drivers/media/test-drivers/vidtv/vidtv_psi.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * This file contains the logic to work with MPEG Program-Specific Information.
  * These are defined both in ISO/IEC 13818-1 (systems) and ETSI EN 300 468.
  * PSI is carried in the form of table structures, and although each table might
  * technically be broken into one or more sections, we do not do this here,
  * hence 'table' and 'section' are interchangeable for vidtv.
  *
  * This code currently supports three tables: PAT, PMT and SDT. These are the
  * bare minimum to get userspace to recognize our MPEG transport stream. It can
  * be extended to support more PSI tables in the future.
  *
  * Copyright (C) 2020 Daniel W. S. Almeida
  */

 #ifndef VIDTV_PSI_H
 #define VIDTV_PSI_H

 #include <linux/types.h>
 #include <asm/byteorder.h>

 /*
  * all section lengths start immediately after the 'section_length' field
  * see ISO/IEC 13818-1 : 2000 and ETSI EN 300 468 V 1.10.1 for
  * reference
  */
 #define PAT_LEN_UNTIL_LAST_SECTION_NUMBER 5
 #define PMT_LEN_UNTIL_PROGRAM_INFO_LENGTH 9
 #define SDT_LEN_UNTIL_RESERVED_FOR_FUTURE_USE 8
 #define MAX_SECTION_LEN 1021
 #define VIDTV_PAT_PID 0 /* mandated by the specs */
 #define VIDTV_SDT_PID 0x0011 /* mandated by the specs */

 enum vidtv_psi_descriptors {
 	REGISTRATION_DESCRIPTOR	= 0x05, /* See ISO/IEC 13818-1 section 2.6.8 */
 	SERVICE_DESCRIPTOR = 0x48, /* See ETSI EN 300 468 section 6.2.33 */
 };

 enum vidtv_psi_stream_types {
 	STREAM_PRIVATE_DATA = 0x06, /* see ISO/IEC 13818-1 2000 p. 48 */
 };

 /**
  * struct vidtv_psi_desc - A generic PSI descriptor type.
  * The descriptor length is an 8-bit field specifying the total number of bytes of the data portion
  * of the descriptor following the byte defining the value of this field.
  */
 struct vidtv_psi_desc {
 	struct vidtv_psi_desc *next;
 	u8 type;
 	u8 length;
 	u8 data[];
 } __packed;

 /**
  * struct vidtv_psi_desc_service - Service descriptor.
  * See ETSI EN 300 468 section 6.2.33.
  */
 struct vidtv_psi_desc_service {
 	struct vidtv_psi_desc *next;
 	u8 type;
 	u8 length;

 	u8 service_type;
 	u8 provider_name_len;
 	char *provider_name;
 	u8 service_name_len;
 	char *service_name;
 } __packed;

 /**
  * struct vidtv_psi_desc_registration - A registration descriptor.
  * See ISO/IEC 13818-1 section 2.6.8
  */
 struct vidtv_psi_desc_registration {
 	struct vidtv_psi_desc *next;
 	u8 type;
 	u8 length;

 	/*
 	 * The format_identifier is a 32-bit value obtained from a Registration
 	 * Authority as designated by ISO/IEC JTC 1/SC 29.
 	 */
 	__be32 format_id;
 	/*
 	 * The meaning of additional_identification_info bytes, if any, are
 	 * defined by the assignee of that format_identifier, and once defined
 	 * they shall not change.
 	 */
 	u8 additional_identification_info[];
 } __packed;

 /**
  * struct vidtv_psi_table_header - A header that is present for all PSI tables.
  */
 struct vidtv_psi_table_header {
 	u8  table_id;

 	__be16 bitfield; /* syntax: 1, zero: 1, one: 2, section_length: 13 */

 	__be16 id; /* TS ID */
 	u8  current_next:1;
 	u8  version:5;
 	u8  one2:2;
 	u8  section_id;	/* section_number */
 	u8  last_section; /* last_section_number */
 } __packed;

 /**
  * struct vidtv_psi_table_pat_program - A single program in the PAT
  * See ISO/IEC 13818-1 : 2000 p.43
  */
 struct vidtv_psi_table_pat_program {
 	__be16 service_id;
 	__be16 bitfield; /* reserved: 3, program_map_pid/network_pid: 13 */
 	struct vidtv_psi_table_pat_program *next;
 } __packed;

 /**
  * struct vidtv_psi_table_pat - The Program Allocation Table (PAT)
  * See ISO/IEC 13818-1 : 2000 p.43
  */
 struct vidtv_psi_table_pat {
 	struct vidtv_psi_table_header header;
 	u16 programs; /* Included by libdvbv5, not part of the table and not actually serialized */
 	struct vidtv_psi_table_pat_program *program;
 } __packed;

 /**
  * struct vidtv_psi_table_sdt_service - Represents a service in the SDT.
  * see ETSI EN 300 468 v1.15.1 section 5.2.3.
  */
 struct vidtv_psi_table_sdt_service {
 	__be16 service_id;
 	u8 EIT_present_following:1;
 	u8 EIT_schedule:1;
 	u8 reserved:6;
 	__be16 bitfield; /* running_status: 3, free_ca:1, desc_loop_len:12 */
 	struct vidtv_psi_desc *descriptor;
 	struct vidtv_psi_table_sdt_service *next;
 } __packed;

 /**
  * struct vidtv_psi_table_sdt - Represents the Service Description Table
  * see ETSI EN 300 468 v1.15.1 section 5.2.3.
  */

 struct vidtv_psi_table_sdt {
 	struct vidtv_psi_table_header header;
 	__be16 network_id; /* original_network_id */
 	u8  reserved;
 	struct vidtv_psi_table_sdt_service *service;
 } __packed;

