-
Notifications
You must be signed in to change notification settings - Fork 4
/
Copy pathmi_packrec.c
1706 lines (1522 loc) · 50.2 KB
/
mi_packrec.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/* Functions to compressed records */
#include "fulltext.h"
#define IS_CHAR ((uint) 32768) /* Bit if char (not offset) in tree */
/* Some definitions to keep in sync with myisampack.c */
#define HEAD_LENGTH 32 /* Length of fixed header */
#if INT_MAX > 32767
#define BITS_SAVED 32
#define MAX_QUICK_TABLE_BITS 9 /* Because we may shift in 24 bits */
#else
#define BITS_SAVED 16
#define MAX_QUICK_TABLE_BITS 6
#endif
#define get_bit(BU) ((BU)->bits ? \
(BU)->current_byte & ((mi_bit_type) 1 << --(BU)->bits) :\
(fill_buffer(BU), (BU)->bits= BITS_SAVED-1,\
(BU)->current_byte & ((mi_bit_type) 1 << (BITS_SAVED-1))))
#define skip_to_next_byte(BU) ((BU)->bits&=~7)
#define get_bits(BU,count) (((BU)->bits >= count) ? (((BU)->current_byte >> ((BU)->bits-=count)) & mask[count]) : fill_and_get_bits(BU,count))
#define decode_bytes_test_bit(bit) \
if (low_byte & (1 << (7-bit))) \
pos++; \
if (*pos & IS_CHAR) \
{ bits-=(bit+1); break; } \
pos+= *pos
/* Size in uint16 of a Huffman tree for byte compression of 256 byte values. */
#define OFFSET_TABLE_SIZE 512
static uint read_huff_table(MI_BIT_BUFF *bit_buff,MI_DECODE_TREE *decode_tree,
uint16 **decode_table,uchar **intervall_buff,
uint16 *tmp_buff);
static void make_quick_table(uint16 *to_table,uint16 *decode_table,
uint *next_free,uint value,uint bits,
uint max_bits);
static void fill_quick_table(uint16 *table,uint bits, uint max_bits,
uint value);
static uint copy_decode_table(uint16 *to_pos,uint offset,
uint16 *decode_table);
static uint find_longest_bitstream(uint16 *table, uint16 *end);
static void (*get_unpack_function(MI_COLUMNDEF *rec))(MI_COLUMNDEF *field,
MI_BIT_BUFF *buff,
uchar *to,
uchar *end);
static void uf_zerofill_skip_zero(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_skip_zero(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_space_normal(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_space_endspace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end);
static void uf_endspace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_space_endspace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_endspace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_space_prespace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end);
static void uf_prespace_selected(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_space_prespace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_prespace(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_zerofill_normal(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_constant(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_intervall(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_zero(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static void uf_blob(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end);
static void uf_varchar1(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end);
static void uf_varchar2(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end);
static void decode_bytes(MI_COLUMNDEF *rec,MI_BIT_BUFF *bit_buff,
uchar *to,uchar *end);
static uint decode_pos(MI_BIT_BUFF *bit_buff,MI_DECODE_TREE *decode_tree);
static void init_bit_buffer(MI_BIT_BUFF *bit_buff,uchar *buffer,uint length);
static uint fill_and_get_bits(MI_BIT_BUFF *bit_buff,uint count);
static void fill_buffer(MI_BIT_BUFF *bit_buff);
static uint max_bit(uint value);
#ifdef HAVE_MMAP
