + * data written to it, writing the resulting data to another + * OutputStream. + */ +public class Base64InputStream extends FilterInputStream { + private final boolean encode; + private final Base64.EncoderState estate; + private final Base64.DecoderState dstate; + + private static byte[] EMPTY = new byte[0]; + + private static final int BUFFER_SIZE = 2048; + private boolean eof; + private byte[] inputBuffer; + private byte[] outputBuffer; + private int outputStart; + private int outputEnd; + + /** + * An InputStream that performs Base64 decoding on the data read + * from the wrapped stream. + * + * @param in the InputStream to read the source data from + * @param flags bit flags for controlling the decoder; see the + * constants in {@link Base64} + */ + public Base64InputStream(InputStream in, int flags) { + this(in, flags, false); + } + + /** + * Performs Base64 encoding or decoding on the data read from the + * wrapped InputStream. + * + * @param in the InputStream to read the source data from + * @param flags bit flags for controlling the decoder; see the + * constants in {@link Base64} + * @param encode true to encode, false to decode + */ + public Base64InputStream(InputStream in, int flags, boolean encode) { + super(in); + this.encode = encode; + eof = false; + inputBuffer = new byte[BUFFER_SIZE]; + if (encode) { + // len*8/5+10 is an overestimate of the most bytes the + // encoder can produce for len bytes of input. + outputBuffer = new byte[BUFFER_SIZE * 8/5 + 10]; + estate = new Base64.EncoderState(flags, outputBuffer); + dstate = null; + } else { + // len*3/4+10 is an overestimate of the most bytes the + // decoder can produce for len bytes of input. + outputBuffer = new byte[BUFFER_SIZE * 3/4 + 10]; + estate = null; + dstate = new Base64.DecoderState(flags, outputBuffer); + } + outputStart = 0; + outputEnd = 0; + } + + public boolean markSupported() { + return false; + } + + public void mark(int readlimit) { + throw new UnsupportedOperationException(); + } + + public void reset() { + throw new UnsupportedOperationException(); + } + + public void close() throws IOException { + in.close(); + inputBuffer = null; + } + + public int available() { + return outputEnd - outputStart; + } + + public long skip(long n) throws IOException { + if (outputStart >= outputEnd) { + refill(); + } + if (outputStart >= outputEnd) { + return 0; + } + long bytes = Math.min(n, outputEnd-outputStart); + outputStart += bytes; + return bytes; + } + + public int read() throws IOException { + if (outputStart >= outputEnd) { + refill(); + } + if (outputStart >= outputEnd) { + return -1; + } else { + return outputBuffer[outputStart++]; + } + } + + public int read(byte[] b, int off, int len) throws IOException { + if (outputStart >= outputEnd) { + refill(); + } + if (outputStart >= outputEnd) { + return -1; + } + int bytes = Math.min(len, outputEnd-outputStart); + System.arraycopy(outputBuffer, outputStart, b, off, bytes); + outputStart += bytes; + return bytes; + } + + /** + * Read data from the input stream into inputBuffer, then + * decode/encode it into the empty outputBuffer, and reset the + * outputStart and outputEnd pointers. + */ + private void refill() throws IOException { + if (eof) return; + int bytesRead = in.read(inputBuffer); + if (encode) { + if (bytesRead == -1) { + eof = true; + Base64.encodeInternal(EMPTY, 0, 0, estate, true); + } else { + Base64.encodeInternal(inputBuffer, 0, bytesRead, estate, false); + } + outputEnd = estate.op; + } else { + if (bytesRead == -1) { + eof = true; + Base64.decodeInternal(EMPTY, 0, 0, dstate, true); + } else { + Base64.decodeInternal(inputBuffer, 0, bytesRead, dstate, false); + } + outputEnd = dstate.op; + } + outputStart = 0; + } +} diff --git a/core/java/android/util/base64/Base64OutputStream.java b/core/java/android/util/base64/Base64OutputStream.java new file mode 100644 index 0000000..126bde4 --- /dev/null +++ b/core/java/android/util/base64/Base64OutputStream.java @@ -0,0 +1,153 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package android.util.base64; + +import java.io.FilterOutputStream; +import java.io.IOException; +import java.io.OutputStream; + +/** + * An OutputStream that does either Base64 encoding or decoding on the + * data written to it, writing the resulting data to another + * OutputStream. + */ +public class Base64OutputStream extends FilterOutputStream { + private final boolean encode; + private final Base64.EncoderState estate; + private final Base64.DecoderState dstate; + private final int flags; + + private byte[] buffer = null; + private int bpos = 0; + + private static byte[] EMPTY = new byte[0]; + + /** + * Performs Base64 encoding on the data written to the stream, + * writing the encoded data to another OutputStream. + * + * @param out the OutputStream to write the encoded data to + * @param flags bit flags for controlling the encoder; see the + * constants in {@link Base64} + */ + public Base64OutputStream(OutputStream out, int flags) { + this(out, flags, true); + } + + /** + * Performs Base64 encoding or decoding on the data written to the + * stream, writing the encoded/decoded data to another + * OutputStream. + * + * @param out the OutputStream to write the encoded data to + * @param flags bit flags for controlling the encoder; see the + * constants in {@link Base64} + * @param encode true to encode, false to decode + */ + public Base64OutputStream(OutputStream out, int flags, boolean encode) { + super(out); + this.flags = flags; + this.encode = encode; + if (encode) { + estate = new Base64.EncoderState(flags, null); + dstate = null; + } else { + estate = null; + dstate = new Base64.DecoderState(flags, null); + } + } + + public void write(int b) throws IOException { + // To avoid invoking the encoder/decoder routines for single + // bytes, we buffer up calls to write(int) in an internal + // byte array to transform them into writes of decently-sized + // arrays. + + if (buffer == null) { + buffer = new byte[1024]; + } + if (bpos >= buffer.length) { + // internal buffer full; write it out. + internalWrite(buffer, 0, bpos, false); + bpos = 0; + } + buffer[bpos++] = (byte) b; + } + + /** + * Flush any buffered data from calls to write(int). Needed + * before doing a write(byte[], int, int) or a close(). + */ + private void flushBuffer() throws IOException { + if (bpos > 0) { + internalWrite(buffer, 0, bpos, false); + bpos = 0; + } + } + + public void write(byte[] b, int off, int len) throws IOException { + if (len <= 0) return; + flushBuffer(); + internalWrite(b, off, len, false); + } + + public void close() throws IOException { + flushBuffer(); + internalWrite(EMPTY, 0, 0, true); + if ((flags & Base64.NO_CLOSE) == 0) { + out.close(); + } else { + out.flush(); + } + } + + /** + * Write the given bytes to the encoder/decoder. + * + * @param finish true if this is the last batch of input, to cause + * encoder/decoder state to be finalized. + */ + private void internalWrite(byte[] b, int off, int len, boolean finish) throws IOException { + if (encode) { + // len*8/5+10 is an overestimate of the most bytes the + // encoder can produce for len bytes of input. + estate.output = embiggen(estate.output, len*8/5+10); + Base64.encodeInternal(b, off, len, estate, finish); + out.write(estate.output, 0, estate.op); + } else { + // len*3/4+10 is an overestimate of the most bytes the + // decoder can produce for len bytes of input. + dstate.output = embiggen(dstate.output, len*3/4+10); + if (!Base64.decodeInternal(b, off, len, dstate, finish)) { + throw new IOException("bad base-64"); + } + out.write(dstate.output, 0, dstate.op); + } + } + + /** + * If b.length is at least len, return b. Otherwise return a new + * byte array of length len. + */ + private byte[] embiggen(byte[] b, int len) { + if (b == null || b.length < len) { + return new byte[len]; + } else { + return b; + } + } +} |