تحدي العقول ..البرمجة أم الإبداع ..2

/* * Copyright (c) 2004 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /*- * Copyright (c) 1990, 1993 * 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. */ #include <sys/cdefs.h> #if 0 /* XXX coming soon */ #include <ctype.h> #else static inline int isspace(char c) { return (c == ' ' || c == '\t' || c == '\n' || c == '\12'); } #endif #include <stdarg.h> #include <string.h> #include <sys/param.h> #include <sys/systm.h> #define BUF 32 /* Maximum length of numeric string. */ /* * Flags used during conversion. */ #define LONG 0x01 /* l: long or double */ #define SHORT 0x04 /* h: short */ #define SUPPRESS 0x08 /* *: suppress assignment */ #define POINTER 0x10 /* p: void * (as hex) */ #define NOSKIP 0x20 /* [ or c: do not skip blanks */ #define LONGLONG 0x400 /* ll: long long (+ deprecated q: quad) */ #define SHORTSHORT 0x4000 /* hh: char */ #define UNSIGNED 0x8000 /* %[oupxX] conversions */ /* * 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 /* %[dioupxX] conversion */ static const u_char *__sccl(char *, const u_char *); int sscanf(const char *ibuf, const char *fmt, ...) { va_list ap; int ret; va_start(ap, fmt); ret = vsscanf(ibuf, fmt, ap); va_end(ap); return(ret); } int vsscanf(const char *inp, char const *fmt0, va_list ap) { int inr; const u_char *fmt = (const u_char *)fmt0; int c; /* character from format, or conversion */ size_t width; /* field width, or 0 */ char *p; /* points into all kinds of strings */ int n; /* handy integer */ int flags; /* flags as defined above */ char *p0; /* saves original value of p when necessary */ int nassigned; /* number of fields assigned */ int nconversions; /* number of conversions */ int nread; /* number of characters consumed from fp */ int base; /* base argument to conversion function */ char ccltab[256]; /* character class table for %[...] */ char buf[BUF]; /* buffer for numeric conversions */ /* `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 }; inr = strlen(inp); nassigned = 0; nconversions = 0; nread = 0; base = 0; /* XXX just to keep gcc happy */ for (;;) { c = *fmt++; if (c == 0) return (nassigned); if (isspace(c)) { while (inr > 0 && isspace(*inp)) nread++, inr--, inp++; 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 (inr <= 0) goto input_failure; if (*inp != c) goto match_failure; inr--, inp++; nread++; continue; case '*': flags |= SUPPRESS; goto again; case 'l': if (flags & LONG) { flags &= ~LONG; flags |= LONGLONG; } else flags |= LONG; goto again; case 'q': flags |= LONGLONG; /* not quite */ goto again; case 'h': if (flags & SHORT) { flags &= ~SHORT; flags |= SHORTSHORT; } else 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. */ case 'd': c = CT_INT; base = 10; break; case 'i': c = CT_INT; base = 0; break; case 'o': c = CT_INT; flags |= UNSIGNED; base = 8; break; case 'u': c = CT_INT; flags |= UNSIGNED; base = 10; break; case 'X': case 'x': flags |= PFXOK; /* enable 0x prefixing */ c = CT_INT; flags |= UNSIGNED; base = 16; break; 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; flags |= UNSIGNED; base = 16; break; case 'n': nconversions++; if (flags & SUPPRESS) /* ??? */ continue; if (flags & SHORTSHORT) *va_arg(ap, char *) = nread; else if (flags & SHORT) *va_arg(ap, short *) = nread; else if (flags & LONG) *va_arg(ap, long *) = nread; else if (flags & LONGLONG) *va_arg(ap, long long *) = nread; else *va_arg(ap, int *) = nread; continue; } /* * We have a conversion that requires input. */ if (inr <= 0) goto input_failure; /* * Consume leading white space, except for formats * that suppress this. */ if ((flags & NOSKIP) == 0) { while (isspace(*inp)) { nread++; if (--inr > 0) inp++; else goto input_failure; } /* * Note that there is at least one character in * the buffer, so conversions that do not set NOSKIP * can 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 = inr) < (int)width) { sum += n; width -= n; inp += n; if (sum == 0) goto input_failure; break; } else { sum += width; inr -= width; inp += width; break; } } nread += sum; } else { bcopy(inp, va_arg(ap, char *), width); inr -= width; inp += width; nread += width; nassigned++; } nconversions++; break; case CT_CCL: /* scan a (nonempty) character class (sets NOSKIP) */ if (width == 0) width = (size_t)~0; /* `infinity' */ /* take only those things in the class */ if (flags & SUPPRESS) { n = 0; while (ccltab[(unsigned char)*inp]) { n++, inr--, inp++; if (--width == 0) break; if (inr <= 0) { if (n == 0) goto input_failure; break; } } if (n == 0) goto match_failure; } else { p0 = p = va_arg(ap, char *); while (ccltab[(unsigned char)*inp]) { inr--; *p++ = *inp++; if (--width == 0) break; if (inr <= 0) { if (p == p0) goto input_failure; break; } } n = p - p0; if (n == 0) goto match_failure; *p = 0; nassigned++; } nread += n; nconversions++; break; case CT_STRING: /* like CCL, but zero-length string OK, & no NOSKIP */ if (width == 0) width = (size_t)~0; if (flags & SUPPRESS) { n = 0; while (!isspace(*inp)) { n++, inr--, inp++; if (--width == 0) break; if (inr <= 0) break; } nread += n; } else { p0 = p = va_arg(ap, char *); while (!isspace(*inp)) { inr--; *p++ = *inp++; if (--width == 0) break; if (inr <= 0) break; } *p = 0; nread += p - p0; nassigned++; } nconversions++; continue; case CT_INT: /* scan an integer as if by the conversion function */ #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 = *inp; /* * 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 (--inr > 0) inp++; else break; /* end of input */ } /* * 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) { inp--; inr++; } goto match_failure; } c = ((u_char *)p)[-1]; if (c == 'x' || c == 'X') { --p; inp--; inr++; } if ((flags & SUPPRESS) == 0) { u_quad_t res; *p = 0; if ((flags & UNSIGNED) == 0) res = strtoq(buf, (char **)NULL, base); else res = strtouq(buf, (char **)NULL, base); if (flags & POINTER) *va_arg(ap, void **) = (void *)(uintptr_t)res; else if (flags & SHORTSHORT) *va_arg(ap, char *) = res; else if (flags & SHORT) *va_arg(ap, short *) = res; else if (flags & LONG) *va_arg(ap, long *) = res; else if (flags & LONGLONG) *va_arg(ap, long long *) = res; else *va_arg(ap, int *) = res; nassigned++; } nread += p - buf; nconversions++; break; } } input_failure: return (nconversions != 0 ? nassigned : -1); match_failure: 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 const u_char * __sccl(char *tab, const u_char *fmt) { 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 */ /* XXX: Will not work if sizeof(tab*) > sizeof(char) */ (void) memset(tab, v, 256); 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++; /* fill in the range */ do { tab[++c] = v; } while (c < n); c = n; /* * 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; break; case ']': /* end of scanset */ return (fmt); default: /* just another character */ c = n; break; } } /* NOTREACHED */ }