const std = @import("std"); pub const File = struct { ptr: []align(std.mem.page_size) u8, len: u64, allocator: std.mem.Allocator, pub fn init(fd: std.os.fd_t, allocator: std.mem.Allocator) !File { var stats = try std.os.fstat(fd); var ptr = try std.os.mmap(null, @intCast(usize, stats.size), std.os.PROT.READ | std.os.PROT.WRITE, std.os.MAP.SHARED, fd, 0); return File{ .ptr = ptr, .len = @intCast(u64, stats.size), .allocator = allocator }; } pub fn deinit(self: *File) void { std.os.munmap(self.ptr); self.ptr = undefined; self.len = 0; } }; pub fn main() !void { var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator); defer arena.deinit(); const allocator = arena.allocator(); const args = try std.process.argsAlloc(allocator); if (args.len != 2) { std.debug.print("usage: {s} file\n", .{args[0]}); std.os.exit(1); } const path = args[1]; // mmap input var fd = try std.os.open(path, std.os.O.RDWR, 0); var input = try File.init(fd, allocator); defer input.deinit(); // search for /nix/store var i: usize = 0; const needle = "/nix/store/"; while (std.mem.indexOfPos(u8, input.ptr, i, needle)) |idx| { i = idx + needle.len; var j = i + 32; // pos of - in a true path if (j < input.len and input.ptr[j] == '-') { std.mem.copy(u8, input.ptr[i..], "00000000000000000000000000000000"); } } }