如何正确使用和免费的ASN1C sequence_of

How to correctly use and free asn1c SEQUENCE_OF?

本文关键字：ASN1C sequence of 免费 何正确      更新时间：2023-10-16

我正在为许多项目使用asn1c lib，但是我从未找到如何使用SEQUENCE_OF的免费成员。因此，我总是将其设置为nullptr，当我使用Valgrind时，(当然(我的列表成员在包含列表的元素上使用ASN_STRUCT_FREE时没有释放。

所以我的问题是我如何使用该免费成员？

这是一个简单的示例，说明我如何使用ASN1C使用列表。

ListItem_t *li = nullptr;
StructWList_t swl;
swl.list.count = 0;
swl.list.size = 0;
swl.list.free = nullptr; // How can I feed it properly?
swl.list.array = reinterpret_cast<ListItem_t**>(calloc(1, sizeof *swl.list.array));
for(int i = 0 ; i < 5 ; i++)
{
    li = reinterpret_cast<ListItem_t*>(calloc(1, sizeof *li));
    *li = i;
    // Valgrind says that the calloc below is definitly lost
    swl.list.array[i] = reinterpret_cast<ListItem_t*>(calloc(1, sizeof *swl.list.array[i]));
    ASN_SEQUENCE_ADD(&swl, li);
}
...
ASN_STRUCT_FREE(ASN_DEF_StructWList, &swl);

有人知道如何正确喂食吗？

编辑

我的ASN1C版本是AUR中Git存储库的V0.9.29(在Archlinux上(。

上述ASN.1如下：

Example 
DEFINITIONS AUTOMATIC TAGS ::= 
BEGIN 
StructWList ::= SEQUENCE OF ListItem 
ListItem ::= INTEGER 
END

预先感谢

emilien 

// Valgrind says that the calloc below is definitly lost
swl.list.array[i] = reinterpret_cast<ListItem_t*>(calloc(1, sizeof *swl.list.array[i]));
ASN_SEQUENCE_ADD(&swl, li);

ASN_SEQUENCE_ADD将覆盖您存储在上一行上的指针。您应该手动将其作为第一行中的手动存储，或者致电ASN_SEQUENCE_ADD，但不要同时存放。

您也应该完全初始化swl，因为它包含更多成员(_asn_ctx(并使用ASN_STRUCT_FREE_CONTENTS_ONLY作为swl分配在堆栈上，无法释放。

--- main.cpp.orig   2019-05-07 20:49:25.880336931 +0300
+++ main.cpp    2019-05-07 20:59:10.192431926 +0300
@@ -3,7 +3,7 @@
 int main()
 {
    ListItem_t *li = nullptr;
-   StructWList_t swl;
+   StructWList_t swl = {0};
    swl.list.count = 0;
    swl.list.size = 0;
@@ -15,8 +15,8 @@
        li = reinterpret_cast<ListItem_t*>(calloc(1, sizeof *li));
        *li = i;
        // Valgrind says that the calloc below is definitly lost
-       swl.list.array[i] = reinterpret_cast<ListItem_t*>(calloc(1, sizeof *swl.list.array[i]));
+       //swl.list.array[i] = reinterpret_cast<ListItem_t*>(calloc(1, sizeof *swl.list.array[i]));
        ASN_SEQUENCE_ADD(&swl, li);
    }
-   ASN_STRUCT_FREE(ASN_DEF_StructWList, &swl);
+   ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_StructWList, &swl);
 }

用g++ -Wall -I. -ggdb -O0 -o test main.cpp libasncodec.a

编译 
valgrind --tool=memcheck ./test 
==29555== Memcheck, a memory error detector
==29555== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==29555== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==29555== Command: ./test
==29555== 
==29555== 
==29555== HEAP SUMMARY:
==29555==     in use at exit: 0 bytes in 0 blocks
==29555==   total heap usage: 9 allocs, 9 frees, 72,848 bytes allocated
==29555== 
==29555== All heap blocks were freed -- no leaks are possible
==29555== 
==29555== For counts of detected and suppressed errors, rerun with: -v
==29555== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
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