static uchar *_mi_mempack_get_block_info(MI_INFO *myisam, MI_BIT_BUFF *bit_buff,
MI_BLOCK_INFO *info, uchar **rec_buff_p,
uchar *header);
#endif
static mi_bit_type mask[]=
{
0x00000000,
0x00000001, 0x00000003, 0x00000007, 0x0000000f,
0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
#if BITS_SAVED > 16
0x0001ffff, 0x0003ffff, 0x0007ffff, 0x000fffff,
0x001fffff, 0x003fffff, 0x007fffff, 0x00ffffff,
0x01ffffff, 0x03ffffff, 0x07ffffff, 0x0fffffff,
0x1fffffff, 0x3fffffff, 0x7fffffff, 0xffffffff,
#endif
};
/* Read all packed info, allocate memory and fix field structs */
my_bool _mi_read_pack_info(MI_INFO *info, pbool fix_keys)
{
File file;
int diff_length;
uint i,trees,huff_tree_bits,rec_reflength,length;
uint16 *decode_table,*tmp_buff;
ulong elements,intervall_length;
uchar *disk_cache;
uchar *intervall_buff;
uchar header[HEAD_LENGTH];
MYISAM_SHARE *share=info->s;
MI_BIT_BUFF bit_buff;
DBUG_ENTER("_mi_read_pack_info");
if (myisam_quick_table_bits < 4)
myisam_quick_table_bits=4;
else if (myisam_quick_table_bits > MAX_QUICK_TABLE_BITS)
myisam_quick_table_bits=MAX_QUICK_TABLE_BITS;
file=info->dfile;
my_errno=0;
if (mysql_file_read(file, (uchar*) header, sizeof(header), MYF(MY_NABP)))
{
if (!my_errno)
my_errno=HA_ERR_END_OF_FILE;
goto err0;
}
/* Only the first three bytes of magic number are independent of version. */
if (memcmp((uchar*) header, (uchar*) myisam_pack_file_magic, 3))
{
my_errno=HA_ERR_WRONG_IN_RECORD;
goto err0;
}
share->pack.version= header[3]; /* fourth byte of magic number */
share->pack.header_length= uint4korr(header+4);
share->min_pack_length=(uint) uint4korr(header+8);
share->max_pack_length=(uint) uint4korr(header+12);
elements=uint4korr(header+16);
intervall_length=uint4korr(header+20);
trees=uint2korr(header+24);
share->pack.ref_length=header[26];
rec_reflength=header[27];
diff_length=(int) rec_reflength - (int) share->base.rec_reflength;
if (fix_keys)
share->rec_reflength=rec_reflength;
share->base.min_block_length=share->min_pack_length+1;
if (share->min_pack_length > 254)
share->base.min_block_length+=2;
DBUG_PRINT("info", ("fixed header length: %u", HEAD_LENGTH));
DBUG_PRINT("info", ("total header length: %lu", share->pack.header_length));
DBUG_PRINT("info", ("pack file version: %u", share->pack.version));
DBUG_PRINT("info", ("min pack length: %lu", share->min_pack_length));
DBUG_PRINT("info", ("max pack length: %lu", share->max_pack_length));
DBUG_PRINT("info", ("elements of all trees: %lu", elements));
DBUG_PRINT("info", ("distinct values bytes: %lu", intervall_length));
DBUG_PRINT("info", ("number of code trees: %u", trees));
DBUG_PRINT("info", ("bytes for record lgt: %u", share->pack.ref_length));
DBUG_PRINT("info", ("record pointer length: %u", rec_reflength));
/*
Memory segment #1:
- Decode tree heads
- Distinct column values
*/
if (!(share->decode_trees=(MI_DECODE_TREE*)
my_malloc((uint) (trees*sizeof(MI_DECODE_TREE)+
intervall_length*sizeof(uchar)),
MYF(MY_WME))))
goto err0;
intervall_buff=(uchar*) (share->decode_trees+trees);
/*
Memory segment #2:
- Decode tables
- Quick decode tables
- Temporary decode table
- Compressed data file header cache
This segment will be reallocated after construction of the tables.
*/
length=(uint) (elements*2+trees*(1 << myisam_quick_table_bits));
/*
To keep some algorithms simpler, we accept that they access
bytes beyond the end of the input data. This can affect up to
one byte less than the "word size" size used in this file,
which is BITS_SAVED / 8. To avoid accessing non-allocated
data, we add (BITS_SAVED / 8) - 1 bytes to the buffer size.
