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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2000-2012. All Rights Reserved.
*
* 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.
*
* %CopyrightEnd%
*/
package com.ericsson.otp.erlang;
import java.io.UnsupportedEncodingException;
/**
* Provides a Java representation of Erlang strings.
*/
public class OtpErlangString extends OtpErlangObject {
// don't change this!
private static final long serialVersionUID = -7053595217604929233L;
private final String str;
/**
* Create an Erlang string from the given string.
*/
public OtpErlangString(final String str) {
this.str = str;
}
/**
* Create an Erlang string from a list of integers.
*
* @throws OtpErlangException
* for non-proper and non-integer lists.
* @throws OtpErlangRangeException
* if an integer in the list is not a valid Unicode code point
* according to Erlang.
*/
public OtpErlangString(final OtpErlangList list) throws OtpErlangException {
final String s = list.stringValue();
final int n = s.length();
for (int i = 0; i < n; i = s.offsetByCodePoints(i, 1)) {
final int cp = s.codePointAt(i);
if (!isValidCodePoint(cp)) {
throw new OtpErlangRangeException("Invalid CodePoint: " + cp);
}
}
str = s;
}
/**
* Create an Erlang string from a stream containing a string encoded in
* Erlang external format.
*
* @param buf
* the stream containing the encoded string.
*
* @exception OtpErlangDecodeException
* if the buffer does not contain a valid external
* representation of an Erlang string.
*/
public OtpErlangString(final OtpInputStream buf)
throws OtpErlangDecodeException {
str = buf.read_string();
}
/**
* Get the actual string contained in this object.
*
* @return the raw string contained in this object, without regard to Erlang
* quoting rules.
*
* @see #toString
*/
public String stringValue() {
return str;
}
/**
* Get the printable version of the string contained in this object.
*
* @return the string contained in this object, quoted.
*
* @see #stringValue
*/
@Override
public String toString() {
return "\"" + str + "\"";
}
/**
* Convert this string to the equivalent Erlang external representation.
*
* @param buf
* an output stream to which the encoded string should be
* written.
*/
@Override
public void encode(final OtpOutputStream buf) {
buf.write_string(str);
}
/**
* Determine if two strings are equal. They are equal if they represent the
* same sequence of characters. This method can be used to compare
* OtpErlangStrings with each other and with Strings.
*
* @param o
* the OtpErlangString or String to compare to.
*
* @return true if the strings consist of the same sequence of characters,
* false otherwise.
*/
@Override
public boolean equals(final Object o) {
if (o instanceof String) {
return str.compareTo((String) o) == 0;
} else if (o instanceof OtpErlangString) {
return str.compareTo(((OtpErlangString) o).str) == 0;
}
return false;
}
@Override
protected int doHashCode() {
return str.hashCode();
}
/**
* Create Unicode code points from a String.
*
* @param s
* a String to convert to an Unicode code point array
*
* @return the corresponding array of integers representing Unicode code
* points
*/
public static int[] stringToCodePoints(final String s) {
final int m = s.codePointCount(0, s.length());
final int[] codePoints = new int[m];
int j = 0;
for (int offset = 0; offset < s.length();) {
final int codepoint = s.codePointAt(offset);
codePoints[j++] = codepoint;
offset += Character.charCount(codepoint);
}
return codePoints;
}
/**
* Validate a code point according to Erlang definition; Unicode 3.0. That
* is; valid in the range U+0..U+10FFFF, but not in the range U+D800..U+DFFF
* (surrogat pairs).
*
* @param cp
* the code point value to validate
*
* @return true if the code point is valid, false otherwise.
*/
public static boolean isValidCodePoint(final int cp) {
// Erlang definition of valid Unicode code points;
// Unicode 3.0, XML, et.al.
return cp >>> 16 <= 0x10 // in 0..10FFFF; Unicode range
&& (cp & ~0x7FF) != 0xD800; // not in D800..DFFF; surrogate
// range
}
/**
* Construct a String from a Latin-1 (ISO-8859-1) encoded byte array, if
* Latin-1 is available, otherwise use the default encoding.
*
*/
public static String newString(final byte[] bytes) {
try {
return new String(bytes, "ISO-8859-1");
} catch (final UnsupportedEncodingException e) {
}
return new String(bytes);
}
}
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