/*
 *  libMirage: CD-TEXT encoder/decoder
 *  Copyright (C) 2006-2014 Rok Mandeljc
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 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, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/**
 * SECTION: mirage-cdtext-coder
 * @title: MirageCdTextCoder
 * @short_description: General-purpose CD-TEXT encoder/decoder object.
 * @see_also: #MirageLanguage, #MirageSession
 * @include: mirage-cdtext-coder.h
 *
 * #MirageCdTextCoder object is a general-purpose CD-TEXT encoder/decoder.
 * It was designed to be used by #MirageSession objects to encode and decode
 * CD-TEXT data, but it could be used in other applications as well.
 *
 * It is loosely based on the CD-TEXT encoding/decoding code found in
 * cdrdao and supports 8 CD-TEXT blocks with pack types from 0x80 to
 * 0x8F. When encoding data, pack size data (pack type 0x8F) is always
 * generated.
 *
 * To be used as encoder, a #MirageCdTextCoder encoder must be first
 * initialized with mirage_cdtext_encoder_init(). Then, information for
 * at least one CD-TEXT block (up to 8 are supported) should be set with
 * mirage_cdtext_encoder_set_block_info(). After all the CD-TEXT data is
 * added to encoder with mirage_cdtext_encoder_add_data(), buffer containing
 * the encoded data can be obtained with mirage_cdtext_encoder_encode().
 *
 * To use a #MirageCdTextCoder as CD-TEXT decoder, one should first
 * initialize it with mirage_cdtext_decoder_init(). This function already
 * performs all the decoding; block information can be obtained with
 * mirage_cdtext_decoder_get_block_info() and data for each block can
 * be obtained with mirage_cdtext_decoder_get_data() and the appropriate
 * callback function.
 */

#include "mirage/config.h"
#include "mirage/mirage.h"

#include <glib/gi18n-lib.h>

#define __debug__ "CDTEXT-Coder"


/**********************************************************************\
 *                         Common definitions                         *
\**********************************************************************/
typedef struct
{
    gint block_number;
    gint pack_type;
    gint track_number;

    guint8 *data;
    gint data_len;
} CDTextDecodedPack;

typedef struct
{
    /* Header */
    guint8 pack_type;
    guint8 track_number;
    guint8 seq_number;
    guint8 block_number;
    /* Data */
    guint8 data[12];
    /* CRC */
    guint8 crc[2];
} CDTextEncodedPack;

typedef struct
{
    guint8 charset;
    guint8 first_track;
    guint8 last_track;
    guint8 copyright;
    guint8 pack_count[16];
    guint8 last_seqnum[8];
    guint8 language_codes[8];
} CDTextSizeInfo;


/**********************************************************************\
 *                          Private structure                         *
\***********************************************************************/
typedef struct
{
    gint code; /* Language code */
    gint charset; /* Character set */
    gint first_track; /* First track */
    gint last_track; /* Last track */
    gint copyright; /* Copyright flags */

    GList *packs_list; /* List of packs data */

    CDTextEncodedPack *size_info; /* Pointer to size info packs */
    gint seq_count; /* Sequence count */
    gint pack_count[16]; /* Pack types count */
} MirageCdTextCoderBlock;


struct _MirageCdTextCoderPrivate
{
    /* Buffer */
    guint8 *buffer;
    gint buflen;

    /* EncDec */
    CDTextEncodedPack *cur_pack; /* Pointer to current pack */
    gint cur_pack_fill; /* How much of current pack is used */

    /* Blocks */
    gint num_blocks; /* Number of blocks */
    MirageCdTextCoderBlock *blocks;

    gint length; /* Overall length, in packs */
};


