| // Copyright 2018 The Fuchsia Authors |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #pragma once |
| |
| #include <zircon/compiler.h> |
| #include <zircon/types.h> |
| |
| // These functions perform overflow-safe time arithmetic, clamping to ZX_TIME_INFINITE in case of |
| // overflow and ZX_TIME_INFINITE_PAST in case of underflow. |
| // |
| // C++ code should use zx::time and zx::duration instead. |
| // |
| // The naming scheme is zx_<first argument>_<operation>_<second argument>. |
| // |
| // TODO(maniscalco): Consider expanding the set of operations to include division, modulo, unit |
| // conversion, and floating point math. |
| |
| __CONSTEXPR static inline zx_time_t zx_time_add_duration(zx_time_t time, zx_duration_t duration) { |
| zx_time_t x = 0; |
| if (unlikely(add_overflow(time, duration, &x))) { |
| if (x >= 0) { |
| return ZX_TIME_INFINITE_PAST; |
| } else { |
| return ZX_TIME_INFINITE; |
| } |
| } |
| return x; |
| } |
| |
| __CONSTEXPR static inline zx_time_t zx_time_sub_duration(zx_time_t time, zx_duration_t duration) { |
| zx_time_t x = 0; |
| if (unlikely(sub_overflow(time, duration, &x))) { |
| if (x >= 0) { |
| return ZX_TIME_INFINITE_PAST; |
| } else { |
| return ZX_TIME_INFINITE; |
| } |
| |
| } |
| return x; |
| } |
| |
| __CONSTEXPR static inline zx_duration_t zx_time_sub_time(zx_time_t time1, zx_time_t time2) { |
| zx_duration_t x = 0; |
| if (unlikely(sub_overflow(time1, time2, &x))) { |
| if (x >= 0) { |
| return ZX_TIME_INFINITE_PAST; |
| } else { |
| return ZX_TIME_INFINITE; |
| } |
| } |
| return x; |
| } |
| |
| __CONSTEXPR static inline zx_duration_t zx_duration_add_duration(zx_duration_t dur1, |
| zx_duration_t dur2) { |
| zx_duration_t x = 0; |
| if (unlikely(add_overflow(dur1, dur2, &x))) { |
| if (x >= 0) { |
| return ZX_TIME_INFINITE_PAST; |
| } else { |
| return ZX_TIME_INFINITE; |
| } |
| } |
| return x; |
| } |
| |
| __CONSTEXPR static inline zx_duration_t zx_duration_sub_duration(zx_duration_t dur1, |
| zx_duration_t dur2) { |
| zx_duration_t x = 0; |
| if (unlikely(sub_overflow(dur1, dur2, &x))) { |
| if (x >= 0) { |
| return ZX_TIME_INFINITE_PAST; |
| } else { |
| return ZX_TIME_INFINITE; |
| } |
| } |
| return x; |
| } |
| |
| __CONSTEXPR static inline zx_duration_t zx_duration_mul_int64(zx_duration_t duration, |
| int64_t multiplier) { |
| zx_duration_t x = 0; |
| if (unlikely(mul_overflow(duration, multiplier, &x))) { |
| if ((duration > 0 && multiplier > 0) || (duration < 0 && multiplier < 0)) { |
| return ZX_TIME_INFINITE; |
| } else { |
| return ZX_TIME_INFINITE_PAST; |
| } |
| } |
| return x; |
| } |