 /**
  * enum service_running_status - Status of a SDT service.
  * see ETSI EN 300 468 v1.15.1 section 5.2.3 table 6.
  */
 enum service_running_status {
 	RUNNING = 0x4,
 };

 /**
  * enum service_type - The type of a SDT service.
  * see ETSI EN 300 468 v1.15.1 section 6.2.33, table 81.
  */
 enum service_type {
 	/* see ETSI EN 300 468 v1.15.1 p. 77 */
 	DIGITAL_TELEVISION_SERVICE = 0x1,
 };

 /**
  * struct vidtv_psi_table_pmt_stream - A single stream in the PMT.
  * See ISO/IEC 13818-1 : 2000 p.46.
  */
 struct vidtv_psi_table_pmt_stream {
 	u8 type;
 	__be16 bitfield; /* reserved: 3, elementary_pid: 13 */
 	__be16 bitfield2; /*reserved: 4, zero: 2, desc_length: 10 */
 	struct vidtv_psi_desc *descriptor;
 	struct vidtv_psi_table_pmt_stream *next;
 } __packed;

 /**
  * struct vidtv_psi_table_pmt - The Program Map Table (PMT).
  * See ISO/IEC 13818-1 : 2000 p.46.
  */
 struct vidtv_psi_table_pmt {
 	struct vidtv_psi_table_header header;
 	__be16 bitfield; /* reserved:3, pcr_pid: 13 */
 	__be16 bitfield2; /* reserved: 4, zero: 2, desc_len: 10 */
 	struct vidtv_psi_desc *descriptor;
 	struct vidtv_psi_table_pmt_stream *stream;
 } __packed;

 /**
  * struct psi_write_args - Arguments for the PSI packetizer.
  * @dest_buf: The buffer to write into.
  * @from: PSI data to be copied.
  * @len: How much to write.
  * @dest_offset: where to start writing in the dest_buffer.
  * @pid: TS packet ID.
  * @new_psi_section: Set when starting a table section.
  * @continuity_counter: Incremented on every new packet.
  * @is_crc: Set when writing the CRC at the end.
  * @dest_buf_sz: The size of the dest_buffer
  * @crc: a pointer to store the crc for this chunk
  */
 struct psi_write_args {
 	void *dest_buf;
 	void *from;
 	size_t len;
 	u32 dest_offset;
 	u16 pid;
 	bool new_psi_section;
 	u8 *continuity_counter;
 	bool is_crc;
 	u32 dest_buf_sz;
 	u32 *crc;
 };

 /**
  * struct desc_write_args - Arguments in order to write a descriptor.
  * @dest_buf: The buffer to write into.
  * @dest_offset: where to start writing in the dest_buffer.
  * @desc: A pointer to the descriptor
  * @pid: TS packet ID.
  * @continuity_counter: Incremented on every new packet.
  * @dest_buf_sz: The size of the dest_buffer
  * @crc: a pointer to store the crc for this chunk
  */
 struct desc_write_args {
 	void *dest_buf;
 	u32 dest_offset;
 	struct vidtv_psi_desc *desc;
 	u16 pid;
 	u8 *continuity_counter;
 	u32 dest_buf_sz;
 	u32 *crc;
 };

 /**
  * struct crc32_write_args - Arguments in order to write the CRC at the end of
  * the PSI tables.
  * @dest_buf: The buffer to write into.
  * @dest_offset: where to start writing in the dest_buffer.
  * @crc: the CRC value to write
  * @pid: TS packet ID.
  * @continuity_counter: Incremented on every new packet.
  * @dest_buf_sz: The size of the dest_buffer
  */
 struct crc32_write_args {
 	void *dest_buf;
 	u32 dest_offset;
 	__be32 crc;
 	u16 pid;
 	u8 *continuity_counter;
 	u32 dest_buf_sz;
 };

 /**
  * struct header_write_args - Arguments in order to write the common table
  * header
  * @dest_buf: The buffer to write into.
  * @dest_offset: where to start writing in the dest_buffer.
  * @h: a pointer to the header.
  * @pid: TS packet ID.
  * @continuity_counter: Incremented on every new packet.
  * @dest_buf_sz: The size of the dest_buffer
  * @crc: a pointer to store the crc for this chunk
  */
 struct header_write_args {
 	void *dest_buf;
 	u32 dest_offset;
 	struct vidtv_psi_table_header *h;
 	u16 pid;
 	u8 *continuity_counter;
 	u32 dest_buf_sz;
 	u32 *crc;
 };

 struct vidtv_psi_desc_service *vidtv_psi_service_desc_init(struct vidtv_psi_desc *head,
 							   enum service_type service_type,
 							   char *service_name,
 							   char *provider_name);

 struct vidtv_psi_desc_registration
 *vidtv_psi_registration_desc_init(struct vidtv_psi_desc *head,
 				  __be32 format_id,
 				  u8 *additional_ident_info,
 				  u32 additional_info_len);

 struct vidtv_psi_table_pat_program
 *vidtv_psi_pat_program_init(struct vidtv_psi_table_pat_program *head,
 			    u16 service_id,
 			    u16 program_map_pid);

 struct vidtv_psi_table_pmt_stream*
 vidtv_psi_pmt_stream_init(struct vidtv_psi_table_pmt_stream *head,
 			  enum vidtv_psi_stream_types stream_type,
 			  u16 es_pid);

