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objint.c

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  • map.c 15.06 KiB
    /*
     * This file is part of the Micro Python project, http://micropython.org/
     *
     * The MIT License (MIT)
     *
     * Copyright (c) 2013, 2014 Damien P. George
     *
     * Permission is hereby granted, free of charge, to any person obtaining a copy
     * of this software and associated documentation files (the "Software"), to deal
     * in the Software without restriction, including without limitation the rights
     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     * copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     * THE SOFTWARE.
     */
    
    #include <stdint.h>
    #include <stdlib.h>
    #include <string.h>
    #include <assert.h>
    
    #include "py/mpconfig.h"
    #include "py/misc.h"
    #include "py/runtime0.h"
    #include "py/runtime.h"
    
    // Fixed empty map. Useful when need to call kw-receiving functions
    // without any keywords from C, etc.
    const mp_map_t mp_const_empty_map = {
        .all_keys_are_qstrs = 0,
        .is_fixed = 1,
        .is_ordered = 1,
        .used = 0,
        .alloc = 0,
        .table = NULL,
    };
    
    // This table of sizes is used to control the growth of hash tables.
    // The first set of sizes are chosen so the allocation fits exactly in a
    // 4-word GC block, and it's not so important for these small values to be
    // prime.  The latter sizes are prime and increase at an increasing rate.
    STATIC uint16_t hash_allocation_sizes[] = {
        0, 2, 4, 6, 8, 10, 12, // +2
        17, 23, 29, 37, 47, 59, 73, // *1.25
        97, 127, 167, 223, 293, 389, 521, 691, 919, 1223, 1627, 2161, // *1.33
        3229, 4831, 7243, 10861, 16273, 24407, 36607, 54907, // *1.5
    };
    
    STATIC mp_uint_t get_hash_alloc_greater_or_equal_to(mp_uint_t x) {
        for (size_t i = 0; i < MP_ARRAY_SIZE(hash_allocation_sizes); i++) {
            if (hash_allocation_sizes[i] >= x) {
                return hash_allocation_sizes[i];
            }
        }
        // ran out of primes in the table!
        // return something sensible, at least make it odd
        return (x + x / 2) | 1;
    }
    
    /******************************************************************************/
    /* map                                                                        */
    
    void mp_map_init(mp_map_t *map, mp_uint_t n) {
        if (n == 0) {
            map->alloc = 0;
            map->table = NULL;
        } else {
            map->alloc = n;
            map->table = m_new0(mp_map_elem_t, map->alloc);
        }
        map->used = 0;
        map->all_keys_are_qstrs = 1;
        map->is_fixed = 0;
        map->is_ordered = 0;
    }
    
    void mp_map_init_fixed_table(mp_map_t *map, mp_uint_t n, const mp_obj_t *table) {
        map->alloc = n;
        map->used = n;
        map->all_keys_are_qstrs = 1;
        map->is_fixed = 1;
        map->is_ordered = 1;
        map->table = (mp_map_elem_t*)table;
    }
    
    mp_map_t *mp_map_new(mp_uint_t 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) {
        if (!map->is_fixed) {
            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) {
        if (!map->is_fixed) {
            m_del(mp_map_elem_t, map->table, map->alloc);
        }
        map->alloc = 0;
        map->used = 0;
        map->all_keys_are_qstrs = 1;
        map->is_fixed = 0;
        map->table = NULL;
    }
    
    STATIC void mp_map_rehash(mp_map_t *map) {
        mp_uint_t old_alloc = map->alloc;
        mp_uint_t new_alloc = get_hash_alloc_greater_or_equal_to(map->alloc + 1);
        mp_map_elem_t *old_table = map->table;
        mp_map_elem_t *new_table = m_new0(mp_map_elem_t, new_alloc);
        // If we reach this point, table resizing succeeded, now we can edit the old map.
        map->alloc = new_alloc;
        map->used = 0;
        map->all_keys_are_qstrs = 1;
        map->table = new_table;
        for (mp_uint_t i = 0; i < old_alloc; i++) {
            if (old_table[i].key != MP_OBJ_NULL && old_table[i].key != MP_OBJ_SENTINEL) {
                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_LOOKUP behaviour:
    //  - returns NULL if not found, else the slot it was found in with key,value non-null
    // MP_MAP_LOOKUP_ADD_IF_NOT_FOUND behaviour:
    //  - returns slot, with key non-null and value=MP_OBJ_NULL if it was added
    // MP_MAP_LOOKUP_REMOVE_IF_FOUND behaviour:
    //  - returns NULL if not found, else the slot if was found in with key null and value non-null
    mp_map_elem_t *mp_map_lookup(mp_map_t *map, mp_obj_t index, mp_map_lookup_kind_t lookup_kind) {
    
        if (map->is_fixed && lookup_kind != MP_MAP_LOOKUP) {
            // can't add/remove from a fixed array
            return NULL;
        }
    
