| ... | ... | @@ -321,51 +321,57 @@ pub const FixedBufferAllocator = struct { |
| 321 | 321 | fn free(allocator: *Allocator, bytes: []u8) void {} |
| 322 | 322 | }; |
| 323 | 323 | |
| 324 | | /// lock free |
| 325 | | pub const ThreadSafeFixedBufferAllocator = struct { |
| 326 | | allocator: Allocator, |
| 327 | | end_index: usize, |
| 328 | | buffer: []u8, |
| 324 | pub const ThreadSafeFixedBufferAllocator = blk: { |
| 325 | if (builtin.single_threaded) { |
| 326 | break :blk FixedBufferAllocator; |
| 327 | } else { |
| 328 | /// lock free |
| 329 | break :blk struct { |
| 330 | allocator: Allocator, |
| 331 | end_index: usize, |
| 332 | buffer: []u8, |
| 333 | |
| 334 | pub fn init(buffer: []u8) ThreadSafeFixedBufferAllocator { |
| 335 | return ThreadSafeFixedBufferAllocator{ |
| 336 | .allocator = Allocator{ |
| 337 | .allocFn = alloc, |
| 338 | .reallocFn = realloc, |
| 339 | .freeFn = free, |
| 340 | }, |
| 341 | .buffer = buffer, |
| 342 | .end_index = 0, |
| 343 | }; |
| 344 | } |
| 329 | 345 | |
| 330 | | pub fn init(buffer: []u8) ThreadSafeFixedBufferAllocator { |
| 331 | | return ThreadSafeFixedBufferAllocator{ |
| 332 | | .allocator = Allocator{ |
| 333 | | .allocFn = alloc, |
| 334 | | .reallocFn = realloc, |
| 335 | | .freeFn = free, |
| 336 | | }, |
| 337 | | .buffer = buffer, |
| 338 | | .end_index = 0, |
| 339 | | }; |
| 340 | | } |
| 346 | fn alloc(allocator: *Allocator, n: usize, alignment: u29) ![]u8 { |
| 347 | const self = @fieldParentPtr(ThreadSafeFixedBufferAllocator, "allocator", allocator); |
| 348 | var end_index = @atomicLoad(usize, &self.end_index, builtin.AtomicOrder.SeqCst); |
| 349 | while (true) { |
| 350 | const addr = @ptrToInt(self.buffer.ptr) + end_index; |
| 351 | const rem = @rem(addr, alignment); |
| 352 | const march_forward_bytes = if (rem == 0) 0 else (alignment - rem); |
| 353 | const adjusted_index = end_index + march_forward_bytes; |
| 354 | const new_end_index = adjusted_index + n; |
| 355 | if (new_end_index > self.buffer.len) { |
| 356 | return error.OutOfMemory; |
| 357 | } |
| 358 | end_index = @cmpxchgWeak(usize, &self.end_index, end_index, new_end_index, builtin.AtomicOrder.SeqCst, builtin.AtomicOrder.SeqCst) orelse return self.buffer[adjusted_index..new_end_index]; |
| 359 | } |
| 360 | } |
| 341 | 361 | |
| 342 | | fn alloc(allocator: *Allocator, n: usize, alignment: u29) ![]u8 { |
| 343 | | const self = @fieldParentPtr(ThreadSafeFixedBufferAllocator, "allocator", allocator); |
| 344 | | var end_index = @atomicLoad(usize, &self.end_index, builtin.AtomicOrder.SeqCst); |
| 345 | | while (true) { |
| 346 | | const addr = @ptrToInt(self.buffer.ptr) + end_index; |
| 347 | | const rem = @rem(addr, alignment); |
| 348 | | const march_forward_bytes = if (rem == 0) 0 else (alignment - rem); |
| 349 | | const adjusted_index = end_index + march_forward_bytes; |
| 350 | | const new_end_index = adjusted_index + n; |
| 351 | | if (new_end_index > self.buffer.len) { |
| 352 | | return error.OutOfMemory; |
| 362 | fn realloc(allocator: *Allocator, old_mem: []u8, new_size: usize, alignment: u29) ![]u8 { |
| 363 | if (new_size <= old_mem.len) { |
| 364 | return old_mem[0..new_size]; |
| 365 | } else { |
| 366 | const result = try alloc(allocator, new_size, alignment); |
| 367 | mem.copy(u8, result, old_mem); |
| 368 | return result; |
| 369 | } |
| 353 | 370 | } |
| 354 | | end_index = @cmpxchgWeak(usize, &self.end_index, end_index, new_end_index, builtin.AtomicOrder.SeqCst, builtin.AtomicOrder.SeqCst) orelse return self.buffer[adjusted_index..new_end_index]; |
| 355 | | } |
| 356 | | } |
| 357 | 371 | |
| 358 | | fn realloc(allocator: *Allocator, old_mem: []u8, new_size: usize, alignment: u29) ![]u8 { |
| 359 | | if (new_size <= old_mem.len) { |
| 360 | | return old_mem[0..new_size]; |
| 361 | | } else { |
| 362 | | const result = try alloc(allocator, new_size, alignment); |
| 363 | | mem.copy(u8, result, old_mem); |
| 364 | | return result; |
| 365 | | } |
| 372 | fn free(allocator: *Allocator, bytes: []u8) void {} |
| 373 | }; |
| 366 | 374 | } |
| 367 | | |
| 368 | | fn free(allocator: *Allocator, bytes: []u8) void {} |
| 369 | 375 | }; |
| 370 | 376 | |
| 371 | 377 | pub fn stackFallback(comptime size: usize, fallback_allocator: *Allocator) StackFallbackAllocator(size) { |
John Schmidt <john.schmidt.h@gmail.com> 2019-02-07 21:28:37+01:00
Andrew Kelley <andrew@ziglang.org> 2019-02-07 23:21:37-05:00
std