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/*
* Initially written by Alexey Tourbin <at@altlinux.org>.
*
* The author has dedicated the code to the public domain. Anyone is free
* to copy, modify, publish, use, compile, sell, or distribute the original
* code, either in source code form or as a compiled binary, for any purpose,
* commercial or non-commercial, and by any means.
*/
#define PCRE2_CODE_UNIT_WIDTH 8
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <pcre2.h>
#include <sqlite3ext.h>
SQLITE_EXTENSION_INIT1
typedef struct {
char *pattern_str;
int pattern_len;
pcre2_code *pattern_code;
} cache_entry;
#ifndef CACHE_SIZE
#define CACHE_SIZE 16
#endif
static
void regexp(sqlite3_context *ctx, int argc, sqlite3_value **argv) {
const char *pattern_str, *subject_str;
int pattern_len, subject_len;
pcre2_code *pattern_code;
assert(argc == 2);
/* check null */
if (sqlite3_value_type(argv[0]) == SQLITE_NULL || sqlite3_value_type(argv[1]) == SQLITE_NULL) {
return;
}
pattern_str = (const char *) sqlite3_value_text(argv[0]);
if (!pattern_str) {
sqlite3_result_error(ctx, "no pattern", -1);
return;
}
pattern_len = sqlite3_value_bytes(argv[0]);
subject_str = (const char *) sqlite3_value_text(argv[1]);
if (!subject_str) {
sqlite3_result_error(ctx, "no subject", -1);
return;
}
subject_len = sqlite3_value_bytes(argv[1]);
/* simple LRU cache */
{
int i;
int found = 0;
cache_entry *cache = sqlite3_user_data(ctx);
assert(cache);
for (i = 0; i < CACHE_SIZE && cache[i].pattern_str; i++)
if (
pattern_len == cache[i].pattern_len
&& memcmp(pattern_str, cache[i].pattern_str, pattern_len) == 0
) {
found = 1;
break;
}
if (found) {
if (i > 0) {
cache_entry c = cache[i];
memmove(cache + 1, cache, i * sizeof(cache_entry));
cache[0] = c;
}
} else {
cache_entry c;
const char *err;
int error_code;
PCRE2_SIZE error_position;
c.pattern_code = pcre2_compile(
pattern_str, /* the pattern */
pattern_len, /* the length of the pattern */
0, /* default options */
&error_code, /* for error number */
&error_position, /* for error offset */
NULL); /* use default compile context */
if (!c.pattern_code) {
PCRE2_UCHAR error_buffer[256];
pcre2_get_error_message(error_code, error_buffer, sizeof(error_buffer));
char *e2 = sqlite3_mprintf(
"Cannot compile pattern \"%s\" at offset %d: %s",
pattern_str, (int)error_position, error_buffer);
sqlite3_result_error(ctx, e2, -1);
sqlite3_free(e2);
return;
}
c.pattern_str = malloc(pattern_len);
if (!c.pattern_str) {
sqlite3_result_error(ctx, "malloc: ENOMEM", -1);
pcre2_code_free(c.pattern_code);
return;
}
memcpy(c.pattern_str, pattern_str, pattern_len);
c.pattern_len = pattern_len;
i = CACHE_SIZE - 1;
if (cache[i].pattern_str) {
free(cache[i].pattern_str);
assert(cache[i].pattern_code);
pcre2_code_free(cache[i].pattern_code);
}
memmove(cache + 1, cache, i * sizeof(cache_entry));
cache[0] = c;
}
pattern_code = cache[0].pattern_code;
}
{
int rc;
pcre2_match_data *match_data;
assert(pattern_code);
match_data = pcre2_match_data_create_from_pattern(pattern_code, NULL);
rc = pcre2_match(
pattern_code, /* the compiled pattern */
subject_str, /* the subject string */
subject_len, /* the length of the subject */
0, /* start at offset 0 in the subject */
0, /* default options */
match_data, /* block for storing the result */
NULL); /* use default match context */
assert(rc != 0); // because we have not set match_data
if(rc >= 0) {
// Normal case because we have not set match_data
sqlite3_result_int(ctx, 1);
} else if(rc == PCRE2_ERROR_NOMATCH) {
sqlite3_result_int(ctx, 0);
} else { // (rc < 0 and the code is not one of the above)
PCRE2_UCHAR error_buffer[256];
pcre2_get_error_message(rc, error_buffer, sizeof(error_buffer));
sqlite3_result_error(ctx, error_buffer, -1);
return;
}
pcre2_match_data_free(match_data);
return;
}
}
int sqlite3_extension_init(sqlite3 *db, char **err, const sqlite3_api_routines *api) {
SQLITE_EXTENSION_INIT2(api)
cache_entry *cache = calloc(CACHE_SIZE, sizeof(cache_entry));
if (!cache) {
*err = "calloc: ENOMEM";
return 1;
}
sqlite3_create_function(db, "REGEXP", 2, SQLITE_UTF8, cache, regexp, NULL, NULL);
return 0;
}
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