Initial import.

This commit is contained in:
Kyle Isom 2023-10-06 03:13:46 +00:00
commit 8b8be9421a
11 changed files with 735 additions and 0 deletions

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.gitignore vendored Normal file
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*.a
*.o
*.bin
build
cmake-build-*
tlv_test

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Arena.cc Normal file
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if defined(__linux__)
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#endif
#include "Arena.h"
#define ARENA_UNINIT 0
#define ARENA_STATIC 1
#define ARENA_ALLOC 2
#define ARENA_MMAP 3
#define PROT_RW PROT_READ|PROT_WRITE
int
new_arena(Arena &arena, uint8_t *mem, size_t size)
{
arena.store = mem;
arena.size = size;
arena.type = ARENA_STATIC;
return 0;
}
int
alloc_new_arena(Arena &arena, size_t size)
{
if (arena.size > 0) {
if (arena_destroy(arena) != 0) {
return -1;
}
}
arena.type = ARENA_ALLOC;
arena.size = size;
arena.store = (uint8_t *)calloc(sizeof(uint8_t), size);
if (arena.store == NULL) {
return -1;
}
return 0;
}
#if defined(__linux__)
int
mmap_arena(Arena &arena, int fd, size_t size)
{
if (arena.size > 0) {
if (arena_destroy(arena) != 0) {
return -1;
}
}
arena.type = ARENA_MMAP;
arena.size = size;
arena.store = (uint8_t *)mmap(NULL, size, PROT_RW, MAP_SHARED, fd, 0);
if ((void *)arena.store == MAP_FAILED) {
return -1;
}
arena.fd = fd;
return 0;
}
int
open_arena(Arena &arena, const char *path)
{
struct stat st;
if (arena.size > 0) {
if (arena_destroy(arena) != 0) {
return -1;
}
}
if (stat(path, &st) != 0) {
return -1;
}
arena.fd = open(path, O_RDWR);
if (arena.fd == -1) {
return -1;
}
return mmap_arena(arena, arena.fd, (size_t)st.st_size);
}
int
create_arena(Arena &arena, const char *path, size_t size, mode_t mode)
{
int fd = 0;
if (arena.size > 0) {
if (arena_destroy(arena) != 0) {
return -1;
}
}
fd = open(path, O_WRONLY|O_CREAT, mode);
if (fd == -1) {
return -1;
}
if (ftruncate(fd, size) == -1) {
return -1;
}
close(fd);
return open_arena(arena, path);
}
#endif
void
arena_clear(Arena &arena)
{
if (arena.size == 0) {
return;
}
memset(arena.store, 0, arena.size);
}
int
arena_destroy(Arena &arena)
{
if (arena.type == ARENA_UNINIT) {
return 0;
}
switch (arena.type) {
case ARENA_STATIC:
break;
case ARENA_ALLOC:
free(arena.store);
break;
case ARENA_MMAP:
if (munmap(arena.store, arena.size) == -1) {
return -1;
}
if (close(arena.fd) == -1) {
return -1;
}
arena.fd = 0;
break;
default:
abort();
return -1;
}
arena.type = ARENA_UNINIT;
arena.size = 0;
arena.store = NULL;
return 0;
}
int
write_arena(Arena &arena, const char *path)
{
FILE *arenaFile = NULL;
int retc = -1;
arenaFile = fopen(path, "w");
if (arenaFile == NULL) {
return -1;
}
if (fwrite(arena.store, sizeof(*arena.store), arena.size,
arenaFile) == arena.size) {
retc = 0;
}
if (fclose(arenaFile) != 0) {
return -1;
}
return retc;
}

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#ifndef KIMODEM_ARENA_H
#define KIMODEM_ARENA_H
#include <sys/stat.h>
#include <cstddef>
#include <cstdint>
typedef struct {
uint8_t *store;
size_t size;
int fd;
uint8_t type;
} Arena;
int new_arena(Arena &, uint8_t *, size_t);
int alloc_new_arena(Arena &, size_t);
#if defined(__linux__)
int mmap_arena(Arena &, int); /* arena will own fd */
int create_arena(Arena &arena, const char *path, size_t size, mode_t mode);
int open_arena(Arena &, const char *, size_t);
#endif
void arena_clear(Arena &);
int arena_destroy(Arena &); /* dispose of any memory used by arena */
/* DANGER: if arena is file backed (mmap or open), DO NOT WRITE TO THE
* BACKING FILE! */
int write_arena(const char *);
#endif

