chkhostid.c

来自「从磁带机读取地震纪录原始代码,包括地震数据格式,2格式等」· C语言 代码 · 共 49 行

/************************************************
 Name:    IEEE2IBM
 Version: 2.0
 Date:    1996.07
 Purpose: Convert IEEE floating point numbers
	  to IBM floating point numbers.
************************************************/
void ieee2ibm (float *fv,int sw,int n)
{
 float *rin;
 unsigned char *cbuf,exp,tem;
 unsigned long *umantis,usignl;
 long expl,*mantis;
 int i;
 rin=fv;
 for (i=0;i<n;i++,rin++) {
     umantis=(unsigned long*)rin;
     cbuf=(unsigned char*)rin;
     usignl= *umantis & 0x80000000;
     exp=(*umantis>>23);
     *umantis=((*umantis) | 0x00800000) & 0x00ffffff;
     exp-=126;
     if (exp % 4) {
       *umantis>>=(4-exp % 4);
	exp+=4;
     } /* end if */
     exp>>=2;
     exp+=64;
     expl=(long) exp;
     expl=(expl << 24) & 0x7f000000;
     *umantis=(*umantis) | expl | usignl;
     if (sw) {
       tem=cbuf[0];cbuf[0]=cbuf[3];cbuf[3]=tem;
       tem=cbuf[1];cbuf[1]=cbuf[2];cbuf[2]=tem;
     } /* end if (sw) */
 } /* end for i */
}  /* end ieee2ibm */

void chkhostid(void)
{ 
  long lid;
  lid=gethostid();
  if (lid!=0x7235c21aL && lid!=0x727359c0L) {
     printf("\n Illegal user !\n");
     exit(-1);
  }
}