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/*******************************************************************************
* Copyright (c) 2009-2011 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
******************************************************************************/
package org.luaj.vm2;
import java.io.ByteArrayInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import org.luaj.vm2.lib.MathLib;
import org.luaj.vm2.lib.StringLib;
/**
* Subclass of {@link LuaValue} for representing lua strings.
*
* Because lua string values are more nearly sequences of bytes than
* sequences of characters or unicode code points, the {@link LuaString}
* implementation holds the string value in an internal byte array.
*
* {@link LuaString} values are generally not mutable once constructed,
* so multiple {@link LuaString} values can chare a single byte array.
*
* Currently {@link LuaString}s are pooled via a centrally managed weak table.
* To ensure that as many string values as possible take advantage of this,
* Constructors are not exposed directly. As with number, booleans, and nil,
* instance construction should be via {@link LuaValue#valueOf(byte[])} or similar API.
*
* When Java Strings are used to initialize {@link LuaString} data, the UTF8 encoding is assumed.
* The functions
* {@link LuaString#lengthAsUtf8(char[]),
* {@link LuaString#encodeToUtf8(char[], int, byte[], int)}, and
* {@link LuaString#decodeAsUtf8(byte[], int, int)
* are used to convert back and forth between UTF8 byte arrays and character arrays.
*
* @see LuaValue
* @see LuaValue#valueOf(String)
* @see LuaValue#valueOf(byte[])
*/
public class LuaString extends LuaValue {
/** Size of cache of recent short strings. This is the maximum number of LuaStrings that
* will be retained in the cache of recent short strings. */
public static final int RECENT_STRINGS_CACHE_SIZE = 128;
/** Maximum length of a string to be considered for recent short strings caching.
* This effectively limits the total memory that can be spent on the recent strings cache,
* ecause no LuaString whose backing exceeds this length will be put into the cache. */
public static final int RECENT_STRINGS_MAX_LENGTH = 32;
/** The singleton instance representing lua {@code true} */
public static LuaValue s_metatable;
/** The bytes for the string */
public final byte[] m_bytes;
/** The offset into the byte array, 0 means start at the first byte */
public final int m_offset;
/** The number of bytes that comprise this string */
public final int m_length;
private static class Cache {
/** Simple cache of recently created strings that are short.
* This is simply a list of strings, indexed by their hash codes modulo the cache size
* that have been recently constructed. If a string is being constructed frequently
* from different contexts, it will generally may show up as a cache hit and resolve
* to the same value. */
public final LuaString recent_short_strings[] = new LuaString[RECENT_STRINGS_CACHE_SIZE];
public LuaString get(LuaString s) {
final int index = s.hashCode() & (RECENT_STRINGS_CACHE_SIZE - 1);
final LuaString cached = (LuaString) recent_short_strings[index];
if (cached != null && s.raweq(cached))
return cached;
recent_short_strings[index] = s;
return s;
}
static final Cache instance = new Cache();
}
/**
* Get a {@link LuaString} instance whose bytes match
* the supplied Java String using the UTF8 encoding.
* @param string Java String containing characters to encode as UTF8
* @return {@link LuaString} with UTF8 bytes corresponding to the supplied String
*/
public static LuaString valueOf(String string) {
char[] c = string.toCharArray();
byte[] b = new byte[lengthAsUtf8(c)];
encodeToUtf8(c, c.length, b, 0);
return valueOf(b, 0, b.length);
}
// TODO: should this be deprecated or made private?
/** Construct a {@link LuaString} around a byte array that may be used directly as the backing.
*
* The array may be used as the backing for this object, so clients must not change contents.
* If the supplied value for 'len' is more than half the length of the container, the
* supplied byte array will be used as the backing, otherwise the bytes will be copied to a
* new byte array, and cache lookup may be performed.
