option.c

static char **g_argv;
static struct s_options *op;
static FILE *errstream;

#define ISOPT(X) ((X)[0]=='-'||(X)[0]=='+'||strchr((X),'=')!=0)

/*
** Print the command line with a carrot pointing to the k-th character
** of the n-th field.
*/
static void errline(int n, int k, FILE *err)
{
  int spcnt, i;
  if( g_argv[0] ){
    fprintf(err,"%s",g_argv[0]);
    spcnt = lemonStrlen(g_argv[0]) + 1;
  }else{
    spcnt = 0;
  }
  for(i=1; i<n && g_argv[i]; i++){
    fprintf(err," %s",g_argv[i]);
    spcnt += lemonStrlen(g_argv[i])+1;
  }
  spcnt += k;
  for(; g_argv[i]; i++) fprintf(err," %s",g_argv[i]);
  if( spcnt<20 ){
    fprintf(err,"\n%*s^-- here\n",spcnt,"");
  }else{
    fprintf(err,"\n%*shere --^\n",spcnt-7,"");
  }
}

/*
** Return the index of the N-th non-switch argument.  Return -1
** if N is out of range.
*/
static int argindex(int n)
{
  int i;
  int dashdash = 0;
  if( g_argv!=0 && *g_argv!=0 ){
    for(i=1; g_argv[i]; i++){
      if( dashdash || !ISOPT(g_argv[i]) ){
        if( n==0 ) return i;
        n--;
      }
      if( strcmp(g_argv[i],"--")==0 ) dashdash = 1;
    }
  }
  return -1;
}

static char emsg[] = "Command line syntax error: ";

/*
** Process a flag command line argument.
*/
static int handleflags(int i, FILE *err)
{
  int v;
  int errcnt = 0;
  int j;
  for(j=0; op[j].label; j++){
    if( strncmp(&g_argv[i][1],op[j].label,lemonStrlen(op[j].label))==0 ) break;
  }
  v = g_argv[i][0]=='-' ? 1 : 0;
  if( op[j].label==0 ){
    if( err ){
      fprintf(err,"%sundefined option.\n",emsg);
      errline(i,1,err);
    }
    errcnt++;
  }else if( op[j].arg==0 ){
    /* Ignore this option */
  }else if( op[j].type==OPT_FLAG ){
    *((int*)op[j].arg) = v;
  }else if( op[j].type==OPT_FFLAG ){
    (*(void(*)(int))(op[j].arg))(v);
  }else if( op[j].type==OPT_FSTR ){
    (*(void(*)(char *))(op[j].arg))(&g_argv[i][2]);
  }else{
    if( err ){
      fprintf(err,"%smissing argument on switch.\n",emsg);
      errline(i,1,err);
    }
    errcnt++;
  }
  return errcnt;
}

/*
** Process a command line switch which has an argument.
*/
static int handleswitch(int i, FILE *err)
{
  int lv = 0;
  double dv = 0.0;
  char *sv = 0, *end;
  char *cp;
  int j;
  int errcnt = 0;
  cp = strchr(g_argv[i],'=');
  assert( cp!=0 );
  *cp = 0;
  for(j=0; op[j].label; j++){
    if( strcmp(g_argv[i],op[j].label)==0 ) break;
  }
  *cp = '=';
  if( op[j].label==0 ){
    if( err ){
      fprintf(err,"%sundefined option.\n",emsg);
      errline(i,0,err);
    }
    errcnt++;
  }else{
    cp++;
    switch( op[j].type ){
      case OPT_FLAG:
      case OPT_FFLAG:
        if( err ){
          fprintf(err,"%soption requires an argument.\n",emsg);
          errline(i,0,err);
        }
        errcnt++;
        break;
      case OPT_DBL:
      case OPT_FDBL:
        dv = strtod(cp,&end);
        if( *end ){
          if( err ){
            fprintf(err,
               "%sillegal character in floating-point argument.\n",emsg);
            errline(i,(int)((char*)end-(char*)g_argv[i]),err);
          }
          errcnt++;
        }
        break;
      case OPT_INT:
      case OPT_FINT:
        lv = strtol(cp,&end,0);
        if( *end ){
          if( err ){
            fprintf(err,"%sillegal character in integer argument.\n",emsg);
            errline(i,(int)((char*)end-(char*)g_argv[i]),err);
          }
          errcnt++;
        }
        break;
      case OPT_STR:
      case OPT_FSTR:
        sv = cp;
        break;
    }
    switch( op[j].type ){
      case OPT_FLAG:
      case OPT_FFLAG:
        break;
      case OPT_DBL:
        *(double*)(op[j].arg) = dv;
        break;
      case OPT_FDBL:
        (*(void(*)(double))(op[j].arg))(dv);
        break;
      case OPT_INT:
        *(int*)(op[j].arg) = lv;
        break;
      case OPT_FINT:
        (*(void(*)(int))(op[j].arg))((int)lv);
        break;
      case OPT_STR:
        *(char**)(op[j].arg) = sv;
        break;
      case OPT_FSTR:
        (*(void(*)(char *))(op[j].arg))(sv);
        break;
    }
  }
  return errcnt;
}

