SkTSearch.h revision 5956d1c224aadf1d2712b46b32d3fc69a19915bd 
1/*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef SkTSearch_DEFINED
18#define SkTSearch_DEFINED
19
20#include "SkTypes.h"
21
22template <typename T>
23int SkTSearch(const T* base, int count, const T& target, size_t elemSize)
24{
25    SkASSERT(count >= 0);
26    if (count <= 0)
27        return ~0;
28
29    SkASSERT(base != NULL); // base may be NULL if count is zero
30
31    int lo = 0;
32    int hi = count - 1;
33
34    while (lo < hi)
35    {
36        int mid = (hi + lo) >> 1;
37        const T* elem = (const T*)((const char*)base + mid * elemSize);
38
39        if (*elem < target)
40            lo = mid + 1;
41        else
42            hi = mid;
43    }
44
45    const T* elem = (const T*)((const char*)base + hi * elemSize);
46    if (*elem != target)
47    {
48        if (*elem < target)
49            hi += 1;
50        hi = ~hi;
51    }
52    return hi;
53}
54
55template <typename T>
56int SkTSearch(const T* base, int count, const T& target, size_t elemSize,
57              int (*compare)(const T&, const T&))
58{
59    SkASSERT(count >= 0);
60    if (count <= 0) {
61        return ~0;
62    }
63
64    SkASSERT(base != NULL); // base may be NULL if count is zero
65
66    int lo = 0;
67    int hi = count - 1;
68
69    while (lo < hi) {
70        int mid = (hi + lo) >> 1;
71        const T* elem = (const T*)((const char*)base + mid * elemSize);
72
73        if ((*compare)(*elem, target) < 0)
74            lo = mid + 1;
75        else
76            hi = mid;
77    }
78
79    const T* elem = (const T*)((const char*)base + hi * elemSize);
80    int pred = (*compare)(*elem, target);
81    if (pred != 0) {
82        if (pred < 0)
83            hi += 1;
84        hi = ~hi;
85    }
86    return hi;
87}
88
89template <typename T>
90int SkTSearch(const T** base, int count, const T* target, size_t elemSize,
91    int (*compare)(const T*, const T*))
92{
93    SkASSERT(count >= 0);
94    if (count <= 0)
95        return ~0;
96
97    SkASSERT(base != NULL); // base may be NULL if count is zero
98
99    int lo = 0;
100    int hi = count - 1;
101
102    while (lo < hi)
103    {
104        int mid = (hi + lo) >> 1;
105        const T* elem = *(const T**)((const char*)base + mid * elemSize);
106
107        if ((*compare)(elem, target) < 0)
108            lo = mid + 1;
109        else
110            hi = mid;
111    }
112
113    const T* elem = *(const T**)((const char*)base + hi * elemSize);
114    int pred = (*compare)(elem, target);
115    if (pred != 0)
116    {
117        if (pred < 0)
118            hi += 1;
119        hi = ~hi;
120    }
121    return hi;
122}
123
124int SkStrSearch(const char*const* base, int count, const char target[],
125                size_t target_len, size_t elemSize);
126int SkStrSearch(const char*const* base, int count, const char target[],
127                size_t elemSize);
128
129/** Like SkStrSearch, but treats target as if it were all lower-case. Assumes that
130    base points to a table of lower-case strings.
131*/
132int SkStrLCSearch(const char*const* base, int count, const char target[],
133                  size_t target_len, size_t elemSize);
134int SkStrLCSearch(const char*const* base, int count, const char target[],
135                  size_t elemSize);
136
137/** Helper class to convert a string to lower-case, but only modifying the ascii
138    characters. This makes the routine very fast and never changes the string
139    length, but it is not suitable for linguistic purposes. Normally this is
140    used for buiding and searching string tables.
141*/
142class SkAutoAsciiToLC {
143public:
144    SkAutoAsciiToLC(const char str[], size_t len = (size_t)-1);
145    ~SkAutoAsciiToLC();
146
147    const char* lc() const { return fLC; }
148    size_t      length() const { return fLength; }
149
150private:
151    char*   fLC;    // points to either the heap or fStorage
152    size_t  fLength;
153    enum {
154        STORAGE = 64
155    };
156    char    fStorage[STORAGE+1];
157};
158
159extern "C" {
160    typedef int (*SkQSortCompareProc)(const void*, const void*);
161    void SkQSort(void* base, size_t count, size_t elemSize, SkQSortCompareProc);
162}
163
164#endif
165
166