コード例 #1
0
ファイル: strings.c プロジェクト: huangjingpei/asterisk
int __ast_str_helper(struct ast_str **buf, ssize_t max_len,
	int append, const char *fmt, va_list ap)
#endif
{
	int res, need;
	int offset = (append && (*buf)->__AST_STR_LEN) ? (*buf)->__AST_STR_USED : 0;
	va_list aq;

	do {
		if (max_len < 0) {
			max_len = (*buf)->__AST_STR_LEN;	/* don't exceed the allocated space */
		}
		/*
		 * Ask vsnprintf how much space we need. Remember that vsnprintf
		 * does not count the final <code>'\\0'</code> so we must add 1.
		 */
		va_copy(aq, ap);
		res = vsnprintf((*buf)->__AST_STR_STR + offset, (*buf)->__AST_STR_LEN - offset, fmt, aq);

		need = res + offset + 1;
		/*
		 * If there is not enough space and we are below the max length,
		 * reallocate the buffer and return a message telling to retry.
		 */
		if (need > (*buf)->__AST_STR_LEN && (max_len == 0 || (*buf)->__AST_STR_LEN < max_len) ) {
			int len = (int)(*buf)->__AST_STR_LEN;
			if (max_len && max_len < need) {	/* truncate as needed */
				need = max_len;
			} else if (max_len == 0) {	/* if unbounded, give more room for next time */
				need += 16 + need / 4;
			}
			if (0) {	/* debugging */
				ast_verbose("extend from %d to %d\n", len, need);
			}
			if (
#if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
					_ast_str_make_space(buf, need, file, lineno, function)
#else
					ast_str_make_space(buf, need)
#endif
				) {
				ast_verbose("failed to extend from %d to %d\n", len, need);
				va_end(aq);
				return AST_DYNSTR_BUILD_FAILED;
			}
			(*buf)->__AST_STR_STR[offset] = '\0';	/* Truncate the partial write. */

			/* Restart va_copy before calling vsnprintf() again. */
			va_end(aq);
			continue;
		}
		va_end(aq);
		break;
	} while (1);
	/* update space used, keep in mind the truncation */
	(*buf)->__AST_STR_USED = (res + offset > (*buf)->__AST_STR_LEN) ? (*buf)->__AST_STR_LEN - 1: res + offset;

	return res;
}
コード例 #2
0
ファイル: strings.c プロジェクト: credativUK/asterisk
int __ast_str_helper(struct ast_str **buf, ssize_t max_len,
	int append, const char *fmt, va_list ap)
#endif
{
	int res;
	int added;
	int need;
	int offset = (append && (*buf)->__AST_STR_LEN) ? (*buf)->__AST_STR_USED : 0;
	va_list aq;

	if (max_len < 0) {
		max_len = (*buf)->__AST_STR_LEN;	/* don't exceed the allocated space */
	}

	do {
		va_copy(aq, ap);
		res = vsnprintf((*buf)->__AST_STR_STR + offset, (*buf)->__AST_STR_LEN - offset, fmt, aq);
		va_end(aq);

		if (res < 0) {
			/*
			 * vsnprintf write to string failed.
			 * I don't think this is possible with a memory buffer.
			 */
			res = AST_DYNSTR_BUILD_FAILED;
			added = 0;
			break;
		}

		/*
		 * vsnprintf returns how much space we used or would need.
		 * Remember that vsnprintf does not count the nil terminator
		 * so we must add 1.
		 */
		added = res;
		need = offset + added + 1;
		if (need <= (*buf)->__AST_STR_LEN
			|| (max_len && max_len <= (*buf)->__AST_STR_LEN)) {
			/*
			 * There was enough room for the string or we are not
			 * allowed to try growing the string buffer.
			 */
			break;
		}

		/* Reallocate the buffer and try again. */
		if (max_len == 0) {
			/* unbounded, give more room for next time */
			need += 16 + need / 4;
		} else if (max_len < need) {
			/* truncate as needed */
			need = max_len;
		}

		if (
#if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
			_ast_str_make_space(buf, need, file, lineno, function)
#else
			ast_str_make_space(buf, need)
#endif
			) {
			ast_log_safe(LOG_VERBOSE, "failed to extend from %d to %d\n",
				(int) (*buf)->__AST_STR_LEN, need);

			res = AST_DYNSTR_BUILD_FAILED;
			break;
		}
	} while (1);

	/* Update space used, keep in mind truncation may be necessary. */
	(*buf)->__AST_STR_USED = ((*buf)->__AST_STR_LEN <= offset + added)
		? (*buf)->__AST_STR_LEN - 1
		: offset + added;

	/* Ensure that the string is terminated. */
	(*buf)->__AST_STR_STR[(*buf)->__AST_STR_USED] = '\0';

	return res;
}