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Diffstat (limited to 'java/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java')
-rw-r--r-- | java/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java | 624 |
1 files changed, 624 insertions, 0 deletions
diff --git a/java/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java b/java/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java new file mode 100644 index 0000000..ed38788 --- /dev/null +++ b/java/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java @@ -0,0 +1,624 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2013 Google Inc. All rights reserved. +// http://code.google.com/p/protobuf/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +package com.google.protobuf.nano; + +import java.io.IOException; + +/** + * Reads and decodes protocol message fields. + * + * This class contains two kinds of methods: methods that read specific + * protocol message constructs and field types (e.g. {@link #readTag()} and + * {@link #readInt32()}) and methods that read low-level values (e.g. + * {@link #readRawVarint32()} and {@link #readRawBytes}). If you are reading + * encoded protocol messages, you should use the former methods, but if you are + * reading some other format of your own design, use the latter. + * + * @author kenton@google.com Kenton Varda + */ +public final class CodedInputByteBufferNano { + /** + * Create a new CodedInputStream wrapping the given byte array. + */ + public static CodedInputByteBufferNano newInstance(final byte[] buf) { + return newInstance(buf, 0, buf.length); + } + + /** + * Create a new CodedInputStream wrapping the given byte array slice. + */ + public static CodedInputByteBufferNano newInstance(final byte[] buf, final int off, + final int len) { + return new CodedInputByteBufferNano(buf, off, len); + } + + // ----------------------------------------------------------------- + + /** + * Attempt to read a field tag, returning zero if we have reached EOF. + * Protocol message parsers use this to read tags, since a protocol message + * may legally end wherever a tag occurs, and zero is not a valid tag number. + */ + public int readTag() throws IOException { + if (isAtEnd()) { + lastTag = 0; + return 0; + } + + lastTag = readRawVarint32(); + if (lastTag == 0) { + // If we actually read zero, that's not a valid tag. + throw InvalidProtocolBufferNanoException.invalidTag(); + } + return lastTag; + } + + /** + * Verifies that the last call to readTag() returned the given tag value. + * This is used to verify that a nested group ended with the correct + * end tag. + * + * @throws InvalidProtocolBufferNanoException {@code value} does not match the + * last tag. + */ + public void checkLastTagWas(final int value) + throws InvalidProtocolBufferNanoException { + if (lastTag != value) { + throw InvalidProtocolBufferNanoException.invalidEndTag(); + } + } + + /** + * Reads and discards a single field, given its tag value. + * + * @return {@code false} if the tag is an endgroup tag, in which case + * nothing is skipped. Otherwise, returns {@code true}. + */ + public boolean skipField(final int tag) throws IOException { + switch (WireFormatNano.getTagWireType(tag)) { + case WireFormatNano.WIRETYPE_VARINT: + readInt32(); + return true; + case WireFormatNano.WIRETYPE_FIXED64: + readRawLittleEndian64(); + return true; + case WireFormatNano.WIRETYPE_LENGTH_DELIMITED: + skipRawBytes(readRawVarint32()); + return true; + case WireFormatNano.WIRETYPE_START_GROUP: + skipMessage(); + checkLastTagWas( + WireFormatNano.makeTag(WireFormatNano.getTagFieldNumber(tag), + WireFormatNano.WIRETYPE_END_GROUP)); + return true; + case WireFormatNano.WIRETYPE_END_GROUP: + return false; + case WireFormatNano.WIRETYPE_FIXED32: + readRawLittleEndian32(); + return true; + default: + throw InvalidProtocolBufferNanoException.invalidWireType(); + } + } + + /** + * Reads and discards an entire message. This will read either until EOF + * or until an endgroup tag, whichever comes first. + */ + public void skipMessage() throws IOException { + while (true) { + final int tag = readTag(); + if (tag == 0 || !skipField(tag)) { + return; + } + } + } + + // ----------------------------------------------------------------- + + /** Read a {@code double} field value from the stream. */ + public double readDouble() throws IOException { + return Double.longBitsToDouble(readRawLittleEndian64()); + } + + /** Read a {@code float} field value from the stream. */ + public float readFloat() throws IOException { + return