fat_open.c

本资料包括建立在SD卡和NANDFLASH上的文件系统

/*
**********************************************************************
*                          Micrium, Inc.
*                      949 Crestview Circle
*                     Weston,  FL 33327-1848
*
*                            uC/FS
*
*             (c) Copyright 2001 - 2003, Micrium, Inc.
*                      All rights reserved.
*
***********************************************************************

----------------------------------------------------------------------
File        : fat_open.c
Purpose     : FAT routines for open/delete files
----------------------------------------------------------------------
Known problems or limitations with current version
----------------------------------------------------------------------
None.
---------------------------END-OF-HEADER------------------------------
*/

/*********************************************************************
*
*             #include Section
*
**********************************************************************
*/

#include "fs_conf.h"
#include "fs_port.h"
#ifndef FS_FARCHARPTR
#define FS_FARCHARPTR char *
#endif
#include "fs_dev.h"
#include "fs_api.h"
#include "fs_fsl.h"
#include "fs_int.h"
#include "fs_os.h"
#include "fs_lbl.h"
#include "fs_fat.h"
#include "fs_clib.h"


/*********************************************************************
*
*             #define constants
*
**********************************************************************
*/

#ifndef FS_FAT_NOFAT32
  #define FS_FAT_NOFAT32        0
#endif /* FS_FAT_NOFAT32 */


/*********************************************************************
*
*             Local functions
*
**********************************************************************
*/

/*********************************************************************
*
*             _FS_fat_find_file
*
  Description:
  FS internal function. Find the file with name pFileName in directory
  DirStart. Copy its directory entry to pDirEntry.
  
  Parameters:
  Idx         - Index of device in the device information table 
                referred by FS__pDevInfo.
  Unit        - Unit number.
  pFileName   - File name. 
  pDirEntry   - Pointer to an FS__fat_dentry_type data structure.
  DirStart    - 1st cluster of the directory.
  DirSize     - Sector (not cluster) size of the directory.
 
  Return value:
  >=0         - File found. Value is the first cluster of the file.
  <0          - An error has occured.
*/

static FS_i32 _FS_fat_find_file(int Idx, FS_u32 Unit, const char *pFileName,
                                    FS__fat_dentry_type *pDirEntry,
                                    FS_u32 DirStart, FS_u32 DirSize) {
  FS__fat_dentry_type *s;
  FS_u32 i;
  FS_u32 dsec;
  int len;
  int err; 
  int c;
  char *buffer;

  buffer = FS__fat_malloc(FS_FAT_SEC_SIZE);
  if (!buffer) {
    return -1;
  }
  len = FS__CLIB_strlen(pFileName);
  if (len > 11) {
    len = 11;
  }
  /* Read directory */
  for (i = 0; i < DirSize; i++) {
    dsec = FS__fat_dir_realsec(Idx, Unit, DirStart, i);
    if (dsec == 0) {
      FS__fat_free(buffer);
      return -1;
    }
    err = FS__lb_read(FS__pDevInfo[Idx].devdriver, Unit, dsec, (void*)buffer);
    if (err < 0) {
      FS__fat_free(buffer);
      return -1;
    }
    s = (FS__fat_dentry_type*)buffer;
    while (1) {
      if (s >= (FS__fat_dentry_type*)(buffer + FS_FAT_SEC_SIZE)) {
        break;  /* End of sector reached */
      }
      c = FS__CLIB_strncmp((char*)s->data, pFileName, len);
      if (c == 0) {  /* Name does match */
        if (s->data[11] & FS_FAT_ATTR_ARCHIVE) {
          break;  /* Entry found */
        }
      }
      s++;
    }
    if (s < (FS__fat_dentry_type*)(buffer + FS_FAT_SEC_SIZE)) {
      /* Entry found. Return number of 1st block of the file */
      if (pDirEntry) {
        FS__CLIB_memcpy(pDirEntry, s, sizeof(FS__fat_dentry_type));
      }
      FS__fat_free(buffer);
      dsec  = (FS_u32)s->data[26];
      dsec += (FS_u32)s->data[27] * 0x100UL;
      dsec += (FS_u32)s->data[20] * 0x10000UL;
      dsec += (FS_u32)s->data[21] * 0x1000000UL;
      return ((FS_i32)dsec);
    }
  }
  FS__fat_free(buffer);
  return -1;
}


/*********************************************************************
*
*             _FS_fat_IncDir
*
  Description:
  FS internal function. Increase directory starting at DirStart.
  
