2 * Copyright (C) 1994, Index Data I/S
4 * Sebastian Hammer, Adam Dickmeiss
7 * Revision 1.5 1994-09-27 20:03:36 quinn
8 * Seems relatively bug-free.
10 * Revision 1.4 1994/09/26 17:05:54 quinn
13 * Revision 1.3 1994/09/26 16:08:42 quinn
14 * Most of the functionality in place.
16 * Revision 1.2 1994/09/14 13:10:35 quinn
19 * Revision 1.1 1994/09/12 08:02:07 quinn
29 #include "../isam/memory.h"
30 #include "../isam/physical.h"
32 #define IS_MAX_BLOCKTYPES 4
33 #define IS_MAX_RECORD 512
34 #define IS_DEF_REPACK_PERCENT "30" /* how much relative change before repack */
36 typedef unsigned int SYSNO; /* should be somewhere else */
39 * Description of a blocktype (part of an isam file)
41 typedef struct isam_blocktype
43 BFile bf; /* blocked file */
45 int first_block; /* position of first data block */
46 int max_keys_block; /* max num of keys per block */
47 int max_keys_block0; /* max num of keys in first block */
48 int nice_keys_block; /* nice number of keys per block */
49 int max_keys; /* max number of keys per table */
50 int freelist; /* first free block */
51 int top; /* first unused block */
52 int index; /* placeholder. Always 0. */
53 char *dbuf; /* buffer for use in I/O operations */
57 * Handle to an open isam complex.
59 typedef struct isam_struct
61 isam_blocktype types[IS_MAX_BLOCKTYPES]; /* block_types used in this file */
62 int num_types; /* number of block types used */
64 int keysize; /* size of the keys (records) used */
65 int repack; /* how many percent to grow before repack */
66 int (*cmp)(const void *k1, const void *k2); /* compare function */
69 typedef struct ispt_struct
71 struct is_mtable *tab;
72 struct ispt_struct *next; /* freelist */
75 #define is_type(x) ((x) & 3) /* type part of position */
76 #define is_block(x) ((x) >> 2) /* block # part of position */
78 #define is_keysize(is) ((is)->keysize)
82 *******************************************************************
88 ISAM is_open(const char *name, int writeflag);
93 int is_close(ISAM is);
96 * Locate a table of keys in an isam file. The ISPT is an individual
97 * position marker for that table.
99 ISPT is_position(ISAM is, ISAM_P pos);
104 void is_pt_free(ISPT ip);
107 * Read a key from a table.
109 int is_readkey(ISPT ip, void *buf);
111 int is_writekey(ISPT ip, const void *buf);
113 ISAM_P is_merge(ISAM is, ISAM_P pos, int num, const char *data);