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modpyb.c

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  • map.c 7.03 KiB
    #include <stdint.h>
    #include <stdlib.h>
    #include <assert.h>
    
    #include "misc.h"
    #include "mpconfig.h"
    #include "qstr.h"
    #include "obj.h"
    #include "runtime0.h"
    #include "map.h"
    
    // approximatelly doubling primes; made with Mathematica command: Table[Prime[Floor[(1.7)^n]], {n, 3, 24}]
    // prefixed with zero for the empty case.
    static int doubling_primes[] = {0, 7, 19, 43, 89, 179, 347, 647, 1229, 2297, 4243, 7829, 14347, 26017, 47149, 84947, 152443, 273253, 488399, 869927, 1547173, 2745121, 4861607};
    
    int get_doubling_prime_greater_or_equal_to(int x) {
        for (int i = 0; i < sizeof(doubling_primes) / sizeof(int); i++) {
            if (doubling_primes[i] >= x) {
                return doubling_primes[i];
            }
        }
        // ran out of primes in the table!
        // return something sensible, at least make it odd
        return x | 1;
    }
    
    /******************************************************************************/
    /* map                                                                        */
    
    void mp_map_init(mp_map_t *map, int n) {
        map->alloc = get_doubling_prime_greater_or_equal_to(n + 1);
        map->used = 0;
        map->all_keys_are_qstrs = 1;
        map->table = m_new0(mp_map_elem_t, map->alloc);
    }
    
    mp_map_t *mp_map_new(int n) {
        mp_map_t *map = m_new(mp_map_t, 1);
        mp_map_init(map, n);
        return map;
    }
    
    // Differentiate from mp_map_clear() - semantics is different
    void mp_map_deinit(mp_map_t *map) {
        m_del(mp_map_elem_t, map->table, map->alloc);
        map->used = map->alloc = 0;
    }
    
    void mp_map_free(mp_map_t *map) {
        mp_map_deinit(map);
        m_del_obj(mp_map_t, map);
    }
    
    void mp_map_clear(mp_map_t *map) {
        map->used = 0;
        map->all_keys_are_qstrs = 1;
        machine_uint_t a = map->alloc;
        map->alloc = 0;
        map->table = m_renew(mp_map_elem_t, map->table, a, map->alloc);
        mp_map_elem_t nul = {NULL, NULL};
        for (uint i=0; i<map->alloc; i++) {
            map->table[i] = nul;
        }
    }
    
    static void mp_map_rehash(mp_map_t *map) {
        int old_alloc = map->alloc;
        mp_map_elem_t *old_table = map->table;
        map->alloc = get_doubling_prime_greater_or_equal_to(map->alloc + 1);
        map->used = 0;
        map->all_keys_are_qstrs = 1;
        map->table = m_new0(mp_map_elem_t, map->alloc);
        for (int i = 0; i < old_alloc; i++) {
            if (old_table[i].key != NULL) {
                mp_map_lookup(map, old_table[i].key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = old_table[i].value;
            }
        }
        m_del(mp_map_elem_t, old_table, old_alloc);
    }
    
    mp_map_elem_t* mp_map_lookup(mp_map_t *map, mp_obj_t index, mp_map_lookup_kind_t lookup_kind) {
        machine_uint_t hash;
        hash = mp_obj_hash(index);
        if (map->alloc == 0) {
            if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                mp_map_rehash(map);
            } else {
                return NULL;
            }
        }
        uint pos = hash % map->alloc;
        for (;;) {
            mp_map_elem_t *elem = &map->table[pos];
            if (elem->key == NULL) {
                // not in table
                if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                    if (map->used + 1 >= map->alloc) {
                        // not enough room in table, rehash it
                        mp_map_rehash(map);
                        // restart the search for the new element
                        pos = hash % map->alloc;
                    } else {
                        map->used += 1;
                        elem->key = index;
                        if (!MP_OBJ_IS_QSTR(index)) {
                            map->all_keys_are_qstrs = 0;
                        }
                        return elem;
                    }
                } else {
                    return NULL;
                }
            } else if (elem->key == index || (!map->all_keys_are_qstrs && mp_obj_equal(elem->key, index))) {
                // found it
                /* it seems CPython does not replace the index; try x={True:'true'};x[1]='one';x
                if (add_if_not_found) {
                    elem->key = index;
                }
                */
                if (lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
                    map->used--;
                    // this leaks this memory (but see dict_get_helper)
                    mp_map_elem_t *retval = m_new(mp_map_elem_t, 1);
                    retval->key = elem->key;
                    retval->value = elem->value;
                    elem->key = NULL;
                    elem->value = NULL;
                    return retval;
                }
                return elem;
            } else {
                // not yet found, keep searching in this table
                pos = (pos + 1) % map->alloc;
            }
        }
    }
    
    /******************************************************************************/
    /* set                                                                        */
    
    void mp_set_init(mp_set_t *set, int n) {
        set->alloc = get_doubling_prime_greater_or_equal_to(n + 1);
        set->used = 0;
        set->table = m_new0(mp_obj_t, set->alloc);
    }
    
    static void mp_set_rehash(mp_set_t *set) {
        int old_alloc = set->alloc;
        mp_obj_t *old_table = set->table;
        set->alloc = get_doubling_prime_greater_or_equal_to(set->alloc + 1);
        set->used = 0;
        set->table = m_new0(mp_obj_t, set->alloc);
        for (int i = 0; i < old_alloc; i++) {
            if (old_table[i] != NULL) {
                mp_set_lookup(set, old_table[i], true);
            }
        }
        m_del(mp_obj_t, old_table, old_alloc);
    }
    
    mp_obj_t mp_set_lookup(mp_set_t *set, mp_obj_t index, mp_map_lookup_kind_t lookup_kind) {
        int hash;
        int pos;
        if (set->alloc == 0) {
            if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                mp_set_rehash(set);
            } else {
                return NULL;
            }
        }
        if (lookup_kind & MP_MAP_LOOKUP_FIRST) {
            hash = 0;
            pos = 0;
        } else {
            hash = mp_obj_hash(index);;
            pos = hash % set->alloc;
        }
        for (;;) {
            mp_obj_t elem = set->table[pos];
            if (elem == MP_OBJ_NULL) {
                // not in table
                if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                    if (set->used + 1 >= set->alloc) {
                        // not enough room in table, rehash it
                        mp_set_rehash(set);
                        // restart the search for the new element
                        pos = hash % set->alloc;
                    } else {
                        set->used += 1;
                        set->table[pos] = index;
                        return index;
                    }
                } else if (lookup_kind & MP_MAP_LOOKUP_FIRST) {
                    pos++;
                } else {
                    return MP_OBJ_NULL;
                }
            } else if (lookup_kind & MP_MAP_LOOKUP_FIRST || mp_obj_equal(elem, index)) {
                // found it
                if (lookup_kind & MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
                    set->used--;
                    set->table[pos] = NULL;
                }
                return elem;
            } else {
                // not yet found, keep searching in this table
                pos = (pos + 1) % set->alloc;
            }
        }
    }
    
    void mp_set_clear(mp_set_t *set) {
        set->used = 0;
        machine_uint_t a = set->alloc;
        set->alloc = 0;
        set->table = m_renew(mp_obj_t, set->table, a, set->alloc);
        for (uint i=0; i<set->alloc; i++) {
            set->table[i] = NULL;
        }
    }