*/
if (!(share->decode_tables=(uint16*)
my_malloc((length + OFFSET_TABLE_SIZE) * sizeof(uint16) +
(uint) (share->pack.header_length - sizeof(header) +
(BITS_SAVED / 8) - 1), MYF(MY_WME | MY_ZEROFILL))))
goto err1;
tmp_buff=share->decode_tables+length;
disk_cache= (uchar*) (tmp_buff+OFFSET_TABLE_SIZE);
if (mysql_file_read(file, disk_cache,
(uint) (share->pack.header_length-sizeof(header)),
MYF(MY_NABP)))
goto err2;
huff_tree_bits=max_bit(trees ? trees-1 : 0);
init_bit_buffer(&bit_buff, disk_cache,
(uint) (share->pack.header_length-sizeof(header)));
/* Read new info for each field */
for (i=0 ; i < share->base.fields ; i++)
{
share->rec[i].base_type=(enum en_fieldtype) get_bits(&bit_buff,5);
share->rec[i].pack_type=(uint) get_bits(&bit_buff,6);
share->rec[i].space_length_bits=get_bits(&bit_buff,5);
share->rec[i].huff_tree=share->decode_trees+(uint) get_bits(&bit_buff,
huff_tree_bits);
share->rec[i].unpack=get_unpack_function(share->rec+i);
DBUG_PRINT("info", ("col: %2u type: %2u pack: %u slbits: %2u",
i, share->rec[i].base_type, share->rec[i].pack_type,
share->rec[i].space_length_bits));
}
skip_to_next_byte(&bit_buff);
/*
Construct the decoding tables from the file header. Keep track of
the used memory.
*/
decode_table=share->decode_tables;
for (i=0 ; i < trees ; i++)
if (read_huff_table(&bit_buff,share->decode_trees+i,&decode_table,
&intervall_buff,tmp_buff))
goto err3;
/* Reallocate the decoding tables to the used size. */
decode_table=(uint16*)
my_realloc((uchar*) share->decode_tables,
(uint) ((uchar*) decode_table - (uchar*) share->decode_tables),
MYF(MY_HOLD_ON_ERROR));
/* Fix the table addresses in the tree heads. */
{
my_ptrdiff_t diff=PTR_BYTE_DIFF(decode_table,share->decode_tables);
share->decode_tables=decode_table;
for (i=0 ; i < trees ; i++)
share->decode_trees[i].table=ADD_TO_PTR(share->decode_trees[i].table,
diff, uint16*);
}
/* Fix record-ref-length for keys */
if (fix_keys)
{
for (i=0 ; i < share->base.keys ; i++)
{
MI_KEYDEF *keyinfo= &share->keyinfo[i];
keyinfo->keylength+= (uint16) diff_length;
keyinfo->minlength+= (uint16) diff_length;
keyinfo->maxlength+= (uint16) diff_length;
keyinfo->seg[keyinfo->flag & HA_FULLTEXT ?
FT_SEGS : keyinfo->keysegs].length= (uint16) rec_reflength;
}
if (share->ft2_keyinfo.seg)
{
MI_KEYDEF *ft2_keyinfo= &share->ft2_keyinfo;
ft2_keyinfo->keylength+= (uint16) diff_length;
ft2_keyinfo->minlength+= (uint16) diff_length;
ft2_keyinfo->maxlength+= (uint16) diff_length;
}
}
if (bit_buff.error || bit_buff.pos < bit_buff.end)
goto err3;
DBUG_RETURN(0);
err3:
my_errno=HA_ERR_WRONG_IN_RECORD;
err2:
my_free(share->decode_tables);
err1:
my_free(share->decode_trees);
err0:
DBUG_RETURN(1);
}
/*
Read a huff-code-table from datafile.
SYNOPSIS
read_huff_table()
bit_buff Bit buffer pointing at start of the
decoding table in the file header cache.
decode_tree Pointer to the decode tree head.
decode_table IN/OUT Address of a pointer to the next free space.
intervall_buff IN/OUT Address of a pointer to the next unused values.
tmp_buff Buffer for temporary extraction of a full
decoding table as read from bit_buff.
