Initial version of a sscanf() replacement, for those platforms (like
authorTheodore Tso <tytso@mit.edu>
Tue, 12 Sep 1995 00:22:10 +0000 (00:22 +0000)
committerTheodore Tso <tytso@mit.edu>
Tue, 12 Sep 1995 00:22:10 +0000 (00:22 +0000)
Macroloss) that don't have sscanf().

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@6758 dc483132-0cff-0310-8789-dd5450dbe970

src/lib/krb5/posix/ChangeLog
src/lib/krb5/posix/configure.in
src/lib/krb5/posix/sscanf.c [new file with mode: 0644]

index 629c61cf0846067836229bd1832a213faf421c9e..750000f3530dfd0f2661f0bc5c15cabba7217da8 100644 (file)
@@ -1,6 +1,13 @@
+Mon Sep 11 20:20:39 1995  Theodore Y. Ts'o  <tytso@dcl>
+
+       * sscanf.c (sscanf): Initial version of a sscanf() replacement,
+               for those platforms (like Macroloss) that don't have
+               sscanf().
+
 Wed Sep  6 12:00:00 1995  James Mattly  <mattly@fusion.com>
-       * getuid.c:  turn off getuid for metrowerks which has one (which is also
-               a farce), but leave it on for MPW.
+
+       * getuid.c:  turn off getuid for metrowerks which has one (which
+               is also a farce), but leave it on for MPW.
 
 Wed July  5 15:52:31 1995  James Mattly  <mattly@fusion.com>
        * vfprintf.c included <stdio.h>
index 044ccae5e10972945d1afd66ee719a5616e692a1..5756c57ad34c85ccc8d17c716f9d444a9dab5fb4 100644 (file)
@@ -4,7 +4,7 @@ SubdirLibraryRule([${OBJS}])
 V5_SHARED_LIB_OBJS
 AC_CONST
 AC_HEADER_CHECK(paths.h,AC_DEFINE(HAS_PATHS_H))
-AC_REPLACE_FUNCS(vfprintf vsprintf strdup strcasecmp strerror memmove daemon getuid)
+AC_REPLACE_FUNCS(vfprintf vsprintf strdup strcasecmp strerror memmove daemon getuid sscanf)
 AC_FUNC_CHECK(vsyslog, ,[LIBOBJS="[$]LIBOBJS syslog.o"])
 AC_FUNC_CHECK(setsid,AC_DEFINE(HAS_SETSID))
 V5_AC_OUTPUT_MAKEFILE
diff --git a/src/lib/krb5/posix/sscanf.c b/src/lib/krb5/posix/sscanf.c
new file mode 100644 (file)
index 0000000..b7f338c
--- /dev/null
@@ -0,0 +1,784 @@
+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. 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.
+ *
+ *
+ * Copyright (c) 1995 Massachusetts Institute of Technology.
+ *
+ * Modified by Theodore Ts'o from:
+ *
+ *     @(#)vfscanf.c   5.7 (Berkeley) 12/14/92
+ *
+ * To be a stand-alone sscanf function.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <stdarg.h>
+
+#if 0
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+#include "local.h"
+
+#define FLOATING_POINT
+
+#include "floatio.h"
+#endif
+#define        BUF             513     /* Maximum length of numeric string. */
+
+/*
+ * Flags used during conversion.
+ */
+#define        LONG            0x01    /* l: long or double */
+#define        LONGDBL         0x02    /* L: long double; unimplemented */
+#define        SHORT           0x04    /* h: short */
+#define        SUPPRESS        0x08    /* suppress assignment */
+#define        POINTER         0x10    /* weird %p pointer (`fake hex') */
+#define        NOSKIP          0x20    /* do not skip blanks */
+
+/*
+ * The following are used in numeric conversions only:
+ * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
+ * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
+ */
+#define        SIGNOK          0x40    /* +/- is (still) legal */
+#define        NDIGITS         0x80    /* no digits detected */
+
+#define        DPTOK           0x100   /* (float) decimal point is still legal */
+#define        EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
+
+#define        PFXOK           0x100   /* 0x prefix is (still) legal */
+#define        NZDIGITS        0x200   /* no zero digits detected */
+
+/*
+ * Conversion types.
