Awesome
IOWOW — C11
utility library and persistent key/value storage engine
NOTE: Issues tracker is disabled. You are welcome to contribute, pull requests accepted.
Website https://iowow.softmotions.com
Key components
- utils Useful data structures and various commonly used routines.
- json JSON parsing and manipulation routines incluing JSON Patch/Pointers support.
- iwkv.h Persistent key/value database engine.
- iwfsmfile.h File blocks allocation manager like
malloc()
on files.
Used by
- EJDB2 — Embeddable JSON database engine. http://ejdb.org
- Wirow video conferencing platform
- Pure C Asynchronous HTTP/IO library with websockets, SSL, routing.
IWKV Features
- Support of multiple key-value databases within a single file
- Online database backups
- Native support of integer keys
- Write Ahead Logging (WAL) support
- Ultra-fast traversal of database records
- Compound keys support
- Good performance comparing its main competitors:
lmdb
,leveldb
,kyoto cabinet
- Tiny C11 library (200Kb) can be easily embedded into any software
IWKV Limitations
- Maximum iwkv storage file size:
512 GB (0x7fffffff80)
- Total size of a single key+value record must be not greater than
255Mb (0xfffffff)
Supported platforms
Linux
Building debian packages
mkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DPACKAGE_DEB=ON
make package
RPM based Linux distributions
mkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DPACKAGE_RPM=ON
make package
FreeBSD
Successfully tested on FreeBSD 10/11
OSX
Successfully tested on OSX 10.12/10.13
Windows
MIPS based systems (+big-endian)
Successfully tested on Debian 9.4, MIPS 32, gcc 6.x compiler.
Examples
Store and retrieve records
#include <iowow/iwkv.h>
#include <string.h>
#include <stdlib.h>
int main() {
IWKV_OPTS opts = {
.path = "example1.db",
.oflags = IWKV_TRUNC // Cleanup database before open
};
IWKV iwkv;
IWDB mydb;
iwrc rc = iwkv_open(&opts, &iwkv);
if (rc) {
iwlog_ecode_error3(rc);
return 1;
}
// Now open mydb
// - Database id: 1
rc = iwkv_db(iwkv, 1, 0, &mydb);
if (rc) {
iwlog_ecode_error2(rc, "Failed to open mydb");
return 1;
}
// Work with db: put/get value
IWKV_val key, val;
key.data = "foo";
key.size = strlen(key.data);
val.data = "bar";
val.size = strlen(val.data);
fprintf(stdout, "put: %.*s => %.*s\n",
(int) key.size, (char *) key.data,
(int) val.size, (char *) val.data);
rc = iwkv_put(mydb, &key, &val, 0);
if (rc) {
iwlog_ecode_error3(rc);
return rc;
}
// Retrieve value associated with `foo` key
val.data = 0;
val.size = 0;
rc = iwkv_get(mydb, &key, &val);
if (rc) {
iwlog_ecode_error3(rc);
return rc;
}
fprintf(stdout, "get: %.*s => %.*s\n",
(int) key.size, (char *) key.data,
(int) val.size, (char *) val.data);
iwkv_val_dispose(&val);
iwkv_close(&iwkv);
return 0;
}
Compile and run:
gcc -std=gnu11 -Wall -pedantic -c -o example1.o example1.c
gcc -o example1 example1.o -liowow
./example1
put: foo => bar
get: foo => bar
Cursor iteration example
///
/// Fills database with a set of football table records
/// then traverse records according to club name in ascending and descending orders.
