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printf.c

/*
 * Copyright (c) 1989, 1993
 *    The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *    Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>

#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int   conv_escape_str(char *);
static char *conv_escape(char *, int *);
static int   getchr(void);
static double      getdouble(void);
static intmax_t    getintmax(void);
static uintmax_t getuintmax(void);
static char *getstr(void);
static char *mklong(const char *, const char *);
static void      check_conversion(const char *, const char *);

static int  rval;
static char  **gargv;

#define isodigit(c)     ((c) >= '0' && (c) <= '7')
#define octtobin(c)     ((c) - '0')

#include "bltin.h"
#include "system.h"

#define PF(f, func) { \
      switch ((char *)param - (char *)array) { \
      default: \
            (void)printf(f, array[0], array[1], func); \
            break; \
      case sizeof(*param): \
            (void)printf(f, array[0], func); \
            break; \
      case 0: \
            (void)printf(f, func); \
            break; \
      } \
}

int printfcmd(int argc, char *argv[])
{
      char *fmt;
      char *format;
      int ch;

      rval = 0;

      nextopt(nullstr);

      argv = argptr;
      format = *argv;

      if (!format) {
            warnx("usage: printf format [arg ...]");
            goto err;
      }

      gargv = ++argv;

#define SKIP1     "#-+ 0"
#define SKIP2     "*0123456789"
      do {
            /*
             * Basic algorithm is to scan the format string for conversion
             * specifications -- once one is found, find out if the field
             * width or precision is a '*'; if it is, gather up value. 
             * Note, format strings are reused as necessary to use up the
             * provided arguments, arguments of zero/null string are 
             * provided to use up the format string.
             */

            /* find next format specification */
            for (fmt = format; (ch = *fmt++) ;) {
                  char *start;
                  char nextch;
                  int array[2];
                  int *param;

                  if (ch == '\\') {
                        int c_ch;
                        fmt = conv_escape(fmt, &c_ch);
                        ch = c_ch;
                        goto pc;
                  }
                  if (ch != '%' || (*fmt == '%' && (++fmt || 1))) {
pc:
                        putchar(ch);
                        continue;
                  }

                  /* Ok - we've found a format specification,
                     Save its address for a later printf(). */
                  start = fmt - 1;
                  param = array;

                  /* skip to field width */
                  fmt += strspn(fmt, SKIP1);
                  if (*fmt == '*')
                        *param++ = getintmax();

                  /* skip to possible '.', get following precision */
                  fmt += strspn(fmt, SKIP2);
                  if (*fmt == '.')
                        ++fmt;
                  if (*fmt == '*')
                        *param++ = getintmax();

                  fmt += strspn(fmt, SKIP2);

                  ch = *fmt;
                  if (!ch) {
                        warnx("missing format character");
                        goto err;
                  }
                  /* null terminate format string to we can use it
                     as an argument to printf. */
                  nextch = fmt[1];
                  fmt[1] = 0;
                  switch (ch) {

                  case 'b': {
                        int done = conv_escape_str(getstr());
                        char *p = stackblock();
                        *fmt = 's';
                        PF(start, p);
                        /* escape if a \c was encountered */
                        if (done)
                              goto out;
                        *fmt = 'b';
                        break;
                  }
                  case 'c': {
                        int p = getchr();
                        PF(start, p);
                        break;
                  }
                  case 's': {
                        char *p = getstr();
                        PF(start, p);
                        break;
                  }
                  case 'd':
                  case 'i': {
                        intmax_t p = getintmax();
                        char *f = mklong(start, fmt);
                        PF(f, p);
                        break;
                  }
                  case 'o':
                  case 'u':
                  case 'x':
                  case 'X': {
                        uintmax_t p = getuintmax();
                        char *f = mklong(start, fmt);
                        PF(f, p);
                        break;
                  }
                  case 'e':
                  case 'E':
                  case 'f':
                  case 'g':
                  case 'G': {
                        double p = getdouble();
                        PF(start, p);
                        break;
                  }
                  default:
                        warnx("%s: invalid directive", start);
                        goto err;
                  }
                  *++fmt = nextch;
            }
      } while (gargv != argv && *gargv);

out:
      return rval;
err:
      return 1;
}


/*
 * Print SysV echo(1) style escape string 
 *    Halts processing string if a \c escape is encountered.
 */
static int
conv_escape_str(char *str)
{
      int ch;
      char *cp;

      /* convert string into a temporary buffer... */
      STARTSTACKSTR(cp);

      do {
            int c;

            ch = *str++;
            if (ch != '\\')
                  continue;

            ch = *str++;
            if (ch == 'c') {
                  /* \c as in SYSV echo - abort all processing.... */
                  ch = 0x100;
                  continue;
            }