  Parameters:
  Idx         - Index of device in the device information table 
                referred by FS__pDevInfo.
  Unit        - Unit number.
  DirStart    - 1st cluster of the directory.
  pDirSize    - Pointer to an FS_u32, which is used to return the new 
                sector (not cluster) size of the directory.
 
  Return value:
  ==1         - Success.
  ==-1        - An error has occured.
*/

static int _FS_fat_IncDir(int Idx, FS_u32 Unit, FS_u32 DirStart, FS_u32 *pDirSize) {
  FS_u32 i;
  FS_u32 dsec;
  FS_i32 last;
  char *buffer;
  int err;

  if (DirStart == 0) { 
    /* Increase root directory only, if not FAT12/16  */
    i = FS__FAT_aBPBUnit[Idx][Unit].RootEntCnt;
    if (i != 0) {
      return -1;  /* Not FAT32 */
    }
  }
  last = FS__fat_FAT_find_eof(Idx, Unit, DirStart, 0);
  if (last < 0) {
    return -1;  /* No EOF marker found */
  }
  last = FS__fat_FAT_alloc(Idx, Unit, last);  /* Allocate new cluster */
  if (last < 0) {
    return -1;
  }
  *pDirSize = *pDirSize + FS__FAT_aBPBUnit[Idx][Unit].SecPerClus;
  /* Clean new directory cluster */
  buffer = FS__fat_malloc(FS_FAT_SEC_SIZE);
  if (!buffer) {
    return -1;
  }
  FS__CLIB_memset(buffer, 0x00, (FS_size_t)FS_FAT_SEC_SIZE);
  for (i = *pDirSize - FS__FAT_aBPBUnit[Idx][Unit].SecPerClus; i < *pDirSize; i++) {
    dsec = FS__fat_dir_realsec(Idx, Unit, DirStart, i);
    if (dsec == 0) {
      FS__fat_free(buffer);
      return -1;
    }
    err = FS__lb_write(FS__pDevInfo[Idx].devdriver, Unit, dsec, (void*)buffer);
    if (err < 0) {
      FS__fat_free(buffer);
      return -1;
    }
  }
  FS__fat_free(buffer);
  return 1;
}


/*********************************************************************
*
*             _FS_fat_create_file
*
  Description:
  FS internal function. Create a file in the directory specified
  with DirStart. Do not call, if you have not checked before for 
  existing file with name pFileName.

  Parameters:
  Idx         - Index of device in the device information table 
                referred by FS__pDevInfo.
  Unit        - Unit number, which is passed to the device driver.
  pFileName   - File name. 
  DirStart    - Start of directory, where to create pDirName.
  DirSize     - Sector size of the directory starting at DirStart.
  
  Return value:
  >=0         - 1st cluster of the new file.
  ==-1        - An error has occured.
  ==-2        - Cannot create, because directory is full.
*/

static FS_i32 _FS_fat_create_file(int Idx, FS_u32 Unit,  const char *pFileName,
                                    FS_u32 DirStart, FS_u32 DirSize) {
  FS__fat_dentry_type *s;
  FS_u32 i;
  FS_u32 dsec;
  FS_i32 cluster;
  int len;
  int err;
  FS_u16 val;
  char *buffer;

