📄 sd_fat.c
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{
SD_DiskRead(Dirs, FatRsvdSecCnt+FatFATSz*2+i, 1);
for (j = 0; j < 16; j++)
{
/* 说明找到个删除的一个条目位置 */
switch (Dirs[j].DIR_Name[0])
{
case 0x00: /* 说明找到个空条目位置 */
case 0xE5: /* 说明找到个删除条目位置 */
memcpy(Dirs[j].DIR_Name, CmpStr, 11);
Dirs[j].DIR_Attr = 0x20;
Dirs[j].DIR_CrtData.Day = 26;
Dirs[j].DIR_CrtData.Mon = 3;
Dirs[j].DIR_CrtData.Year = 2004;
Dirs[j].DIR_WrtData = Dirs[j].DIR_RedData = Dirs[j].DIR_CrtData;
Dirs[j].DIR_LFstClus = 0;
Dirs[j].DIR_FileSize = 0;
fp->FDT_Num = FatRsvdSecCnt+FatFATSz*2+i;
fp->FDT_Index = j;
SD_DiskWrite(Dirs, FatRsvdSecCnt+FatFATSz*2+i, 1);
return fp;
}
}
}
free(fp);
return NULL; /* 说明根目录不足，退出 */
}
}
}
free(fp);
return NULL; /* 说明空间不足，退出 */
}
}
else /* 说明不在根目录下 */
{
if (Mode == CRWBinary) /* 创建文件时(并且此文件不存在)用于记录此目录启始簇 */
CuIndex2 = CuIndex;
OUT4:/**********/
for (i = 0; i < FatSecPerClus; i++)
{
SD_DiskRead(Dirs, FatRsvdSecCnt+FatFATSz*2+FatRootEntCnt/16+(CuIndex-2)*FatSecPerClus+i, 1);
for (j = 0; j < 16; j++)
{
/* 记录空闲条目位置，以便在新建文件时减少搜索 */
if ((Dirs[j].DIR_Name[0] == 0x00 || Dirs[j].DIR_Name[0] == 0xE5)
&& CuIndexCreat == 0 && Mode == CRWBinary)
{
/* 所在扇区位置 */
CuIndexCreat = FatRsvdSecCnt+FatFATSz*2+FatRootEntCnt/16+(CuIndex-2)*FatSecPerClus+i;
/* 记录此条目在扇区的位置 */
CreatIndex = j;
}
for (l = 0; l < 11; l++)
if (Dirs[j].DIR_Name[l] != CmpStr[l]) break;
/* 若为创建文件 */
if (Mode == CRWBinary)
{
/* 说明找到匹配的文件名-目录 */
if (l == 11 && (Dirs[j].DIR_Attr & 0x10) == 0x10)
{
free(fp);
return NULL;
}
}
if ((Dirs[j].DIR_Attr & 0x20) != 0x20) continue; /* 若不为目录（文件？）直接到下一个 */
if (l == 11) /* 说明找到匹配的文件名 */
{
switch (Mode)
{
case ORWBinary:
fp->FDT_Num = FatRsvdSecCnt+FatFATSz*2+FatRootEntCnt/16+(CuIndex-2)*FatSecPerClus+i;
fp->FDT_Index = j;
fp->FileSize = Dirs[j].DIR_FileSize;
fp->FileStart = Dirs[j].DIR_LFstClus;
return fp;
case DelFile: /* 删除指定文件 */
case CRWBinary:
fp->FDT_Num = FatRsvdSecCnt+FatFATSz*2+FatRootEntCnt/16+(CuIndex-2)*FatSecPerClus+i;
fp->FDT_Index = j;
fp->FileSize = 0;
fp->FileStart = Dirs[j].DIR_LFstClus;
/* 改写文件条目信息 */
Dirs[j].DIR_FileSize = Dirs[j].DIR_LFstClus = 0;
SD_DiskWrite(Dirs, FatRsvdSecCnt+FatFATSz*2+FatRootEntCnt/16+(CuIndex-2)*FatSecPerClus+i, 1);
/* 删除指定文件 */
if (Mode == DelFile)
{
Dirs[j].DIR_Name[0] = 0xE5;
SD_DiskWrite(Dirs, FatRsvdSecCnt+FatFATSz*2+FatRootEntCnt/16+(CuIndex-2)*FatSecPerClus+i, 1);
}
CuIndex = fp->FileStart;
if (CuIndex > 0) /* 说明有此文件有内容 */
{
OUT5:/******************************/
OldFatIndex = CuIndex/256;
SD_DiskRead(Dirs, FatRsvdSecCnt+OldFatIndex, 1);
CuValue = (UINT16 *)Dirs;
OUT8:/**********************************/
if ((CuIndex2=CuValue[CuIndex%256]) != 0xFFFF)
{
CuValue[CuIndex%256] = 0;
CuIndex = CuIndex2;
if (OldFatIndex != CuIndex/256)
{
SD_DiskWrite(Dirs, FatRsvdSecCnt+OldFatIndex, 1);
goto OUT5;
}
else
{
goto OUT8;
}
}
else
{
CuValue[CuIndex%256] = 0;
SD_DiskWrite(Dirs, FatRsvdSecCnt+OldFatIndex, 1);
}
return fp;
}
else /* 说明无此内容，选找空闲簇 */
{
/* 删除指定文件 */
if (Mode == DelFile) return fp;
