device/hid/hid_report_descriptor_item.h

   1 // Copyright 2014 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 DEVICE_HID_HID_REPORT_DESCRIPTOR_ITEM_H_
   6 #define DEVICE_HID_HID_REPORT_DESCRIPTOR_ITEM_H_
   7
   8 #include "base/basictypes.h"
   9
  10 namespace device {
  11
  12 // An element of a HID report descriptor.
  13 class HidReportDescriptorItem {
  14  private:
  15   friend class HidReportDescriptor;
  16
  17   enum Type {
  18     kTypeMain = 0,
  19     kTypeGlobal = 1,
  20     kTypeLocal = 2,
  21     kTypeReserved = 3
  22   };
  23
  24   enum MainTag {
  25     kMainTagDefault = 0x00,       // 0000
  26     kMainTagInput = 0x08,         // 1000
  27     kMainTagOutput = 0x09,        // 1001
  28     kMainTagFeature = 0x0B,       // 1011
  29     kMainTagCollection = 0x0A,    // 1010
  30     kMainTagEndCollection = 0x0C  // 1100
  31   };
  32
  33   enum GlobalTag {
  34     kGlobalTagUsagePage = 0x00,        // 0000
  35     kGlobalTagLogicalMinimum = 0x01,   // 0001
  36     kGlobalTagLogicalMaximum = 0x02,   // 0010
  37     kGlobalTagPhysicalMinimum = 0x03,  // 0011
  38     kGlobalTagPhysicalMaximum = 0x04,  // 0100
  39     kGlobalTagUnitExponent = 0x05,     // 0101
  40     kGlobalTagUnit = 0x06,             // 0110
  41     kGlobalTagReportSize = 0x07,       // 0111
  42     kGlobalTagReportId = 0x08,         // 1000
  43     kGlobalTagReportCount = 0x09,      // 1001
  44     kGlobalTagPush = 0x0A,             // 1010
  45     kGlobalTagPop = 0x0B               // 1011
  46   };
  47
  48   enum LocalTag {
  49     kLocalTagUsage = 0x00,              // 0000
  50     kLocalTagUsageMinimum = 0x01,       // 0001
  51     kLocalTagUsageMaximum = 0x02,       // 0010
  52     kLocalTagDesignatorIndex = 0x03,    // 0011
  53     kLocalTagDesignatorMinimum = 0x04,  // 0100
  54     kLocalTagDesignatorMaximum = 0x05,  // 0101
  55     kLocalTagStringIndex = 0x07,        // 0111
  56     kLocalTagStringMinimum = 0x08,      // 1000
  57     kLocalTagStringMaximum = 0x09,      // 1001
  58     kLocalTagDelimiter = 0x0A           // 1010
  59   };
  60
  61   enum ReservedTag {
  62     kReservedTagLong = 0xF  // 1111
  63   };
  64
  65  public:
  66   enum Tag {
  67     kTagDefault = kMainTagDefault << 2 | kTypeMain,
  68     kTagInput = kMainTagInput << 2 | kTypeMain,
  69     kTagOutput = kMainTagOutput << 2 | kTypeMain,
  70     kTagFeature = kMainTagFeature << 2 | kTypeMain,
  71     kTagCollection = kMainTagCollection << 2 | kTypeMain,
  72     kTagEndCollection = kMainTagEndCollection << 2 | kTypeMain,
  73     kTagUsagePage = kGlobalTagUsagePage << 2 | kTypeGlobal,
  74     kTagLogicalMinimum = kGlobalTagLogicalMinimum << 2 | kTypeGlobal,
  75     kTagLogicalMaximum = kGlobalTagLogicalMaximum << 2 | kTypeGlobal,
  76     kTagPhysicalMinimum = kGlobalTagPhysicalMinimum << 2 | kTypeGlobal,
  77     kTagPhysicalMaximum = kGlobalTagPhysicalMaximum << 2 | kTypeGlobal,
  78     kTagUnitExponent = kGlobalTagUnitExponent << 2 | kTypeGlobal,
  79     kTagUnit = kGlobalTagUnit << 2 | kTypeGlobal,
  80     kTagReportSize = kGlobalTagReportSize << 2 | kTypeGlobal,
  81     kTagReportId = kGlobalTagReportId << 2 | kTypeGlobal,
  82     kTagReportCount = kGlobalTagReportCount << 2 | kTypeGlobal,
  83     kTagPush = kGlobalTagPush << 2 | kTypeGlobal,
  84     kTagPop = kGlobalTagPop << 2 | kTypeGlobal,
  85     kTagUsage = kLocalTagUsage << 2 | kTypeLocal,
  86     kTagUsageMinimum = kLocalTagUsageMinimum << 2 | kTypeLocal,
  87     kTagUsageMaximum = kLocalTagUsageMaximum << 2 | kTypeLocal,
  88     kTagDesignatorIndex = kLocalTagDesignatorIndex << 2 | kTypeLocal,
  89     kTagDesignatorMinimum = kLocalTagDesignatorMinimum << 2 | kTypeLocal,
  90     kTagDesignatorMaximum = kLocalTagDesignatorMaximum << 2 | kTypeLocal,
  91     kTagStringIndex = kLocalTagStringIndex << 2 | kTypeLocal,
  92     kTagStringMinimum = kLocalTagStringMinimum << 2 | kTypeLocal,
  93     kTagStringMaximum = kLocalTagStringMaximum << 2 | kTypeLocal,
  94     kTagDelimiter = kLocalTagDelimiter << 2 | kTypeLocal,
  95     kTagLong = kReservedTagLong << 2 | kTypeReserved
  96   };
  97
  98   // HID Input/Output/Feature report information.
