todo_record.c

uclinux 下写的一个 todo 程序

/*
 *  Copyright (C) 2000 EmSoft Limited (www.emsoftltd.com)
 *
 *  <Description of the file>
 *
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "todo_record.h"

#define setLength(sum, array, size) \
    array = size; \
    sum += array;

#define memcpy_with_offset(desc, src, size, ptr) \
    memcpy(desc, src, size); \
    ptr += size;

#define memcpy_offset_desc(desc, src, size) memcpy_with_offset(desc, src, size, desc)
#define memcpy_offset_src(desc, src, size) memcpy_with_offset(desc, src, size, src)

static int memopad_record_size(Todo *todo, int *fieldSizes) {
    int sum = 0;
    
    setLength(sum, fieldSizes[0], sizeof(int));
    setLength(sum, fieldSizes[1], sizeof(short));
    setLength(sum, fieldSizes[2], sizeof(gboolean));
    setLength(sum, fieldSizes[3], sizeof(long));
    setLength(sum, fieldSizes[4], strlen(todo->title) + 1);
    
    return sum + sizeof(int) * NUM_OF_FIELDS + 1;
}

static int serialize(Todo *todo, char**raw_data) {
    int length;
    int sizes[NUM_OF_FIELDS];
    char *ptr;
    
    length = memopad_record_size(todo, sizes);
    
    *raw_data = g_new0(char, length);
    ptr = *raw_data;
    
    memcpy_offset_desc(ptr, sizes,                  sizeof(int) * NUM_OF_FIELDS);
    memcpy_offset_desc(ptr, &(todo->todo_id),       sizes[0]);
    memcpy_offset_desc(ptr, &(todo->priority),      sizes[1]);
    memcpy_offset_desc(ptr, &(todo->completed),     sizes[2]);
    memcpy_offset_desc(ptr, &(todo->dueDate),       sizes[3]);
    memcpy_offset_desc(ptr, todo->title,            sizes[4]);
    
    return length;
}

void deserialize(Todo **todo, char *raw_data) {
    int sizes[NUM_OF_FIELDS];
    char *ptr;
    
    ptr = raw_data;
    *todo = g_new0(Todo, 1);
    
    memcpy_offset_src(sizes, ptr, sizeof(int) * NUM_OF_FIELDS);
    
    (*todo)->title = g_new0(char, sizes[4]);
    
    memcpy_offset_src(&((*todo)->todo_id),      ptr, sizes[0]);
    memcpy_offset_src(&((*todo)->priority),     ptr, sizes[1]);
    memcpy_offset_src(&((*todo)->completed),    ptr, sizes[2]);
    memcpy_offset_src(&((*todo)->dueDate),      ptr, sizes[3]);
    memcpy_offset_src((*todo)->title,           ptr, sizes[4]);
}

int todo_record_db_open() {
    int context;
    //char *filename;
    //char *path;
    
    /*
    path = getenv("DATABASE_PATH");
    
    if (path != NULL) {
        filename = g_strconcat(path, "/", TODO_DATABASE, NULL);
    } else {
        filename = g_strdup(TODO_DATABASE);
    }*/
    
    //printf("%s: database file = %s\n", __FUNCTION__, filename);
    context = db_open(TODO_DATABASE, DB_WRITER | DB_CREATE_IF_NOT_EXIST);
    
    //g_free(filename);
    return context;
}

void todo_record_db_close(int context) {
    db_close(context);
}

void todo_record_close(int context, Todo *todo) {
    if (todo->dirty)
        todo_record_save(context, todo);
    
    g_free(todo);
}

Todo *todo_record_new() {
    Todo *todo;
    todo = g_new0(Todo, 1);
    todo->new = TRUE;
    return todo;
}

Todo *todo_record_load (int context, int key) {
    Todo *todo;
    char *raw_data;
    
    raw_data = db_fetch(context, key);
    
    g_return_val_if_fail(raw_data != NULL, NULL);
    
    deserialize(&todo, raw_data);
    
    todo->new   = FALSE;
    todo->dirty = FALSE;
    
    free(raw_data);
    
    return todo;
}

int todo_record_save(int context, Todo *todo) {
    char *raw_data;
    int record_length = 0, result;
    
    if (todo->new)
        todo->todo_id = db_getNextKey(context);
    
    record_length = serialize(todo, &raw_data);
    
    result = db_store(context, raw_data, record_length, !(todo->new), &(todo->todo_id));
    
    if (result == 0) {
        todo->dirty = FALSE;
        todo->new = FALSE;
    }
    
    free(raw_data);
    
    return result;
}

int todo_record_delete(int context, Todo *todo) {
    int result;
    
    g_return_val_if_fail(todo != NULL, -1);
    
    result = db_delete(context, todo->todo_id);
    
    return result;
}