HID: Support top-level collection usages in device info.

device/hid/hid_report_descriptor_item.h

Index: device/hid/hid_report_descriptor_item.h
diff --git a/device/hid/hid_report_descriptor_item.h b/device/hid/hid_report_descriptor_item.h
new file mode 100644
index 0000000000000000000000000000000000000000..d3392330709e6d3928b2a2cc3b4f54b2fa61acb0
--- /dev/null
+++ b/device/hid/hid_report_descriptor_item.h
@@ -0,0 +1,183 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DEVICE_HID_HID_REPORT_DESCRIPTOR_ITEM_H_
+#define DEVICE_HID_HID_REPORT_DESCRIPTOR_ITEM_H_
+
+#include "base/basictypes.h"
+
+namespace device {
+
+// An element of a HID report descriptor.
+class HidReportDescriptorItem {
+ private:
+  friend class HidReportDescriptor;
+
+  enum Type {
+    kTypeMain = 0,
+    kTypeGlobal = 1,
+    kTypeLocal = 2,
+    kTypeReserved = 3
+  };
+
+  enum MainTag {
+    kMainTagDefault = 0x00,       // 0000
+    kMainTagInput = 0x08,         // 1000
+    kMainTagOutput = 0x09,        // 1001
+    kMainTagFeature = 0x0B,       // 1011
+    kMainTagCollection = 0x0A,    // 1010
+    kMainTagEndCollection = 0x0C  // 1100
+  };
+
+  enum GlobalTag {
+    kGlobalTagUsagePage = 0x00,        // 0000
+    kGlobalTagLogicalMinimum = 0x01,   // 0001
+    kGlobalTagLogicalMaximum = 0x02,   // 0010
+    kGlobalTagPhysicalMinimum = 0x03,  // 0011
+    kGlobalTagPhysicalMaximum = 0x04,  // 0100
+    kGlobalTagUnitExponent = 0x05,     // 0101
+    kGlobalTagUnit = 0x06,             // 0110
+    kGlobalTagReportSize = 0x07,       // 0111
+    kGlobalTagReportId = 0x08,         // 1000
+    kGlobalTagReportCount = 0x09,      // 1001
+    kGlobalTagPush = 0x0A,             // 1010
+    kGlobalTagPop = 0x0B               // 1011
+  };
+
+  enum LocalTag {
+    kLocalTagUsage = 0x00,              // 0000
+    kLocalTagUsageMinimum = 0x01,       // 0001
+    kLocalTagUsageMaximum = 0x02,       // 0010
+    kLocalTagDesignatorIndex = 0x03,    // 0011
+    kLocalTagDesignatorMinimum = 0x04,  // 0100
+    kLocalTagDesignatorMaximum = 0x05,  // 0101
+    kLocalTagStringIndex = 0x07,        // 0111
+    kLocalTagStringMinimum = 0x08,      // 1000
+    kLocalTagStringMaximum = 0x09,      // 1001
+    kLocalTagDelimiter = 0x0A           // 1010
+  };
+
+  enum ReservedTag {
+    kReservedTagLong = 0xF  // 1111
+  };
+
+ public:
+  enum Tag {
+    kTagDefault = kMainTagDefault << 2 | kTypeMain,
+    kTagInput = kMainTagInput << 2 | kTypeMain,
+    kTagOutput = kMainTagOutput << 2 | kTypeMain,
+    kTagFeature = kMainTagFeature << 2 | kTypeMain,
+    kTagCollection = kMainTagCollection << 2 | kTypeMain,
+    kTagEndCollection = kMainTagEndCollection << 2 | kTypeMain,
+    kTagUsagePage = kGlobalTagUsagePage << 2 | kTypeGlobal,
+    kTagLogicalMinimum = kGlobalTagLogicalMinimum << 2 | kTypeGlobal,
+    kTagLogicalMaximum = kGlobalTagLogicalMaximum << 2 | kTypeGlobal,
+    kTagPhysicalMinimum = kGlobalTagPhysicalMinimum << 2 | kTypeGlobal,
+    kTagPhysicalMaximum = kGlobalTagPhysicalMaximum << 2 | kTypeGlobal,
+    kTagUnitExponent = kGlobalTagUnitExponent << 2 | kTypeGlobal,
+    kTagUnit = kGlobalTagUnit << 2 | kTypeGlobal,
+    kTagReportSize = kGlobalTagReportSize << 2 | kTypeGlobal,
+    kTagReportId = kGlobalTagReportId << 2 | kTypeGlobal,
+    kTagReportCount = kGlobalTagReportCount << 2 | kTypeGlobal,
