/* snprintf.c - Formatted, length-limited print to a string */

#include <afs/param.h>
#if defined(AFS_OSF20_ENV) && !defined(AFS_DUX50_ENV) || defined(AFS_AIX32_ENV) || (defined(AFS_SUN55_ENV) && !defined(AFS_SUN56_ENV))
#include <sys/types.h>
#include <stdarg.h>
#include <stdio.h>
#include <ctype.h>
#include <netinet/in.h>
#include <netdb.h>
#if defined(AFS_AIX32_ENV) || defined(AFS_SUN55_ENV)
#include <sys/socket.h>
#endif

#define MAXPREC 100

/* Generate an ASCII representation of an integer <val>, as follows:
 * <base> indicates the base to be used (2-36)
 * <uc> is nonzero if letter digits should be uppercase
 * <prec> is the minimum number of digits
 * The resulting number is stored in <buf>, which must be long enough
 * to receive it.  The minimum length is <prec> or ceil(log{base}(val)),
 * whichever is larger, plus room for a trailing NUL.
 */
static void mkint(char *buf, unsigned long val, int base, int uc, int prec)
{
  int len = 0, dig, i;

  while (val) {
    dig = val % base;
    val = (val - dig) / base;
    if (dig < 10)  dig = dig + '0';
    else if (uc) dig = dig + 'A' - 10;
    else         dig = dig + 'a' - 10;
    buf[len++] = dig;
  }
  while (len < prec) buf[len++] = '0';
  for (i = 0; i < (len + 1) / 2; i++) {
    dig = buf[i];
    buf[i] = buf[len - i - 1];
    buf[len - i - 1] = dig;
  }
  buf[len] = 0;
}


/* This function is a mostly-complete implementation of snprintf,
 * with the following features:
 *
 *   - Actually obeys the length limit, which (unfortunately) many
 *     implementations of snprintf do not.
 *  
 *   - Supports all the standard format specifiers for integers
 *     (d, i, o, u, x, X), floating-point values (f, e, E, g, G),
 *     and strings and characters (c, s, %), plus a few unusual
 *     but useful ones described below.
 *  
 *   - Supports all the standard flags (-, 0, +, space, #).  These
 *     flags are ignored if used when they are not appropriate.
 *  
 *   - Supports the standard size modifiers for short (h), long (h),
 *     and double (L) arguments.  These modifiers are ignored if used
 *     when they are not appropriate.
 *  
 *   - Supports minimum field width and precision, where appropriate,
 *     including the use of '*' to specify a value given as an argument
 *     instead of in the format string.  There is a maximum precision
 *     of 100 digits.
 *  
 *   - At present, the 'p' specifier for printing pointers is not
 *     implemented, because it is inherently non-portable and thus
 *     can be implemented correctly only by the compiler's run-time
 *     library.
 *
 *   - Floating-point specifier (%e, %f, %g) are implemented by
 *     calling the standard sprintf, and thus may be unsafe.
 *  
 *   - The '%...$' notation is used primarily when the format string
 *     is specified by the user, who knows but cannot change the order
 *     of the arguments.  Such usage is inherently dangerous and
 *     insecure; thus, it is not supported.
 *  
 * The custom format specifier '%I' is supported.  This specifier
 * takes as its argument an unsigned long integer containing an
 * IPv4 address in network byte order.  The address is rendered
 * either as a hostname or as a dotted quad, as follows:
 *  
 *   - If precision is nonzero or unspecified, a hostname lookup
 *     is attempted; if it is successful, the hostname is printed.
 *     If the hostname lookup fails, the address is printed in
 *     dotted-quad notation.
 *  
 *   - If precision is explicitly specified as 0, then the hostname
 *     lookup is skipped, and dotted-quad notation is always used.
 *  
 *   - If a hostname is to be printed:
 *     + The precision controls the maximum number of characters
 *       printed, as with %s.
 *     + If the '#' flag is specified, any letters in the hostname
 *       will be forced to lower case before printing.
 *     + If the '+' flag is specified, any letters in the hostname
 *       will be forced to upper case before printing.  If both
 *       '#' and '+' are given, the '+' flag will be ignored.
 *     + The '0' and ' ' flags have no effect.
 *  
 *   - If a dotted quad is to be printed:
 *     + The precision has no effect; dotted quads are always
 *       7 to 12 characters in length, depending on the value
 *       to be printed and the format flags used.
 *     + If the '0' flag is given, each field (byte) of the address
 *       will be padded with '0' on the left to three digits.
 *     + If the ' ' flag is given, each field (byte) of the address
 *       will be padded with spaces on the left to three digits.  If
 *       both '0' and ' ' are given, the ' ' flag will be ignored.
 *     + The '#' and '+' flags have no effect.
 */
static void vsnprintf(char *p, unsigned int avail, char *fmt, va_list ap)
{
  unsigned int width, precision, haveprec, len;
  int ljust, plsign, spsign, altform, zfill;
  int hflag, lflag, count, *countp, j;
  char *x, *y, xbuf[MAXPREC + 21], fbuf[20];
  struct hostent *he;
  struct in_addr ia;
  unsigned long UVAL;
  long SVAL, *lcountp;
  double FVAL;
  short *hcountp;

