/* Portable vsprintf  by Robert A. Larson <blarson@skat.usc.edu> */

/* Copyright 1989 Robert A. Larson.
 * Distribution in any form is allowed as long as the author
 * retains credit, changes are noted by their author and the
 * copyright message remains intact.  This program comes as-is
 * with no warentee of fitness for any purpouse.
 *
 * Thanks to Doug Gwen, Chris Torek, and others who helped clarify
 * the ansi printf specs.
 *
 * Please send any bug fixes and improvments to blarson@skat.usc.edu .
 * The use of goto is NOT a bug.
 */

/* Feb 7, 1989         blarson         First usenet release */

/* This code implements the vsprintf function, without relying on
 * the existance of _doprint or other system specific code.
 *
 * Define NOVOID if void * is not a supported type.
 *
 * Two compile options are available for efficency:
 *     INTSPRINTF      should be defined if sprintf is int and returns
 *                     the number of chacters formated.
 *     LONGINT         should be defined if sizeof(long) == sizeof(int)
 *
 *     They only make the code smaller and faster, they need not be
 *     defined.
 *
 * UNSIGNEDSPECIAL should be defined if unsigned is treated differently
 * than int in argument passing.  If this is definded, and LONGINT is not,
 * the compiler must support the type unsingned long.
 *
 * Most quirks and bugs of the available sprintf fuction are duplicated,
 * however * in the width and precision fields will work correctly
 * even if sprintf does not support this, as will the n format.
 *
 * Bad format strings, or those with very long width and precision
 * fields (including expanded * fields) will cause undesired results.
 */

#ifdef OSK             /* os9/68k can take advantage of both */
#define LONGINT
#define INTSPRINTF
#endif

/* This must be a typedef not a #define! */
#ifdef NOVOID
typedef char *pointer;
#else
typedef void *pointer;
#endif

#ifdef INTSPRINTF
#define Sprintf(string,format,arg)     (sprintf((string),(format),(arg)))
#else
#define Sprintf(string,format,arg)     (\
       sprintf((string),(format),(arg)),\
       strlen(string)\
)
#endif

#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

typedef int *intp;

int vsprintf(dest, format, args)
char *dest;
register char *format;
va_list args;
{
    register char *dp = dest;
    register char c;
    register char *tp;
    char tempfmt[64];
#ifndef LONGINT
    int longflag;
#endif

    tempfmt[0] = '%';
    while(c = *format++) {
       if(c=='%') {
           tp = &tempfmt[1];
#ifndef LONGINT
           longflag = 0;
#endif
continue_format:
           switch(c = *format++) {
               case 's':
                   *tp++ = c;
                   *tp = '\0';
                   dp += Sprintf(dp, tempfmt, va_arg(args, char *));
                   break;
               case 'u':
               case 'x':
               case 'o':
               case 'X':
#ifdef UNSIGNEDSPECIAL
                   *tp++ = c;
                   *tp = '\0';
#ifndef LONGINT
                   if(longflag)
                       dp += Sprintf(dp, tempfmt, va_arg(args, unsigned long));
                   else
#endif
                       dp += Sprintf(dp, tempfmt, va_arg(args, unsigned));
                   break;
#endif
               case 'd':
               case 'c':
               case 'i':
                   *tp++ = c;
                   *tp = '\0';
#ifndef LONGINT
                   if(longflag)
                       dp += Sprintf(dp, tempfmt, va_arg(args, long));
                   else
#endif
                       dp += Sprintf(dp, tempfmt, va_arg(args, int));
                   break;
               case 'f':
               case 'e':
               case 'E':
               case 'g':
               case 'G':
                   *tp++ = c;
                   *tp = '\0';
                   dp += Sprintf(dp, tempfmt, va_arg(args, double));
                   break;
               case 'p':
                   *tp++ = c;
                   *tp = '\0';
                   dp += Sprintf(dp, tempfmt, va_arg(args, pointer));
                   break;
               case '-':
               case '+':
               case '0':
               case '1':
               case '2':
               case '3':
               case '4':
               case '5':
               case '6':
               case '7':
               case '8':
               case '9':
               case '.':
               case ' ':
               case '#':
               case 'h':
                   *tp++ = c;
                   goto continue_format;
               case 'l':
#ifndef LONGINT
                   longflag = 1;
                   *tp++ = c;
#endif
                   goto continue_format;
               case '*':
                   tp += Sprintf(tp, "%d", va_arg(args, int));
                   goto continue_format;
               case 'n':
                   *va_arg(args, intp) = dp - dest;
                   break;
               case '%':
               default:
                   *dp++ = c;
                   break;
           }
       } else *dp++ = c;
    }
    *dp = '\0';
    return dp - dest;
}