 struct vidtv_psi_table_pat *vidtv_psi_pat_table_init(u16 transport_stream_id);

 struct vidtv_psi_table_pmt *vidtv_psi_pmt_table_init(u16 program_number,
 						     u16 pcr_pid);

 struct vidtv_psi_table_sdt *vidtv_psi_sdt_table_init(u16 transport_stream_id);

 struct vidtv_psi_table_sdt_service*
 vidtv_psi_sdt_service_init(struct vidtv_psi_table_sdt_service *head,
 			   u16 service_id);

 void
 vidtv_psi_desc_destroy(struct vidtv_psi_desc *desc);

 void
 vidtv_psi_pat_program_destroy(struct vidtv_psi_table_pat_program *p);

 void
 vidtv_psi_pat_table_destroy(struct vidtv_psi_table_pat *p);

 void
 vidtv_psi_pmt_stream_destroy(struct vidtv_psi_table_pmt_stream *s);

 void
 vidtv_psi_pmt_table_destroy(struct vidtv_psi_table_pmt *pmt);

 void
 vidtv_psi_sdt_table_destroy(struct vidtv_psi_table_sdt *sdt);

 void
 vidtv_psi_sdt_service_destroy(struct vidtv_psi_table_sdt_service *service);

 /**
  * vidtv_psi_sdt_service_assign - Assigns the service loop to the SDT.
  * @sdt: The SDT to assign to.
  * @service: The service loop (one or more services)
  *
  * This will free the previous service loop in the table.
  * This will assign ownership of the service loop to the table, i.e. the table
  * will free this service loop when a call to its destroy function is made.
  */
 void
 vidtv_psi_sdt_service_assign(struct vidtv_psi_table_sdt *sdt,
 			     struct vidtv_psi_table_sdt_service *service);

 /**
  * vidtv_psi_desc_assign - Assigns a descriptor loop at some point
  * @to: Where to assign this descriptor loop to
  * @desc: The descriptor loop that will be assigned.
  *
  * This will free the loop in 'to', if any.
  */
 void vidtv_psi_desc_assign(struct vidtv_psi_desc **to,
 			   struct vidtv_psi_desc *desc);

 /**
  * vidtv_psi_pmt_desc_assign - Assigns a descriptor loop at some point in a PMT section.
  * @pmt: The PMT section that will contain the descriptor loop
  * @to: Where in the PMT to assign this descriptor loop to
  * @desc: The descriptor loop that will be assigned.
  *
  * This will free the loop in 'to', if any.
  * This will assign ownership of the loop to the table, i.e. the table
  * will free this loop when a call to its destroy function is made.
  */
 void vidtv_pmt_desc_assign(struct vidtv_psi_table_pmt *pmt,
 			   struct vidtv_psi_desc **to,
 			   struct vidtv_psi_desc *desc);

 /**
  * vidtv_psi_sdt_desc_assign - Assigns a descriptor loop at some point in a SDT.
  * @sdt: The SDT that will contain the descriptor loop
  * @to: Where in the PMT to assign this descriptor loop to
  * @desc: The descriptor loop that will be assigned.
  *
  * This will free the loop in 'to', if any.
  * This will assign ownership of the loop to the table, i.e. the table
  * will free this loop when a call to its destroy function is made.
  */
 void vidtv_sdt_desc_assign(struct vidtv_psi_table_sdt *sdt,
 			   struct vidtv_psi_desc **to,
 			   struct vidtv_psi_desc *desc);

 /**
  * vidtv_psi_pat_program_assign - Assigns the program loop to the PAT.
  * @pat: The PAT to assign to.
  * @p: The program loop (one or more programs)
  *
  * This will free the previous program loop in the table.
  * This will assign ownership of the program loop to the table, i.e. the table
  * will free this program loop when a call to its destroy function is made.
  */
 void vidtv_psi_pat_program_assign(struct vidtv_psi_table_pat *pat,
 				  struct vidtv_psi_table_pat_program *p);

 /**
  * vidtv_psi_pmt_stream_assign - Assigns the stream loop to the PAT.
  * @pmt: The PMT to assign to.
  * @s: The stream loop (one or more streams)
  *
  * This will free the previous stream loop in the table.
  * This will assign ownership of the stream loop to the table, i.e. the table
  * will free this stream loop when a call to its destroy function is made.
  */
 void vidtv_psi_pmt_stream_assign(struct vidtv_psi_table_pmt *pmt,
 				 struct vidtv_psi_table_pmt_stream *s);

 struct vidtv_psi_desc *vidtv_psi_desc_clone(struct vidtv_psi_desc *desc);

 /**
  * vidtv_psi_create_sec_for_each_pat_entry - Create a PMT section for each
  * program found in the PAT
  * @pat: The PAT to look for programs.
  * @s: The stream loop (one or more streams)
  * @pcr_pid: packet ID for the PCR to be used for the program described in this
  * PMT section
  */
 struct vidtv_psi_table_pmt**
 vidtv_psi_pmt_create_sec_for_each_pat_entry(struct vidtv_psi_table_pat *pat, u16 pcr_pid);

 /**
  * vidtv_psi_pmt_get_pid - Get the TS PID for a PMT section.
  * @section: The PMT section whose PID we want to retrieve.
  * @pat: The PAT table to look into.
  *
  * Returns: the TS PID for 'section'
  */
 u16 vidtv_psi_pmt_get_pid(struct vidtv_psi_table_pmt *section,
 			  struct vidtv_psi_table_pat *pat);