/***********************************************************************\
 *                          Private functions                          *
\***********************************************************************/
static gint sort_pack_data (CDTextDecodedPack *pack1, CDTextDecodedPack *pack2)
{
    if (pack1->block_number < pack2->block_number) {
        return -1;
    } else if (pack1->block_number > pack2->block_number) {
        return 1;
    } else {
        if (pack1->pack_type < pack2->pack_type) {
            return -1;
        } else if (pack1->pack_type > pack2->pack_type) {
            return 1;
        } else {
            if (pack1->track_number < pack2->track_number) {
                return -1;
            } else if (pack1->track_number > pack2->track_number) {
                return 1;
            } else {
                return 0;
            }
        }
    }
}


static void mirage_cdtext_coder_cleanup (MirageCdTextCoder *self)
{
    /* Cleanup the lists */
    for (gint i = 0; i < self->priv->num_blocks; i++) {
        GList *list = self->priv->blocks[i].packs_list;
        if (!list) {
            continue;
        }

        for (GList *entry = list; entry; entry = entry->next) {
            CDTextDecodedPack *pack_data = entry->data;

            g_free(pack_data->data);
            g_free(pack_data);
        }
        g_list_free(list);
    }

    self->priv->buffer = NULL;
    self->priv->buflen = 0;

    memset(self->priv->blocks, 0, self->priv->num_blocks*sizeof(MirageCdTextCoderBlock));
}


static gint mirage_cdtext_coder_lang2block (MirageCdTextCoder *self, gint code)
{
    gint ret = 0;

    for (gint i = 0; i < 8; i++) {
        if (self->priv->blocks[i].code == code) {
            ret = i;
            break;
        }
    }

    return ret;
}

static gint mirage_cdtext_coder_block2lang (MirageCdTextCoder *self, gint block)
{
    return self->priv->blocks[block].code;
}


static void add_crc_to_pack (CDTextEncodedPack *pack)
{
    guint16 crc;
    guint16 *dest = (guint16 *) &pack->crc;

    crc = mirage_helper_calculate_crc16((guint8 *) pack, 16, crc16_1021_lut, FALSE, TRUE);

    *dest = GUINT16_TO_BE(crc);
}


static void mirage_cdtext_encoder_initialize_pack (MirageCdTextCoder *self, gint block, gint type, gint track, gint carry_len)
{
    if (!self->priv->cur_pack->pack_type) {
        /*g_debug("%s: Empty pack, initializing\n", __debug__);*/
        self->priv->cur_pack->pack_type = type;
        if (type != MIRAGE_LANGUAGE_PACK_SIZE) {
            self->priv->cur_pack->track_number = track;
            self->priv->cur_pack->seq_number = self->priv->blocks[block].seq_count;
            self->priv->cur_pack->block_number |= (block) << 4;
            self->priv->cur_pack->block_number |= (carry_len < 15) ? carry_len : 15;
        } else {
            /* Special handling for 0x8F packs */
            self->priv->cur_pack->track_number = self->priv->blocks[block].pack_count[type-0x80];
            self->priv->cur_pack->seq_number = self->priv->blocks[block].seq_count;
            self->priv->cur_pack->block_number |= (block) << 4;
            /* Set up pointer to first pack of size info */
            if (!self->priv->blocks[block].size_info) {
                self->priv->blocks[block].size_info = self->priv->cur_pack;
            }
        }

        self->priv->blocks[block].seq_count++;
        self->priv->blocks[block].pack_count[type-0x80]++;
        self->priv->length++;
    } else {
        /*g_debug("%s: Pack already initialized (0x%X)\n", __debug__, encoder->cur_pack->pack_type);*/
    }
}

static void mirage_cdtext_encoder_encode_pack (MirageCdTextCoder *self, CDTextDecodedPack *pack) {
    /* If current pack is already initialized and the data we're trying to pack
       is if different type, open new pack; this way, we don't have to check if
       the language has changed (if it has, so has the pack type... from 0x8F
       to 0x8X */
    if (self->priv->cur_pack->pack_type && (pack->pack_type != self->priv->cur_pack->pack_type)) {
        /*g_debug("%s: Different pack type, open new pack!\n", __debug__);*/
        self->priv->cur_pack++;
        self->priv->cur_pack_fill = 0;
    }

    gint cur_len = pack->data_len;
    guint8 *ptr = pack->data;
    gint carry_len = 0; /* How many of characters are contained in previous pack(s) */
    while (cur_len > 0) {
        gint copy_len;

