Allocating memory to nested Structures within a Structure

[Amit_Basnak]

Dear Friends

I have the follwoing function "tss_fe_get_own_info" which has the
arguments as shows below
tss_fe_get_own_info(char *user_id, tss_user_profile_t
**p_buf_UserSecInfo, error_status_t *retStatus)

// Structure tss_user_profile_t from the function

typedef struct {
tss_user_info_t user_info;
odss_attribute_value_list_t *ProcAttr;
odss_attribute_value_list_t *BkOffAttr;
odss_attribute_value_list_t *WkClusterAttr;
odss_attribute_value_list_t *CSUAttr;
} tss_user_profile_t;

// Structure tss_user_info_t
typedef struct
{
char user_uuid[USER_UUID_LEN+1];
char user_sec_info_status[USER_ACC_STATUS_LEN+1];
char user_id[USER_ID_LEN+1];
char user_name[USER_NAME_LEN+1];
char employee_id[EMPLOYEE_ID_LEN+1];
char job_title[JOB_TITLE_LEN+1];
char job_type[JOB_TYPE_LEN+1];
char loc_addr[LOC_ADDR_LEN+1];
char loc_country_code[LOC_CTRY_CODE_LEN+1];
char loc_city_code[LOC_CITY_CODE_LEN+1];
char telephone_number[TELE_NUM_LEN+1];
char expense_code[EXPENSE_CODE_LEN+1];
char proc_locn_csu[PROC_LOCN_CSU_LEN+1];
char proc_locn_rpf[RPF_CODE_LEN+1];
char prim_wk_cluster[PRM_WK_CLUS_LEN+1];
char experience[EXPERIENCE_LEN+1];
char oracle_id[ORACLE_ID_LEN+1];
char oracle_pwd[ORACLE_PWD_LEN+1];
char user_group[USER_GROUP_LEN+1];
char date_modified[DATE_STR_LEN+1];
char date_valid[DATE_STR_LEN+1];
} tss_user_info_t;

// odss_attribute_value_list_t
typedef struct odss_attribute_value_list_t
{
[ptr] odss_attribute_value_t *attribute_value;
[ptr] struct odss_attribute_value_list_t *next;
} odss_attribute_value_list_t;

// Structure odss_attribute_value_t

typedef struct
{
unsigned32 length;
[string, ptr] char *attribute;
} odss_attribute_value_t;

If I want to allocate the memory to nested structures in that case
I have done the follwoing


tss_user_profile_t **p_buf_UserSecInfo;
*p_buf_UserSecInfo = new tss_user_profile_t;
memset((void*) *p_buf_UserSecInfo, '\0',
sizeof(tss_user_profile_t)); // at this point the profile is
allocated, as well as the user_info

unsigned32 len1 = 0;
char *attr1 = NULL;

odss_attribute_value_list_t *tmp1 = (*p_buf_UserSecInfo)->ProcAttr; //
Allocates the ProcAttr pointer :

ProcAttr = new odss_attribute_value_list_t;
ProcAttr->attribute_value = new odss_attribute_value_t;
ProcAttr->attribute_value->length = len1;
ProcAttr->attribute_value->attribute = attr1;
ProcAttr->next = tmp1;

unsigned32 len2 = 0;
char *attr2 = NULL;

odss_attribute_value_list_t *tmp2 = (*p_buf_UserSecInfo)-

BkOffAttr; // Allocates the BkOffAttr pointer :

BkOffAttr = new odss_attribute_value_list_t;
BkOffAttr->attribute_value = new odss_attribute_value_t;
BkOffAttr->attribute_value->length = len2;
BkOffAttr->attribute_value->attribute = attr2;
BkOffAttr->next = tmp2;

unsigned32 len3 = 0;
char *attr3 = NULL;

odss_attribute_value_list_t *tmp3 = (*p_buf_UserSecInfo)-

WkClusterAttr; // Allocates the WkClusterAttr pointer :

WkClusterAttr = new odss_attribute_value_list_t;
WkClusterAttr->attribute_value = new odss_attribute_value_t;
WkClusterAttr->attribute_value->length = len3;
WkClusterAttr->attribute_value->attribute = attr3;
WkClusterAttr->next = tmp3;

unsigned32 len4 = 0;
char *attr4 = NULL;

odss_attribute_value_list_t *tmp4 = (*p_buf_UserSecInfo)->CSUAttr; //
Allocates the CSUAttr pointer :