*
* @param bytes byte buffer
* @param off offset into the byte buffer
* @param len length of the byte buffer
* @return {@link LuaString} wrapping the byte buffer
*/
public static LuaString valueOf(byte[] bytes, int off, int len) {
if (bytes.length < RECENT_STRINGS_MAX_LENGTH) {
// Short string. Reuse the backing and check the cache of recent strings before returning.
final LuaString s = new LuaString(bytes, off, len);
return Cache.instance.get( s );
} else if (len >= bytes.length / 2) {
// Reuse backing only when more than half the bytes are part of the result.
return new LuaString(bytes, off, len);
} else {
// Short result relative to the source. Copy only the bytes that are actually to be used.
final byte[] b = new byte[len];
System.arraycopy(bytes, off, b, 0, len);
return valueOf(b, 0, len); // To possibly use cached version.
}
}
/** Construct a {@link LuaString} using the supplied characters as byte values.
*
* Only the low-order 8-bits of each character are used, the remainder is ignored.
*
* This is most useful for constructing byte sequences that do not conform to UTF8.
* @param bytes array of char, whose values are truncated at 8-bits each and put into a byte array.
* @return {@link LuaString} wrapping a copy of the byte buffer
*/
public static LuaString valueOf(char[] bytes) {
return valueOf(bytes, 0, bytes.length);
}
/** Construct a {@link LuaString} using the supplied characters as byte values.
*
* Only the low-order 8-bits of each character are used, the remainder is ignored.
*
* This is most useful for constructing byte sequences that do not conform to UTF8.
* @param bytes array of char, whose values are truncated at 8-bits each and put into a byte array.
* @return {@link LuaString} wrapping a copy of the byte buffer
*/
public static LuaString valueOf(char[] bytes, int off, int len) {
byte[] b = new byte[len];
for ( int i=0; i
* The array may be used directly as the backing, so clients must not change contents.
*
* @param bytes byte buffer
* @return {@link LuaString} wrapping the byte buffer
*/
public static LuaString valueOf(byte[] bytes) {
return valueOf(bytes, 0, bytes.length);
}
/** Construct a {@link LuaString} around a byte array without copying the contents.
*
* The array is used directly after this is called, so clients must not change contents.
*
* @param bytes byte buffer
* @param offset offset into the byte buffer
* @param length length of the byte buffer
* @return {@link LuaString} wrapping the byte buffer
*/
private LuaString(byte[] bytes, int offset, int length) {
this.m_bytes = bytes;
this.m_offset = offset;
this.m_length = length;
}
public boolean isstring() {
return true;
}
public LuaValue getmetatable() {
return s_metatable;
}
public int type() {
return LuaValue.TSTRING;
}
public String typename() {
return "string";
}
public String tojstring() {
return decodeAsUtf8(m_bytes, m_offset, m_length);
}
// get is delegated to the string library
public LuaValue get(LuaValue key) {
return s_metatable!=null? gettable(this,key): StringLib.instance.get(key);
}
// unary operators
public LuaValue neg() { double d = scannumber(); return Double.isNaN(d)? super.neg(): valueOf(-d); }
// basic binary arithmetic
public LuaValue add( LuaValue rhs ) { double d = scannumber(); return Double.isNaN(d)? arithmt(ADD,rhs): rhs.add(d); }
public LuaValue add( double rhs ) { return valueOf( checkarith() + rhs ); }
public LuaValue add( int rhs ) { return valueOf( checkarith() + rhs ); }
public LuaValue sub( LuaValue rhs ) { double d = scannumber(); return Double.isNaN(d)? arithmt(SUB,rhs): rhs.subFrom(d); }
public LuaValue sub( double rhs ) { return valueOf( checkarith() - rhs ); }
public LuaValue sub( int rhs ) { return valueOf( checkarith() - rhs ); }
public LuaValue subFrom( double lhs ) { return valueOf( lhs - checkarith() ); }
