slowr | 60d4d10 | 2017-08-16 18:33:58 -0700 | [diff] [blame^] | 1 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| 4 | package org.onosproject.xran.codecs.ber.types; |
| 5 | |
| 6 | import com.fasterxml.jackson.annotation.JsonIgnore; |
| 7 | import com.fasterxml.jackson.annotation.JsonValue; |
| 8 | import org.onosproject.xran.codecs.ber.BerByteArrayOutputStream; |
| 9 | import org.onosproject.xran.codecs.ber.BerLength; |
| 10 | import org.onosproject.xran.codecs.ber.BerTag; |
| 11 | import org.onosproject.xran.codecs.ber.internal.Util; |
| 12 | |
| 13 | import java.io.EOFException; |
| 14 | import java.io.IOException; |
| 15 | import java.io.InputStream; |
| 16 | import java.io.Serializable; |
| 17 | import java.math.BigInteger; |
| 18 | |
| 19 | public class BerReal implements Serializable { |
| 20 | |
| 21 | public final static BerTag tag = new BerTag(BerTag.UNIVERSAL_CLASS, BerTag.PRIMITIVE, BerTag.REAL_TAG); |
| 22 | private static final long serialVersionUID = 1L; |
| 23 | @JsonIgnore |
| 24 | public byte[] code = null; |
| 25 | |
| 26 | public double value; |
| 27 | |
| 28 | public BerReal() { |
| 29 | } |
| 30 | |
| 31 | public BerReal(byte[] code) { |
| 32 | this.code = code; |
| 33 | } |
| 34 | |
| 35 | public BerReal(double value) { |
| 36 | this.value = value; |
| 37 | } |
| 38 | |
| 39 | public int encode(BerByteArrayOutputStream os) throws IOException { |
| 40 | return encode(os, true); |
| 41 | } |
| 42 | |
| 43 | public int encode(BerByteArrayOutputStream os, boolean withTag) throws IOException { |
| 44 | |
| 45 | if (code != null) { |
| 46 | for (int i = code.length - 1; i >= 0; i--) { |
| 47 | os.write(code[i]); |
| 48 | } |
| 49 | if (withTag) { |
| 50 | return tag.encode(os) + code.length; |
| 51 | } |
| 52 | return code.length; |
| 53 | } |
| 54 | |
| 55 | int codeLength = encodeValue(os); |
| 56 | |
| 57 | codeLength += BerLength.encodeLength(os, codeLength); |
| 58 | |
| 59 | if (withTag) { |
| 60 | codeLength += tag.encode(os); |
| 61 | } |
| 62 | |
| 63 | return codeLength; |
| 64 | } |
| 65 | |
| 66 | private int encodeValue(BerByteArrayOutputStream os) throws IOException { |
| 67 | |
| 68 | // explained in Annex C and Ch. 8.5 of X.690 |
| 69 | |
| 70 | // we use binary encoding, with base 2 and F==0 |
| 71 | // F is only needed when encoding with base 8 or 16 |
| 72 | |
| 73 | long longBits = Double.doubleToLongBits(value); |
| 74 | |
| 75 | boolean isNegative = (longBits & 0x8000000000000000L) == 0x8000000000000000L; |
| 76 | |
| 77 | int exponent = ((int) (longBits >> 52)) & 0x7ff; |
| 78 | |
| 79 | long mantissa = (longBits & 0x000fffffffffffffL) | 0x0010000000000000L; |
| 80 | |
| 81 | if (exponent == 0x7ff) { |
| 82 | if (mantissa == 0x0010000000000000L) { |
| 83 | if (isNegative) { |
| 84 | // - infinity |
| 85 | os.write(0x41); |
| 86 | } else { |
| 87 | // + infinity |
| 88 | os.write(0x40); |
| 89 | } |
| 90 | return 1; |
| 91 | } else { |
| 92 | throw new IOException("NAN not supported"); |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | if ((exponent == 0 && mantissa == 0x0010000000000000L)) { |
| 97 | // zero |
| 98 | return 0; |
| 99 | } |
| 100 | |
| 101 | // because IEEE double-precision format is (-1)^sign * 1.b51b50..b0 * 2^(e-1023) we need to subtract 1023 and 52 |
| 102 | // from the exponent to get an exponent corresponding to an integer matissa as need here. |
| 103 | exponent -= 1075; // 1023 + 52 = 1075 |
| 104 | |
| 105 | // trailing zeros of the mantissa should be removed. Therefor find out how much the mantissa can be shifted and |
| 106 | // the exponent can be increased |
| 107 | int exponentIncr = 0; |
| 108 | while (((mantissa >> exponentIncr) & 0xff) == 0x00) { |
| 109 | exponentIncr += 8; |
| 110 | } |
