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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");
}
}
}
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