public LuaValue mul( LuaValue rhs ) { double d = scannumber(); return Double.isNaN(d)? arithmt(MUL,rhs): rhs.mul(d); }
public LuaValue mul( double rhs ) { return valueOf( checkarith() * rhs ); }
public LuaValue mul( int rhs ) { return valueOf( checkarith() * rhs ); }
public LuaValue pow( LuaValue rhs ) { double d = scannumber(); return Double.isNaN(d)? arithmt(POW,rhs): rhs.powWith(d); }
public LuaValue pow( double rhs ) { return MathLib.dpow(checkarith(),rhs); }
public LuaValue pow( int rhs ) { return MathLib.dpow(checkarith(),rhs); }
public LuaValue powWith( double lhs ) { return MathLib.dpow(lhs, checkarith()); }
public LuaValue powWith( int lhs ) { return MathLib.dpow(lhs, checkarith()); }
public LuaValue div( LuaValue rhs ) { double d = scannumber(); return Double.isNaN(d)? arithmt(DIV,rhs): rhs.divInto(d); }
public LuaValue div( double rhs ) { return LuaDouble.ddiv(checkarith(),rhs); }
public LuaValue div( int rhs ) { return LuaDouble.ddiv(checkarith(),rhs); }
public LuaValue divInto( double lhs ) { return LuaDouble.ddiv(lhs, checkarith()); }
public LuaValue mod( LuaValue rhs ) { double d = scannumber(); return Double.isNaN(d)? arithmt(MOD,rhs): rhs.modFrom(d); }
public LuaValue mod( double rhs ) { return LuaDouble.dmod(checkarith(), rhs); }
public LuaValue mod( int rhs ) { return LuaDouble.dmod(checkarith(), rhs); }
public LuaValue modFrom( double lhs ) { return LuaDouble.dmod(lhs, checkarith()); }
// relational operators, these only work with other strings
public LuaValue lt( LuaValue rhs ) { return rhs.strcmp(this)>0? LuaValue.TRUE: FALSE; }
public boolean lt_b( LuaValue rhs ) { return rhs.strcmp(this)>0; }
public boolean lt_b( int rhs ) { typerror("attempt to compare string with number"); return false; }
public boolean lt_b( double rhs ) { typerror("attempt to compare string with number"); return false; }
public LuaValue lteq( LuaValue rhs ) { return rhs.strcmp(this)>=0? LuaValue.TRUE: FALSE; }
public boolean lteq_b( LuaValue rhs ) { return rhs.strcmp(this)>=0; }
public boolean lteq_b( int rhs ) { typerror("attempt to compare string with number"); return false; }
public boolean lteq_b( double rhs ) { typerror("attempt to compare string with number"); return false; }
public LuaValue gt( LuaValue rhs ) { return rhs.strcmp(this)<0? LuaValue.TRUE: FALSE; }
public boolean gt_b( LuaValue rhs ) { return rhs.strcmp(this)<0; }
public boolean gt_b( int rhs ) { typerror("attempt to compare string with number"); return false; }
public boolean gt_b( double rhs ) { typerror("attempt to compare string with number"); return false; }
public LuaValue gteq( LuaValue rhs ) { return rhs.strcmp(this)<=0? LuaValue.TRUE: FALSE; }
public boolean gteq_b( LuaValue rhs ) { return rhs.strcmp(this)<=0; }
public boolean gteq_b( int rhs ) { typerror("attempt to compare string with number"); return false; }
public boolean gteq_b( double rhs ) { typerror("attempt to compare string with number"); return false; }
// concatenation
public LuaValue concat(LuaValue rhs) { return rhs.concatTo(this); }
public Buffer concat(Buffer rhs) { return rhs.concatTo(this); }
public LuaValue concatTo(LuaNumber lhs) { return concatTo(lhs.strvalue()); }
public LuaValue concatTo(LuaString lhs) {
byte[] b = new byte[lhs.m_length+this.m_length];
System.arraycopy(lhs.m_bytes, lhs.m_offset, b, 0, lhs.m_length);
System.arraycopy(this.m_bytes, this.m_offset, b, lhs.m_length, this.m_length);
return valueOf(b, 0, b.length);
}
// string comparison
public int strcmp(LuaValue lhs) { return -lhs.strcmp(this); }
public int strcmp(LuaString rhs) {
for ( int i=0, j=0; i>5)+1; /* if string is too long, don't hash all its chars */
for (int l1=m_length; l1>=step; l1-=step) /* compute hash */