 /**
  * vidtv_psi_pat_table_update_sec_len - Recompute and update the PAT section length.
  * @pat: The PAT whose length is to be updated.
  *
  * This will traverse the table and accumulate the length of its components,
  * which is then used to replace the 'section_length' field.
  *
  * If section_length > MAX_SECTION_LEN, the operation fails.
  */
 void vidtv_psi_pat_table_update_sec_len(struct vidtv_psi_table_pat *pat);

 /**
  * vidtv_psi_pmt_table_update_sec_len - Recompute and update the PMT section length.
  * @pmt: The PMT whose length is to be updated.
  *
  * This will traverse the table and accumulate the length of its components,
  * which is then used to replace the 'section_length' field.
  *
  * If section_length > MAX_SECTION_LEN, the operation fails.
  */
 void vidtv_psi_pmt_table_update_sec_len(struct vidtv_psi_table_pmt *pmt);

 /**
  * vidtv_psi_sdt_table_update_sec_len - Recompute and update the SDT section length.
  * @sdt: The SDT whose length is to be updated.
  *
  * This will traverse the table and accumulate the length of its components,
  * which is then used to replace the 'section_length' field.
  *
  * If section_length > MAX_SECTION_LEN, the operation fails.
  */
 void vidtv_psi_sdt_table_update_sec_len(struct vidtv_psi_table_sdt *sdt);

 /**
  * struct vidtv_psi_pat_write_args - Arguments for writing a PAT table
  * @buf: The destination buffer.
  * @offset: The offset into the destination buffer.
  * @pat: A pointer to the PAT.
  * @buf_sz: The size of the destination buffer.
  * @continuity_counter: A pointer to the CC. Incremented on every new packet.
  *
  */
 struct vidtv_psi_pat_write_args {
 	char *buf;
 	u32 offset;
 	struct vidtv_psi_table_pat *pat;
 	u32 buf_sz;
 	u8 *continuity_counter;
 };

 /**
  * vidtv_psi_pat_write_into - Write PAT as MPEG-TS packets into a buffer.
  * @args: An instance of struct vidtv_psi_pat_write_args
  *
  * This function writes the MPEG TS packets for a PAT table into a buffer.
  * Calling code will usually generate the PAT via a call to its init function
  * and thus is responsible for freeing it.
  *
  * Return: The number of bytes written into the buffer. This is NOT
  * equal to the size of the PAT, since more space is needed for TS headers during TS
  * encapsulation.
  */
 u32 vidtv_psi_pat_write_into(struct vidtv_psi_pat_write_args args);

 /**
  * struct vidtv_psi_sdt_write_args - Arguments for writing a SDT table
  * @buf: The destination buffer.
  * @offset: The offset into the destination buffer.
  * @sdt: A pointer to the SDT.
  * @buf_sz: The size of the destination buffer.
  * @continuity_counter: A pointer to the CC. Incremented on every new packet.
  *
  */

 struct vidtv_psi_sdt_write_args {
 	char *buf;
 	u32 offset;
 	struct vidtv_psi_table_sdt *sdt;
 	u32 buf_sz;
 	u8 *continuity_counter;
 };

 /**
  * vidtv_psi_sdt_write_into - Write SDT as MPEG-TS packets into a buffer.
  * @args: an instance of struct vidtv_psi_sdt_write_args
  *
  * This function writes the MPEG TS packets for a SDT table into a buffer.
  * Calling code will usually generate the SDT via a call to its init function
  * and thus is responsible for freeing it.
  *
  * Return: The number of bytes written into the buffer. This is NOT
  * equal to the size of the SDT, since more space is needed for TS headers during TS
  * encapsulation.
  */
 u32 vidtv_psi_sdt_write_into(struct vidtv_psi_sdt_write_args args);

 /**
  * struct vidtv_psi_pmt_write_args - Arguments for writing a PMT section
  * @buf: The destination buffer.
  * @offset: The offset into the destination buffer.
  * @pmt: A pointer to the PMT.
  * @buf_sz: The size of the destination buffer.
  * @continuity_counter: A pointer to the CC. Incremented on every new packet.
  *
  */
 struct vidtv_psi_pmt_write_args {
 	char *buf;
 	u32 offset;
 	struct vidtv_psi_table_pmt *pmt;
 	u16 pid;
 	u32 buf_sz;
 	u8 *continuity_counter;
 	u16 pcr_pid;
 };

 /**
  * vidtv_psi_pmt_write_into - Write PMT as MPEG-TS packets into a buffer.
  * @args: an instance of struct vidtv_psi_pmt_write_args
  *
  * This function writes the MPEG TS packets for a PMT section into a buffer.
  * Calling code will usually generate the PMT section via a call to its init function
  * and thus is responsible for freeing it.
  *
  * Return: The number of bytes written into the buffer. This is NOT
  * equal to the size of the PMT section, since more space is needed for TS headers
  * during TS encapsulation.
  */
 u32 vidtv_psi_pmt_write_into(struct vidtv_psi_pmt_write_args args);

 /**
  * vidtv_psi_find_pmt_sec - Finds the PMT section for 'program_num'
  * @pmt_sections: The sections to look into.
  * @nsections: The number of sections.
  * @program_num: The 'program_num' from PAT pointing to a PMT section.
  *
  * Return: A pointer to the PMT, if found, or NULL.
  */
 struct vidtv_psi_table_pmt *vidtv_psi_find_pmt_sec(struct vidtv_psi_table_pmt **pmt_sections,
 						   u16 nsections,
 						   u16 program_num);

 u16 vidtv_psi_get_pat_program_pid(struct vidtv_psi_table_pat_program *p);
 u16 vidtv_psi_pmt_stream_get_elem_pid(struct vidtv_psi_table_pmt_stream *s);