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CMakeLists.txt Normal file
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cmake_minimum_required(VERSION 3.25)
project(klib CXX)
set(CMAKE_CXX_STANDARD 14)
add_library(klib STATIC
Arena.cc
TLV.cc)
add_executable(tlv_test tlv_test.cc)
target_link_libraries(tlv_test klib)

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TARGET := klib.a
TESTS := tlv_test
HEADERS := $(wildcard *.h)
SOURCES := $(wildcard *.cc)
OBJS := Arena.o Phonebook.o TLV.o
CXX := clang++
CXXFLAGS := -g -std=c++14 -Werror -Wall
.PHONY: all
all: $(TARGET) $(TESTS) tags run-tests
tags: $(HEADERS) $(SOURCES)
ctags $(HEADERS) $(SOURCES)
$(TARGET): $(OBJS)
$(AR) rcs $@ $(OBJS)
tlv_test: tlv_test.o $(TARGET)
$(CXX) -o $@ $(CXXFLAGS) $@.o $(TARGET)
.PHONY: print-%
print-%: ; @echo '$(subst ','\'',$*=$($*))'
klib.a: $(OBJS)
%.o: %.cc
$(CXX) -o $@ -c $(CXXFLAGS) $<
.PHONY: clean
clean:
# build outputs
rm -f $(TARGET) $(TESTS) *.o
# test miscellaneous
rm -f core core.* tags arena_test.bin
.PHONY: run-tests
run-tests: $(TESTS)
for testbin in $(TESTS); \
do \
echo "./$${testbin}" ; \
./$${testbin}; \
done

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Phonebook.cc Normal file
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#include <cstring>
#include <cstdlib>
#include "Phonebook.h"
bool
Phonebook::lookup(const char *key, uint8_t klen, TLV::Record &res)
{
res.Tag = this->ktag;
uint8_t *cursor = TLV::find_tag(this->arena, NULL, res);
while (cursor != NULL) {
if ((klen == res.Len) &&
(memcmp(res.Val, key, klen) == 0)) {
TLV::read_from_memory(res, cursor);
if (res.Tag != this->vtag) {
abort();
}
return true;
}
cursor = TLV::find_tag(this->arena, cursor, res);
}
return false;
}
int
Phonebook::set(const char *key, uint8_t klen, char *val, uint8_t vlen)
{
TLV::Record rec;
uint8_t *cursor = NULL;
set_record(rec, this->ktag, klen, key);
cursor = this->seek(key, klen);
if (cursor != NULL) {
TLV::delete_record(this->arena, cursor);
TLV::delete_record(this->arena, cursor);
}
cursor = TLV::write_to_memory(this->arena, NULL, rec);
if (cursor == NULL) {
return -1;
}
set_record(rec, this->vtag, vlen, val);
if (TLV::write_to_memory(this->arena, NULL, rec) == NULL) {
return -1;
}
return 0;
}
uint8_t *
Phonebook::seek(const char *key, uint8_t klen)
{
TLV::Record rec;
rec.Tag = this->ktag;
uint8_t *cursor = TLV::find_tag(this->arena, NULL, rec);
while (cursor != NULL) {
if ((klen == rec.Len) &&
(memcmp(rec.Val, key, klen) == 0)) {
return cursor;
}
cursor = TLV::skip_record(rec, cursor);
}
return NULL;
}
bool
Phonebook::has(const char *key, uint8_t klen)
{
return this->seek(key, klen) != NULL;
}

