FreeBSD/Linux Kernel Cross Reference
sys/kern/printf.c

     /* 
      * Mach Operating System
      * Copyright (c) 1993 Carnegie Mellon University
      * All Rights Reserved.
      * 
      * Permission to use, copy, modify and distribute this software and its
      * documentation is hereby granted, provided that both the copyright
      * notice and this permission notice appear in all copies of the
      * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     * 
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     * 
     * Carnegie Mellon requests users of this software to return to
     * 
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     * 
     * any improvements or extensions that they make and grant Carnegie Mellon
     * the rights to redistribute these changes.
     */
    /*
     * HISTORY
     * $Log:        printf.c,v $
     * Revision 2.16  93/11/17  17:17:30  dbg
     *      ANSI-fied.  We now have stdarg.h!
     *      Moved iprintf to ddb/db_output.c, since it is only used
     *      by debugging print routines.
     *      [93/10/27            dbg]
     * 
     * Revision 2.15  93/03/09  10:55:12  danner
     *      Lint to quiet GCC.
     *      [93/03/07  13:25:20  af]
     * 
     *      A better, MP-safe sprintf.
     *      [93/03/05            af]
     * 
     * Revision 2.14  93/01/27  09:34:37  danner
     *      printf_init(), sprintf() are void.
     *      [93/01/25            jfriedl]
     * 
     *      Updated copyright.
     *      [93/01/12            berman]
     *      Wrote a version of sprintf() for general use.
     *      [92/03/18            berman]
     * 
     * Revision 2.13  93/01/14  17:35:37  danner
     *      64bit cleanup.  Tuned up doprnt slightly.
     *      [92/12/01            af]
     * 
     * Revision 2.12  92/08/03  17:38:32  jfriedl
     *      removed silly prototypes
     *      [92/08/02            jfriedl]
     * 
     * Revision 2.11  92/05/21  17:14:57  jfriedl
     *      Cleanup to quiet gcc warnings.
     *      Changed PUTC arg of _doprnt, etc. to be VOID (which it is)
     *      [92/05/16            jfriedl]
     * 
     * Revision 2.10  92/04/01  19:33:21  rpd
     *      Renamed gets to safe_gets.
     *      [92/03/31            rpd]
     * 
     * Revision 2.9  91/06/06  17:07:22  jsb
     *      Added gets (derived from boot_gets).
     *      [91/05/14  09:18:50  jsb]
     * 
     * Revision 2.8  91/05/14  16:44:59  mrt
     *      Correcting copyright
     * 
     * Revision 2.7  91/02/05  17:28:14  mrt
     *      Changed to new Mach copyright
     *      [91/02/01  16:15:41  mrt]
     * 
     * Revision 2.6  90/10/25  14:45:18  rwd
     *      Purged uprintf.
     *      [90/10/21            rpd]
     * 
     * Revision 2.5  90/08/27  22:03:08  dbg
     *      Add extra formats to printf: '#- ' prefixes, %z (signed hex),
     *      %r and %n (signed and unsigned, current radix).
     *      [90/08/20            dbg]
     * 
     * Revision 2.4  90/01/11  11:43:44  dbg
     *      De-linted.
     *      [90/01/03            dbg]
     * 
     * Revision 2.3  89/11/29  14:09:06  af
     *      Ooops, a typo.
     *      [89/10/29  09:34:26  af]
     * 
     *      Changed the case for %c to load ints and not chars. Or
     *      else it is byte-order dependent since C passes char as ints.
     *      [89/10/13            af]
     * 
    *      Turned the unused 'file descriptor' field for _doprnt and putchar
    *      into a more useful pointer to an (optional) specialized putchar
    *      routine.  This can be used, for instance, to divert debugging
    *      printouts to some specialized interface or IOP.
    *      [89/10/09            af]
    * 
    * Revision 2.2  89/09/25  11:00:58  rwd
    *      Added case 'X' same as 'x' for now.
    *      [89/09/20            rwd]
    * 
    * Revision 2.1  89/08/03  15:51:14  rwd
    * Created.
    * 
    *  8-Aug-88  David Golub (dbg) at Carnegie-Mellon University
    *      Converted for MACH kernel use.  Removed %r, %R, %b; added %b
    *      from Berkeley's kernel to print bit fields in device registers;
    *      changed to use varargs.
    *
    */
   
