diff options
Diffstat (limited to 'mobile/android/thirdparty/com/squareup/picasso/MarkableInputStream.java')
-rw-r--r-- | mobile/android/thirdparty/com/squareup/picasso/MarkableInputStream.java | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/mobile/android/thirdparty/com/squareup/picasso/MarkableInputStream.java b/mobile/android/thirdparty/com/squareup/picasso/MarkableInputStream.java new file mode 100644 index 000000000..17043a1b0 --- /dev/null +++ b/mobile/android/thirdparty/com/squareup/picasso/MarkableInputStream.java @@ -0,0 +1,157 @@ +/* + * Copyright (C) 2013 Square, Inc. + * + * 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 com.squareup.picasso; + +import java.io.BufferedInputStream; +import java.io.IOException; +import java.io.InputStream; + +/** + * An input stream wrapper that supports unlimited independent cursors for + * marking and resetting. Each cursor is a token, and it's the caller's + * responsibility to keep track of these. + */ +final class MarkableInputStream extends InputStream { + private final InputStream in; + + private long offset; + private long reset; + private long limit; + + private long defaultMark = -1; + + public MarkableInputStream(InputStream in) { + if (!in.markSupported()) { + in = new BufferedInputStream(in); + } + this.in = in; + } + + /** Marks this place in the stream so we can reset back to it later. */ + @Override public void mark(int readLimit) { + defaultMark = savePosition(readLimit); + } + + /** + * Returns an opaque token representing the current position in the stream. + * Call {@link #reset(long)} to return to this position in the stream later. + * It is an error to call {@link #reset(long)} after consuming more than + * {@code readLimit} bytes from this stream. + */ + public long savePosition(int readLimit) { + long offsetLimit = offset + readLimit; + if (limit < offsetLimit) { + setLimit(offsetLimit); + } + return offset; + } + + /** + * Makes sure that the underlying stream can backtrack the full range from + * {@code reset} thru {@code limit}. Since we can't call {@code mark()} + * without also adjusting the reset-to-position on the underlying stream this + * method resets first and then marks the union of the two byte ranges. On + * buffered streams this additional cursor motion shouldn't result in any + * additional I/O. + */ + private void setLimit(long limit) { + try { + if (reset < offset && offset <= this.limit) { + in.reset(); + in.mark((int) (limit - reset)); + skip(reset, offset); + } else { + reset = offset; + in.mark((int) (limit - offset)); + } + this.limit = limit; + } catch (IOException e) { + throw new IllegalStateException("Unable to mark: " + e); + } + } + + /** Resets the stream to the most recent {@link #mark mark}. */ + @Override public void reset() throws IOException { + reset(defaultMark); + } + + /** Resets the stream to the position recorded by {@code token}. */ + public void reset(long token) throws IOException { + if (offset > limit || token < reset) { + throw new IOException("Cannot reset"); + } + in.reset(); + skip(reset, token); + offset = token; + } + + /** Skips {@code target - current} bytes and returns. */ + private void skip(long current, long target) throws IOException { + while (current < target) { + long skipped = in.skip(target - current); + if (skipped == 0) { + if (read() == -1) { + break; // EOF + } else { + skipped = 1; + } + } + current += skipped; + } + } + + @Override public int read() throws IOException { + int result = in.read(); + if (result != -1) { + offset++; + } + return result; + } + + @Override public int read(byte[] buffer) throws IOException { + int count = in.read(buffer); + if (count != -1) { + offset += count; + } + return count; + } + + @Override public int read(byte[] buffer, int offset, int length) throws IOException { + int count = in.read(buffer, offset, length); + if (count != -1) { + this.offset += count; + } + return count; + } + + @Override public long skip(long byteCount) throws IOException { + long skipped = in.skip(byteCount); + offset += skipped; + return skipped; + } + + @Override public int available() throws IOException { + return in.available(); + } + + @Override public void close() throws IOException { + in.close(); + } + + @Override public boolean markSupported() { + return in.markSupported(); + } +} |