zig/std/debug/failing_allocator.zig
Jimmi Holst Christensen 8139c5a516
New Zig formal grammar (#1685)
Reverted #1628 and changed the grammar+parser of the language to not allow certain expr where types are expected
2018-11-13 05:08:37 -08:00

65 lines
2.3 KiB
Zig

const std = @import("../index.zig");
const mem = std.mem;
/// Allocator that fails after N allocations, useful for making sure out of
/// memory conditions are handled correctly.
pub const FailingAllocator = struct {
allocator: mem.Allocator,
index: usize,
fail_index: usize,
internal_allocator: *mem.Allocator,
allocated_bytes: usize,
freed_bytes: usize,
deallocations: usize,
pub fn init(allocator: *mem.Allocator, fail_index: usize) FailingAllocator {
return FailingAllocator{
.internal_allocator = allocator,
.fail_index = fail_index,
.index = 0,
.allocated_bytes = 0,
.freed_bytes = 0,
.deallocations = 0,
.allocator = mem.Allocator{
.allocFn = alloc,
.reallocFn = realloc,
.freeFn = free,
},
};
}
fn alloc(allocator: *mem.Allocator, n: usize, alignment: u29) ![]u8 {
const self = @fieldParentPtr(FailingAllocator, "allocator", allocator);
if (self.index == self.fail_index) {
return error.OutOfMemory;
}
const result = try self.internal_allocator.allocFn(self.internal_allocator, n, alignment);
self.allocated_bytes += result.len;
self.index += 1;
return result;
}
fn realloc(allocator: *mem.Allocator, old_mem: []u8, new_size: usize, alignment: u29) ![]u8 {
const self = @fieldParentPtr(FailingAllocator, "allocator", allocator);
if (new_size <= old_mem.len) {
self.freed_bytes += old_mem.len - new_size;
return self.internal_allocator.reallocFn(self.internal_allocator, old_mem, new_size, alignment);
}
if (self.index == self.fail_index) {
return error.OutOfMemory;
}
const result = try self.internal_allocator.reallocFn(self.internal_allocator, old_mem, new_size, alignment);
self.allocated_bytes += new_size - old_mem.len;
self.deallocations += 1;
self.index += 1;
return result;
}
fn free(allocator: *mem.Allocator, bytes: []u8) void {
const self = @fieldParentPtr(FailingAllocator, "allocator", allocator);
self.freed_bytes += bytes.len;
self.deallocations += 1;
return self.internal_allocator.freeFn(self.internal_allocator, bytes);
}
};