  count = 0;
  avail--;
  while (*fmt && avail) {
    if (*fmt != '%') {
      *p++ = *fmt++;
      avail--;
      count++;
      continue;
    }

    /** Found a format specifier **/
    ljust = plsign = spsign = altform = zfill = 0;
    width = precision = haveprec = 0;
    hflag = lflag = 0;
    fmt++;

    /* parse format flags */
    while (*fmt) {
      switch (*fmt) {
        case '-': ljust   = 1; fmt++; continue;      /* left justify */
        case '+': plsign  = 1; fmt++; continue;      /* use + or - */
        case ' ': spsign  = 1; fmt++; continue;      /* use space or - */
        case '#': altform = 1; fmt++; continue;      /* alternate form */
        case '0': zfill   = 1; fmt++; continue;      /* pad with 0 */
        default: break;
      }
      break;
    }

    /* parse minimum width */
    if (*fmt == '*') {
      width = va_arg(ap, int);
      fmt++;
    } else while (isdigit(*fmt)) {
      width = (width * 10) + (*fmt - '0');
      fmt++;
    }

    /* parse precision */
    if (*fmt == '.') {
      fmt++;
      haveprec = 1;
      if (*fmt == '*') {
        precision = va_arg(ap, int);
        fmt++;
      } else while (isdigit(*fmt)) {
        precision = (precision * 10) + (*fmt - '0');
        fmt++;
      }
    }

    /* parse size flags */
    while (*fmt) {
      switch (*fmt) {
        case 'h': hflag   = 1; fmt++; continue;      /* short argument */
        case 'l': lflag   = 1; fmt++; continue;      /* long argument */
        default: break;
      }
      break;
    }

    /* parse format specifier */
    if (!*fmt) break;
    switch (*fmt++) {
      case 'e':
      case 'E':
      case 'f':
      case 'g':
      case 'G':
        FVAL = va_arg(ap, double);
        sprintf(fbuf, "%%%s%s.*L%c", plsign ? "+" : (spsign ? " " : ""),
                altform ? "#" : "", fmt[-1]);
        if (!haveprec) precision = 6;
        if (precision > MAXPREC) precision = MAXPREC;
        sprintf(xbuf, fbuf, precision, FVAL);
        x = xbuf;
        len = strlen(x);
        break;

      case 'i': 
      case 'd': /* signed decimal integer */
        if      (lflag) SVAL = va_arg(ap, long);
        else if (hflag) SVAL = va_arg(ap, short);
        else            SVAL = va_arg(ap, int);
        UVAL = (SVAL < 0) ? -SVAL : SVAL;

        if (SVAL < 0)    xbuf[0] = '-';
        else if (plsign) xbuf[0] = '+';
        else if (spsign) xbuf[0] = ' ';
        else             xbuf[0] = 0;

        if (!haveprec) {
          if (zfill && !ljust) precision = width - !!xbuf[0];
          else precision = 1;
          if (precision < 1 + !!xbuf[0]) precision = 1 + !!xbuf[0];
        }
        if (precision > MAXPREC) precision = MAXPREC;

        mkint(xbuf + 1, UVAL, 10, 0, precision);
        x = xbuf + !xbuf[0];
        len = strlen(x);
        break;


      case 'o': /* unsigned octal integer */
        if      (lflag) UVAL = va_arg(ap, unsigned long);
        else if (hflag) UVAL = va_arg(ap, unsigned short);
        else            UVAL = va_arg(ap, unsigned int);

        xbuf[0] = '0';

        if (!haveprec) {
          if (zfill && !ljust) precision = width;
          else precision = 1;
        }
        if (precision > MAXPREC) precision = MAXPREC;

