函数设计原则：
函数应该是无状态的，就是第一次调用和第二次调用是一样的。
getchar返回值是int型。
优秀代码欣赏：Eclipse代码
1 /*******************************************************************************
2 * Copyright (c) 2000, 2005 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 * Kevin Cornell (Rational Software Corporation)
11 *******************************************************************************/
12
13 /* Eclipse Launcher Utility Methods */
14
15 #include "eclipseOS.h"
16 #include "eclipseCommon.h"
17 #include "eclipseUtil.h"
18
19 #include <string.h>
20 #include <stdlib.h>
21 #include <stdio.h>
22 #include <sys/stat.h>
23 #ifdef _WIN32
24 #include <direct.h>
25 #else
26 #include <unistd.h>
27 #include <strings.h>
28 #endif
29
30 #define MAX_LINE_LENGTH 256
31
32 /* Is the given VM J9 */
33 int isJ9VM( _TCHAR* vm )
34 {
35 _TCHAR * ch = NULL, *ch2 = NULL;
36 int res = 0;
37
38 if (vm == NULL)
39 return 0;
40
41 ch = lastDirSeparator( vm );
42 if (isVMLibrary(vm)) {
43 /* a library, call it j9 if the parent dir is j9vm */
44 if(ch == NULL)
45 return 0;
46 ch[0] = 0;
47 ch2 = lastDirSeparator(vm);
48 if(ch2 != NULL) {
49 res = (_tcsicmp(ch2 + 1, _T_ECLIPSE("j9vm")) == 0);
50 }
51 ch[0] = dirSeparator;
52 return res;
53 } else {
54 if (ch == NULL)
55 ch = vm;
56 else
57 ch++;
58 return (_tcsicmp( ch, _T_ECLIPSE("j9") ) == 0);
59 }
60 }
61
62 int checkProvidedVMType( _TCHAR* vm )
63 {
64 _TCHAR* ch = NULL;
65 struct _stat stats;
66
67 if (vm == NULL) return VM_NOTHING;
68
69 if (_tstat(vm, &stats) == 0 && (stats.st_mode & S_IFDIR) != 0) {
70 /* directory */
71 return VM_DIRECTORY;
72 }
73
74 ch = _tcsrchr( vm, _T_ECLIPSE(‘.‘) );
75 if(ch == NULL)
76 return VM_OTHER;
77
78 #ifdef _WIN32
79 if (_tcsicmp(ch, _T_ECLIPSE(".dll")) == 0)
80 #else
81 if ((_tcsicmp(ch, _T_ECLIPSE(".so")) == 0) || (_tcsicmp(ch, _T_ECLIPSE(".jnilib")) == 0) || (_tcsicmp(ch, _T_ECLIPSE(".dylib")) == 0))
82 #endif
83 {
84 return VM_LIBRARY;
85 }
86
87 if (_tcsicmp(ch, _T_ECLIPSE(".ee")) == 0)
88 return VM_EE_PROPS;
89
90 return VM_OTHER;
91 }
92
93 /*
94 * pathList is a pathSeparator separated list of paths, run each through
95 * checkPath and recombine the results.
96 * New memory is always allocated for the result
97 */
98 _TCHAR * checkPathList( _TCHAR* pathList, _TCHAR* programDir, int reverseOrder) {
99 _TCHAR * c1, *c2;
100 _TCHAR * checked, *result;
101 size_t checkedLength = 0, resultLength = 0;
102 size_t bufferLength = _tcslen(pathList);
103
104 result = malloc(bufferLength * sizeof(_TCHAR));
105 c1 = pathList;
106 while (c1 != NULL && *c1 != _T_ECLIPSE(‘\0‘))
107 {
108 c2 = _tcschr(c1, pathSeparator);
109 if (c2 != NULL)
110 *c2 = 0;
111
112 checked = checkPath(c1, programDir, reverseOrder);
113 checkedLength = _tcslen(checked);
114 if (resultLength + checkedLength + 1> bufferLength) {
115 bufferLength += checkedLength + 1;
116 result = realloc(result, bufferLength * sizeof(_TCHAR));
117 }
118
119 if(resultLength > 0) {
120 result[resultLength++] = pathSeparator;
121 result[resultLength] = _T_ECLIPSE(‘\0‘);
122 }
123 _tcscpy(result + resultLength, checked);
124 resultLength += checkedLength;
125
126 if(checked != c1)
127 free(checked);
128 if(c2 != NULL)
129 *(c2++) = pathSeparator;
130 c1 = c2;
131 }
132
133 return result;
134 }
135
136 _TCHAR * concatStrings(_TCHAR**strs) {
137 return concatPaths(strs, 0);
138 }
139
140 _TCHAR * concatPaths(_TCHAR** strs, _TCHAR separator) {
141 _TCHAR separatorString[] = { separator, 0 };
142 _TCHAR * result;
143 int i = -1;
144 size_t length = 0;
145 /* first count how large a buffer we need */
146 while (strs[++i] != NULL) {
147 length += _tcslen(strs[i]) + (separator != 0 ? 1 : 0);
148 }
149
150 result = malloc((length + 1) * sizeof(_TCHAR));
151 result[0] = 0;
152 i = -1;
153 while (strs[++i] != NULL) {
154 result = _tcscat(result, strs[i]);
155 if (separator != 0)
156 result = _tcscat(result, separatorString);
157 }
158 return result;
159 }
160
161 /*
162 * buffer contains a pathSeparator separated list of paths, check
163 * that it contains all the paths given. Each path is expected to be
164 * terminated with a pathSeparator character.
