const std = @import("../std.zig");
const Allocator = std.mem.Allocator;
pub fn LogToWriterAllocator(comptime Writer: type) type {
return struct {
parent_allocator: Allocator,
writer: Writer,
const Self = @This();
pub fn init(parent_allocator: Allocator, writer: Writer) Self {
return Self{
.parent_allocator = parent_allocator,
.writer = writer,
};
}
pub fn allocator(self: *Self) Allocator {
return Allocator.init(self, alloc, resize, free);
}
fn alloc(
self: *Self,
len: usize,
ptr_align: u29,
len_align: u29,
ra: usize,
) error{OutOfMemory}![]u8 {
self.writer.print("alloc : {}", .{len}) catch {};
const result = self.parent_allocator.rawAlloc(len, ptr_align, len_align, ra);
if (result) |_| {
self.writer.print(" success!\n", .{}) catch {};
} else |_| {
self.writer.print(" failure!\n", .{}) catch {};
}
return result;
}
fn resize(
self: *Self,
buf: []u8,
buf_align: u29,
new_len: usize,
len_align: u29,
ra: usize,
) ?usize {
if (new_len <= buf.len) {
self.writer.print("shrink: {} to {}\n", .{ buf.len, new_len }) catch {};
} else {
self.writer.print("expand: {} to {}", .{ buf.len, new_len }) catch {};
}
if (self.parent_allocator.rawResize(buf, buf_align, new_len, len_align, ra)) |resized_len| {
if (new_len > buf.len) {
self.writer.print(" success!\n", .{}) catch {};
}
return resized_len;
}
std.debug.assert(new_len > buf.len);
self.writer.print(" failure!\n", .{}) catch {};
return null;
}
fn free(
self: *Self,
buf: []u8,
buf_align: u29,
ra: usize,
) void {
self.writer.print("free : {}\n", .{buf.len}) catch {};
self.parent_allocator.rawFree(buf, buf_align, ra);
}
};
}
pub fn logToWriterAllocator(
parent_allocator: Allocator,
writer: anytype,
) LogToWriterAllocator(@TypeOf(writer)) {
return LogToWriterAllocator(@TypeOf(writer)).init(parent_allocator, writer);
}
test "LogToWriterAllocator" {
var log_buf: [255]u8 = undefined;
var fbs = std.io.fixedBufferStream(&log_buf);
var allocator_buf: [10]u8 = undefined;
var fixedBufferAllocator = std.mem.validationWrap(std.heap.FixedBufferAllocator.init(&allocator_buf));
var allocator_state = logToWriterAllocator(fixedBufferAllocator.allocator(), fbs.writer());
const allocator = allocator_state.allocator();
var a = try allocator.alloc(u8, 10);
a = allocator.shrink(a, 5);
try std.testing.expect(a.len == 5);
try std.testing.expect(allocator.resize(a, 20) == null);
allocator.free(a);
try std.testing.expectEqualSlices(u8,
\\alloc : 10 success!
\\shrink: 10 to 5
\\expand: 5 to 20 failure!
\\free : 5
\\
, fbs.getWritten());
}