   /*
    *  Common code for printf et al.
    *
    *  The calling routine typically takes a variable number of arguments,
    *  and passes the address of the first one.  This implementation
    *  assumes a straightforward, stack implementation, aligned to the
    *  machine's wordsize.  Increasing addresses are assumed to point to
    *  successive arguments (left-to-right), as is the case for a machine
    *  with a downward-growing stack with arguments pushed right-to-left.
    *
    *  To write, for example, fprintf() using this routine, the code
    *
    *      fprintf(fd, format, args)
    *      FILE *fd;
    *      char *format;
    *      {
    *      _doprnt(format, &args, fd);
    *      }
    *
    *  would suffice.  (This example does not handle the fprintf's "return
    *  value" correctly, but who looks at the return value of fprintf
    *  anyway?)
    *
    *  This version implements the following printf features:
    *
    *      %d      decimal conversion
    *      %u      unsigned conversion
    *      %x      hexadecimal conversion
    *      %X      hexadecimal conversion with capital letters
    *      %o      octal conversion
    *      %c      character
    *      %s      string
    *      %m.n    field width, precision
    *      %-m.n   left adjustment
    *      %0m.n   zero-padding
    *      %*.*    width and precision taken from arguments
    *
    *  This version does not implement %f, %e, or %g.  It accepts, but
    *  ignores, an `l' as in %ld, %lo, %lx, and %lu, and therefore will not
    *  work correctly on machines for which sizeof(long) != sizeof(int).
    *  It does not even parse %D, %O, or %U; you should be using %ld, %o and
    *  %lu if you mean long conversion.
    *
    *  As mentioned, this version does not return any reasonable value.
    *
    *  Permission is granted to use, modify, or propagate this code as
    *  long as this notice is incorporated.
    *
    *  Steve Summit 3/25/87
    */
   
   /*
    * Added formats for decoding device registers:
    *
    * printf("reg = %b", regval, "<base><arg>*")
    *
    * where <base> is the output base expressed as a control character:
    * i.e. '\1' gives octal, '\2' gives hex.  Each <arg> is a sequence of
    * characters, the first of which gives the bit number to be inspected
    * (origin 1), and the rest (up to a control character (<= 32)) give the
    * name of the register.  Thus
    *      printf("reg = %b\n", 3, "\1\2BITTWO\1BITONE")
    * would produce
    *      reg = 3<BITTWO,BITONE>
    *
    * If the second character in <arg> is also a control character, it
    * indicates the last bit of a bit field.  In this case, printf will extract
    * bits <1> to <2> and print it.  Characters following the second control
    * character are printed before the bit field.
    *      printf("reg = %b\n", 0xb, "\1\4\3FIELD1=\2BITTWO\1BITONE")
    * would produce
    *      reg = b<FIELD1=2,BITONE>
    */
   /*
    * Added for general use:
    *      #       prefix for alternate format:
    *              0x (0X) for hex
    *              leading 0 for octal
    *      +       print '+' if positive
    *      blank   print ' ' if positive
    *
    *      z       signed hexadecimal
    *      r       signed, 'radix'
    *      n       unsigned, 'radix'
    *
    *      D,U,O,Z same as corresponding lower-case versions
    *              (compatibility)
    */
   
   #include <mach/boolean.h>
   #include <kern/kern_io.h>       /* cnputc, cngetc */
   #include <kern/lock.h>
   #include <kern/strings.h>
   #include <sys/stdarg.h>
   
   #define isdigit(d) ((d) >= '' && (d) <= '9')
   #define Ctod(c) ((c) - '')
   
   #define MAXBUF (sizeof(long int) * 8)            /* enough for binary */
   
   
   void printnum(
           register unsigned long  u,
           register int            base,
           void                    (*putc)( char, void * ),
           void *                  putc_arg)
   {
           char    buf[MAXBUF];    /* build number here */
           register char * p = &buf[MAXBUF-1];
           static char digs[] = "0123456789abcdef";
   
           do {
               *p-- = digs[u % base];
               u /= base;
           } while (u != 0);
   
           while (++p != &buf[MAXBUF])
               (*putc)(*p, putc_arg);
   
   }
   
   boolean_t       _doprnt_truncates = FALSE;
   decl_simple_lock_data(,_doprnt_lock)
   
   void printf_init(void)
   {
           simple_lock_init(&_doprnt_lock);
   }
   
   void _doprnt(
           register const char *fmt,
           va_list         *argp,
                                           /* character output routine */
           void            (*putc)( char, void * ),
           int             radix,          /* default radix - for '%r' */
           void *          putc_arg)
   {
           int             length;
           int             prec;
           boolean_t       ladjust;
           char            padc;
           long            n;
           unsigned long   u;
           int             plus_sign;
           int             sign_char;
           boolean_t       altfmt, truncate;
           int             base;
           register char   c;
   