Float.intBitsToFloat(readRawLittleEndian32()); + } + + /** Read a {@code uint64} field value from the stream. */ + public long readUInt64() throws IOException { + return readRawVarint64(); + } + + /** Read an {@code int64} field value from the stream. */ + public long readInt64() throws IOException { + return readRawVarint64(); + } + + /** Read an {@code int32} field value from the stream. */ + public int readInt32() throws IOException { + return readRawVarint32(); + } + + /** Read a {@code fixed64} field value from the stream. */ + public long readFixed64() throws IOException { + return readRawLittleEndian64(); + } + + /** Read a {@code fixed32} field value from the stream. */ + public int readFixed32() throws IOException { + return readRawLittleEndian32(); + } + + /** Read a {@code bool} field value from the stream. */ + public boolean readBool() throws IOException { + return readRawVarint32() != 0; + } + + /** Read a {@code string} field value from the stream. */ + public String readString() throws IOException { + final int size = readRawVarint32(); + if (size <= (bufferSize - bufferPos) && size > 0) { + // Fast path: We already have the bytes in a contiguous buffer, so + // just copy directly from it. + final String result = new String(buffer, bufferPos, size, "UTF-8"); + bufferPos += size; + return result; + } else { + // Slow path: Build a byte array first then copy it. + return new String(readRawBytes(size), "UTF-8"); + } + } + + /** Read a {@code group} field value from the stream. */ + public void readGroup(final MessageNano msg, final int fieldNumber) + throws IOException { + if (recursionDepth >= recursionLimit) { + throw InvalidProtocolBufferNanoException.recursionLimitExceeded(); + } + ++recursionDepth; + msg.mergeFrom(this); + checkLastTagWas( + WireFormatNano.makeTag(fieldNumber, WireFormatNano.WIRETYPE_END_GROUP)); + --recursionDepth; + } + + public void readMessage(final MessageNano msg) + throws IOException { + final int length = readRawVarint32(); + if (recursionDepth >= recursionLimit) { + throw InvalidProtocolBufferNanoException.recursionLimitExceeded(); + } + final int oldLimit = pushLimit(length); + ++recursionDepth; + msg.mergeFrom(this); + checkLastTagWas(0); + --recursionDepth; + popLimit(oldLimit); + } + + /** Read a {@code bytes} field value from the stream. */ + public byte[] readBytes() throws IOException { + final int size = readRawVarint32(); + if (size <= (bufferSize - bufferPos) && size > 0) { + // Fast path: We already have the bytes in a contiguous buffer, so + // just copy directly from it. + final byte[] result = new byte[size]; + System.arraycopy(buffer, bufferPos, result, 0, size); + bufferPos += size; + return result; + } else { + // Slow path: Build a byte array first then copy it. + return readRawBytes(size); + } + } + + /** Read a {@code uint32} field value from the stream. */ + public int readUInt32() throws IOException { + return readRawVarint32(); + } + + /** + * Read an enum field value from the stream. Caller is responsible + * for converting the numeric value to an actual enum. + */ + public int readEnum() throws IOException { + return readRawVarint32(); + } + + /** Read an {@code sfixed32} field value from the stream. */ + public int readSFixed32() throws IOException { + return readRawLittleEndian32(); + } + + /** Read an {@code sfixed64} field value from the stream. */ + public long readSFixed64() throws IOException { + return readRawLittleEndian64(); + } + + /** Read an {@code sint32} field value from the stream. */ + public int readSInt32() throws IOException { + return decodeZigZag32(readRawVarint32()); + } + + /** Read an {@code sint64} field value from the stream. */ + public long readSInt64() throws IOException { + return decodeZigZag64(readRawVarint64()); + } + + // ================================================================= + + /** + * Read a raw Varint from the stream. If larger than 32 bits, discard the + * upper bits. + */ + public int readRawVarint32() throws IOException { + byte tmp = readRawByte(); + if (tmp >= 0) { + return tmp; + } + int result = tmp & 0x7f; + if ((tmp = readRawByte()) >= 0) { + result |= tmp << 7; + } else { + result |= (tmp & 0x7f) << 7; + if ((tmp = readRawByte()) >= 0) { + result |= tmp << 14; + } else { + result |= (tmp & 0x7f) << 14; + if ((tmp = readRawByte()) >= 0) { + result |= tmp << 21; + } else { + result |= (tmp & 0x7f) << 21; + result |= (tmp = readRawByte()) << 28; + if (tmp < 0) { + // Discard upper 32 bits. + for (int i = 0; i < 5; i++) { + if (readRawByte() >= 0) { + return result; + } + } + throw