        // Work out if we can compare just pointers
        bool compare_only_ptrs = map->all_keys_are_qstrs;
        if (compare_only_ptrs) {
            if (MP_OBJ_IS_QSTR(index)) {
                // Index is a qstr, so can just do ptr comparison.
            } else if (MP_OBJ_IS_TYPE(index, &mp_type_str)) {
                // Index is a non-interned string.
                // We can either intern the string, or force a full equality comparison.
                // We chose the latter, since interning costs time and potentially RAM,
                // and it won't necessarily benefit subsequent calls because these calls
                // most likely won't pass the newly-interned string.
                compare_only_ptrs = false;
            } else if (lookup_kind != MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                // If we are not adding, then we can return straight away a failed
                // lookup because we know that the index will never be found.
                return NULL;
            }
        }
    
        // if the map is an ordered array then we must do a brute force linear search
        if (map->is_ordered) {
            for (mp_map_elem_t *elem = &map->table[0], *top = &map->table[map->used]; elem < top; elem++) {
                if (elem->key == index || (!compare_only_ptrs && mp_obj_equal(elem->key, index))) {
                    if (MP_UNLIKELY(lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND)) {
                        elem->key = MP_OBJ_SENTINEL;
                        // keep elem->value so that caller can access it if needed
                    }
                    return elem;
                }
            }
            if (MP_LIKELY(lookup_kind != MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)) {
                return NULL;
            }
            // TODO shrink array down over any previously-freed slots
            if (map->used == map->alloc) {
                // TODO: Alloc policy
                map->alloc += 4;
                map->table = m_renew(mp_map_elem_t, map->table, map->used, map->alloc);
                mp_seq_clear(map->table, map->used, map->alloc, sizeof(*map->table));
            }
            mp_map_elem_t *elem = map->table + map->used++;
            elem->key = index;
            if (!MP_OBJ_IS_QSTR(index)) {
                map->all_keys_are_qstrs = 0;
            }
            return elem;
        }
    
        // map is a hash table (not an ordered array), so do a hash lookup
    
        if (map->alloc == 0) {
            if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                mp_map_rehash(map);
            } else {
                return NULL;
            }
        }
    
        // get hash of index, with fast path for common case of qstr
        mp_uint_t hash;
        if (MP_OBJ_IS_QSTR(index)) {
            hash = qstr_hash(MP_OBJ_QSTR_VALUE(index));
        } else {
            hash = MP_OBJ_SMALL_INT_VALUE(mp_unary_op(MP_UNARY_OP_HASH, index));
        }
    
        mp_uint_t pos = hash % map->alloc;
        mp_uint_t start_pos = pos;
        mp_map_elem_t *avail_slot = NULL;
        for (;;) {
            mp_map_elem_t *slot = &map->table[pos];
            if (slot->key == MP_OBJ_NULL) {
                // found NULL slot, so index is not in table
                if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                    map->used += 1;
                    if (avail_slot == NULL) {
                        avail_slot = slot;
                    }
                    avail_slot->key = index;
                    avail_slot->value = MP_OBJ_NULL;
                    if (!MP_OBJ_IS_QSTR(index)) {
                        map->all_keys_are_qstrs = 0;
                    }
                    return avail_slot;
                } else {
                    return NULL;
                }
            } else if (slot->key == MP_OBJ_SENTINEL) {
                // found deleted slot, remember for later
                if (avail_slot == NULL) {
                    avail_slot = slot;
                }
            } else if (slot->key == index || (!compare_only_ptrs && mp_obj_equal(slot->key, index))) {
                // found index
                // Note: CPython does not replace the index; try x={True:'true'};x[1]='one';x
                if (lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
                    // delete element in this slot
                    map->used--;
                    if (map->table[(pos + 1) % map->alloc].key == MP_OBJ_NULL) {
                        // optimisation if next slot is empty
                        slot->key = MP_OBJ_NULL;
                    } else {
                        slot->key = MP_OBJ_SENTINEL;
                    }
                    // keep slot->value so that caller can access it if needed
                }
                return slot;
            }
    
            // not yet found, keep searching in this table
            pos = (pos + 1) % map->alloc;
    
            if (pos == start_pos) {
                // search got back to starting position, so index is not in table
                if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                    if (avail_slot != NULL) {
                        // there was an available slot, so use that
                        map->used++;
                        avail_slot->key = index;
                        avail_slot->value = MP_OBJ_NULL;
                        if (!MP_OBJ_IS_QSTR(index)) {
                            map->all_keys_are_qstrs = 0;
                        }
                        return avail_slot;
                    } else {
                        // not enough room in table, rehash it
                        mp_map_rehash(map);
                        // restart the search for the new element
                        start_pos = pos = hash % map->alloc;
                    }
                } else {
                    return NULL;
                }
            }
        }
    }
    