| 111 | while (((mantissa >> exponentIncr) & 0x01) == 0x00) { |
| 112 | exponentIncr++; |
| 113 | } |
| 114 | |
| 115 | exponent += exponentIncr; |
| 116 | mantissa >>= exponentIncr; |
| 117 | |
| 118 | int mantissaLength = (Long.SIZE - Long.numberOfLeadingZeros(mantissa) + 7) / 8; |
| 119 | |
| 120 | for (int i = 0; i < mantissaLength; i++) { |
| 121 | os.write((int) (mantissa >> (8 * i))); |
| 122 | } |
| 123 | int codeLength = mantissaLength; |
| 124 | |
| 125 | byte[] exponentBytes = BigInteger.valueOf(exponent).toByteArray(); |
| 126 | os.write(exponentBytes); |
| 127 | codeLength += exponentBytes.length; |
| 128 | |
| 129 | byte exponentFormat = 0; |
| 130 | if (exponentBytes.length < 4) { |
| 131 | exponentFormat = (byte) (exponentBytes.length - 1); |
| 132 | } else { |
| 133 | os.write(exponentBytes.length); |
| 134 | codeLength++; |
| 135 | exponentFormat = 0x03; |
| 136 | } |
| 137 | |
| 138 | if (isNegative) { |
| 139 | os.write(0x80 | 0x40 | exponentFormat); |
| 140 | } else { |
| 141 | os.write(0x80 | exponentFormat); |
| 142 | } |
| 143 | |
| 144 | codeLength++; |
| 145 | |
| 146 | return codeLength; |
| 147 | } |
| 148 | |
| 149 | public int decode(InputStream is) throws IOException { |
| 150 | return decode(is, true); |
| 151 | } |
| 152 | |
| 153 | public int decode(InputStream is, boolean withTag) throws IOException { |
| 154 | |
| 155 | int codeLength = 0; |
| 156 | |
| 157 | if (withTag) { |
| 158 | codeLength += tag.decodeAndCheck(is); |
| 159 | } |
| 160 | |
| 161 | BerLength length = new BerLength(); |
| 162 | codeLength += length.decode(is); |
| 163 | |
| 164 | if (length.val == 0) { |
| 165 | value = 0; |
| 166 | return codeLength; |
| 167 | } |
| 168 | |
| 169 | if (length.val == 1) { |
| 170 | int nextByte = is.read(); |
| 171 | if (nextByte == -1) { |
| 172 | throw new EOFException("Unexpected end of input stream."); |
| 173 | } |
| 174 | if (nextByte == 0x40) { |
| 175 | value = Double.POSITIVE_INFINITY; |
| 176 | } else if (nextByte == 0x41) { |
| 177 | value = Double.NEGATIVE_INFINITY; |
| 178 | } else { |
| 179 | throw new IOException("invalid real encoding"); |
| 180 | } |
| 181 | return codeLength + 1; |
| 182 | } |
| 183 | |
| 184 | byte[] byteCode = new byte[length.val]; |
| 185 | Util.readFully(is, byteCode); |
| 186 | |
| 187 | if ((byteCode[0] & 0x80) != 0x80) { |
| 188 | throw new IOException("Only binary REAL encoding is supported"); |
| 189 | } |
| 190 | |
| 191 | codeLength += length.val; |
| 192 | int tempLength = 1; |
| 193 | |
| 194 | int sign = 1; |
| 195 | if ((byteCode[0] & 0x40) == 0x40) { |
| 196 | sign = -1; |
| 197 | } |
| 198 | |
| 199 | int exponentLength = (byteCode[0] & 0x03) + 1; |
| 200 | if (exponentLength == 4) { |
| 201 | exponentLength = byteCode[1]; |
| 202 | tempLength++; |
| 203 | } |
| 204 | |
| 205 | tempLength += exponentLength; |
| 206 | |
| 207 | int exponent = 0; |
| 208 | for (int i = 0; i < exponentLength; i++) { |
| 209 | exponent |= byteCode[1 + i] << (8 * (exponentLength - i - 1)); |
| 210 | } |
| 211 | |
| 212 | long mantissa = 0; |
| 213 | for (int i = 0; i < length.val - tempLength; i++) { |
| 214 | mantissa |= (byteCode[i + tempLength] & 0xffL) << (8 * (length.val - tempLength - i - 1)); |
| 215 | } |
| 216 | |
| 217 | value = sign * mantissa * Math.pow(2, exponent); |
| 218 | |
| 219 | return codeLength; |
| 220 | } |
| 221 | |
| 222 | public void encodeAndSave(int encodingSizeGuess) throws IOException { |
| 223 | BerByteArrayOutputStream os = new BerByteArrayOutputStream(encodingSizeGuess); |
| 224 | encode(os, false); |
| 225 | code = os.getArray(); |
| 226 | } |
| 227 | |
| 228 | @JsonValue |
| 229 | @Override |
| 230 | public String toString() { |
| 231 | return "" + value; |
| 232 | } |
| 233 | } |