[RFC PATCH 1/2] Initial version of the RDS-decoder library Signed-off-by: Konke Radlow <kradlow@xxxxxxxxx>

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---
 Makefile.am                     |    3 +-
 configure.ac                    |   10 +-
 lib/libv4l2rds/Makefile.am      |   11 +
 lib/libv4l2rds/libv4l2rds.c     |  871 +++++++++++++++++++++++++++++++++++++++
 lib/libv4l2rds/libv4l2rds.pc.in |   11 +
 5 files changed, 904 insertions(+), 2 deletions(-)
 create mode 100644 lib/libv4l2rds/Makefile.am
 create mode 100644 lib/libv4l2rds/libv4l2rds.c
 create mode 100644 lib/libv4l2rds/libv4l2rds.pc.in

diff --git a/Makefile.am b/Makefile.am
index b7b356c..6707f5f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5,7 +5,8 @@ SUBDIRS = \
 	lib/libv4lconvert \
 	lib/libv4l2 \
 	lib/libv4l1 \
-	lib/libdvbv5
+	lib/libdvbv5 \
+	lib/libv4l2rds
 
 if WITH_V4LUTILS
 SUBDIRS += \
diff --git a/configure.ac b/configure.ac
index 8ddcc9d..1d7eb29 100644
--- a/configure.ac
+++ b/configure.ac
@@ -14,6 +14,7 @@ AC_CONFIG_FILES([Makefile
 	lib/libv4l2/Makefile
 	lib/libv4l1/Makefile
 	lib/libdvbv5/Makefile
+	lib/libv4l2rds/Makefile
 
 	utils/libv4l2util/Makefile
 	utils/libmedia_dev/Makefile
@@ -36,6 +37,7 @@ AC_CONFIG_FILES([Makefile
 	lib/libv4l1/libv4l1.pc
 	lib/libv4l2/libv4l2.pc
 	lib/libdvbv5/libdvbv5.pc
+	lib/libv4l2rds/libv4l2rds.pc
 ])
 
 AM_INIT_AUTOMAKE([1.9 no-dist-gzip dist-bzip2 -Wno-portability]) # 1.10 is needed for target_LIBTOOLFLAGS
@@ -146,13 +148,17 @@ AC_ARG_WITH(libv4l2subdir, AS_HELP_STRING(--with-libv4l2subdir=DIR,set libv4l2 l
 AC_ARG_WITH(libv4lconvertsubdir, AS_HELP_STRING(--with-libv4lconvertsubdir=DIR,set libv4lconvert library subdir [default=libv4l]),
    libv4lconvertsubdir=$withval, libv4lconvertsubdir="libv4l")
 
+AC_ARG_WITH(libv4l2rdssubdir, AS_HELP_STRING(--with-libv4l2rdssubdir=DIR,set libv4l2rds library subdir [default=libv4l]),
+   libv4l2rdssubdir=$withval, libv4l2rdssubdir="libv4l")
+
 AC_ARG_WITH(udevdir, AS_HELP_STRING(--with-udevdir=DIR,set udev directory [default=/lib/udev]),
    udevdir=$withval, udevdir="/lib/udev")
-
+   
 libv4l1privdir="$libdir/$libv4l1subdir"
 libv4l2privdir="$libdir/$libv4l2subdir"
 libv4l2plugindir="$libv4l2privdir/plugins"
 libv4lconvertprivdir="$libdir/$libv4lconvertsubdir"
+libv4l2rdsprivdir="$libdir/$libv4l2rdssubdir"
 
 keytablesystemdir="$udevdir/rc_keymaps"
 keytableuserdir="$sysconfdir/rc_keymaps"
@@ -166,6 +172,7 @@ AC_SUBST(libv4lconvertprivdir)
 AC_SUBST(keytablesystemdir)
 AC_SUBST(keytableuserdir)
 AC_SUBST(udevrulesdir)
+AC_SUBST(libv4l2rdsprivdir)
 AC_SUBST(pkgconfigdir)
 
 AC_DEFINE_UNQUOTED([V4L_UTILS_VERSION], ["$PACKAGE_VERSION"], [v4l-utils version string])
@@ -173,6 +180,7 @@ AC_DEFINE_DIR([LIBV4L1_PRIV_DIR], [libv4l1privdir], [libv4l1 private lib directo
 AC_DEFINE_DIR([LIBV4L2_PRIV_DIR], [libv4l2privdir], [libv4l2 private lib directory])
 AC_DEFINE_DIR([LIBV4L2_PLUGIN_DIR], [libv4l2plugindir], [libv4l2 plugin directory])
 AC_DEFINE_DIR([LIBV4LCONVERT_PRIV_DIR], [libv4lconvertprivdir], [libv4lconvert private lib directory])
+AC_DEFINE_DIR([LIBV4L2RDS_PRIV_DIR], [libv4l2rdsprivdir], [libv4l2rds private lib directory])
 AC_DEFINE_DIR([IR_KEYTABLE_SYSTEM_DIR], [keytablesystemdir], [ir-keytable preinstalled tables directory])
 AC_DEFINE_DIR([IR_KEYTABLE_USER_DIR], [keytableuserdir], [ir-keytable user defined tables directory])
 
diff --git a/lib/libv4l2rds/Makefile.am b/lib/libv4l2rds/Makefile.am
new file mode 100644
index 0000000..5796890
--- /dev/null
+++ b/lib/libv4l2rds/Makefile.am
@@ -0,0 +1,11 @@
+if WITH_LIBV4L
+lib_LTLIBRARIES = libv4l2rds.la
+include_HEADERS = ../include/libv4l2rds.h
+pkgconfig_DATA = libv4l2rds.pc
+else
+noinst_LTLIBRARIES = libv4l2rds.la
+endif
+
+libv4l2rds_la_SOURCES = libv4l2rds.c
+libv4l2rds_la_CPPFLAGS = -fvisibility=hidden $(ENFORCE_LIBV4L_STATIC) -std=c99
+libv4l2rds_la_LDFLAGS = -version-info 0 -lpthread $(DLOPEN_LIBS) $(ENFORCE_LIBV4L_STATIC)
diff --git a/lib/libv4l2rds/libv4l2rds.c b/lib/libv4l2rds/libv4l2rds.c
new file mode 100644
index 0000000..0bacaa2
--- /dev/null
