J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package com.sun.java.util.jar.pack; |
| 27 | |
| 28 | import java.util.*; |
| 29 | import java.io.*; |
| 30 | |
| 31 | /** |
| 32 | * Adaptive coding. |
| 33 | * See the section "Adaptive Encodings" in the Pack200 spec. |
| 34 | * @author John Rose |
| 35 | */ |
| 36 | class AdaptiveCoding implements Constants, CodingMethod { |
| 37 | CodingMethod headCoding; |
| 38 | int headLength; |
| 39 | CodingMethod tailCoding; |
| 40 | |
| 41 | public AdaptiveCoding(int headLength, CodingMethod headCoding, CodingMethod tailCoding) { |
| 42 | assert(isCodableLength(headLength)); |
| 43 | this.headLength = headLength; |
| 44 | this.headCoding = headCoding; |
| 45 | this.tailCoding = tailCoding; |
| 46 | } |
| 47 | |
| 48 | public void setHeadCoding(CodingMethod headCoding) { |
| 49 | this.headCoding = headCoding; |
| 50 | } |
| 51 | public void setHeadLength(int headLength) { |
| 52 | assert(isCodableLength(headLength)); |
| 53 | this.headLength = headLength; |
| 54 | } |
| 55 | public void setTailCoding(CodingMethod tailCoding) { |
| 56 | this.tailCoding = tailCoding; |
| 57 | } |
| 58 | |
| 59 | public boolean isTrivial() { |
| 60 | return headCoding == tailCoding; |
| 61 | } |
| 62 | |
| 63 | // CodingMethod methods. |
| 64 | public void writeArrayTo(OutputStream out, int[] a, int start, int end) throws IOException { |
| 65 | writeArray(this, out, a, start, end); |
| 66 | } |
| 67 | // writeArrayTo must be coded iteratively, not recursively: |
| 68 | private static void writeArray(AdaptiveCoding run, OutputStream out, int[] a, int start, int end) throws IOException { |
| 69 | for (;;) { |
| 70 | int mid = start+run.headLength; |
| 71 | assert(mid <= end); |
| 72 | run.headCoding.writeArrayTo(out, a, start, mid); |
| 73 | start = mid; |
| 74 | if (run.tailCoding instanceof AdaptiveCoding) { |
| 75 | run = (AdaptiveCoding) run.tailCoding; |
| 76 | continue; |
| 77 | } |
| 78 | break; |
| 79 | } |
| 80 | run.tailCoding.writeArrayTo(out, a, start, end); |
| 81 | } |
| 82 | |
| 83 | public void readArrayFrom(InputStream in, int[] a, int start, int end) throws IOException { |
| 84 | readArray(this, in, a, start, end); |
| 85 | } |
| 86 | private static void readArray(AdaptiveCoding run, InputStream in, int[] a, int start, int end) throws IOException { |
| 87 | for (;;) { |
| 88 | int mid = start+run.headLength; |
| 89 | assert(mid <= end); |
| 90 | run.headCoding.readArrayFrom(in, a, start, mid); |
| 91 | start = mid; |
| 92 | if (run.tailCoding instanceof AdaptiveCoding) { |
| 93 | run = (AdaptiveCoding) run.tailCoding; |
| 94 | continue; |
| 95 | } |
| 96 | break; |
| 97 | } |
| 98 | run.tailCoding.readArrayFrom(in, a, start, end); |
| 99 | } |
| 100 | |
| 101 | public static final int KX_MIN = 0; |
| 102 | public static final int KX_MAX = 3; |
| 103 | public static final int KX_LG2BASE = 4; |
| 104 | public static final int KX_BASE = 16; |
| 105 | |
| 106 | public static final int KB_MIN = 0x00; |
| 107 | public static final int KB_MAX = 0xFF; |
| 108 | public static final int KB_OFFSET = 1; |
| 109 | public static final int KB_DEFAULT = 3; |
| 110 | |
| 111 | static int getKXOf(int K) { |
| 112 | for (int KX = KX_MIN; KX <= KX_MAX; KX++) { |
