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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}.
     40   constexpr Range() : Range(0) {}
     41 
     42   // Initializes the range with a start and 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.
     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}.
     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().
     63   constexpr bool IsValid() const { return *this != InvalidRange(); }
     64 
     65   // Getters and setters.
     66   constexpr uint32_t start() const { return start_; }
     67   void set_start(uint32_t start) { start_ = start; }
     68 
     69   constexpr uint32_t end() const { return end_; }
     70   void set_end(uint32_t end) { end_ = end; }
     71 
     72   // Returns the absolute value of the length.
     73   constexpr uint32_t length() const { return GetMax() - GetMin(); }
     74 
     75   constexpr bool is_reversed() const { return start() > end(); }
     76   constexpr bool is_empty() const { return start() == end(); }
     77 
     78   // Returns the minimum and maximum values.
     79   constexpr uint32_t GetMin() const {
     80     return start() < end() ? start() : end();
     81   }
     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   }
     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|.
     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|.
    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