c、c++字符串匹配
fnmatch(pattern, str, FNM_NOESCAPE)
头文件：https://github.com/gcc-mirror/gcc/blob/master/include/fnmatch.h
源文件：https://github.com/gcc-mirror/gcc/blob/master/libiberty/fnmatch.c
源码解析，转自：https://www.cnblogs.com/oloroso/p/6861576.html
1 /* 2 * Copyright (c) 1989, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Guido van Rossum. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * From FreeBSD fnmatch.c 1.11 37 * $Id: fnmatch.c,v 1.3 1997/08/19 02:34:30 jdp Exp $ 38 */ 39 40 #ifndef _FNMATCH_H_ 41 #define _FNMATCH_H_ 42 43 #define FNM_NOMATCH 1 /* Match failed. */ 44 45 #define FNM_NOESCAPE 0x01 /* 禁用反斜杠进行转义 */ 46 #define FNM_PATHNAME 0x02 /* 斜杠只能被斜杠匹配(即不能被*或者?匹配) */ 47 #define FNM_PERIOD 0x04 /* Period must be matched by period. */ 48 /*如果这个标志设置了，string 里的起始点号必须匹配 pattern 里的点号。 49 一个点号被认为是起始点号，如果它是string 第一个字符，或者如果同时设 50 置了 FNM_PATHNAME，紧跟在斜杠后面的点号。 51 */ 52 #define FNM_LEADING_DIR 0x08 /* Ignore /<tail> after Imatch. */ 53 /*如果这个标志(GNU 扩展)设置了，模式必须匹配跟随在斜杠之后的 string 54 的初始片断。这个标志主要是给 glibc 内部使用并且只在一定条件下实现。 55 即只匹配目录路径部分，不匹配到具体文件名 56 */ 57 #define FNM_CASEFOLD 0x10 /* 模式匹配忽略大小写. */ 58 #define FNM_PREFIX_DIRS 0x20 /* Directory prefixes of pattern match too. */ 59 60 /* Make this compile successfully with "gcc -traditional" */ 61 #ifndef __STDC__ 62 #define const /* empty */ 63 #endif 64 65 int fnmatch(const char *, const char *, int); 66 67 #endif /* !_FNMATCH_H_ */ 68 69 #if defined(LIBC_SCCS) && !defined(lint) 70 static char sccsid[] = "@(#)fnmatch.c 8.2 (Berkeley) 4/16/94"; 71 #endif /* LIBC_SCCS and not lint */ 72 73 /* 74 * 函数fnmatch()，如POSIX 1003.2-1992 B.6节所述。 75 * 将文件名或者目录名与pattern进行比较 76 */ 77 78 #include <ctype.h> 79 #include <string.h> 80 #include <stdio.h> 81 82 // 定义字符串结尾标志 83 #define EOS '\0' 84 85 static const char *rangematch(const char *, char, int); 86 87 int 88 fnmatch(const char *pattern, const char *string, int flags) 89 { 90 const char *stringstart; 91 char c, test; 92 93 for (stringstart = string;;){ 94 // 逐个取匹配字符串中的成分(分为*?和range三种) 95 switch (c = *pattern++) { 96 case EOS: // 没有匹配串的情况 97 // 如果忽略'/'后面的部分，则匹配成功 98 if ((flags & FNM_LEADING_DIR) && *string == '/'){ 99 return (0); 100 } 101 // 如果string也是空串，则匹配成功 102 return (*string == EOS ? 0 : FNM_NOMATCH); 103 case '?': // 匹配单个任意字符 104 // string为空则不能匹配 105 if (*string == EOS){ 106 return (FNM_NOMATCH); 107 } 108 // 判断'/'是否只能由'/'进行匹配 109 if (*string == '/' && (flags & FNM_PATHNAME)){ 110 return (FNM_NOMATCH); 111 } 112 // 判断是否string中的起始'.'必须匹配pattern中的'.'（即'?'不能匹配'.'） 113 if (*string == '.' && (flags & FNM_PERIOD) && 114 (string == stringstart || 115 ((flags & FNM_PATHNAME) && *(string - 1) == '/'))){ 116 return (FNM_NOMATCH); 117 } 118 // 匹配成功则匹配string的下一个字符 119 ++string; 120 break; 121 case '*': // 匹配单个或多个任意字符 122 c = *pattern; 123 /* 多个'*'当做一个 */ 124 while (c == '*'){ 125 c = *++pattern; 126 } 127 // 判断是否需要对'.'进行处理 128 if (*string == '.' && (flags & FNM_PERIOD) && 129 (string == stringstart || 130 ((flags & FNM_PATHNAME) && *(string - 1) == '/'))){ 131 return (FNM_NOMATCH); 132 } 133 134 /* 优化 * 在匹配串结尾或者在 /. 之前的匹配*/ 135 if (c == EOS){ // 在结尾 136 // 判断 * 是否不匹配斜杠 137 if (flags & FNM_PATHNAME){ 138 // 不匹配斜杠，则判断是否忽略'/'之后部分 139 return ((flags & FNM_LEADING_DIR) || 140 ((strchr(string, '/') == NULL) ? 