CSUAttr = new odss_attribute_value_list_t;
CSUAttr->attribute_value = new odss_attribute_value_t;
CSUAttr->attribute_value->length = len4;
CSUAttr->attribute_value->attribute = attr4;
CSUAttr->next = tmp4;

Please let me know if this is the correct way to allocate the memory


thanks
Amit

 

[jean.daniel.michaud]

Hi,

Dear Friends

I have the follwoing function "tss_fe_get_own_info" which has the
arguments as shows below
tss_fe_get_own_info(char *user_id, tss_user_profile_t
**p_buf_UserSecInfo, error_status_t *retStatus)

// Structure tss_user_profile_t from the function


tss_user_profile_t **p_buf_UserSecInfo;
*p_buf_UserSecInfo = new tss_user_profile_t;
memset((void*) *p_buf_UserSecInfo, '\0',

Here you got a pointer to a pointer. If the first thing you do after
declaration is dereferencing the pointer like this:
*p_buf_UserSecInfo, I think you are running into trouble, because
p_buf_UserSecInfo is not initialized and is pointing nowhere (or
anywhere) in memory. Dereferencing it like you do has no sense... Who
says pointer says array. If you got a pointer of pointer like this
it's because you want a array of pointers. You'd better do something
like:

tss_user_profile_t **p_buf_UserSecInfo;
p_buf_UserSecInfo = new *tss_user_profile_t[SOME_INTERGER_VALUE]; //
With SOME_INTERGER_VALUE possibly equal to 1
for (unsigned int i = 0; i < SOME_INTERGER_VALUE; ++i)
{
p_buf_UserSecInfo = new tss_user_profile_t;
memset((void*) p_buf_UserSecInfo, 0, sizeof(tss_user_profile_t));
}

unsigned32 len1 = 0;
char *attr1 = NULL;

odss_attribute_value_list_t *tmp1 = (*p_buf_UserSecInfo)->ProcAttr;

Again, I don't get what you do. (*p_buf_UserSecInfo)->ProcAttr is NULL
here (remember the memset), so tmp1 is NULL too.

ProcAttr = new odss_attribute_value_list_t;

ProcAttr is not declared anywhere, so it should not compile.

ProcAttr->attribute_value = new odss_attribute_value_t;
ProcAttr->attribute_value->length = len1;
ProcAttr->attribute_value->attribute = attr1;

attr1 is NULL anyway so you'better write
ProcAttr->attribute_value->attribute = NULL;

ProcAttr->next = tmp1;

Here too:
ProcAttr->next = NULL;

I guess, what do you want to do is:

(*p_buf_UserSecInfo)->ProcAttr = new odss_attribute_value_list_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value = new
odss_attribute_value_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->length = 0;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->attribute = NULL;
(*p_buf_UserSecInfo)->ProcAttr->next = NULL;

Please let me know if this is the correct way to allocate the memory

Or maybe I just didn't understand your post at all

JD

 

[Amit_Basnak]

Hi,

Dear Friends

I have the follwoing function "tss_fe_get_own_info" which has the
arguments as shows below
tss_fe_get_own_info(char *user_id, tss_user_profile_t
**p_buf_UserSecInfo, error_status_t *retStatus)

// Structure tss_user_profile_t from the function

tss_user_profile_t **p_buf_UserSecInfo;
*p_buf_UserSecInfo = new tss_user_profile_t;
memset((void*) *p_buf_UserSecInfo, '\0',

Here you got a pointer to a pointer. If the first thing you do after
declaration is dereferencing the pointer like this:
*p_buf_UserSecInfo, I think you are running into trouble, because
p_buf_UserSecInfo is not initialized and is pointing nowhere (or
anywhere) in memory. Dereferencing it like you do has no sense... Who
says pointer says array. If you got a pointer of pointer like this
it's because you want a array of pointers. You'd better do something
like:

tss_user_profile_t **p_buf_UserSecInfo;
p_buf_UserSecInfo = new *tss_user_profile_t[SOME_INTERGER_VALUE]; //
With SOME_INTERGER_VALUE possibly equal to 1
for (unsigned int i = 0; i < SOME_INTERGER_VALUE; ++i)
{
p_buf_UserSecInfo = new tss_user_profile_t;
memset((void*) p_buf_UserSecInfo, 0, sizeof(tss_user_profile_t));

}

unsigned32 len1 = 0;
char *attr1 = NULL;

odss_attribute_value_list_t *tmp1 = (*p_buf_UserSecInfo)->ProcAttr;

Again, I don't get what you do. (*p_buf_UserSecInfo)->ProcAttr is NULL
here (remember the memset), so tmp1 is NULL too.

