mirror of
https://github.com/janet-lang/janet
synced 2024-11-15 13:14:48 +00:00
d84cc5342e
Remove caching from strings, tuples, and structs. Keyword style strings removed, now are just symbols. The compiler can decide to treat symbols with a leading ':' differently for mostly the same effect. This was done because as strings are no longer interned, symbols are cheaper to look up and check for equality.
245 lines
8.2 KiB
C
245 lines
8.2 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.
|
|
*/
|
|
|
|
/* The symbol cache is an open hashtable with all active symbols in the program
|
|
* stored in it. As the primary use of symbols is table lookups and equality
|
|
* checks, all symbols are interned so that there is a single copy of it in the
|
|
* whole program. Equality is then just a pointer check. */
|
|
|
|
#include <dst/dst.h>
|
|
|
|
/* Cache state */
|
|
const uint8_t **dst_vm_cache = NULL;
|
|
uint32_t dst_vm_cache_capacity = 0;
|
|
uint32_t dst_vm_cache_count = 0;
|
|
uint32_t dst_vm_cache_deleted = 0;
|
|
|
|
/* Initialize the cache (allocate cache memory) */
|
|
void dst_symcache_init() {
|
|
dst_vm_cache_capacity = 1024;
|
|
dst_vm_cache = calloc(1, dst_vm_cache_capacity * sizeof(const uint8_t **));
|
|
if (NULL == dst_vm_cache) {
|
|
DST_OUT_OF_MEMORY;
|
|
}
|
|
dst_vm_cache_count = 0;
|
|
dst_vm_cache_deleted = 0;
|
|
}
|
|
|
|
/* Deinitialize the cache (free the cache memory) */
|
|
void dst_symcache_deinit() {
|
|
free(dst_vm_cache);
|
|
dst_vm_cache = NULL;
|
|
dst_vm_cache_capacity = 0;
|
|
dst_vm_cache_count = 0;
|
|
dst_vm_cache_deleted = 0;
|
|
}
|
|
|
|
/* Mark an entry in the table as deleted. */
|
|
#define DST_SYMCACHE_DELETED ((NULL) + 1)
|
|
|
|
/* Find an item in the cache and return its location.
|
|
* If the item is not found, return the location
|
|
* where one would put it. */
|
|
static const uint8_t **dst_symcache_findmem(
|
|
const uint8_t *str,
|
|
uint32_t len,
|
|
uint32_t hash,
|
|
int *success) {
|
|
uint32_t bounds[4];
|
|
uint32_t i, j, index;
|
|
const uint8_t **firstEmpty = NULL;
|
|
|
|
/* We will search two ranges - index to the end,
|
|
* and 0 to the index. */
|
|
index = hash % dst_vm_cache_capacity;
|
|
bounds[0] = index;
|
|
bounds[1] = dst_vm_cache_capacity;
|
|
bounds[2] = 0;
|
|
bounds[3] = index;
|
|
for (j = 0; j < 4; j += 2)
|
|
for (i = bounds[j]; i < bounds[j+1]; ++i) {
|
|
const uint8_t *test = dst_vm_cache[i];
|
|
/* Check empty spots */
|
|
if (NULL == test) {
|
|
if (NULL == firstEmpty)
|
|
firstEmpty = dst_vm_cache + i;
|
|
goto notfound;
|
|
}
|
|
/* Check for marked deleted */
|
|
if (DST_SYMCACHE_DELETED == test) {
|
|
if (firstEmpty == NULL)
|
|
firstEmpty = dst_vm_cache + i;
|
|
continue;
|
|
}
|
|
if (dst_string_equalconst(test, str, len, hash)) {
|
|
/* Replace first deleted */
|
|
*success = 1;
|
|
if (firstEmpty != NULL) {
|
|
*firstEmpty = test;
|
|
dst_vm_cache[i] = DST_SYMCACHE_DELETED;
|
|
return firstEmpty;
|
|
}
|
|
return dst_vm_cache + i;
|
|
}
|
|
}
|
|
notfound:
|
|
*success = 0;
|
|
return firstEmpty;
|
|
}
|
|
|
|
#define dst_symcache_find(str, success) \
|
|
dst_symcache_findmem((str), dst_string_length(str), dst_string_hash(str), (success))
|
|
|
|
/* Resize the cache. */
|
|
static void dst_cache_resize(uint32_t newCapacity) {
|
|
uint32_t i, oldCapacity;
|
|
const uint8_t **oldCache = dst_vm_cache;
|
|
const uint8_t **newCache = calloc(1, newCapacity * sizeof(const uint8_t **));
|
|
if (newCache == NULL) {
|
|
DST_OUT_OF_MEMORY;
|
|
}
|
|
oldCapacity = dst_vm_cache_capacity;
|
|
dst_vm_cache = newCache;
|
|
dst_vm_cache_capacity = newCapacity;
|
|
dst_vm_cache_deleted = 0;
|
|
/* Add all of the old cache entries back */
|
|
for (i = 0; i < oldCapacity; ++i) {
|
|
int status;
|
|
const uint8_t **bucket;
|
|
const uint8_t *x = oldCache[i];