h = h ^ ((h<<5)+(h>>2)+(((int) m_bytes[m_offset+l1-1] ) & 0x0FF ));
return h;
}
// object comparison, used in key comparison
public boolean equals( Object o ) {
if ( o instanceof LuaString ) {
return raweq( (LuaString) o );
}
return false;
}
// equality w/ metatable processing
public LuaValue eq( LuaValue val ) { return val.raweq(this)? TRUE: FALSE; }
public boolean eq_b( LuaValue val ) { return val.raweq(this); }
// equality w/o metatable processing
public boolean raweq( LuaValue val ) {
return val.raweq(this);
}
public boolean raweq( LuaString s ) {
if ( this == s )
return true;
if ( s.m_length != m_length )
return false;
if ( s.m_bytes == m_bytes && s.m_offset == m_offset )
return true;
if ( s.hashCode() != hashCode() )
return false;
for ( int i=0; i=0 )
if ( a[i++]!=b[j++] )
return false;
return true;
}
public void write(DataOutputStream writer, int i, int len) throws IOException {
writer.write(m_bytes,m_offset+i,len);
}
public LuaValue len() {
return LuaInteger.valueOf(m_length);
}
public int length() {
return m_length;
}
public int rawlen() {
return m_length;
}
public int luaByte(int index) {
return m_bytes[m_offset + index] & 0x0FF;
}
public int charAt( int index ) {
if ( index < 0 || index >= m_length )
throw new IndexOutOfBoundsException();
return luaByte( index );
}
public String checkjstring() {
return tojstring();
}
public LuaString checkstring() {
return this;
}
/** Convert value to an input stream.
*
* @return {@link InputStream} whose data matches the bytes in this {@link LuaString}
*/
public InputStream toInputStream() {
return new ByteArrayInputStream(m_bytes, m_offset, m_length);
}
/**
* Copy the bytes of the string into the given byte array.
* @param strOffset offset from which to copy
* @param bytes destination byte array
* @param arrayOffset offset in destination
* @param len number of bytes to copy
*/
public void copyInto( int strOffset, byte[] bytes, int arrayOffset, int len ) {
System.arraycopy( m_bytes, m_offset+strOffset, bytes, arrayOffset, len );
}
/** Java version of strpbrk - find index of any byte that in an accept string.
* @param accept {@link LuaString} containing characters to look for.
* @return index of first match in the {@code accept} string, or -1 if not found.
*/
public int indexOfAny( LuaString accept ) {
final int ilimit = m_offset + m_length;
final int jlimit = accept.m_offset + accept.m_length;
for ( int i = m_offset; i < ilimit; ++i ) {
for ( int j = accept.m_offset; j < jlimit; ++j ) {
if ( m_bytes[i] == accept.m_bytes[j] ) {
return i - m_offset;
}
}
}
return -1;
}
/**
* Find the index of a byte starting at a point in this string
* @param b the byte to look for
* @param start the first index in the string
* @return index of first match found, or -1 if not found.
*/
public int indexOf( byte b, int start ) {
for ( int i=start; i < m_length; ++i ) {
if ( m_bytes[m_offset+i] == b )
return i;
}
return -1;
}
/**
* Find the index of a string starting at a point in this string
* @param s the string to search for
* @param start the first index in the string
* @return index of first match found, or -1 if not found.
*/
public int indexOf( LuaString s, int start ) {
final int slen = s.length();
final int limit = m_length - slen;
for ( int i=start; i <= limit; ++i ) {
if ( equals( m_bytes, m_offset+i, s.m_bytes, s.m_offset, slen ) )
return i;
}
return -1;
}
/**
* Find the last index of a string in this string
* @param s the string to search for
* @return index of last match found, or -1 if not found.
*/
public int lastIndexOf( LuaString s ) {
final int slen = s.length();
final int limit = m_length - slen;
for ( int i=limit; i >= 0; --i ) {
if ( equals( m_bytes, m_offset+i, s.m_bytes, s.m_offset, slen ) )
return i;
}
return -1;
}
/**
* Convert to Java String interpreting as utf8 characters.