+++ b/lib/libv4l2rds/libv4l2rds.c
@@ -0,0 +1,871 @@
+/*
+ * 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
+ */
+
+#include <linux/videodev2.h>
+
+#include "../include/libv4l2rds.h"
+
+/* struct to encapsulate the private state information of the decoding process */
+struct rds_private_state {
+	/* v4l2_rds has to be in first position, to allow typecasting between
+	 * v4l2_rds and rds_private_state pointers */
+	struct v4l2_rds handle;
+
+	uint8_t decode_state;
+	uint16_t new_pi;
+	uint8_t new_ps[8];
+	uint8_t new_ps_valid[8];
+	uint8_t new_pty;
+	uint8_t new_ptyn[2][4];
+	bool new_ptyn_valid[2];
+	uint8_t new_rt[64];
+	uint8_t new_rt_pos;
+	uint8_t new_ecc;
+	uint8_t new_lc;
+	uint8_t new_di;
+	uint8_t new_di_pos;
+	struct v4l2_rds_group rds_group;
+	struct v4l2_rds_data rds_data_raw[4];
+};
+
+/* states of the RDS block into group decoding state machine */
+enum rds_state {
+	RDS_EMPTY,
+	RDS_A_RECEIVED,
+	RDS_B_RECEIVED,
+	RDS_C_RECEIVED,
+};
+
+static inline uint8_t set_bit(uint8_t input, uint8_t bitmask, bool bitvalue)
+{
+	return bitvalue ? input | bitmask : input & ~bitmask;
+}
+
+/* rds_decode_a-d(..): group of functions to decode different RDS blocks
+ * into the RDS group that's currently being received
+ *
+ * block A of RDS group always contains PI code of program */
+static uint32_t rds_decode_a(struct rds_private_state *priv_state, struct v4l2_rds_data *rds_data)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	uint32_t updated_fields = 0x00;
+	uint16_t pi = (rds_data->msb << 8) | rds_data->lsb;
+
+	/* data in RDS group is uninterpreted */
+	priv_state->rds_group.pi = pi;
+
+	/* compare PI values to detect PI update (Channel Switch)
+	 * --> new PI is only accepted, if the same PI is received
+	 * at least 2 times in a row */
+	if (pi != handle->pi && pi == priv_state->new_pi) {
+		handle->pi = pi;
+		handle->valid_fields |= V4L2_RDS_PI;
+		updated_fields |= V4L2_RDS_PI;
+	} else if (pi != handle->pi && pi != priv_state->new_pi) {
+		priv_state->new_pi = pi;
+	}
+
+	return updated_fields;
+}
+
+/* block B of RDS group always contains Group Type Code, Group Type information
+ * Traffic Program Code and Program Type Code as well as 5 bits of Group Type
+ * depending information */
+static uint32_t rds_decode_b(struct rds_private_state *priv_state, struct v4l2_rds_data *rds_data)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+	uint32_t updated_fields = 0x00;
+
+	/* bits 12-15 (4-7 of msb) contain the Group Type Code */
+	grp->group_id = rds_data->msb >> 4 ;
+
+	/* bit 11 (3 of msb) defines Group Type info: 0 = A, 1 = B */
+	grp->group_version = (rds_data->msb & 0x08) ? 'B' : 'A';
+
+	/* bit 10 (2 of msb) defines Traffic program Code */
+	grp->traffic_prog = rds_data->msb & 0x04;
+	if (handle->tp != grp->traffic_prog) {
+		handle->tp = grp->traffic_prog;
+		updated_fields |= V4L2_RDS_TP;
+	}
+	handle->valid_fields |= V4L2_RDS_TP;
+
+	/* bits 0-4 contains Group Type depending information */
+	grp->data_b_lsb = (rds_data->lsb & 0x1f);
+
+	/* bits 5-9 contain the PTY code */
+	grp->pty = (rds_data->msb << 3) | (rds_data->lsb >> 5);
+	grp->pty &= 0x1f; /* mask out 3 irrelevant bits */
+	/* only accept new PTY if same PTY is received twice in a row
+	 * and filter out cases where the PTY is already known */
+	if (handle->pty == grp->pty) {
+		priv_state->new_pty = grp->pty;
+		return updated_fields;
+	}
+
+	if (priv_state->new_pty == grp->pty) {
+		handle->pty = priv_state->new_pty;
+		updated_fields |= V4L2_RDS_PTY;
+		handle->valid_fields |= V4L2_RDS_PTY;
+	} else {
+		priv_state->new_pty = grp->pty;
+	}
+
+	return updated_fields;
+}
+
+/* block C of RDS group contains either data or the PI code, depending
+ * on the Group Type - store the raw data for later decoding */
+static void rds_decode_c(struct rds_private_state *priv_state, struct v4l2_rds_data *rds_data)
+{
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+
+	grp->data_c_msb = rds_data->msb;
+	grp->data_c_lsb = rds_data->lsb;
+	/* we could decode the PI code here, because we already know if the
