int fs_write(int fd, void *buf, int len)
{
if ((fd >= 0) && (fd < NR_FILES) && (curenv->file[fd].opened == true))
{
int i;
struct inode node;
unsigned int ioff = directory_d.entries[fd].inode_offset;
readsect((void*)node.data_block_offsets,ioff + 201);
int length = min(len,directory_d.entries[fd].file_size-curenv->file[fd].offset);
unsigned int begin = curenv->file[fd].offset / 512;
unsigned int begin_off = curenv->file[fd].offset % 512;
unsigned int end = (curenv->file[fd].offset + length) / 512;
unsigned int end_off = (curenv->file[fd].offset + length) % 512;
if (begin == end)
{
char sect[512];
readsect((void*)sect,node.data_block_offsets[begin] + 201);
for (i = 0;i < len;i++)
{
sect[begin_off + i] = ((char*)buf)[i];
}
writesect((void*)sect,node.data_block_offsets[begin] + 201);
}
else
{
char sect[512];
readsect((void*)sect,node.data_block_offsets[begin] + 201);
for (i = 0;i < 512 - begin_off;i++)
{
sect[begin_off + i] = ((char*)buf)[i];
}
writesect((void*)sect,node.data_block_offsets[begin]);
buf = ((char*)buf) + 512 - begin_off;
for (i = begin + 1;i < end;i++)
{
writesect(buf,node.data_block_offsets[i] + 201);
buf = ((char*)buf)+512;
}
readsect((void*)sect,node.data_block_offsets[end] + 201);
for (i = 0;i < end_off;i++)
{
sect[i] = ((char*)buf)[i];
}
writesect((void*)sect,node.data_block_offsets[end] + 201);
}
curenv->file[fd].offset += length;
return length;
}
else
{
printk("fs_write fails!\n");
return -1;
}
}
void writesector(int sectornumber, char* buffer)
{
int sec,head,cyl;
sec=mod(sectornumber,0x12)+1;
head=mod(div(sectornumber,0x12),2);
cyl=div(sectornumber,0x24);
writesect(buffer,sec,head,cyl);
}
/*writes buffer to a sector*/
void writesector(int sectornumber, char* buffer)
{
int sec,head,cyl;
/*convert to CHS*/
sec=mod(sectornumber,0x12)+1;
head=mod(mydiv(sectornumber,0x12),2);
cyl=mydiv(sectornumber,0x24);
writesect(buffer,sec,head,cyl);
}
