Diff: py/map.c

Revision:

0:5868e8752d44

Child:

2:c89e95946844

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/py/map.c	Sat Apr 16 17:11:56 2016 +0000
@@ -0,0 +1,424 @@
+/*
+ * 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,
+};
+
+// approximatelly doubling primes; made with Mathematica command: Table[Prime[Floor[(1.7)^n]], {n, 3, 24}]
+// prefixed with zero for the empty case.
+STATIC uint32_t 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};
+
+STATIC mp_uint_t get_doubling_prime_greater_or_equal_to(mp_uint_t x) {
+    for (size_t i = 0; i < MP_ARRAY_SIZE(doubling_primes); 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, 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_doubling_prime_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_doubling_prime_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