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  /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.
  */
 
 package org.apache.jasper.xmlparser;
 
 import static org.jboss.web.JasperMessages.MESSAGES;
 
 import java.io.Reader;

Author(s):
Andy Clark, IBM
Version:
$Id: UTF8Reader.java 515 2008-03-17 21:02:23Z jfrederic.clere@jboss.com $
 
 public class UTF8Reader
     extends Reader {
 
     //
     // Constants
     //
 
    
Default byte buffer size (2048).
 
     public static final int DEFAULT_BUFFER_SIZE = 2048;
 
     //
     // Data
     //
 
    
Input stream.
 
     protected InputStream fInputStream;

    
Byte buffer.
 
     protected byte[] fBuffer;

    
Offset into buffer.
 
     protected int fOffset;

    
Surrogate character.
 
     private int fSurrogate = -1;
 
     //
     // Constructors
     //
 
    
Constructs a UTF-8 reader from the specified input stream, buffer size and MessageFormatter.

Parameters:
inputStream The input stream.
size The initial buffer size.
 
     public UTF8Reader(InputStream inputStreamint size) {
          = inputStream;
          = new byte[size];
     }
 
     //
     // Reader methods
     //
 
    
Read a single character. This method will block until a character is available, an I/O error occurs, or the end of the stream is reached.

Subclasses that intend to support efficient single-character input should override this method.

Returns:
The character read, as an integer in the range 0 to 16383 (0x00-0xffff), or -1 if the end of the stream has been reached
Throws:
java.io.IOException If an I/O error occurs
 
     public int read() throws IOException {
 
         // decode character
         int c = ;
         if ( == -1) {
             // NOTE: We use the index into the buffer if there are remaining
             //       bytes from the last block read. -Ac
             int index = 0;
 
            // get first byte
            int b0 = index ==  
                   ? .read() : [index++] & 0x00FF;
            if (b0 == -1) {
                return -1;
            }
            // UTF-8:   [0xxx xxxx]
            // Unicode: [0000 0000] [0xxx xxxx]
            if (b0 < 0x80) {
                c = (char)b0;
            }
            // UTF-8:   [110y yyyy] [10xx xxxx]
            // Unicode: [0000 0yyy] [yyxx xxxx]
            else if ((b0 & 0xE0) == 0xC0) {
                int b1 = index ==  
                       ? .read() : [index++] & 0x00FF;
                if (b1 == -1) {
                    expectedByte(2, 2);
                }
                if ((b1 & 0xC0) != 0x80) {
                    invalidByte(2, 2, b1);
                }
                c = ((b0 << 6) & 0x07C0) | (b1 & 0x003F);
            }
            // UTF-8:   [1110 zzzz] [10yy yyyy] [10xx xxxx]
            // Unicode: [zzzz yyyy] [yyxx xxxx]
            else if ((b0 & 0xF0) == 0xE0) {
                int b1 = index == 
                       ? .read() : [index++] & 0x00FF;
                if (b1 == -1) {
                    expectedByte(2, 3);
                }
                if ((b1 & 0xC0) != 0x80) {
                    invalidByte(2, 3, b1);
                }
                int b2 = index ==  
                       ? .read() : [index++] & 0x00FF;
                if (b2 == -1) {
                    expectedByte(3, 3);
                }
                if ((b2 & 0xC0) != 0x80) {
                    invalidByte(3, 3, b2);
                }
                c = ((b0 << 12) & 0xF000) | ((b1 << 6) & 0x0FC0) |
                    (b2 & 0x003F);
            }
            // UTF-8:   [1111 0uuu] [10uu zzzz] [10yy yyyy] [10xx xxxx]*
            // Unicode: [1101 10ww] [wwzz zzyy] (high surrogate)
            //          [1101 11yy] [yyxx xxxx] (low surrogate)
            //          * uuuuu = wwww + 1
            else if ((b0 & 0xF8) == 0xF0) {
                int b1 = index ==  
                       ? .read() : [index++] & 0x00FF;
                if (b1 == -1) {
                    expectedByte(2, 4);
                }
                if ((b1 & 0xC0) != 0x80) {
                    invalidByte(2, 3, b1);
                }
                int b2 = index ==  
                       ? .read() : [index++] & 0x00FF;
                if (b2 == -1) {
                    expectedByte(3, 4);
                }
                if ((b2 & 0xC0) != 0x80) {
                    invalidByte(3, 3, b2);
                }
                int b3 = index ==  
                       ? .read() : [index++] & 0x00FF;
                if (b3 == -1) {
                    expectedByte(4, 4);
                }
                if ((b3 & 0xC0) != 0x80) {
                    invalidByte(4, 4, b3);
                }
                int uuuuu = ((b0 << 2) & 0x001C) | ((b1 >> 4) & 0x0003);
                if (uuuuu > 0x10) {
                    invalidSurrogate(uuuuu);
                }
                int wwww = uuuuu - 1;
                int hs = 0xD800 | 
                         ((wwww << 6) & 0x03C0) | ((b1 << 2) & 0x003C) | 
                         ((b2 >> 4) & 0x0003);
                int ls = 0xDC00 | ((b2 << 6) & 0x03C0) | (b3 & 0x003F);
                c = hs;
                 = ls;
            }
            // error
            else {
                invalidByte(1, 1, b0);
            }
        }
        // use surrogate
        else {
             = -1;
        }
        return c;
    } // read():int