        /* If the current pack is full, open a new one */
        if (self->priv->cur_pack_fill == 12) {
            /*g_debug("%s: Current pack full, moving to next!\n", __debug__);*/
            /* Open new pack */
            self->priv->cur_pack++;
            self->priv->cur_pack_fill = 0;
        }

        mirage_cdtext_encoder_initialize_pack(self, pack->block_number, pack->pack_type, pack->track_number, carry_len);

        copy_len = MIN(12 - self->priv->cur_pack_fill, cur_len);
        /*g_debug("%s: Copying %i bytes (cur_len = %i, cur_fill = %i)\n", __debug__, copy_len, cur_len, encoder->cur_pack_fill);*/

        memcpy(self->priv->cur_pack->data+self->priv->cur_pack_fill, ptr, copy_len);

        /* Set the current fill */
        self->priv->cur_pack_fill += copy_len;

        cur_len -= copy_len;
        ptr += copy_len;
        carry_len += copy_len;
    }
}

static void mirage_cdtext_encoder_generate_size_info (MirageCdTextCoder *self, gint block, guint8 **data, gint *len)
{
    CDTextSizeInfo *size_info = g_new0(CDTextSizeInfo, 1);

    size_info->charset = self->priv->blocks[block].charset; /* Character set */
    size_info->first_track = self->priv->blocks[block].first_track; /* First track */
    size_info->last_track = self->priv->blocks[block].last_track; /* Last track */
    size_info->copyright = self->priv->blocks[block].copyright; /* Copyright */

    /* Pack count */
    for (gint i = 0; i < 16; i++) {
        size_info->pack_count[i] = self->priv->blocks[block].pack_count[i];
    }

    /* Last sequence numbers and language codes */
    for (gint i = 0; i < 8; i++) {
        /* Set only if we have at least one pack for that language */
        if (self->priv->blocks[i].seq_count > 0) {
            size_info->last_seqnum[i] = self->priv->blocks[i].seq_count-1; /* It overshoots by one */
            size_info->language_codes[i] = self->priv->blocks[i].code;
        }
    }

    *data = (guint8 *)size_info;
    *len = sizeof(CDTextSizeInfo);
}

static void mirage_cdtext_decoder_read_size_info (MirageCdTextCoder *self G_GNUC_UNUSED, CDTextEncodedPack *size_info_pack, CDTextSizeInfo **data)
{
    guint8 *size_info = g_malloc0(sizeof(CDTextSizeInfo));
    CDTextEncodedPack *cur_pack = size_info_pack;

    for (gint i = 0; i < sizeof(CDTextSizeInfo)/12; i++) {
        memcpy(size_info+12*i, cur_pack->data, 12);
        cur_pack++;
    }

    *data = (CDTextSizeInfo *)size_info;
}


/**********************************************************************\
 *                         Public API: Encoder                        *
\**********************************************************************/
/**
 * mirage_cdtext_encoder_init:
 * @self: a #MirageCdTextCoder
 * @buffer: (in) (array length=buflen): buffer into which data will be encoded
 * @buflen: (in): buffer length
 *
 * Initializes CD-TEXT encoder.
 */
void mirage_cdtext_encoder_init (MirageCdTextCoder *self, guint8 *buffer, gint buflen)
{
    /* Cleanup old data */
    mirage_cdtext_coder_cleanup(self);

    /* Set new buffer */
    self->priv->buffer = buffer;
    self->priv->buflen = buflen;

    self->priv->cur_pack = (CDTextEncodedPack *)self->priv->buffer;
}

/**
 * mirage_cdtext_encoder_set_block_info:
 * @self: a #MirageCdTextCoder
 * @block: (in): block number
 * @code: (in): language code
 * @charset: (in): character set
 * @copyright: (in): copyright flag
 * @error: (out) (allow-none): location to store error, or %NULL
 *
 * Sets block information for CD-TEXT block specified by @block. @block must be
 * a valid block number (0-7). @code is the language code that is to be assigned
 * to the block (e.g. 9 for English), @charset denotes character set that is used within
 * the block, and @copyright is the copyright flag for the block.
 *
 * Returns: %TRUE on success, %FALSE on failure
 */
gboolean mirage_cdtext_encoder_set_block_info (MirageCdTextCoder *self, gint block, gint code, gint charset, gint copyright, GError **error)
{
    /* Verify that block is valid */
    if (block > self->priv->num_blocks) {
        MIRAGE_DEBUG(self, MIRAGE_DEBUG_CDTEXT, "%s: invalid block (%i)!\n", __debug__, block);
        g_set_error(error, MIRAGE_ERROR, MIRAGE_ERROR_LANGUAGE_ERROR, Q_("Invalid block number #%i!"), block);
        return FALSE;
    }