for (i = 0; i < FatFATSz; i++)
{
SD_DiskRead(Dirs, FatRsvdSecCnt+i, 1);
CuValue = (UINT16 *)Dirs;
for (j = 0; j < 256; j++)
{
if (CuValue[j] == 0x0000) /* 说明找到空闲位置 */
{
fp->FileStart = i*256+j; /* 记录此文件开始簇 */
return fp;
}
}
}
free(fp);
return NULL; /* 说明空间不足，退出 */
}
}
}
}
}
SD_DiskRead(Dirs, FatRsvdSecCnt+CuIndex/256, 1);
CuValue = (UINT16 *)Dirs;
if (CuValue[CuIndex%256] == 0xFFFF) /* 说明没有此目录，返回空 */
{
switch (Mode)
{
case DelFile: /* 删除指定文件，且无此文件 */
case ORWBinary:
free(fp);
return NULL; /* 说明没有此文件返回空 */
case CRWBinary:
if (CuIndexCreat > 0) /* 说明已经找到空闲条目 */
{
for (i = 0; i < FatFATSz; i++)
{
SD_DiskRead(Dirs, FatRsvdSecCnt+i, 1);
CuValue = (UINT16 *)Dirs;
for (j = 0; j < 256; j++)
{
if (CuValue[j] == 0x0000) /* 说明找到空闲位置 */
{
fp->FDT_Num = CuIndexCreat;
fp->FDT_Index = CreatIndex;
fp->FileSize = 0;
fp->FileStart = i*256+j; /* 记录此文件开始簇 */
SD_DiskRead(Dirs, CuIndexCreat, 1);
memcpy(Dirs[CreatIndex].DIR_Name, CmpStr, 11);
Dirs[CreatIndex].DIR_Attr = 0x20;
Dirs[CreatIndex].DIR_CrtData.Day = 26;
Dirs[CreatIndex].DIR_CrtData.Mon = 3;
Dirs[CreatIndex].DIR_CrtData.Year = 2004;
Dirs[CreatIndex].DIR_WrtData = Dirs[CreatIndex].DIR_RedData = Dirs[CreatIndex].DIR_CrtData;
Dirs[CreatIndex].DIR_LFstClus = 0;
Dirs[CreatIndex].DIR_FileSize = 0;
SD_DiskWrite(Dirs, CuIndexCreat, 1);
return fp;
}
}
}
free(fp);
return NULL; /* 说明控间不足 */
}
else /* 说明此目录当前已满，扩充簇 */
{
CuIndexCreat = 0;
for (i = 0; i < FatFATSz; i++)
{
SD_DiskRead(Dirs, FatRsvdSecCnt+i, 1);
CuValue = (UINT16 *)Dirs;
for (j = 0; j < 256; j++)
{
if (CuValue[j] == 0x0000) /* 说明找到空闲位置 */
{
if (CuIndexCreat == 0)
{
fp->FileSize = 0;
CuIndexCreat = i*256+j; /* 记录此文件开始簇 */
}
else /* 记录当前目录扩充到多少簇 */
{
fp->FileStart = i*256+j;
SD_DiskRead(Dirs, FatRsvdSecCnt+CuIndex/256, 1);
CuValue = (UINT16 *)Dirs;
CuValue[CuIndex%256] = CuIndexCreat;
SD_DiskWrite(Dirs, FatRsvdSecCnt+CuIndex/256, 1);
CuIndex = CuIndexCreat;
SD_DiskRead(Dirs, FatRsvdSecCnt+CuIndex/256, 1);
CuValue = (UINT16 *)Dirs;
CuValue[CuIndex%256] = 0xFFFF;
SD_DiskWrite(Dirs, FatRsvdSecCnt+CuIndex/256, 1);
fp->FDT_Num = FatRsvdSecCnt+FatFATSz*2+FatRootEntCnt/16+(CuIndex-2)*FatSecPerClus;
fp->FDT_Index = 0;
memset(Dirs, 0, 512);
for (i = 0; i < FatSecPerClus; i++)
SD_DiskWrite(Dirs, fp->FDT_Num+i, 1);
memcpy(Dirs[0].DIR_Name, CmpStr, 11);
Dirs[0].DIR_Attr = 0x20;
Dirs[0].DIR_CrtData.Day = 26;
Dirs[0].DIR_CrtData.Mon = 3;
Dirs[0].DIR_CrtData.Year = 2004;
Dirs[0].DIR_WrtData = Dirs[0].DIR_RedData = Dirs[0].DIR_CrtData;
Dirs[0].DIR_LFstClus = 0;
Dirs[0].DIR_FileSize = 0;
SD_DiskWrite(Dirs, fp->FDT_Num, 1);
return fp;
}
}
}
}
free(fp);
return NULL; /* 说明控间不足 */
}
}
}
else /* 继续搜索下一簇 */
{
CuIndex = CuValue[CuIndex%256];
goto OUT4;
}
}
}
}
}
/* 调整文件位置指针 */
void SD_fseek(SD_FILE *fp, INT32 offset, UINT8 Mode)
{
DIR Dirs[16];
if (fp == NULL) return ;
SD_DiskRead(Dirs, fp->FDT_Num, 1);
switch (Mode)
{
case SDSEEK_SET:
fp->FileSeek = 0;
fp->FileSeek += offset;
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