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#ifndef KLIB_PHONEBOOK_H
#define KLIB_PHONEBOOK_H
#include "Arena.h"
#include "TLV.h"
#define PHONEBOOK_KEY_TAG 1
#define PHONEBOOK_VAL_TAG 2
class Phonebook {
public:
Phonebook(Arena &arena) :
arena(arena),
ktag(PHONEBOOK_KEY_TAG),
vtag(PHONEBOOK_VAL_TAG) {} ;
Phonebook(Arena &arena, uint8_t kt, uint8_t vt) :
arena(arena),
ktag(kt),
vtag(vt) {};
bool lookup(const char *key, uint8_t klen, TLV::Record &res);
int set(const char *key, uint8_t klen, char *val, uint8_t vlen);
bool has(const char *key, uint8_t klen);
private:
uint8_t *seek(const char *key, uint8_t klen);
Arena &arena;
uint8_t ktag;
uint8_t vtag;
};
#endif

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#include <cstring>
#include "TLV.h"
#define REC_SIZE(x) ((std::size_t)x.Len + 2)
namespace TLV {
static bool
space_available(Arena &arena, uint8_t *cursor, uint8_t len)
{
uintptr_t remaining = 0;
if (cursor == NULL) {
return false;
}
remaining = (uintptr_t)cursor - (uintptr_t)arena.store;
remaining = arena.size - remaining;
return ((size_t)remaining >= ((size_t)len+2));
}
uint8_t *
write_to_memory(Arena &arena, uint8_t *cursor, Record &rec)
{
// If cursor is NULL, the user needs us to select an empty
// slot for the record. If we can't find one, that's an
// error.
//
// If, however, the user gives us a cursor, we'll trust it
// (though space_available will sanity check that cursor).
if (cursor == NULL) {
cursor = find_empty(arena, cursor);
if (cursor == NULL) {
return NULL;
}
}
if (!space_available(arena, cursor, rec.Len)) {
return NULL;
}
memcpy(cursor, &rec, REC_SIZE(rec));
cursor = skip_record(rec, cursor);
return cursor;
}
void
set_record(Record &rec, uint8_t tag, uint8_t len, const char *val)
{
rec.Tag = tag;
rec.Len = len;
memcpy(rec.Val, val, len);
}
void
read_from_memory(Record &rec, uint8_t *cursor)
{
rec.Tag = cursor[0];
rec.Len = cursor[1];
memcpy(rec.Val, cursor+2, rec.Len);
}
/*
* returns a pointer to memory where the record was found,
* e.g. find_tag(...)[0] is the tag of the found record.
*/
uint8_t *
find_tag(Arena &arena, uint8_t *cursor, Record &rec)
{
uint8_t tag, len;
if (cursor == NULL) {
cursor = arena.store;
}
while ((tag = cursor[0]) != rec.Tag) {
len = cursor[1];
if (!space_available(arena, cursor, len)) {
return NULL;
}
cursor += len;
cursor += 2;
}
if (tag != rec.Tag) {
return NULL;
}
if (tag != TAG_EMPTY) {
read_from_memory(rec, cursor);
cursor = skip_record(rec, cursor);
}
return cursor;
}
uint8_t *
find_empty(Arena &arena, uint8_t *cursor) {
Record rec;
rec.Tag = TAG_EMPTY;
return find_tag(arena, cursor, rec);
}
uint8_t *
skip_record(Record &rec, uint8_t *cursor)
{
return (uint8_t *)((uintptr_t)cursor + rec.Len + 2);
}
void
delete_record(Arena &arena, uint8_t *cursor)
{
//
if (cursor == NULL) {
return;
}
uintptr_t len = cursor[1] + 2;
uintptr_t stop = (uintptr_t)arena.size - (uintptr_t)cursor;
stop -= len;
for (uintptr_t i = (uintptr_t)cursor; i < stop; i++) {
cursor[i] = cursor[i+len];
};
}
} // namespace TLV

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#ifndef KIMODEM_TLV_H
#define KIMODEM_TLV_H
#include <cstdint>
#include "Arena.h"
#ifndef TLV_MAX_LEN
#define TLV_MAX_LEN 253
#endif
#define TAG_EMPTY 0
namespace TLV {
struct Record {
uint8_t Tag;
uint8_t Len;
char Val[TLV_MAX_LEN];
};
uint8_t *write_to_memory(Arena &, uint8_t *, Record &);
void read_from_memory(Record &, uint8_t *);
void set_record(Record &, uint8_t, uint8_t, const char *);
void delete_record(Arena &, uint8_t *);
/*
* returns a pointer to memory where the record was found,
* e.g. find_tag(...)[0] is the tag of the found record.
*/
uint8_t *find_tag(Arena &, uint8_t *, Record &);
uint8_t *find_empty(Arena &, uint8_t *);
uint8_t *skip_record(Record &, uint8_t *);
} // namespace TLV
#endif

