diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/jffs2/compr_rubin.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/jffs2/compr_rubin.c')
-rw-r--r-- | fs/jffs2/compr_rubin.c | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/fs/jffs2/compr_rubin.c b/fs/jffs2/compr_rubin.c new file mode 100644 index 000000000000..450d6624181f --- /dev/null +++ b/fs/jffs2/compr_rubin.c | |||
@@ -0,0 +1,373 @@ | |||
1 | /* | ||
2 | * JFFS2 -- Journalling Flash File System, Version 2. | ||
3 | * | ||
4 | * Copyright (C) 2001, 2002 Red Hat, Inc. | ||
5 | * | ||
6 | * Created by Arjan van de Ven <arjanv@redhat.com> | ||
7 | * | ||
8 | * For licensing information, see the file 'LICENCE' in this directory. | ||
9 | * | ||
10 | * $Id: compr_rubin.c,v 1.20 2004/06/23 16:34:40 havasi Exp $ | ||
11 | * | ||
12 | */ | ||
13 | |||
14 | |||
15 | #include <linux/string.h> | ||
16 | #include <linux/types.h> | ||
17 | #include <linux/jffs2.h> | ||
18 | #include "compr_rubin.h" | ||
19 | #include "histo_mips.h" | ||
20 | #include "compr.h" | ||
21 | |||
22 | static void init_rubin(struct rubin_state *rs, int div, int *bits) | ||
23 | { | ||
24 | int c; | ||
25 | |||
26 | rs->q = 0; | ||
27 | rs->p = (long) (2 * UPPER_BIT_RUBIN); | ||
28 | rs->bit_number = (long) 0; | ||
29 | rs->bit_divider = div; | ||
30 | for (c=0; c<8; c++) | ||
31 | rs->bits[c] = bits[c]; | ||
32 | } | ||
33 | |||
34 | |||
35 | static int encode(struct rubin_state *rs, long A, long B, int symbol) | ||
36 | { | ||
37 | |||
38 | long i0, i1; | ||
39 | int ret; | ||
40 | |||
41 | while ((rs->q >= UPPER_BIT_RUBIN) || ((rs->p + rs->q) <= UPPER_BIT_RUBIN)) { | ||
42 | rs->bit_number++; | ||
43 | |||
44 | ret = pushbit(&rs->pp, (rs->q & UPPER_BIT_RUBIN) ? 1 : 0, 0); | ||
45 | if (ret) | ||
46 | return ret; | ||
47 | rs->q &= LOWER_BITS_RUBIN; | ||
48 | rs->q <<= 1; | ||
49 | rs->p <<= 1; | ||
50 | } | ||
51 | i0 = A * rs->p / (A + B); | ||
52 | if (i0 <= 0) { | ||
53 | i0 = 1; | ||
54 | } | ||
55 | if (i0 >= rs->p) { | ||
56 | i0 = rs->p - 1; | ||
57 | } | ||
58 | i1 = rs->p - i0; | ||
59 | |||
60 | if (symbol == 0) | ||
61 | rs->p = i0; | ||
62 | else { | ||
63 | rs->p = i1; | ||
64 | rs->q += i0; | ||
65 | } | ||
66 | return 0; | ||
67 | } | ||
68 | |||
69 | |||
70 | static void end_rubin(struct rubin_state *rs) | ||
71 | { | ||
72 | |||
73 | int i; | ||
74 | |||
75 | for (i = 0; i < RUBIN_REG_SIZE; i++) { | ||
76 | pushbit(&rs->pp, (UPPER_BIT_RUBIN & rs->q) ? 1 : 0, 1); | ||
77 | rs->q &= LOWER_BITS_RUBIN; | ||
78 | rs->q <<= 1; | ||
79 | } | ||
80 | } | ||
81 | |||
82 | |||
83 | static void init_decode(struct rubin_state *rs, int div, int *bits) | ||
84 | { | ||
85 | init_rubin(rs, div, bits); | ||
86 | |||
87 | /* behalve lower */ | ||
88 | rs->rec_q = 0; | ||
89 | |||
90 | for (rs->bit_number = 0; rs->bit_number++ < RUBIN_REG_SIZE; rs->rec_q = rs->rec_q * 2 + (long) (pullbit(&rs->pp))) | ||