+ */
+#define        CT_CHAR         0       /* %c conversion */
+#define        CT_CCL          1       /* %[...] conversion */
+#define        CT_STRING       2       /* %s conversion */
+#define        CT_INT          3       /* integer, i.e., strtol or strtoul */
+#define        CT_FLOAT        4       /* floating, i.e., strtod */
+
+#define u_char unsigned char
+#define u_long unsigned long
+
+static u_char *__sccl();
+
+/*
+ * sscanf
+ */
+sscanf(char *str, char const *fmt0, ...)
+{
+       va_list ap;
+       register u_char *fmt = (u_char *)fmt0;
+       register int c;         /* character from format, or conversion */
+       register size_t width;  /* field width, or 0 */
+       register char *p;       /* points into all kinds of strings */
+       register int n;         /* handy integer */
+       register int flags;     /* flags as defined above */
+       register char *p0;      /* saves original value of p when necessary */
+       int nassigned;          /* number of fields assigned */
+       int nread;              /* number of characters consumed from string */
+       int base;               /* base argument to strtol/strtoul */
+       u_long (*ccfn)();       /* conversion function (strtol/strtoul) */
+       char ccltab[256];       /* character class table for %[...] */
+       char buf[BUF];          /* buffer for numeric conversions */
+
+       int chars_left;
+       char *char_ptr;
+       
+       /* `basefix' is used to avoid `if' tests in the integer scanner */
+       static short basefix[17] =
+               { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
+
+       chars_left = strlen(str);
+       char_ptr = str;
+       va_start(ap, fmt0);
+       
+       nassigned = 0;
+       nread = 0;
+       base = 0;               /* XXX just to keep gcc happy */
+       ccfn = NULL;            /* XXX just to keep gcc happy */
+       for (;;) {
+               c = *fmt++;
+               if (c == 0) {
+                       va_end(ap);
+                       return (nassigned);
+               }
+               if (isspace(c)) {
+                       for (;;) {
+                               if (chars_left <= 0) {
+                                       va_end(ap);
+                                       return (nassigned);
+                               }
+                               if (!isspace(*char_ptr))
+                                       break;
+                               nread++, chars_left--, char_ptr++;
+                       }
+                       continue;
+               }
+               if (c != '%')
+                       goto literal;
+               width = 0;
+               flags = 0;
+               /*
+                * switch on the format.  continue if done;
+                * break once format type is derived.
+                */
+again:         c = *fmt++;
+               switch (c) {
+               case '%':
+literal:
+                       if (chars_left <= 0)
+                               goto input_failure;
+                       if (*char_ptr != c)
+                               goto match_failure;
+                       chars_left--, char_ptr++;
+                       nread++;
+                       continue;
+
+               case '*':
+                       flags |= SUPPRESS;
+                       goto again;
+               case 'l':
+                       flags |= LONG;
+                       goto again;
+               case 'L':
+                       flags |= LONGDBL;
+                       goto again;
+               case 'h':
+                       flags |= SHORT;
+                       goto again;
+
+               case '0': case '1': case '2': case '3': case '4':
+               case '5': case '6': case '7': case '8': case '9':
+                       width = width * 10 + c - '0';
+                       goto again;
+
+               /*
+                * Conversions.
+                * Those marked `compat' are for 4.[123]BSD compatibility.
+                *
+                * (According to ANSI, E and X formats are supposed
+                * to the same as e and x.  Sorry about that.)