InvalidProtocolBufferNanoException.malformedVarint(); + } + } + } + } + return result; + } + + /** Read a raw Varint from the stream. */ + public long readRawVarint64() throws IOException { + int shift = 0; + long result = 0; + while (shift < 64) { + final byte b = readRawByte(); + result |= (long)(b & 0x7F) << shift; + if ((b & 0x80) == 0) { + return result; + } + shift += 7; + } + throw InvalidProtocolBufferNanoException.malformedVarint(); + } + + /** Read a 32-bit little-endian integer from the stream. */ + public int readRawLittleEndian32() throws IOException { + final byte b1 = readRawByte(); + final byte b2 = readRawByte(); + final byte b3 = readRawByte(); + final byte b4 = readRawByte(); + return ((b1 & 0xff) ) | + ((b2 & 0xff) << 8) | + ((b3 & 0xff) << 16) | + ((b4 & 0xff) << 24); + } + + /** Read a 64-bit little-endian integer from the stream. */ + public long readRawLittleEndian64() throws IOException { + final byte b1 = readRawByte(); + final byte b2 = readRawByte(); + final byte b3 = readRawByte(); + final byte b4 = readRawByte(); + final byte b5 = readRawByte(); + final byte b6 = readRawByte(); + final byte b7 = readRawByte(); + final byte b8 = readRawByte(); + return (((long)b1 & 0xff) ) | + (((long)b2 & 0xff) << 8) | + (((long)b3 & 0xff) << 16) | + (((long)b4 & 0xff) << 24) | + (((long)b5 & 0xff) << 32) | + (((long)b6 & 0xff) << 40) | + (((long)b7 & 0xff) << 48) | + (((long)b8 & 0xff) << 56); + } + + /** + * Decode a ZigZag-encoded 32-bit value. ZigZag encodes signed integers + * into values that can be efficiently encoded with varint. (Otherwise, + * negative values must be sign-extended to 64 bits to be varint encoded, + * thus always taking 10 bytes on the wire.) + * + * @param n An unsigned 32-bit integer, stored in a signed int because + * Java has no explicit unsigned support. + * @return A signed 32-bit integer. + */ + public static int decodeZigZag32(final int n) { + return (n >>> 1) ^ -(n & 1); + } + + /** + * Decode a ZigZag-encoded 64-bit value. ZigZag encodes signed integers + * into values that can be efficiently encoded with varint. (Otherwise, + * negative values must be sign-extended to 64 bits to be varint encoded, + * thus always taking 10 bytes on the wire.) + * + * @param n An unsigned 64-bit integer, stored in a signed int because + * Java has no explicit unsigned support. + * @return A signed 64-bit integer. + */ + public static long decodeZigZag64(final long n) { + return (n >>> 1) ^ -(n & 1); + } + + // ----------------------------------------------------------------- + + private final byte[] buffer; + private int bufferStart; + private int bufferSize; + private int bufferSizeAfterLimit; + private int bufferPos; + private int lastTag; + + /** The absolute position of the end of the current message. */ + private int currentLimit = Integer.MAX_VALUE; + + /** See setRecursionLimit() */ + private int recursionDepth; + private int recursionLimit = DEFAULT_RECURSION_LIMIT; + + /** See setSizeLimit() */ + private int sizeLimit = DEFAULT_SIZE_LIMIT; + + private static final int DEFAULT_RECURSION_LIMIT = 64; + private static final int DEFAULT_SIZE_LIMIT = 64 << 20; // 64MB + + private CodedInputByteBufferNano(final byte[] buffer, final int off, final int len) { + this.buffer = buffer; + bufferStart = off; + bufferSize = off + len; + bufferPos = off; + } + + /** + * Set the maximum message recursion depth. In order to prevent malicious + * messages from causing stack overflows, {@code CodedInputStream} limits + * how deeply messages may be nested. The default limit is 64. + * + * @return the old limit. + */ + public int setRecursionLimit(final int limit) { + if (limit < 0) { + throw new IllegalArgumentException( + "Recursion limit cannot be negative: " + limit); + } + final int oldLimit = recursionLimit; + recursionLimit = limit; + return oldLimit; + } + + /** + * Set the maximum message size. In order to prevent malicious + * messages from exhausting memory or causing integer overflows, + * {@code CodedInputStream} limits how large a message may be. + * The default limit is 64MB. You should set this limit as small + * as you can without harming your app's functionality. Note that + * size limits only apply when reading from an {@code InputStream}, not + * when constructed around a raw byte array. + * <p> + * If you want to read several messages from a single CodedInputStream, you + * could call {@link #resetSizeCounter()} after each one to avoid hitting the + * size limit. + * + * @return the old limit. + */ + public int setSizeLimit(final int limit) { + if (limit < 