91 | ; | ||
92 | } | ||
93 | |||
94 | static void __do_decode(struct rubin_state *rs, unsigned long p, unsigned long q) | ||
95 | { | ||
96 | register unsigned long lower_bits_rubin = LOWER_BITS_RUBIN; | ||
97 | unsigned long rec_q; | ||
98 | int c, bits = 0; | ||
99 | |||
100 | /* | ||
101 | * First, work out how many bits we need from the input stream. | ||
102 | * Note that we have already done the initial check on this | ||
103 | * loop prior to calling this function. | ||
104 | */ | ||
105 | do { | ||
106 | bits++; | ||
107 | q &= lower_bits_rubin; | ||
108 | q <<= 1; | ||
109 | p <<= 1; | ||
110 | } while ((q >= UPPER_BIT_RUBIN) || ((p + q) <= UPPER_BIT_RUBIN)); | ||
111 | |||
112 | rs->p = p; | ||
113 | rs->q = q; | ||
114 | |||
115 | rs->bit_number += bits; | ||
116 | |||
117 | /* | ||
118 | * Now get the bits. We really want this to be "get n bits". | ||
119 | */ | ||
120 | rec_q = rs->rec_q; | ||
121 | do { | ||
122 | c = pullbit(&rs->pp); | ||
123 | rec_q &= lower_bits_rubin; | ||
124 | rec_q <<= 1; | ||
125 | rec_q += c; | ||
126 | } while (--bits); | ||
127 | rs->rec_q = rec_q; | ||
128 | } | ||
129 | |||
130 | static int decode(struct rubin_state *rs, long A, long B) | ||
131 | { | ||
132 | unsigned long p = rs->p, q = rs->q; | ||
133 | long i0, threshold; | ||
134 | int symbol; | ||
135 | |||
136 | if (q >= UPPER_BIT_RUBIN || ((p + q) <= UPPER_BIT_RUBIN)) | ||
137 | __do_decode(rs, p, q); | ||
138 | |||
139 | i0 = A * rs->p / (A + B); | ||
140 | if (i0 <= 0) { | ||
141 | i0 = 1; | ||
142 | } | ||
143 | if (i0 >= rs->p) { | ||
144 | i0 = rs->p - 1; | ||
145 | } | ||
146 | |||
147 | threshold = rs->q + i0; | ||
148 | symbol = rs->rec_q >= threshold; | ||
149 | if (rs->rec_q >= threshold) { | ||
150 | rs->q += i0; | ||
151 | i0 = rs->p - i0; | ||
152 | } | ||
153 | |||
154 | rs->p = i0; | ||
155 | |||
156 | return symbol; | ||
157 | } | ||
158 | |||
159 | |||
160 | |||
161 | static int out_byte(struct rubin_state *rs, unsigned char byte) | ||
162 | { | ||
163 | int i, ret; | ||
164 | struct rubin_state rs_copy; | ||
165 | rs_copy = *rs; | ||
166 | |||
167 | for (i=0;i<8;i++) { | ||
168 | ret = encode(rs, rs->bit_divider-rs->bits[i],rs->bits[i],byte&1); | ||
169 | if (ret) { | ||
170 | /* Failed. Restore old state */ | ||
171 | *rs = rs_copy; | ||
172 | return ret; | ||
173 | } | ||
174 | byte=byte>>1; | ||
175 | } | ||
176 | return 0; | ||
177 | } | ||
178 | |||
179 | static int in_byte(struct rubin_state *rs) | ||
180 | { | ||
181 | int i, result = 0, bit_divider = rs->bit_divider; | ||
182 | |||
183 | for (i = 0; i < 8; i++) | ||
184 | result |= decode(rs, bit_divider - rs->bits[i], rs->bits[i]) << i; | ||
185 | |||
186 | return result; | ||
187 | } | ||
188 | |||
189 | |||
190 | |||
191 | static int rubin_do_compress(int bit_divider, int *bits, unsigned char *data_in, | ||
