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13 | .. |
14 | .TH dspool 3mLib "20 June 1999" mLib |
15 | .SH NAME |
16 | dspool \- pools of preallocated dynamic strings |
17 | .SH SYNOPSIS |
18 | .nf |
19 | .B "#include <mLib/dspool.h> |
20 | |
21 | .BI "void dspool_create(dspool *" p ", size_t " isz ); |
22 | .BI "void dspool_destroy(dspool *" p ); |
23 | .BI "dstr *dspool_get(dspool *" p ); |
24 | .BI "void dspool_put(dspool *" p ", dstr *" d ); |
25 | |
26 | .BI "dstr *DSGET(dspool *" p ", d ); |
27 | .BI "void DSPUT(dspool *" p ", dstr *" d ); |
28 | .fi |
29 | .SH DESCRIPTION |
30 | A dynamic string pool maintains a collection of `spare' dynamic |
31 | strings. Some pieces of code require high turnover of strings, and |
32 | allocating and freeing them entails a large amount of overhead. A |
33 | dynamic string pool keeps a list of dynamic strings which have been |
34 | allocated but are not currently in use. |
35 | .PP |
36 | A pool is created by the function |
37 | .BR dspool_create . |
38 | It is passed the address of a pool structure |
39 | .I p |
40 | and the initial size |
41 | .I izs |
42 | to allocate for new dynamic strings obtained from the pool. A newly |
43 | created pool contains no strings. Once a pool is no longer required, |
44 | the function |
45 | .B dspool_destroy |
46 | will release all the strings in the pool, such that the pool can safely |
47 | be thrown away. |
48 | .PP |
49 | A string is obtained from a pool by calling |
50 | .BR dspool_get . |
51 | If the pool is empty, a new string is allocated; otherwise a string is |
52 | chosen from those currently in the pool. |
53 | .PP |
54 | A string is returned to the pool by the |
55 | .B dspool_put |
56 | function. It is passed the address of a pool and the address of a |
57 | string to return. The string must have been allocated from |
58 | .I some |
59 | dynamic string pool, although it's not actually necessary to return it |
60 | to the pool from which it was allocated. |
61 | .PP |
62 | The macro call |
63 | .VS |
64 | DSGET(p, d); |
65 | .VE |
66 | is equivalent to the assignment |
67 | .VS |
68 | d = dspool_get(p); |
69 | .VE |
70 | (except that it's probably quicker). The macro |
71 | .B DSPUT |
72 | is entirely equivalent to the function |
73 | .B dspool_put |
74 | except for improved performance. |
75 | .SH CAVEATS |
76 | The string pool allocator requires the suballocator (see |
77 | .BR sub (3mLib) |
78 | for details). You must ensure that |
79 | .B sub_init |
80 | is called before any strings are allocated from a string pool. |
81 | .SH SEE ALSO |
82 | .BR dstr (3mLib), |
83 | .BR sub (3mLib). |
84 | .SH AUTHOR |
85 | Mark Wooding, <mdw@nsict.org> |