aboutsummaryrefslogtreecommitdiff
path: root/common/algorithm.h
blob: 01042536f6d88e75052c87bf29bbe86505871aad (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 */

#ifndef COMMON_ALGORITHM_H
#define COMMON_ALGORITHM_H

#include "common/scummsys.h"

namespace Common {

/**
 * Copies data from the range [first, last) to [dst, dst + (last - first)).
 * It requires the range [dst, dst + (last - first)) to be valid.
 * It also requires dst not to be in the range [first, last).
 */
template<class In, class Out>
Out copy(In first, In last, Out dst) {
	while (first != last)
		*dst++ = *first++;
	return dst;
}

/**
 * Copies data from the range [first, last) to [dst - (last - first), dst).
 * It requires the range [dst - (last - first), dst) to be valid.
 * It also requires dst not to be in the range [first, last).
 *
 * Unlike copy copy_backward copies the data from the end to the beginning.
 */
template<class In, class Out>
Out copy_backward(In first, In last, Out dst) {
	while (first != last)
		*--dst = *--last;
	return dst;
}

/**
 * Copies data from the range [first, last) to [dst, dst + (last - first)).
 * It requires the range [dst, dst + (last - first)) to be valid.
 * It also requires dst not to be in the range [first, last).
 *
 * Unlike copy or copy_backward it does not copy all data. It only copies
 * a data element when operator() of the op parameter returns true for the
 * passed data element.
 */
template<class In, class Out, class Op>
Out copy_if(In first, In last, Out dst, Op op) {
	while (first != last) {
		if (op(*first))
			*dst++ = *first;
		++first;
	}
	return dst;
}

// Our 'specialized' 'set_to' template for char, signed char and unsigned char arrays.
// Since C++ doesn't support partial specialized template functions (currently) we
// are going this way...
// With this we assure the usage of memset for those, which should be
// faster than a simple loop like for the generic 'set_to'.
template<class Value>
signed char *set_to(signed char *first, signed char *last, Value val) {
	memset(first, (val & 0xFF), last - first);
	return last;
}

template<class Value>
unsigned char *set_to(unsigned char *first, unsigned char *last, Value val) {
	memset(first, (val & 0xFF), last - first);
	return last;
}

template<class Value>
char *set_to(char *first, char *last, Value val) {
	memset(first, (val & 0xFF), last - first);
	return last;
}

/**
 * Sets all elements in the range [first, last) to val.
 */
template<class In, class Value>
In set_to(In first, In last, Value val) {
	while (first != last)
		*first++ = val;
	return first;
}

/**
 * Finds the first data value in the range [first, last) matching v.
 * For data comperance it uses operator == of the data elements.
 */
template<class In, class T>
In find(In first, In last, const T &v) {
	while (first != last) {
		if (*first == v)
			return first;
		++first;
	}
	return last;
}

/**
 * Finds the first data value in the range [first, last) for which
 * the specified predicate p returns true.
 */
template<class In, class Pred>
In find_if(In first, In last, Pred p) {
	while (first != last) {
		if (p(*first))
			return first;
		++first;
	}
	return last;
}

/**
 * Applies the function f on all elements of the range [first, last).
 * The processing order is from beginning to end.
 */
template<class In, class Op>
Op for_each(In first, In last, Op f) {
	while (first != last) f(*first++);
	return f;
}

/**
 * Simple sort function, modeled after std::sort.
 * Use it like this: sort(container.begin(), container.end()).
 * Also works on plain old i.e. int arrays etc. For comperance
 * operator < is used.
 */
template<class T>
void sort(T first, T last) {
	if (first == last)
		return;

	// Simple selection sort
	T i(first);
	for (; i != last; ++i) {
		T minElem(i);
		T j(i);
		++j;
		for (; j != last; ++j)
			if (*j < *minElem)
				minElem = j;
		if (minElem != i)
			SWAP(*minElem, *i);
	}
}

/**
 * Simple sort function, modeled after std::sort.
 * It compares data with the given comparator object comp.
 *
 * Note: Using this with: Common::Less from common/func.h
 * will give the same results as the plain sort function.
 */
template<class T, class StrictWeakOrdering>
void sort(T first, T last, StrictWeakOrdering comp) {
	if (first == last)
		return;

	// Simple selection sort
	T i(first);
	for (; i != last; ++i) {
		T minElem(i);
		T j(i);
		++j;
		for (; j != last; ++j)
			if (comp(*j, *minElem))
				minElem = j;
		if (minElem != i)
			SWAP(*minElem, *i);
	}
}

} // End of namespace Common
#endif