Re: [RFC PATCH 1/2] Add libv4l2rds library (with changes proposed in RFC)
On Thu, Aug 9, 2012 at 11:58 AM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> Other then that I've some minor remarks (comments inline), with all those
> fixed, this one is could to go. So hopefully the next version can be added
> to git master!
I'm very happy to hear that :)
>
>
> On 08/07/2012 05:11 PM, Konke Radlow wrote:
>>
>> ---
>> Makefile.am | 3 +-
>> configure.ac | 7 +-
>> lib/include/libv4l2rds.h | 228 ++++++++++
>> lib/libv4l2rds/Makefile.am | 11 +
>> lib/libv4l2rds/libv4l2rds.c | 953
>> +++++++++++++++++++++++++++++++++++++++
>> lib/libv4l2rds/libv4l2rds.pc.in | 11 +
>> 6 files changed, 1211 insertions(+), 2 deletions(-)
>> create mode 100644 lib/include/libv4l2rds.h
>> create mode 100644 lib/libv4l2rds/Makefile.am
>> create mode 100644 lib/libv4l2rds/libv4l2rds.c
>> create mode 100644 lib/libv4l2rds/libv4l2rds.pc.in
>>
>
> <snip>
>
>
>> diff --git a/lib/include/libv4l2rds.h b/lib/include/libv4l2rds.h
>> new file mode 100644
>> index 0000000..4aa8593
>> --- /dev/null
>> +++ b/lib/include/libv4l2rds.h
>> @@ -0,0 +1,228 @@
>> +/*
>> + * Copyright 2012 Cisco Systems, Inc. and/or its affiliates. All rights
>> reserved.
>> + * Author: Konke Radlow <koradlow@xxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU Lesser General Public License as
>> published by
>> + * the Free Software Foundation; either version 2.1 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA
>> 02110-1335 USA
>> + */
>> +
>> +#ifndef __LIBV4L2RDS
>> +#define __LIBV4L2RDS
>> +
>> +#include <errno.h>
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <stdbool.h>
>> +#include <unistd.h>
>> +#include <stdint.h>
>> +#include <time.h>
>> +#include <sys/types.h>
>> +#include <sys/mman.h>
>> +#include <config.h>
>
>
> You should never include config.h in a public header, also
> are all the headers really needed for the prototypes in this header?
>
> I don't think so! Please move all the unneeded ones to the libv4l2rds.c
> file!
>
That's true, I don't know why I had all these include directives in the public
header. After cleaning up we're left with only three (stdbool, stdint
and videodev2)
>
>> +
>> +#include <linux/videodev2.h>
>> +
>> +#ifdef __cplusplus
>> +extern "C" {
>> +#endif /* __cplusplus */
>> +
>> +#if HAVE_VISIBILITY
>> +#define LIBV4L_PUBLIC __attribute__ ((visibility("default")))
>> +#else
>> +#define LIBV4L_PUBLIC
>> +#endif
>> +
>> +/* used to define the current version (version field) of the v4l2_rds
>> struct */
>> +#define V4L2_RDS_VERSION (1)
>> +
>
>
> What is the purpose of this field? Once we've released a v4l-utils with this
> library we are stuck to the API we've defined, having a version field &
> changing it,
> won't stop us from breaking existing apps, so once we've an official release
> we
> simply cannot make ABI breaking changes, which is why most of my review
> sofar
> has concentrated on the API side :)
>
> I suggest dropping this define and the version field from the struct.
>
As Hans mentioned this version field is not supposed to denote the API version,
but rather the version of the v4l2_rds_handle struct. This struct could then
theoretically be updated in the future and provide applications a way
of verifying
their compatibility with the rds-library version installed on the system.
