text: // Copyright 2014 The Crashpad Authors. All rights reserved.
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #if !defined(__STDC_FORMAT_MACROS)
  #define __STDC_FORMAT_MACROS
  #endif
  
  #include "util/misc/uuid.h"
  
  #include <inttypes.h>
  #include <stdio.h>
  #include <string.h>
  
  #include "base/logging.h"
  #include "base/rand_util.h"
  #include "base/strings/stringprintf.h"
  #include "base/strings/utf_string_conversions.h"
  #include "base/sys_byteorder.h"
  #include "util/stdlib/cxx.h"
  
  #if defined(OS_MACOSX)
  #include <uuid/uuid.h>
  #endif  // OS_MACOSX
  
  #if CXX_LIBRARY_VERSION >= 2011
  #include <type_traits>
  #endif
  
  namespace crashpad {
  
  static_assert(sizeof(UUID) == 16, "UUID must be 16 bytes");
  
  #if CXX_LIBRARY_VERSION >= 2011
  static_assert(std::is_pod<UUID>::value, "UUID must be POD");
  #endif
  
  bool UUID::operator==(const UUID& that) const {
    return memcmp(this, &that, sizeof(*this)) == 0;
  }
  
  void UUID::InitializeToZero() {
    memset(this, 0, sizeof(*this));
  }
  
  void UUID::InitializeFromBytes(const uint8_t* bytes) {
    memcpy(this, bytes, sizeof(*this));
    data_1 = base::NetToHost32(data_1);
    data_2 = base::NetToHost16(data_2);
    data_3 = base::NetToHost16(data_3);
  }
  
  bool UUID::InitializeFromString(const base::StringPiece& string) {
    if (string.length() != 36)
      return false;
  
    UUID temp;
    const char kScanFormat[] =
        "%08" SCNx32 "-%04" SCNx16 "-%04" SCNx16
        "-%02" SCNx8 "%02" SCNx8
        "-%02" SCNx8 "%02" SCNx8 "%02" SCNx8 "%02" SCNx8 "%02" SCNx8 "%02" SCNx8;
    int rv = sscanf(string.data(),
                    kScanFormat,
                    &temp.data_1,
                    &temp.data_2,
                    &temp.data_3,
                    &temp.data_4[0],
                    &temp.data_4[1],
                    &temp.data_5[0],
                    &temp.data_5[1],
                    &temp.data_5[2],
                    &temp.data_5[3],
                    &temp.data_5[4],
                    &temp.data_5[5]);
    if (rv != 11)
      return false;
  
    *this = temp;
    return true;
  }
  
  bool UUID::InitializeWithNew() {
  #if defined(OS_MACOSX)
    uuid_t uuid;
    uuid_generate(uuid);
    InitializeFromBytes(uuid);
    return true;
  #elif defined(OS_WIN) || defined(OS_LINUX) || defined(OS_ANDROID)
    // Linux does not provide a UUID generator in a widely-available system
    // library. uuid_generate() from libuuid is not available everywhere.
    // On Windows, do not use UuidCreate() to avoid a dependency on rpcrt4, so
    // that this function is usable early in DllMain().
    base::RandBytes(this, sizeof(*this));
  
    // Set six bits per RFC 4122 §4.4 to identify this as a pseudo-random UUID.
    data_3 = (4 << 12) | (data_3 & 0x0fff);  // §4.1.3
    data_4[0] = 0x80 | (data_4[0] & 0x3f);  // §4.1.1
  
    return true;
  #else
  #error Port.
  #endif  // OS_MACOSX
  }
  
  #if defined(OS_WIN)
  void UUID::InitializeFromSystemUUID(const ::UUID* system_uuid) {
    static_assert(sizeof(::UUID) == sizeof(UUID),
                  "unexpected system uuid size");
    static_assert(offsetof(::UUID, Data1) == offsetof(UUID, data_1),
                  "unexpected system uuid layout");
    memcpy(this, system_uuid, sizeof(*this));
  }
  #endif  // OS_WIN
  
  std::string UUID::ToString() const {
    return base::StringPrintf("%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
                              data_1,
                              data_2,
                              data_3,
                              data_4[0],
                              data_4[1],
                              data_5[0],
                              data_5[1],
                              data_5[2],
                              data_5[3],
                              data_5[4],
                              data_5[5]);
  }
  
  #if defined(OS_WIN)
  base::string16 UUID::ToString16() const {
    return base::UTF8ToUTF16(ToString());
  }
  #endif  // OS_WIN
  
  }  // namespace crashpad
  