    /******************************************************************************/
    /* set                                                                        */
    
    #if MICROPY_PY_BUILTINS_SET
    
    void mp_set_init(mp_set_t *set, mp_uint_t n) {
        set->alloc = n;
        set->used = 0;
        set->table = m_new0(mp_obj_t, set->alloc);
    }
    
    STATIC void mp_set_rehash(mp_set_t *set) {
        mp_uint_t old_alloc = set->alloc;
        mp_obj_t *old_table = set->table;
        set->alloc = get_hash_alloc_greater_or_equal_to(set->alloc + 1);
        set->used = 0;
        set->table = m_new0(mp_obj_t, set->alloc);
        for (mp_uint_t i = 0; i < old_alloc; i++) {
            if (old_table[i] != MP_OBJ_NULL && old_table[i] != MP_OBJ_SENTINEL) {
                mp_set_lookup(set, old_table[i], MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
            }
        }
        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) {
        // Note: lookup_kind can be MP_MAP_LOOKUP_ADD_IF_NOT_FOUND_OR_REMOVE_IF_FOUND which
        // is handled by using bitwise operations.
    
        if (set->alloc == 0) {
            if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                mp_set_rehash(set);
            } else {
                return MP_OBJ_NULL;
            }
        }
        mp_uint_t hash = MP_OBJ_SMALL_INT_VALUE(mp_unary_op(MP_UNARY_OP_HASH, index));
        mp_uint_t pos = hash % set->alloc;
        mp_uint_t start_pos = pos;
        mp_obj_t *avail_slot = NULL;
        for (;;) {
            mp_obj_t elem = set->table[pos];
            if (elem == MP_OBJ_NULL) {
                // found NULL slot, so index is not in table
                if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                    if (avail_slot == NULL) {
                        avail_slot = &set->table[pos];
                    }
                    set->used++;
                    *avail_slot = index;
                    return index;
                } else {
                    return MP_OBJ_NULL;
                }
            } else if (elem == MP_OBJ_SENTINEL) {
                // found deleted slot, remember for later
                if (avail_slot == NULL) {
                    avail_slot = &set->table[pos];
                }
            } else if (mp_obj_equal(elem, index)) {
                // found index
                if (lookup_kind & MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
                    // delete element
                    set->used--;
                    if (set->table[(pos + 1) % set->alloc] == MP_OBJ_NULL) {
                        // optimisation if next slot is empty
                        set->table[pos] = MP_OBJ_NULL;
                    } else {
                        set->table[pos] = MP_OBJ_SENTINEL;
                    }
                }
                return elem;
            }
    
            // not yet found, keep searching in this table
            pos = (pos + 1) % set->alloc;
    
            if (pos == start_pos) {
                // search got back to starting position, so index is not in table
                if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
                    if (avail_slot != NULL) {
                        // there was an available slot, so use that
                        set->used++;
                        *avail_slot = index;
                        return index;
                    } else {
                        // not enough room in table, rehash it
                        mp_set_rehash(set);
                        // restart the search for the new element
                        start_pos = pos = hash % set->alloc;
                    }
                } else {
                    return MP_OBJ_NULL;
                }
            }
        }
    }
    
    mp_obj_t mp_set_remove_first(mp_set_t *set) {
        for (mp_uint_t pos = 0; pos < set->alloc; pos++) {
            if (MP_SET_SLOT_IS_FILLED(set, pos)) {
                mp_obj_t elem = set->table[pos];
                // delete element
                set->used--;
                if (set->table[(pos + 1) % set->alloc] == MP_OBJ_NULL) {
                    // optimisation if next slot is empty
                    set->table[pos] = MP_OBJ_NULL;
                } else {
                    set->table[pos] = MP_OBJ_SENTINEL;
                }
                return elem;
            }
        }
        return MP_OBJ_NULL;
    }
    
    void mp_set_clear(mp_set_t *set) {
        m_del(mp_obj_t, set->table, set->alloc);
        set->alloc = 0;
        set->used = 0;
        set->table = NULL;
    }
    
    #endif // MICROPY_PY_BUILTINS_SET
    
    #if defined(DEBUG_PRINT) && DEBUG_PRINT
    void mp_map_dump(mp_map_t *map) {
        for (mp_uint_t i = 0; i < map->alloc; i++) {
            if (map->table[i].key != NULL) {
                mp_obj_print(map->table[i].key, PRINT_REPR);
            } else {
                printf("(nil)");
            }
            printf(": %p\n", map->table[i].value);
        }
        printf("---\n");
    }
    #endif