https://github.com/lun-4/expiring-hash-map.zig

need a cache or you're limited by memory in your long-lived zig code, well fear no more!
https://github.com/lun-4/expiring-hash-map.zig

zig

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need a cache or you're limited by memory in your long-lived zig code, well fear no more!

• Host: GitHub
• URL: https://github.com/lun-4/expiring-hash-map.zig
• Owner: lun-4
• License: mit
• Created: 2022-07-28T01:20:33.000Z (over 2 years ago)
• Default Branch: mistress
• Last Pushed: 2024-05-12T20:28:22.000Z (9 months ago)
• Last Synced: 2024-12-01T10:54:17.036Z (about 2 months ago)
• Topics: zig
• Language: Zig
• Homepage:
• Size: 7.81 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# expiring-hash-map.zig

need a cache or you're limited by memory in your long-lived zig code, well fear no more!

this doesn't implement all of the HashMap API, but it is good enough

for my usecases (https://github.com/lun-4/awtfdb).

## basically, it goes like this

```zig

// This hash map will hold at most 100 items, and if any of the items

// life for longer than a second, they will be removed

// to do so, get() and put() return more than just the value type, so that

// the caller can determine when to free the given memory (if the value

// has pointers that are heap allocated).

const EHM = ExpiringHashMap(1 * std.time.ns_per_s, 100, usize, usize);

var ehm = EHM.init(std.testing.allocator);

defer ehm.deinit();

// returns null

ehm.get(123);

// since we didn't have anything in the map, ignore the list of things to remove

_ = try ehm.put(123, 456);

// returns a wrapper type (?MaybeV) containing 456 as a non-expired value

var maybe_value = ehm.get(123);

maybe_value.has_value; // assert that there's a value

// sneaky sleep

std.time.sleep(1 * std.time.ns_per_s);

// now the value is expired.

var maybe_value = ehm.get(123);

maybe_value.has_value; // will error

maybe_value.expired; // returns the value, 456

// now, if i add a value, wait, and add another, the first one should be expired

_ = try ehm.put(123, 456);

std.time.sleep(1 * std.time.ns_per_s);

var to_remove = try ehm.put(127, 457);

for (to_remove) |value| do_something_to_free_this(value);

```