| 113 | if (((K - KB_OFFSET) & ~KB_MAX) == 0) |
| 114 | return KX; |
| 115 | K >>>= KX_LG2BASE; |
| 116 | } |
| 117 | return -1; |
| 118 | } |
| 119 | |
| 120 | static int getKBOf(int K) { |
| 121 | int KX = getKXOf(K); |
| 122 | if (KX < 0) return -1; |
| 123 | K >>>= (KX * KX_LG2BASE); |
| 124 | return K-1; |
| 125 | } |
| 126 | |
| 127 | static int decodeK(int KX, int KB) { |
| 128 | assert(KX_MIN <= KX && KX <= KX_MAX); |
| 129 | assert(KB_MIN <= KB && KB <= KB_MAX); |
| 130 | return (KB+KB_OFFSET) << (KX * KX_LG2BASE); |
| 131 | } |
| 132 | |
| 133 | static int getNextK(int K) { |
| 134 | if (K <= 0) return 1; // 1st K value |
| 135 | int KX = getKXOf(K); |
| 136 | if (KX < 0) return Integer.MAX_VALUE; |
| 137 | // This is the increment we expect to apply: |
| 138 | int unit = 1 << (KX * KX_LG2BASE); |
| 139 | int mask = KB_MAX << (KX * KX_LG2BASE); |
| 140 | int K1 = K + unit; |
| 141 | K1 &= ~(unit-1); // cut off stray low-order bits |
| 142 | if (((K1 - unit) & ~mask) == 0) { |
| 143 | assert(getKXOf(K1) == KX); |
| 144 | return K1; |
| 145 | } |
| 146 | if (KX == KX_MAX) return Integer.MAX_VALUE; |
| 147 | KX += 1; |
| 148 | int unit2 = 1 << (KX * KX_LG2BASE); |
| 149 | int mask2 = KB_MAX << (KX * KX_LG2BASE); |
| 150 | K1 |= (mask & ~mask2); |
| 151 | K1 += unit; |
| 152 | assert(getKXOf(K1) == KX); |
| 153 | return K1; |
| 154 | } |
| 155 | |
| 156 | // Is K of the form ((KB:[0..255])+1) * 16^(KX:{0..3])? |
| 157 | public static boolean isCodableLength(int K) { |
| 158 | int KX = getKXOf(K); |
| 159 | if (KX < 0) return false; |
| 160 | int unit = 1 << (KX * KX_LG2BASE); |
| 161 | int mask = KB_MAX << (KX * KX_LG2BASE); |
| 162 | return ((K - unit) & ~mask) == 0; |
| 163 | } |
| 164 | |
| 165 | public byte[] getMetaCoding(Coding dflt) { |
| 166 | //assert(!isTrivial()); // can happen |
| 167 | // See the isCodableLength restriction in CodingChooser. |
| 168 | ByteArrayOutputStream bytes = new ByteArrayOutputStream(10); |
| 169 | try { |
| 170 | makeMetaCoding(this, dflt, bytes); |
| 171 | } catch (IOException ee) { |
| 172 | throw new RuntimeException(ee); |
| 173 | } |
| 174 | return bytes.toByteArray(); |
| 175 | } |
| 176 | private static void makeMetaCoding(AdaptiveCoding run, Coding dflt, |
| 177 | ByteArrayOutputStream bytes) |
| 178 | throws IOException { |
| 179 | for (;;) { |
| 180 | CodingMethod headCoding = run.headCoding; |
| 181 | int headLength = run.headLength; |
| 182 | CodingMethod tailCoding = run.tailCoding; |
| 183 | int K = headLength; |
| 184 | assert(isCodableLength(K)); |
| 185 | int ADef = (headCoding == dflt)?1:0; |
| 186 | int BDef = (tailCoding == dflt)?1:0; |
| 187 | if (ADef+BDef > 1) BDef = 0; // arbitrary choice |
| 188 | int ABDef = 1*ADef + 2*BDef; |
| 189 | assert(ABDef < 3); |
| 190 | int KX = getKXOf(K); |
| 191 | int KB = getKBOf(K); |
| 192 | assert(decodeK(KX, KB) == K); |
| 193 | int KBFlag = (KB != KB_DEFAULT)?1:0; |
| 194 | bytes.write(_meta_run + KX + 4*KBFlag + 8*ABDef); |
| 195 | if (KBFlag != 0) bytes.write(KB); |
| 196 | if (ADef == 0) bytes.write(headCoding.getMetaCoding(dflt)); |
| 197 | if (tailCoding instanceof AdaptiveCoding) { |
| 198 | run = (AdaptiveCoding) tailCoding; |
| 199 | continue; // tail call, to avoid deep stack recursion |
| 200 | } |
