ethereal公司开发的aodv路由协议代码

				/* $Id: glib-util.c,v 1.1 2001/02/01 20:21:18 gram Exp $ */								#include 				#include 												#include 								char*				g_substrdup(const char *s, int start, int len)				{					int s_len, abs_start, abs_len;					char *newstring;													s_len = strlen(s);									if (start < 0) {						abs_start = s_len + start;						if (abs_start < 0) {							return NULL;						}					}					else {						abs_start = start;					}									if (len < 0) {						abs_len = s_len + len + 1 - abs_start;						if (abs_len < 0) {							return NULL;						}					}					else {						abs_len = len;					}													if (abs_start + abs_len > s_len) {						return NULL;					}									newstring = g_strndup(s + abs_start, abs_len + 1);					newstring[abs_len] = 0;									return newstring;				}