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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef UI_GFX_RANGE_RANGE_H_
6 #define UI_GFX_RANGE_RANGE_H_
7 
8 #include <stddef.h>
9 #include <stdint.h>
10 
11 #include <limits>
12 #include <ostream>
13 #include <string>
14 
15 #include "build/build_config.h"
16 #include "ui/gfx/range/gfx_range_export.h"
17 
18 #if defined(OS_MACOSX)
19 #if __OBJC__
20 #import <Foundation/Foundation.h>
21 #else
22 typedef struct _NSRange NSRange;
23 #endif
24 #endif  // defined(OS_MACOSX)
25 
26 #if defined(OS_WIN)
27 typedef struct _charrange CHARRANGE;
28 #endif
29 
30 namespace gfx {
31 
32 // A Range contains two integer values that represent a numeric range, like the
33 // range of characters in a text selection. A range is made of a start and end
34 // position; when they are the same, the Range is akin to a caret. Note that
35 // |start_| can be greater than |end_| to respect the directionality of the
36 // range.
37 class GFX_RANGE_EXPORT Range {
38  public:
39   // Creates an empty range {0,0}.
Range()40   constexpr Range() : Range(0) {}
41 
42   // Initializes the range with a start and end.
Range(uint32_t start,uint32_t end)43   constexpr Range(uint32_t start, uint32_t end) : start_(start), end_(end) {}
44 
45   // Initializes the range with the same start and end positions.
Range(uint32_t position)46   constexpr explicit Range(uint32_t position) : Range(position, position) {}
47 
48   // Platform constructors.
49 #if defined(OS_MACOSX)
50   explicit Range(const NSRange& range);
51 #elif defined(OS_WIN)
52   // The |total_length| paramater should be used if the CHARRANGE is set to
53   // {0,-1} to indicate the whole range.
54   Range(const CHARRANGE& range, long total_length = -1);
55 #endif
56 
57   // Returns a range that is invalid, which is {UINT32_MAX,UINT32_MAX}.
InvalidRange()58   static constexpr Range InvalidRange() {
59     return Range(std::numeric_limits<uint32_t>::max());
60   }
61 
62   // Checks if the range is valid through comparison to InvalidRange().
IsValid()63   constexpr bool IsValid() const { return *this != InvalidRange(); }
64 
65   // Getters and setters.
start()66   constexpr uint32_t start() const { return start_; }
set_start(uint32_t start)67   void set_start(uint32_t start) { start_ = start; }
68 
end()69   constexpr uint32_t end() const { return end_; }
set_end(uint32_t end)70   void set_end(uint32_t end) { end_ = end; }
71 
72   // Returns the absolute value of the length.
length()73   constexpr uint32_t length() const { return GetMax() - GetMin(); }
74 
is_reversed()75   constexpr bool is_reversed() const { return start() > end(); }
is_empty()76   constexpr bool is_empty() const { return start() == end(); }
77 
78   // Returns the minimum and maximum values.
GetMin()79   constexpr uint32_t GetMin() const {
80     return start() < end() ? start() : end();
81   }
GetMax()82   constexpr uint32_t GetMax() const {
83     return start() > end() ? start() : end();
84   }
85 
86   constexpr bool operator==(const Range& other) const {
87     return start() == other.start() && end() == other.end();
88   }
89   constexpr bool operator!=(const Range& other) const {
90     return !(*this == other);
91   }
EqualsIgnoringDirection(const Range & other)92   constexpr bool EqualsIgnoringDirection(const Range& other) const {
93     return GetMin() == other.GetMin() && GetMax() == other.GetMax();
94   }
95 
96   // Returns true if this range intersects the specified |range|.
Intersects(const Range & range)97   constexpr bool Intersects(const Range& range) const {
98     return IsValid() && range.IsValid() &&
99            !(range.GetMax() < GetMin() || range.GetMin() >= GetMax());
100   }
101 
102   // Returns true if this range contains the specified |range|.
Contains(const Range & range)103   constexpr bool Contains(const Range& range) const {
104     return IsValid() && range.IsValid() && GetMin() <= range.GetMin() &&
105            range.GetMax() <= GetMax();
106   }
107 
108   // Computes the intersection of this range with the given |range|.
109   // If they don't intersect, it returns an InvalidRange().
110   // The returned range is always empty or forward (never reversed).
111   Range Intersect(const Range& range) const;
112 
113 #if defined(OS_MACOSX)
114   Range& operator=(const NSRange& range);
115 
116   // NSRange does not store the directionality of a range, so if this
117   // is_reversed(), the range will get flipped when converted to an NSRange.
118   NSRange ToNSRange() const;
119 #elif defined(OS_WIN)
120   CHARRANGE ToCHARRANGE() const;
121 #endif
122   // GTK+ has no concept of a range.
123 
124   std::string ToString() const;
125 
126  private:
127   // Note: we use uint32_t instead of size_t because this struct is sent over
128   // IPC which could span 32 & 64 bit processes. This is fine since text spans
129   // shouldn't exceed UINT32_MAX even on 64 bit builds.
130   uint32_t start_;
131   uint32_t end_;
132 };
133 
134 GFX_RANGE_EXPORT std::ostream& operator<<(std::ostream& os, const Range& range);
135 
136 }  // namespace gfx
137 
138 #endif  // UI_GFX_RANGE_RANGE_H_
139