mirror of
https://github.com/janet-lang/janet
synced 2024-11-19 07:04:48 +00:00
239 lines
8.3 KiB
C
239 lines
8.3 KiB
C
/*
|
|
* Copyright (c) 2017 Calvin Rose
|
|
*
|
|
* 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 <dst/dst.h>
|
|
#include "gc.h"
|
|
#include "util.h"
|
|
|
|
#define dst_struct_maphash(cap, hash) ((uint32_t)(hash & (cap - 1)));
|
|
|
|
/* Begin creation of a struct */
|
|
DstKV *dst_struct_begin(int32_t count) {
|
|
|
|
/* Calculate capacity as power of 2 after 2 * count. */
|
|
int32_t capacity = dst_tablen(2 * count);
|
|
if (capacity < 0) capacity = dst_tablen(count);
|
|
|
|
size_t s = sizeof(int32_t) * 4 + (capacity * sizeof(DstKV));
|
|
char *data = dst_gcalloc(DST_MEMORY_STRUCT, s);
|
|
DstKV *st = (DstKV *) (data + 4 * sizeof(int32_t));
|
|
dst_memempty(st, capacity);
|
|
dst_struct_length(st) = count;
|
|
dst_struct_capacity(st) = capacity;
|
|
dst_struct_hash(st) = 0;
|
|
return st;
|
|
}
|
|
|
|
/* Find an item in a struct */
|
|
const DstKV *dst_struct_find(const DstKV *st, Dst key) {
|
|
int32_t cap = dst_struct_capacity(st);
|
|
int32_t index = dst_struct_maphash(cap, dst_hash(key));
|
|
int32_t i;
|
|
for (i = index; i < cap; i++)
|
|
if (dst_checktype(st[i].key, DST_NIL) || dst_equals(st[i].key, key))
|
|
return st + i;
|
|
for (i = 0; i < index; i++)
|
|
if (dst_checktype(st[i].key, DST_NIL) || dst_equals(st[i].key, key))
|
|
return st + i;
|
|
return NULL;
|
|
}
|
|
|
|
/* Put a kv pair into a struct that has not yet been fully constructed.
|
|
* Nil keys and values are ignored, extra keys are ignore, and duplicate keys are
|
|
* ignored.
|
|
*
|
|
* Much of this complexity is in the robinhood hashing scheme, an
|
|
* attempt to make structs that are created with arguments in a different
|
|
* order to have the same internal representation. If this turns out to be
|
|
* incorrect or too complicated, another scheme that would definitely work
|
|
* is inserting all keys in sorted order with any deterministic hashing scheme. */
|
|
void dst_struct_put(DstKV *st, Dst key, Dst value) {
|
|
int32_t cap = dst_struct_capacity(st);
|
|
int32_t hash = dst_hash(key);
|
|
int32_t index = dst_struct_maphash(cap, hash);
|
|
int32_t i, j, dist;
|
|
int32_t bounds[4] = {index, cap, 0, index};
|
|
if (dst_checktype(key, DST_NIL) || dst_checktype(value, DST_NIL)) return;
|
|
/* Avoid extra items */
|
|
if (dst_struct_hash(st) == dst_struct_length(st)) return;
|
|
for (dist = 0, j = 0; j < 4; j += 2)
|
|
for (i = bounds[j]; i < bounds[j + 1]; i++, dist++) {
|
|
int status;
|
|
int32_t otherhash;
|
|
int32_t otherindex, otherdist;
|
|
DstKV *kv = st + i;
|
|
/* We found an empty slot, so just add key and value */
|
|
if (dst_checktype(kv->key, DST_NIL)) {
|
|
kv->key = key;
|
|
kv->value = value;
|
|
/* Update the temporary count */
|
|
dst_struct_hash(st)++;
|
|
return;
|
|
}
|
|
/* Robinhood hashing - check if colliding kv pair
|
|
* is closer to their source than current. We use robinhood
|
|
* hashing to ensure that equivalent structs that are contsructed
|
|
* with different order have the same internal layout, and therefor
|
|
* will compare properly - i.e., {1 2 3 4} should equal {3 4 1 2}. */
|
|
otherhash = dst_hash(kv->key);
|
|
otherindex = dst_struct_maphash(cap, otherhash);
|
|
otherdist = (i + cap - otherindex) & (cap - 1);
|
|
if (dist < otherdist)
|
|
status = -1;
|
|
else if (otherdist < dist)
|
|
status = 1;
|
|
else if (hash < otherhash)
|
|
status = -1;
|
|
else if (otherhash < hash)
|
|
status = 1;
|
|
else
|
|
status = dst_compare(key, kv->key);
|
|
/* If other is closer to their ideal slot */
|
|
if (status == 1) {
|
|
/* Swap current kv pair with pair in slot */