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#ifndef KLIB_TEST_FIXTURES_H
#define KLIB_TEST_FIXTURES_H
#define ARENA_SIZE 128
#define ARENA_FILE "arena_test.bin"
/* strlen=13 */
#define TEST_STR1 "Hello, world"
#define TEST_STRLEN1 13
#define TEST_STR2 "Bye, world!!"
#define TEST_STRLEN2 13
#define TEST_STR3 "Hello, arena"
#define TEST_STRLEN3 13
/* strlen 35 */
#define TEST_STR4 "How is a raven like a writing desk?"
#define TEST_STRLEN4 35
#endif

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#include <cassert>
#include <cstring>
#include <iostream>
#include "Arena.h"
#include "TLV.h"
#include "test_fixtures.h"
static uint8_t arena_buffer[ARENA_SIZE];
static bool
cmp_record(TLV::Record &a, TLV::Record &b)
{
if (a.Tag != b .Tag) {
return false;
}
if (a.Len != b.Len) {
return false;
}
if (memcmp(a.Val, b.Val, a.Len) != 0) {
return false;
}
return true;
}
bool
tlv_test_suite(Arena &backend)
{
TLV::Record rec1, rec2, rec3, rec4;
uint8_t *cursor = NULL;
TLV::set_record(rec1, 1, TEST_STRLEN1, TEST_STR1);
TLV::set_record(rec2, 2, TEST_STRLEN2, TEST_STR2);
TLV::set_record(rec3, 1, TEST_STRLEN4, TEST_STR4);
rec4.Tag = 1;
assert(TLV::write_to_memory(backend, cursor, rec1) != NULL);
assert((cursor = TLV::write_to_memory(backend, cursor, rec2)) != NULL);
assert(TLV::write_to_memory(backend, cursor, rec3) != NULL);
cursor = NULL;
// the cursor should point at the next record,
// and rec4 should contain the same data as rec1.
cursor = TLV::find_tag(backend, cursor, rec4);
assert(cursor != NULL);
assert(cursor != backend.store);
assert(cmp_record(rec1, rec4));
cursor = TLV::find_tag(backend, cursor, rec4);
assert(cursor != NULL);
assert(cmp_record(rec3, rec4));
TLV::set_record(rec4, 3, TEST_STRLEN3, TEST_STR3);
assert(TLV::write_to_memory(backend, NULL, rec4));
TLV::delete_record(backend, cursor);
assert(cursor[0] == TAG_EMPTY);
return true;
}
bool
run_suite(Arena &backend, const char *label)
{
std::cout << "running test suite " << label << ": ";
if (!tlv_test_suite(backend)) {
std::cout << "FAILED" << std::endl;
return false;
}
std::cout << "OK" << std::endl;
std::cout << "\tdestroying arena: ";
if (arena_destroy(backend) != 0) {
std::cout << "FAILED" << std::endl;
return false;
}
std::cout << "OK" << std::endl;
return true;
}
int
main(int argc, const char *argv[])
{
Arena arena_static;
Arena arena_mem;
Arena arena_file;
std::cout << "TESTPROG: " << argv[0] << std::endl;
if (-1 == new_arena(arena_static, arena_buffer, ARENA_SIZE)) {
abort();
} else if (!run_suite(arena_static, "arena_static")) {
abort();
}
if (-1 == create_arena(arena_file, ARENA_FILE, ARENA_SIZE, 0644)) {
abort();
} else if (!run_suite(arena_file, "arena_file")) {
abort();
}
if (-1 == alloc_new_arena(arena_mem, ARENA_SIZE)) {
abort();
} else if (!run_suite(arena_mem, "arena_mem")) {
abort();
}
std::cout << "OK" << std::endl;
return 0;
}