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1/*
2 * This file Copyright (C) Mnemosyne LLC
3 *
4 * This file is licensed by the GPL version 2. Works owned by the
5 * Transmission project are granted a special exemption to clause 2(b)
6 * so that the bulk of its code can remain under the MIT license.
7 * This exemption does not extend to derived works not owned by
8 * the Transmission project.
9 *
10 * $Id: ptrarray.c 12606 2011-07-31 14:04:43Z jordan $
11 */
12
13#include <assert.h>
14#include <stdlib.h> /* tr_renew() -> realloc() */
15#include <string.h> /* memmove */
16
17#include "ptrarray.h"
18#include "utils.h"
19
20#define FLOOR 32
21
22const tr_ptrArray TR_PTR_ARRAY_INIT = { NULL, 0, 0 };
23
24void
25tr_ptrArrayDestruct( tr_ptrArray * p, PtrArrayForeachFunc func )
26{
27    assert( p );
28    assert( p->items || !p->n_items );
29
30    if( func )
31        tr_ptrArrayForeach( p, func );
32
33    tr_free( p->items );
34
35    memset( p, ~0, sizeof( tr_ptrArray ) );
36}
37
38void
39tr_ptrArrayForeach( tr_ptrArray *       t,
40                    PtrArrayForeachFunc func )
41{
42    int i;
43
44    assert( t );
45    assert( t->items || !t->n_items );
46    assert( func );
47
48    for( i = 0; i < t->n_items; ++i )
49        func( t->items[i] );
50}
51
52void**
53tr_ptrArrayPeek( tr_ptrArray * t,
54                 int *         size )
55{
56    *size = t->n_items;
57    return t->items;
58}
59
60int
61tr_ptrArrayInsert( tr_ptrArray * t,
62                   void        * ptr,
63                   int           pos )
64{
65    if( t->n_items >= t->n_alloc )
66    {
67        t->n_alloc = MAX( FLOOR, t->n_alloc * 2 );
68        t->items = tr_renew( void*, t->items, t->n_alloc );
69    }
70
71    if( pos < 0 || pos > t->n_items )
72        pos = t->n_items;
73    else
74        memmove( t->items + pos + 1,
75                 t->items + pos,
76                 sizeof( void* ) * ( t->n_items - pos ) );
77
78    t->items[pos] = ptr;
79    t->n_items++;
80    return pos;
81}
82
83void*
84tr_ptrArrayPop( tr_ptrArray* t )
85{
86    void * ret = NULL;
87
88    if( t->n_items )
89        ret = t->items[--t->n_items];
90
91    return ret;
92}
93
94void
95tr_ptrArrayErase( tr_ptrArray * t,
96                  int           begin,
97                  int           end )
98{
99    assert( begin >= 0 );
100    if( end < 0 ) end = t->n_items;
101    assert( begin < end );
102    assert( end <= t->n_items );
103
104    memmove( t->items + begin,
105             t->items + end,
106             sizeof( void* ) * ( t->n_items - end ) );
107
108    t->n_items -= ( end - begin );
109}
110
111/**
112***
113**/
114
115int
116tr_ptrArrayLowerBound( const tr_ptrArray  * t,
117                       const void         * ptr,
118                       int                  compare( const void *, const void * ),
119                       bool               * exact_match )
120{
121    int pos = -1;
122    bool match = false;
123
124    if( t->n_items == 0 )
125    {
126        pos = 0;
127    }
128    else
129    {
130        int first = 0;
131        int last = t->n_items - 1;
132
133        for( ;; )
134        {
135            const int half = (last - first) / 2;
136            const int c = compare( t->items[first + half], ptr );
137
138            if( c < 0 ) {
139                const int new_first = first + half + 1;
140                if( new_first > last ) {
141                    pos = new_first;
142                    break;
143                }
144                first = new_first;
145            }
146            else if( c > 0 ) {
147                const int new_last = first + half - 1;
148                if( new_last < first ) {
149                    pos = first;
150                    break;
151                }
152                last = new_last;
153            }
154            else {
155                match = true;
156                pos = first + half;
157                break;
158            }
159        }
160    }
161
162    if( exact_match )
163        *exact_match = match;
164    return pos;
165}
166
167static void
168assertSortedAndUnique( const tr_ptrArray * t UNUSED,
169                       int compare(const void*, const void*) UNUSED )
170{
171#ifndef NDEBUG
172    int i;
173
174    for( i = 0; i < t->n_items - 2; ++i )
175        assert( compare( t->items[i], t->items[i + 1] ) < 0 );
176#endif
177}
178
179int
180tr_ptrArrayInsertSorted( tr_ptrArray * t,
181                         void *        ptr,
182                         int           compare(const void*, const void*) )
183{
184    int pos;
185    int ret;
186
187    assertSortedAndUnique( t, compare );
188
189    pos = tr_ptrArrayLowerBound( t, ptr, compare, NULL );
190    ret = tr_ptrArrayInsert( t, ptr, pos );
191
192    assertSortedAndUnique( t, compare );
193    return ret;
194}
195
196void*
197tr_ptrArrayFindSorted( tr_ptrArray * t,
198                       const void *  ptr,
199                       int           compare(const void*, const void*) )
200{
201    bool match = false;
202    const int pos = tr_ptrArrayLowerBound( t, ptr, compare, &match );
203    return match ? t->items[pos] : NULL;
204}
205
206void*
207tr_ptrArrayRemoveSorted( tr_ptrArray * t,
208                         const void  * ptr,
209                         int           compare(const void*, const void*) )
210{
211    bool match;
212    void * ret = NULL;
213    const int pos = tr_ptrArrayLowerBound( t, ptr, compare, &match );
214    assertSortedAndUnique( t, compare );
215
216    if( match )
217    {
218        ret = t->items[pos];
219        assert( compare( ret, ptr ) == 0 );
220        tr_ptrArrayErase( t, pos, pos + 1 );
221    }
222    assertSortedAndUnique( t, compare );
223    assert( ( ret == NULL ) || ( compare( ret, ptr ) == 0 ) );
224    return ret;
225}
226