    MIRAGE_DEBUG(self, MIRAGE_DEBUG_CDTEXT, "%s: initialized block %i; code: %i; charset: %i; copyright: %i\n", __debug__, block, code, charset, copyright);
    self->priv->blocks[block].code = code;
    self->priv->blocks[block].charset = charset;
    self->priv->blocks[block].copyright = copyright;

    return TRUE;
}

/**
 * mirage_cdtext_encoder_add_data:
 * @self: a #MirageCdTextCoder
 * @code: (in): language code
 * @type: (in): data type
 * @track: (in): track number
 * @data: (in) (array length=data_len): data
 * @data_len: (in): data length
 *
 * Adds data to the encoder. @code is language code of the block the data
 * should be added to. @type denotes pack type and should be one of #MirageLanguagePackType.
 * @track is track number the data belongs to, or 0 if data is global (belongs to disc/session).
 * @data is buffer containing data to be added, and @data_len is length of data in the buffer.
 *
 * This function does not perform any encoding yet; it merely adds the data into
 * encoder's internal representation of CD-TEXT block.
 *
 * <note>
 * Block needs to have its information set with mirage_cdtext_encoder_set_block_info()
 * before data can be added to it.
 * </note>
 */
void mirage_cdtext_encoder_add_data (MirageCdTextCoder *self, gint code, gint type, gint track, const guint8 *data, gint data_len)
{
    CDTextDecodedPack *pack_data;
    gint block = mirage_cdtext_coder_lang2block(self, code); /* Language code -> block conversion */

    /* Create pack structure */
    pack_data = g_new0(CDTextDecodedPack, 1);
    pack_data->block_number = block;
    pack_data->pack_type = type;
    pack_data->track_number = track;
#if GLIB_CHECK_VERSION(2, 68, 0)
    pack_data->data = g_memdup2(data, data_len);
#else
    pack_data->data = g_memdup(data, data_len);
#endif
    pack_data->data_len = data_len;

    /* Add internal representation to ordered list... */
    self->priv->blocks[block].packs_list = g_list_insert_sorted(self->priv->blocks[block].packs_list, pack_data, (GCompareFunc)sort_pack_data);

    /* Set the number of first track that has language... this is not
       very reliable, but I do believe all tracks from now on are
       required by specs to have language block? */
    if (!self->priv->blocks[block].first_track) {
        self->priv->blocks[block].first_track = track;
    }
    /* Keep setting the last track... */
    self->priv->blocks[block].last_track = track;
}

/**
 * mirage_cdtext_encoder_encode:
 * @self: a #MirageCdTextCoder
 * @buffer: (out) (array length=buflen): location to store buffer
 * @buflen: (out): location to store buffer length
 *
 * Encodes the CD-TEXT data. Pointer to buffer containing the encoded data is
 * stored in @buffer, and length of data in buffer is stored in @buflen.
 *
 * Note that @buffer is the same as the argument passed to mirage_cdtext_encoder_init().
 */
void mirage_cdtext_encoder_encode (MirageCdTextCoder *self, guint8 **buffer, gint *buflen)
{
    MIRAGE_DEBUG(self, MIRAGE_DEBUG_CDTEXT, "%s: encoding CD-TEXT...\n", __debug__);

    /* Encode all blocks */
    for (gint i = 0; i < self->priv->num_blocks; i++) {
        /* Block is valid only if it has language code set */
        if (self->priv->blocks[i].code) {
            MIRAGE_DEBUG(self, MIRAGE_DEBUG_CDTEXT, "%s: encoding block %i; code %i\n", __debug__, i, self->priv->blocks[i].code);

