com.yahoo.slime.BufferedInput Maven / Gradle / Ivy
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.slime;
final class BufferedInput {
private final byte[] source;
private final int end;
private final int start;
private int position;
private String failReason;
private int failPos;
void fail(String reason) {
if (failed()) {
return;
}
failReason = reason;
failPos = position;
position = end;
}
BufferedInput(byte[] bytes) {
this(bytes, 0, bytes.length);
}
BufferedInput(byte[] bytes, int offset, int length) {
this.source = bytes;
this.start = offset;
position = offset;
this.end = offset + length;
}
byte getByte() {
if (position == end) {
fail("underflow");
return 0;
}
return source[position++];
}
boolean failed() {
return failReason != null;
}
boolean eof() {
return this.position == this.end;
}
String getErrorMessage() {
return failReason;
}
int getConsumedSize() {
return failed() ? 0 : position - start;
}
byte[] getOffending() {
byte[] ret = new byte[failPos-start];
System.arraycopy(source, start, ret, 0, failPos-start);
return ret;
}
byte[] getBacking() { return source; }
int getPosition() { return position; }
void skip(int size) {
if (position + size > end) {
fail("underflow");
} else {
position += size;
}
}
byte[] getBytes(int size) {
if (position + size > end) {
fail("underflow");
return new byte[0];
}
byte[] ret = new byte[size];
for (int i = 0; i < size; i++) {
ret[i] = source[position++];
}
return ret;
}
int read_cmpr_int() {
long next = getByte();
long value = (next & 0x7f);
int shift = 7;
while (shift < 32 && (next & 0x80) != 0) {
next = getByte();
value |= ((next & 0x7f) << shift);
shift += 7;
}
if (value > 0x7fff_ffffL) {
fail("compressed int overflow");
value = 0;
}
return (int)value;
}
int skip_cmpr_int() {
int extBits = 0;
while ((getByte() & 0x80) != 0) {
++extBits;
}
return extBits;
}
int read_size(int meta) {
return (meta == 0) ? read_cmpr_int() : (meta - 1);
}
}