comparison: docs/Writerside/topics/hash_map.h.md
docs/Writerside/topics/hash_map.h.md
- changeset 1424
- 563033aa998c
- parent 1318
- 12fa1d37fe48
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| 1423:9a72258446cd | 1424:563033aa998c |
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| 1 # Hash Map | 1 # Hash Map |
| 2 | 2 |
| 3 UCX provides a basic hash map implementation with a configurable amount of buckets. | 3 UCX provides a basic hash map implementation with a configurable number of buckets. |
| 4 If you do not specify the number of buckets, a default of 16 buckets will be used. | 4 If you do not specify the number of buckets, a default of 16 buckets will be used. |
| 5 | 5 |
| 6 You can always rehash the map with `cxMapRehash()` to change the number of buckets to something more efficient, | 6 You can always rehash the map with `cxMapRehash()` to change the number of buckets to something more efficient, |
| 7 but you need to be careful, because when you use this function you are effectively locking into using this | 7 but you need to be careful, because when you use this function you are effectively locking into using this |
| 8 specific hash map implementation, and you would need to remove all calls to this function when you want to | 8 specific hash map implementation, and you would need to remove all calls to this function when you want to |
| 26 The map will store items of size `itemsize`. | 26 The map will store items of size `itemsize`. |
| 27 You can use the `CX_STORE_POINTERS` macro for `itemsize` to indicate that the map shall store | 27 You can use the `CX_STORE_POINTERS` macro for `itemsize` to indicate that the map shall store |
| 28 pointers instead of actual items. | 28 pointers instead of actual items. |
| 29 | 29 |
| 30 If you pass zero for the number of `buckets`, or use `cxHashMapSimple()`, | 30 If you pass zero for the number of `buckets`, or use `cxHashMapSimple()`, |
| 31 the map is initialized with a default of 16 buckets, otherwise the specified number of buckets is allocated. | 31 the map is initialized with a default of 16 buckets; otherwise the specified number of buckets is allocated. |
| 32 | 32 |
| 33 The function `cxMapRehash()` allocates a new array of buckets and re-distributes all elements, | 33 The function `cxMapRehash()` allocates a new array of buckets and re-distributes all elements, |
| 34 if the number of elements exceeds ¾ of the number of buckets. | 34 if the number of elements exceeds ¾ of the number of buckets. |
| 35 Otherwise, no action is performed and this function simply returns 0. | 35 Otherwise, no action is performed, and this function simply returns 0. |
| 36 After rehashing, the number of buckets is at least 2½ times the number of elements. | 36 After rehashing, the number of buckets is at least 2½ times the number of elements. |
| 37 | 37 |
| 38 > Advice if you want to create your own hash map structures: | 38 > Advice if you want to create your own hash map structures: |
| 39 > Calling `cxMapRehash()` on a map is only defined, when the map is based on the | 39 > Calling `cxMapRehash()` on a map is only defined, when the map is based on the |
| 40 > `struct cx_hash_map_s` structure. | 40 > `struct cx_hash_map_s` structure. |
