1 files changed, 195 insertions, 0 deletions
diff --git a/lib/libucsi/transport_packet.h b/lib/libucsi/transport_packet.h
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+/*
+ * section and descriptor parser
+ *
+ * Copyright (C) 2005 Andrew de Quincey (adq_dvb@lidskialf.net)
+ *
+ * This library 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 library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#ifndef _UCSI_TRANSPORT_PACKET_H
+#define _UCSI_TRANSPORT_PACKET_H 1
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include <stdint.h>
+#include "descriptor.h"
+
+#define TRANSPORT_PACKET_LENGTH 188
+#define TRANSPORT_PACKET_SYNC   0x47
+#define TRANSPORT_MAX_PIDS      0x2000
+#define TRANSPORT_NULL_PID      0x1fff
+
+
+/**
+ * Enumeration of adaptation field control values.
+ */
+enum transport_adaptation_field_control {
+	transport_adaptation_field_control_reserved		= 0x00,
+	transport_adaptation_field_control_payload_only		= 0x01,
+	transport_adaptation_field_control_adaptation_only	= 0x02,
+	transport_adaptation_field_control_adaptation_payload	= 0x03,
+};
+
+/**
+ * Enumeration of scrambling control values.
+ */
+enum transport_scrambling_control {
+	transport_scrambling_control_unscrambled   		= 0x00,
+	transport_scrambling_control_user_1			= 0x01,
+	transport_scrambling_control_user_2			= 0x02,
+	transport_scrambling_control_user_3			= 0x03,
+};
+
+/**
+ * Enumeration of adaptation flags.
+ */
+enum transport_adaptation_flags {
+	transport_adaptation_flag_discontinuity			= 0x80,
+	transport_adaptation_flag_random_access			= 0x40,
+	transport_adaptation_flag_es_priority			= 0x20,
+	transport_adaptation_flag_pcr				= 0x10,
+	transport_adaptation_flag_opcr				= 0x08,
+	transport_adaptation_flag_splicing_point		= 0x04,
+	transport_adaptation_flag_private_data			= 0x02,
+	transport_adaptation_flag_extension			= 0x01,
+};
+
+/**
+ * Enumeration of adaptation extension flags.
+ */
+enum transport_adaptation_extension_flags {
+	transport_adaptation_extension_flag_ltw			= 0x80,
+	transport_adaptation_extension_flag_piecewise_rate	= 0x40,
+	transport_adaptation_extension_flag_seamless_splice	= 0x20,
+};
+
+/**
+ * Enumeration of flags controlling which values to extract using the
+ * transport_packet_values_extract() function.
+ */
+enum transport_value {
+	/* normal adaptation */
+	transport_value_pcr					= 0x0001,
+	transport_value_opcr					= 0x0002,
+	transport_value_splice_countdown			= 0x0004,
+	transport_value_private_data				= 0x0008,
+
+	/* extension adaptation */
+	transport_value_ltw					= 0x0100,
+	transport_value_piecewise_rate				= 0x0200,
+	transport_value_seamless_splice				= 0x0400,
+};
+
+/**
+ * Structure describing a transport packet header.
+ */
+struct transport_packet {
+	uint8_t sync_byte;
+  EBIT4(uint8_t transport_error_indicator 	: 1; ,
+	uint8_t payload_unit_start_indicator	: 1; ,
+	uint8_t transport_priority		: 1; ,
+	uint8_t pid_hi				: 5; );
+	uint8_t pid_lo;
+  EBIT3(uint8_t transport_scrambling_control	: 2; ,
+	uint8_t adaptation_field_control	: 2; ,
+	uint8_t continuity_counter		: 4; );
+	/* values */
+} __ucsi_packed;
+
+/**
+ * Structure to extract values into using the transport_packet_values_extract()
+ * function.
+ */
+struct transport_values {
+	enum transport_adaptation_flags flags; 	/* always extracted */
+	uint8_t *payload;     			/* always extracted */
+	uint16_t payload_length;    		/* always extracted */
+
+	uint64_t pcr;
+	uint64_t opcr;
+	uint8_t  splice_countdown;
+	uint8_t private_data_length;
+	uint8_t *private_data;
+	uint16_t ltw_offset;
+	uint32_t piecewise_rate;
+	uint8_t splice_type;
+	uint64_t dts_next_au;
+};
+
+/**
+ * Extract the PID from a transport packet.
+ *
+ * @param pkt The packet.
+ * @return The PID.
+ */
+static inline int transport_packet_pid(struct transport_packet *pkt)
+{
+	return (pkt->pid_hi << 8) | (pkt->pid_lo);
+}
+
+/**
+ * Process a buffer into a transport packet.
+ *
+ * @param buf Raw buffer. Note, this function assumes there are 188 bytes available.
+ * @return transport_packet pointer, or NULL on error.
+ */
+static inline struct transport_packet *transport_packet_init(unsigned char *buf)
+{
+	struct transport_packet *pkt = (struct transport_packet*) buf;
+
+	if (pkt->sync_byte != TRANSPORT_PACKET_SYNC)
+		return NULL;
+
+	if (transport_packet_pid(pkt) >= TRANSPORT_MAX_PIDS)
+		return NULL;
+
+	return pkt;
+}
+
+/**
+ * Check the continuity counter for a packet in a PID stream.
+ *
+ * @param pkt transport_packet to check.
+ * @param discontinuity_indicator Set to 1 if the packet's discontinuity_indicator flag is set.
+ * @param cstate Pointer to a single 8 bit character, used to store state for validating
+ * continuity. To initialise the state, simply set it to 0 before the first call.
+ * @return 0 if the continuity was correct, or nonzero on error. cstate will not be updated on error,
+ * it is up to the caller to clear it to accept the next packet.
+ */
+extern int transport_packet_continuity_check(struct transport_packet *pkt,
+					     int discontinuity_indicator, unsigned char *cstate);
+
+/**
+ * Extract selected fields from a transport packet.
+ *
+ * @param pkt The packet.
+ * @param out Destination structure for values.
+ * @param extract Orred bitmask of enum transport_value - tells it what fields
+ * to extract if they are available.
+ * @return < 0 => error. Otherwise, an orred bitmask of enum transport_value
+ * telling you what fields were successfully extracted.
+ */
+extern int transport_packet_values_extract(struct transport_packet *pkt,
+					   struct transport_values *out,
+					   enum transport_value extract);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif