#include "fs.h"void FDTable_init(struct FilePtr *fd[]){   int i;   for(i=0;i<MAX_FD;i++)      fd[i]=0;   fd[0]=fd[1]=fd[2]=(struct FilePtr *)-1;                          // reserve them. we should open fd 0,1,2 for                         // /dev/tty, but do it later.}int FDTable_get_empty_entry(struct FilePtr *fd[]){   int i;   for(i=0;i<MAX_FD;i++)      if (fd[i]==0) return i;   panic("no empty entry in fd table\n");}int FDTable_report_new_fd(struct FilePtr *fd[],struct FilePtr *fpt){   int x = FDTable_get_empty_entry(fd);   fd[x] = fpt;   return x;}