int OptInit(char **a, struct s_options *o, FILE *err)
{
  int errcnt = 0;
  g_argv = a;
  op = o;
  errstream = err;
  if( g_argv && *g_argv && op ){
    int i;
    for(i=1; g_argv[i]; i++){
      if( g_argv[i][0]=='+' || g_argv[i][0]=='-' ){
        errcnt += handleflags(i,err);
      }else if( strchr(g_argv[i],'=') ){
        errcnt += handleswitch(i,err);
      }
    }
  }
  if( errcnt>0 ){
    fprintf(err,"Valid command line options for \"%s\" are:\n",*a);
    OptPrint();
    exit(1);
  }
  return 0;
}

int OptNArgs(void){
  int cnt = 0;
  int dashdash = 0;
  int i;
  if( g_argv!=0 && g_argv[0]!=0 ){
    for(i=1; g_argv[i]; i++){
      if( dashdash || !ISOPT(g_argv[i]) ) cnt++;
      if( strcmp(g_argv[i],"--")==0 ) dashdash = 1;
    }
  }
  return cnt;
}

char *OptArg(int n)
{
  int i;
  i = argindex(n);
  return i>=0 ? g_argv[i] : 0;
}

void OptErr(int n)
{
  int i;
  i = argindex(n);
  if( i>=0 ) errline(i,0,errstream);
}

void OptPrint(void){
  int i;
  int max, len;
  max = 0;
  for(i=0; op[i].label; i++){
    len = lemonStrlen(op[i].label) + 1;
    switch( op[i].type ){
      case OPT_FLAG:
      case OPT_FFLAG:
        break;
      case OPT_INT:
      case OPT_FINT:
        len += 9;       /* length of "<integer>" */
        break;
      case OPT_DBL:
      case OPT_FDBL:
        len += 6;       /* length of "<real>" */
        break;
      case OPT_STR:
      case OPT_FSTR:
        len += 8;       /* length of "<string>" */
        break;
    }
    if( len>max ) max = len;
  }
  for(i=0; op[i].label; i++){
    switch( op[i].type ){
      case OPT_FLAG:
      case OPT_FFLAG:
        fprintf(errstream,"  -%-*s  %s\n",max,op[i].label,op[i].message);
        break;
      case OPT_INT:
      case OPT_FINT:
        fprintf(errstream,"  -%s<integer>%*s  %s\n",op[i].label,
          (int)(max-lemonStrlen(op[i].label)-9),"",op[i].message);
        break;
      case OPT_DBL:
      case OPT_FDBL:
        fprintf(errstream,"  -%s<real>%*s  %s\n",op[i].label,
          (int)(max-lemonStrlen(op[i].label)-6),"",op[i].message);
        break;
      case OPT_STR:
      case OPT_FSTR:
        fprintf(errstream,"  -%s<string>%*s  %s\n",op[i].label,
          (int)(max-lemonStrlen(op[i].label)-8),"",op[i].message);
        break;
    }
  }
}