   #if 0
           /* Make sure that we get *some* printout, no matter what */
           simple_lock(&_doprnt_lock);
   #else
           {
                   register int i = 0;
                   while (i < 1*1024*1024) {
                           if (simple_lock_try(&_doprnt_lock))
                                   break;
                           i++;
                   }
           }
   #endif
   
           while ((c = *fmt) != '\0') {
               if (c != '%') {
                   (*putc)(c, putc_arg);
                   fmt++;
                   continue;
               }
   
               fmt++;
   
               length = 0;
               prec = -1;
               ladjust = FALSE;
               padc = ' ';
               plus_sign = 0;
               sign_char = 0;
               altfmt = FALSE;
   
               while (TRUE) {
                   c = *fmt;
                   if (c == '#') {
                       altfmt = TRUE;
                   }
                   else if (c == '-') {
                       ladjust = TRUE;
                   }
                   else if (c == '+') {
                       plus_sign = '+';
                   }
                   else if (c == ' ') {
                       if (plus_sign == 0)
                           plus_sign = ' ';
                   }
                   else
                       break;
                   fmt++;
               }
   
               if (c == '') {
                   padc = '';
                   c = *++fmt;
               }
   
               if (isdigit(c)) {
                   while(isdigit(c)) {
                       length = 10 * length + Ctod(c);
                       c = *++fmt;
                   }
               }
               else if (c == '*') {
                   length = va_arg(*argp, int);
                   c = *++fmt;
                   if (length < 0) {
                       ladjust = !ladjust;
                       length = -length;
                   }
               }
   
               if (c == '.') {
                   c = *++fmt;
                   if (isdigit(c)) {
                       prec = 0;
                       while(isdigit(c)) {
                           prec = 10 * prec + Ctod(c);
                           c = *++fmt;
                       }
                   }
                   else if (c == '*') {
                       prec = va_arg(*argp, int);
                       c = *++fmt;
                   }
               }
   
               if (c == 'l')
                   c = *++fmt;     /* need it if sizeof(int) < sizeof(long) */
   
               truncate = FALSE;
   
               switch(c) {
                   case 'b':
                   case 'B':
                   {
                       register char *p;
                       boolean_t     any;
                       register int  i;
   
                       u = va_arg(*argp, unsigned long);
                       p = va_arg(*argp, char *);
                       base = *p++;
                       printnum(u, base, putc, putc_arg);
   
                       if (u == 0)
                           break;
   
                       any = FALSE;
                       while ((i = *p++) != '\0') {
                           /* NOTE: The '32' here is because ascii space */
                           if (*p <= 32) {
                               /*
                                * Bit field
                                */
                               register int j;
                               if (any)
                                   (*putc)(',', putc_arg);
                               else {
                                   (*putc)('<', putc_arg);
                                   any = TRUE;
                               }
                               j = *p++;
                               for (; (c = *p) > 32; p++)
                                   (*putc)(c, putc_arg);
                               printnum((unsigned)( (u>>(j-1)) & ((2<<(i-j))-1)),
                                           base, putc, putc_arg);
                           }
                           else if (u & (1<<(i-1))) {
                               if (any)
                                   (*putc)(',', putc_arg);
                               else {
                                   (*putc)('<', putc_arg);
                                   any = TRUE;
                               }
                               for (; (c = *p) > 32; p++)
                                   (*putc)(c, putc_arg);
                           }
                           else {
                               for (; *p > 32; p++)
                                   continue;
                           }
                       }
                       if (any)
                           (*putc)('>', putc_arg);
                       break;
                   }
   
                   case 'c':
                       c = va_arg(*argp, int);
                       (*putc)(c, putc_arg);
                       break;
   
                   case 's':
                   {
                       register char *p;
                       register char *p2;
   
                       if (prec == -1)
                           prec = 0x7fffffff;      /* MAXINT */
   
                       p = va_arg(*argp, char *);
   
                       if (p == (char *)0)
                           p = "";
   
                       if (length > 0 && !ladjust) {
                           n = 0;
                           p2 = p;
   
                           for (; *p != '\0' && n < prec; p++)
                               n++;
   
                           p = p2;
   
                           while (n < length) {
                               (*putc)(' ', putc_arg);
                               n++;
                           }
                       }
   
                       n = 0;
   
                       while (*p != '\0') {
                           if (++n > prec)
                               break;
   