RETURN
0 OK.
1 Error.
*/
static uint read_huff_table(MI_BIT_BUFF *bit_buff, MI_DECODE_TREE *decode_tree,
uint16 **decode_table, uchar **intervall_buff,
uint16 *tmp_buff)
{
uint min_chr,elements,char_bits,offset_bits,size,intervall_length,table_bits,
next_free_offset;
uint16 *ptr,*end;
DBUG_ENTER("read_huff_table");
if (!get_bits(bit_buff,1))
{
/* Byte value compression. */
min_chr=get_bits(bit_buff,8);
elements=get_bits(bit_buff,9);
char_bits=get_bits(bit_buff,5);
offset_bits=get_bits(bit_buff,5);
intervall_length=0;
ptr=tmp_buff;
DBUG_PRINT("info", ("byte value compression"));
DBUG_PRINT("info", ("minimum byte value: %u", min_chr));
DBUG_PRINT("info", ("number of tree nodes: %u", elements));
DBUG_PRINT("info", ("bits for values: %u", char_bits));
DBUG_PRINT("info", ("bits for tree offsets: %u", offset_bits));
if (elements > 256)
{
DBUG_PRINT("error", ("ERROR: illegal number of tree elements: %u",
elements));
DBUG_RETURN(1);
}
}
else
{
/* Distinct column value compression. */
min_chr=0;
elements=get_bits(bit_buff,15);
intervall_length=get_bits(bit_buff,16);
char_bits=get_bits(bit_buff,5);
offset_bits=get_bits(bit_buff,5);
decode_tree->quick_table_bits=0;
ptr= *decode_table;
DBUG_PRINT("info", ("distinct column value compression"));
DBUG_PRINT("info", ("number of tree nodes: %u", elements));
DBUG_PRINT("info", ("value buffer length: %u", intervall_length));
DBUG_PRINT("info", ("bits for value index: %u", char_bits));
DBUG_PRINT("info", ("bits for tree offsets: %u", offset_bits));
}
size=elements*2-2;
DBUG_PRINT("info", ("tree size in uint16: %u", size));
DBUG_PRINT("info", ("tree size in bytes: %u",
size * (uint) sizeof(uint16)));
for (end=ptr+size ; ptr < end ; ptr++)
{
if (get_bit(bit_buff))
{
*ptr= (uint16) get_bits(bit_buff,offset_bits);
if ((ptr + *ptr >= end) || !*ptr)
{
DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
DBUG_RETURN(1);
}
}
else
*ptr= (uint16) (IS_CHAR + (get_bits(bit_buff,char_bits) + min_chr));
}
skip_to_next_byte(bit_buff);
decode_tree->table= *decode_table;
decode_tree->intervalls= *intervall_buff;
if (! intervall_length)
{
/* Byte value compression. ptr started from tmp_buff. */
/* Find longest Huffman code from begin to end of tree in bits. */
table_bits= find_longest_bitstream(tmp_buff, ptr);
if (table_bits >= OFFSET_TABLE_SIZE)
DBUG_RETURN(1);
if (table_bits > myisam_quick_table_bits)
table_bits=myisam_quick_table_bits;
DBUG_PRINT("info", ("table bits: %u", table_bits));
next_free_offset= (1 << table_bits);
make_quick_table(*decode_table,tmp_buff,&next_free_offset,0,table_bits,
table_bits);
(*decode_table)+= next_free_offset;
decode_tree->quick_table_bits=table_bits;
}
else
{
/* Distinct column value compression. ptr started from *decode_table */
(*decode_table)=end;
/*
get_bits() moves some bytes to a cache buffer in advance. May need
to step back.
*/
bit_buff->pos-= bit_buff->bits/8;
/* Copy the distinct column values from the buffer. */
memcpy(*intervall_buff,bit_buff->pos,(size_t) intervall_length);
(*intervall_buff)+=intervall_length;
bit_buff->pos+=intervall_length;
bit_buff->bits=0;
}
DBUG_RETURN(0);
}
/*
Make a quick_table for faster decoding.
SYNOPSIS
make_quick_table()
to_table Target quick_table and remaining decode table.
decode_table Source Huffman (sub-)tree within tmp_buff.
next_free_offset IN/OUT Next free offset from to_table.
Starts behind quick_table on the top-level.
value Huffman bits found so far.
bits Remaining bits to be collected.
max_bits Total number of bits to collect (table_bits).
DESCRIPTION
The quick table is an array of 16-bit values. There exists one value
for each possible code representable by max_bits (table_bits) bits.
In most cases table_bits is 9. So there are 512 16-bit values.
If the high-order bit (16) is set (IS_CHAR) then the array slot for
this value is a valid Huffman code for a resulting byte value.
The low-order 8 bits (1..8) are the resulting byte value.
Bits 9..14 are the length of the Huffman code for this byte value.
This means so many bits from the input stream were needed to
represent this byte value. The remaining bits belong to later
Huffman codes. This also means that for every Huffman code shorter
than table_bits there are multiple entires in the array, which
differ just in the unused bits.
If the high-order bit (16) is clear (0) then the remaining bits are
the position of the remaining Huffman decode tree segment behind the
quick table.