0 : FNM_NOMATCH)); 141 }else{ 142 return (0); 143 } 144 } 145 else if (c == '/' && flags & FNM_PATHNAME) { // 在 /. 之前 146 // 如果string后没有 '/'则匹配失败 147 if ((string = strchr(string, '/')) == NULL){ 148 return (FNM_NOMATCH); 149 } 150 break; 151 } 152 153 /* 非特殊情况下，递归匹配 */ 154 while ((test = *string) != EOS) { 155 // 不对'.'进行特殊处理，进行匹配（则只需判断'/'匹配情况） 156 if (!fnmatch(pattern, string, flags & ~FNM_PERIOD)){ 157 return (0); // 匹配成功 158 } 159 // 对 '/'进行处理（斜杠只匹配斜杠，则匹配失败） 160 if (test == '/' && flags & FNM_PATHNAME){ 161 break; 162 } 163 ++string; 164 } 165 // 返回匹配失败（即*没有匹配成功,'.'和'/'上的匹配没有成功） 166 return (FNM_NOMATCH); 167 case '[': // range 范围匹配 168 if (*string == EOS){ 169 return (FNM_NOMATCH); // 空串匹配失败 170 } 171 if (*string == '/' && flags & FNM_PATHNAME){ 172 return (FNM_NOMATCH); // '/'匹配失败 173 } 174 if ((pattern = 175 rangematch(pattern, *string, flags)) == NULL){ 176 return (FNM_NOMATCH); // 范围匹配失败 177 } 178 ++string; 179 break; 180 case '\\': // 斜杠匹配（判断是否需要转义） 181 if (!(flags & FNM_NOESCAPE)) { 182 if ((c = *pattern++) == EOS) { 183 c = '\\'; 184 --pattern; 185 } 186 } 187 /* 非上述部分，则直接匹配单个字符 */ 188 default: 189 if (c == *string){ 190 ; // 直接匹配上了 191 }else if ((flags & FNM_CASEFOLD) && 192 (tolower((unsigned char)c) == 193 tolower((unsigned char)*string))){ 194 ; // 忽略大小写匹配成功 195 } 196 else if ((flags & FNM_PREFIX_DIRS) && *string == EOS && 197 ((c == '/' && string != stringstart) || 198 (string == stringstart + 1 && *stringstart == '/'))){ 199 return (0); // 匹配成功 200 } 201 else{ 202 return (FNM_NOMATCH); // 匹配失败 203 } 204 string++; 205 break; 206 } 207 } 208 /* NOTREACHED */ 209 } 210 211 // 字符范围匹配 212 // pattern传入如 [a-x]*** 形式的字符串 213 // 匹配失败或匹配到EOS结束(也是失败)，返回NULL 214 // 成功返回匹配串的下一个匹配成分首地址 215 static const char * 216 rangematch(const char *pattern, char test, int flags) 217 { 218 // 此处没有对c进行初始化，可能出问题（栈上变量默认值未定） 219 int negate, ok; 220 char c, c2; 221 222 /* 223 * A bracket expression starting with an unquoted circumflex 224 * character produces unspecified results 225 * 以无引号 ^ 字符开始的方括号表达式，将产生未指定的结果 226 * (IEEE 1003.2-1992,3.13.2). 此实现将其视为 '!',以与正则表达式语法保持一致. 227 * J.T. Conklin (conklin@ngai.kaleida.com) 228 */ 229 // 检测方括号表达式中第一个字符 230 // 如果为!或者^，则对后面匹配的结果取反 231 if ((negate = (*pattern == '!' || *pattern == '^'))){ 232 ++pattern; 233 } 234 235 // 忽略大小写，则转为小写处理 236 if (flags & FNM_CASEFOLD){ 237 test = tolower((unsigned char)test); 238 } 239 // 循环到方括号表达式结束 240 for (ok = 0; (c = *pattern++) != ']';) { 241 // 如果没有禁用转义，获取字符 242 if (c == '\\' && !(flags & FNM_NOESCAPE)){ 243 c = *pattern++; 244 } 245 // 匹配结束 246 if (c == EOS){ 247 return (NULL); 248 } 249 // 忽略大小写，则转为小写 250 if (flags & FNM_CASEFOLD){ 251 c = tolower((unsigned char)c); 252 } 253 // 如果当前匹配项c 的下一个是'-'，则获取'-'后面的一个字符 254 // 例如，匹配串为 [a-x] 当前c为a,则c2为x，表示匹配a-x之间字符 255 if (*pattern == '-' 256 && (c2 = *(pattern + 1)) != EOS && c2 != ']') { 257 pattern += 2; 258 // 判断是否需要转义 259 if (c2 == '\\' && !(flags & FNM_NOESCAPE)){ 260 c2 = *pattern++; 261 } 262 if (c2 == EOS){ 263 return (NULL); 264 } 265 // 判断是否区分大小写 266 if (flags & FNM_CASEFOLD){ 267 c2 = tolower((unsigned char)c2); 268 } 269 // 判断test是否位于 [c,c2]区间 270 if ((unsigned char)c <= (unsigned char)test && 271 (unsigned char)test <= (unsigned char)c2){ 272 ok = 1; 273 } 274 } 275 else if (c == test){ 276 ok = 1; 277 } 278 } 279 // 返回匹配结果 280 return (ok == negate ? NULL : pattern); 281 }