  buffer = FS__fat_malloc(FS_FAT_SEC_SIZE);
  if (!buffer) {
    return -1;
  }
  len = FS__CLIB_strlen(pFileName);
  if (len > 11) {
    len = 11;
  }
  /* Read directory */
  for (i = 0; i < DirSize; i++) {
    dsec = FS__fat_dir_realsec(Idx, Unit, DirStart, i);
    if (dsec == 0) {
      FS__fat_free(buffer);
      return -1;
    }
    err = FS__lb_read(FS__pDevInfo[Idx].devdriver, Unit, dsec, (void*)buffer);
    if (err < 0) {
      FS__fat_free(buffer);
      return -1;
    }
    s = (FS__fat_dentry_type*)buffer;
    while (1) {
      if (s >= (FS__fat_dentry_type*)(buffer + FS_FAT_SEC_SIZE)) {
        break;  /* End of sector reached */
      }
      if (s->data[0] == 0x00) {
        break;  /* Empty entry found */
      }
      if (s->data[0] == (unsigned char)0xe5) {
        break;  /* Deleted entry found */
      }
      s++;
    }
    if (s < (FS__fat_dentry_type*)(buffer + FS_FAT_SEC_SIZE)) {
      /* Free entry found. Make entry and return 1st block of the file */
      FS__CLIB_strncpy((char*)s->data, pFileName, len);
      s->data[11] = FS_FAT_ATTR_ARCHIVE;
      /* Alloc block in FAT */
      cluster = FS__fat_FAT_alloc(Idx, Unit, -1);
      if (cluster >= 0) {
        s->data[12]     = 0x00;                           /* Res */
        s->data[13]     = 0x00;                           /* CrtTimeTenth (optional, not supported) */
        s->data[14]     = 0x00;                           /* CrtTime (optional, not supported) */
        s->data[15]     = 0x00;
        s->data[16]     = 0x00;                           /* CrtDate (optional, not supported) */
        s->data[17]     = 0x00;
        s->data[18]     = 0x00;                           /* LstAccDate (optional, not supported) */
        s->data[19]     = 0x00;
        val             = FS_X_OS_GetTime();
        s->data[22]     = (unsigned char)(val & 0xff);   /* WrtTime */
        s->data[23]     = (unsigned char)(val / 256);
        val             = FS_X_OS_GetDate();
        s->data[24]     = (unsigned char)(val & 0xff);   /* WrtDate */
        s->data[25]     = (unsigned char)(val / 256);
        s->data[26]     = (unsigned char)(cluster & 0xff);    /* FstClusLo / FstClusHi */ 
        s->data[27]     = (unsigned char)((cluster / 256) & 0xff);
        s->data[20]     = (unsigned char)((cluster / 0x10000L) & 0xff);
        s->data[21]     = (unsigned char)((cluster / 0x1000000L) & 0xff);
        s->data[28]     = 0x00;                           /* FileSize */
        s->data[29]     = 0x00;
        s->data[30]     = 0x00;
        s->data[31]     = 0x00;
        err = FS__lb_write(FS__pDevInfo[Idx].devdriver, Unit, dsec, (void*)buffer);
        if (err < 0) {
          FS__fat_free(buffer);
          return -1;
        }
      }
      FS__fat_free(buffer);
      return cluster;
    }
  }
  FS__fat_free(buffer);
  return -2;      /* Directory is full */
}


/*********************************************************************
*
*             Global functions section 1
*
**********************************************************************

  Functions in this section are global, but are used inside the FAT
  File System Layer only.
  
*/

/*********************************************************************
*
*             FS__fat_DeleteFileOrDir
*
  Description:
  FS internal function. Delete a file or directory.
  
  Parameters:
  Idx         - Index of device in the device information table 
                referred by FS__pDevInfo.
  Unit        - Unit number, which is passed to the device driver.
  pName       - File or directory name. 
  DirStart    - Start of directory, where to create pDirName.
  DirSize     - Sector size of the directory starting at DirStart.
  RmFile      - 1 => remove a file
                0 => remove a directory
  
  Return value:
  >=0         - Success. 
  <0          - An error has occured.
*/

FS_i32 FS__fat_DeleteFileOrDir(int Idx, FS_u32 Unit,  const char *pName,
                                    FS_u32 DirStart, FS_u32 DirSize, char RmFile) {
  FS__fat_dentry_type *s;
  FS_u32 dsec;
  FS_u32 i;
  FS_u32 value;
  FS_u32 fatsize;
  FS_u32 filesize;
  FS_i32 len;
  FS_i32 bytespersec;
  FS_i32 fatindex;
  FS_i32 fatsec;
  FS_i32 fatoffs;
  FS_i32 lastsec;
  FS_i32 curclst;
  FS_i32 todo;
  char *buffer;
  int fattype;
  int err;
  int err2;
  int lexp;
  int x;
  unsigned char a;
  unsigned char b;
#if (FS_FAT_NOFAT32==0)
  unsigned char c;
  unsigned char d;