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/*
*******************************************************************************
* (C) Copyright IBM Corp. 1996-2005 - All Rights Reserved *
* *
* The original version of this source code and documentation is copyrighted *
* and owned by IBM, These materials are provided under terms of a License *
* Agreement between IBM and Sun. This technology is protected by multiple *
* US and International patents. This notice and attribution to IBM may not *
* to removed. *
*******************************************************************************
*/
package sun.text.normalizer;
import java.io.InputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Arrays;
/**
* <p>A trie is a kind of compressed, serializable table of values
* associated with Unicode code points (0..0x10ffff).</p>
* <p>This class defines the basic structure of a trie and provides methods
* to <b>retrieve the offsets to the actual data</b>.</p>
* <p>Data will be the form of an array of basic types, char or int.</p>
* <p>The actual data format will have to be specified by the user in the
* inner static interface com.ibm.icu.impl.Trie.DataManipulate.</p>
* <p>This trie implementation is optimized for getting offset while walking
* forward through a UTF-16 string.
* Therefore, the simplest and fastest access macros are the
* fromLead() and fromOffsetTrail() methods.
* The fromBMP() method are a little more complicated; they get offsets even
* for lead surrogate codepoints, while the fromLead() method get special
* "folded" offsets for lead surrogate code units if there is relevant data
* associated with them.
* From such a folded offsets, an offset needs to be extracted to supply
* to the fromOffsetTrail() methods.
* To handle such supplementary codepoints, some offset information are kept
* in the data.</p>
* <p>Methods in com.ibm.icu.impl.Trie.DataManipulate are called to retrieve
* that offset from the folded value for the lead surrogate unit.</p>
* <p>For examples of use, see com.ibm.icu.impl.CharTrie or
* com.ibm.icu.impl.IntTrie.</p>
* @author synwee
* @see com.ibm.icu.impl.CharTrie
* @see com.ibm.icu.impl.IntTrie
* @since release 2.1, Jan 01 2002
*/
public abstract class Trie
{
// public class declaration ----------------------------------------
/**
* Character data in com.ibm.impl.Trie have different user-specified format
* for different purposes.
* This interface specifies methods to be implemented in order for
* com.ibm.impl.Trie, to surrogate offset information encapsulated within
* the data.
* @draft 2.1
*/
public static interface DataManipulate
{
/**
* Called by com.ibm.icu.impl.Trie to extract from a lead surrogate's
* data
* the index array offset of the indexes for that lead surrogate.
* @param value data value for a surrogate from the trie, including the
* folding offset
* @return data offset or 0 if there is no data for the lead surrogate
* @draft 2.1
*/
public int getFoldingOffset(int value);
}
// protected constructor -------------------------------------------
/**
* Trie constructor for CharTrie use.
* @param inputStream ICU data file input stream which contains the
* trie
* @param dataManipulate object containing the information to parse the
* trie data
* @throws IOException thrown when input stream does not have the
* right header.
* @draft 2.1
*/
protected Trie(InputStream inputStream,
DataManipulate dataManipulate) throws IOException
{
DataInputStream input = new DataInputStream(inputStream);
// Magic number to authenticate the data.
int signature = input.readInt();
m_options_ = input.readInt();
if (!checkHeader(signature)) {
throw new IllegalArgumentException("ICU data file error: Trie header authentication failed, please check if you have the most updated ICU data file");
}
m_dataManipulate_ = dataManipulate;
m_isLatin1Linear_ = (m_options_ &
HEADER_OPTIONS_LATIN1_IS_LINEAR_MASK_) != 0;
m_dataOffset_ = input.readInt();
m_dataLength_ = input.readInt();
unserialize(inputStream);
}
/**
* Trie constructor
* @param index array to be used for index
* @param options used by the trie
* @param dataManipulate object containing the information to parse the
* trie data
* @draft 2.2
*/
protected Trie(char index[], int options, DataManipulate dataManipulate)
{
m_options_ = options;
m_dataManipulate_ = dataManipulate;
m_isLatin1Linear_ = (m_options_ &
HEADER_OPTIONS_LATIN1_IS_LINEAR_MASK_) != 0;
m_index_ = index;
m_dataOffset_ = m_index_.length;
}
// protected data members ------------------------------------------
/**
* Lead surrogate code points' index displacement in the index array.
