Files
enjoy/src/main/java/com/jfinal/template/io/LongWriter.java
2017-11-21 22:43:34 +08:00

106 lines
3.1 KiB
Java

/*
* Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*/
package com.jfinal.template.io;
import java.io.IOException;
public class LongWriter {
private static final byte[] minValueBytes = "-9223372036854775808".getBytes();
private static final char[] minValueChars = "-9223372036854775808".toCharArray();
public static void write(ByteWriter byteWriter, long value) throws IOException {
if (value == Long.MIN_VALUE) {
byteWriter.out.write(minValueBytes, 0, minValueBytes.length);
return ;
}
int size = (value < 0) ? stringSize(-value) + 1 : stringSize(value);
char[] chars = byteWriter.chars;
byte[] bytes = byteWriter.bytes;
getChars(value, size, chars);
// int len = Utf8Encoder.me.encode(chars, 0, size, bytes);
// byteWriter.out.write(bytes, 0, len);
for (int j=0; j<size; j++) {
bytes[j] = (byte)chars[j];
}
byteWriter.out.write(bytes, 0, size);
}
public static void write(CharWriter charWriter, long i) throws IOException {
if (i == Long.MIN_VALUE) {
charWriter.out.write(minValueChars, 0, minValueChars.length);
return ;
}
int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
char[] chars = charWriter.chars;
getChars(i, size, chars);
charWriter.out.write(chars, 0, size);
}
static int stringSize(long x) {
long p = 10;
for (int i=1; i<19; i++) {
if (x < p)
return i;
p = 10*p;
}
return 19;
}
static void getChars(long i, int index, char[] buf) {
long q;
int r;
int charPos = index;
char sign = 0;
if (i < 0) {
sign = '-';
i = -i;
}
// Get 2 digits/iteration using longs until quotient fits into an int
while (i > Integer.MAX_VALUE) {
q = i / 100;
// really: r = i - (q * 100);
r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
i = q;
buf[--charPos] = IntegerWriter.DigitOnes[r];
buf[--charPos] = IntegerWriter.DigitTens[r];
}
// Get 2 digits/iteration using ints
int q2;
int i2 = (int)i;
while (i2 >= 65536) {
q2 = i2 / 100;
// really: r = i2 - (q * 100);
r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
i2 = q2;
buf[--charPos] = IntegerWriter.DigitOnes[r];
buf[--charPos] = IntegerWriter.DigitTens[r];
}
// Fall thru to fast mode for smaller numbers
// assert(i2 <= 65536, i2);
for (;;) {
q2 = (i2 * 52429) >>> (16+3);
r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
buf[--charPos] = IntegerWriter.digits[r];
i2 = q2;
if (i2 == 0) break;
}
if (sign != 0) {
buf[--charPos] = sign;
}
}
}