 #endif // VIDTV_PSI_H
	/* SPDX-License-Identifier: GPL-2.0 */
	/*
	* This file contains the logic to work with MPEG Program-Specific Information.
	* These are defined both in ISO/IEC 13818-1 (systems) and ETSI EN 300 468.
	* PSI is carried in the form of table structures, and although each table might
	* technically be broken into one or more sections, we do not do this here,
	* hence 'table' and 'section' are interchangeable for vidtv.
	*
	* This code currently supports three tables: PAT, PMT and SDT. These are the
	* bare minimum to get userspace to recognize our MPEG transport stream. It can
	* be extended to support more PSI tables in the future.
	*
	* Copyright (C) 2020 Daniel W. S. Almeida
	*/

	#ifndef VIDTV_PSI_H
	#define VIDTV_PSI_H

	#include <linux/types.h>
	#include <asm/byteorder.h>

	/*
	* all section lengths start immediately after the 'section_length' field
	* see ISO/IEC 13818-1 : 2000 and ETSI EN 300 468 V 1.10.1 for
	* reference
	*/
	#define PAT_LEN_UNTIL_LAST_SECTION_NUMBER 5
	#define PMT_LEN_UNTIL_PROGRAM_INFO_LENGTH 9
	#define SDT_LEN_UNTIL_RESERVED_FOR_FUTURE_USE 8
	#define MAX_SECTION_LEN 1021
	#define VIDTV_PAT_PID 0 /* mandated by the specs */
	#define VIDTV_SDT_PID 0x0011 /* mandated by the specs */

	enum vidtv_psi_descriptors {
	REGISTRATION_DESCRIPTOR = 0x05, /* See ISO/IEC 13818-1 section 2.6.8 */
	SERVICE_DESCRIPTOR = 0x48, /* See ETSI EN 300 468 section 6.2.33 */
	};

	enum vidtv_psi_stream_types {
	STREAM_PRIVATE_DATA = 0x06, /* see ISO/IEC 13818-1 2000 p. 48 */
	};

	/**
	* struct vidtv_psi_desc - A generic PSI descriptor type.
	* The descriptor length is an 8-bit field specifying the total number of bytes of the data portion
	* of the descriptor following the byte defining the value of this field.
	*/
	struct vidtv_psi_desc {
	struct vidtv_psi_desc *next;
	u8 type;
	u8 length;
	u8 data[];
	} __packed;

	/**
	* struct vidtv_psi_desc_service - Service descriptor.
	* See ETSI EN 300 468 section 6.2.33.
	*/
	struct vidtv_psi_desc_service {
	struct vidtv_psi_desc *next;
	u8 type;
	u8 length;

	u8 service_type;
	u8 provider_name_len;
	char *provider_name;
	u8 service_name_len;
	char *service_name;
	} __packed;

	/**
	* struct vidtv_psi_desc_registration - A registration descriptor.
	* See ISO/IEC 13818-1 section 2.6.8
	*/
	struct vidtv_psi_desc_registration {
	struct vidtv_psi_desc *next;
	u8 type;
	u8 length;

	/*
	* The format_identifier is a 32-bit value obtained from a Registration
	* Authority as designated by ISO/IEC JTC 1/SC 29.
	*/
	__be32 format_id;
	/*
	* The meaning of additional_identification_info bytes, if any, are
	* defined by the assignee of that format_identifier, and once defined
	* they shall not change.
	*/
	u8 additional_identification_info[];
	} __packed;

	/**
	* struct vidtv_psi_table_header - A header that is present for all PSI tables.
	*/
	struct vidtv_psi_table_header {
	u8 table_id;

	__be16 bitfield; /* syntax: 1, zero: 1, one: 2, section_length: 13 */

	__be16 id; /* TS ID */
	u8 current_next:1;
	u8 version:5;
	u8 one2:2;
	u8 section_id; /* section_number */
	u8 last_section; /* last_section_number */
	} __packed;

	/**
	* struct vidtv_psi_table_pat_program - A single program in the PAT
	* See ISO/IEC 13818-1 : 2000 p.43
	*/
	struct vidtv_psi_table_pat_program {
	__be16 service_id;
	__be16 bitfield; /* reserved: 3, program_map_pid/network_pid: 13 */
	struct vidtv_psi_table_pat_program *next;
	} __packed;

	/**
	* struct vidtv_psi_table_pat - The Program Allocation Table (PAT)
	* See ISO/IEC 13818-1 : 2000 p.43
	*/
	struct vidtv_psi_table_pat {
	struct vidtv_psi_table_header header;
	u16 programs; /* Included by libdvbv5, not part of the table and not actually serialized */
	struct vidtv_psi_table_pat_program *program;
	} __packed;

	/**
	* struct vidtv_psi_table_sdt_service - Represents a service in the SDT.
	* see ETSI EN 300 468 v1.15.1 section 5.2.3.
	*/
	struct vidtv_psi_table_sdt_service {
	__be16 service_id;
	u8 EIT_present_following:1;
	u8 EIT_schedule:1;
	u8 reserved:6;
	__be16 bitfield; /* running_status: 3, free_ca:1, desc_loop_len:12 */
	struct vidtv_psi_desc *descriptor;
	struct vidtv_psi_table_sdt_service *next;
	} __packed;