    
Read characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Parameters:
ch Destination buffer
offset Offset at which to start storing characters
length Maximum number of characters to read
Returns:
The number of characters read, or -1 if the end of the stream has been reached
Throws:
java.io.IOException If an I/O error occurs
    public int read(char ch[], int offsetint lengththrows IOException {
        // handle surrogate
        int out = offset;
        if ( != -1) {
            ch[offset + 1] = (char);
             = -1;
            length--;
            out++;
        }
        // read bytes
        int count = 0;
        if ( == 0) {
            // adjust length to read
            if (length > .) {
                length = .;
            }
            // perform read operation
            count = .read(, 0, length);
            if (count == -1) {
                return -1;
            }
            count += out - offset;
        }
        // skip read; last character was in error
        // NOTE: Having an offset value other than zero means that there was
        //       an error in the last character read. In this case, we have
        //       skipped the read so we don't consume any bytes past the 
        //       error. By signalling the error on the next block read we
        //       allow the method to return the most valid characters that
        //       it can on the previous block read. -Ac
        else {
            count = ;
             = 0;
        }
        // convert bytes to characters
        final int total = count;
        for (int in = 0; in < totalin++) {
            int b0 = [in] & 0x00FF;
            // UTF-8:   [0xxx xxxx]
            // Unicode: [0000 0000] [0xxx xxxx]
            if (b0 < 0x80) {
                ch[out++] = (char)b0;
                continue;
            }
            // UTF-8:   [110y yyyy] [10xx xxxx]
            // Unicode: [0000 0yyy] [yyxx xxxx]
            if ((b0 & 0xE0) == 0xC0) {
                int b1 = -1;
                if (++in < total) { 
                    b1 = [in] & 0x00FF; 
                }
                else {
                    b1 = .read();
                    if (b1 == -1) {
                        if (out > offset) {
                            [0] = (byte)b0;
                             = 1;
                            return out - offset;
                        }
                        expectedByte(2, 2);
                    }
                    count++;
                }
                if ((b1 & 0xC0) != 0x80) {
                    if (out > offset) {
                        [0] = (byte)b0;
                        [1] = (byte)b1;
                         = 2;
                        return out - offset;
                    }
                    invalidByte(2, 2, b1);
                }
                int c = ((b0 << 6) & 0x07C0) | (b1 & 0x003F);
                ch[out++] = (char)c;
                count -= 1;
                continue;
            }
            // UTF-8:   [1110 zzzz] [10yy yyyy] [10xx xxxx]
            // Unicode: [zzzz yyyy] [yyxx xxxx]
            if ((b0 & 0xF0) == 0xE0) {
                int b1 = -1;
                if (++in < total) { 
                    b1 = [in] & 0x00FF; 
                }
                else {
                    b1 = .read();
                    if (b1 == -1) {
                        if (out > offset) {
                            [0] = (byte)b0;
                             = 1;
                            return out - offset;
                        }
                        expectedByte(2, 3);
                    }
                    count++;
                }
                if ((b1 & 0xC0) != 0x80) {
                    if (out > offset) {
                        [0] = (byte)b0;
                        [1] = (byte)b1;
                         = 2;
                        return out - offset;
                    }
                    invalidByte(2, 3, b1);
                }
                int b2 = -1;
                if (++in < total) { 
                    b2 = [in] & 0x00FF; 
                }
                else {
                    b2 = .read();
                    if (b2 == -1) {
                        if (out > offset) {
                            [0] = (byte)b0;
                            [1] = (byte)b1;
                             = 2;
                            return out - offset;
                        }
                        expectedByte(3, 3);
                    }
                    count++;
                }
                if ((b2 & 0xC0) != 0x80) {
