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Diffstat (limited to 'third_party/libwebrtc/modules/include/module_common_types_public.h')
-rw-r--r-- | third_party/libwebrtc/modules/include/module_common_types_public.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/include/module_common_types_public.h b/third_party/libwebrtc/modules/include/module_common_types_public.h new file mode 100644 index 0000000000..5a6f634df7 --- /dev/null +++ b/third_party/libwebrtc/modules/include/module_common_types_public.h @@ -0,0 +1,62 @@ +/* + * Copyright (c) 2017 The WebRTC project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef MODULES_INCLUDE_MODULE_COMMON_TYPES_PUBLIC_H_ +#define MODULES_INCLUDE_MODULE_COMMON_TYPES_PUBLIC_H_ + +#include <limits> + +#include "absl/types/optional.h" + +namespace webrtc { + +template <typename U> +inline bool IsNewer(U value, U prev_value) { + static_assert(!std::numeric_limits<U>::is_signed, "U must be unsigned"); + // kBreakpoint is the half-way mark for the type U. For instance, for a + // uint16_t it will be 0x8000, and for a uint32_t, it will be 0x8000000. + constexpr U kBreakpoint = (std::numeric_limits<U>::max() >> 1) + 1; + // Distinguish between elements that are exactly kBreakpoint apart. + // If t1>t2 and |t1-t2| = kBreakpoint: IsNewer(t1,t2)=true, + // IsNewer(t2,t1)=false + // rather than having IsNewer(t1,t2) = IsNewer(t2,t1) = false. + if (value - prev_value == kBreakpoint) { + return value > prev_value; + } + return value != prev_value && + static_cast<U>(value - prev_value) < kBreakpoint; +} + +// NB: Doesn't fulfill strict weak ordering requirements. +// Mustn't be used as std::map Compare function. +inline bool IsNewerSequenceNumber(uint16_t sequence_number, + uint16_t prev_sequence_number) { + return IsNewer(sequence_number, prev_sequence_number); +} + +// NB: Doesn't fulfill strict weak ordering requirements. +// Mustn't be used as std::map Compare function. +inline bool IsNewerTimestamp(uint32_t timestamp, uint32_t prev_timestamp) { + return IsNewer(timestamp, prev_timestamp); +} + +inline uint16_t LatestSequenceNumber(uint16_t sequence_number1, + uint16_t sequence_number2) { + return IsNewerSequenceNumber(sequence_number1, sequence_number2) + ? sequence_number1 + : sequence_number2; +} + +inline uint32_t LatestTimestamp(uint32_t timestamp1, uint32_t timestamp2) { + return IsNewerTimestamp(timestamp1, timestamp2) ? timestamp1 : timestamp2; +} + +} // namespace webrtc +#endif // MODULES_INCLUDE_MODULE_COMMON_TYPES_PUBLIC_H_ |