/*
* Copyright (c) 2002, 2003, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package build.tools.generatecharacter;
import java.text.*;
import java.util.*;
public class Utility {
static byte peekByte(String s, int index) {
char c = s.charAt(index/2);
return ((index&1)==0)?(byte)(c>>8):(byte)c;
}
static short peekShort(String s, int index) {
return (short)s.charAt(index);
}
static int peekInt(String s, int index) {
index *= 2;
return (((int)s.charAt(index)) << 16) | s.charAt(index+1);
}
static void poke(String s, int index, byte value) {
int mask = 0xFF00;
int ivalue = value;
if ((index&1)==0) {
ivalue <<= 8;
mask = 0x00FF;
}
index /= 2;
if (index == s.length()) {
s = s + (char)ivalue;
}
else if (index == 0) {
s = (char)(ivalue|(s.charAt(0)&mask)) + s.substring(1);
}
else {
s = s.substring(0, index) + (char)(ivalue|(s.charAt(index)&mask))
+ s.substring(index+1);
}
}
static void poke(String s, int index, short value) {
if (index == s.length()) {
s = s + (char)value;
}
else if (index == 0) {
s = (char)value + s.substring(1);
}
else {
s = s.substring(0, index) + (char)value + s.substring(index+1);
}
}
static void poke(String s, int index, int value) {
index *= 2;
char hi = (char)(value >> 16);
if (index == s.length()) {
s = s + hi + (char)value;
}
else if (index == 0) {
s = hi + (char)value + s.substring(2);
}
else {
s = s.substring(0, index) + hi + (char)value + s.substring(index+2);
}
}
/**
* The ESCAPE character is used during run-length encoding. It signals
* a run of identical chars.
*/
static final char ESCAPE = '\uA5A5';
/**
* The ESCAPE_BYTE character is used during run-length encoding. It signals
* a run of identical bytes.
*/
static final byte ESCAPE_BYTE = (byte)0xA5;
/**
* Construct a string representing a short array. Use run-length encoding.
* A character represents itself, unless it is the ESCAPE character. Then
* the following notations are possible:
* ESCAPE ESCAPE ESCAPE literal
* ESCAPE n c n instances of character c
* Since an encoded run occupies 3 characters, we only encode runs of 4 or
* more characters. Thus we have n > 0 and n != ESCAPE and n <= 0xFFFF.
* If we encounter a run where n == ESCAPE, we represent this as:
* c ESCAPE n-1 c
* The ESCAPE value is chosen so as not to collide with commonly
* seen values.
*/
static final String arrayToRLEString(short[] a) {
StringBuffer buffer = new StringBuffer();
// for (int i=0; i<a.length; ++i) buffer.append((char) a[i]);
buffer.append((char) (a.length >> 16));
buffer.append((char) a.length);
short runValue = a[0];
int runLength = 1;
for (int i=1; i<a.length; ++i) {
short s = a[i];
if (s == runValue && runLength < 0xFFFF) ++runLength;
else {
encodeRun(buffer, runValue, runLength);
runValue = s;
runLength = 1;
}
}
encodeRun(buffer, runValue, runLength);
return buffer.toString();
}
/**
* Construct a string representing a byte array. Use run-length encoding.
* Two bytes are packed into a single char, with a single extra zero byte at
* the end if needed. A byte represents itself, unless it is the
* ESCAPE_BYTE. Then the following notations are possible:
* ESCAPE_BYTE ESCAPE_BYTE ESCAPE_BYTE literal
* ESCAPE_BYTE n b n instances of byte b
* Since an encoded run occupies 3 bytes, we only encode runs of 4 or
* more bytes. Thus we have n > 0 and n != ESCAPE_BYTE and n <= 0xFF.
* If we encounter a run where n == ESCAPE_BYTE, we represent this as:
* b ESCAPE_BYTE n-1 b
* The ESCAPE_BYTE value is chosen so as not to collide with commonly
* seen values.