* 0x10000-0xd800=0x2800
* 0x2800 >> INDEX_STAGE_1_SHIFT_
*/
protected static final int LEAD_INDEX_OFFSET_ = 0x2800 >> 5;
/**
* Shift size for shifting right the input index. 1..9
* @draft 2.1
*/
protected static final int INDEX_STAGE_1_SHIFT_ = 5;
/**
* Shift size for shifting left the index array values.
* Increases possible data size with 16-bit index values at the cost
* of compactability.
* This requires blocks of stage 2 data to be aligned by
* DATA_GRANULARITY.
* 0..INDEX_STAGE_1_SHIFT
* @draft 2.1
*/
protected static final int INDEX_STAGE_2_SHIFT_ = 2;
/**
* Mask for getting the lower bits from the input index.
* DATA_BLOCK_LENGTH_ - 1.
* @draft 2.1
*/
protected static final int INDEX_STAGE_3_MASK_ =
(1 << INDEX_STAGE_1_SHIFT_) - 1;
/**
* Surrogate mask to use when shifting offset to retrieve supplementary
* values
* @draft 2.1
*/
protected static final int SURROGATE_MASK_ = 0x3FF;
/**
* Index or UTF16 characters
* @draft 2.1
*/
protected char m_index_[];
/**
* Internal TrieValue which handles the parsing of the data value.
* This class is to be implemented by the user
* @draft 2.1
*/
protected DataManipulate m_dataManipulate_;
/**
* Start index of the data portion of the trie. CharTrie combines
* index and data into a char array, so this is used to indicate the
* initial offset to the data portion.
* Note this index always points to the initial value.
* @draft 2.1
*/
protected int m_dataOffset_;
/**
* Length of the data array
*/
protected int m_dataLength_;
// protected methods -----------------------------------------------
/**
* Gets the offset to the data which the surrogate pair points to.
* @param lead lead surrogate
* @param trail trailing surrogate
* @return offset to data
* @draft 2.1
*/
protected abstract int getSurrogateOffset(char lead, char trail);
/**
* Gets the value at the argument index
* @param index value at index will be retrieved
* @return 32 bit value
* @draft 2.1
*/
protected abstract int getValue(int index);
/**
* Gets the default initial value
* @return 32 bit value
* @draft 2.1
*/
protected abstract int getInitialValue();
/**
* Gets the offset to the data which the index ch after variable offset
* points to.
* Note for locating a non-supplementary character data offset, calling
* <p>
* getRawOffset(0, ch);
* </p>
* will do. Otherwise if it is a supplementary character formed by
* surrogates lead and trail. Then we would have to call getRawOffset()
* with getFoldingIndexOffset(). See getSurrogateOffset().
* @param offset index offset which ch is to start from
* @param ch index to be used after offset
* @return offset to the data
* @draft 2.1
*/
protected final int getRawOffset(int offset, char ch)
{
return (m_index_[offset + (ch >> INDEX_STAGE_1_SHIFT_)]
<< INDEX_STAGE_2_SHIFT_)
+ (ch & INDEX_STAGE_3_MASK_);
}
/**
* Gets the offset to data which the BMP character points to
* Treats a lead surrogate as a normal code point.
* @param ch BMP character
* @return offset to data
* @draft 2.1
*/
protected final int getBMPOffset(char ch)
{
return (ch >= UTF16.LEAD_SURROGATE_MIN_VALUE
&& ch <= UTF16.LEAD_SURROGATE_MAX_VALUE)
? getRawOffset(LEAD_INDEX_OFFSET_, ch)
: getRawOffset(0, ch);
// using a getRawOffset(ch) makes no diff
}
/**
* Gets the offset to the data which this lead surrogate character points
* to.
* Data at the returned offset may contain folding offset information for
* the next trailing surrogate character.
* @param ch lead surrogate character
* @return offset to data
* @draft 2.1
*/
protected final int getLeadOffset(char ch)
{
return getRawOffset(0, ch);
}
/**
* Internal trie getter from a code point.