            /* Encode all on list */
            for (GList *entry = self->priv->blocks[i].packs_list; entry; entry = entry->next) {
                mirage_cdtext_encoder_encode_pack(self, entry->data);
            }

            /* We need to 'reserve' some space for size info */
            CDTextDecodedPack pack_data;
            CDTextSizeInfo size_info;
            memset(&size_info, 0, sizeof(size_info));

            pack_data.block_number = i;
            pack_data.pack_type = 0x8F;
            pack_data.track_number = 0;
            pack_data.data = (guint8 *)&size_info;
            pack_data.data_len = sizeof(size_info);

            mirage_cdtext_encoder_encode_pack(self, &pack_data);
        } else {
            MIRAGE_DEBUG(self, MIRAGE_DEBUG_CDTEXT, "%s: block %i not valid\n", __debug__, i);
        }
    }

    /* Now that all the packs have been encoded, we can generate size info */
    for (gint i = 0; i < 8; i++) {
        /* Having pointer set means we're using this language... */
        if (self->priv->blocks[i].size_info) {
            guint8 *size_info;
            gint size_info_len;

            gint old_len;

            /* Generate size info */
            mirage_cdtext_encoder_generate_size_info(self, i, &size_info, &size_info_len);

            /* Write into previously reserved size info packs */
            self->priv->cur_pack = self->priv->blocks[i].size_info;
            self->priv->cur_pack_fill = 0;

            /* Store current length */
            old_len = self->priv->length;

            /* Encode pack */
            CDTextDecodedPack pack_data;
            pack_data.block_number = i;
            pack_data.pack_type = 0x8F;
            pack_data.track_number = 0;
            pack_data.data = size_info;
            pack_data.data_len = size_info_len;

            mirage_cdtext_encoder_encode_pack(self, &pack_data);

            /* Restore length */
            self->priv->length = old_len;

            /* Free size info */
            g_free(size_info);
        }
    }

    /* Generate CRC for all packs */
    self->priv->cur_pack = (CDTextEncodedPack *)self->priv->buffer;
    for (gint i = 0; i < self->priv->length; i++) {
        add_crc_to_pack(self->priv->cur_pack);
        self->priv->cur_pack++;
    }

    *buflen = self->priv->length*sizeof(CDTextEncodedPack);
    *buffer = self->priv->buffer;

    MIRAGE_DEBUG(self, MIRAGE_DEBUG_CDTEXT, "%s: done encoding CD-TEXT; length: 0x%X\n", __debug__, *buflen);
}


/**********************************************************************\
 *                         Public API: Decoder                        *
\**********************************************************************/
/**
 * mirage_cdtext_decoder_init:
 * @self: a #MirageCdTextCoder
 * @buffer: (in) (array length=buflen): buffer containing encoded data
 * @buflen: (in): length of data in buffer
 *
 * Initializes CD-TEXT decoder. @buffer is the buffer containing encoded CD-TEXT
 * data and @buflen is length of data in the buffer.
 *
 * This function decodes CD-TEXT data and stores it in decoder's internal representation.
 * Information about decoded CD-TEXT blocks and their data can be obtained via
 * subsequent calls to mirage_cdtext_decoder_get_block_info() and
 * mirage_cdtext_decoder_get_data().
 *
 */
void mirage_cdtext_decoder_init (MirageCdTextCoder *self, guint8 *buffer, gint buflen)
{
    /* Cleanup old data */
    mirage_cdtext_coder_cleanup(self);

    /* Set new buffer */
    self->priv->buffer = buffer;
    self->priv->buflen = buflen;
    self->priv->cur_pack = (CDTextEncodedPack *)self->priv->buffer;
    self->priv->length = buflen/sizeof(CDTextEncodedPack);

    /* Read size info packs */
    gint i = 0;
    while (i < self->priv->length) {
        CDTextEncodedPack *cur_pack = self->priv->cur_pack+i;

        if (cur_pack->pack_type == 0x8F) {
            gint block = (cur_pack->block_number & 0xF0) >> 4;
            self->priv->blocks[block].size_info = cur_pack;