+                */
+               case 'D':       /* compat */
+                       flags |= LONG;
+                       /* FALLTHROUGH */
+               case 'd':
+                       c = CT_INT;
+                       ccfn = (u_long (*)())strtol;
+                       base = 10;
+                       break;
+
+               case 'i':
+                       c = CT_INT;
+                       ccfn = (u_long (*)())strtol;
+                       base = 0;
+                       break;
+
+               case 'O':       /* compat */
+                       flags |= LONG;
+                       /* FALLTHROUGH */
+               case 'o':
+                       c = CT_INT;
+                       ccfn = strtoul;
+                       base = 8;
+                       break;
+
+               case 'u':
+                       c = CT_INT;
+                       ccfn = strtoul;
+                       base = 10;
+                       break;
+
+               case 'X':       /* compat   XXX */
+                       flags |= LONG;
+                       /* FALLTHROUGH */
+               case 'x':
+                       flags |= PFXOK; /* enable 0x prefixing */
+                       c = CT_INT;
+                       ccfn = strtoul;
+                       base = 16;
+                       break;
+
+#ifdef FLOATING_POINT
+               case 'E':       /* compat   XXX */
+               case 'F':       /* compat */
+                       flags |= LONG;
+                       /* FALLTHROUGH */
+               case 'e': case 'f': case 'g':
+                       c = CT_FLOAT;
+                       break;
+#endif
+
+               case 's':
+                       c = CT_STRING;
+                       break;
+
+               case '[':
+                       fmt = __sccl(ccltab, fmt);
+                       flags |= NOSKIP;
+                       c = CT_CCL;
+                       break;
+
+               case 'c':
+                       flags |= NOSKIP;
+                       c = CT_CHAR;
+                       break;
+
+               case 'p':       /* pointer format is like hex */
+                       flags |= POINTER | PFXOK;
+                       c = CT_INT;
+                       ccfn = strtoul;
+                       base = 16;
+                       break;
+
+               case 'n':
+                       if (flags & SUPPRESS)   /* ??? */
+                               continue;
+                       if (flags & SHORT)
+                               *va_arg(ap, short *) = nread;
+                       else if (flags & LONG)
+                               *va_arg(ap, long *) = nread;
+                       else
+                               *va_arg(ap, int *) = nread;
+                       continue;
+
+               /*
+                * Disgusting backwards compatibility hacks.    XXX
+                */
+               case '\0':      /* compat */
+                       va_end(ap);
+                       return (EOF);
+
+               default:        /* compat */
+                       if (isupper(c))
+                               flags |= LONG;
+                       c = CT_INT;
+                       ccfn = (u_long (*)())strtol;
+                       base = 10;
+                       break;
+               }
+
+               /*
+                * We have a conversion that requires input.
+                */
+               if (chars_left <= 0)
+                       goto input_failure;
+
+               /*
+                * Consume leading white space, except for formats
+                * that suppress this.
+                */
+               if ((flags & NOSKIP) == 0) {
+                       while (isspace(*char_ptr)) {
+                               nread++;
+                               if (--chars_left > 0)
+                                       char_ptr++;
+                               else 
+                                       goto input_failure;
+                       }
+                       /*
+                        * Note that there is at least one character in
+                        * the buffer, so conversions that do not set NOSKIP
+                        * ca no longer result in an input failure.
+                        */
+               }
+
+               /*
+                * Do the conversion.
+                */
+               switch (c) {
+
+               case CT_CHAR:
+                       /* scan arbitrary characters (sets NOSKIP) */
+                       if (width == 0)
+                               width = 1;
+                       if (flags & SUPPRESS) {
+                               size_t sum = 0;
+                               for (;;) {
+                                       if ((n = chars_left) < width) {
+                                               sum += n;
+                                               width -= n;
+                                               char_ptr += n;
+                                               if (sum == 0)
+                                                   goto input_failure;
+                                       } else {
+                                               sum += width;
+                                               chars_left -= width;
+                                               char_ptr += width;
+                                               break;
+                                       }
+                               }
+                               nread += sum;
+                       } else {
+                               size_t r;
+                               char *dest;
+
+                               dest = (char *)va_arg(ap, char *);
+                               r = width;
+                               if (r > chars_left)
+                                       r = chars_left;
+                               strncpy(dest, char_ptr, width);
+                               
+                               if (r == 0)
+                                       goto input_failure;
+                               nread += r;
+                               nassigned++;
+                       }
+                       break;
+
+               case CT_CCL:
+                       /* scan a (nonempty) character class (sets NOSKIP) */
+                       if (width == 0)
+                               width = ~0;     /* `infinity' */
+                       /* take only those things in the class */
+                       if (flags & SUPPRESS) {
+                               n = 0;
+                               while (ccltab[*char_ptr]) {
+                                       n++, chars_left--, char_ptr++;
+                                       if (--width == 0)
+                                               break;
+                                       if (chars_left <= 0) {
+                                               if (n == 0)
+                                                       goto input_failure;
+                                               break;
+                                       }
+                               }
+                               if (n == 0)
+                                       goto match_failure;
+                       } else {
+                               p0 = p = va_arg(ap, char *);
+                               while (ccltab[*char_ptr]) {
+                                       chars_left--;
+                                       *p++ = *char_ptr++;
+                                       if (--width == 0)
+                                               break;
+                                       if (chars_left <= 0) {
+                                               if (p == p0)
+                                                       goto input_failure;
+                                               break;
+                                       }
+                               }
+                               n = p - p0;
+                               if (n == 0)
+                                       goto match_failure;
+                               *p = 0;
+                               nassigned++;
+                       }
+                       nread += n;
+                       break;
+
+               case CT_STRING:
+                       /* like CCL, but zero-length string OK, & no NOSKIP */
+                       if (width == 0)
+                               width = ~0;
+                       if (flags & SUPPRESS) {
+                               n = 0;
+                               while (!isspace(*char_ptr)) {
+                                       n++, chars_left--, char_ptr++;
+                                       if (--width == 0)
+                                               break;
+                                       if (chars_left <= 0)
+                                               break;
+                               }
+                               nread += n;
+                       } else {
+                               p0 = p = va_arg(ap, char *);
+                               while (!isspace(*char_ptr)) {
+                                       chars_left--;
+                                       *p++ = *char_ptr++;
+                                       if (--width == 0)
+                                               break;
+                                       if (chars_left <= 0)
+                                               break;
+                               }
+                               *p = 0;
+                               nread += p - p0;
+                               nassigned++;
+                       }
+                       continue;
+
+               case CT_INT:
+                       /* scan an integer as if by strtol/strtoul */
+#ifdef hardway
+                       if (width == 0 || width > sizeof(buf) - 1)
+                               width = sizeof(buf) - 1;
+#else
+                       /* size_t is unsigned, hence this optimisation */
+                       if (--width > sizeof(buf) - 2)
+                               width = sizeof(buf) - 2;
+                       width++;
+#endif
+                       flags |= SIGNOK | NDIGITS | NZDIGITS;
+                       for (p = buf; width; width--) {
+                               c = *char_ptr;
+                               /*
+                                * Switch on the character; `goto ok'
+                                * if we accept it as a part of number.
+                                */
+                               switch (c) {
+
+                               /*
+                                * The digit 0 is always legal, but is
+                                * special.  For %i conversions, if no
+                                * digits (zero or nonzero) have been
+                                * scanned (only signs), we will have
+                                * base==0.  In that case, we should set
+                                * it to 8 and enable 0x prefixing.
+                                * Also, if we have not scanned zero digits
+                                * before this, do not turn off prefixing
+                                * (someone else will turn it off if we
+                                * have scanned any nonzero digits).
+                                */
+                               case '0':
+                                       if (base == 0) {
+                                               base = 8;
+                                               flags |= PFXOK;
+                                       }
+                                       if (flags & NZDIGITS)
+                                           flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
+                                       else
+                                           flags &= ~(SIGNOK|PFXOK|NDIGITS);
+                                       goto ok;
+
+                               /* 1 through 7 always legal */
+                               case '1': case '2': case '3':
+                               case '4': case '5': case '6': case '7':
+                                       base = basefix[base];
+                                       flags &= ~(SIGNOK | PFXOK | NDIGITS);
+                                       goto ok;
+
+                               /* digits 8 and 9 ok iff decimal or hex */
+                               case '8': case '9':
+                                       base = basefix[base];
+                                       if (base <= 8)
+                                               break;  /* not legal here */
+                                       flags &= ~(SIGNOK | PFXOK | NDIGITS);
+                                       goto ok;
+
+                               /* letters ok iff hex */
+                               case 'A': case 'B': case 'C':
+                               case 'D': case 'E': case 'F':
+                               case 'a': case 'b': case 'c':
+                               case 'd': case 'e': case 'f':
+                                       /* no need to fix base here */
+                                       if (base <= 10)
+                                               break;  /* not legal here */
+                                       flags &= ~(SIGNOK | PFXOK | NDIGITS);
+                                       goto ok;
+
+                               /* sign ok only as first character */
+                               case '+': case '-':
+                                       if (flags & SIGNOK) {
+                                               flags &= ~SIGNOK;
+                                               goto ok;
+                                       }
+                                       break;
+
+                               /* x ok iff flag still set & 2nd char */
+                               case 'x': case 'X':
+                                       if (flags & PFXOK && p == buf + 1) {
+                                               base = 16;      /* if %i */
+                                               flags &= ~PFXOK;
+                                               goto ok;
+                                       }
+                                       break;
+                               }
+
+                               /*
+                                * If we got here, c is not a legal character
+                                * for a number.  Stop accumulating digits.
+                                */
+                               break;
+               ok:
+                               /*
+                                * c is legal: store it and look at the next.
+                                */
+                               *p++ = c;
+                               if (--chars_left > 0)
+                                       char_ptr++;
+                               else 
+                                       break;          /* EOF */
+                       }
+                       /*
+                        * If we had only a sign, it is no good; push
+                        * back the sign.  If the number ends in `x',
+                        * it was [sign] '0' 'x', so push back the x
+                        * and treat it as [sign] '0'.
+                        */
+                       if (flags & NDIGITS) {
+                               if (p > buf) {
+                                       chars_left++;
+                                       char_ptr--;
+                                       *char_ptr = *(u_char *)--p;
+                               }
+                               goto match_failure;
+                       }
+                       c = ((u_char *)p)[-1];
+                       if (c == 'x' || c == 'X') {
+                               --p;
+                               chars_left++;
+                               char_ptr--;
+                               *char_ptr = c;
+                       }
+                       if ((flags & SUPPRESS) == 0) {
+                               u_long res;
+
+                               *p = 0;
+                               res = (*ccfn)(buf, (char **)NULL, base);
+                               if (flags & POINTER)
+                                       *va_arg(ap, void **) = (void *)res;
+                               else if (flags & SHORT)
+                                       *va_arg(ap, short *) = res;
+                               else if (flags & LONG)
+                                       *va_arg(ap, long *) = res;
+                               else
+                                       *va_arg(ap, int *) = res;
+                               nassigned++;
+                       }
+                       nread += p - buf;
+                       break;
+
+#ifdef FLOATING_POINT
+               case CT_FLOAT:
+                       /* scan a floating point number as if by strtod */
+#ifdef hardway
+                       if (width == 0 || width > sizeof(buf) - 1)
+                               width = sizeof(buf) - 1;
+#else
+                       /* size_t is unsigned, hence this optimisation */
+                       if (--width > sizeof(buf) - 2)
+                               width = sizeof(buf) - 2;
+                       width++;
+#endif
+                       flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
+                       for (p = buf; width; width--) {
+                               c = *char_ptr;
+                               /*
+                                * This code mimicks the integer conversion
+                                * code, but is much simpler.
+                                */
+                               switch (c) {
+
+                               case '0': case '1': case '2': case '3':
+                               case '4': case '5': case '6': case '7':
+                               case '8': case '9':
+                                       flags &= ~(SIGNOK | NDIGITS);
+                                       goto fok;
+
+                               case '+': case '-':
+                                       if (flags & SIGNOK) {
+                                               flags &= ~SIGNOK;
+                                               goto fok;
+                                       }
+                                       break;
+                               case '.':
+                                       if (flags & DPTOK) {
+                                               flags &= ~(SIGNOK | DPTOK);
+                                               goto fok;
+                                       }
+                                       break;
+                               case 'e': case 'E':
+                                       /* no exponent without some digits */
+                                       if ((flags&(NDIGITS|EXPOK)) == EXPOK) {
+                                               flags =
+                                                   (flags & ~(EXPOK|DPTOK)) |
+                                                   SIGNOK | NDIGITS;
+                                               goto fok;
+                                       }
+                                       break;
+                               }
+                               break;
+               fok:
+                               *p++ = c;
+                               if (--chars_left > 0)
+                                       char_ptr++;
+                               else 
+                                       break;  /* EOF */
+                       }
+                       /*
+                        * If no digits, might be missing exponent digits
+                        * (just give back the exponent) or might be missing
+                        * regular digits, but had sign and/or decimal point.