0) { + throw new IllegalArgumentException( + "Size limit cannot be negative: " + limit); + } + final int oldLimit = sizeLimit; + sizeLimit = limit; + return oldLimit; + } + + /** + * Resets the current size counter to zero (see {@link #setSizeLimit(int)}). + */ + public void resetSizeCounter() { + } + + /** + * Sets {@code currentLimit} to (current position) + {@code byteLimit}. This + * is called when descending into a length-delimited embedded message. + * + * @return the old limit. + */ + public int pushLimit(int byteLimit) throws InvalidProtocolBufferNanoException { + if (byteLimit < 0) { + throw InvalidProtocolBufferNanoException.negativeSize(); + } + byteLimit += bufferPos; + final int oldLimit = currentLimit; + if (byteLimit > oldLimit) { + throw InvalidProtocolBufferNanoException.truncatedMessage(); + } + currentLimit = byteLimit; + + recomputeBufferSizeAfterLimit(); + + return oldLimit; + } + + private void recomputeBufferSizeAfterLimit() { + bufferSize += bufferSizeAfterLimit; + final int bufferEnd = bufferSize; + if (bufferEnd > currentLimit) { + // Limit is in current buffer. + bufferSizeAfterLimit = bufferEnd - currentLimit; + bufferSize -= bufferSizeAfterLimit; + } else { + bufferSizeAfterLimit = 0; + } + } + + /** + * Discards the current limit, returning to the previous limit. + * + * @param oldLimit The old limit, as returned by {@code pushLimit}. + */ + public void popLimit(final int oldLimit) { + currentLimit = oldLimit; + recomputeBufferSizeAfterLimit(); + } + + /** + * Returns the number of bytes to be read before the current limit. + * If no limit is set, returns -1. + */ + public int getBytesUntilLimit() { + if (currentLimit == Integer.MAX_VALUE) { + return -1; + } + + final int currentAbsolutePosition = bufferPos; + return currentLimit - currentAbsolutePosition; + } + + /** + * Returns true if the stream has reached the end of the input. This is the + * case if either the end of the underlying input source has been reached or + * if the stream has reached a limit created using {@link #pushLimit(int)}. + */ + public boolean isAtEnd() { + return bufferPos == bufferSize; + } + + /** + * Get current position in buffer relative to beginning offset. + */ + public int getPosition() { + return bufferPos - bufferStart; + } + + /** + * Rewind to previous position. Cannot go forward. + */ + public void rewindToPosition(int position) { + if (position > bufferPos - bufferStart) { + throw new IllegalArgumentException( + "Position " + position + " is beyond current " + (bufferPos - bufferStart)); + } + if (position < 0) { + throw new IllegalArgumentException("Bad position " + position); + } + bufferPos = bufferStart + position; + } + + /** + * Read one byte from the input. + * + * @throws InvalidProtocolBufferNanoException The end of the stream or the current + * limit was reached. + */ + public byte readRawByte() throws IOException { + if (bufferPos == bufferSize) { + throw InvalidProtocolBufferNanoException.truncatedMessage(); + } + return buffer[bufferPos++]; + } + + /** + * Read a fixed size of bytes from the input. + * + * @throws InvalidProtocolBufferNanoException The end of the stream or the current + * limit was reached. + */ + public byte[] readRawBytes(final int size) throws IOException { + if (size < 0) { + throw InvalidProtocolBufferNanoException.negativeSize(); + } + + if (bufferPos + size > currentLimit) { + // Read to the end of the stream anyway. + skipRawBytes(currentLimit - bufferPos); + // Then fail. + throw InvalidProtocolBufferNanoException.truncatedMessage(); + } + + if (size <= bufferSize - bufferPos) { + // We have all the bytes we need already. + final byte[] bytes = new byte[size]; + System.arraycopy(buffer, bufferPos, bytes, 0, size); + bufferPos += size; + return bytes; + } else { + throw InvalidProtocolBufferNanoException.truncatedMessage(); + } + } + + /** + * Reads and discards {@code size} bytes. + * + * @throws InvalidProtocolBufferNanoException The end of the stream or the current + * limit was reached. + */ + public void skipRawBytes(final int size) throws IOException { + if (size < 0) { + throw InvalidProtocolBufferNanoException.negativeSize(); + } + + if (bufferPos + size > currentLimit) { + // Read to the end of the stream anyway. + skipRawBytes(currentLimit - bufferPos); + // Then fail. + throw InvalidProtocolBufferNanoException.truncatedMessage(); + } + + if (size <= bufferSize - bufferPos) { + // We have all the bytes we need already. + bufferPos += size; + } else { + throw InvalidProtocolBufferNanoException.truncatedMessage(); + } + } +} |