192 | unsigned char *cpage_out, uint32_t *sourcelen, uint32_t *dstlen) | ||
193 | { | ||
194 | int outpos = 0; | ||
195 | int pos=0; | ||
196 | struct rubin_state rs; | ||
197 | |||
198 | init_pushpull(&rs.pp, cpage_out, *dstlen * 8, 0, 32); | ||
199 | |||
200 | init_rubin(&rs, bit_divider, bits); | ||
201 | |||
202 | while (pos < (*sourcelen) && !out_byte(&rs, data_in[pos])) | ||
203 | pos++; | ||
204 | |||
205 | end_rubin(&rs); | ||
206 | |||
207 | if (outpos > pos) { | ||
208 | /* We failed */ | ||
209 | return -1; | ||
210 | } | ||
211 | |||
212 | /* Tell the caller how much we managed to compress, | ||
213 | * and how much space it took */ | ||
214 | |||
215 | outpos = (pushedbits(&rs.pp)+7)/8; | ||
216 | |||
217 | if (outpos >= pos) | ||
218 | return -1; /* We didn't actually compress */ | ||
219 | *sourcelen = pos; | ||
220 | *dstlen = outpos; | ||
221 | return 0; | ||
222 | } | ||
223 | #if 0 | ||
224 | /* _compress returns the compressed size, -1 if bigger */ | ||
225 | int jffs2_rubinmips_compress(unsigned char *data_in, unsigned char *cpage_out, | ||
226 | uint32_t *sourcelen, uint32_t *dstlen, void *model) | ||
227 | { | ||
228 | return rubin_do_compress(BIT_DIVIDER_MIPS, bits_mips, data_in, cpage_out, sourcelen, dstlen); | ||
229 | } | ||
230 | #endif | ||
231 | int jffs2_dynrubin_compress(unsigned char *data_in, unsigned char *cpage_out, | ||
232 | uint32_t *sourcelen, uint32_t *dstlen, void *model) | ||
233 | { | ||
234 | int bits[8]; | ||
235 | unsigned char histo[256]; | ||
236 | int i; | ||
237 | int ret; | ||
238 | uint32_t mysrclen, mydstlen; | ||
239 | |||
240 | mysrclen = *sourcelen; | ||
241 | mydstlen = *dstlen - 8; | ||
242 | |||
243 | if (*dstlen <= 12) | ||
244 | return -1; | ||
245 | |||
246 | memset(histo, 0, 256); | ||
247 | for (i=0; i<mysrclen; i++) { | ||
248 | histo[data_in[i]]++; | ||
249 | } | ||
250 | memset(bits, 0, sizeof(int)*8); | ||
251 | for (i=0; i<256; i++) { | ||
252 | if (i&128) | ||
253 | bits[7] += histo[i]; | ||
254 | if (i&64) | ||
255 | bits[6] += histo[i]; | ||
256 | if (i&32) | ||
257 | bits[5] += histo[i]; | ||
258 | if (i&16) | ||
259 | bits[4] += histo[i]; | ||
260 | if (i&8) | ||
261 | bits[3] += histo[i]; | ||
262 | if (i&4) | ||
263 | bits[2] += histo[i]; | ||
264 | if (i&2) | ||
265 | bits[1] += histo[i]; | ||
266 | if (i&1) | ||
267 | bits[0] += histo[i]; | ||
268 | } | ||
269 | |||
270 | for (i=0; i<8; i++) { | ||
271 | bits[i] = (bits[i] * 256) / mysrclen; | ||
272 | if (!bits[i]) bits[i] = 1; | ||
273 | if (bits[i] > 255) bits[i] = 255; | ||
274 | cpage_out[i] = bits[i]; | ||
275 | } | ||
276 | |||
277 | ret = rubin_do_compress(256, bits, data_in, cpage_out+8, &mysrclen, &mydstlen); | ||
278 | if (ret) | ||
279 | return ret; | ||
280 | |||
281 | /* Add back the 8 bytes we took for the probabilities */ | ||
282 | mydstlen += 8; | ||
283 | |||
284 | if (mysrclen <= mydstlen) { | ||
