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YeltsinDB
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Optimize data file constants

master
Yury Kurlykov 2019-12-04 13:46:32 +10:00
parent ab4ea22cc1
commit 3704f944e7
Signed by: t1meshift
GPG Key ID: B133F3167ABF94D8
2 changed files with 64 additions and 44 deletions
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55
inc/YeltsinDB/constants.h
View File

@ -1,6 +1,7 @@
#pragma once
#include <stdint.h>
#include <YeltsinDB/types.h>
/**
* @file constants.h
@ -9,6 +10,56 @@
*/
#define YDB_TABLE_FILE_SIGN "TBL!"
#define YDB_TABLE_PAGE_SIZE 65536
#define YDB_TABLE_FILE_SIGN_SIZE (sizeof(YDB_TABLE_FILE_SIGN))
#define YDB_TABLE_FILE_VER_MAJOR_SIZE (1)
#define YDB_TABLE_FILE_VER_MINOR_SIZE (1)
#define YDB_TABLE_FILE_DATA_START_OFFSET (YDB_TABLE_FILE_SIGN_SIZE + YDB_TABLE_FILE_VER_MAJOR_SIZE + \
YDB_TABLE_FILE_VER_MINOR_SIZE)
#define YDB_TABLE_PAGE_SIZE (65536)
#define YDB_TABLE_PAGE_FLAG_DELETED (1)
#define YDB_TABLE_PAGE_FLAG_DELETED (1)
// TODO static_assert for sizes
// v0
enum YDB_v0_sizes {
YDB_v0_first_page_size = 8,
YDB_v0_last_page_size = 8,
YDB_v0_last_free_page_size = 8,
YDB_v0_page_flags_size = 1,
YDB_v0_page_next_size = 8,
YDB_v0_page_row_count_size = 2,
};
enum YDB_v0_offsets {
YDB_v0_first_page_offset = YDB_TABLE_FILE_DATA_START_OFFSET,
YDB_v0_last_page_offset = YDB_v0_first_page_offset + YDB_v0_first_page_size,
YDB_v0_last_free_page_offset = YDB_v0_last_page_offset + YDB_v0_last_page_size,
YDB_v0_data_offset = YDB_v0_last_free_page_offset + YDB_v0_last_free_page_size,
};
enum YDB_v0_page_offsets {
YDB_v0_page_flags_offset = 0,
YDB_v0_page_next_offset = YDB_v0_page_flags_offset + YDB_v0_page_flags_size,
YDB_v0_page_row_count_offset = YDB_v0_page_next_offset + YDB_v0_page_next_size,
YDB_v0_page_data_offset = YDB_v0_page_row_count_offset + YDB_v0_page_row_count_size,
};
// v1
enum YDB_v1_sizes {
YDB_v1_first_page_size = 8,
YDB_v1_last_page_size = 8,
YDB_v1_last_free_page_size = 8,
YDB_v1_page_flags_size = 1,
YDB_v1_page_next_size = 8,
YDB_v1_page_prev_size = 8,
YDB_v1_page_row_count_size = 2,
};
enum YDB_v1_page_offsets {
YDB_v1_page_flags_offset = 0,
YDB_v1_page_next_offset = YDB_v1_page_flags_offset + YDB_v1_page_flags_size,
YDB_v1_page_prev_offset = YDB_v1_page_next_offset + YDB_v1_page_next_size,
YDB_v1_page_row_count_offset = YDB_v1_page_prev_offset + YDB_v1_page_prev_size,
YDB_v1_page_data_offset = YDB_v1_page_row_count_offset + YDB_v1_page_row_count_size,
};