///
#include "iwkv.h"
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
static struct data_s {
const char *club;
uint8_t points;
} _points[] = {
{ "Aston Villa", 25 },
{ "Manchester City", 57 },
{ "Arsenal", 40 },
{ "Everton", 37 },
{ "West Ham United", 27 },
{ "Tottenham Hotspur", 41 },
{ "Wolverhampton Wanderers", 43 },
{ "Norwich City", 21 },
{ "Leicester City", 53 },
{ "Manchester United", 45 },
{ "Newcastle United", 35 },
{ "Brighton & Hove Albion", 29 },
{ "AFC Bournemouth", 27 },
{ "Crystal Palace", 39 },
{ "Sheffield United", 43 },
{ "Burnley", 39 },
{ "Southampton", 34 },
{ "Watford", 27 },
{ "Chelsea", 48 },
{ "Liverpool", 82 },
};
static iwrc run(void) {
IWKV_OPTS opts = {
.path = "cursor1.db",
.oflags = IWKV_TRUNC // Cleanup database before open
};
IWKV iwkv;
IWDB db;
IWKV_cursor cur = 0;
iwrc rc = iwkv_open(&opts, &iwkv);
RCRET(rc);
rc = iwkv_db(iwkv, 1, 0, &db);
RCGO(rc, finish);
for (int i = 0; i < sizeof(_points) / sizeof(_points[0]); ++i) {
struct data_s *n = &_points[i];
IWKV_val key = { .data = (void *) n->club, .size = strlen(n->club) };
IWKV_val val = { .data = &n->points, .size = sizeof(n->points) };
RCC(rc, finish, iwkv_put(db, &key, &val, 0));
}
fprintf(stdout, ">>>> Traverse in descending order\n");
RCC(rc, finish, iwkv_cursor_open(db, &cur, IWKV_CURSOR_BEFORE_FIRST, 0));
while ((rc = iwkv_cursor_to(cur, IWKV_CURSOR_NEXT)) == 0) {
IWKV_val key, val;
RCC(rc, finish, iwkv_cursor_get(cur, &key, &val));
fprintf(stdout, "%.*s: %u\n",
(int) key.size, (char *) key.data,
*(uint8_t *) val.data);
iwkv_kv_dispose(&key, &val);
}
rc = 0;
iwkv_cursor_close(&cur);
fprintf(stdout, "\n>>>> Traverse in ascending order\n");
RCC(rc, finish, iwkv_cursor_open(db, &cur, IWKV_CURSOR_AFTER_LAST, 0));
while ((rc = iwkv_cursor_to(cur, IWKV_CURSOR_PREV)) == 0) {
IWKV_val key, val;
RCC(rc, finish, iwkv_cursor_get(cur, &key, &val));
fprintf(stdout, "%.*s: %u\n",
(int) key.size, (char *) key.data,
*(uint8_t *) val.data);
iwkv_kv_dispose(&key, &val);
}
rc = 0;
iwkv_cursor_close(&cur);
// Select all keys greater or equal than: Manchester United
{
fprintf(stdout, "\n>>>> Records GE: %s\n", _points[9].club);
IWKV_val key = { .data = (void *) _points[9].club, .size = strlen(_points[9].club) }, val;
RCC(rc, finish, iwkv_cursor_open(db, &cur, IWKV_CURSOR_GE, &key));
do {
RCC(rc, finish, iwkv_cursor_get(cur, &key, &val));
fprintf(stdout, "%.*s: %u\n",
(int) key.size, (char *) key.data,
*(uint8_t *) val.data);
iwkv_kv_dispose(&key, &val);
} while ((rc = iwkv_cursor_to(cur, IWKV_CURSOR_NEXT)) == 0);
rc = 0;
}
iwkv_cursor_close(&cur);
finish:
if (cur) {
iwkv_cursor_close(&cur);
}
iwkv_close(&iwkv);
return rc;
}
int main() {
iwrc rc = run();
if (rc) {
iwlog_ecode_error3(rc);
return 1;
}
return 0;
}
Output:
>>>> Traverse in descending order
Wolverhampton Wanderers: 43
West Ham United: 27
Watford: 27
Tottenham Hotspur: 41
Southampton: 34
Sheffield United: 43
Norwich City: 21
Newcastle United: 35
Manchester United: 45
Manchester City: 57
Liverpool: 82
Leicester City: 53
Everton: 37
Crystal Palace: 39
Chelsea: 48
Burnley: 39
Brighton & Hove Albion: 29
Aston Villa: 25
Arsenal: 40
AFC Bournemouth: 27
>>>> Traverse in ascending order
AFC Bournemouth: 27
Arsenal: 40
Aston Villa: 25
Brighton & Hove Albion: 29
Burnley: 39
Chelsea: 48
Crystal Palace: 39
Everton: 37
Leicester City: 53
Liverpool: 82
Manchester City: 57
Manchester United: 45
Newcastle United: 35
Norwich City: 21
Sheffield United: 43
Southampton: 34
Tottenham Hotspur: 41
Watford: 27
West Ham United: 27
Wolverhampton Wanderers: 43
>>>> Records GE: Manchester United
Manchester United: 45
Manchester City: 57
Liverpool: 82
Leicester City: 53
Everton: 37
Crystal Palace: 39
Chelsea: 48
Burnley: 39
Brighton & Hove Albion: 29
Aston Villa: 25
Arsenal: 40
AFC Bournemouth: 27
IWSTART
IWSTART is an automatic CMake initial project generator for C projects based on iowow / iwnet / ejdb2 libs.
https://github.com/Softmotions/iwstart
License
MIT License
Copyright (c) 2012-2024 Softmotions Ltd <info@softmotions.com>
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
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copies of the Software, and to permit persons to whom the Software is
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
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SOFTWARE.