Source
pub fn alloc(ctx: *anyopaque, n: usize, alignment: mem.Alignment, ra: usize) ?[*]u8 {
const self: *FixedBufferAllocator = @ptrCast(@alignCast(ctx));
_ = ra;
const ptr_align = alignment.toByteUnits();
const adjust_off = mem.alignPointerOffset(self.buffer.ptr + self.end_index, ptr_align) orelse return null;
const adjusted_index = self.end_index + adjust_off;
const new_end_index = adjusted_index + n;
if (new_end_index > self.buffer.len) return null;
self.end_index = new_end_index;
return self.buffer.ptr + adjusted_index;
}