RETURN
void
*/
static void make_quick_table(uint16 *to_table, uint16 *decode_table,
uint *next_free_offset, uint value, uint bits,
uint max_bits)
{
DBUG_ENTER("make_quick_table");
/*
When down the table to the requested maximum, copy the rest of the
Huffman table.
*/
if (!bits--)
{
/*
Remaining left Huffman tree segment starts behind quick table.
Remaining right Huffman tree segment starts behind left segment.
*/
to_table[value]= (uint16) *next_free_offset;
/*
Re-construct the remaining Huffman tree segment at
next_free_offset in to_table.
*/
*next_free_offset= copy_decode_table(to_table, *next_free_offset,
decode_table);
DBUG_VOID_RETURN;
}
/* Descent on the left side. Left side bits are clear (0). */
if (!(*decode_table & IS_CHAR))
{
/* Not a leaf. Follow the pointer. */
make_quick_table(to_table, decode_table + *decode_table,
next_free_offset, value, bits, max_bits);
}
else
{
/*
A leaf. A Huffman code is complete. Fill the quick_table
array for all possible bit strings starting with this Huffman
code.
*/
fill_quick_table(to_table + value, bits, max_bits, (uint) *decode_table);
}
/* Descent on the right side. Right side bits are set (1). */
decode_table++;
value|= (1 << bits);
if (!(*decode_table & IS_CHAR))
{
/* Not a leaf. Follow the pointer. */
make_quick_table(to_table, decode_table + *decode_table,
next_free_offset, value, bits, max_bits);
}
else
{
/*
A leaf. A Huffman code is complete. Fill the quick_table
array for all possible bit strings starting with this Huffman
code.
*/
fill_quick_table(to_table + value, bits, max_bits, (uint) *decode_table);
}
DBUG_VOID_RETURN;
}
/*
Fill quick_table for all possible values starting with this Huffman code.
SYNOPSIS
fill_quick_table()
table Target quick_table position.
bits Unused bits from max_bits.
max_bits Total number of bits to collect (table_bits).
value The byte encoded by the found Huffman code.
DESCRIPTION
Fill the segment (all slots) of the quick_table array with the
resulting value for the found Huffman code. There are as many slots
as there are combinations representable by the unused bits.
In most cases we use 9 table bits. Assume a 3-bit Huffman code. Then
there are 6 unused bits. Hence we fill 2**6 = 64 slots with the
value.
RETURN
void
*/
static void fill_quick_table(uint16 *table, uint bits, uint max_bits,
uint value)
{
uint16 *end;
DBUG_ENTER("fill_quick_table");
/*
Bits 1..8 of value represent the decoded byte value.
Bits 9..14 become the length of the Huffman code for this byte value.
Bit 16 flags a valid code (IS_CHAR).
*/
value|= (max_bits - bits) << 8 | IS_CHAR;
for (end= table + ((my_ptrdiff_t) 1 << bits); table < end; table++)
{
*table= (uint16) value;
}
DBUG_VOID_RETURN;
}
/*
Reconstruct a decode subtree at the target position.
SYNOPSIS
copy_decode_table()
to_pos Target quick_table and remaining decode table.
offset Next free offset from to_pos.
decode_table Source Huffman subtree within tmp_buff.
NOTE
Pointers in the decode tree are relative to the pointers position.
RETURN
next free offset from to_pos.
*/
static uint copy_decode_table(uint16 *to_pos, uint offset,
uint16 *decode_table)
{
uint prev_offset= offset;
DBUG_ENTER("copy_decode_table");
/* Descent on the left side. */
if (!(*decode_table & IS_CHAR))
{
/* Set a pointer to the next target node. */
to_pos[offset]=2;
/* Copy the left hand subtree there. */
offset=copy_decode_table(to_pos,offset+2,decode_table+ *decode_table);
}
else
{
/* Copy the byte value. */
to_pos[offset]= *decode_table;
/* Step behind this node. */
offset+=2;
}
/* Descent on the right side. */
decode_table++;
if (!(*decode_table & IS_CHAR))
{
/* Set a pointer to the next free target node. */
to_pos[prev_offset+1]=(uint16) (offset-prev_offset-1);
/* Copy the right hand subtree to the entry of that node. */
offset=copy_decode_table(to_pos,offset,decode_table+ *decode_table);
}
else
{
/* Copy the byte value. */
to_pos[prev_offset+1]= *decode_table;
}
DBUG_RETURN(offset);
}
/*
Find the length of the longest Huffman code in this table in bits.