                           (*putc)(*p++, putc_arg);
                       }
   
                       if (n < length && ladjust) {
                           while (n < length) {
                               (*putc)(' ', putc_arg);
                               n++;
                           }
                       }
   
                       break;
                   }
   
                   case 'o':
                       truncate = _doprnt_truncates;
                   case 'O':
                       base = 8;
                       goto print_unsigned;
   
                   case 'd':
                       truncate = _doprnt_truncates;
                   case 'D':
                       base = 10;
                       goto print_signed;
   
                   case 'u':
                       truncate = _doprnt_truncates;
                   case 'U':
                       base = 10;
                       goto print_unsigned;
   
                   case 'x':
                       truncate = _doprnt_truncates;
                   case 'X':
                       base = 16;
                       goto print_unsigned;
   
                   case 'z':
                       truncate = _doprnt_truncates;
                   case 'Z':
                       base = 16;
                       goto print_signed;
   
                   case 'r':
                       truncate = _doprnt_truncates;
                   case 'R':
                       base = radix;
                       goto print_signed;
   
                   case 'n':
                       truncate = _doprnt_truncates;
                   case 'N':
                       base = radix;
                       goto print_unsigned;
   
                   print_signed:
                       n = va_arg(*argp, long);
                       if (n >= 0) {
                           u = n;
                           sign_char = plus_sign;
                       }
                       else {
                           u = -n;
                           sign_char = '-';
                       }
                       goto print_num;
   
                   print_unsigned:
                       u = va_arg(*argp, unsigned long);
                       goto print_num;
   
                   print_num:
                   {
                       char        buf[MAXBUF];    /* build number here */
                       register char *     p = &buf[MAXBUF-1];
                       static char digits[] = "0123456789abcdef";
                       char *prefix = 0;
   
                       if (truncate) u = (long)((int)(u));
   
                       if (u != 0 && altfmt) {
                           if (base == 8)
                               prefix = "";
                           else if (base == 16)
                               prefix = "0x";
                       }
   
                       do {
                           *p-- = digits[u % base];
                           u /= base;
                       } while (u != 0);
   
                       length -= (&buf[MAXBUF-1] - p);
                       if (sign_char)
                           length--;
                       if (prefix)
                           length -= strlen(prefix);
   
                       if (padc == ' ' && !ladjust) {
                           /* blank padding goes before prefix */
                           while (--length >= 0)
                               (*putc)(' ', putc_arg);
                       }
                       if (sign_char)
                           (*putc)(sign_char, putc_arg);
                       if (prefix)
                           while (*prefix)
                               (*putc)(*prefix++, putc_arg);
                       if (padc == '') {
                           /* zero padding goes after sign and prefix */
                           while (--length >= 0)
                               (*putc)('', putc_arg);
                       }
                       while (++p != &buf[MAXBUF])
                           (*putc)(*p, putc_arg);
   
                       if (ladjust) {
                           while (--length >= 0)
                               (*putc)(' ', putc_arg);
                       }
                       break;
                   }
   
                   case '\0':
                       fmt--;
                       break;
   
                   default:
                       (*putc)(c, putc_arg);
               }
           fmt++;
           }
   
           simple_unlock(&_doprnt_lock);
   }
   
   /*
    * Printing (to console)
    */
   
   /*VARARGS1*/
   void printf(const char *fmt, ...)
   {
           va_list listp;
   
           va_start(listp, fmt);
           _doprnt(fmt, &listp, (void (*)(char, void *))cnputc, 16, 0);
           va_end(listp);
   }
   
   /*
    * Printing to generic buffer
    * Returns #bytes printed.
    * Strings are zero-terminated.
    */
   static void
   sputc(
           char    c,
           void    *arg)
   {
           register char   **bufp = (char **) arg;
           register char   *p = *bufp;
           *p++ = c;
           *bufp = p;
   }
   
   int
   sprintf(
           char    *buf,
           const char *fmt,
           ...)
   {
           va_list listp;
           char    *start = buf;
   
           va_start(listp, fmt);
           _doprnt(fmt, &listp, sputc, 16, (void *)&buf);
           va_end(listp);
   
           *buf = 0;
           return (buf - start);
   }
   
   
   void safe_gets(
           char *str,
           int  maxlen)
   {
           register char *lp;
           register int c;
           char *strmax = str + maxlen - 1; /* allow space for trailing 0 */
   
           lp = str;
           for (;;) {
                   c = cngetc();
                   switch (c) {
                   case '\n':
                   case '\r':
                           printf("\n");
                           *lp++ = 0;
                           return;
                           
                   case '\b':
                   case '#':
                   case '\177':
                           if (lp > str) {
                                   printf("\b \b");
                                   lp--;
                           }
                           continue;
   
                   case '@':
                   case 'u'&037:
                           lp = str;
                           printf("\n\r");
                           continue;
   
                   default:
                           if (c >= ' ' && c < '\177') {
                                   if (lp < strmax) {
                                           *lp++ = c;
                                           printf("%c", c);
                                   }
                                   else {
                                           printf("%c", '\007'); /* beep */
                                   }
                           }
                   }
           }
   }

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