*/
static final String arrayToRLEString(byte[] a) {
StringBuffer buffer = new StringBuffer();
buffer.append((char) (a.length >> 16));
buffer.append((char) a.length);
byte runValue = a[0];
int runLength = 1;
byte[] state = new byte[2];
for (int i=1; i<a.length; ++i) {
byte b = a[i];
if (b == runValue && runLength < 0xFF) ++runLength;
else {
encodeRun(buffer, runValue, runLength, state);
runValue = b;
runLength = 1;
}
}
encodeRun(buffer, runValue, runLength, state);
// We must save the final byte, if there is one, by padding
// an extra zero.
if (state[0] != 0) appendEncodedByte(buffer, (byte)0, state);
return buffer.toString();
}
/**
* Encode a run, possibly a degenerate run (of < 4 values).
* @param length The length of the run; must be > 0 && <= 0xFFFF.
*/
private static final void encodeRun(StringBuffer buffer, short value, int length) {
if (length < 4) {
for (int j=0; j<length; ++j) {
if (value == (int) ESCAPE) buffer.append(ESCAPE);
buffer.append((char) value);
}
}
else {
if (length == (int) ESCAPE) {
if (value == (int) ESCAPE) buffer.append(ESCAPE);
buffer.append((char) value);
--length;
}
buffer.append(ESCAPE);
buffer.append((char) length);
buffer.append((char) value); // Don't need to escape this value
}
}
/**
* Encode a run, possibly a degenerate run (of < 4 values).
* @param length The length of the run; must be > 0 && <= 0xFF.
*/
private static final void encodeRun(StringBuffer buffer, byte value, int length,
byte[] state) {
if (length < 4) {
for (int j=0; j<length; ++j) {
if (value == ESCAPE_BYTE) appendEncodedByte(buffer, ESCAPE_BYTE, state);
appendEncodedByte(buffer, value, state);
}
}
else {
if (length == ESCAPE_BYTE) {
if (value == ESCAPE_BYTE) appendEncodedByte(buffer, ESCAPE_BYTE, state);
appendEncodedByte(buffer, value, state);
--length;
}
appendEncodedByte(buffer, ESCAPE_BYTE, state);
appendEncodedByte(buffer, (byte)length, state);
appendEncodedByte(buffer, value, state); // Don't need to escape this value
}
}
/**
* Append a byte to the given StringBuffer, packing two bytes into each
* character. The state parameter maintains intermediary data between
* calls.
* @param state A two-element array, with state[0] == 0 if this is the
* first byte of a pair, or state[0] != 0 if this is the second byte
* of a pair, in which case state[1] is the first byte.
*/
private static final void appendEncodedByte(StringBuffer buffer, byte value,
byte[] state) {
if (state[0] != 0) {
char c = (char) ((state[1] << 8) | (((int) value) & 0xFF));
buffer.append(c);
state[0] = 0;
}
else {
state[0] = 1;
state[1] = value;
}
}
/**
* Construct an array of shorts from a run-length encoded string.
*/
static final short[] RLEStringToShortArray(String s) {
int length = (((int) s.charAt(0)) << 16) | ((int) s.charAt(1));
short[] array = new short[length];
int ai = 0;
for (int i=2; i<s.length(); ++i) {
char c = s.charAt(i);
if (c == ESCAPE) {
c = s.charAt(++i);
if (c == ESCAPE) array[ai++] = (short) c;
else {
int runLength = (int) c;
short runValue = (short) s.charAt(++i);
for (int j=0; j<runLength; ++j) array[ai++] = runValue;
}
}
else {
array[ai++] = (short) c;
}
}
if (ai != length)
throw new InternalError("Bad run-length encoded short array");
return array;
}
/**
* Construct an array of bytes from a run-length encoded string.
*/
static final byte[] RLEStringToByteArray(String s) {
int length = (((int) s.charAt(0)) << 16) | ((int) s.charAt(1));
byte[] array = new byte[length];
boolean nextChar = true;
char c = 0;
int node = 0;
int runLength = 0;
int i = 2;
for (int ai=0; ai<length; ) {
// This part of the loop places the next byte into the local
// variable 'b' each time through the loop. It keeps the
// current character in 'c' and uses the boolean 'nextChar'
// to see if we've taken both bytes out of 'c' yet.
byte b;
if (nextChar) {
c = s.charAt(i++);
b = (byte) (c >> 8);
nextChar = false;
}
else {
b = (byte) (c & 0xFF);
nextChar = true;
}
// This part of the loop is a tiny state machine which handles
// the parsing of the run-length encoding. This would be simpler
// if we could look ahead, but we can't, so we use 'node' to
// move between three nodes in the state machine.
switch (node) {
case 0:
// Normal idle node
if (b == ESCAPE_BYTE) {
node = 1;
}
else {
array[ai++] = b;
}
break;
case 1:
// We have seen one ESCAPE_BYTE; we expect either a second
// one, or a run length and value.
if (b == ESCAPE_BYTE) {
array[ai++] = ESCAPE_BYTE;
node = 0;
}
else {
runLength = b;
// Interpret signed byte as unsigned
if (runLength < 0) runLength += 0x100;
node = 2;
}
break;
case 2:
// We have seen an ESCAPE_BYTE and length byte. We interpret
// the next byte as the value to be repeated.
for (int j=0; j<runLength; ++j) array[ai++] = b;
node = 0;
break;
}
}
if (node != 0)
throw new InternalError("Bad run-length encoded byte array");
if (i != s.length())
throw new InternalError("Excess data in RLE byte array string");
return array;
}
/**
* Format a String for representation in a source file. This includes
* breaking it into lines escaping characters using octal notation
* when necessary (control characters and double quotes).
*/
static final String formatForSource(String s) {
return formatForSource(s, " ");
}
/**
* Format a String for representation in a source file. This includes
* breaking it into lines escaping characters using octal notation
* when necessary (control characters and double quotes).
*/
static final String formatForSource(String s, String indent) {
StringBuffer buffer = new StringBuffer();
for (int i=0; i<s.length();) {
if (i > 0) buffer.append("+\n");
int limit = buffer.length() + 78; // Leave 2 for trailing <"+>
buffer.append(indent + '"');
while (i<s.length() && buffer.length()<limit) {
char c = s.charAt(i++);
/* This works too but it's kind of unnecessary; might as
well keep things simple.
if (c == '\\' || c == '"') {
// Escape backslash and double-quote. Don't need to
// escape single-quote.
buffer.append("\\" + c);
}
else if (c >= '\u0020' && c <= '\u007E') {
// Printable ASCII ranges from ' ' to '~'
buffer.append(c);
}
else
*/
if (c <= '\377') {
// Represent control characters
// using octal notation; otherwise the string we form
// won't compile, since Unicode escape sequences are
// processed before tokenization.
buffer.append('\\');
buffer.append(HEX_DIGIT[(c & 0700) >> 6]); // HEX_DIGIT works for octal
buffer.append(HEX_DIGIT[(c & 0070) >> 3]);
buffer.append(HEX_DIGIT[(c & 0007)]);
}
else {
// Handle the rest with Unicode
buffer.append("\\u");
buffer.append(HEX_DIGIT[(c & 0xF000) >> 12]);
buffer.append(HEX_DIGIT[(c & 0x0F00) >> 8]);
buffer.append(HEX_DIGIT[(c & 0x00F0) >> 4]);
buffer.append(HEX_DIGIT[(c & 0x000F)]);
}
}
buffer.append('"');
}
return buffer.toString();
}
static final char[] HEX_DIGIT = {'0','1','2','3','4','5','6','7',
'8','9','A','B','C','D','E','F'};
}