            /* 
             * %b string octal constants are not like those in C.
             * They start with a \0, and are followed by 0, 1, 2, 
             * or 3 octal digits. 
             */
            if (ch == '0') {
                  unsigned char i;
                  i = 3;
                  ch = 0;
                  do {
                        unsigned k = octtobin(*str);
                        if (k > 7)
                              break;
                        str++;
                        ch <<= 3;
                        ch += k;
                  } while (--i);
                  continue;
            }

            /* Finally test for sequences valid in the format string */
            str = conv_escape(str - 1, &c);
            ch = c;
      } while (STPUTC(ch, cp), (char)ch);

      return ch;
}

/*
 * Print "standard" escape characters 
 */
static char *
conv_escape(char *str, int *conv_ch)
{
      int value;
      int ch;

      ch = *str;

      switch (ch) {
      default:
      case 0:
            value = '\\';
            goto out;

      case '0': case '1': case '2': case '3':
      case '4': case '5': case '6': case '7':
            ch = 3;
            value = 0;
            do {
                  value <<= 3;
                  value += octtobin(*str++);
            } while (isodigit(*str) && --ch);
            goto out;

      case '\\':  value = '\\';     break;      /* backslash */
      case 'a':   value = '\a';     break;      /* alert */
      case 'b':   value = '\b';     break;      /* backspace */
      case 'f':   value = '\f';     break;      /* form-feed */
      case 'n':   value = '\n';     break;      /* newline */
      case 'r':   value = '\r';     break;      /* carriage-return */
      case 't':   value = '\t';     break;      /* tab */
      case 'v':   value = '\v';     break;      /* vertical-tab */
      }

      str++;
out:
      *conv_ch = value;
      return str;
}

static char *
mklong(const char *str, const char *ch)
{
      char *copy;
      size_t len; 

      len = ch - str + 3;
      STARTSTACKSTR(copy);
      copy = makestrspace(len, copy);
      memcpy(copy, str, len - 3);
      copy[len - 3] = 'j';
      copy[len - 2] = *ch;
      copy[len - 1] = '\0';
      return (copy);    
}

static int
getchr(void)
{
      int val = 0;

      if (*gargv)
            val = **gargv++;
      return val;
}

static char *
getstr(void)
{
      char *val = nullstr;

      if (*gargv)
            val = *gargv++;
      return val;
}

static intmax_t
getintmax(void)
{
      intmax_t val = 0;
      char *cp, *ep;

      cp = *gargv;
      if (cp == NULL)
            goto out;
      gargv++;

      val = (unsigned char) cp[1];
      if (*cp == '\"' || *cp == '\'')
            goto out;

      errno = 0;
      val = strtoimax(cp, &ep, 0);
      check_conversion(cp, ep);
out:
      return val;
}

static uintmax_t
getuintmax(void)
{
      uintmax_t val = 0;
      char *cp, *ep;

      cp = *gargv;
      if (cp == NULL)
            goto out;
      gargv++;

      val = (unsigned char) cp[1];
      if (*cp == '\"' || *cp == '\'')
            goto out;

      errno = 0;
      val = strtoumax(cp, &ep, 0);
      check_conversion(cp, ep);
out:
      return val;
}

static double
getdouble(void)
{
      double val;
      char *cp, *ep;

      cp = *gargv;
      if (cp == NULL)
            return 0;
      gargv++;

      if (*cp == '\"' || *cp == '\'')
            return (unsigned char) cp[1];

      errno = 0;
      val = strtod(cp, &ep);
      check_conversion(cp, ep);
      return val;
}

static void
check_conversion(const char *s, const char *ep)
{
      if (*ep) {
            if (ep == s)
                  warnx("%s: expected numeric value", s);
            else
                  warnx("%s: not completely converted", s);
            rval = 1;
      } else if (errno == ERANGE) {
            warnx("%s: %s", s, strerror(ERANGE));
            rval = 1;
      }
}

int
echocmd(int argc, char **argv)
{
      int nonl = 0;
      struct output *outs = out1;

      if (!*++argv)
            goto end;
      if (equal(*argv, "-n")) {
            nonl = ~nonl;
            if (!*++argv)
                  goto end;
      }

      do {
            char c;

            nonl += conv_escape_str(*argv);
            outstr(stackblock(), outs);
            if (nonl > 0)
                  break;

            c = ' ';
            if (!*++argv) {
end:
                  if (nonl) {
                        break;
                  }
                  c = '\n';
            }
            outc(c, outs);
      } while (*argv);
      return 0;
}

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