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/**
* Copyright (c) 2013, impossibl.com
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of impossibl.com nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package com.impossibl.postgres.system.procs;
import com.impossibl.postgres.system.Context;
import com.impossibl.postgres.types.PrimitiveType;
import com.impossibl.postgres.types.Type;
import static com.impossibl.postgres.types.PrimitiveType.Numeric;
import java.io.IOException;
import java.math.BigDecimal;
import org.jboss.netty.buffer.ChannelBuffer;
public class Numerics extends SimpleProcProvider {
private static final short NUMERIC_POS = (short) 0x0000;
private static final short NUMERIC_NEG = (short) 0x4000;
//private static final short NUMERIC_SHORT = (short) 0x8000;
//private static final short NUMERIC_NAN = (short) 0xC000;
private static final short DEC_DIGITS = 4;
public Numerics() {
super(new TxtEncoder(), new TxtDecoder(), new BinEncoder(), new BinDecoder(), "numeric_");
}
static class BinDecoder extends BinaryDecoder {
@Override
public PrimitiveType getInputPrimitiveType() {
return Numeric;
}
@Override
public Class getOutputType() {
return BigDecimal.class;
}
@Override
public BigDecimal decode(Type type, Short typeLength, Integer typeModifier, ChannelBuffer buffer, Context context) throws IOException {
BigDecimal value;
int length = buffer.readInt();
if (length == -1) {
value = null;
}
else if (length < 8) {
throw new IOException("invalid length");
}
else {
int readStart = buffer.readerIndex();
short digitCount = buffer.readShort();
short[] info = new short[3];
info[0] = buffer.readShort(); //weight
info[1] = buffer.readShort(); //sign
info[2] = buffer.readShort(); //displayScale
short[] digits = new short[digitCount];
for (int d = 0; d < digits.length; ++d)
digits[d] = buffer.readShort();
String num = decodeToString(info[0], info[1], info[2], digits);
if (length != buffer.readerIndex() - readStart) {
throw new IOException("invalid length");
}
value = new BigDecimal(num);
}
return value;
}
}
static class BinEncoder extends BinaryEncoder {
@Override
public Class getInputType() {
return BigDecimal.class;
}
@Override
public PrimitiveType getOutputPrimitiveType() {
return Numeric;
}
@Override
public void encode(Type type, ChannelBuffer buffer, Object val, Context context) throws IOException {
buffer.writeInt(-1);
if (val != null) {
int writeStart = buffer.writerIndex();
String num = ((BigDecimal) val).toPlainString();
short[] info = new short[3];
short[] digits = encodeFromString(num, info);
buffer.writeShort(digits.length);
buffer.writeShort(info[0]); //weight
buffer.writeShort(info[1]); //sign
buffer.writeShort(info[2]); //displayScale
for (int d = 0; d < digits.length; ++d)
buffer.writeShort(digits[d]);
//Set length
buffer.setInt(writeStart - 4, buffer.writerIndex() - writeStart);
}
}
}
static class TxtDecoder extends TextDecoder {
@Override
public PrimitiveType getInputPrimitiveType() {
return Numeric;
}
@Override
public Class getOutputType() {
return BigDecimal.class;
}
@Override
public BigDecimal decode(Type type, Short typeLength, Integer typeModifier, CharSequence buffer, Context context) throws IOException {
return new BigDecimal(buffer.toString());
}
}
static class TxtEncoder extends TextEncoder {
@Override
public Class getInputType() {
return BigDecimal.class;
}
@Override
public PrimitiveType getOutputPrimitiveType() {
return Numeric;
}
@Override
public void encode(Type type, StringBuilder buffer, Object val, Context context) throws IOException {
buffer.append(val.toString());
}
}
/**
* Encodes a string of the plain form xxxx.xxx into an NBASE packed sequence
* of shorts.
*
* @param num
* @param info
* @return NBASE encoded version of num
*/
private static short[] encodeFromString(String num, short[] info) {
char[] numChars = num.toCharArray();
byte[] numDigs = new byte[numChars.length - 1 + DEC_DIGITS * 2];
int ch = 0;
int digs = DEC_DIGITS;
boolean haveDP = false;
//Swallow leading zeros
while (numChars[ch] == '0')
ch++;
short sign = NUMERIC_POS;
short displayWeight = -1;
short displayScale = 0;
if (numChars[ch] == '-') {
sign = NUMERIC_NEG;
++ch;
}
/*
* Copy to array of single byte digits
*/
while (ch < numChars.length) {
if (numChars[ch] == '.') {
haveDP = true;
ch++;
}
else {
numDigs[digs++] = (byte) (numChars[ch++] - '0');
if (!haveDP)
displayWeight++;
else
displayScale++;
}
}
digs -= DEC_DIGITS;
/*
* Pack into NBASE format
*/
short weight;
if (displayWeight >= 0)
weight = (short) ((displayWeight + 1 + DEC_DIGITS - 1) / DEC_DIGITS - 1);
else
weight = (short) -((-displayWeight - 1) / DEC_DIGITS + 1);
int offset = (weight + 1) * DEC_DIGITS - (displayWeight + 1);
int digitCount = (digs + offset + DEC_DIGITS - 1) / DEC_DIGITS;
int i = DEC_DIGITS - offset;
short[] digits = new short[digitCount];
int d = 0;
while (digitCount-- > 0) {
digits[d++] = (short) (((numDigs[i] * 10 + numDigs[i + 1]) * 10 + numDigs[i + 2]) * 10 + numDigs[i + 3]);
i += DEC_DIGITS;
}
info[0] = weight;
info[1] = sign;
info[2] = displayScale;
return digits;
}
/**
* Decodes a sequence of digits NBASE packed in shorts into a string of the
* plain form xxxx.xxx
*
* @param weight
* @param sign
* @param displayScale
* @param digits
* @return String representation of the decimal number
*/
private static String decodeToString(short weight, short sign, short displayScale, short[] digits) {
StringBuilder sb = new StringBuilder();
if (sign == NUMERIC_NEG) {
sb.append('-');
}
/*
* Digits before decimal
*/
int d = 0;
if (weight < 0) {
d = weight + 1;
sb.append(0);
}
else {
for (d = 0; d <= weight; d++) {
short dig = d < digits.length ? digits[d] : 0;
boolean putIt = (d > 0);
for (int b = 1000; b > 1; b /= 10) {
short d1 = (short) (dig / b);
dig -= d1 * b;
putIt |= (d1 > 0);
if (putIt)
sb.append((char) (d1 + '0'));
}
sb.append((char) (dig + '0'));
}
}
/*
* Digits after decimal
*/
if (displayScale > 0) {
sb.append('.');
int length = sb.length() + displayScale;
for (int i = 0; i < displayScale; d++, i += DEC_DIGITS) {
short dig = (d >= 0 && d < digits.length) ? digits[d] : 0;
for (int b = 1000; b > 1 && sb.length() < length; b /= 10) {
short d1 = (short) (dig / b);
dig -= d1 * b;
sb.append((char) (d1 + '0'));
}
if (sb.length() < length)
sb.append((char) (dig + '0'));
}
}
return sb.toString();
}
}
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