ustringformat.cpp

#include "ustringformat.h"

/* Blatantly stolen from FREEBSD. */

typedef uint64 uintmax_t;
typedef int64 intmax_t;
typedef uint64 u_quad_t;
typedef int64 quad_t;

char* ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
{
  char *p = nbuf;
  *p = '\0';
  do
  {
    *++p = upper ? hex2asciiupper(num % base) : hex2ascii(num % base);
  } while (num /= base);
  if (lenp)
    *lenp = p - nbuf;
  return (p);
}

int kvprintf(char const *fmt, void (*func)(int,void*), void *arg, int radix, va_list ap)
{
#define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
  char nbuf[MAXNBUF];
  char *d;
  const char *p, *percent, *q;
  u_char *up;
  int ch, n;
  uintmax_t num;
  int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
  int cflag, hflag, jflag, tflag, zflag;
  int dwidth, upper;
  char padc;
  int stop = 0, retval = 0;

  num = 0;
  if (!func)
    d = (char *) arg;
  else
    d = NULL;

  if (fmt == NULL)
    fmt = "(fmt null)\n";

  if (radix < 2 || radix > 36)
    radix = 10;

  for (;;)
  {
    padc = ' ';
    width = 0;
    while ((ch = (u_char) *fmt++) != '%' || stop)
    {
      if (ch == '\0')
        return (retval);
      PCHAR(ch);
    }
    percent = fmt - 1;
    qflag = 0;
    lflag = 0;
    ladjust = 0;
    sharpflag = 0;
    neg = 0;
    sign = 0;
    dot = 0;
    dwidth = 0;
    upper = 0;
    cflag = 0;
    hflag = 0;
    jflag = 0;
    tflag = 0;
    zflag = 0;
    reswitch: switch (ch = (u_char) *fmt++)
    {
      case '.':
        dot = 1;
        goto reswitch;
      case '#':
        sharpflag = 1;
        goto reswitch;
      case '+':
        sign = 1;
        goto reswitch;
      case '-':
        ladjust = 1;
        goto reswitch;
      case '%':
        PCHAR(ch)
        ;
        break;
      case '*':
        if (!dot)
        {
          width = va_arg(ap, int);
          if (width < 0)
          {
            ladjust = !ladjust;
            width = -width;
          }
        }
        else
        {
          dwidth = va_arg(ap, int);
        }
        goto reswitch;
      case '0':
        if (!dot)
        {
          padc = '0';
          goto reswitch;
        }
        // fall-through
      case '1':
      case '2':
      case '3':
      case '4':
      case '5':
      case '6':
      case '7':
      case '8':
      case '9':
        for (n = 0;; ++fmt)
        {
          n = n * 10 + ch - '0';
          ch = *fmt;
          if (ch < '0' || ch > '9')
            break;
        }
        if (dot)
          dwidth = n;
        else
          width = n;
        goto reswitch;
      case 'b':
        num = (u_int) va_arg(ap, int);
        p = va_arg(ap, char *);
        for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
          PCHAR(*q--)
        ;

        if (num == 0)
          break;

        for (tmp = 0; *p;)
        {
          n = *p++;
          if (num & (1 << (n - 1)))
          {
            PCHAR(tmp ? ',' : '<');
            for (; (n = *p) > ' '; ++p)
              PCHAR(n);
            tmp = 1;
          }
          else
            for (; *p > ' '; ++p)
              continue;
        }
        if (tmp)
          PCHAR('>')
        ;
        break;
      case 'c':
        PCHAR(va_arg(ap, int))
        ;
        break;
      case 'D':
        up = va_arg(ap, u_char *);
        p = va_arg(ap, char *);
        if (!width)
          width = 16;
        while (width--)
        {
          PCHAR(hex2ascii(*up >> 4));
          PCHAR(hex2ascii(*up & 0x0f));
          up++;
          if (width)
            for (q = p; *q; q++)
              PCHAR(*q);
        }
        break;
      case 'd':
      case 'i':
        base = 10;
        sign = 1;
        goto handle_sign;
      case 'h':
        if (hflag)
        {
          hflag = 0;
          cflag = 1;
        }
        else
          hflag = 1;
        goto reswitch;
      case 'j':
        jflag = 1;
        goto reswitch;
      case 'l':
        if (lflag)
        {
          lflag = 0;
          qflag = 1;
        }
        else
          lflag = 1;
        goto reswitch;
      case 'n':
        if (jflag)
          *(va_arg(ap, intmax_t *)) = retval;
        else if (qflag)
          *(va_arg(ap, quad_t *)) = retval;
        else if (lflag)
          *(va_arg(ap, long *)) = retval;
        else if (zflag)
          *(va_arg(ap, size_t *)) = retval;
        else if (hflag)
          *(va_arg(ap, short *)) = retval;
        else if (cflag)
          *(va_arg(ap, char *)) = retval;
        else
          *(va_arg(ap, int *)) = retval;
        break;
      case 'o':
        base = 8;
        goto handle_nosign;
      case 'p':
        base = 16;
        sharpflag = (width == 0);
        sign = 0;
        num = (uintptr_t) va_arg(ap, void *);
        goto number;
      case 'q':
        qflag = 1;
        goto reswitch;
      case 'r':
        base = radix;
        if (sign)
          goto handle_sign;
        goto handle_nosign;
      case 's':
        p = va_arg(ap, char *);
        if (p == NULL)
          p = "(null)";
        if (!dot)
          n = strlen(p);
        else
          for (n = 0; n < dwidth && p[n]; n++)
            continue;

