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gSoap源码中Alist的使用

typedef struct ALIST_S{    void *memlist;    pthread_mutex_t mutex;}ALIST_T;#define SOAP_MAXALLOCSIZE (0)   // 无限制#define SOAP_CANARY  (0xC0DE)int alist_init(ALIST_T *list);void *soap_malloc(ALIST_T *list, size_t n);void *alist_calloc(ALIST_T *list, size_t n);char *alist_strdup(ALIST_T *list, const char *s);void alist_dealloc(ALIST_T *list, void *p);void alist_uninit(ALIST_T *list);void echo_alist(ALIST_T *list);源码int alist_init(ALIST_T *list){    int iRet = 0;    if (list)    {        list->memlist = NULL;        pthread_mutex_init(&list->mutex, NULL);    }    else    {        iRet = -1;    }    return iRet;}void* alist_calloc(ALIST_T *list, size_t n){     char *p;    if (SOAP_MAXALLOCSIZE > 0 && n > SOAP_MAXALLOCSIZE)        return NULL;    if (n + sizeof(short) < n)        return NULL;    n += sizeof(short);    if (n + ((-(long)n) & (sizeof(void*)-1)) + sizeof(void*) + sizeof(size_t) < n)        return NULL;    n += (-(long)n) & (sizeof(void*)-1); /* align at 4-, 8- or 16-byte boundary by rounding up */       p = (char*)SOAP_CALLOC(n + sizeof(void*) + sizeof(size_t));    if (!p)    {         return NULL;    }    /* set a canary word to detect memory overruns and data corruption */    *(unsigned short*)(p + n - sizeof(unsigned short)) = (unsigned short)SOAP_CANARY;    /* keep chain of alloced cells for destruction */    pthread_mutex_lock(&list->mutex);    *(void**)(p + n) = list->memlist;    *(size_t*)(p + n + sizeof(void*)) = n;    list->memlist = p + n;    PRINT_Y("[%d]List:%x", n, *list);    pthread_mutex_unlock(&list->mutex);    return p;}char *alist_strdup(ALIST_T *list, const char *s){   char *t = NULL;  if (s)  {     size_t n = strlen(s) + 1;    if (n > 0)    { t = (char*)alist_calloc(list, n);      if (t)      { memcpy((void*)t, (const void*)s, n);        t[n - 1] = '\0';      }    }  }  return t;}void alist_dealloc(ALIST_T *list, void *p){  if (list)  {    pthread_mutex_lock(&list->mutex);    if (p)    {        char **q;        for (q = (char **)(void *)&list->memlist; *q; q = *(char***)q)        {            if (*(unsigned short*)(char*)(*q - sizeof(unsigned short)) != (unsigned short)SOAP_CANARY)            {            pthread_mutex_unlock(&list->mutex);                return;            }            if (p == (void*)(*q - *(size_t*)(*q + sizeof(void*))))            {                *q = **(char***)q;                SOAP_FREE(p);                pthread_mutex_unlock(&list->mutex);                return;            }        }    }    else    {        char *q;        while (list->memlist)        {            q = (char*)list->memlist;            if (*(unsigned short*)(char*)(q - sizeof(unsigned short)) != (unsigned short)SOAP_CANARY)            {            pthread_mutex_unlock(&list->mutex);                return;            }            *list = *(void**)q;            q -= *(size_t*)(q + sizeof(void*));            SOAP_FREE(p);        }    }    pthread_mutex_unlock(&list->mutex);  }    return;}void alist_uninit(ALIST_T *list){    if (list)    {        alist_dealloc(list, NULL);        pthread_mutex_destroy(&list->mutex);    }    return ;}void alist_echo(ALIST_T *list){    char *q;    char *tmp;    int index = 0;    if (list)    {    pthread_mutex_lock(&list->mutex);    tmp = list->memlist;    while(tmp)    {        q = (char*)tmp;        if (*(unsigned short*)(char*)(q-sizeof(unsigned short)) != (unsigned short)SOAP_CANARY)        {        pthread_mutex_unlock(&list->mutex);        return;        }        tmp = *(void**)q;        q -= *(size_t*)(q + sizeof(void*));        index ++;    }    pthread_mutex_unlock(&list->mutex);    }    return ;}

特点

1.代码结构简洁
2.可以对多指针的结构体进行统一分配和释放
3.分配和释放添加锁