	/**
	* struct vidtv_psi_table_sdt - Represents the Service Description Table
	* see ETSI EN 300 468 v1.15.1 section 5.2.3.
	*/

	struct vidtv_psi_table_sdt {
	struct vidtv_psi_table_header header;
	__be16 network_id; /* original_network_id */
	u8 reserved;
	struct vidtv_psi_table_sdt_service *service;
	} __packed;

	/**
	* enum service_running_status - Status of a SDT service.
	* see ETSI EN 300 468 v1.15.1 section 5.2.3 table 6.
	*/
	enum service_running_status {
	RUNNING = 0x4,
	};

	/**
	* enum service_type - The type of a SDT service.
	* see ETSI EN 300 468 v1.15.1 section 6.2.33, table 81.
	*/
	enum service_type {
	/* see ETSI EN 300 468 v1.15.1 p. 77 */
	DIGITAL_TELEVISION_SERVICE = 0x1,
	};

	/**
	* struct vidtv_psi_table_pmt_stream - A single stream in the PMT.
	* See ISO/IEC 13818-1 : 2000 p.46.
	*/
	struct vidtv_psi_table_pmt_stream {
	u8 type;
	__be16 bitfield; /* reserved: 3, elementary_pid: 13 */
	__be16 bitfield2; /reserved: 4, zero: 2, desc_length: 10 /
	struct vidtv_psi_desc *descriptor;
	struct vidtv_psi_table_pmt_stream *next;
	} __packed;

	/**
	* struct vidtv_psi_table_pmt - The Program Map Table (PMT).
	* See ISO/IEC 13818-1 : 2000 p.46.
	*/
	struct vidtv_psi_table_pmt {
	struct vidtv_psi_table_header header;
	__be16 bitfield; /* reserved:3, pcr_pid: 13 */
	__be16 bitfield2; /* reserved: 4, zero: 2, desc_len: 10 */
	struct vidtv_psi_desc *descriptor;
	struct vidtv_psi_table_pmt_stream *stream;
	} __packed;

	/**
	* struct psi_write_args - Arguments for the PSI packetizer.
	* @dest_buf: The buffer to write into.
	* @from: PSI data to be copied.
	* @len: How much to write.
	* @dest_offset: where to start writing in the dest_buffer.
	* @pid: TS packet ID.
	* @new_psi_section: Set when starting a table section.
	* @continuity_counter: Incremented on every new packet.
	* @is_crc: Set when writing the CRC at the end.
	* @dest_buf_sz: The size of the dest_buffer
	* @crc: a pointer to store the crc for this chunk
	*/
	struct psi_write_args {
	void *dest_buf;
	void *from;
	size_t len;
	u32 dest_offset;
	u16 pid;
	bool new_psi_section;
	u8 *continuity_counter;
	bool is_crc;
	u32 dest_buf_sz;
	u32 *crc;
	};

	/**
	* struct desc_write_args - Arguments in order to write a descriptor.
	* @dest_buf: The buffer to write into.
	* @dest_offset: where to start writing in the dest_buffer.
	* @desc: A pointer to the descriptor
	* @pid: TS packet ID.
	* @continuity_counter: Incremented on every new packet.
	* @dest_buf_sz: The size of the dest_buffer
	* @crc: a pointer to store the crc for this chunk
	*/
	struct desc_write_args {
	void *dest_buf;
	u32 dest_offset;
	struct vidtv_psi_desc *desc;
	u16 pid;
	u8 *continuity_counter;
	u32 dest_buf_sz;
	u32 *crc;
	};

	/**
	* struct crc32_write_args - Arguments in order to write the CRC at the end of
	* the PSI tables.
	* @dest_buf: The buffer to write into.
	* @dest_offset: where to start writing in the dest_buffer.
	* @crc: the CRC value to write
	* @pid: TS packet ID.
	* @continuity_counter: Incremented on every new packet.
	* @dest_buf_sz: The size of the dest_buffer
	*/
	struct crc32_write_args {
	void *dest_buf;
	u32 dest_offset;
	__be32 crc;
	u16 pid;
	u8 *continuity_counter;
	u32 dest_buf_sz;
	};

	/**
	* struct header_write_args - Arguments in order to write the common table
	* header
	* @dest_buf: The buffer to write into.
	* @dest_offset: where to start writing in the dest_buffer.
	* @h: a pointer to the header.
	* @pid: TS packet ID.
	* @continuity_counter: Incremented on every new packet.
	* @dest_buf_sz: The size of the dest_buffer
	* @crc: a pointer to store the crc for this chunk
	*/
	struct header_write_args {
	void *dest_buf;
	u32 dest_offset;
	struct vidtv_psi_table_header *h;
	u16 pid;
	u8 *continuity_counter;
	u32 dest_buf_sz;
	u32 *crc;
	};

	struct vidtv_psi_desc_service vidtv_psi_service_desc_init(struct vidtv_psi_desc head,
	enum service_type service_type,
	char *service_name,
	char *provider_name);

	struct vidtv_psi_desc_registration
	vidtv_psi_registration_desc_init(struct vidtv_psi_desc head,
	__be32 format_id,
	u8 *additional_ident_info,
	u32 additional_info_len);

	struct vidtv_psi_table_pat_program
	vidtv_psi_pat_program_init(struct vidtv_psi_table_pat_program head,
	u16 service_id,
	u16 program_map_pid);

	struct vidtv_psi_table_pmt_stream*
	vidtv_psi_pmt_stream_init(struct vidtv_psi_table_pmt_stream *head,
	enum vidtv_psi_stream_types stream_type,
	u16 es_pid);

	struct vidtv_psi_table_pat *vidtv_psi_pat_table_init(u16 transport_stream_id);