        mkint(xbuf + 1, UVAL, 8, 0, precision);
        x = xbuf + (xbuf[1] == '0' || !altform);
        len = strlen(x);
        break;

      case 'u': /* unsigned decimal integer */
        if      (lflag) UVAL = va_arg(ap, unsigned long);
        else if (hflag) UVAL = va_arg(ap, unsigned short);
        else            UVAL = va_arg(ap, unsigned int);

        if (!haveprec) {
          if (zfill && !ljust) precision = width;
          else precision = 1;
        }
        if (precision > MAXPREC) precision = MAXPREC;

        mkint(xbuf, UVAL, 10, 0, precision);
        x = xbuf;
        len = strlen(x);
        break;

      case 'x': 
      case 'X': /* unsigned hexadecimal integer */
        if      (lflag) UVAL = va_arg(ap, unsigned long);
        else if (hflag) UVAL = va_arg(ap, unsigned short);
        else            UVAL = va_arg(ap, unsigned int);

        xbuf[0] = '0';
        xbuf[1] = 'x';

        if (!haveprec) {
          if (zfill && !ljust) precision = width;
          else precision = 1;
        }
        if (precision > MAXPREC) precision = MAXPREC;

        mkint(xbuf + 2, UVAL, 16, 0, precision);
        x = xbuf + ((altform && UVAL) ? 0 : 2);
        len = strlen(x);
        break;

      case '%': /* literal % */
        xbuf[0] = '%';
        xbuf[1] = 0;
        x = xbuf;
        len = 1;
        break;

      case 'c': /* character */
        xbuf[0] = va_arg(ap, int);
        xbuf[1] = 0;
        x = xbuf;
        len = 1;
        break;

      case 's': /* string */
        x = va_arg(ap, char *);
        if (!x) x = "<null>";
        len = strlen(x);
        if (haveprec && precision < len) len = precision;
        break;

      case 'I': /* IP address:
         * value is provided as a network-order unsigned long integer
         * precision specifies max hostname length, as for %s
         * if precision is explicitly 0, no hostname lookup is done
         * if 0fill specified, IPaddr fields are 0-filled to 3 digits
         * if spsign specified, IPaddr fields are space-filled to 3 digits
         */
        UVAL = va_arg(ap, unsigned long);
        ia.s_addr = UVAL;
        if (haveprec && !precision) he = 0;
        else he = gethostbyaddr((char *)&ia, 4, AF_INET);
        if (he) {
          x = he->h_name;
          len = strlen(x);
          if (haveprec && precision < len) len = precision;
          if (altform)
            for (y = x; *y; y++) if (isupper(*y)) *y = tolower(*y);
          else if (plsign)
            for (y = x; *y; y++) if (islower(*y)) *y = toupper(*y);
        } else {
          UVAL = ntohl(UVAL);
          if      (zfill)  x = "%03u.%03u.%03u.%03u";
          else if (spsign) x = "%3u.%3u.%3u.%3u";
          else             x = "%u.%u.%u.%u";
          sprintf(xbuf, x,
                  (UVAL & 0xff000000) >> 24, (UVAL & 0x00ff0000) >> 16,
                  (UVAL & 0x0000ff00) >> 8,  (UVAL & 0x000000ff));
          x = xbuf;
          len = strlen(xbuf);
        }
        break;

      case 'n': /* report count so far */
        if (lflag) {
          lcountp = va_arg(ap, long *);
          *lcountp = count;
        } else if (hflag) {
          hcountp = va_arg(ap, short *);
          *hcountp = count;
        } else {
          countp = va_arg(ap, int *);
          *countp = count;
        }
        continue;

      default: /* unknown specifier */
        continue;
    }

    /* render the results */
    if (len > avail)   len = avail;
    if (!width)        width = len;
    if (width > avail) width = avail;
    j = width - len;
    if (j > 0) {
      avail -= j;
      count += j;
    }

    if (!ljust) while (j-- > 0) *p++ = ' ';

    strncpy(p, x, len);
    avail -= len;
    count += len;
    p += len;

    if (ljust) while (j-- > 0) *p++ = ' ';
  }
  *p = 0;
}


void snprintf(char *p, unsigned int avail, char *fmt, ...)
{
  va_list ap;

  va_start(ap, fmt);
  vsnprintf(p, avail, fmt, ap);
  va_end(ap);
}
#endif /* AFS_OSF20_ENV || AFS_AIX32_ENV */