                    if (out > offset) {
                        [0] = (byte)b0;
                        [1] = (byte)b1;
                        [2] = (byte)b2;
                         = 3;
                        return out - offset;
                    }
                    invalidByte(3, 3, b2);
                }
                int c = ((b0 << 12) & 0xF000) | ((b1 << 6) & 0x0FC0) |
                        (b2 & 0x003F);
                ch[out++] = (char)c;
                count -= 2;
                continue;
            }
            // UTF-8:   [1111 0uuu] [10uu zzzz] [10yy yyyy] [10xx xxxx]*
            // Unicode: [1101 10ww] [wwzz zzyy] (high surrogate)
            //          [1101 11yy] [yyxx xxxx] (low surrogate)
            //          * uuuuu = wwww + 1
            if ((b0 & 0xF8) == 0xF0) {
                int b1 = -1;
                if (++in < total) { 
                    b1 = [in] & 0x00FF; 
                }
                else {
                    b1 = .read();
                    if (b1 == -1) {
                        if (out > offset) {
                            [0] = (byte)b0;
                             = 1;
                            return out - offset;
                        }
                        expectedByte(2, 4);
                    }
                    count++;
                }
                if ((b1 & 0xC0) != 0x80) {
                    if (out > offset) {
                        [0] = (byte)b0;
                        [1] = (byte)b1;
                         = 2;
                        return out - offset;
                    }
                    invalidByte(2, 4, b1);
                }
                int b2 = -1;
                if (++in < total) { 
                    b2 = [in] & 0x00FF; 
                }
                else {
                    b2 = .read();
                    if (b2 == -1) {
                        if (out > offset) {
                            [0] = (byte)b0;
                            [1] = (byte)b1;
                             = 2;
                            return out - offset;
                        }
                        expectedByte(3, 4);
                    }
                    count++;
                }
                if ((b2 & 0xC0) != 0x80) {
                    if (out > offset) {
                        [0] = (byte)b0;
                        [1] = (byte)b1;
                        [2] = (byte)b2;
                         = 3;
                        return out - offset;
                    }
                    invalidByte(3, 4, b2);
                }
                int b3 = -1;
                if (++in < total) { 
                    b3 = [in] & 0x00FF; 
                }
                else {
                    b3 = .read();
                    if (b3 == -1) {
                        if (out > offset) {
                            [0] = (byte)b0;
                            [1] = (byte)b1;
                            [2] = (byte)b2;
                             = 3;
                            return out - offset;
                        }
                        expectedByte(4, 4);
                    }
                    count++;
                }
                if ((b3 & 0xC0) != 0x80) {
                    if (out > offset) {
                        [0] = (byte)b0;
                        [1] = (byte)b1;
                        [2] = (byte)b2;
                        [3] = (byte)b3;
                         = 4;
                        return out - offset;
                    }
                    invalidByte(4, 4, b2);
                }
                // decode bytes into surrogate characters
                int uuuuu = ((b0 << 2) & 0x001C) | ((b1 >> 4) & 0x0003);
                if (uuuuu > 0x10) {
                    invalidSurrogate(uuuuu);
                }
                int wwww = uuuuu - 1;
                int zzzz = b1 & 0x000F;
                int yyyyyy = b2 & 0x003F;
                int xxxxxx = b3 & 0x003F;
                int hs = 0xD800 | ((wwww << 6) & 0x03C0) | (zzzz << 2) | (yyyyyy >> 4);
                int ls = 0xDC00 | ((yyyyyy << 6) & 0x03C0) | xxxxxx;
                // set characters
                ch[out++] = (char)hs;
                ch[out++] = (char)ls;
                count -= 2;
                continue;
            }
            // error
            if (out > offset) {
                [0] = (byte)b0;
                 = 1;
                return out - offset;
            }
            invalidByte(1, 1, b0);
        }
        return count;
    } // read(char[],int,int)