|
|
if (x != NULL && x != DST_SYMCACHE_DELETED) {
|
|
bucket = dst_symcache_find(x, &status);
|
|
if (status || bucket == NULL) {
|
|
/* there was a problem with the algorithm. */
|
|
break;
|
|
}
|
|
*bucket = x;
|
|
}
|
|
}
|
|
/* Free the old cache */
|
|
free(oldCache);
|
|
}
|
|
|
|
/* Add an item to the cache */
|
|
static void dst_symcache_put(const uint8_t *x, const uint8_t **bucket) {
|
|
if ((dst_vm_cache_count + dst_vm_cache_deleted) * 2 > dst_vm_cache_capacity) {
|
|
int status;
|
|
dst_cache_resize(dst_vm_cache_count * 4);
|
|
bucket = dst_symcache_find(x, &status);
|
|
}
|
|
/* Add x to the cache */
|
|
dst_vm_cache_count++;
|
|
*bucket = x;
|
|
}
|
|
|
|
/* Remove a symbol from the symcache */
|
|
void dst_symbol_deinit(const uint8_t *sym) {
|
|
int status = 0;
|
|
const uint8_t **bucket = dst_symcache_find(sym, &status);
|
|
if (status) {
|
|
dst_vm_cache_count--;
|
|
dst_vm_cache_deleted++;
|
|
*bucket = DST_SYMCACHE_DELETED;
|
|
}
|
|
}
|
|
|
|
/* Create a symbol from a byte string */
|
|
const uint8_t *dst_symbol(const uint8_t *str, uint32_t len) {
|
|
uint32_t hash = dst_string_calchash(str, len);
|
|
uint8_t *newstr;
|
|
int success = 0;
|
|
const uint8_t **bucket = dst_symcache_findmem(str, len, hash, &success);
|
|
if (success)
|
|
return *bucket;
|
|
newstr = dst_alloc(DST_MEMORY_SYMBOL, 2 * sizeof(uint32_t) + len)
|
|
+ (2 * sizeof(uint32_t));
|
|
dst_string_hash(newstr) = hash;
|
|
dst_string_length(newstr) = len;
|
|
memcpy(newstr, str, len);
|
|
dst_symcache_put((const uint8_t *)newstr, bucket);
|
|
return newstr;
|
|
}
|
|
|
|
/* Get a symbol from a cstring */
|
|
const uint8_t *dst_csymbol(const char *cstr) {
|
|
uint32_t len = 0;
|
|
while (cstr[len]) len++;
|
|
return dst_symbol((const uint8_t *)cstr, len);
|
|
}
|
|
|
|
/* Convert a string to a symbol */
|
|
const uint8_t *dst_symbol_from_string(const uint8_t *str) {
|
|
int success = 0;
|
|
const uint8_t **bucket = dst_symcache_find(str, &success);
|
|
if (success)
|
|
return *bucket;
|
|
dst_symcache_put((const uint8_t *)str, bucket);
|
|
dst_gc_settype(dst_string_raw(str), DST_MEMORY_SYMBOL);
|
|
return str;
|
|
}
|
|
|
|
/* Helper for creating a unique string. Increment an integer
|
|
* represented as an array of integer digits. */
|
|
static void inc_counter(uint8_t *digits, int base, int len) {
|
|
int i;
|
|
uint8_t carry = 1;
|
|
for (i = len - 1; i >= 0; --i) {
|
|
digits[i] += carry;
|
|
carry = 0;
|
|
if (digits[i] == base) {
|
|
digits[i] = 0;
|
|
carry = 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Generate a unique symbol. This is used in the library function gensym. The
|
|
* symbol will be of the format prefix--XXXXXX, where X is a base64 digit, and
|
|
* prefix is the argument passed. */
|
|
const uint8_t *dst_symbol_gen(const uint8_t *buf, uint32_t len) {
|
|
const uint8_t **bucket;
|
|
uint32_t hash;
|
|
uint8_t counter[6] = {63, 63, 63, 63, 63, 63};
|
|
/* Leave spaces for 6 base 64 digits and two dashes. That means 64^6 possible suffixes, which
|
|
* is enough for resolving collisions. */
|
|
uint32_t newlen = len + 8;
|
|
uint32_t newbufsize = newlen + 2 * sizeof(uint32_t);
|
|
uint8_t *str = (uint8_t *)(dst_alloc(DST_MEMORY_SYMBOL, newbufsize) + 2 * sizeof(uint32_t));
|
|
dst_string_length(str) = newlen;
|
|
memcpy(str, buf, len);
|
|
str[len] = '-';
|
|
str[len + 1] = '-';
|
|
uint8_t *saltbuf = str + len + 2;
|
|
int status = 1;
|
|
while (status) {
|
|
int i;
|
|
inc_counter(counter, 64, 6);
|
|
for (i = 0; i < 6; ++i)
|
|
saltbuf[i] = dst_base64[counter[i]];
|
|
hash = dst_string_calchash(str, newlen);
|
|
bucket = dst_symcache_findmem(str, newlen, hash, &status);
|
|
}
|
|
dst_string_hash(str) = hash;
|
|
dst_symcache_put((const uint8_t *)str, bucket);
|
|
return (const uint8_t *)str;
|
|
}
|