53
src/ydb.c
View File

@ -33,38 +33,6 @@ struct __YDB_Engine {
FILE *fd; /**< Current table data file descriptor. */
};
struct __data_offsets {
YDB_Offset signature,
ver_major,
ver_minor,
first_page_offset,
last_page_offset,
last_free_page_offset,
meta_end;
};
struct __page_offsets {
YDB_Offset flags,
next_page_offset,
row_count,
meta_end;
};
static const struct __data_offsets v0_offsets = {
.signature = 0,
.ver_major = 4,
.ver_minor = 5,
.first_page_offset = 6,
.last_page_offset = 14,
.last_free_page_offset = 22,
.meta_end = 30
};
static const struct __page_offsets v0_page_offsets = {
.flags = 0,
.next_page_offset = 1,
.row_count = 9,
.meta_end = 11
};
YDB_Engine *ydb_init_instance() {
YDB_Engine *new_instance = calloc(1, sizeof(YDB_Engine));
return new_instance;
@ -98,12 +66,12 @@ static YDB_Error __ydb_read_page(YDB_Engine *inst) {
YDB_Flags page_flags = p_data[0];
YDB_Offset next;
YDB_PageSize row_count;
memcpy(&next, p_data + v0_page_offsets.next_page_offset, sizeof(next));
memcpy(&next, p_data + YDB_v0_page_next_offset, sizeof(next));
REASSIGN_FROM_LE(next);
memcpy(&row_count, p_data + v0_page_offsets.row_count, sizeof(row_count));
memcpy(&row_count, p_data + YDB_v0_page_row_count_offset, sizeof(row_count));
REASSIGN_FROM_LE(row_count);
const YDB_PageSize meta_size = v0_page_offsets.meta_end;
const YDB_PageSize meta_size = YDB_v0_page_data_offset;
const YDB_PageSize data_size = YDB_TABLE_PAGE_SIZE - meta_size;
YDB_TablePage *p = ydb_page_alloc(data_size);
@ -138,12 +106,12 @@ static YDB_Offset __ydb_allocate_page_and_seek(YDB_Engine *inst) {
// TODO throw error on fail
// Write next page offset in the previous page
fseek(inst->fd, inst->last_page_offset + v0_page_offsets.next_page_offset, SEEK_SET); // Skip page flag
fseek(inst->fd, inst->last_page_offset + YDB_v0_page_next_offset, SEEK_SET); // Skip page flag
fwrite(&allocated_page_offset_le, sizeof(YDB_Offset), 1, inst->fd);
// Write last page offset
inst->last_page_offset = result;
fseek(inst->fd, v0_offsets.last_page_offset, SEEK_SET);
fseek(inst->fd, YDB_v0_last_page_offset, SEEK_SET);
fwrite(&allocated_page_offset_le, sizeof(YDB_Offset), 1, inst->fd);
fflush(inst->fd);
} else {
@ -151,10 +119,10 @@ static YDB_Offset __ydb_allocate_page_and_seek(YDB_Engine *inst) {
result = inst->last_free_page_offset;
// Read last free page offset after allocation
fseek(inst->fd, result + v0_page_offsets.next_page_offset, SEEK_SET); // Skip flag
fseek(inst->fd, result + YDB_v0_page_next_offset, SEEK_SET); // Skip flag
fread(&inst->last_free_page_offset, sizeof(YDB_Offset), 1, inst->fd);
REASSIGN_FROM_LE(inst->last_free_page_offset);
fseek(inst->fd, -(long)(sizeof(YDB_Offset) + 1), SEEK_CUR);
fseek(inst->fd, -(long)(sizeof(YDB_Offset) + 1), SEEK_CUR); //FIXME magic
// Rewrite page header
char page_header[] = "\x00" // No flags
@ -163,7 +131,7 @@ static YDB_Offset __ydb_allocate_page_and_seek(YDB_Engine *inst) {
fwrite(page_header, sizeof(page_header)-1, 1, inst->fd);
// Write last free page offset after allocation in file
fseek(inst->fd, v0_offsets.last_free_page_offset, SEEK_SET);
fseek(inst->fd, YDB_v0_last_free_page_offset, SEEK_SET);
YDB_Offset lfp_offset_le = TO_LE(inst->last_free_page_offset);
fwrite(&lfp_offset_le, sizeof(YDB_Offset), 1, inst->fd);
}
@ -184,6 +152,7 @@ YDB_Error ydb_load_table(YDB_Engine *instance, const char *path) {
instance->fd = fopen(path, "rb+");
THROW_IF_NULL(instance->fd, YDB_ERR_UNKNOWN); // TODO file open error
// FIXME magic
char signature[4];
fread(signature, 1, 4, instance->fd);
int signature_match = memcmp(signature, YDB_TABLE_FILE_SIGN, 3) == 0;
@ -350,7 +319,7 @@ YDB_Error ydb_append_page(YDB_Engine* instance, YDB_TablePage* page) {
YDB_PageSize rc = ydb_page_row_count_get(page);
YDB_Flags f = ydb_page_flags_get(page);
YDB_Offset next = 0;
char d[YDB_TABLE_PAGE_SIZE - v0_page_offsets.meta_end];
char d[YDB_TABLE_PAGE_SIZE - YDB_v0_page_data_offset];
ydb_page_data_seek(page, 0);
if (ydb_page_data_read(page, d, sizeof(d))) {
return YDB_ERR_UNKNOWN; // FIXME
@ -395,7 +364,7 @@ YDB_Error ydb_replace_current_page(YDB_Engine *instance, YDB_TablePage *page) {
fwrite(&row_cnt_le, sizeof(row_cnt), 1, instance->fd);
// Write data
char page_data[YDB_TABLE_PAGE_SIZE - v0_page_offsets.meta_end];
char page_data[YDB_TABLE_PAGE_SIZE - YDB_v0_page_data_offset];
ydb_page_data_seek(page, 0);
if (ydb_page_data_read(page, page_data, sizeof(page_data))) {
return YDB_ERR_UNKNOWN; // FIXME