	struct vidtv_psi_table_pmt *vidtv_psi_pmt_table_init(u16 program_number,
	u16 pcr_pid);

	struct vidtv_psi_table_sdt *vidtv_psi_sdt_table_init(u16 transport_stream_id);

	struct vidtv_psi_table_sdt_service*
	vidtv_psi_sdt_service_init(struct vidtv_psi_table_sdt_service *head,
	u16 service_id);

	void
	vidtv_psi_desc_destroy(struct vidtv_psi_desc *desc);

	void
	vidtv_psi_pat_program_destroy(struct vidtv_psi_table_pat_program *p);

	void
	vidtv_psi_pat_table_destroy(struct vidtv_psi_table_pat *p);

	void
	vidtv_psi_pmt_stream_destroy(struct vidtv_psi_table_pmt_stream *s);

	void
	vidtv_psi_pmt_table_destroy(struct vidtv_psi_table_pmt *pmt);

	void
	vidtv_psi_sdt_table_destroy(struct vidtv_psi_table_sdt *sdt);

	void
	vidtv_psi_sdt_service_destroy(struct vidtv_psi_table_sdt_service *service);

	/**
	* vidtv_psi_sdt_service_assign - Assigns the service loop to the SDT.
	* @sdt: The SDT to assign to.
	* @service: The service loop (one or more services)
	*
	* This will free the previous service loop in the table.
	* This will assign ownership of the service loop to the table, i.e. the table
	* will free this service loop when a call to its destroy function is made.
	*/
	void
	vidtv_psi_sdt_service_assign(struct vidtv_psi_table_sdt *sdt,
	struct vidtv_psi_table_sdt_service *service);

	/**
	* vidtv_psi_desc_assign - Assigns a descriptor loop at some point
	* @to: Where to assign this descriptor loop to
	* @desc: The descriptor loop that will be assigned.
	*
	* This will free the loop in 'to', if any.
	*/
	void vidtv_psi_desc_assign(struct vidtv_psi_desc **to,
	struct vidtv_psi_desc *desc);

	/**
	* vidtv_psi_pmt_desc_assign - Assigns a descriptor loop at some point in a PMT section.
	* @pmt: The PMT section that will contain the descriptor loop
	* @to: Where in the PMT to assign this descriptor loop to
	* @desc: The descriptor loop that will be assigned.
	*
	* This will free the loop in 'to', if any.
	* This will assign ownership of the loop to the table, i.e. the table
	* will free this loop when a call to its destroy function is made.
	*/
	void vidtv_pmt_desc_assign(struct vidtv_psi_table_pmt *pmt,
	struct vidtv_psi_desc **to,
	struct vidtv_psi_desc *desc);

	/**
	* vidtv_psi_sdt_desc_assign - Assigns a descriptor loop at some point in a SDT.
	* @sdt: The SDT that will contain the descriptor loop
	* @to: Where in the PMT to assign this descriptor loop to
	* @desc: The descriptor loop that will be assigned.
	*
	* This will free the loop in 'to', if any.
	* This will assign ownership of the loop to the table, i.e. the table
	* will free this loop when a call to its destroy function is made.
	*/
	void vidtv_sdt_desc_assign(struct vidtv_psi_table_sdt *sdt,
	struct vidtv_psi_desc **to,
	struct vidtv_psi_desc *desc);

	/**
	* vidtv_psi_pat_program_assign - Assigns the program loop to the PAT.
	* @pat: The PAT to assign to.
	* @p: The program loop (one or more programs)
	*
	* This will free the previous program loop in the table.
	* This will assign ownership of the program loop to the table, i.e. the table
	* will free this program loop when a call to its destroy function is made.
	*/
	void vidtv_psi_pat_program_assign(struct vidtv_psi_table_pat *pat,
	struct vidtv_psi_table_pat_program *p);

	/**
	* vidtv_psi_pmt_stream_assign - Assigns the stream loop to the PAT.
	* @pmt: The PMT to assign to.
	* @s: The stream loop (one or more streams)
	*
	* This will free the previous stream loop in the table.
	* This will assign ownership of the stream loop to the table, i.e. the table
	* will free this stream loop when a call to its destroy function is made.
	*/
	void vidtv_psi_pmt_stream_assign(struct vidtv_psi_table_pmt *pmt,
	struct vidtv_psi_table_pmt_stream *s);

	struct vidtv_psi_desc vidtv_psi_desc_clone(struct vidtv_psi_desc desc);

	/**
	* vidtv_psi_create_sec_for_each_pat_entry - Create a PMT section for each
	* program found in the PAT
	* @pat: The PAT to look for programs.
	* @s: The stream loop (one or more streams)
	* @pcr_pid: packet ID for the PCR to be used for the program described in this
	* PMT section
	*/
	struct vidtv_psi_table_pmt**
	vidtv_psi_pmt_create_sec_for_each_pat_entry(struct vidtv_psi_table_pat *pat, u16 pcr_pid);

	/**
	* vidtv_psi_pmt_get_pid - Get the TS PID for a PMT section.
	* @section: The PMT section whose PID we want to retrieve.
	* @pat: The PAT table to look into.
	*
	* Returns: the TS PID for 'section'
	*/
	u16 vidtv_psi_pmt_get_pid(struct vidtv_psi_table_pmt *section,
	struct vidtv_psi_table_pat *pat);

