xref: /freebsd/contrib/xz/src/liblzma/lzma/fastpos_tablegen.c (revision 0b3105a37d7adcadcb720112fed4dc4e8040be99)
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 <sys/types.h>
15 #include <inttypes.h>
16 #include <stdio.h>
17 #include "fastpos.h"
18 
19 
20 int
21 main(void)
22 {
23 	uint8_t fastpos[1 << FASTPOS_BITS];
24 
25 	const uint8_t fast_slots = 2 * FASTPOS_BITS;
26 	uint32_t c = 2;
27 
28 	fastpos[0] = 0;
29 	fastpos[1] = 1;
30 
31 	for (uint8_t slot_fast = 2; slot_fast < fast_slots; ++slot_fast) {
32 		const uint32_t k = 1 << ((slot_fast >> 1) - 1);
33 		for (uint32_t j = 0; j < k; ++j, ++c)
34 			fastpos[c] = slot_fast;
35 	}
36 
37 	printf("/* This file has been automatically generated "
38 			"by fastpos_tablegen.c. */\n\n"
39 			"#include \"common.h\"\n"
40 			"#include \"fastpos.h\"\n\n"
41 			"const uint8_t lzma_fastpos[1 << FASTPOS_BITS] = {");
42 
43 	for (size_t i = 0; i < (1 << FASTPOS_BITS); ++i) {
44 		if (i % 16 == 0)
45 			printf("\n\t");
46 
47 		printf("%3u", (unsigned int)(fastpos[i]));
48 
49 		if (i != (1 << FASTPOS_BITS) - 1)
50 			printf(",");
51 	}
52 
53 	printf("\n};\n");
54 
55 	return 0;
56 }
57