            CDTextSizeInfo *size_info = NULL;
            mirage_cdtext_decoder_read_size_info(self, cur_pack, &size_info);
            self->priv->blocks[block].code = size_info->language_codes[block];
            self->priv->blocks[block].charset = size_info->charset;
            self->priv->blocks[block].copyright = size_info->copyright;
            self->priv->blocks[block].first_track = size_info->first_track;
            self->priv->blocks[block].last_track = size_info->last_track;

            self->priv->blocks[block].seq_count = size_info->last_seqnum[block] + 1;
            for (gint j = 0; j < 16; j++) {
                self->priv->blocks[block].pack_count[j] = size_info->pack_count[j];
            }
            g_free(size_info);

            i += 3;
        } else {
            i++;
        }
    }

    /* Now decode... go over all blocks and decode valid ones */
    for (gint block = 0; block < 8; block++) {
        gchar tmp_buffer[256 * 12];
        memset(tmp_buffer, 0xFF, sizeof(tmp_buffer));
        gchar *ptr = tmp_buffer;
        gint tmp_len = 0;
        gint cur_track = 0;

        /* Skip empty blocks */
        if (!self->priv->blocks[block].seq_count) {
            continue;
        }

        self->priv->cur_pack = self->priv->blocks[block].size_info - (self->priv->blocks[block].seq_count - 3);

        while (self->priv->cur_pack < self->priv->blocks[block].size_info) {
            if (self->priv->cur_pack->pack_type != (self->priv->cur_pack - 1)->pack_type) {
                /*g_debug("%s: new pack type, resetting strings...\n", __debug__);*/
                memset(tmp_buffer, 0xFF, sizeof(tmp_buffer));
                tmp_len = 0;
                ptr = tmp_buffer;
            }

            /* Current data offset */
            gchar *cur_data = (gchar *)self->priv->cur_pack->data + self->priv->cur_pack_fill;
            /* Length of transfer */
            gint copy_len = MIN(strlen(cur_data) + 1, 12 - self->priv->cur_pack_fill);

            /* Copy */
            memcpy(ptr, self->priv->cur_pack->data + self->priv->cur_pack_fill, copy_len);
            /* Do some necesssary calcs */
            self->priv->cur_pack_fill += copy_len;
            ptr += copy_len;
            tmp_len += copy_len;

            /* The way of the lazy programmer (TM)... we set whole string to 0xFF
               and then wait 'till we get terminating 0 at the end :D (we also need
               to check whether string doesn't contain just "\0", which keeps getting
               returned once we hit the padding at the end of a pack types...) */
            if (!tmp_buffer[tmp_len-1] && strlen(tmp_buffer)) {
                /* Pack the data and add it to the list; as simple as that... */
                CDTextDecodedPack *pack_data = g_new0(CDTextDecodedPack, 1);
                pack_data->block_number = block;
                pack_data->pack_type = self->priv->cur_pack->pack_type;
                pack_data->track_number = cur_track;
#if GLIB_CHECK_VERSION(2, 68, 0)
                pack_data->data = g_memdup2(tmp_buffer, tmp_len);
#else
                pack_data->data = g_memdup(tmp_buffer, tmp_len);
#endif
                pack_data->data_len = tmp_len;

                self->priv->blocks[block].packs_list = g_list_insert_sorted(self->priv->blocks[block].packs_list, pack_data, (GCompareFunc)sort_pack_data);

                /* Clear the temporary buffer */
                memset(tmp_buffer, 0xFF, sizeof(tmp_buffer));
                tmp_len = 0;
                ptr = tmp_buffer;

                /* Increase track number; this is to account for strings too short
                   to cause switch to next pack, whose track number is consequently
                   stored nowhere... */
                cur_track++;
            }

            if (self->priv->cur_pack_fill == 12) {
                /*g_debug("%s: reached the end of packet, going to the next one\n");*/
                self->priv->cur_pack_fill = 0;
                self->priv->cur_pack++;
                /* Set current track number */
                cur_track = self->priv->cur_pack->track_number;
            }
        }
    }
}