>
>> +/* Constants used to define the size of arrays used to store RDS
>> information */
>> +#define MAX_ODA_CNT 18 /* there are 16 groups each with type a or
>> b. Of these
>> + * 32 distinct groups, 18 can be used for ODA
>> purposes */
>> +#define MAX_AF_CNT 25 /* AF Method A allows a maximum of 25 AFs to be
>> defined
>> + * AF Method B does not impose a limit on the
>> number of AFs
>> + * but it is not fully supported at the moment and
>> will
>> + * not receive more than 25 AFs */
>> +
>> +/* Define Constants for the possible types of RDS information
>> + * used to address the relevant bit in the valid_fields bitmask */
>> +#define V4L2_RDS_PI 0x01 /* Program Identification */
>> +#define V4L2_RDS_PTY 0x02 /* Program Type */
>> +#define V4L2_RDS_TP 0x04 /* Traffic Program */
>> +#define V4L2_RDS_PS 0x08 /* Program Service Name */
>> +#define V4L2_RDS_TA 0x10 /* Traffic Announcement */
>> +#define V4L2_RDS_DI 0x20 /* Decoder Information */
>> +#define V4L2_RDS_MS 0x40 /* Music / Speech flag */
>> +#define V4L2_RDS_PTYN 0x80 /* Program Type Name */
>> +#define V4L2_RDS_RT 0x100 /* Radio-Text */
>> +#define V4L2_RDS_TIME 0x200 /* Date and Time information */
>> +#define V4L2_RDS_TMC 0x400 /* TMC availability */
>> +#define V4L2_RDS_AF 0x800 /* AF (alternative freq) available
>> */
>> +#define V4L2_RDS_ECC 0x1000 /* Extended County Code */
>> +#define V4L2_RDS_LC 0x2000 /* Language Code */
>> +
>> +/* Define Constants for the state of the RDS decoding process
>> + * used to address the relevant bit in the decode_information bitmask */
>> +#define V4L2_RDS_GROUP_NEW 0x01 /* New group received */
>> +#define V4L2_RDS_ODA 0x02 /* Open Data Group announced */
>> +
>> +/* Decoder Information (DI) codes
>> + * used to decode the DI information according to the RDS standard */
>> +#define V4L2_RDS_FLAG_STEREO 0x01
>> +#define V4L2_RDS_FLAG_ARTIFICIAL_HEAD 0x02
>> +#define V4L2_RDS_FLAG_COMPRESSED 0x04
>> +#define V4L2_RDS_FLAG_STATIC_PTY 0x08
>> +
>> +/* struct to encapsulate one complete RDS group */
>> +/* This structure is used internally to store data until a complete RDS
>> + * group was received and group id dependent decoding can be done.
>> + * It is also used to provide external access to uninterpreted RDS groups
>> + * when manual decoding is required (e.g. special ODA types) */
>> +struct v4l2_rds_group {
>> + uint16_t pi; /* Program Identification */
>> + char group_version; /* group version ('A' / 'B') */
>> + uint8_t group_id; /* group number (0..16) */
>> +
>> + /* uninterpreted data blocks for decoding (e.g. ODA) */
>> + uint8_t data_b_lsb;
>> + uint8_t data_c_msb;
>> + uint8_t data_c_lsb;
>> + uint8_t data_d_msb;
>> + uint8_t data_d_lsb;
>> +};
>> +
>> +/* struct to encapsulate some statistical information about the decoding
>> process */
>> +struct v4l2_rds_statistics {
>> + uint32_t block_cnt; /* total amount of received blocks
>> */
>> + uint32_t group_cnt; /* total amount of successfully
>> + * decoded groups */
>> + uint32_t block_error_cnt; /* blocks that were marked as
>> erroneous
>> + * and had to be dropped */
>> + uint32_t group_error_cnt; /* group decoding processes that
>> had to be
>> + * aborted because of erroneous
>> blocks
>> + * or wrong order of blocks */
>> + uint32_t block_corrected_cnt; /* blocks that contained 1-bit
>> errors
>> + * which were corrected */
>> + uint32_t group_type_cnt[16]; /* number of occurrence for each
>> + * defined RDS group */
>> +};
>> +
>> +/* struct to encapsulate the definition of one ODA (Open Data
>> Application) type */
>> +struct v4l2_rds_oda {
>> + uint8_t group_id; /* RDS group used to broadcast this ODA */
>> + char group_version; /* group version (A / B) for this ODA */
>> + uint16_t aid; /* Application Identification for this
>> ODA,
>> + * AIDs are centrally administered by the
>> + * RDS Registration Office (rds.org.uk) */
>> +};
>> +
>> +/* struct to encapsulate an array of all defined ODA types for a channel
>> */
>> +/* This structure will grow with ODA announcements broadcasted in type 3A
>> + * groups, that were verified not to be no duplicates or redefinitions */
>> +struct v4l2_rds_oda_set {
>> + uint8_t size; /* number of ODAs defined by this channel
>> */
>> + struct v4l2_rds_oda oda[MAX_ODA_CNT];
>> +};
>> +
