myosfile_win32.c

sourceforge历史版本完整下载: http://sourceforge.net/project/showfiles.php?group_id=202044 提供了基于b树索引算法的文件数据数据

/**
 * @file myOsFile.c 封装不同系统的文件操作接口 2008-1-31 00:43
 *
 * @author lin shao chuan (email:[e-mail], msn:[e-mail])
 *
 * @brief if it works, it was written by lin shao chuan, if not, i don't know who wrote it.
 *        封装不同系统的文件操作接口
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  lin shao chuan makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 * see the GNU General Public License  for more detail.
 */
#include "myOsFile.h"

#include <assert.h>
#include <windows.h>

#ifndef INVALID_SET_FILE_POINTER
#define INVALID_SET_FILE_POINTER -1
#endif


typedef struct __os_file_t_
{
	/* 文件句柄 */
	HANDLE hfile;

	/* 内存池句柄 */
	HMYMEMPOOL hm;
}os_file_t;


/**
 * @brief 打开文件,读写
 */
HMYOSFILE myOsFileOpenReadWrite(const char * file_name, HMYMEMPOOL hm)
{
	os_file_t * f = NULL;

	if(NULL == file_name)
		return NULL;

	f = MyMemPoolMalloc(hm, sizeof(*f));
	if(NULL == f)
		return NULL;

	f->hm = hm;
	f->hfile = CreateFile(file_name,
		GENERIC_READ | GENERIC_WRITE,
		FILE_SHARE_READ | FILE_SHARE_WRITE,
		NULL,
		OPEN_ALWAYS,
		FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
		NULL);

	if(INVALID_HANDLE_VALUE == f->hfile)
	{
		MyMemPoolFree(hm, f);
		return NULL;
	}

	return f;
}

/**
 * @brief 以只读的方式打开文件
 */
HMYOSFILE myOsFileOpenReadOnly(const char * file_name, HMYMEMPOOL hm)
{
	os_file_t * f = NULL;

	if(NULL == file_name)
		return NULL;

	f = MyMemPoolMalloc(hm, sizeof(*f));
	if(NULL == f)
		return NULL;

	f->hm = hm;
	f->hfile = CreateFile(file_name,
		GENERIC_READ,
		0,
		NULL,
		OPEN_EXISTING,
		FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
		NULL);

	if(INVALID_HANDLE_VALUE == f->hfile)
	{
		MyMemPoolFree(hm, f);
		return NULL;
	}

	return f;
}

/**
 * @brief 以独占的方式打开文件
 */
HMYOSFILE myOsFileOpenExclusive(const char * file_name, HMYMEMPOOL hm)
{
	os_file_t * f = NULL;

	if(NULL == file_name)
		return NULL;

	f = MyMemPoolMalloc(hm, sizeof(*f));
	if(NULL == f)
		return NULL;

	f->hm = hm;
	f->hfile = CreateFile(file_name,
		GENERIC_READ | GENERIC_WRITE,
		0,
		NULL,
		CREATE_ALWAYS,
		FILE_FLAG_RANDOM_ACCESS,
		NULL);

	if(INVALID_HANDLE_VALUE == f->hfile)
	{
		MyMemPoolFree(hm, f);
		return NULL;
	}

	return f;
}

/**
 * @brief 关闭文件
 */
int myOsFileClose(HMYOSFILE hf)
{
	if(NULL == hf)
		return -1;

	if(0 == CloseHandle(hf->hfile))
		return -1;

	MyMemPoolFree(hf->hm, hf);

	return 0;
}

/**
 * @brief 同步文件至辅存
 * @return 0:成功 -1:失败
 */
int myOsFileSyn(HMYOSFILE hf)
{
	if(NULL == hf || INVALID_HANDLE_VALUE == hf->hfile)
		return -1;

	if(FlushFileBuffers(hf->hfile))
		return 0;

	return -1;
}

/**
 * @brief 写文件
 * @return 0:成功 -1:失败, -2:未写满指定字节
 */
int myOsFileWrite(HMYOSFILE hf, const void * data, size_t data_size, size_t * write_size)
{
	int rc = 0;
	DWORD wrote = 0;
	DWORD total_wrote = 0;

	if(NULL == hf || INVALID_HANDLE_VALUE == hf->hfile)
		return -1;

	assert(data_size > 0);

	while(data_size 
		&& (rc = WriteFile(hf->hfile, data, (DWORD)data_size, &wrote, 0))
		&& wrote > 0 
		&& wrote <= data_size)
	{
		data_size -= wrote;

		total_wrote += wrote;

		data = &((char*)data)[wrote];
	}

	if(!total_wrote)
		return -1;

	if(write_size)
		*write_size = total_wrote;

	if(!rc || data_size > wrote)
		return -2;

	return 0;
}

/**
 * @brief 读文件
 * @return 0:成功 -1:失败
 */
int myOsFileRead(HMYOSFILE hf, void * data, size_t data_size, size_t * read_size)
{
	DWORD got;
	if(NULL == hf || INVALID_HANDLE_VALUE == hf->hfile)
		return -1;

	if(read_size)
		*read_size = 0;

	if(!ReadFile(hf->hfile, data, (DWORD)data_size, &got, 0))
		got = 0;

	if(read_size)
		*read_size = got;

	if(got == (DWORD)data_size)
		return 0;
    
	return -1;
}

/**
 * @brief 移动当前的文件指针至off_set(相对于文件头)
 * @return 0:成功 -1:失败
 */
int myOsFileSeek(HMYOSFILE hf, int64 off_set)
{
	DWORD rc;
	LONG upperBits = (LONG)(off_set>>32);
	LONG lowerBits = (LONG)(off_set & 0xffffffff);

	if(NULL == hf || INVALID_HANDLE_VALUE == hf->hfile)
		return -1;

	rc = SetFilePointer(hf->hfile, lowerBits, &upperBits, FILE_BEGIN);

	if(rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR)
		return -1;

	return 0;
}

/**
 * @brief 删除文件
 * @return 0:成功 -1:失败
 */
int myOsFileDel(const char * file_name)
{
	if(NULL == file_name)
		return -1;

	if(0 == DeleteFile(file_name))
		return -1;

	return 0;
}

/**
 * @brief 获取文件的大小
 * @return 0:成功 -1:失败
 */
int myOsFileSize(HMYOSFILE hf, int64 * file_size)
{
	DWORD upperBits, lowerBits;

	if(NULL == hf || NULL == file_size)
		return -1;

	lowerBits = GetFileSize(hf->hfile, &upperBits);
	*file_size = (((int64)upperBits)<<32) + lowerBits;

	return 0;
}

/**
 * @brief 判断文件是否存在
 * @return 0:文件不存在 非零:文件存在
 */
int myOsFileExists(const char * file_name)
{
	return GetFileAttributes(file_name) != 0xffffffff;
}

/**
 * @brief 栽减文件
 * @return 0:成功, -1:失败
 */
int myOsFileTruncate(HMYOSFILE hf, int64 nByte)
{
	LONG upperBits = (LONG)(nByte>>32);

	if(NULL == hf)
		return -1;

	SetFilePointer(hf->hfile, (LONG)nByte, &upperBits, FILE_BEGIN);
	SetEndOfFile(hf->hfile);

	return 0;
}