+    kTagPush = kGlobalTagPush << 2 | kTypeGlobal,
+    kTagPop = kGlobalTagPop << 2 | kTypeGlobal,
+    kTagUsage = kLocalTagUsage << 2 | kTypeLocal,
+    kTagUsageMinimum = kLocalTagUsageMinimum << 2 | kTypeLocal,
+    kTagUsageMaximum = kLocalTagUsageMaximum << 2 | kTypeLocal,
+    kTagDesignatorIndex = kLocalTagDesignatorIndex << 2 | kTypeLocal,
+    kTagDesignatorMinimum = kLocalTagDesignatorMinimum << 2 | kTypeLocal,
+    kTagDesignatorMaximum = kLocalTagDesignatorMaximum << 2 | kTypeLocal,
+    kTagStringIndex = kLocalTagStringIndex << 2 | kTypeLocal,
+    kTagStringMinimum = kLocalTagStringMinimum << 2 | kTypeLocal,
+    kTagStringMaximum = kLocalTagStringMaximum << 2 | kTypeLocal,
+    kTagDelimiter = kLocalTagDelimiter << 2 | kTypeLocal,
+    kTagLong = kReservedTagLong << 2 | kTypeReserved
+  };
+
+  // HID Input/Output/Feature report information.
+  // Can be retrieved from GetShortData()
+  // when item.tag() == HidReportDescriptorItem::kTagInput
+  // or HidReportDescriptorItem::kTagOutput
+  // or HidReportDescriptorItem::kTagFeature
+  struct ReportInfo {
+    uint8_t data_or_constant : 1;
+    uint8_t array_or_variable : 1;
+    uint8_t absolute_or_relative : 1;
+    uint8_t wrap : 1;
+    uint8_t linear : 1;
+    uint8_t preferred : 1;
+    uint8_t null : 1;
+    uint8_t reserved_1 : 1;
+    uint8_t bit_field_or_buffer : 1;
+    uint8_t reserved_2 : 1;
+  };
+
+  // HID collection type.
+  // Can be retrieved from GetShortData()
+  // when item.tag() == HidReportDescriptorItem::kTagCollection
+  enum CollectionType {
+    kCollectionTypePhysical,
+    kCollectionTypeApplication,
+    kCollectionTypeLogical,
+    kCollectionTypeReport,
+    kCollectionTypeNamedArray,
+    kCollectionTypeUsageSwitch,
+    kCollectionTypeUsageModifier,
+    kCollectionTypeReserved,
+    kCollectionTypeVendor
+  };
+
+ private:
+  HidReportDescriptorItem(const uint8_t* bytes,
+                          HidReportDescriptorItem* previous);
+
+ public:
+  ~HidReportDescriptorItem() {}
+
+  // Previous element in report descriptor.
+  // Owned by descriptor instance.
+  HidReportDescriptorItem* previous() const {
+    return previous_;
+  };
+  // Next element in report descriptor.
+  // Owned by descriptor instance.
+  HidReportDescriptorItem* next() const {
+    return next_;
+  };
+  // Parent element in report descriptor.
+  // Owned by descriptor instance.
+  // Can be NULL.
+  HidReportDescriptorItem* parent() const {
+    return parent_;
+  };
+  // Level in Parent-Children relationship tree.
+  // 0 for top-level items (parent()==NULL).
+  // 1 if parent() is top-level.
+  // 2 if parent() has a top-level parent. Etc.
+  size_t GetDepth() const;
+  Tag tag() const { return tag_; }
+  // Returns true for a long item, false otherwise.
+  bool IsLong() const;
+  // Raw data of a short item.
+  // Not valid for a long item.
+  uint32_t GetShortData() const;
+
+  static CollectionType GetCollectionTypeFromValue(uint32_t value);
+
+ private:
+  size_t GetHeaderSize() const;
+  size_t payload_size() const { return payload_size_; }
+  size_t GetSize() const;
+
+  HidReportDescriptorItem* previous_;
+  HidReportDescriptorItem* next_;
+  HidReportDescriptorItem* parent_;
+  Tag tag_;
+  uint32_t shortData_;
+  size_t payload_size_;
+};
+
+}  // namespace device
+
+#endif  // DEVICE_HID_HID_REPORT_DESCRIPTOR_ITEM_H_