+	 * group is of type A or B, but it doesn't give any advantage because
+	 * we only get here after the PI code has been decoded in the first
+	 * state of the state machine */
+}
+
+/* block D of RDS group contains data - store the raw data for later decoding */
+static void rds_decode_d(struct rds_private_state *priv_state, struct v4l2_rds_data *rds_data)
+{
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+
+	grp->data_d_msb = rds_data->msb;
+	grp->data_d_lsb = rds_data->lsb;
+}
+
+static bool rds_add_oda(struct rds_private_state *priv_state, struct v4l2_rds_oda oda)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+
+	/* check if there was already an ODA announced for this group type */
+	for (int i = 0; i < handle->rds_oda.size; i++) {
+		if (handle->rds_oda.oda[i].group_id == oda.group_id)
+			/* update the AID for this ODA */
+			handle->rds_oda.oda[i].aid = oda.aid;
+			return false;
+	}
+	/* add the new ODA */
+	if (handle->rds_oda.size >= MAX_ODA_CNT)
+		return false;
+	handle->rds_oda.oda[handle->rds_oda.size++] = oda;
+	return true;
+}
+
+/* add a new AF to the list, if it doesn't exist yet */
+static bool rds_add_af_to_list(struct v4l2_rds_af_set *af_set, uint8_t af, bool is_vhf)
+{
+	uint32_t freq = 0;
+
+	/* AF0 -> "Not to be used" */
+	if (af == 0)
+		return false;
+
+	/* calculate the AF values in HZ */
+	if (is_vhf)
+		freq = 87500000 + af * 100000;
+	else if (freq <= 15)
+		freq = 152000 + af * 9000;
+	else
+		freq = 531000 + af * 9000;
+
+	/* prevent buffer overflows */
+	if (af_set->size >= MAX_AF_CNT || af_set->size >= af_set->announced_af)
+		return false;
+	/* check if AF already exists */
+	for (int i = 0; i < af_set->size; i++) {
+		if (af_set->af[i] == freq)
+			return false;
+	}
+	/* it's a new AF, add it to the list */
+	af_set->af[(af_set->size)++] = freq;
+	return true;
+}
+
+static bool rds_add_af(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+
+	/* AFs are submitted in Block 3 of type 0A groups */
+	uint8_t c_msb = priv_state->rds_group.data_c_msb;
+	uint8_t c_lsb = priv_state->rds_group.data_c_lsb;
+	bool updated_af = false;
+	struct v4l2_rds_af_set *af_set = &handle->rds_af;
+
+	/* LF / MF frequency follows */
+	if (c_msb == 250) {
+		updated_af = (rds_add_af_to_list(af_set, c_lsb, false)) ?
+			true : updated_af;
+		c_lsb = 0; /* invalidate */
+	}
+	/* announcement of AF count */
+	if (c_msb >= 225 && c_msb <= 249)
+		af_set->announced_af = c_msb - 224;
+	/* check if the data represents an AF */
+	if (c_msb < 205)
+		updated_af = (rds_add_af_to_list(af_set, c_msb, true)) ?
+			true : updated_af;
+	if (c_lsb < 205)
+		updated_af = (rds_add_af_to_list(af_set, c_lsb, true)) ?
+			true : updated_af;
+	/* did we receive all announced AFs?*/
+	if (af_set->size >= af_set->announced_af && af_set->announced_af != 0)
+		handle->valid_fields |= V4L2_RDS_AF;
+	return updated_af;
+}
+
+/* adds one char of the ps name to temporal storage, the value is validated
+ * if it is received twice in a row
+ * @pos:	position of the char within the PS name (0..7)
+ * @ps_char:	the new character to be added
+ * @return:	true, if all 8 temporal ps chars have been validated */
+static bool rds_add_ps(struct rds_private_state *priv_state, uint8_t pos, uint8_t ps_char)
+{
+	if (ps_char == priv_state->new_ps[pos]) {
+		priv_state->new_ps_valid[pos] = 1;
+	} else {
+		priv_state->new_ps[pos] = ps_char;
+		memset(priv_state->new_ps_valid, 0, 8);
+	}
+
+	/* check if all ps positions have been validated */
+	for (int i = 0; i < 8; i++)
+		if (priv_state->new_ps_valid[i] != 1)
+			return false;
+	return true;
+}
+
+/* group of functions to decode successfully received RDS groups into
+ * easily accessible data fields
+ *
+ * group 0: basic tuning and switching */
+static uint32_t rds_decode_group0(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+	bool new_ps = false;
+	bool tmp;
+	uint32_t updated_fields = 0x00;
+
+	/* bit 4 of block B contains the TA flag */
+	tmp = grp->data_b_lsb & 0x10;
+	if (handle->ta != tmp) {
+		handle->ta = tmp;
+		updated_fields |= V4L2_RDS_TA;
+	}
+	handle->valid_fields |= V4L2_RDS_TA;
+
+	/* bit 3 of block B contains the Music/Speech flag */
+	tmp = grp->data_b_lsb & 0x08;
+	if (handle->ms != tmp) {
+		handle->ms = tmp;
+		updated_fields |= V4L2_RDS_MS;
+	}
+	handle->valid_fields |= V4L2_RDS_MS;
+
+	/* bit 0-1 of block b contain program service name and decoder
+	 * control segment address */
+	uint8_t segment = (grp->data_b_lsb & 0x03);
+
+	/* put the received station-name characters into the correct position
+	 * of the station name, and check if the new PS is validated */
+	rds_add_ps(priv_state, segment * 2, grp->data_d_msb);
+	new_ps = rds_add_ps(priv_state, segment * 2 + 1, grp->data_d_lsb);
+	if (new_ps) {
+		/* check if new PS is the same as the old one */
+		if (memcmp(priv_state->new_ps, handle->ps, 8) != 0) {
+			memcpy(handle->ps, priv_state->new_ps, 8);
+			updated_fields |= V4L2_RDS_PS;
+		}
+		handle->valid_fields |= V4L2_RDS_PS;
+	}
+
+	/* bit 2 of block B contains 1 bit of the Decoder Control Information (DI)
+	 * the segment number defines the bit position
+	 * New bits are only accepted the segments arrive in the correct order */
+	bool bit2 = grp->data_b_lsb & 0x04;
+	if (segment == 0 || segment == priv_state->new_di_pos + 1) {
+		switch (segment) {
+		case 0:
+			priv_state->new_di = set_bit(priv_state->new_di,
+				V4L2_RDS_FLAG_STEREO, bit2);
+			break;
+		case 1:
+			priv_state->new_di = set_bit(priv_state->new_di,
+				V4L2_RDS_FLAG_ARTIFICIAL_HEAD, bit2);
+			priv_state->new_di_pos = segment;
+			break;
+		case 2:
+			priv_state->new_di = set_bit(priv_state->new_di,
+				V4L2_RDS_FLAG_COMPRESSED, bit2);
+			priv_state->new_di_pos = segment;
+			break;
+		case 3:
+			priv_state->new_di = set_bit(priv_state->new_di,
+				V4L2_RDS_FLAG_STATIC_PTY, bit2);
+			if (handle->di != priv_state->new_di)
+				updated_fields |= V4L2_RDS_DI;
+			handle->di = priv_state->new_di;
+			handle->valid_fields |= V4L2_RDS_DI;
+			break;
+		}
+	} else {
+		/* wrong order of DI segments -> restart */
+		priv_state->new_di_pos = 0;
+		priv_state->new_di = 0x00;
+	}
+
+	/* version A groups contain AFs in block C */
+	if (grp->group_version == 'A')
+		if (rds_add_af(priv_state))
+			updated_fields |= V4L2_RDS_AF;
+
+	return updated_fields;
+}
+
+/* group 1: slow labeling codes & program item number */
+static uint32_t rds_decode_group1(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+	uint32_t updated_fields = 0x00;
+	uint8_t variant_code = 0x00;
+
+	/* version A groups contain slow labeling codes,
+	 * version B groups only contain program item number which is a
+	 * very uncommonly used feature */
+	if (grp->group_version != 'A')
+		return 0x00;
+
+	/* bit 14-12 of block c contain the variant code */
+	variant_code = (grp->data_c_msb >> 4) & 0x07;
+	if (variant_code == 0x00) {
+		/* var 0x00 -> ECC, only accept if same lc is
+		 * received twice */
+		if (grp->data_c_lsb == priv_state->new_ecc) {
+			handle->valid_fields |= V4L2_RDS_ECC;
+			if (handle->ecc != grp->data_c_lsb)
+				updated_fields |= V4L2_RDS_ECC;
+			handle->ecc = grp->data_c_lsb;
+		} else {
+			priv_state->new_ecc = grp->data_c_lsb;
+		}
+	} else if (variant_code == 0x03) {
+		/* var 0x03 -> Language Code, only accept if same lc is
+		 * received twice */
+		if (grp->data_c_lsb == priv_state->new_lc) {
+			handle->valid_fields |= V4L2_RDS_LC;
+			updated_fields |= V4L2_RDS_LC;
+			handle->lc = grp->data_c_lsb;
+		} else {
+			priv_state->new_lc = grp->data_c_lsb;
+		}
+	}
+	return updated_fields;
+}
+
+/* group 2: radio text */
+static uint32_t rds_decode_group2(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+	uint32_t updated_fields = 0x00;
+
+	/* bit 0-3 of block B contain the segment code */
+	uint8_t segment = grp->data_b_lsb & 0x0f;
+	/* bit 4 of block b contains the A/B text flag (new radio text
+	 * will be transmitted) */
+	bool rt_ab_flag_n = grp->data_b_lsb & 0x10;
+
+	/* new Radio Text will be transmitted */
+	if (rt_ab_flag_n != handle->rt_ab_flag) {
+		handle->rt_ab_flag = rt_ab_flag_n;
+		memset(handle->rt, 0x00, 64);
+		handle->valid_fields &= ~V4L2_RDS_RT;
+		updated_fields |= V4L2_RDS_RT;
+	}
+
+	/* further decoding of data depends on type of message (A or B)
+	 * Type A allows RTs with a max length of 64 chars
+	 * Type B allows RTs with a max length of 32 chars */
+	if (grp->group_version == 'A') {
+		if (segment == 0 || segment == priv_state->new_rt_pos + 1) {
+			priv_state->new_rt[segment * 4] = grp->data_c_msb;
+			priv_state->new_rt[segment * 4 + 1] = grp->data_c_lsb;
+			priv_state->new_rt[segment * 4 + 2] = grp->data_d_msb;
+			priv_state->new_rt[segment * 4 + 3] = grp->data_d_lsb;
+			priv_state->new_rt_pos = segment;
+			if (segment == 0x0f) {
+				handle->rt_length = 64;
+				handle->valid_fields |= V4L2_RDS_RT;
+				if (memcmp(handle->rt, priv_state->new_rt, 64)) {
+					memcpy(handle->rt, priv_state->new_rt, 64);
+					updated_fields |= V4L2_RDS_RT;
+				}
+			}
+		}
+	} else {
+		if (segment == 0 || segment == priv_state->new_rt_pos + 1) {
+			priv_state->new_rt[segment * 2] = grp->data_d_msb;
+			priv_state->new_rt[segment * 2 + 1] = grp->data_d_lsb;
+			/* PI code in block C will be ignored */
+			priv_state->new_rt_pos = segment;
+			if (segment == 0x0f) {
+				handle->rt_length = 32;
+				handle->valid_fields |= V4L2_RDS_RT;
+				updated_fields |= V4L2_RDS_RT;
+				if (memcmp(handle->rt, priv_state->new_rt, 32)) {
+					memcpy(handle->rt, priv_state->new_rt, 32);
+					updated_fields |= V4L2_RDS_RT;
+				}
+			}
+		}
+	}
+
+	/* determine if complete rt was received
+	 * a carriage return (0x0d) can end a message early */
+	for (int i = 0; i < 64; i++) {
+		if (priv_state->new_rt[i] == 0x0d) {
+			handle->rt_length = i + 1;
+			handle->valid_fields |= V4L2_RDS_RT;
+			if (memcmp(handle->rt, priv_state->new_rt, handle->rt_length)) {
+					memcpy(handle->rt, priv_state->new_rt,
+						handle->rt_length);
+					updated_fields |= V4L2_RDS_RT;
+				}
+		}
+	}
+	return updated_fields;
+}
+
+/* group 3: Open Data Announcements */
+static uint32_t rds_decode_group3(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+	struct v4l2_rds_oda new_oda;
+	uint32_t updated_fields = 0x00;
+
+	if (grp->group_version != 'A')
+		return 0x00;
+
+	/* 0th bit of block b contains Group Type Info version of announced ODA
+	 * Group Type info: 0 = A, 1 = B */
+	new_oda.group_version = (grp->data_b_lsb & 0x01) ? 'B' : 'A';
+	/* 1st to 4th bit contain Group ID of announced ODA */
+	new_oda.group_id = (grp->data_b_lsb & 0x1e) >> 1;
+	/* block D contains the 16bit Application Identification Code */
+	new_oda.aid = (grp->data_d_msb << 8) | grp->data_d_lsb;
+
+	/* try to add the new ODA to the set of defined ODAs */
+	if (rds_add_oda(priv_state, new_oda)) {
+		handle->decode_information |= V4L2_RDS_ODA;
+		updated_fields |= V4L2_RDS_ODA;
+	}
+	return updated_fields;
+}
+
+/* group 4: Date and Time */
+static uint32_t rds_decode_group4(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+	uint32_t julian_date;
+	uint8_t utc_hour;
+	uint8_t utc_minute;
+	uint8_t utc_offset;
+	uint32_t updated_fields = 0x00;
+
+	if (grp->group_version != 'A')
+		return 0x00;
+
+	/* bits 0-1 of block b lsb contain bits 15 and 16 of Julian date
+	 * bits 0-7 of block c msb contain bits 7 to 14 of Julian date
+	 * bits 1-7 of block c lsb contain bits 0 to 6 of Julian date */
+	julian_date = ((grp->data_b_lsb & 0x03) << 15) |
+				(grp->data_c_msb << 7) | (grp->data_c_lsb >> 1);
+	if (handle->julian_date != julian_date) {
+		handle->julian_date = julian_date;
+		updated_fields |= V4L2_RDS_TIME;
+	}
+
+	/* bit 0 of block c lsb contains bit 4 of utc_hour
+	 * bits 4-7 of block d contains bits 0 to 3 of utc_hour */
+	utc_hour = ((grp->data_c_lsb & 0x01) << 4) | (grp->data_d_msb >> 4);
+	if (handle->utc_hour != utc_hour) {
+		handle->utc_hour = utc_hour;
+		updated_fields |= V4L2_RDS_TIME;
+	}
+
+	/* bits 0-3 of block d msb contain bits 2 to 5 of utc_minute
+	 * bits 6-7 of block d lsb contain bits 0 and 1 utc_minute */
+	utc_minute = ((grp->data_d_msb & 0x0f) << 2) | (grp->data_d_lsb >> 6);
+	if (handle->utc_minute != utc_minute) {
+		handle->utc_minute = utc_minute;
+		updated_fields |= V4L2_RDS_TIME;
+	}
+
+	/* bits 0-5 of block d lsb contain bits 0 to 5 of local time offset */
+	utc_offset = grp->data_d_lsb & 0x3f;
+	if (handle->utc_offset != utc_offset) {
+		handle->utc_offset = utc_offset;
+		updated_fields |= V4L2_RDS_TIME;
+	}
+
+	handle->valid_fields |= V4L2_RDS_TIME;
+	return updated_fields;
+}
+
+/* group 10: Program Type Name */
+static uint32_t rds_decode_group10(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	struct v4l2_rds_group *grp = &priv_state->rds_group;
+	uint32_t updated_fields = 0x00;
+	uint8_t ptyn_tmp[4];
+
+	/* bit 0 of block B contain the segment code */
+	uint8_t segment_code = grp->data_b_lsb & 0x01;
+	/* bit 4 of block b contains the A/B text flag (new ptyn
+	 * will be transmitted) */
+	bool ptyn_ab_flag_n = grp->data_b_lsb & 0x10;
+
+	if (grp->group_version != 'A')
+		return 0x00;
+
+	/* new Program Type Text will be transmitted */
+	if (ptyn_ab_flag_n != handle->ptyn_ab_flag) {
+		handle->ptyn_ab_flag = ptyn_ab_flag_n;
+		memset(handle->ptyn, 0, 8 * sizeof(char));
+		memset(priv_state->new_ptyn, 0, 8 * sizeof(char));
+		memset(priv_state->new_ptyn_valid, 0, 2 * sizeof(bool));
+		handle->valid_fields &= ~V4L2_RDS_PTYN;
+		updated_fields |= V4L2_RDS_PTYN;
+	}
+	/* copy chars to designated position within temp text field */
+	ptyn_tmp[0] = grp->data_c_msb;
+	ptyn_tmp[1] = grp->data_c_lsb;
+	ptyn_tmp[2] = grp->data_d_msb;
+	ptyn_tmp[3] = grp->data_d_lsb;
+
+	/* only validate ptyn segment if the same data is received twice */
+	if (memcmp(ptyn_tmp, priv_state->new_ptyn[segment_code], 4) == 0) {
+		priv_state->new_ptyn_valid[segment_code] = true;
+	} else {
+		for (int i = 0; i < 4; i++)
+			priv_state->new_ptyn[segment_code][i] = ptyn_tmp[i];
+		priv_state->new_ptyn_valid[segment_code] = false;
+	}
+
+	/* if both ptyn segments have been validated, accept the new ptyn */
+	if (priv_state->new_ptyn_valid[0] && priv_state->new_ptyn_valid[1]) {
+		for (int i = 0; i < 4; i++) {
+			handle->ptyn[i] = priv_state->new_ptyn[0][i];
+			handle->ptyn[4 + i] = priv_state->new_ptyn[1][i];
+		}
+		handle->valid_fields |= V4L2_RDS_PTYN;
+		updated_fields |= V4L2_RDS_PTYN;
+	}
+	return updated_fields;
+}
+
+typedef uint32_t (*decode_group_func)(struct rds_private_state *);
+
+/* array of function pointers to contain all group specific decoding functions */
+static const decode_group_func decode_group[16] = {
+	[0] = rds_decode_group0,
+	[1] = rds_decode_group1,
+	[2] = rds_decode_group2,
+	[3] = rds_decode_group3,
+	[4] = rds_decode_group4,
+	[10] = rds_decode_group10,
+};
+
+static uint32_t rds_decode_group(struct rds_private_state *priv_state)
+{
+	struct v4l2_rds *handle = &priv_state->handle;
+	uint8_t group_id = priv_state->rds_group.group_id;
+
+	/* count the group type, and decode it if it is supported */
+	handle->rds_statistics.group_type_cnt[group_id]++;
+	if (decode_group[group_id])
+		return (*decode_group[group_id])(priv_state);
+	return 0x00;
+}
+
+struct v4l2_rds *v4l2_rds_create(bool is_rbds)
+{
+	struct rds_private_state *internal_handle =
+		calloc(1, sizeof(struct rds_private_state));
+	internal_handle->handle.version = V4L2_RDS_VERSION;
+	internal_handle->handle.is_rbds = is_rbds;
+
+	return (struct v4l2_rds *)internal_handle;
+}
+
+void v4l2_rds_destroy(struct v4l2_rds *handle)
+{
+	if (handle)
+		free(handle);
+}
+
+void v4l2_rds_reset(struct v4l2_rds *handle, bool reset_statistics)
+{
+	/* treat the private & the public part of the handle */
+	struct rds_private_state *priv_state = (struct rds_private_state *) handle;
+
+	/* store members of handle that shouldn't be affected by reset*/
+	bool is_rbds = handle->is_rbds;
+	struct v4l2_rds_statistics rds_statistics = handle->rds_statistics;
+
+	/* reset the handle */
+	memset(priv_state, 0, sizeof(*priv_state));
+	/* re-initialize members */
+	handle->is_rbds = is_rbds;
+	if (!reset_statistics)
+		handle->rds_statistics = rds_statistics;
+}
+
+/* function decodes raw RDS data blocks into complete groups. Once a full group is
+ * successfully received, the group is decoded into the fields of the RDS handle.
