xref: /freebsd/contrib/xz/src/liblzma/lzma/fastpos_tablegen.c (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file       fastpos_tablegen.c
4 /// \brief      Generates the lzma_fastpos[] lookup table
5 ///
6 //  Authors:    Igor Pavlov
7 //              Lasse Collin
8 //
9 //  This file has been put into the public domain.
10 //  You can do whatever you want with this file.
11 //
12 ///////////////////////////////////////////////////////////////////////////////
13 
14 #include <inttypes.h>
15 #include <stdio.h>
16 #include "fastpos.h"
17 
18 
19 int
20 main(void)
21 {
22 	uint8_t fastpos[1 << FASTPOS_BITS];
23 
24 	const uint8_t fast_slots = 2 * FASTPOS_BITS;
25 	uint32_t c = 2;
26 
27 	fastpos[0] = 0;
28 	fastpos[1] = 1;
29 
30 	for (uint8_t slot_fast = 2; slot_fast < fast_slots; ++slot_fast) {
31 		const uint32_t k = 1 << ((slot_fast >> 1) - 1);
32 		for (uint32_t j = 0; j < k; ++j, ++c)
33 			fastpos[c] = slot_fast;
34 	}
35 
36 	printf("/* This file has been automatically generated "
37 			"by fastpos_tablegen.c. */\n\n"
38 			"#include \"common.h\"\n"
39 			"#include \"fastpos.h\"\n\n"
40 			"const uint8_t lzma_fastpos[1 << FASTPOS_BITS] = {");
41 
42 	for (size_t i = 0; i < (1 << FASTPOS_BITS); ++i) {
43 		if (i % 16 == 0)
44 			printf("\n\t");
45 
46 		printf("%3u", (unsigned int)(fastpos[i]));
47 
48 		if (i != (1 << FASTPOS_BITS) - 1)
49 			printf(",");
50 	}
51 
52 	printf("\n};\n");
53 
54 	return 0;
55 }
56