org.apache.trevni.InputBuffer Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.trevni;
import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
/** Used to read values. */
class InputBuffer {
private Input in;
private long inLength;
private long offset; // pos of next read from in
private byte[] buf; // data from input
private int pos; // position within buffer
private int limit; // end of valid buffer data
private CharsetDecoder utf8 = Charset.forName("UTF-8").newDecoder();
private int bitCount; // position in booleans
private int runLength; // length of run
private int runValue; // value of run
public InputBuffer(Input in) throws IOException { this(in, 0); }
public InputBuffer(Input in, long position) throws IOException {
this.in = in;
this.inLength = in.length();
this.offset = position;
if (in instanceof InputBytes) { // use buffer directly
this.buf = ((InputBytes)in).getBuffer();
this.limit = (int)in.length();
this.offset = limit;
this.pos = (int)position;
} else { // create new buffer
this.buf = new byte[8192]; // big enough for primitives
}
}
public void seek(long position) throws IOException {
runLength = 0;
if (position >= (offset-limit) && position <= offset) {
pos = (int)(limit - (offset - position)); // seek in buffer;
return;
}
pos = 0;
limit = 0;
offset = position;
}
public long tell() { return (offset-limit)+pos; }
public long length() { return inLength; }
public T readValue(ValueType type) throws IOException {
switch (type) {
case NULL:
return (T)null;
case BOOLEAN:
return (T)Boolean.valueOf(readBoolean());
case INT:
return (T)Integer.valueOf(readInt());
case LONG:
return (T)Long.valueOf(readLong());
case FIXED32:
return (T)Integer.valueOf(readFixed32());
case FIXED64:
return (T)Long.valueOf(readFixed64());
case FLOAT:
return (T)Float.valueOf(readFloat());
case DOUBLE:
return (T)Double.valueOf(readDouble());
case STRING:
return (T)readString();
case BYTES:
return (T)readBytes(null);
default:
throw new TrevniRuntimeException("Unknown value type: "+type);
}
}
public void skipValue(ValueType type) throws IOException {
switch (type) {
case NULL:
break;
case BOOLEAN:
readBoolean(); break;
case INT:
readInt(); break;
case LONG:
readLong(); break;
case FIXED32:
case FLOAT:
skip(4); break;
case FIXED64:
case DOUBLE:
skip(8); break;
case STRING:
case BYTES:
skipBytes(); break;
default:
throw new TrevniRuntimeException("Unknown value type: "+type);
}
}
public boolean readBoolean() throws IOException {
if (bitCount == 0)
read();
int bits = buf[pos-1] & 0xff;
int bit = (bits >> bitCount) & 1;
bitCount++;
if (bitCount == 8)
bitCount = 0;
return bit == 0 ? false : true;
}
public int readLength() throws IOException {
bitCount = 0;
if (runLength > 0) {
runLength--; // in run
return runValue;
}
int length = readInt();
if (length >= 0) // not a run
return length;
runLength = (1-length)>>>1; // start of run
runValue = (length+1) & 1;
return runValue;
}
public int readInt() throws IOException {
if ((limit - pos) < 5) { // maybe not in buffer
int b = read();
int n = b & 0x7f;
for (int shift = 7; b > 0x7f; shift += 7) {
b = read();
n ^= (b & 0x7f) << shift;
}
return (n >>> 1) ^ -(n & 1); // back to two's-complement
}
int len = 1;
int b = buf[pos] & 0xff;
int n = b & 0x7f;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
n ^= (b & 0x7f) << 7;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
n ^= (b & 0x7f) << 14;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
n ^= (b & 0x7f) << 21;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
n ^= (b & 0x7f) << 28;
if (b > 0x7f) {
throw new IOException("Invalid int encoding");
}
}
}
}
}
pos += len;
if (pos > limit)
throw new EOFException();
return (n >>> 1) ^ -(n & 1); // back to two's-complement
}
public long readLong() throws IOException {
if ((limit - pos) < 10) { // maybe not in buffer
int b = read();
long n = b & 0x7f;
for (int shift = 7; b > 0x7f; shift += 7) {
b = read();
n ^= (b & 0x7fL) << shift;
}
return (n >>> 1) ^ -(n & 1); // back to two's-complement