+ * Decoding is only done once a complete group was received. This is slower compared
+ * to decoding the group type independent information up front, but adds a barrier
+ * against corrupted data (happens regularly when reception is weak) */
+uint32_t v4l2_rds_add(struct v4l2_rds *handle, struct v4l2_rds_data *rds_data)
+{
+	struct rds_private_state *priv_state = (struct rds_private_state *) handle;
+	struct v4l2_rds_data *rds_data_raw = priv_state->rds_data_raw;
+	struct v4l2_rds_statistics *rds_stats = &handle->rds_statistics;
+	uint32_t updated_fields = 0x00;
+	uint8_t *decode_state = &(priv_state->decode_state);
+
+	/* get the block id by masking out irrelevant bits */
+	int block_id = rds_data->block & V4L2_RDS_BLOCK_MSK;
+
+	rds_stats->block_cnt++;
+	/* check for corrected / uncorrectable errors in the data */
+	if (rds_data->block & V4L2_RDS_BLOCK_ERROR) {
+		block_id = -1;
+		rds_stats->block_error_cnt++;
+	} else if (rds_data->block & V4L2_RDS_BLOCK_CORRECTED) {
+		rds_stats->block_corrected_cnt++;
+	}
+
+	switch (*decode_state) {
+	case RDS_EMPTY:
+		if (block_id == 0) {
+			*decode_state = RDS_A_RECEIVED;
+			/* begin reception of a new data group, reset raw buffer to 0 */
+			memset(rds_data_raw, 0, sizeof(rds_data_raw));
+			rds_data_raw[0] = *rds_data;
+		} else {
+			/* ignore block if it is not the first block of a group */
+			rds_stats->group_error_cnt++;
+		}
+		break;
+
+	case RDS_A_RECEIVED:
+		if (block_id == 1) {
+			*decode_state = RDS_B_RECEIVED;
+			rds_data_raw[1] = *rds_data;
+		} else {
+			/* received block with unexpected block id, reset state machine */
+			rds_stats->group_error_cnt++;
+			*decode_state = RDS_EMPTY;
+		}
+		break;
+
+	case RDS_B_RECEIVED:
+		/* handle type C and C' blocks alike */
+		if (block_id == 2 || block_id ==  4) {
+			*decode_state = RDS_C_RECEIVED;
+			rds_data_raw[2] = *rds_data;
+		} else {
+			rds_stats->group_error_cnt++;
+			*decode_state = RDS_EMPTY;
+		}
+		break;
+
+	case RDS_C_RECEIVED:
+		if (block_id == 3) {
+			*decode_state = RDS_EMPTY;
+			rds_data_raw[3] = *rds_data;
+			/* a full group was received */
+			rds_stats->group_cnt++;
+			/* decode group type independent fields */
+			memset(&priv_state->rds_group, 0, sizeof(priv_state->rds_group));
+			updated_fields |= rds_decode_a(priv_state, &rds_data_raw[0]);
+			updated_fields |= rds_decode_b(priv_state, &rds_data_raw[1]);
+			rds_decode_c(priv_state, &rds_data_raw[2]);
+			rds_decode_d(priv_state, &rds_data_raw[3]);
+			/* decode group type dependent fields */
+			updated_fields |= rds_decode_group(priv_state);
+			return updated_fields;
+		}
+		rds_stats->group_error_cnt++;
+		*decode_state = RDS_EMPTY;
+		break;
+
+	default:
+		/* every unexpected block leads to a reset of the sm */
+		rds_stats->group_error_cnt++;
+		*decode_state = RDS_EMPTY;
+	}
+	/* if we reach here, no RDS group was completed */
+	return 0x00;
+}
+
+const char *v4l2_rds_get_pty_str(const struct v4l2_rds *handle)
+{
+	const uint8_t pty = handle->pty;
+
+	if (pty >= 32)
+		return NULL;
+
+	static const char *rds_lut[32] = {
+		"None", "News", "Affairs", "Info", "Sport", "Education", "Drama",
+		"Culture", "Science", "Varied Speech", "Pop Music",
+		"Rock Music", "Easy Listening", "Light Classics M",
+		"Serious Classics", "Other Music", "Weather", "Finance",
+		"Children", "Social Affairs", "Religion", "Phone In",
+		"Travel & Touring", "Leisure & Hobby", "Jazz Music",
+		"Country Music", "National Music", "Oldies Music", "Folk Music",
+		"Documentary", "Alarm Test", "Alarm!"
