Philip Prindeville wrote:
> Manu Abraham wrote:
>
>> Henrik Sjoberg wrote:
>>
>>> Hi,
>>>
>>> This is a bit embarrassing, but my latest patch contained pmt test
>>> code,
>>> which caused it not to work. I have prepared another one (third one's a
>>> charm?) which I have actually tested against cvs dvb-apps. It works
>>> ok for
>>> me.
>>>
>>>
>>>
>>
>> Any comments on this patch ? If none i can check it in.
>>
>>
>> Manu
>
>
>
> Yeah, minor comments... Should use space after keywords like "if"
> and "for".
>
Yeah, these should be fixed .. Henrik .. ?
> General comment about the code is that there are a lot of "magic numbers"
> that aren't evident to the casual reader:
>
> + if(p_descriptor->descriptor_tag != 0x09) {
> + printf("ERROR::Trying to copy a CA descriptor with
> incorrect tag [%d]. Bailing out.\n",
> + p_descriptor->descriptor_tag);
> + return 16;
> + }
>
> It's not clear what 0x09 signifies here... This should be either a
> "const unsigned"
> or else a #define... Ditto for the 16...
>
These descriptors are defined in ISO13818 and other relevant documents..
Maybe we need to #define the descriptors...., but the descriptors are
quite a lot to be defined thus.,
> There are no other printf()'s in this library... And errors should
> usually
> go to STDERR anyway... But in general, a library should return error
> status but not print messages. Let the application decide if it wants to
> generate a message or not.
>
Hmm... i think that was for debugging, Anyway you are right. But the
problem here is if we don't see the error's/messages it would be quite
difficult to debug the lib ..
> More comments...
>
> +static void try_move_ca_descriptors(struct service_info *p_si)
> +{
> + int i;
> + int j;
> + int k;
> + int l;
> + struct streams *p_stream1;
> + struct streams *p_stream2;
> + struct descriptor *p_desc1;
> + struct descriptor *p_desc2;
> + int movable = 1;
> + int ca_descriptors = 0;
> + int num_ca1;
> + int num_ca2;
> + int found_match;
> + int found;
>
> Use commas and group variables of identical types.
>
Yeah ..
> Do we need:
>
> + //int j, k, l, i2, j2;
>
> In:
>
> printf("%s: Setting PMT Command\n", __FUNCTION__);
> - for (i = 0; i < p_en50221_pmt_object->program_desc_count; i++) {
> - if
> (p_en50221_pmt_object->p_en50221_prog_desc[i].descriptor_tag
> == 0x09) {
> - printf("%s: CA descriptor found @ PROGRAM
> Level, Setting CA PMT command=[%02x]\n", __FUNCTION__, pmt_command);
> + if (p_en50221_pmt_object->program_desc_count > 0) {
> + printf("%s: CA descriptor(s) found @ PROGRAM Level,
> Setting CA PMT command=[%02x]\n",
> + __FUNCTION__, pmt_command);
> p_en50221_pmt_object->ca_pmt_cmd_id = pmt_command;
> object_length += 8;
> }
> - }
>
>
> If you're changing the level of nesting, then the indent should change
> as well...
>
True...
> In:
>
> + sprintf(message, "%s: %s={", __FUNCTION__, type);
> +
> + sprintf(temp, "Length=%d", ptr[pos++]);
> + strcat(message, temp);
> + list_management = ptr[pos++];
> + sprintf(temp, ":CA_PMT_ListManagement=%d", list_management);
> + strcat(message, temp);
> + sprintf(temp, ":ProgramNumber=0x%02x%02x=%d", ptr[pos + 0],
> + ptr[pos + 1], (ptr[pos + 0] << 8) + ptr[pos + 1]);
> + strcat(message, temp);
> + pos += 2;
> + sprintf(temp, ":VersionNumber=%d", (ptr[pos++] >> 1) & 0x1f);
> + strcat(message, temp);
> + program_info_length = ((ptr[pos + 0] << 8) & 0x0f) + ptr[pos +
> 1];
> + pos += 2;
> + sprintf(temp, ":Program={");
> + strcat(message, temp);
>
>
> I would set up a FILE * to point to the buffer, and therefore guard
> against overflowing the size of the buffer.
???.
> Looking a little further,
> though, we see:
>
> + sprintf(temp, "}\n");
> + strcat(message, temp);
> +
> + printf(message);
> +
> + return 0;
>
> So I'm stumped... Why all of this trouble to build a buffer and then
> printf(), when it could be printf'd as you go?
>
That message is then later on copied out, to create another message.
The printf's are temporarily for debugging at the moment.
> Also, printf(message) is dangerous... What if "message" contains
> "%s"? Should be using fputs(message, STDOUT) instead... And
> that would avoid using:
>
> + char message[2048];
>
> which is a lot of stack space.
You mean allocate in the heap.. ?
>
> Not sure why:
>
> uint16_t debug_parse_message(struct ca_msg *p_ca_msg, uint16_t length)
>
> needs a return value, if it's an invariant "0".
>
> Regarding changes like:
>
> +++ lib/libdvbsi/channels.c 18 Oct 2005 16:44:42 -0000
> @@ -102,7 +102,6 @@
> static int parse_param(char *val, const param *p_list, int list_size)
> {
> int i;
> -
> for (i = 0; i < list_size; i++) {
> if (strcasecmp(p_list[i].name, val) == 0)
> return p_list[i].value;
>
> Please avoid whitespace only changes. They make merging multiple
> branches hellish.
>
> Also, many people like a blank line between declarations and statements.
>
> Looking at:
>
> + if (p_descriptor->extended_event.length_of_items)
> + free(p_descriptor->extended_event.p_items);
> + if (p_descriptor->extended_event.text_length)
> + free(p_descriptor->extended_event.p_text_char);
>
>
> Don't bother. free(NULL) is perfectly fine. I would, on the
> other hand, always NULL out a pointer that I've freed, unless
> it is about to go out of scope. I.e.:
>
> free(p_description->extended_event.p_text_char);
> p_description->extended_event.p_text_char = NULL;
>
> and thus avoid memory leaks or double-frees. Same elsewhere.
>
> In:
>
> + p_descriptor->short_event.iso_639_language_code =
> + (((buf[pos] << 8) | buf[pos + 1]) << 8) | buf[pos + 2];
>
>
> Not sure I get this... Shouldn't "pos" be shifted more bits? Otherwise,
> "pos" and "pos + 1" will be combined... Oh, got it. Didn't match
> parens.
> Well, I'd still write:
>
> (buf[pos] << 16) | (buf[pos + 1] << 8) | buf[pos + 2];
>
> instead...
>
> Regarding:
>
> + struct descriptor *p_en50221_streams_desc =
> + (struct descriptor *) malloc(sizeof (struct
> descriptor) * p_streams->streams_desc_count);
>
> malloc() returns a "void *", which is an untyped pointer. It doesn't
> need
> to be cast. Also:
>
Right.
> p = malloc(sizeof(*p));
>
> is a lot more clear than:
>
> p = malloc(sizeof(struct descriptor))
>
> since you don't have to flip back and confirm that "p" is of type
> "struct descriptor". Same applies whether you are allocating a
> single element or an array of them.
This is not quite right. On LKML, this has been proven not advisable.
You can see a lengthy discussion of this on LKML with a thread like this
http://marc.theaimsgroup.com/?t=112703827100001&r=1&w=2
You can see a lot of comments on the same.
Manu