}
int b = buf[pos++] & 0xff;
int n = b & 0x7f;
long l;
if (b > 0x7f) {
b = buf[pos++] & 0xff;
n ^= (b & 0x7f) << 7;
if (b > 0x7f) {
b = buf[pos++] & 0xff;
n ^= (b & 0x7f) << 14;
if (b > 0x7f) {
b = buf[pos++] & 0xff;
n ^= (b & 0x7f) << 21;
if (b > 0x7f) {
// only the low 28 bits can be set, so this won't carry
// the sign bit to the long
l = innerLongDecode((long)n);
} else {
l = n;
}
} else {
l = n;
}
} else {
l = n;
}
} else {
l = n;
}
if (pos > limit) {
throw new EOFException();
}
return (l >>> 1) ^ -(l & 1); // back to two's-complement
}
// splitting readLong up makes it faster because of the JVM does more
// optimizations on small methods
private long innerLongDecode(long l) throws IOException {
int len = 1;
int b = buf[pos] & 0xff;
l ^= (b & 0x7fL) << 28;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
l ^= (b & 0x7fL) << 35;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
l ^= (b & 0x7fL) << 42;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
l ^= (b & 0x7fL) << 49;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
l ^= (b & 0x7fL) << 56;
if (b > 0x7f) {
b = buf[pos + len++] & 0xff;
l ^= (b & 0x7fL) << 63;
if (b > 0x7f) {
throw new IOException("Invalid long encoding");
}
}
}
}
}
}
pos += len;
return l;
}
public float readFloat() throws IOException {
return Float.intBitsToFloat(readFixed32());
}
public int readFixed32() throws IOException {
if ((limit - pos) < 4) // maybe not in buffer
return read() | (read() << 8) | (read() << 16) | (read() << 24);
int len = 1;
int n = (buf[pos] & 0xff) | ((buf[pos + len++] & 0xff) << 8)
| ((buf[pos + len++] & 0xff) << 16) | ((buf[pos + len++] & 0xff) << 24);
if ((pos + 4) > limit)
throw new EOFException();
pos += 4;
return n;
}
public double readDouble() throws IOException {
return Double.longBitsToDouble(readFixed64());
}
public long readFixed64() throws IOException {
return (readFixed32() & 0xFFFFFFFFL) | (((long)readFixed32()) << 32);
}
public String readString() throws IOException {
int length = readInt();
if (length <= (limit - pos)) { // in buffer
String result = utf8.decode(ByteBuffer.wrap(buf, pos, length)).toString();
pos += length;
return result;
}
byte[] bytes = new byte[length];
readFully(bytes, 0, length);
return utf8.decode(ByteBuffer.wrap(bytes, 0, length)).toString();
}
public byte[] readBytes() throws IOException {
byte[] result = new byte[readInt()];
readFully(result);
return result;
}
public ByteBuffer readBytes(ByteBuffer old) throws IOException {
int length = readInt();
ByteBuffer result;
if (old != null && length <= old.capacity()) {
result = old;
result.clear();
} else {
result = ByteBuffer.allocate(length);
}
readFully(result.array(), result.position(), length);
result.limit(length);
return result;
}
public void skipBytes() throws IOException {
skip(readInt());
}
private void skip(long length) throws IOException {
seek(tell()+length);
}
public int read() throws IOException {
if (pos >= limit) {
limit = readInput(buf, 0, buf.length);
pos = 0;
}
return buf[pos++] & 0xFF;
}
public void readFully(byte[] bytes) throws IOException {
readFully(bytes, 0, bytes.length);
}
public void readFully(byte[] bytes, int start, int len) throws IOException {
int buffered = limit - pos;
if (len > buffered) { // buffer is insufficient
System.arraycopy(buf, pos, bytes, start, buffered); // consume buffer
start += buffered;
len -= buffered;
pos += buffered;
if (len > buf.length) { // bigger than buffer
do {
int read = readInput(bytes, start, len); // read directly into result
len -= read;
start += read;
} while (len > 0);
return;
}
limit = readInput(buf, 0, buf.length); // refill buffer
pos = 0;
}
System.arraycopy(buf, pos, bytes, start, len); // copy from buffer
pos += len;
}
private int readInput(byte[] b, int start, int len) throws IOException {
int read = in.read(offset, b, start, len);
if (read < 0) throw new EOFException();
offset += read;
return read;
}
}
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