        width -= n;

        if (!ladjust && width > 0)
          while (width--)
            PCHAR(padc)
        ;
        while (n--)
          PCHAR(*p++)
        ;
        if (ladjust && width > 0)
          while (width--)
            PCHAR(padc)
        ;
        break;
      case 't':
        tflag = 1;
        goto reswitch;
      case 'u':
        base = 10;
        goto handle_nosign;
      case 'X':
        upper = 1;
        // fall-through
      case 'x':
        sharpflag = 1;
        base = 16;
        goto handle_nosign;
      case 'y':
        base = 16;
        sign = 1;
        goto handle_sign;
      case 'z':
        zflag = 1;
        goto reswitch;
        handle_nosign: sign = 0;
        if (jflag)
          num = va_arg(ap, uintmax_t);
        else if (qflag)
          num = va_arg(ap, u_quad_t);
        else if (tflag)
          num = va_arg(ap, ptrdiff_t);
        else if (lflag)
          num = va_arg(ap, u_long);
        else if (zflag)
          num = va_arg(ap, size_t);
        else if (hflag)
          num = (u_short) va_arg(ap, int);
        else if (cflag)
          num = (u_char) va_arg(ap, int);
        else
          num = va_arg(ap, u_int);
        goto number;
        handle_sign: if (jflag)
          num = va_arg(ap, intmax_t);
        else if (qflag)
          num = va_arg(ap, quad_t);
        else if (tflag)
          num = va_arg(ap, ptrdiff_t);
        else if (lflag)
          num = va_arg(ap, long);
        else if (zflag)
          num = va_arg(ap, ssize_t);
        else if (hflag)
          num = (short) va_arg(ap, int);
        else if (cflag)
          num = (char) va_arg(ap, int);
        else
          num = va_arg(ap, int);
        number: if (sign && (intmax_t) num < 0)
        {
          neg = 1;
          num = -(intmax_t) num;
        }
        p = ksprintn(nbuf, num, base, &n, upper);
        tmp = 0;
        if (sharpflag && num != 0)
        {
          if (base == 8)
            tmp++;
          else if (base == 16)
            tmp += 2;
        }
        if (neg)
          tmp++;

        if (!ladjust && padc == '0')
          dwidth = width - tmp;
        width -= tmp + Max(dwidth, n);
        dwidth -= n;
        if (!ladjust)
          while (width-- > 0)
            PCHAR(' ')
        ;
        if (neg)
          PCHAR('-')
        ;
        if (sharpflag && num != 0)
        {
          if (base == 8)
          {
            PCHAR('0');
          }
          else if (base == 16)
          {
            PCHAR('0');
            PCHAR('x');
          }
        }
        while (dwidth-- > 0)
          PCHAR('0')
        ;

        while (*p)
          PCHAR(*p--)
        ;

        if (ladjust)
          while (width-- > 0)
            PCHAR(' ')
        ;

        break;
      default:
        while (percent < fmt)
          PCHAR(*percent++)
        ;
        /*
         * Since we ignore an formatting argument it is no
         * longer safe to obey the remaining formatting
         * arguments as the arguments will no longer match
         * the format specs.
         */
        stop = 1;
        break;
    }
  }
#undef PCHAR
}

void snprintf_func(int ch, void *arg)
{
  snprintf_arg * const info = (snprintf_arg* const ) arg;

  if (info->remain >= 2)
  {
    *info->str++ = ch;
    info->remain--;
  }
}

/*
 * Scaled down version of vsnprintf(3).
 */
int vsnprintf(char *str, size_t size, const char *format, va_list ap)
{
  snprintf_arg info;
  int retval;

  info.str = str;
  info.remain = size;
  retval = kvprintf(format, snprintf_func, &info, 10, ap);
  if (info.remain >= 1)
    *info.str++ = '\0';
  return retval;
}