// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// 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;
/**
* Provide text format escaping support for proto2 instances.
*/
final class TextFormatEscaper {
private TextFormatEscaper() {}
private interface ByteSequence {
int size();
byte byteAt(int offset);
}
/**
* Escapes bytes in the format used in protocol buffer text format, which
* is the same as the format used for C string literals. All bytes
* that are not printable 7-bit ASCII characters are escaped, as well as
* backslash, single-quote, and double-quote characters. Characters for
* which no defined short-hand escape sequence is defined will be escaped
* using 3-digit octal sequences.
*/
static String escapeBytes(final ByteSequence input) {
final StringBuilder builder = new StringBuilder(input.size());
for (int i = 0; i < input.size(); i++) {
final byte b = input.byteAt(i);
switch (b) {
// Java does not recognize \a or \v, apparently.
case 0x07: builder.append("\\a"); break;
case '\b': builder.append("\\b"); break;
case '\f': builder.append("\\f"); break;
case '\n': builder.append("\\n"); break;
case '\r': builder.append("\\r"); break;
case '\t': builder.append("\\t"); break;
case 0x0b: builder.append("\\v"); break;
case '\\': builder.append("\\\\"); break;
case '\'': builder.append("\\\'"); break;
case '"' : builder.append("\\\""); break;
default:
// Only ASCII characters between 0x20 (space) and 0x7e (tilde) are
// printable. Other byte values must be escaped.
if (b >= 0x20 && b <= 0x7e) {
builder.append((char) b);
} else {
builder.append('\\');
builder.append((char) ('0' + ((b >>> 6) & 3)));
builder.append((char) ('0' + ((b >>> 3) & 7)));
builder.append((char) ('0' + (b & 7)));
}
break;
}
}
return builder.toString();
}
/**
* Escapes bytes in the format used in protocol buffer text format, which
* is the same as the format used for C string literals. All bytes
* that are not printable 7-bit ASCII characters are escaped, as well as
* backslash, single-quote, and double-quote characters. Characters for
* which no defined short-hand escape sequence is defined will be escaped
* using 3-digit octal sequences.
*/
static String escapeBytes(final ByteString input) {
return escapeBytes(new ByteSequence() {
@Override
public int size() {
return input.size();
}
@Override
public byte byteAt(int offset) {
return input.byteAt(offset);
}
});
}
/**
* Like {@link #escapeBytes(ByteString)}, but used for byte array.
*/
static String escapeBytes(final byte[] input) {
return escapeBytes(new ByteSequence() {
@Override
public int size() {
return input.length;
}
@Override
public byte byteAt(int offset) {
return input[offset];
}
});
}
/**
* Like {@link #escapeBytes(ByteString)}, but escapes a text string.
* Non-ASCII characters are first encoded as UTF-8, then each byte is escaped
* individually as a 3-digit octal escape. Yes, it's weird.
*/
static String escapeText(final String input) {
return escapeBytes(ByteString.copyFromUtf8(input));
}
/**
* Escape double quotes and backslashes in a String for unicode output of a message.
*/
static String escapeDoubleQuotesAndBackslashes(final String input) {
return input.replace("\\", "\\\\").replace("\"", "\\\"");
}
}