1/*
2 * bzip2 is written by Julian Seward <jseward@bzip.org>.
3 * Adapted for busybox by Denys Vlasenko <vda.linux@googlemail.com>.
4 * See README and LICENSE files in this directory for more information.
5 */
6
7/*-------------------------------------------------------------*/
8/*--- Private header file for the library.                  ---*/
9/*---                                       bzlib_private.h ---*/
10/*-------------------------------------------------------------*/
11
12/* ------------------------------------------------------------------
13This file is part of bzip2/libbzip2, a program and library for
14lossless, block-sorting data compression.
15
16bzip2/libbzip2 version 1.0.4 of 20 December 2006
17Copyright (C) 1996-2006 Julian Seward <jseward@bzip.org>
18
19Please read the WARNING, DISCLAIMER and PATENTS sections in the
20README file.
21
22This program is released under the terms of the license contained
23in the file LICENSE.
24------------------------------------------------------------------ */
25
26/* #include "bzlib.h" */
27
28/*-- General stuff. --*/
29
30typedef unsigned char Bool;
31
32#define True  ((Bool)1)
33#define False ((Bool)0)
34
35#if BZ_LIGHT_DEBUG
36static void bz_assert_fail(int errcode) NORETURN;
37#define AssertH(cond, errcode) \
38do { \
39	if (!(cond)) \
40		bz_assert_fail(errcode); \
41} while (0)
42#else
43#define AssertH(cond, msg) do { } while (0)
44#endif
45
46#if BZ_DEBUG
47#define AssertD(cond, msg) \
48do { \
49	if (!(cond)) \
50		bb_error_msg_and_die("(debug build): internal error %s", msg); \
51} while (0)
52#else
53#define AssertD(cond, msg) do { } while (0)
54#endif
55
56
57/*-- Header bytes. --*/
58
59#define BZ_HDR_B 0x42   /* 'B' */
60#define BZ_HDR_Z 0x5a   /* 'Z' */
61#define BZ_HDR_h 0x68   /* 'h' */
62#define BZ_HDR_0 0x30   /* '0' */
63
64#define BZ_HDR_BZh0 0x425a6830
65
66/*-- Constants for the back end. --*/
67
68#define BZ_MAX_ALPHA_SIZE 258
69#define BZ_MAX_CODE_LEN    23
70
71#define BZ_RUNA 0
72#define BZ_RUNB 1
73
74#define BZ_N_GROUPS 6
75#define BZ_G_SIZE   50
76#define BZ_N_ITERS  4
77
78#define BZ_MAX_SELECTORS (2 + (900000 / BZ_G_SIZE))
79
80
81/*-- Stuff for doing CRCs. --*/
82
83#define BZ_INITIALISE_CRC(crcVar) \
84{ \
85	crcVar = 0xffffffffL; \
86}
87
88#define BZ_FINALISE_CRC(crcVar) \
89{ \
90	crcVar = ~(crcVar); \
91}
92
93#define BZ_UPDATE_CRC(s, crcVar, cha) \
94{ \
95	crcVar = (crcVar << 8) ^ s->crc32table[(crcVar >> 24) ^ ((uint8_t)cha)]; \
96}
97
98
99/*-- States and modes for compression. --*/
100
101#define BZ_M_IDLE      1
102#define BZ_M_RUNNING   2
103#define BZ_M_FLUSHING  3
104#define BZ_M_FINISHING 4
105
106#define BZ_S_OUTPUT    1
107#define BZ_S_INPUT     2
108
109#define BZ_N_RADIX 2
110#define BZ_N_QSORT 12
111#define BZ_N_SHELL 18
112#define BZ_N_OVERSHOOT (BZ_N_RADIX + BZ_N_QSORT + BZ_N_SHELL + 2)
113
114
115/*-- Structure holding all the compression-side stuff. --*/
116
117typedef struct EState {
118	/* pointer back to the struct bz_stream */
119	bz_stream *strm;
120
121	/* mode this stream is in, and whether inputting */
122	/* or outputting data */
123	int32_t  mode;
124	int32_t  state;
125
126	/* remembers avail_in when flush/finish requested */
127/* bbox: not needed, strm->avail_in always has the same value */
128/* commented out with '//#' throughout the code */
129	/* uint32_t avail_in_expect; */
130
131	/* for doing the block sorting */
132	int32_t  origPtr;
133	uint32_t *arr1;
134	uint32_t *arr2;
135	uint32_t *ftab;
136
137	/* aliases for arr1 and arr2 */
138	uint32_t *ptr;
139	uint8_t  *block;
140	uint16_t *mtfv;
141	uint8_t  *zbits;
142
143	/* guess what */
144	uint32_t *crc32table;
145
146	/* run-length-encoding of the input */
147	uint32_t state_in_ch;
148	int32_t  state_in_len;
149
150	/* input and output limits and current posns */
151	int32_t  nblock;
152	int32_t  nblockMAX;
153	int32_t  numZ;
154	int32_t  state_out_pos;
155
156	/* the buffer for bit stream creation */
157	uint32_t bsBuff;
158	int32_t  bsLive;
159
160	/* block and combined CRCs */
161	uint32_t blockCRC;
162	uint32_t combinedCRC;
163
164	/* misc administratium */
165	int32_t  blockNo;
166	int32_t  blockSize100k;
167
168	/* stuff for coding the MTF values */
169	int32_t  nMTF;
170
171	/* map of bytes used in block */
172	int32_t  nInUse;
173	Bool     inUse[256] ALIGNED(sizeof(long));
174	uint8_t  unseqToSeq[256];
175
176	/* stuff for coding the MTF values */
177	int32_t  mtfFreq    [BZ_MAX_ALPHA_SIZE];
178	uint8_t  selector   [BZ_MAX_SELECTORS];
179	uint8_t  selectorMtf[BZ_MAX_SELECTORS];
180
181	uint8_t  len[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
182
183	/* stack-saving measures: these can be local, but they are too big */
184	int32_t  sendMTFValues__code [BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
185	int32_t  sendMTFValues__rfreq[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
186#if CONFIG_BZIP2_FEATURE_SPEED >= 5
187	/* second dimension: only 3 needed; 4 makes index calculations faster */
188	uint32_t sendMTFValues__len_pack[BZ_MAX_ALPHA_SIZE][4];
189#endif
190	int32_t  BZ2_hbMakeCodeLengths__heap  [BZ_MAX_ALPHA_SIZE + 2];
191	int32_t  BZ2_hbMakeCodeLengths__weight[BZ_MAX_ALPHA_SIZE * 2];
192	int32_t  BZ2_hbMakeCodeLengths__parent[BZ_MAX_ALPHA_SIZE * 2];
193
194	int32_t  mainSort__runningOrder[256];
195	int32_t  mainSort__copyStart[256];
196	int32_t  mainSort__copyEnd[256];
197} EState;
198
199
200/*-- compression. --*/
201
202static void
203BZ2_blockSort(EState*);
204
205static void
206BZ2_compressBlock(EState*, int);
207
208static void
209BZ2_bsInitWrite(EState*);
210
211static void
212BZ2_hbAssignCodes(int32_t*, uint8_t*, int32_t, int32_t, int32_t);
213
214static void
215BZ2_hbMakeCodeLengths(EState*, uint8_t*, int32_t*, int32_t, int32_t);
216
217/*-------------------------------------------------------------*/
218/*--- end                                   bzlib_private.h ---*/
219/*-------------------------------------------------------------*/
220