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This appendix gives statistics for some of the compression programs found in this book. The data sets used to test the compression where identical to the ones I used when judging the 1991 Dr. Dobb’s Journal Data Compression Contest. The results of that contest can be found in the November 1991 issue of Dr. Dobb’s Journal.
The compression and expansion speeds given here should be taken with a grain of salt. First of all, no attempt was made to optimize these programs. Secondly, some variation will be seen depending on what compiler was used to build the executable. Most of the executables were built using Borland C++, but in a few cases, expanded memory requirements let me to use Zortech C++ with either the 286 or 386 DOS Extender.
| Compression Ratios | ||||
|---|---|---|---|---|
| Graphics | Executables | Text Files | Overall | |
| HUFF.C Chapter 3 | ||||
| Huffman Coding | 27.22 | 24.79 | 40.38 | 31.04 |
| AHUFF.C Chapter4 | ||||
| Adaptive Huffman | 32.59 | 26.69 | 40.72 | 33.27 |
| ARITH.C Chapter 5 | ||||
| Arithmetic Coding | 27.78 | 25.25 | 40.81 | 31.51 |
| ARITHN.C Chapter 6 | ||||
| Order = 1 | 61.66 | 44.74 | 59.60 | 54.49 |
| ARITHN.C Chapter 6 (1) | ||||
| Order = 2 | 59.85 | 50.47 | 68.43 | 59.37 |
| ARITHN.C Chapter 6 (1) | ||||
| Order = 3 | 58.51 | 51.55 | 71.86 | 60.67 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/4 | 43.45 | 41.44 | 58.83 | 48.22 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 13/4 | 44.57 | 42.56 | 60.91 | 49.69 |
| LZSS.C Chapter 8 (3) | ||||
| Index/Length = 14/4 | 44.71 | 42.32 | 61.10 | 49.70 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/3 | 42.83 | 40.38 | 57.27 | 47.10 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/5 | 43.91 | 42.31 | 59.21 | 48.81 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/8 | 40.60 | 39.60 | 54.67 | 45.29 |
| LZW15V.C Chapter 9 | ||||
| 15 bit variable LZW | 48.44 | 36.15 | 58.28 | 47.31 |
| LZW15V.C Chapter 9 | ||||
| 14 bit variable LZW | 48.23 | 36.27 | 57.76 | 47.11 |
| LZW15V.C Chapter 9 | ||||
| 13 bit variable LZW | 47.76 | 36.34 | 56.71 | 46.65 |
| LZW15V.C Chapter 9 | ||||
| 12 bit variable LZW | 46.78 | 36.61 | 54.82 | 45.81 |
| LZW12.C Chapter 9 | ||||
| 12 bit fixed LZW | 20.61 | 15.07 | 50.32 | 29.20 |
| HUFF.C Chapter 3 | ||||
| Huffman Coding | 15273 | 13306 | 13353 | 13835 |
| AHUFF.C Chapter 4 | ||||
| Adaptive Huffman | 7553 | 6200 | 7523 | 7028 |
| ARITH.C Chapter 5 | ||||
| Arithmetic Coding | 4616 | 4667 | 4474 | 4584 |
| ARITHN.C Chapter 6 | ||||
| Order = 1 | 804 | 395 | 953 | 702 |
| ARITHN.C Chapter 6 (1) | ||||
| Order = 2 | 929 | 462 | 1158 | 834 |
| ARITHN.C Chapter 6 (1) | ||||
| Order = 3 | 975 | 483 | 1206 | 871 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/4 | 3657 | 4159 | 3165 | 3671 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 13/4 | 3268 | 3853 | 2839 | 3336 |
| LZSS.C Chapter 8 (3) | ||||
| Index/Length = 14/4 | 3082 | 3832 | 2563 | 3180 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/3 | 4093 | 4392 | 3594 | 4027 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/5 | 2942 | 3764 | 2773 | 3194 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/8 | 1831 | 1460 | 2411 | 1899 |
| LZW15V.C Chapter 9 | ||||
| 15 bit variable LZW | 14913 | 11744 | 13332 | 13140 |
| LZW15V.C Chapter 9 | ||||
| 14 bit variable LZW | 14850 | 11332 | 12783 | 12769 |
| LZW15V.C Chapter 9 | ||||
| 13 bit variable LZW | 14256 | 10904 | 12241 | 12257 |
| LZW15V.C Chapter 9 | ||||
| 12 bit variable LZW | 13669 | 10320 | 11432 | 11591 |
| LZW12.C Chapter 9 | ||||
| 12 bit fixed LZW | 13106 | 11057 | 14379 | 12786 |
| Expansion Rates | ||||
|---|---|---|---|---|
| Graphics | Executables | Text Files | Overall | |
| HUFF.C Chapter 3 | ||||
| Huffman Coding | 12428 | 10892 | 12560 | 11891 |
| AHUFF.C Chapter 4 | ||||
| Adaptive Huffman | 7366 | 6141 | 7755 | 7041 |
| ARITH.C Chapter 5 | ||||
| Arithmetic Coding | 2320 | 2205 | 2074 | 2188 |
| ARITHN.C Chapter 6 | ||||
| Order = 1 | 793 | 405 | 944 | 700 |
| ARITHN.C Chapter 6 (1) | ||||
| Order = 2 | 905 | 472 | 1136 | 824 |
| ARITHN.C Chapter 6 (1) | ||||
| Order = 3 | 946 | 492 | 1173 | 855 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/4 | 18622 | 16526 | 17424 | 17394 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 13/4 | 18899 | 16716 | 17798 | 17673 |
| LZSS.C Chapter 8 (3) | ||||
| Index/Length = 14/4 | 30334 | 25120 | 27120 | 27196 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/3 | 18248 | 16572 | 16756 | 17074 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/5 | 18680 | 16674 | 17266 | 17409 |
| LZSS.C Chapter 8 | ||||
| Index/Length = 12/8 | 18113 | 16230 | 16673 | 16879 |
| LZW15V.C Chapter 9 | ||||
| 15 bit variable LZW | 15167 | 11986 | 13077 | 13206 |
| LZW15V.C Chapter 9 | ||||
| 14 bit variable LZW | 14942 | 11804 | 12911 | 13018 |
| LZW15V.C Chapter 9 | ||||
| 13 bit variable LZW | 14445 | 11462 | 12495 | 12609 |
| LZW15V.C Chapter 9 | ||||
| 12 bit variable LZW | 13567 | 10893 | 11608 | 11845 |
| LZW12.C Chapter 9 | ||||
| 12 bit fixed LZW | 15326 | 13978 | 15705 | 14950 |
Notes:
(1) Built with Zortech’s 286 DOS Extender, so as to access all available extended memory. Higher order models can use megabytes of memory.(2) Built with Zortech’s 386 DOS Extender. One of the arrays in the program was larger than 64K, and this was an easy way to rebuild the code without using MS-DOS based “huge” pointers.
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