165 */
166 int containsPaths(_TCHAR * str, _TCHAR** paths) {
167 _TCHAR * buffer;
168 _TCHAR * c;
169 int i;
170
171 /* terminate the string with a pathSeparator */
172 buffer = malloc((_tcslen(str) + 2) * sizeof(_TCHAR));
173 _stprintf(buffer, _T_ECLIPSE("%s%c"), str, pathSeparator);
174
175 for (i = 0; paths[i] != NULL; i++) {
176 c = _tcsstr(buffer, paths[i]);
177 if ( c == NULL || !(c == buffer || *(c - 1) == pathSeparator))
178 {
179 /* entry not found */
180 free(buffer);
181 return 0;
182 }
183 }
184 free(buffer);
185 return 1;
186 }
187
188 int isVMLibrary( _TCHAR* vm )
189 {
190 _TCHAR *ch = NULL;
191 if (vm == NULL) return 0;
192 ch = _tcsrchr( vm, ‘.‘ );
193 if(ch == NULL)
194 return 0;
195 #ifdef _WIN32
196 return (_tcsicmp(ch, _T_ECLIPSE(".dll")) == 0);
197 #else
198 return (_tcsicmp(ch, _T_ECLIPSE(".so")) == 0) || (_tcsicmp(ch, _T_ECLIPSE(".jnilib")) == 0) || (_tcsicmp(ch, _T_ECLIPSE(".dylib")) == 0);
199 #endif
200 }
201
202 #ifdef AIX
203
204 #include <sys/types.h>
205 #include <time.h>
206
207 /* Return the JVM version in the format x.x.x
208 */
209 char* getVMVersion( char *vmPath )
210 {
211 char cmd[MAX_LINE_LENGTH];
212 char lineString[MAX_LINE_LENGTH];
213 char* firstChar;
214 char fileName[MAX_LINE_LENGTH];
215 time_t curTime;
216 FILE* fp;
217 int numChars = 0;
218 char* version = NULL;
219
220 /* Define a unique filename for the java output. */
221 (void) time(&curTime);
222 (void) sprintf(fileName, "/tmp/tmp%ld.txt", curTime);
223
224 /* Write java -version output to a temp file */
225 (void) sprintf(cmd,"%s -version 2> %s", vmPath, fileName);
226 (void) system(cmd);
227
228 fp = fopen(fileName, "r");
229 if (fp != NULL)
230 {
231 /* Read java -version output from a temp file */
232 if (fgets(lineString, MAX_LINE_LENGTH, fp) == NULL)
233 lineString[0] = ‘\0‘;
234 fclose(fp);
235 unlink(fileName);
236
237 /* Extract version number */
238 firstChar = (char *) (strchr(lineString, ‘"‘) + 1);
239 if (firstChar != NULL)
240 numChars = (int) (strrchr(lineString, ‘"‘) - firstChar);
241
242 /* Allocate a buffer and copy the version string into it. */
243 if (numChars > 0)
244 {
245 version = malloc( numChars + 1 );
246 strncpy(version, firstChar, numChars);
247 version[numChars] = ‘\0‘;
248 }
249 }
250
251 return version;
252 }
253
254 /* Compare JVM Versions of the form "x.x.x..."
255 *
256 * Returns -1 if ver1 < ver2
257 * Returns 0 if ver1 = ver2
258 * Returns 1 if ver1 > ver2
259 */
260 int versionCmp(char *ver1, char *ver2)
261 {
262 char* dot1;
263 char* dot2;
264 int num1;
265 int num2;
266
267 dot1 = strchr(ver1, ‘.‘);
268 dot2 = strchr(ver2, ‘.‘);
269
270 num1 = atoi(ver1);
271 num2 = atoi(ver2);
272
273 if (num1 > num2)
274 return 1;
275
276 if (num1 < num2)
277 return -1;
278
279 if (dot1 && !dot2) /* x.y > x */
280 return 1;
281
282 if (!dot1 && dot2) /* x < x.y */
283 return -1;
284
285 if (!dot1 && !dot2) /* x == x */
286 return 0;
287
288 return versionCmp((char*)(dot1 + 1), (char*)(dot2 + 1) );
289 }
290 #endif /* AIX */
小结：
原文地址：https://www.cnblogs.com/wanmeishenghuo/p/9563272.html
时间： 2024-10-31 16:04:32