2 * Copyright (C) 1994, Index Data I/S
4 * Sebastian Hammer, Adam Dickmeiss
7 * Revision 1.2 1994-09-27 20:03:52 quinn
8 * Seems relatively bug-free.
10 * Revision 1.1 1994/09/26 17:12:32 quinn
13 * Revision 1.1 1994/09/26 16:07:57 quinn
14 * Most of the functionality in place.
21 extern int is_mbuf_size[3];
23 typedef unsigned int ISAM_P;
26 * Memory buffer. Used to manage records (keys) in memory for
27 * reading and insertion/deletion.
29 typedef struct is_mbuf
33 #define IS_MBUF_TYPE_SMALL 0
34 #define IS_MBUF_TYPE_MEDIUM 1
35 #define IS_MBUF_TYPE_LARGE 2
40 char *data; /* dummy */
44 * Structure describing the virtual image of a disk block.
45 * (these blocks may grow beyond the blocksize during insertion).
47 typedef struct is_mblock
49 int num_records; /* number of records */
50 int diskpos; /* positive if this block is mapped */
51 int nextpos; /* pos of nxt blk. Only valid imm aft. rd. */
52 int bread; /* number of bytes read */
53 int state; /* state of block in rel. to disk block */
54 #define IS_MBSTATE_UNREAD 0 /* block hasn't been read */
55 #define IS_MBSTATE_PARTIAL 1 /* block has been partially read */
56 #define IS_MBSTATE_CLEAN 2 /* block is clean (unmodified) */
57 #define IS_MBSTATE_DIRTY 3 /* block has been modified */
59 is_mbuf *data; /* data contained in block */
61 struct is_mblock *next; /* next diskblock */
64 typedef struct isam_struct *ISAM;
66 * Descriptor for a specific table.
68 typedef struct is_mtable
70 int num_records; /* total number of records */
71 int pos_type; /* blocktype */
72 is_mblock *cur_mblock;
73 is_mblock *data; /* blocks contained in this table */
77 is_mblock *xmalloc_mblock();
78 is_mbuf *xmalloc_mbuf(int type);
79 void xfree_mblock(is_mblock *p);
80 void xfree_mblocks(is_mblock *l);
81 void xfree_mbuf(is_mbuf *p);
82 void xfree_mbufs(is_mbuf *l);
83 void xrelease_mblock(is_mblock *p);
84 void is_m_establish_tab(ISAM is, is_mtable *tab, ISAM_P pos);
85 void is_m_release_tab(is_mtable *tab);
86 void is_m_rewind(is_mtable *tab);
87 void is_m_replace_record(is_mtable *tab, const void *rec);
88 int is_m_write_record(is_mtable *tab, const void *rec);
89 void is_m_unread_record(is_mtable *tab);
90 int is_m_read_record(is_mtable *tab, void *buf);
91 int is_m_seek_record(is_mtable *tab, const void *rec);
92 void is_m_delete_record(is_mtable *tab);
93 int is_m_peek_record(is_mtable *tab, void *rec);
94 int is_m_read_full(is_mtable *tab, is_mblock *mblock);