module Std::Map {

extern func bux_hash_string(s: String) -> uint;

struct MapEntry {
    key: String,
    value: int,
    occupied: bool,
}

struct Map {
    entries: *MapEntry,
    cap: uint,
    len: uint,
}

func Map_New(cap: uint) -> Map {
    let total: uint = cap * sizeof(MapEntry);
    let data: *MapEntry = bux_alloc(total) as *MapEntry;
    var i: uint = 0;
    while i < cap {
        data[i].occupied = false;
        i = i + 1;
    }
    return Map { entries: data, cap: cap, len: 0 };
}

func Map_Set(m: *Map, key: String, value: int) {
    let hash: uint = bux_hash_string(key);
    var idx: uint = hash % m.cap;
    while m.entries[idx].occupied {
        if String_Eq(m.entries[idx].key, key) {
            m.entries[idx].value = value;
            return;
        }
        idx = (idx + 1) % m.cap;
    }
    m.entries[idx].key = key;
    m.entries[idx].value = value;
    m.entries[idx].occupied = true;
    m.len = m.len + 1;
}

func Map_Get(m: *Map, key: String) -> int {
    let hash: uint = bux_hash_string(key);
    var idx: uint = hash % m.cap;
    while m.entries[idx].occupied {
        if String_Eq(m.entries[idx].key, key) {
            return m.entries[idx].value;
        }
        idx = (idx + 1) % m.cap;
    }
    return 0;
}

func Map_Has(m: *Map, key: String) -> bool {
    let hash: uint = bux_hash_string(key);
    var idx: uint = hash % m.cap;
    while m.entries[idx].occupied {
        if String_Eq(m.entries[idx].key, key) {
            return true;
        }
        idx = (idx + 1) % m.cap;
    }
    return false;
}

func Map_Len(m: *Map) -> uint {
    return m.len;
}

func Map_Free(m: *Map) {
    bux_free(m.entries as *void);
    m.entries = null as *MapEntry;
    m.cap = 0;
    m.len = 0;
}

}