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comparison: docs/Writerside/topics/compare.h.md

docs/Writerside/topics/compare.h.md

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1 # Compare Functions 1 # Compare Functions
2 2
3 The `compare.h` header file contains a collection of compare functions for various primitive types. 3 The `compare.h` header file contains a collection of compare functions for various primitive types.
4 4
5 They come in two flavors: 5 They come in three flavors:
6 - prefixed with `cx_vcmp` they are taking the values directly as arguments 6 - prefixed with `cx_vcmp` they are taking the values directly as arguments
7 - prefixed with `cx_cmp` the signature is designed to be compatible with the `cx_compare_func` function pointer type. 7 - prefixed with `cx_cmp` the signature is designed to be compatible with the `cx_compare_func` function pointer type.
8 - prefixed with `cx_ccmp` the signature is designed to be compatible with the `cx_compare_func2` function pointer type.
8 9
9 ## Examples 10 ## Examples
10 11
11 In the following example we use `cx_cmp_int32` as compare function for a `CxList` of `int32_t` values. 12 In the following example we use `cx_cmp_int32` as compare function for a `CxList` of `int32_t` values.
12 13
13 ```C 14 ```C
14 CxList *list = cxArrayListCreate( 15 CxList *list = cxArrayListCreate(
15 cxDefaultAllocator, // use the default allocator 16 cxDefaultAllocator, // use the default allocator
16 cx_cmp_int32, // the compare function for the elements
17 sizeof(int32_t), // the size of one element 17 sizeof(int32_t), // the size of one element
18 256 // reseve space for 256 elements 18 256 // reseve space for 256 elements
19 ); 19 );
20 cxSetCompareFunc(list, cx_cmp_int32); // the compare function for the elements
20 ``` 21 ```
21 22
22 In the next example we simply want to compare two `double` values with rounding tolerance. 23 In the next example we simply want to compare two `double` values with rounding tolerance.
23 Note how the use of the `cx_vcmp` flavour makes it unnecessary to store the literal in a variable just to be able to take an address. 24 Note how the use of the `cx_vcmp` flavour makes it unnecessary to store the literal in a variable just to be able to take an address.
24 ```C 25 ```C
25 double x = ... 26 double x = ...
26 27
27 if (0 == cx_vcmp(x, 47.11)) { 28 if (0 == cx_vcmp(x, 47.11)) {
28 // do something when equal (except tolerance) 29 // do something when equal (except tolerance)
29 } 30 }
31 ```
32
33 If you only have a `cx_compare_func` at hand but need to call a function that expects a `cx_compare_func2` and a `context`,
34 you can use `cx_ccmp_wrap` and the `cx_compare_func_wrapper` struct to wrap your function.
35
36 ```C
37 void some_fun(int x, int y, cx_compare_func2 f, void *context);
38
39 cx_compare_func_wrapper wrapper = {my_cmp_fun};
40 some_fun(x, y, cx_ccmp_wrap, &wrapper);
30 ``` 41 ```
31 42
32 ## List of Functions 43 ## List of Functions
33 44
34 ```C 45 ```C
71 int cx_cmp_uint64(const void *a, const void *b); 82 int cx_cmp_uint64(const void *a, const void *b);
72 int cx_cmp_size(const void *a, const void *b); 83 int cx_cmp_size(const void *a, const void *b);
73 int cx_cmp_uintptr(const void *a, const void *b); 84 int cx_cmp_uintptr(const void *a, const void *b);
74 int cx_cmp_ulongint(const void *a, const void *b); 85 int cx_cmp_ulongint(const void *a, const void *b);
75 int cx_cmp_ulonglong(const void *a, const void *b); 86 int cx_cmp_ulonglong(const void *a, const void *b);
87
88 // Three-arguments Flavour
89 int cx_ccmp_memcmp(const void *a, const void *b, void *size);
90 int cx_ccmp_wrap(const void *a, const void *b, void *cmp_fun_wrapper);
76 ``` 91 ```
77 92
78 <seealso> 93 <seealso>
79 <category ref="apidoc"> 94 <category ref="apidoc">
80 <a href="https://ucx.sourceforge.io/api/compare_8h.html">compare.h</a> 95 <a href="https://ucx.sourceforge.io/api/compare_8h.html">compare.h</a>

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