* Could be faster(?) but longer with
* if((c32)<=0xd7ff) { (result)=_TRIE_GET_RAW(trie, data, 0, c32); }
* Gets the offset to data which the codepoint points to
* @param ch codepoint
* @return offset to data
* @draft 2.1
*/
protected final int getCodePointOffset(int ch)
{
// if ((ch >> 16) == 0) slower
if (ch >= UTF16.CODEPOINT_MIN_VALUE
&& ch < UTF16.SUPPLEMENTARY_MIN_VALUE) {
// BMP codepoint
return getBMPOffset((char)ch);
}
// for optimization
if (ch >= UTF16.CODEPOINT_MIN_VALUE
&& ch <= UCharacter.MAX_VALUE) {
// look at the construction of supplementary characters
// trail forms the ends of it.
return getSurrogateOffset(UTF16.getLeadSurrogate(ch),
(char)(ch & SURROGATE_MASK_));
}
// return -1 if there is an error, in this case we return
return -1;
}
/**
* <p>Parses the inputstream and creates the trie index with it.</p>
* <p>This is overwritten by the child classes.
* @param inputStream input stream containing the trie information
* @exception IOException thrown when data reading fails.
* @draft 2.1
*/
protected void unserialize(InputStream inputStream) throws IOException
{
//indexLength is a multiple of 1024 >> INDEX_STAGE_2_SHIFT_
m_index_ = new char[m_dataOffset_];
DataInputStream input = new DataInputStream(inputStream);
for (int i = 0; i < m_dataOffset_; i ++) {
m_index_[i] = input.readChar();
}
}
/**
* Determines if this is a 32 bit trie
* @return true if options specifies this is a 32 bit trie
* @draft 2.1
*/
protected final boolean isIntTrie()
{
return (m_options_ & HEADER_OPTIONS_DATA_IS_32_BIT_) != 0;
}
/**
* Determines if this is a 16 bit trie
* @return true if this is a 16 bit trie
* @draft 2.1
*/
protected final boolean isCharTrie()
{
return (m_options_ & HEADER_OPTIONS_DATA_IS_32_BIT_) == 0;
}
// private data members --------------------------------------------
/**
* Signature index
*/
private static final int HEADER_SIGNATURE_INDEX_ = 0;
/**
* Options index
*/
private static final int HEADER_OPTIONS_INDEX_ = 1 << 1;
/**
* Index length index
*/
private static final int HEADER_INDEX_LENGTH_INDEX_ = 2 << 1;
/**
* Data length index
*/
private static final int HEADER_DATA_LENGTH_INDEX_ = 3 << 1;
/**
* Size of header
*/
private static final int HEADER_LENGTH_ = 4 << 1;
/**
* Latin 1 option mask
*/
private static final int HEADER_OPTIONS_LATIN1_IS_LINEAR_MASK_ = 0x200;
/**
* Constant number to authenticate the byte block
*/
private static final int HEADER_SIGNATURE_ = 0x54726965;
/**
* Header option formatting
*/
private static final int HEADER_OPTIONS_SHIFT_MASK_ = 0xF;
private static final int HEADER_OPTIONS_INDEX_SHIFT_ = 4;
private static final int HEADER_OPTIONS_DATA_IS_32_BIT_ = 0x100;
/**
* Flag indicator for Latin quick access data block
*/
private boolean m_isLatin1Linear_;
/**
* <p>Trie options field.</p>
* <p>options bit field:<br>
* 9 1 = Latin-1 data is stored linearly at data + DATA_BLOCK_LENGTH<br>
* 8 0 = 16-bit data, 1=32-bit data<br>
* 7..4 INDEX_STAGE_1_SHIFT // 0..INDEX_STAGE_2_SHIFT<br>
* 3..0 INDEX_STAGE_2_SHIFT // 1..9<br>
*/
private int m_options_;
// private methods ---------------------------------------------------
/**
* Authenticates raw data header.
* Checking the header information, signature and options.
* @param rawdata array of char data to be checked
* @return true if the header is authenticated valid
* @draft 2.1
*/
private final boolean checkHeader(int signature)
{
// check the signature
// Trie in big-endian US-ASCII (0x54726965).
// Magic number to authenticate the data.
if (signature != HEADER_SIGNATURE_) {
return false;
}
if ((m_options_ & HEADER_OPTIONS_SHIFT_MASK_) !=
INDEX_STAGE_1_SHIFT_ ||
((m_options_ >> HEADER_OPTIONS_INDEX_SHIFT_) &
HEADER_OPTIONS_SHIFT_MASK_)
!= INDEX_STAGE_2_SHIFT_) {
return false;
}
return true;
}
}