C 常用自定义函数

1. 字符串拼接

void myStrCat(char* s1,char* s2,char** ret){
	char* r;
	r=(char*)malloc(strlen(s1)+strlen(s2)+1);
	if(!r){
		printf("memory allocate failure\n");
		exit(1);
	}
	strcpy(r,s1);
	strcat(r,s2);
	*ret = r;
        //TODO be carefull free this memory
}

 

2. 缓冲区拷贝

void bufCopy(char* p, int n){
	int N;
	char* bufptr;
	char* buffer;

	buffer = (char*)malloc(sizeof(char)*N);

	while (n > 0){
		int k, rem;
		if(bufptr == &buffer[N]){
			//TODO flush buffer
				;
		}
		rem = N - (bufptr - buffer);
		k = n > rem? rem: n;
		memcpy(bufptr,p,k);
		p += k;
		n -= k;
	}
}