//++++++++++++++++++++++++++++++++++++++++++++++++++++//
//               讀segy數據方法
//++++++++++++++++++++++++++++++++++++++++++++++++++++//
#include  <stdio.h>#include  <math.h>#include  <string.h>#include  <ctype.h>#define    LEN   3200#define    NQ2   30000void  main () {    float   ki[NQ2], ko[NQ2];    int     nflg,n,j,m,l,k,i;    int     len,len1,key,jhd,number, si, nta, ntb, nt, lz;
	short   int  gh[400];
	char    namei[50],nameo[50];
/*******************************************************/    FILE    *fp1,*fp2;    union       {         int       hd[NQ2];         float     data[NQ2];         char      buf[NQ2];         short int shd[NQ2];       }dat;
/***************************************************************************/
	 printf("input file name:  ");
	 scanf("%s",  &namei);

     printf("output file name:  ");
	 scanf("%s",  &nameo);

     fp1=fopen(namei,"rb");     if(fp1==NULL)  {printf("can't open input segy file\n");   exit(0);}     fp2=fopen(nameo,"wb");     if(fp2==NULL)  {printf(" can't open output segy file\n"); exit(0);}

     fread(&dat.buf[0],1,LEN,fp1);
     fwrite(&dat.buf[0],1,LEN,fp2);
     fread(&dat.buf[0],1,400,fp1);
	 len1=dat.shd[10];     printf ("sample numbers:   %d \n",  len1);     printf ("sample rate(ms):  %u \n",  dat.shd[8]/1000);     printf ("seg_y  flag:      %d \n",  dat.shd[12]);

/**************************************************************/
     for(i=0; i<400; i++)
	 gh[i]=dat.shd[i];

     fwrite(&dat.buf[0],1,400,fp2);     nflg=dat.shd[12];

     if(nflg==1)   len=len1*4+240;     if(nflg==2)   len=len1*4+240;             if(nflg==3)   len=len1*2+240;
     printf ("\ninput  record length:  %d \n", len);
     n=0;     jhd=60;

/************************************************************/     while ((l=fread(&dat.buf[0],1,len,fp1))>0)
	 {
        for(i=0; i<len1; i++)
        ki[i]=dat.data[i+jhd];       //  dat.hd[],   dat.shd[]  

        //filter(ki,len1,ko);        //  對數據進行各種處理

        for(i=0; i<len1; i++)
        dat.data[i+jhd]=ko[i];       //  dat.hd[],   dat.shd[]  

	    fwrite(&dat.buf[0],1,len,fp2);
		n++;
		printf("trace number: %d \n", n);
	 }
     fclose(fp1);     fclose(fp2); }