>> +/* struct to encapsulate an array of Alternative Frequencies for a
>> channel */
>> +/* Every channel can send out AFs for his program. The number of AFs that
>> + * will be broadcasted is announced by the channel */
>> +struct v4l2_rds_af_set {
>> + uint8_t size; /* size of the set (might be
>> smaller
>> + * than the announced size) */
>> + uint8_t announced_af; /* number of announced AF */
>> + uint32_t af[MAX_AF_CNT]; /* AFs defined in Hz */
>> +};
>> +
>> +/* struct to encapsulate state and RDS information for current decoding
>> process */
>> +/* This is the structure that will be used by external applications, to
>> + * communicate with the library and get access to RDS data */
>> +struct v4l2_rds {
>> + uint32_t version; /* version number of this structure */
>> +
>> + /** state information **/
>> + uint32_t decode_information; /* state of decoding process */
>> + uint32_t valid_fields; /* currently valid info fields
>> + * of this structure */
>> +
>> + /** RDS info fields **/
>> + bool is_rbds; /* use RBDS standard version of LUTs */
>> + uint16_t pi; /* Program Identification */
>> + uint8_t ps[9]; /* Program Service Name, UTF-8 encoding,
>> + * '\0' terminated */
>> + uint8_t pty; /* Program Type */
>> + uint8_t ptyn[9]; /* Program Type Name, UTF-8 encoding,
>> + * '\0' terminated */
>> + bool ptyn_ab_flag; /* PTYN A/B flag (toggled), to signal
>> + * change of PTYN */
>> + uint8_t rt_length; /* length of RT string */
>> + uint8_t rt[65]; /* Radio-Text string, UTF-8 encoding,
>> + * '\0' terminated */
>> + bool rt_ab_flag; /* RT A/B flag (toggled), to signal
>> + * transmission of new RT */
>> + bool ta; /* Traffic Announcement */
>> + bool tp; /* Traffic Program */
>> + bool ms; /* Music / Speech flag */
>> + uint8_t di; /* Decoder Information */
>> + uint8_t ecc; /* Extended Country Code */
>> + uint8_t lc; /* Language Code */
>> + time_t time; /* Time and Date of transmission */
>> +
>> + struct v4l2_rds_statistics rds_statistics;
>> + struct v4l2_rds_oda_set rds_oda; /* Open Data Services */
>> + struct v4l2_rds_af_set rds_af; /* Alternative Frequencies
>> */
>> +};
>> +
>> +/* v4l2_rds_init() - initializes a new decoding process
>> + * @is_rbds: defines which standard is used: true=RBDS, false=RDS
>> + *
>> + * initialize a new instance of the RDS-decoding struct and return
>> + * a handle containing state and RDS information, used to interact
>> + * with the library functions */
>> +LIBV4L_PUBLIC struct v4l2_rds *v4l2_rds_create(bool is_rdbs);
>> +
>> +/* frees all memory allocated for the RDS-decoding struct */
>> +LIBV4L_PUBLIC void v4l2_rds_destroy(struct v4l2_rds *handle);
>> +
>> +/* resets the RDS information in the handle to initial values
>> + * e.g. can be used when radio channel is changed
>> + * @reset_statistics: true = set all statistic values to 0, false = keep
>> them untouched */
>> +LIBV4L_PUBLIC void v4l2_rds_reset(struct v4l2_rds *handle, bool
>> reset_statistics);
>> +
>> +/* adds a raw RDS block to decode it into RDS groups
>> + * @return: bitmask with with updated fields set to 1
>> + * @rds_data: 3 bytes of raw RDS data, obtained by calling read()
>> + * on RDS capable V4L2 devices */
>> +LIBV4L_PUBLIC uint32_t v4l2_rds_add(struct v4l2_rds *handle, struct
>> v4l2_rds_data *rds_data);
>> +
>> +/*
>> + * group of functions to translate numerical RDS data into strings
>> + *
>> + * return program description string defined in the RDS/RBDS Standard
>> + * ! return value deepens on selected Standard !*/
>
>
> ^^^^^^^ Typo!
>
>
>> +LIBV4L_PUBLIC const char *v4l2_rds_get_pty_str(const struct v4l2_rds
>> *handle);
>> +LIBV4L_PUBLIC const char *v4l2_rds_get_language_str(const struct v4l2_rds
>> *handle);
>> +LIBV4L_PUBLIC const char *v4l2_rds_get_country_str(const struct v4l2_rds
>> *handle);
>> +LIBV4L_PUBLIC const char *v4l2_rds_get_coverage_str(const struct v4l2_rds
>> *handle);
>> +
>> +/* returns a pointer to the last decoded RDS group, in order to give raw
>> + * access to RDS data if it is required (e.g. ODA decoding) */
>> +LIBV4L_PUBLIC const struct v4l2_rds_group *v4l2_rds_get_group
>> + (const struct v4l2_rds *handle);
>> +
>> +
>> +#ifdef __cplusplus
>> +}
>> +#endif /* __cplusplus */
>> +#endif
>
>
> <snip>
>
> The rest looks good to me.
>
> Regards,
>
> Hans
>
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