dbf.c

jpeg压缩程序

/**************************************************/
/*           DBMS Engine source File              */
/*Copyright:WangHaiyun,HiSoft                     */
/*Date:1996/08/01                                 */
/*Last Modified:                                  */
/**************************************************/
#include<stdio.h>
#include<stdarg.h>
#include<fcntl.h>
#include<io.h>
#include<ctype.h>
#include<stdlib.h>
#include<c_base.h>

/*Open database*/
DBF *_Cdecl use(char* dbfname)
{
DBF *dbf;
unsigned char byte_buf;
int i;
dbf=(DBF *)malloc(sizeof(DBF));
if((dbf->handle=open(dbf_name,O_RDWR|O_DENYNONE|O_BINARY))
      ==-1)
{
free(dbf);
return NULL;
}
read(dbf->handle,&byte_buf,1);
if(byte_buf!=0x03&&byte_buf!=0x83)
{
  close(dbf->handle);
  free(dbf);
  return NULL;
}
read(dbf->handle,&byte_buf,1);
dbf->modify_date.da_year=byte_buf+1900;
read(dbf->handle,&byte_buf,1);
dbf->modify_date.da_mon=byte_buf;
read(dbf->handle,&byte_buf,1);
dbf->modify_date.da_day=byte_buf;
read(dbf->handle,&(dbf->rec_count),4);
read(dbf->handle,&(dbf->stru_len),2);
dbf->fld_count=(dbf->stru_len-33)/32;
read(dbf->handle,&(dbf->rec_len),2);
dbf->dbf_stru=(DBF_STRU*)malloc(dbf->fld_count*sizeof(DBF_STRU));
lseek(dbf->handle,32L,SEEK_SET);
for(i=0;i<dbf->fld_count;i++)
{
  read(dbf->handle,dbf->stru[i].field_name,11);
  read(dbf->handle,&(dbf->dbf_stru[i].field_type),1);
  read(dbf->handle,&(dbf->dbf_stru[i].field_pos),2);
  lseek(dbf->handle,2L,SEEK_CUR);
  read(dbf->handle,&(dbf->dbf_stru[i].field_len),1);
  read(dbf->handle,&(dbf->dbf_stru[i].field_dec),1);
  lseek(dbf->handle,14L,SEEK_CUR);
}
lseek(dbf->handle,1L,SEEK_CUR);
dbf->curr_rec=(char*)malloc(dbf->rec_len+1);
if(dbf->rec_count>0)
{
  dbf->rec_no=1;
  read(dbf->handle,dbf->curr_rec,dbf->rec_len);
  dbf->curr_rec[dbf->rec_len]=0;
  dbf->eof=NO;
}
else
{
  for(i=0;i<dbf->rec_len;i++)
    dbf->curr_rec[i]=' ';
    dbf->curr_rec[dbf->rec_len]=0;
    dbf->rec_no=0;
    dbf->eof=YES;
}
dbf->update_tag=NO;
return(dbf);
}
/*     Close database   */
int _Cdecl close_DBF(DBF* dbf)
{
char temp[3];
if(dbf==NULL)
  return 0;
if(dbf->update_tag==YES)
{
   getdate(&(dbf->modify_date));
   lseek(dbf->handle,1L,SEEK_SET);
   tmp[0]=dbf->modify_date.da_year-1900;
   tmp[1]=dbf->modify_date.da_mon;
   tmp[2]=dbf->modify_date.da_day;
   write(dbf->handle,tmp,3);
   write(dbf->handle,&(dbf->rec_count),4);
}
free(dbf->curr_rec);
free(dbf->dbf_stru);
close(dbf->handle);
free(dbf);
return 1;
}

/*Database file pointer relative moving function */
long _Cdecl skip(DBF *dbf,int step)
{
 if(dbf==NULL||dbf->rec_no==0)
    return 0;
 if(dbf->rec_no+step<1)
    step=1-dbf->rec_no;
 else if(dbf->rec_no+step>dbf->rec_count)
 {
  step=dbf->rec_count-dbf->rec_no;
  dbf->eof=YES;
 }
 dbf->rec_no+=step;
 if(step!=1)
   lseek(dbf->handle,dbf->rec_len*(step-1),SEEK_CUR);
 read(dbf->handle,dbf->curr_rec,dbf->rec_len);
 return(dbf->rec_no);
}