+                        */
+                       if (flags & NDIGITS) {
+                               if (flags & EXPOK) {
+                                       /* no digits at all */
+                                       while (p > buf) {
+                                               chars_left++;
+                                               char_ptr--;
+                                               *char_ptr = *(u_char *)--p;
+                                       }
+                                       goto match_failure;
+                               }
+                               /* just a bad exponent (e and maybe sign) */
+                               c = *(u_char *)--p;
+                               if (c != 'e' && c != 'E') {
+                                       chars_left++;
+                                       char_ptr--;
+                                       *char_ptr = c; /* sign */
+                                       c = *(u_char *)--p;
+                               }
+                               chars_left++;
+                               char_ptr--;
+                               *char_ptr = c;
+                       }
+                       if ((flags & SUPPRESS) == 0) {
+                               double res;
+
+                               *p = 0;
+                               res = strtod(buf,(char **) NULL);
+                               if (flags & LONG)
+                                       *va_arg(ap, double *) = res;
+                               else
+                                       *va_arg(ap, float *) = res;
+                               nassigned++;
+                       }
+                       nread += p - buf;
+                       break;
+#endif /* FLOATING_POINT */
+               }
+       }
+input_failure:
+       va_end(ap);
+       return (nassigned ? nassigned : -1);
+match_failure:
+       va_end(ap);
+       return (nassigned);
+}
+
+/*
+ * Fill in the given table from the scanset at the given format
+ * (just after `[').  Return a pointer to the character past the
+ * closing `]'.  The table has a 1 wherever characters should be
+ * considered part of the scanset.
+ */
+static u_char *
+__sccl(tab, fmt)
+       register char *tab;
+       register u_char *fmt;
+{
+       register int c, n, v;
+
+       /* first `clear' the whole table */
+       c = *fmt++;             /* first char hat => negated scanset */
+       if (c == '^') {
+               v = 1;          /* default => accept */
+               c = *fmt++;     /* get new first char */
+       } else
+               v = 0;          /* default => reject */
+       /* should probably use memset here */
+       for (n = 0; n < 256; n++)
+               tab[n] = v;
+       if (c == 0)
+               return (fmt - 1);/* format ended before closing ] */
+
+       /*
+        * Now set the entries corresponding to the actual scanset
+        * to the opposite of the above.
+        *
+        * The first character may be ']' (or '-') without being special;
+        * the last character may be '-'.
+        */
+       v = 1 - v;
+       for (;;) {
+               tab[c] = v;             /* take character c */
+doswitch:
+               n = *fmt++;             /* and examine the next */
+               switch (n) {
+
+               case 0:                 /* format ended too soon */
+                       return (fmt - 1);
+
+               case '-':
+                       /*
+                        * A scanset of the form
+                        *      [01+-]
+                        * is defined as `the digit 0, the digit 1,
+                        * the character +, the character -', but
+                        * the effect of a scanset such as
+                        *      [a-zA-Z0-9]
+                        * is implementation defined.  The V7 Unix
+                        * scanf treats `a-z' as `the letters a through
+                        * z', but treats `a-a' as `the letter a, the
+                        * character -, and the letter a'.
+                        *
+                        * For compatibility, the `-' is not considerd
+                        * to define a range if the character following
+                        * it is either a close bracket (required by ANSI)
+                        * or is not numerically greater than the character
+                        * we just stored in the table (c).
+                        */
+                       n = *fmt;
+                       if (n == ']' || n < c) {
+                               c = '-';
+                               break;  /* resume the for(;;) */
+                       }
+                       fmt++;
+                       do {            /* fill in the range */
+                               tab[++c] = v;
+                       } while (c < n);
+#if 1  /* XXX another disgusting compatibility hack */
+                       /*
+                        * Alas, the V7 Unix scanf also treats formats
+                        * such as [a-c-e] as `the letters a through e'.
+                        * This too is permitted by the standard....
+                        */
+                       goto doswitch;
+#else
+                       c = *fmt++;
+                       if (c == 0)
+                               return (fmt - 1);
+                       if (c == ']')
+                               return (fmt);
+#endif
+                       break;
+
+               case ']':               /* end of scanset */
+                       return (fmt);
+
+               default:                /* just another character */
+                       c = n;
+                       break;
+               }
+       }
+       /* NOTREACHED */
+}