SYNOPSIS
find_longest_bitstream()
table Code (sub-)table start.
end End of code table.
IMPLEMENTATION
Recursively follow the branch(es) of the code pair on every level of
the tree until two byte values (and no branch) are found. Add one to
each level when returning back from each recursion stage.
'end' is used for error checking only. A clean tree terminates
before reaching 'end'. Hence the exact value of 'end' is not too
important. However having it higher than necessary could lead to
misbehaviour should 'next' jump into the dirty area.
RETURN
length Length of longest Huffman code in bits.
>= OFFSET_TABLE_SIZE Error, broken tree. It does not end before 'end'.
*/
static uint find_longest_bitstream(uint16 *table, uint16 *end)
{
uint length= 1;
uint length2;
if (!(*table & IS_CHAR))
{
uint16 *next= table + *table;
if (next > end || next == table)
{
DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
return OFFSET_TABLE_SIZE;
}
length= find_longest_bitstream(next, end) + 1;
}
table++;
if (!(*table & IS_CHAR))
{
uint16 *next= table + *table;
if (next > end || next == table)
{
DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
return OFFSET_TABLE_SIZE;
}
length2= find_longest_bitstream(next, end) + 1;
length= MY_MAX(length, length2);
}
return length;
}
/*
Read record from datafile.
SYNOPSIS
_mi_read_pack_record()
info A pointer to MI_INFO.
filepos File offset of the record.
buf RETURN The buffer to receive the record.
RETURN
0 on success
HA_ERR_WRONG_IN_RECORD or -1 on error
*/
int _mi_read_pack_record(MI_INFO *info, my_off_t filepos, uchar *buf)
{
MI_BLOCK_INFO block_info;
File file;
DBUG_ENTER("mi_read_pack_record");
if (filepos == HA_OFFSET_ERROR)
DBUG_RETURN(-1); /* _search() didn't find record */
file=info->dfile;
if (_mi_pack_get_block_info(info, &info->bit_buff, &block_info,
&info->rec_buff, file, filepos))
goto err;
if (mysql_file_read(file, (uchar*) info->rec_buff + block_info.offset,
block_info.rec_len - block_info.offset, MYF(MY_NABP)))
goto panic;
info->update|= HA_STATE_AKTIV;
DBUG_RETURN(_mi_pack_rec_unpack(info, &info->bit_buff, buf,
info->rec_buff, block_info.rec_len));
panic:
my_errno=HA_ERR_WRONG_IN_RECORD;
err:
DBUG_RETURN(-1);
}
int _mi_pack_rec_unpack(register MI_INFO *info, MI_BIT_BUFF *bit_buff,
register uchar *to, uchar *from, ulong reclength)
{
uchar *end_field;
reg3 MI_COLUMNDEF *end;
MI_COLUMNDEF *current_field;
MYISAM_SHARE *share=info->s;
DBUG_ENTER("_mi_pack_rec_unpack");
init_bit_buffer(bit_buff, (uchar*) from, reclength);
for (current_field=share->rec, end=current_field+share->base.fields ;
current_field < end ;
current_field++,to=end_field)
{
end_field=to+current_field->length;
(*current_field->unpack)(current_field, bit_buff, (uchar*) to,
(uchar*) end_field);
}
if (!bit_buff->error &&
bit_buff->pos - bit_buff->bits / 8 == bit_buff->end)
DBUG_RETURN(0);
info->update&= ~HA_STATE_AKTIV;
DBUG_RETURN(my_errno=HA_ERR_WRONG_IN_RECORD);
} /* _mi_pack_rec_unpack */
/* Return function to unpack field */
static void (*get_unpack_function(MI_COLUMNDEF *rec))
(MI_COLUMNDEF *, MI_BIT_BUFF *, uchar *, uchar *)
{
switch (rec->base_type) {
case FIELD_SKIP_ZERO:
if (rec->pack_type & PACK_TYPE_ZERO_FILL)
return &uf_zerofill_skip_zero;
return &uf_skip_zero;
case FIELD_NORMAL:
if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
return &uf_space_normal;
if (rec->pack_type & PACK_TYPE_ZERO_FILL)
return &uf_zerofill_normal;
return &decode_bytes;
case FIELD_SKIP_ENDSPACE:
if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
{
if (rec->pack_type & PACK_TYPE_SELECTED)
return &uf_space_endspace_selected;
return &uf_space_endspace;
}
if (rec->pack_type & PACK_TYPE_SELECTED)
return &uf_endspace_selected;
return &uf_endspace;
case FIELD_SKIP_PRESPACE:
if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
{
