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Woodstox is a high-performance XML processor that implements Stax (JSR-173),
SAX2 and Stax2 APIs
/* Woodstox XML processor
*
* Copyright (c) 2004 Tatu Saloranta, [email protected]
*
* Licensed under the License specified in file LICENSE, included with
* the source code.
* You may not use this file except in compliance with the License.
*
* 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 com.ctc.wstx.io;
import java.io.*;
import com.ctc.wstx.api.ReaderConfig;
import com.ctc.wstx.cfg.XmlConsts;
/**
* Since JDK does not come with UTF-32/UCS-4, let's implement a simple
* decoder to use.
*/
public final class UTF32Reader
extends BaseReader
{
final boolean mBigEndian;
boolean mXml11;
/**
* Although input is fine with full Unicode set, Java still uses
* 16-bit chars, so we may have to split high-order chars into
* surrogate pairs.
*/
char mSurrogate = NULL_CHAR;
/**
* Total read character count; used for error reporting purposes
*/
int mCharCount = 0;
/**
* Total read byte count; used for error reporting purposes
*/
int mByteCount = 0;
/*
////////////////////////////////////////
// Life-cycle
////////////////////////////////////////
*/
public UTF32Reader(ReaderConfig cfg, InputStream in, byte[] buf, int ptr, int len,
boolean recycleBuffer,
boolean isBigEndian)
{
super(cfg, in, buf, ptr, len, recycleBuffer);
mBigEndian = isBigEndian;
}
@Override
public void setXmlCompliancy(int xmlVersion) {
mXml11 = (xmlVersion == XmlConsts.XML_V_11);
}
/*
////////////////////////////////////////
// Public API
////////////////////////////////////////
*/
@Override
public int read(char[] cbuf, int start, int len) throws IOException
{
// Let's first ensure there's enough room...
if (start < 0 || (start+len) > cbuf.length) {
reportBounds(cbuf, start, len);
}
// Already EOF?
if (mByteBuffer == null) {
return -1;
}
if (len < 1) {
return 0;
}
len += start;
int outPtr = start;
// Ok, first; do we have a surrogate from last round?
if (mSurrogate != NULL_CHAR) {
cbuf[outPtr++] = mSurrogate;
mSurrogate = NULL_CHAR;
// No need to load more, already got one char
} else {
/* Note: we'll try to avoid blocking as much as possible. As a
* result, we only need to get 4 bytes for a full char.
*/
int left = (mByteBufferEnd - mBytePtr);
if (left < 4) {
if (!loadMore(left)) { // (legal) EOF?
return -1;
}
}
}
byte[] buf = mByteBuffer;
main_loop:
while (outPtr < len) {
int ptr = mBytePtr;
int ch;
if (mBigEndian) {
ch = (buf[ptr] << 24) | ((buf[ptr+1] & 0xFF) << 16)
| ((buf[ptr+2] & 0xFF) << 8) | (buf[ptr+3] & 0xFF);
} else {
ch = (buf[ptr] & 0xFF) | ((buf[ptr+1] & 0xFF) << 8)
| ((buf[ptr+2] & 0xFF) << 16) | (buf[ptr+3] << 24);
}
mBytePtr += 4;
// Does it need to be split to surrogates?
// (also, we can and need to verify illegal chars)
if (ch >= 0x7F) {
if (ch <= 0x9F) {
if (mXml11) { // high-order ctrl char detection...
if (ch != 0x85) {
reportInvalid(ch, outPtr-start, "(can only be included via entity in xml 1.1)");
}
ch = CONVERT_NEL_TO;
}
} else if (ch >= 0xD800) {
// Illegal?
if (ch > XmlConsts.MAX_UNICODE_CHAR) {
reportInvalid(ch, outPtr-start,
"(above "+Integer.toHexString(XmlConsts.MAX_UNICODE_CHAR)+") ");
}
if (ch > 0xFFFF) { // need to split into surrogates?
ch -= 0x10000; // to normalize it starting with 0x0
cbuf[outPtr++] = (char) (0xD800 + (ch >> 10));
// hmmh. can this ever be 0? (not legal, at least?)
ch = (0xDC00 | (ch & 0x03FF));
// Room for second part?
if (outPtr >= len) { // nope
mSurrogate = (char) ch;
break main_loop;
}
} else { // in 16-bit range... just need validity checks
if (ch < 0xE000) {
reportInvalid(ch, outPtr-start, "(a surrogate char) ");
} else if (ch >= 0xFFFE) {
reportInvalid(ch, outPtr-start, "");
}
}
} else if (ch == 0x2028 && mXml11) { // LSEP
ch = CONVERT_LSEP_TO;
}
}
cbuf[outPtr++] = (char) ch;
if (mBytePtr >= mByteBufferEnd) {
break main_loop;
}
}
len = outPtr - start;
mCharCount += len;
return len;
}
/*
////////////////////////////////////////
// Internal methods
////////////////////////////////////////
*/
private void reportUnexpectedEOF(int gotBytes, int needed)
throws IOException
{
int bytePos = mByteCount + gotBytes;
int charPos = mCharCount;
throw new CharConversionException("Unexpected EOF in the middle of a 4-byte UTF-32 char: got "
+gotBytes+", needed "+needed
+", at char #"+charPos+", byte #"+bytePos+")");
}
private void reportInvalid(int value, int offset, String msg)
throws IOException
{
int bytePos = mByteCount + mBytePtr - 1;
int charPos = mCharCount + offset;
throw new CharConversionException("Invalid UTF-32 character 0x"
+Integer.toHexString(value)
+msg+" at char #"+charPos+", byte #"+bytePos+")");
}
/**
* @param available Number of "unused" bytes in the input buffer
*
* @return True, if enough bytes were read to allow decoding of at least
* one full character; false if EOF was encountered instead.
*/
private boolean loadMore(int available)
throws IOException
{
mByteCount += (mByteBufferEnd - available);
// Bytes that need to be moved to the beginning of buffer?
if (available > 0) {
/* 11-Nov-2008, TSa: can only move if we own the buffer; otherwise
* we are stuck with the data.
*/
if (mBytePtr > 0 && canModifyBuffer()) {
for (int i = 0; i < available; ++i) {
mByteBuffer[i] = mByteBuffer[mBytePtr+i];
}
mBytePtr = 0;
mByteBufferEnd = available;
}
} else {
/* Ok; here we can actually reasonably expect an EOF,
* so let's do a separate read right away:
*/
int count = readBytes();
if (count < 1) {
if (count < 0) { // -1
freeBuffers(); // to help GC?
return false;
}
// 0 count is no good; let's err out
reportStrangeStream();
}
}
/* Need at least 4 bytes; if we don't get that many, it's an
* error.
*/
while (mByteBufferEnd < 4) {
int count = readBytesAt(mByteBufferEnd);
if (count < 1) {
if (count < 0) { // -1, EOF... no good!
freeBuffers(); // to help GC?
reportUnexpectedEOF(mByteBufferEnd, 4);
}
// 0 count is no good; let's err out
reportStrangeStream();
}
}
return true;
}
}