|
|
DstKV temp = *kv;
|
|
kv->key = key;
|
|
kv->value = value;
|
|
key = temp.key;
|
|
value = temp.value;
|
|
/* Save dist and hash of new kv pair */
|
|
dist = otherdist;
|
|
hash = otherhash;
|
|
} else if (status == 0) {
|
|
/* This should not happen - it means
|
|
* than a key was added to the struct more than once */
|
|
dst_exit("struct double put fail");
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Finish building a struct */
|
|
const DstKV *dst_struct_end(DstKV *st) {
|
|
if (dst_struct_hash(st) != dst_struct_length(st)) {
|
|
/* Error building struct, probably duplicate values. We need to rebuild
|
|
* the struct using only the values that went in. The second creation should always
|
|
* succeed. */
|
|
int32_t i, realCount;
|
|
DstKV *newst;
|
|
realCount = 0;
|
|
for (i = 0; i < dst_struct_capacity(st); i++) {
|
|
DstKV *kv = st + i;
|
|
realCount += dst_checktype(kv->key, DST_NIL) ? 1 : 0;
|
|
}
|
|
newst = dst_struct_begin(realCount);
|
|
for (i = 0; i < dst_struct_capacity(st); i++) {
|
|
DstKV *kv = st + i;
|
|
if (!dst_checktype(kv->key, DST_NIL)) {
|
|
dst_struct_put(newst, kv->key, kv->value);
|
|
}
|
|
}
|
|
st = newst;
|
|
}
|
|
dst_struct_hash(st) = dst_kv_calchash(st, dst_struct_capacity(st));
|
|
return (const DstKV *)st;
|
|
}
|
|
|
|
/* Get an item from a struct */
|
|
Dst dst_struct_get(const DstKV *st, Dst key) {
|
|
const DstKV *kv = dst_struct_find(st, key);
|
|
if (NULL == kv || dst_checktype(kv->key, DST_NIL)) {
|
|
return dst_wrap_nil();
|
|
} else {
|
|
return kv->value;
|
|
}
|
|
}
|
|
|
|
/* Get the next key in a struct */
|
|
const DstKV *dst_struct_next(const DstKV *st, const DstKV *kv) {
|
|
const DstKV *end = st + dst_struct_capacity(st);
|
|
kv = (kv == NULL) ? st : kv + 1;
|
|
while (kv < end) {
|
|
if (!dst_checktype(kv->key, DST_NIL)) return kv;
|
|
kv++;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/* Convert struct to table */
|
|
DstTable *dst_struct_to_table(const DstKV *st) {
|
|
DstTable *table = dst_table(dst_struct_capacity(st));
|
|
int32_t i;
|
|
for (i = 0; i < dst_struct_capacity(st); i++) {
|
|
const DstKV *kv = st + i;
|
|
if (!dst_checktype(kv->key, DST_NIL)) {
|
|
dst_table_put(table, kv->key, kv->value);
|
|
}
|
|
}
|
|
return table;
|
|
}
|
|
|
|
/* Check if two structs are equal */
|
|
int dst_struct_equal(const DstKV *lhs, const DstKV *rhs) {
|
|
int32_t index;
|
|
int32_t llen = dst_struct_capacity(lhs);
|
|
int32_t rlen = dst_struct_capacity(rhs);
|
|
int32_t lhash = dst_struct_hash(lhs);
|
|
int32_t rhash = dst_struct_hash(rhs);
|
|
if (llen != rlen)
|
|
return 0;
|
|
if (lhash != rhash)
|
|
return 0;
|
|
for (index = 0; index < llen; index++) {
|
|
const DstKV *l = lhs + index;
|
|
const DstKV *r = rhs + index;
|
|
if (!dst_equals(l->key, r->key))
|
|
return 0;
|
|
if (!dst_equals(l->value, r->value))
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/* Compare structs */
|
|
int dst_struct_compare(const DstKV *lhs, const DstKV *rhs) {
|
|
int32_t i;
|
|
int32_t lhash = dst_struct_hash(lhs);
|
|
int32_t rhash = dst_struct_hash(rhs);
|
|
int32_t llen = dst_struct_capacity(lhs);
|
|
int32_t rlen = dst_struct_capacity(rhs);
|
|
if (llen < rlen)
|
|
return -1;
|
|
if (llen > rlen)
|
|
return 1;
|
|
if (lhash < rhash)
|
|
return -1;
|
|
if (lhash > rhash)
|
|
return 1;
|
|
for (i = 0; i < llen; ++i) {
|
|
const DstKV *l = lhs + i;
|
|
const DstKV *r = rhs + i;
|
|
int comp = dst_compare(l->key, r->key);
|
|
if (comp != 0) return comp;
|
|
comp = dst_compare(l->value, r->value);
|
|
if (comp != 0) return comp;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#undef dst_struct_maphash
|