*
* @param bytes byte array in UTF8 encoding to convert
* @param offset starting index in byte array
* @param length number of bytes to convert
* @return Java String corresponding to the value of bytes interpreted using UTF8
* @see #lengthAsUtf8(char[])
* @see #encodeToUtf8(char[], int, byte[], int)
* @see #isValidUtf8()
*/
public static String decodeAsUtf8(byte[] bytes, int offset, int length) {
int i,j,n,b;
for ( i=offset,j=offset+length,n=0; i=0||i>=j)? b:
(b<-32||i+1>=j)? (((b&0x3f) << 6) | (bytes[i++]&0x3f)):
(((b&0xf) << 12) | ((bytes[i++]&0x3f)<<6) | (bytes[i++]&0x3f)));
}
return new String(chars);
}
/**
* Count the number of bytes required to encode the string as UTF-8.
* @param chars Array of unicode characters to be encoded as UTF-8
* @return count of bytes needed to encode using UTF-8
* @see #encodeToUtf8(char[], int, byte[], int)
* @see #decodeAsUtf8(byte[], int, int)
* @see #isValidUtf8()
*/
public static int lengthAsUtf8(char[] chars) {
int i,b;
char c;
for ( i=b=chars.length; --i>=0; )
if ( (c=chars[i]) >=0x80 )
b += (c>=0x800)? 2: 1;
return b;
}
/**
* Encode the given Java string as UTF-8 bytes, writing the result to bytes
* starting at offset.
*
* The string should be measured first with lengthAsUtf8
* to make sure the given byte array is large enough.
* @param chars Array of unicode characters to be encoded as UTF-8
* @param nchars Number of characters in the array to convert.
* @param bytes byte array to hold the result
* @param off offset into the byte array to start writing
* @return number of bytes converted.
* @see #lengthAsUtf8(char[])
* @see #decodeAsUtf8(byte[], int, int)
* @see #isValidUtf8()
*/
public static int encodeToUtf8(char[] chars, int nchars, byte[] bytes, int off) {
char c;
int j = off;
for ( int i=0; i>6) & 0x1f));
bytes[j++] = (byte) (0x80 | ( c & 0x3f));
} else {
bytes[j++] = (byte) (0xE0 | ((c>>12) & 0x0f));
bytes[j++] = (byte) (0x80 | ((c>>6) & 0x3f));
bytes[j++] = (byte) (0x80 | ( c & 0x3f));
}
}
return j - off;
}
/** Check that a byte sequence is valid UTF-8
* @return true if it is valid UTF-8, otherwise false
* @see #lengthAsUtf8(char[])
* @see #encodeToUtf8(char[], int, byte[], int)
* @see #decodeAsUtf8(byte[], int, int)
*/
public boolean isValidUtf8() {
int i,j,n,b,e=0;
for ( i=m_offset,j=m_offset+m_length,n=0; i= 0 ) continue;
if ( ((c & 0xE0) == 0xC0)
&& i=j )
return Double.NaN;
if ( m_bytes[i]=='0' && i+1 36 )
return Double.NaN;
int i=m_offset,j=m_offset+m_length;
while ( i=j )
return Double.NaN;
return scanlong( base, i, j );
}
/**
* Scan and convert a long value, or return Double.NaN if not found.
* @param base the base to use, such as 10
* @param start the index to start searching from
* @param end the first index beyond the search range
* @return double value if conversion is valid,
* or Double.NaN if not
*/
private double scanlong( int base, int start, int end ) {
long x = 0;
boolean neg = (m_bytes[start] == '-');
for ( int i=(neg?start+1:start); i='0'&&m_bytes[i]<='9')? '0':
m_bytes[i]>='A'&&m_bytes[i]<='Z'? ('A'-10): ('a'-10));
if ( digit < 0 || digit >= base )
return Double.NaN;
x = x * base + digit;
if ( x < 0 )
return Double.NaN; // overflow
}
return neg? -x: x;
}
/**
* Scan and convert a double value, or return Double.NaN if not a double.
* @param start the index to start searching from
* @param end the first index beyond the search range
* @return double value if conversion is valid,
* or Double.NaN if not
*/
private double scandouble(int start, int end) {
if ( end>start+64 ) end=start+64;
for ( int i=start; i