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