+	};
+	static const char *rbds_lut[32] = {
+		"None", "News", "Information", "Sports", "Talk", "Rock",
+		"Classic Rock", "Adult Hits", "Soft Rock", "Top 40", "Country",
+		"Oldies", "Soft", "Nostalgia", "Jazz", "Classical",
+		"R&B", "Soft R&B", "Foreign Language", "Religious Music",
+		"Religious Talk", "Personality", "Public", "College",
+		"Spanish Talk", "Spanish Music", "Hip-Hop", "Unassigned",
+		"Unassigned", "Weather", "Emergency Test", "Emergency"
+	};
+
+	return handle->is_rbds ? rbds_lut[pty] : rds_lut[pty];
+}
+
+const char *v4l2_rds_get_country_str(const struct v4l2_rds *handle)
+{
+	/* defines the  region of the world
+	 * 0x0e = Europe, 0x0d = Africa, 0x0a = ITU Region 2,
+	 * 0x0f = ITU Region 3*/
+	uint8_t ecc_h = handle->ecc >> 4;
+	/* sub identifier for the region, valid range 0..4 */
+	uint8_t ecc_l = handle->ecc & 0x0f;
+	/* bits 12-15 pi contain the country code */
+	uint8_t country_code = handle->pi >> 12;
+
+	/* LUT for European countries
+	 * the standard doesn't define every possible value but leaves some
+	 * undefined. An exception is e4-7 which is defines as a dash ("-") */
+	static const char *e_lut[5][16] = {
+	{
+		NULL, "DE", "DZ", "AD", "IL", "IT", "BE", "RU", "PS", "AL",
+		"AT", "HU", "MT", "DE", NULL, "EG"
+	}, {
+		NULL, "GR", "CY", "SM", "CH", "JO", "FI", "LU", "BG", "DK",
+		"GI", "IQ", "GB", "LY", "RO", "FR"
+	}, {
+		" ", "MA", "CZ", "PL", "VA", "SK", "SY", "TN", NULL, "LI",
+		"IS", "MC", "LT", "RS", "ES", "NO"
+	}, {
+		NULL, "ME", "IE", "TR", "MK", NULL, NULL, NULL, "NL", "LV",
+		"LB", "AZ", "HR", "KZ", "SE", "BY"
+	}, {
+		NULL, "MD", "EE", "KG", NULL, NULL, "UA", "-", "PT", "SI",
+		"AM", NULL, "GE", NULL, NULL, "BA"
+	}
+	};
+
+	/* for now only European countries are supported -> ECC E0 - E4
+	 * but the standard defines country codes for the whole world,
+	 * that's the reason for returning "unknown" instead of a NULL
+	 * pointer until all defined countries are supported */
+	if (ecc_h == 0x0e && ecc_l <= 0x04)
+		return e_lut[ecc_l][country_code];
+	return "Unknown";
+}
+
+static const char *rds_language_lut(const uint8_t lc)
+{
+	const uint8_t max_lc = 127;
+	static const char *language_lut[128] = {
+		"Unknown", "Albanian", "Breton", "Catalan",
+		"Croatian", "Welsh", "Czech", "Danish",
+		"German", "English", "Spanish", "Esperanto",
+		"Estonian", "Basque", "Faroese", "French",
+		"Frisian", "Irish", "Gaelic", "Galician",
+		"Icelandic", "Italian", "Lappish", "Latin",
+		"Latvian", "Luxembourgian", "Lithuanian", "Hungarian",
+		"Maltese", "Dutch", "Norwegian", "Occitan",
+		"Polish", "Portuguese", "Romanian", "Ramansh",
+		"Serbian", "Slovak", "Slovene", "Finnish",
+		"Swedish", "Turkish", "Flemish", "Walloon",
+		" ", " ", " ", " ", " ", " ", " ", " ",
+		" ", " ", " ", " ", " ", " ", " ", " ",
+		" ", " ", " ", " ", " ", " ", " ", " ",
+		" ", "Zulu", "Vietnamese", "Uzbek",
+		"Urdu", "Ukrainian", "Thai", "Telugu",
+		"Tatar", "Tamil", "Tadzhik", "Swahili",
+		"Sranan Tongo", "Somali", "Sinhalese", "Shona",
+		"Serbo-Croat", "Ruthenian", "Russian", "Quechua",
+		"Pushtu", "Punjabi", "Persian", "Papamiento",
+		"Oriya", "Nepali", "Ndebele", "Marathi",
+		"Moldavian", "Malaysian", "Malagasay", "Macedonian",
+		"Laotian", "Korean", "Khmer", "Kazahkh",
+		"Kannada", "Japanese", "Indonesian", "Hindi",
+		"Hebrew", "Hausa", "Gurani", "Gujurati",
+		"Greek", "Georgian", "Fulani", "Dani",
+		"Churash", "Chinese", "Burmese", "Bulgarian",
+		"Bengali", "Belorussian", "Bambora", "Azerbijani",
+		"Assamese", "Armenian", "Arabic", "Amharic"
+	};
+	return (lc > max_lc) ? "Unknown" : language_lut[lc];
+}
+
+const char *v4l2_rds_get_language_str(const struct v4l2_rds *handle)
+{
+	return rds_language_lut(handle->lc);
+}
+
+const char *v4l2_rds_get_coverage_str(const struct v4l2_rds *handle)
+{
+	/* bits 8-11 contain the area coverage code */
+	uint8_t coverage = (handle->pi >> 8) & 0X0f;
+	static const char *coverage_lut[16] = {
+		"Local", "International", "National", "Supra-Regional",
+		"Regional 1", "Regional 2", "Regional 3", "Regional 4",
+		"Regional 5", "Regional 6", "Regional 7", "Regional 8",
+		"Regional 9", "Regional 10", "Regional 11", "Regional 12"
+	};
+
+	return coverage_lut[coverage];
+}
+
+const struct v4l2_rds_group *v4l2_rds_get_group
+	(const struct v4l2_rds *handle)
+{
+	struct rds_private_state *priv_state = (struct rds_private_state *) handle;
+	return &priv_state->rds_group;
+}
diff --git a/lib/libv4l2rds/libv4l2rds.pc.in b/lib/libv4l2rds/libv4l2rds.pc.in
new file mode 100644
index 0000000..cc1d5f6
--- /dev/null
+++ b/lib/libv4l2rds/libv4l2rds.pc.in
@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+includedir=@includedir@
+libdir=@libdir@
+
+Name: libv4l2rds
+Description: v4l2 RDS decode library
+Version: @PACKAGE_VERSION@
+Libs: -L${libdir} -lv4l2rds
+Libs.private: -lpthread
+Cflags: -I${includedir}
-- 
1.7.10.4

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