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d29871977f
We already have a LICENSE file that covers the Zig Standard Library. We no longer need to remind everyone that the license is MIT in every single file. Previously this was introduced to clarify the situation for a fork of Zig that made Zig's LICENSE file harder to find, and replaced it with their own license that required annual payments to their company. However that fork now appears to be dead. So there is no need to reinforce the copyright notice in every single file.
90 lines
3.0 KiB
Zig
90 lines
3.0 KiB
Zig
const std = @import("../std.zig");
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const mem = std.mem;
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/// Allocator that fails after N allocations, useful for making sure out of
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/// memory conditions are handled correctly.
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///
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/// To use this, first initialize it and get an allocator with
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///
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/// `const failing_allocator = &FailingAllocator.init(<allocator>,
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/// <fail_index>).allocator;`
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///
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/// Then use `failing_allocator` anywhere you would have used a
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/// different allocator.
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pub const FailingAllocator = struct {
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allocator: mem.Allocator,
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index: usize,
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fail_index: usize,
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internal_allocator: *mem.Allocator,
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allocated_bytes: usize,
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freed_bytes: usize,
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allocations: usize,
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deallocations: usize,
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/// `fail_index` is the number of successful allocations you can
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/// expect from this allocator. The next allocation will fail.
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/// For example, if this is called with `fail_index` equal to 2,
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/// the following test will pass:
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///
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/// var a = try failing_alloc.create(i32);
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/// var b = try failing_alloc.create(i32);
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/// testing.expectError(error.OutOfMemory, failing_alloc.create(i32));
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pub fn init(allocator: *mem.Allocator, fail_index: usize) FailingAllocator {
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return FailingAllocator{
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.internal_allocator = allocator,
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.fail_index = fail_index,
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.index = 0,
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.allocated_bytes = 0,
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.freed_bytes = 0,
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.allocations = 0,
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.deallocations = 0,
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.allocator = mem.Allocator{
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.allocFn = alloc,
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.resizeFn = resize,
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},
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};
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}
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fn alloc(
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allocator: *std.mem.Allocator,
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len: usize,
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ptr_align: u29,
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len_align: u29,
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return_address: usize,
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) error{OutOfMemory}![]u8 {
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const self = @fieldParentPtr(FailingAllocator, "allocator", allocator);
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if (self.index == self.fail_index) {
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return error.OutOfMemory;
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}
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const result = try self.internal_allocator.allocFn(self.internal_allocator, len, ptr_align, len_align, return_address);
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self.allocated_bytes += result.len;
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self.allocations += 1;
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self.index += 1;
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return result;
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}
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fn resize(
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allocator: *std.mem.Allocator,
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old_mem: []u8,
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old_align: u29,
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new_len: usize,
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len_align: u29,
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ra: usize,
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) error{OutOfMemory}!usize {
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const self = @fieldParentPtr(FailingAllocator, "allocator", allocator);
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const r = self.internal_allocator.resizeFn(self.internal_allocator, old_mem, old_align, new_len, len_align, ra) catch |e| {
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std.debug.assert(new_len > old_mem.len);
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return e;
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};
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if (new_len == 0) {
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self.deallocations += 1;
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self.freed_bytes += old_mem.len;
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} else if (r < old_mem.len) {
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self.freed_bytes += old_mem.len - r;
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} else {
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self.allocated_bytes += r - old_mem.len;
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}
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return r;
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}
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};
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