  99   // Can be retrieved from GetShortData()
 100   // when item.tag() == HidReportDescriptorItem::kTagInput
 101   // or HidReportDescriptorItem::kTagOutput
 102   // or HidReportDescriptorItem::kTagFeature
 103   struct ReportInfo {
 104     uint8_t data_or_constant : 1;
 105     uint8_t array_or_variable : 1;
 106     uint8_t absolute_or_relative : 1;
 107     uint8_t wrap : 1;
 108     uint8_t linear : 1;
 109     uint8_t preferred : 1;
 110     uint8_t null : 1;
 111     uint8_t reserved_1 : 1;
 112     uint8_t bit_field_or_buffer : 1;
 113     uint8_t reserved_2 : 1;
 114   };
 115
 116   // HID collection type.
 117   // Can be retrieved from GetShortData()
 118   // when item.tag() == HidReportDescriptorItem::kTagCollection
 119   enum CollectionType {
 120     kCollectionTypePhysical,
 121     kCollectionTypeApplication,
 122     kCollectionTypeLogical,
 123     kCollectionTypeReport,
 124     kCollectionTypeNamedArray,
 125     kCollectionTypeUsageSwitch,
 126     kCollectionTypeUsageModifier,
 127     kCollectionTypeReserved,
 128     kCollectionTypeVendor
 129   };
 130
 131  private:
 132   HidReportDescriptorItem(const uint8_t* bytes,
 133                           HidReportDescriptorItem* previous);
 134
 135  public:
 136   ~HidReportDescriptorItem() {}
 137
 138   // Previous element in report descriptor.
 139   // Owned by descriptor instance.
 140   HidReportDescriptorItem* previous() const {
 141     return previous_;
 142   };
 143   // Next element in report descriptor.
 144   // Owned by descriptor instance.
 145   HidReportDescriptorItem* next() const {
 146     return next_;
 147   };
 148   // Parent element in report descriptor.
 149   // Owned by descriptor instance.
 150   // Can be NULL.
 151   HidReportDescriptorItem* parent() const {
 152     return parent_;
 153   };
 154   // Level in Parent-Children relationship tree.
 155   // 0 for top-level items (parent()==NULL).
 156   // 1 if parent() is top-level.
 157   // 2 if parent() has a top-level parent. Etc.
 158   size_t GetDepth() const;
 159   Tag tag() const { return tag_; }
 160   // Returns true for a long item, false otherwise.
 161   bool IsLong() const;
 162   // Raw data of a short item.
 163   // Not valid for a long item.
 164   uint32_t GetShortData() const;
 165
 166   static CollectionType GetCollectionTypeFromValue(uint32_t value);
 167
 168  private:
 169   size_t GetHeaderSize() const;
 170   size_t payload_size() const { return payload_size_; }
 171   size_t GetSize() const;
 172
 173   HidReportDescriptorItem* previous_;
 174   HidReportDescriptorItem* next_;
 175   HidReportDescriptorItem* parent_;
 176   Tag tag_;
 177   uint32_t shortData_;
 178   size_t payload_size_;
 179 };
 180
 181 }  // namespace device
 182
 183 #endif  // DEVICE_HID_HID_REPORT_DESCRIPTOR_ITEM_H_