1563425 - Implement basic circular byte buffer with iterator and LEB128 helpers

Status: RESOLVED FIXED

(Core :: Gecko Profiler, task, P2)

Description

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

The new ProfileBuffer underlying buffer will store variable-sized entries in a circular buffer.

That fancy circular buffer will itself use an underlying circular byte buffer, to better separate responsibilities.

Comment 1

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Attachment: Bug 1563425 - ModuloBuffer is a basic circular byte buffer with iterator and LEB128 helpers - r?gregtatum

Basic usage: (Silly examples)

• Create buffer: ModuloBuffer mb(PowerOfTwo);
• Get iterator: auto writer = mb.WriterAt(Index); (or ReaderAt())
• Basic iterator functions on bytes: *++writer = 'x';
• Write: writer.WriteULEB128(sizeof(int)); writer.WriteObject<int>(42);
• Comparisons, move: while (writer > reader) { --writer; }
• Read: size_t s = reader.ReadLEB128<size_t>(); int i = ReadObject<int>();

There are no safety checks, it will be up to the caller to ensure thread-safety,
and data safety when wrapping around the buffer.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3f48535246db
ModuloBuffer is a basic circular byte buffer with iterator and LEB128 helpers - r=gregtatum

Comment 3

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/3f48535246db