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*
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* published by the Free Software Foundation. Oracle designates this
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package com.oracle.objectfile.io;
import java.io.CharConversionException;
import java.nio.ByteBuffer;
Implements UTF-8 encoding and decoding of strings with support for zero-bytes as string
terminators.
/**
* Implements UTF-8 encoding and decoding of strings with support for zero-bytes as string
* terminators.
*/
public final class Utf8 {
private Utf8() {
}
Returns: the length in bytes of the UTF8 representation of the string
/**
* @return the length in bytes of the UTF8 representation of the string
*/
public static int utf8Length(String string) {
return utf8Length(string, 0, string.length());
}
Params: - beginIndex – first index that is part of the region, inclusive
- endIndex – index at the end of the region, exclusive
Returns: the length in bytes of the UTF8 representation of the string region
/**
* @param beginIndex first index that is part of the region, inclusive
* @param endIndex index at the end of the region, exclusive
* @return the length in bytes of the UTF8 representation of the string region
*/
public static int utf8Length(String s, int beginIndex, int endIndex) {
if (beginIndex < 0 || endIndex > s.length() || beginIndex > endIndex) {
throw new StringIndexOutOfBoundsException();
}
int length = 0;
for (int i = beginIndex; i < endIndex; i++) {
final int c = s.charAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
length++;
} else if (c > 0x07FF) {
length += 3;
} else {
length += 2;
}
}
return length;
}
Writes an UTF8-encoded string region to a given byte buffer.
Params: - dest – the byte buffer to write to
- source – the String to be written
- beginIndex – first index in
source that is part of the region, inclusive - endIndex – index in
source at the end of the region, exclusive - zeroTerminate – whether to write a final zero byte
/**
* Writes an UTF8-encoded string region to a given byte buffer.
*
* @param dest the byte buffer to write to
* @param source the String to be written
* @param beginIndex first index in {@code source} that is part of the region, inclusive
* @param endIndex index in {@code source} at the end of the region, exclusive
* @param zeroTerminate whether to write a final zero byte
*/
public static void substringToUtf8(ByteBuffer dest, String source, int beginIndex, int endIndex, boolean zeroTerminate) {
if (beginIndex < 0 || endIndex > source.length() || beginIndex > endIndex) {
throw new StringIndexOutOfBoundsException();
}
for (int i = beginIndex; i < endIndex; i++) {
final char c = source.charAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
dest.put((byte) c);
} else if (c > 0x07FF) {
dest.put((byte) (0xe0 | (byte) (c >> 12)));
dest.put((byte) (0x80 | ((c & 0xfc0) >> 6)));
dest.put((byte) (0x80 | (c & 0x3f)));
} else {
dest.put((byte) (0xc0 | (byte) (c >> 6)));
dest.put((byte) (0x80 | (c & 0x3f)));
}
}
if (zeroTerminate) {
dest.put((byte) 0);
}
}
Converts a byte buffer of UTF-8 data to a String. The entire buffer until the buffer's limit is converted unless zeroTerminated is true, in which case conversion stops at the first zero byte. Params: - zeroTerminated – if true, then a 0 byte marks the end of the string, and character '\0'
in the input must be encoded as two bytes as opposed to one
- source – the byte buffer to read from
Returns: the decoded string
/**
* Converts a byte buffer of UTF-8 data to a String. The entire buffer until the
* {@link ByteBuffer#limit() buffer's limit} is converted unless {@code zeroTerminated} is
* {@code true}, in which case conversion stops at the first zero byte.
*
* @param zeroTerminated if true, then a 0 byte marks the end of the string, and character '\0'
* in the input must be encoded as two bytes as opposed to one
* @param source the byte buffer to read from
* @return the decoded string
*/
public static String utf8ToString(boolean zeroTerminated, ByteBuffer source) throws CharConversionException {
final StringBuilder sb = new StringBuilder();
while (source.hasRemaining()) {
final int c0 = source.get() & 0xff;
if (zeroTerminated && c0 == 0) {
break;
}
switch (c0 >> 4) {
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7: {
/* 0xxxxxxx */
sb.append((char) c0);
break;
}
case 12:
case 13: {
/* 110x xxxx 10xx xxxx */
final int c1 = source.get();
if ((c1 & 0xC0) != 0x80) {
throw new CharConversionException();
}
sb.append((char) (((c0 & 0x1F) << 6) | (c1 & 0x3F)));
break;
}
case 14: {
/* 1110 xxxx 10xx xxxx 10xx xxxx */
final int c1 = source.get();
final int c2 = source.get();
if (((c1 & 0xC0) != 0x80) || ((c2 & 0xC0) != 0x80)) {
throw new CharConversionException();
}
sb.append((char) (((c0 & 0x0F) << 12) | ((c1 & 0x3F) << 6) | (c2 & 0x3F)));
break;
}
default: {
/* 10xx xxxx, 1111 xxxx */
throw new CharConversionException();
}
}
}
return sb.toString();
}
}