285 | /* We compressed */ | ||
286 | return -1; | ||
287 | } | ||
288 | |||
289 | *sourcelen = mysrclen; | ||
290 | *dstlen = mydstlen; | ||
291 | return 0; | ||
292 | } | ||
293 | |||
294 | static void rubin_do_decompress(int bit_divider, int *bits, unsigned char *cdata_in, | ||
295 | unsigned char *page_out, uint32_t srclen, uint32_t destlen) | ||
296 | { | ||
297 | int outpos = 0; | ||
298 | struct rubin_state rs; | ||
299 | |||
300 | init_pushpull(&rs.pp, cdata_in, srclen, 0, 0); | ||
301 | init_decode(&rs, bit_divider, bits); | ||
302 | |||
303 | while (outpos < destlen) { | ||
304 | page_out[outpos++] = in_byte(&rs); | ||
305 | } | ||
306 | } | ||
307 | |||
308 | |||
309 | int jffs2_rubinmips_decompress(unsigned char *data_in, unsigned char *cpage_out, | ||
310 | uint32_t sourcelen, uint32_t dstlen, void *model) | ||
311 | { | ||
312 | rubin_do_decompress(BIT_DIVIDER_MIPS, bits_mips, data_in, cpage_out, sourcelen, dstlen); | ||
313 | return 0; | ||
314 | } | ||
315 | |||
316 | int jffs2_dynrubin_decompress(unsigned char *data_in, unsigned char *cpage_out, | ||
317 | uint32_t sourcelen, uint32_t dstlen, void *model) | ||
318 | { | ||
319 | int bits[8]; | ||
320 | int c; | ||
321 | |||
322 | for (c=0; c<8; c++) | ||
323 | bits[c] = data_in[c]; | ||
324 | |||
325 | rubin_do_decompress(256, bits, data_in+8, cpage_out, sourcelen-8, dstlen); | ||
326 | return 0; | ||
327 | } | ||
328 | |||
329 | static struct jffs2_compressor jffs2_rubinmips_comp = { | ||
330 | .priority = JFFS2_RUBINMIPS_PRIORITY, | ||
331 | .name = "rubinmips", | ||
332 | .compr = JFFS2_COMPR_DYNRUBIN, | ||
333 | .compress = NULL, /*&jffs2_rubinmips_compress,*/ | ||
334 | .decompress = &jffs2_rubinmips_decompress, | ||
335 | #ifdef JFFS2_RUBINMIPS_DISABLED | ||
336 | .disabled = 1, | ||
337 | #else | ||
338 | .disabled = 0, | ||
339 | #endif | ||
340 | }; | ||
341 | |||
342 | int jffs2_rubinmips_init(void) | ||
343 | { | ||
344 | return jffs2_register_compressor(&jffs2_rubinmips_comp); | ||
345 | } | ||
346 | |||
347 | void jffs2_rubinmips_exit(void) | ||
348 | { | ||
349 | jffs2_unregister_compressor(&jffs2_rubinmips_comp); | ||
350 | } | ||
351 | |||
352 | static struct jffs2_compressor jffs2_dynrubin_comp = { | ||
353 | .priority = JFFS2_DYNRUBIN_PRIORITY, | ||
354 | .name = "dynrubin", | ||
355 | .compr = JFFS2_COMPR_RUBINMIPS, | ||
356 | .compress = jffs2_dynrubin_compress, | ||
357 | .decompress = &jffs2_dynrubin_decompress, | ||
358 | #ifdef JFFS2_DYNRUBIN_DISABLED | ||
359 | .disabled = 1, | ||
360 | #else | ||
361 | .disabled = 0, | ||
362 | #endif | ||
363 | }; | ||
364 | |||
365 | int jffs2_dynrubin_init(void) | ||
366 | { | ||
367 | return jffs2_register_compressor(&jffs2_dynrubin_comp); | ||
368 | } | ||
369 | |||
370 | void jffs2_dynrubin_exit(void) | ||
371 | { | ||
372 | jffs2_unregister_compressor(&jffs2_dynrubin_comp); | ||
373 | } | ||