    
Skip characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

Parameters:
n The number of characters to skip
Returns:
The number of characters actually skipped
Throws:
java.io.IOException If an I/O error occurs
    public long skip(long nthrows IOException {
        long remaining = n;
        final char[] ch = new char[.];
        do {
            int length = ch.length < remaining ? ch.length : (int)remaining;
            int count = read(ch, 0, length);
            if (count > 0) {
                remaining -= count;
            }
            else {
                break;
            }
        } while (remaining > 0);
        long skipped = n - remaining;
        return skipped;
    } // skip(long):long

    
Tell whether this stream is ready to be read.

Returns:
True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
Throws:
java.io.IOException If an I/O error occurs
    public boolean ready() throws IOException {
	    return false;
    } // ready()

    
Tell whether this stream supports the mark() operation.
    public boolean markSupported() {
	    return false;
    } // markSupported()

    
Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point. Not all character-input streams support the mark() operation.

Parameters:
readAheadLimit Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.
Throws:
java.io.IOException If the stream does not support mark(), or if some other I/O error occurs
    public void mark(int readAheadLimitthrows IOException {
    }

    
Reset the stream. If the stream has been marked, then attempt to reposition it at the mark. If the stream has not been marked, then attempt to reset it in some way appropriate to the particular stream, for example by repositioning it to its starting point. Not all character-input streams support the reset() operation, and some support reset() without supporting mark().

Throws:
java.io.IOException If the stream has not been marked, or if the mark has been invalidated, or if the stream does not support reset(), or if some other I/O error occurs
    public void reset() throws IOException {
         = 0;
         = -1;
    } // reset()

    
Close the stream. Once a stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously-closed stream, however, has no effect.

Throws:
java.io.IOException If an I/O error occurs
    public void close() throws IOException {
        .close();
    } // close()
    //
    // Private methods
    //

    
Throws an exception for expected byte.
    private void expectedByte(int positionint count)
        throws UTFDataFormatException {
        throw new UTFDataFormatException(.errorUtf8ExpectedByte(positioncount));
    } // expectedByte(int,int,int)

    
Throws an exception for invalid byte.
    private void invalidByte(int positionint countint c
        throws UTFDataFormatException {
        throw new UTFDataFormatException(.errorUtf8InvalidByte(positioncount));
    } // invalidByte(int,int,int,int)

    
Throws an exception for invalid surrogate bits.
    private void invalidSurrogate(int uuuuuthrows UTFDataFormatException {
        throw new UTFDataFormatException(.errorUtf8InvalidHighSurrogate(Integer.toHexString(uuuuu)));
    } // invalidSurrogate(int)
// class UTF8Reader
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