| 201 | if (BDef == 0) bytes.write(tailCoding.getMetaCoding(dflt)); |
| 202 | break; |
| 203 | } |
| 204 | } |
| 205 | public static int parseMetaCoding(byte[] bytes, int pos, Coding dflt, CodingMethod res[]) { |
| 206 | int op = bytes[pos++] & 0xFF; |
| 207 | if (op < _meta_run || op >= _meta_pop) return pos-1; // backup |
| 208 | AdaptiveCoding prevc = null; |
| 209 | for (boolean keepGoing = true; keepGoing; ) { |
| 210 | keepGoing = false; |
| 211 | assert(op >= _meta_run); |
| 212 | op -= _meta_run; |
| 213 | int KX = op % 4; |
| 214 | int KBFlag = (op / 4) % 2; |
| 215 | int ABDef = (op / 8); |
| 216 | assert(ABDef < 3); |
| 217 | int ADef = (ABDef & 1); |
| 218 | int BDef = (ABDef & 2); |
| 219 | CodingMethod[] ACode = {dflt}, BCode = {dflt}; |
| 220 | int KB = KB_DEFAULT; |
| 221 | if (KBFlag != 0) |
| 222 | KB = bytes[pos++] & 0xFF; |
| 223 | if (ADef == 0) { |
| 224 | pos = BandStructure.parseMetaCoding(bytes, pos, dflt, ACode); |
| 225 | } |
| 226 | if (BDef == 0 && |
| 227 | ((op = bytes[pos] & 0xFF) >= _meta_run) && op < _meta_pop) { |
| 228 | pos++; |
| 229 | keepGoing = true; |
| 230 | } else if (BDef == 0) { |
| 231 | pos = BandStructure.parseMetaCoding(bytes, pos, dflt, BCode); |
| 232 | } |
| 233 | AdaptiveCoding newc = new AdaptiveCoding(decodeK(KX, KB), |
| 234 | ACode[0], BCode[0]); |
| 235 | if (prevc == null) { |
| 236 | res[0] = newc; |
| 237 | } else { |
| 238 | prevc.tailCoding = newc; |
| 239 | } |
| 240 | prevc = newc; |
| 241 | } |
| 242 | return pos; |
| 243 | } |
| 244 | |
| 245 | private String keyString(CodingMethod m) { |
| 246 | if (m instanceof Coding) |
| 247 | return ((Coding)m).keyString(); |
| 248 | return m.toString(); |
| 249 | } |
| 250 | public String toString() { |
| 251 | StringBuffer res = new StringBuffer(20); |
| 252 | AdaptiveCoding run = this; |
| 253 | res.append("run("); |
| 254 | for (;;) { |
| 255 | res.append(run.headLength).append("*"); |
| 256 | res.append(keyString(run.headCoding)); |
| 257 | if (run.tailCoding instanceof AdaptiveCoding) { |
| 258 | run = (AdaptiveCoding) run.tailCoding; |
| 259 | res.append(" "); |
| 260 | continue; |
| 261 | } |
| 262 | break; |
| 263 | } |
| 264 | res.append(" **").append(keyString(run.tailCoding)); |
| 265 | res.append(")"); |
| 266 | return res.toString(); |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | public static void main(String av[]) { |
| 271 | int[][] samples = { |
| 272 | {1,2,3,4,5}, |
| 273 | {254,255,256,256+1*16,256+2*16}, |
| 274 | {0xfd,0xfe,0xff,0x100,0x110,0x120,0x130}, |
| 275 | {0xfd0,0xfe0,0xff0,0x1000,0x1100,0x1200,0x1300}, |
| 276 | {0xfd00,0xfe00,0xff00,0x10000,0x11000,0x12000,0x13000}, |
| 277 | {0xfd000,0xfe000,0xff000,0x100000} |
| 278 | }; |
| 279 | for (int i = 0; i < samples.length; i++) { |
| 280 | for (int j = 0; j < samples[i].length; j++) { |
| 281 | int K = samples[i][j]; |
| 282 | int KX = getKXOf(K); |
| 283 | int KB = getKBOf(K); |
| 284 | System.out.println("K="+Integer.toHexString(K)+ |
| 285 | " KX="+KX+" KB="+KB); |
| 286 | assert(isCodableLength(K)); |
| 287 | assert(K == decodeK(KX, KB)); |
| 288 | if (j == 0) continue; |
| 289 | int K1 = samples[i][j-1]; |
| 290 | assert(K == getNextK(K1)); |
| 291 | } |
| 292 | } |
| 293 | } |
| 294 | //*/ |
| 295 | |
| 296 | } |