struct Cursor {
explicit Cursor(uint64_t initialTicket) noexcept : ticket(initialTicket) {}
- void moveForward(uint64_t steps = 1) noexcept {
+ /// Returns true if this cursor now points to a different
+ /// write, false otherwise.
+ bool moveForward(uint64_t steps = 1) noexcept {
+ uint64_t prevTicket = ticket;
ticket += steps;
+ return prevTicket != ticket;
}
- void moveBackward(uint64_t steps = 1) noexcept {
+ /// Returns true if this cursor now points to a previous
+ /// write, false otherwise.
+ bool moveBackward(uint64_t steps = 1) noexcept {
+ uint64_t prevTicket = ticket;
if (steps > ticket) {
ticket = 0;
} else {
ticket -= steps;
}
+ return prevTicket != ticket;
}
protected: // for test visibility reasons