/**
 * mirage_cdtext_decoder_get_block_info:
 * @self: a #MirageCdTextCoder
 * @block: (in): block number
 * @code: (out) (allow-none): location to store language code, or %NULL
 * @charset: (out) (allow-none): location to store character set, or %NULL
 * @copyright: (out) (allow-none): location to store copyright flag, or %NULL
 * @error: (out) (allow-none): location to store error, or %NULL
 *
 * Retrieves block information for CD-TEXT block specified by @block. @block
 * must be a valid block number (0-7). Language code assigned to the block is
 * stored in @code, code of character set used within block is stored in
 * @charset and block's copyright flag is stored in @copyright.
 *
 * Returns: %TRUE on success, %FALSE on failure
 */
gboolean mirage_cdtext_decoder_get_block_info (MirageCdTextCoder *self, gint block, gint *code, gint *charset, gint *copyright, GError **error)
{
    /* Verify that block is valid */
    if (block > self->priv->num_blocks) {
        g_set_error(error, MIRAGE_ERROR, MIRAGE_ERROR_LANGUAGE_ERROR, Q_("Block number %d exceeds number of blocks %d!"), block, self->priv->num_blocks);
        return FALSE;
    }
    if (!self->priv->blocks[block].code) {
        /* FIXME: error */
        g_set_error(error, MIRAGE_ERROR, MIRAGE_ERROR_LANGUAGE_ERROR, Q_("Requested block %d has no language code set!"), block);
        return FALSE;
    }

    if (code) {
        *code = self->priv->blocks[block].code;
    }
    if (charset) {
        *charset = self->priv->blocks[block].charset;
    }
    if (copyright) {
        *copyright = self->priv->blocks[block].copyright;
    }

    return TRUE;
}

/**
 * mirage_cdtext_decoder_get_data:
 * @self: a #MirageCdTextCoder
 * @block: (in): block number
 * @callback_func: (in) (scope call): callback function
 * @user_data: (in) (closure): data to be passed to callback function
 *
 * Retrieves data for CD-TEXT block specified by @block. @block must be a valid
 * block number (0-7). It calls @callback_func for every data pack that has been
 * encoded in the block.
 *
 * If @callback_func returns %FALSE, the function immediately returns %FALSE.
 *
 * Returns: %TRUE on success, %FALSE on failure
 */
gboolean mirage_cdtext_decoder_get_data (MirageCdTextCoder *self, gint block, MirageCdTextDataCallback callback_func, gpointer user_data)
{
    /* Go over the list and call the callback for each entry */
    for(GList *entry = self->priv->blocks[block].packs_list; entry; entry = entry->next) {
        CDTextDecodedPack *pack_data = entry->data;
        gint code = mirage_cdtext_coder_block2lang(self, pack_data->block_number);

        if (!callback_func(code, pack_data->pack_type, pack_data->track_number, pack_data->data, pack_data->data_len, user_data)) {
            return FALSE;
        }
    }

    return TRUE;
}


/**********************************************************************\
 *                             Object init                            *
\**********************************************************************/
G_DEFINE_TYPE_WITH_PRIVATE(MirageCdTextCoder, mirage_cdtext_coder, MIRAGE_TYPE_OBJECT)


static void mirage_cdtext_coder_init (MirageCdTextCoder *self)
{
    self->priv = mirage_cdtext_coder_get_instance_private(self);

    /* Specs say there can be 8 blocks max... */
    self->priv->num_blocks = 8;
    self->priv->blocks = g_new0(MirageCdTextCoderBlock, self->priv->num_blocks);
}

static void mirage_cdtext_coder_finalize (GObject *gobject)
{
    MirageCdTextCoder *self = MIRAGE_CDTEXT_CODER(gobject);

    /* Cleanup the data */
    mirage_cdtext_coder_cleanup(self);

    /* Free blocks data */
    g_free(self->priv->blocks);

    /* Chain up to the parent class */
    return G_OBJECT_CLASS(mirage_cdtext_coder_parent_class)->finalize(gobject);
}

static void mirage_cdtext_coder_class_init (MirageCdTextCoderClass *klass)
{
    GObjectClass *gobject_class = G_OBJECT_CLASS(klass);

    gobject_class->finalize = mirage_cdtext_coder_finalize;
}