ProcAttr = new odss_attribute_value_list_t;

ProcAttr is not declared anywhere, so it should not compile.

ProcAttr->attribute_value = new odss_attribute_value_t;
ProcAttr->attribute_value->length = len1;
ProcAttr->attribute_value->attribute = attr1;

attr1 is NULL anyway so you'better write
ProcAttr->attribute_value->attribute = NULL;

ProcAttr->next = tmp1;

Here too:
ProcAttr->next = NULL;

I guess, what do you want to do is:

(*p_buf_UserSecInfo)->ProcAttr = new odss_attribute_value_list_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value = new
odss_attribute_value_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->length = 0;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->attribute = NULL;
(*p_buf_UserSecInfo)->ProcAttr->next = NULL;

Please let me know if this is the correct way to allocate the memory

Or maybe I just didn't understand your post at all

JD

Hi JD thanks for your comments.
here is the background of what Im doiong This is SOAP Interface that
Im writing and method tss_fe_get_own_info calls to DCE ( Distributed
Computing Environment ) and DCE internally calls Oracle DB using
pro*c. Now in the function
char *user_id = IN parameter which is passed to SOAP from Front End
( J2EE)
and tss_user_profile_t **p_buf_UserSecInfo , error_status_t
*retStatus are OUT parameters sent from DCE to Frront End via SOAP.
I have to stored the return object from DCE to the structure
tss_user_profile_t
Since its a linked list type , I have to allocate memory to
tss_user_profile_t structure dynamically using new operator so that I
can store the return object. Structure tss_user_profile_t has nested
structures with pointers , things got complicated.
This is what I have now and its compiling
tss_user_profile_t **p_buf_UserSecInfo;
*p_buf_UserSecInfo = new tss_user_profile_t[1];
for (unsigned int i = 0; i < 1; ++i)
{
p_buf_UserSecInfo = new tss_user_profile_t;
memset((void*)p_buf_UserSecInfo,0,
sizeof(tss_user_profile_t));

}

(*p_buf_UserSecInfo)->ProcAttr = new odss_attribute_value_list_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value = new
odss_attribute_value_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->length = 0;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->attribute = NULL;
(*p_buf_UserSecInfo)->ProcAttr->next = NULL;

Now If I want to free the allocated memory then do I need to write
delete for all allocated structures ?
How it could be done
Please let me know
Thanks for your comments
Amit

 

[jean.daniel.michaud]

Hi,

[snip]

This is what I have now and its compiling
tss_user_profile_t **p_buf_UserSecInfo;
*p_buf_UserSecInfo = new tss_user_profile_t[1];
for (unsigned int i = 0; i < 1; ++i)
{
p_buf_UserSecInfo = new tss_user_profile_t;
memset((void*)p_buf_UserSecInfo,0,
sizeof(tss_user_profile_t));

}

If you are just allocating one element, you don't need a for loop...

tss_user_profile_t **p_buf_UserSecInfo;
*p_buf_UserSecInfo = new tss_user_profile_t[1];
p_buf_UserSecInfo[0] = new tss_user_profile_t;
memset((void*)p_buf_UserSecInfo[0], 0, sizeof(tss_user_profile_t));

(*p_buf_UserSecInfo)->ProcAttr = new odss_attribute_value_list_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value = new
odss_attribute_value_t;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->length = 0;
(*p_buf_UserSecInfo)->ProcAttr->attribute_value->attribute = NULL;
(*p_buf_UserSecInfo)->ProcAttr->next = NULL;

Now If I want to free the allocated memory then do I need to write
delete for all allocated structures ?
How it could be done

Well, yes, for every new, you shall have a delete, otherwise you
would end up with memory leaks. And to delete a linked list a while
loop seems appropriate...

odss_attribute_value_list_t *list = (*p_buf_UserSecInfo)->ProcAttr;
while (list)
{
odss_attribute_value_list_t *tmp = list->next;
delete list->attribute_value;
delete list;
list = tmp;
}

Here you go.
I would advise you to have a look to some C tutorial before playing
around with pointers and dynamic memory allocation:
http://einstein.drexel.edu/courses/CompPhys/General/C_basics/c_tutorial.html#pointers

JD