/*get current record*/
long _Cdecl get_record(DBF *dbf,char *fmt,...)
{
 va_list arglist;
 int *ival;
 long *lval;
 char *sval;
 double *fval;
 GRAPH_TEXT *gval;
 struct date *dval;
 int no=1;
 int tmp;
 char *p;
 char word[MAX_FIELD_LEN];
 if(dbf==NULL||dbf->eof==YES)
 return 0;
 va_start(arglist,fmt);
 for(;*fmt;fmt++)
 {
   tmp=0;
   while(*fmt&&isdigit(*fmt))
   {
   tmp=tmp*10+*fmt-'0';
   fmt++;
   }
   no=tmp==0?no:tmp;
   if(*fmt=='i'||*fmt=='l'||*fmt=='f'||*fmt=='d'
       ||*fmt=='s'||*fmt=='c'||*fmt=='g'||*fmt=='m')
   {
   p=dbf->curr_rec+dbf->dbf_stru[no-1].field_pos;
     strncpy(word,p,dbf->dbf_stru[no-1].field_len);
     word[dbf->dbf_stru[no-1].field_len]=0;
     switch(*fmt)
     {
      case 'i':
        ival=va_arg(arglist,int*);
        *ival=atoi(word);
        break;
      case 'l':
        lval=va_arg(arglist,long*);
        *lval=atol(word);
        break;
      case 'f':
        fval=va_arg(arglist,double *);
        *fval=atof(word);
        break;
      case 'd':/*note the 2000 year problem*/
        dval=va_arg(arglist,struct date *);
        dval->da_day=atoi(word+6);
        word[6]=0;
        dval->da_mon=atoi(word+4);
        word[4]=0;
        dval->da_year=atoi(word);
        break;
      case 's':
        sval=va_arg(arglist,char *);
        strcpy(sval,word);
        break;
      case 'c':
        ival=va_arg(arglist,int *);
        *ival=word[0];
        break;
      case 'g':
        gval=va_arg(arglist,GRAPH_TEXT *);
        memcpy(gval,word,10);
        break;
      case 'm':
        lval=va_arg(arglist,long *);
        *lval=atol(word);
        break;
    }
       no++;
   }
  }
 va_end(arglist);
 return(dbf->rec_no);
}

/*write database file current record function*/
long _Cdecl put_record(DBF *dbf,char *fmt,...)
{
va_list arglist;
int ival;
long lval;
char *sval;
double fval;
struct date dval;
GRAPH_TEXT gval;
int no=1;
int i;
int tmp;
char *p;
char word[MAX_FIELD_LEN];
char format[20];
if(dbf==NULL||dbf->rec_no==0||dbf->eof==YES)
  return 0;
va_start(arglist,fmt);
for(;*fmt;fmt++)
{
        tmp=0;
        while(*fmt&&isdigit(*fmt))
        {
        tmp=tmp*10+*fmt-'0';
        fmt++;
        }
        no=tmp==0?no:tmp;
        if(*fmt=='i'||*fmt='l'||*fmt=='f'||*fmt=='d'\
          ||*fmt=='s'||*fmt=='c'||*fmt=='m'||*fmt=='g')
          {
          strcpy(format,"%");
          switch(dbf->dbf_stru[no-1].field_type)
            {
            case 'N':
              itoa(dbf->dbf_stru[no-1].field_len,word,10);
              strcat(format,word);
              if(dbf->dbf_stru[no-1].field_dec==0)
                strcat(format,"d");
                else
                {
                itoa(dbf->dbf_stru[no-1].field_dec,word,10);
                strcat(format,".");
                strcat(format,word);
                strcat(format,"f");
                 }
                 break;
              case 'C':
                strcat(format,"-");
                itoa(dbf->dbf_stru[no-1].field_len,word,10);
                strcat(format,word);
                strcat(format,"s");
                break;
              case 'D':
                strcat(format,"4d%02d%02d");
                break;
              case 'L':
                format[0]='l';
                break;
              case 'M':
                strcat(format,"010d");
           }
          switch(*fmt)
          {
            case 'i':
              ival=va_arg(arglist,int);
              if(dbf->dbf_stru[no-1].field_dec==0)
                sprintf(word,format,ival);
              else
              {
               fval=ival;
               sprintf(word,format,fval);
               }
               break;
             case 'l':
               lval=va_arg(arglist,long);
               if(dbf->dbf_stru[no-1].field_dec==0)
                sprintf(word,format,lval);
              else
              {
               fval=lval;
               sprintf(word,format,fval);
               }
               break;
             case 'f':
               fval=va_arg(arglist,double);
               if(dbf->dbf_stru[no-1].field_dec!=0)
                 sprintf(word,format,fval);
              else
              {
               lval=fval;
               sprintf(word,format,lval);
               }
               break;
             case 'd':
               dval=va_arg(arglist,struct date);
               sprintf(word,format,dval.da_year,dval.da_mon,dval.da_day);
               break;
             case 's':
               sval=va_arg(arglist,char *);
               sprintf(word,format,sval);
               break;
             case 'c':
               ival=va_arg(arglist,int);
               word[0]=format[0]=='l'?((ival=='y'||ival=='Y'||\
                 ival=='t'||ival=='T')?'T':'F'):ival;
               word[1]=0;
               break;
             case 'm':
               lval=va_arg(arglist,long);
               sprintf(word,format,lval);
               break;
             case 'g':
               gval=va_arg(arglist,GRAPH_TEXT);
               memcpy(word,&gval,10);
              }
              p=dbf->curr_rec+dbf->dbf_stru[no-1].field_pos;
              for(i=0;i<dbf->dbf_stru[no-1].field_len;i++)
                *p++=word[i];
              no++;
              }
          }
        va_end(arglist);
        lseek(dbf->handle,-dbf->rec_len,SEEK_CUR);
        write(dbf->handle,dbf->curr_rec,dbf->rec_len);