	/**
	* vidtv_psi_pat_table_update_sec_len - Recompute and update the PAT section length.
	* @pat: The PAT whose length is to be updated.
	*
	* This will traverse the table and accumulate the length of its components,
	* which is then used to replace the 'section_length' field.
	*
	* If section_length > MAX_SECTION_LEN, the operation fails.
	*/
	void vidtv_psi_pat_table_update_sec_len(struct vidtv_psi_table_pat *pat);

	/**
	* vidtv_psi_pmt_table_update_sec_len - Recompute and update the PMT section length.
	* @pmt: The PMT whose length is to be updated.
	*
	* This will traverse the table and accumulate the length of its components,
	* which is then used to replace the 'section_length' field.
	*
	* If section_length > MAX_SECTION_LEN, the operation fails.
	*/
	void vidtv_psi_pmt_table_update_sec_len(struct vidtv_psi_table_pmt *pmt);

	/**
	* vidtv_psi_sdt_table_update_sec_len - Recompute and update the SDT section length.
	* @sdt: The SDT whose length is to be updated.
	*
	* This will traverse the table and accumulate the length of its components,
	* which is then used to replace the 'section_length' field.
	*
	* If section_length > MAX_SECTION_LEN, the operation fails.
	*/
	void vidtv_psi_sdt_table_update_sec_len(struct vidtv_psi_table_sdt *sdt);

	/**
	* struct vidtv_psi_pat_write_args - Arguments for writing a PAT table
	* @buf: The destination buffer.
	* @offset: The offset into the destination buffer.
	* @pat: A pointer to the PAT.
	* @buf_sz: The size of the destination buffer.
	* @continuity_counter: A pointer to the CC. Incremented on every new packet.
	*
	*/
	struct vidtv_psi_pat_write_args {
	char *buf;
	u32 offset;
	struct vidtv_psi_table_pat *pat;
	u32 buf_sz;
	u8 *continuity_counter;
	};

	/**
	* vidtv_psi_pat_write_into - Write PAT as MPEG-TS packets into a buffer.
	* @args: An instance of struct vidtv_psi_pat_write_args
	*
	* This function writes the MPEG TS packets for a PAT table into a buffer.
	* Calling code will usually generate the PAT via a call to its init function
	* and thus is responsible for freeing it.
	*
	* Return: The number of bytes written into the buffer. This is NOT
	* equal to the size of the PAT, since more space is needed for TS headers during TS
	* encapsulation.
	*/
	u32 vidtv_psi_pat_write_into(struct vidtv_psi_pat_write_args args);

	/**
	* struct vidtv_psi_sdt_write_args - Arguments for writing a SDT table
	* @buf: The destination buffer.
	* @offset: The offset into the destination buffer.
	* @sdt: A pointer to the SDT.
	* @buf_sz: The size of the destination buffer.
	* @continuity_counter: A pointer to the CC. Incremented on every new packet.
	*
	*/

	struct vidtv_psi_sdt_write_args {
	char *buf;
	u32 offset;
	struct vidtv_psi_table_sdt *sdt;
	u32 buf_sz;
	u8 *continuity_counter;
	};

	/**
	* vidtv_psi_sdt_write_into - Write SDT as MPEG-TS packets into a buffer.
	* @args: an instance of struct vidtv_psi_sdt_write_args
	*
	* This function writes the MPEG TS packets for a SDT table into a buffer.
	* Calling code will usually generate the SDT via a call to its init function
	* and thus is responsible for freeing it.
	*
	* Return: The number of bytes written into the buffer. This is NOT
	* equal to the size of the SDT, since more space is needed for TS headers during TS
	* encapsulation.
	*/
	u32 vidtv_psi_sdt_write_into(struct vidtv_psi_sdt_write_args args);

	/**
	* struct vidtv_psi_pmt_write_args - Arguments for writing a PMT section
	* @buf: The destination buffer.
	* @offset: The offset into the destination buffer.
	* @pmt: A pointer to the PMT.
	* @buf_sz: The size of the destination buffer.
	* @continuity_counter: A pointer to the CC. Incremented on every new packet.
	*
	*/
	struct vidtv_psi_pmt_write_args {
	char *buf;
	u32 offset;
	struct vidtv_psi_table_pmt *pmt;
	u16 pid;
	u32 buf_sz;
	u8 *continuity_counter;
	u16 pcr_pid;
	};

	/**
	* vidtv_psi_pmt_write_into - Write PMT as MPEG-TS packets into a buffer.
	* @args: an instance of struct vidtv_psi_pmt_write_args
	*
	* This function writes the MPEG TS packets for a PMT section into a buffer.
	* Calling code will usually generate the PMT section via a call to its init function
	* and thus is responsible for freeing it.
	*
	* Return: The number of bytes written into the buffer. This is NOT
	* equal to the size of the PMT section, since more space is needed for TS headers
	* during TS encapsulation.
	*/
	u32 vidtv_psi_pmt_write_into(struct vidtv_psi_pmt_write_args args);

	/**
	* vidtv_psi_find_pmt_sec - Finds the PMT section for 'program_num'
	* @pmt_sections: The sections to look into.
	* @nsections: The number of sections.
	* @program_num: The 'program_num' from PAT pointing to a PMT section.
	*
	* Return: A pointer to the PMT, if found, or NULL.
	*/
	struct vidtv_psi_table_pmt vidtv_psi_find_pmt_sec(struct vidtv_psi_table_pmt *pmt_sections,
	u16 nsections,
	u16 program_num);

	u16 vidtv_psi_get_pat_program_pid(struct vidtv_psi_table_pat_program *p);
	u16 vidtv_psi_pmt_stream_get_elem_pid(struct vidtv_psi_table_pmt_stream *s);

	#endif // VIDTV_PSI_H