/*	getargs - command line argument processor for C programs

	(C)	Copyright 1985, Allen I. Holub.  All rights reserved.
	This program may be copied for personal, non-profit use only

	history...

	May 1985	published in Dr. Dobb's Journal #103.
	19 May 85	Transcribed by James R. Van Zandt						*/

#include <stdio.h>
#include <getargs.h>

typedef int (*PFI)();

static char *setarg(argp,linep) ARG *argp; char *linep;

{	/*	set an argument.  argp points at the argument table entry
		corresponding to *linep.  Returns linep, updated to point
		past the argument being set									*/
	++linep;
	switch(argp->type)
		{case INTEGER:	*argp->variable=stoi(&linep); break;
		case BOOLEAN:	*argp->variable=1; break;
		case CHARACTER:	*argp->variable=*linep++; break;
		case STRING:	*(char **)argp->variable=linep; linep=""; break;
		case PROC:		(*(PFI)(argp->variable))(linep); linep=""; break;
		default:
			fprintf(stderr,"INTERNAL ERROR: BAD ARGUMENT TYPE\n"); break;
		}
	return (linep);
}

static ARG *findarg(c,tabp,tabsize) int c,tabsize; ARG *tabp;

{	/*	return pointer to argument table entry corresponding to
		c (or 0 if c isn't in table).							*/
	
	for( ; --tabsize>=0; tabp++) {if(tabp->arg==c) return tabp;}
	return 0;
}

static pr_usage(tabp,tabsize) ARG *tabp; int tabsize;

{	/*	print the argtab in the form:
		-<arg> <errmsg>  (value is <*variable>)					*/

	for(; --tabsize>=0; tabp++)
		{switch(tabp->type)
			{case INTEGER:
				fprintf(stderr,"-%c<num> %-40s (value is ",
					tabp->arg, tabp->errmsg);
				fprintf(stderr,"%-5d)\n",*(tabp->variable));
				break;
			case BOOLEAN:
				fprintf(stderr,"-%c      %-40s (value is ",
					tabp->arg, tabp->errmsg);
				fprintf(stderr,"%-5s)\n",*(tabp->variable)
					?"TRUE":"FALSE");
				break;
			case CHARACTER:
				fprintf(stderr,"-%c<c>   %-40s (value is ",
					tabp->arg,tabp->errmsg);
				fprintf(stderr,"%-5c)\n",*(tabp->variable));
				break;
			case STRING:
				fprintf(stderr,"-%c<str> %-40s (value is ",
					tabp->arg, tabp->errmsg);
				fprintf(stderr,"\"%s\")\n", *(char **)tabp->variable);
				break;
			case PROC:
				fprintf(stderr,"-%c<str> %-40s\n",
					tabp->arg,tabp->errmsg);
				break;
			}
		}
}

#define ERRMSG "Illegal argument \'%c\'.  Legal arguments are:\n\n"

int getargs(argc,argv,tabp,tabsize)
	int argc,tabsize;
	char **argv;
	ARG *tabp;
{	/*	Process command line arguments, stripping all command line
		switches out of argv.  Return a new argc.  If an error is found
		exit(1) is called (getargs won't return) and a usage message
		is printed showing all arguments in the table.				*/

	register int nargc;
	register char **nargv, *p;
	register ARG *argp;

	nargc=1;
	for (nargv=++argv; --argc>0; argv++)
		{if(**argv!='-') {*nargv++=*argv; nargc++;}
		else
			{p=(*argv)+1;
			while(*p)
				{if(argp=findarg(*p,tabp, tabsize)) {p=setarg(argp,p);}
				else
					{fprintf(stderr,ERRMSG,*p);
					pr_usage(tabp,tabsize);
					exit(1);
					}
				}
			}
		}
		return nargc;
}

#define islower(c) ('a'<=(c)&&(c)<='z')
#define toupper(c) (islower(c)?(c)-('a'-'A'):(c))

int stoi(instr)  register char **instr;
{	/*	Convert string to integer.  If string starts with 0x it is
		interpreted as a hex number, else if it starts with a 0 it
		is octal, else it is decimal.  Conversion stops on encountering
		the first character which is not a digit in the indicated
		radix.  *instr is updated to point past the end of the number.	*/

	register int num=0;
	register char *str;
	int sign=1;

	str=*instr;
	while(*str==' ' || *str=='\t' || *str=='\n') {str++;}
	if(*str=='-') {sign=-1; str++;}
	if(*str=='0')
		{++str;
		if(*str=='x' || *str=='X')
			{str++;
			while(	('0'<=*str && *str<='9') ||
					('a'<=*str && *str<='f') ||
					('A'<=*str && *str<='F')	)
				{num=num*16+
					(('0'<=*str && *str<='9') ?
					*str-'0' : 
					toupper(*str)-'A'+10);
				str++;
				}
			}
		else {while('0'<=*str && *str<='7') {num = num*8+ *str++ - '0';}}
		}
	else {while('0'<=*str && *str<='9') {num=num*10+ *str++-'0';}}
	*instr=str;
	return (num*sign);
}