comparison: ucx/iterator.c
ucx/iterator.c
- changeset 49
- 2f71f4ee247a
equal
deleted
inserted
replaced
| 48:ae61523bce20 | 49:2f71f4ee247a |
|---|---|
| 1 /* | |
| 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. | |
| 3 * | |
| 4 * Copyright 2024 Mike Becker, Olaf Wintermann All rights reserved. | |
| 5 * | |
| 6 * Redistribution and use in source and binary forms, with or without | |
| 7 * modification, are permitted provided that the following conditions are met: | |
| 8 * | |
| 9 * 1. Redistributions of source code must retain the above copyright | |
| 10 * notice, this list of conditions and the following disclaimer. | |
| 11 * | |
| 12 * 2. Redistributions in binary form must reproduce the above copyright | |
| 13 * notice, this list of conditions and the following disclaimer in the | |
| 14 * documentation and/or other materials provided with the distribution. | |
| 15 * | |
| 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE | |
| 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 26 * POSSIBILITY OF SUCH DAMAGE. | |
| 27 */ | |
| 28 | |
| 29 #include "cx/iterator.h" | |
| 30 | |
| 31 #include <string.h> | |
| 32 | |
| 33 static bool cx_iter_valid(const void *it) { | |
| 34 const struct cx_iterator_s *iter = it; | |
| 35 return iter->index < iter->elem_count; | |
| 36 } | |
| 37 | |
| 38 static void *cx_iter_current(const void *it) { | |
| 39 const struct cx_iterator_s *iter = it; | |
| 40 return iter->elem_handle; | |
| 41 } | |
| 42 | |
| 43 static void cx_iter_next_fast(void *it) { | |
| 44 struct cx_iterator_s *iter = it; | |
| 45 if (iter->base.remove) { | |
| 46 iter->base.remove = false; | |
| 47 iter->elem_count--; | |
| 48 // only move the last element when we are not currently aiming | |
| 49 // at the last element already | |
| 50 if (iter->index < iter->elem_count) { | |
| 51 void *last = ((char *) iter->src_handle.m) | |
| 52 + iter->elem_count * iter->elem_size; | |
| 53 memcpy(iter->elem_handle, last, iter->elem_size); | |
| 54 } | |
| 55 } else { | |
| 56 iter->index++; | |
| 57 iter->elem_handle = ((char *) iter->elem_handle) + iter->elem_size; | |
| 58 } | |
| 59 } | |
| 60 | |
| 61 static void cx_iter_next_slow(void *it) { | |
| 62 struct cx_iterator_s *iter = it; | |
| 63 if (iter->base.remove) { | |
| 64 iter->base.remove = false; | |
| 65 iter->elem_count--; | |
| 66 | |
| 67 // number of elements to move | |
| 68 size_t remaining = iter->elem_count - iter->index; | |
| 69 if (remaining > 0) { | |
| 70 memmove( | |
| 71 iter->elem_handle, | |
| 72 ((char *) iter->elem_handle) + iter->elem_size, | |
| 73 remaining * iter->elem_size | |
| 74 ); | |
| 75 } | |
| 76 } else { | |
| 77 iter->index++; | |
| 78 iter->elem_handle = ((char *) iter->elem_handle) + iter->elem_size; | |
| 79 } | |
| 80 } | |
| 81 | |
| 82 CxIterator cxMutIterator( | |
| 83 void *array, | |
| 84 size_t elem_size, | |
| 85 size_t elem_count, | |
| 86 bool remove_keeps_order | |
| 87 ) { | |
| 88 CxIterator iter; | |
| 89 | |
| 90 iter.index = 0; | |
| 91 iter.src_handle.m = array; | |
| 92 iter.elem_handle = array; | |
| 93 iter.elem_size = elem_size; | |
| 94 iter.elem_count = array == NULL ? 0 : elem_count; | |
| 95 iter.base.valid = cx_iter_valid; | |
| 96 iter.base.current = cx_iter_current; | |
| 97 iter.base.next = remove_keeps_order ? cx_iter_next_slow : cx_iter_next_fast; | |
| 98 iter.base.remove = false; | |
| 99 iter.base.mutating = true; | |
| 100 | |
| 101 return iter; | |
| 102 } | |
| 103 | |
| 104 CxIterator cxIterator( | |
| 105 const void *array, | |
| 106 size_t elem_size, | |
| 107 size_t elem_count | |
| 108 ) { | |
| 109 CxIterator iter = cxMutIterator((void*)array, elem_size, elem_count, false); | |
| 110 iter.base.mutating = false; | |
| 111 return iter; | |
| 112 } |