if (rec->pack_type & PACK_TYPE_SELECTED)
return &uf_space_prespace_selected;
return &uf_space_prespace;
}
if (rec->pack_type & PACK_TYPE_SELECTED)
return &uf_prespace_selected;
return &uf_prespace;
case FIELD_CONSTANT:
return &uf_constant;
case FIELD_INTERVALL:
return &uf_intervall;
case FIELD_ZERO:
case FIELD_CHECK:
return &uf_zero;
case FIELD_BLOB:
return &uf_blob;
case FIELD_VARCHAR:
if (rec->length <= 256) /* 255 + 1 byte length */
return &uf_varchar1;
return &uf_varchar2;
case FIELD_LAST:
default:
return 0; /* This should never happend */
}
}
/* The different functions to unpack a field */
static void uf_zerofill_skip_zero(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end)
{
if (get_bit(bit_buff))
memset(to, 0, (end-to));
else
{
end-=rec->space_length_bits;
decode_bytes(rec,bit_buff,to,end);
memset(end, 0, rec->space_length_bits);
}
}
static void uf_skip_zero(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
uchar *end)
{
if (get_bit(bit_buff))
memset(to, 0, (end-to));
else
decode_bytes(rec,bit_buff,to,end);
}
static void uf_space_normal(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
uchar *end)
{
if (get_bit(bit_buff))
memset(to, ' ', end - to);
else
decode_bytes(rec,bit_buff,to,end);
}
static void uf_space_endspace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end)
{
uint spaces;
if (get_bit(bit_buff))
memset(to, ' ', end-to);
else
{
if (get_bit(bit_buff))
{
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
if (to+spaces != end)
decode_bytes(rec,bit_buff,to,end-spaces);
memset(end-spaces, ' ', spaces);
}
else
decode_bytes(rec,bit_buff,to,end);
}
}
static void uf_endspace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end)
{
uint spaces;
if (get_bit(bit_buff))
{
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
if (to+spaces != end)
decode_bytes(rec,bit_buff,to,end-spaces);
memset(end - spaces, ' ', spaces);
}
else
decode_bytes(rec,bit_buff,to,end);
}
static void uf_space_endspace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
uchar *end)
{
uint spaces;
if (get_bit(bit_buff))
memset(to, ' ', end - to);
else
{
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
if (to+spaces != end)
decode_bytes(rec,bit_buff,to,end-spaces);
memset(end - spaces, ' ', spaces);
}
}
static void uf_endspace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
uchar *end)
{
uint spaces;
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
if (to+spaces != end)
decode_bytes(rec,bit_buff,to,end-spaces);
memset(end - spaces, ' ', spaces);
}
static void uf_space_prespace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end)
{
uint spaces;
if (get_bit(bit_buff))
memset(to, ' ', end - to);
else
{
if (get_bit(bit_buff))
{
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
memset(to, ' ', spaces);
if (to+spaces != end)
decode_bytes(rec,bit_buff,to+spaces,end);
}
else
decode_bytes(rec,bit_buff,to,end);
}
}
static void uf_prespace_selected(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff,
uchar *to, uchar *end)
{
uint spaces;
if (get_bit(bit_buff))
{
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
memset(to, ' ', spaces);
if (to+spaces != end)
decode_bytes(rec,bit_buff,to+spaces,end);
}
else
decode_bytes(rec,bit_buff,to,end);
}
static void uf_space_prespace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
uchar *end)
{
uint spaces;
if (get_bit(bit_buff))
memset(to, ' ', end-to);
else
{
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
memset(to, ' ', spaces);
if (to+spaces != end)
decode_bytes(rec,bit_buff,to+spaces,end);
}
}
static void uf_prespace(MI_COLUMNDEF *rec, MI_BIT_BUFF *bit_buff, uchar *to,
uchar *end)
{
uint spaces;
if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
{
bit_buff->error=1;
return;
}
memset(to, ' ', spaces);
if (to+spaces != end)
decode_bytes(rec,bit_buff,to+spaces,end);