gsegyfileaccessor.c

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    guint8 *trace_buffer;

    if (double_buffer)
        data = (gfloat*)g_try_malloc (2 * private->number_of_samples * traces_num * sizeof (gfloat));
    else
        data = (gfloat*)g_try_malloc (private->number_of_samples * (traces_num + 1) * sizeof (gfloat));

    if (NULL == data) {
       if (file_error)
           file_error->id = G_SEGY_FILE_MEMORY_ALLOCATION_FAIL;
        return NULL;
    }

    trace_buffer = (guint8*)&data[private->number_of_samples * traces_num];

    fd = g_io_channel_unix_get_fd (private->io_channel);

#if defined LINUX || defined WIN32
    if (private->file_mutex)
        g_mutex_lock (private->file_mutex);
#endif

    for (i = 0; i < traces_num; i++) {
#if defined LINUX || defined WIN32
        seek_pos = lseek (fd, g_array_index (private->trace_positions, guint64, traces_indices[i]), SEEK_SET);
        if (seek_pos == (guint64)LSEEK_ERR) {
#else
        status = g_io_channel_seek_position (private->io_channel,
                                             g_array_index (private->trace_positions, guint64, traces_indices[i]),
                                             G_SEEK_SET, &gerror);
        if (status != G_IO_STATUS_NORMAL) {
#endif
            if (file_error) {
                if (status == G_IO_STATUS_EOF)
                    file_error->id = G_SEGY_FILE_PREMATURE_EOF;
                else
                    file_error->id = G_SEGY_FILE_READ_ERROR;                  
                file_error->gerror = gerror;
            }
            break;
        }

#if defined LINUX || defined WIN32
        bytes_read = read (fd, trace_buffer, private->trace_header_size);
        if (bytes_read != private->trace_header_size) {
            if (bytes_read && file_error) {
                file_error->id = G_SEGY_FILE_PREMATURE_EOF;
#else
        status = g_io_channel_read_chars (private->io_channel, trace_buffer, private->trace_header_size,
                                          &bytes_read, &gerror);
        if (status != G_IO_STATUS_NORMAL || bytes_read != private->trace_header_size) {
            if (file_error) {
                if (status == G_IO_STATUS_EOF && bytes_read != 0)
                    file_error->id = G_SEGY_FILE_PREMATURE_EOF;
                else
                    file_error->id = G_SEGY_FILE_READ_ERROR;                  
                file_error->gerror = gerror;
#endif
            }
            break;
        }

        g_segy_format_wizard_get_number_of_samples (private->format_wizard, trace_buffer, &number_of_samples);
        samples_to_read = number_of_samples > private->number_of_samples || 0 == number_of_samples
                          ? private->number_of_samples : number_of_samples;
        bytes_to_read = samples_to_read * private->sample_size;
#if defined LINUX || defined WIN32
        bytes_read = read (fd, trace_buffer, bytes_to_read);
        if (bytes_read != bytes_to_read) {
            if (file_error)
                file_error->id = G_SEGY_FILE_READ_ERROR;
#else
        status = g_io_channel_read_chars (private->io_channel, trace_buffer, bytes_to_read,
                                          &bytes_read, &gerror);
        if (status != G_IO_STATUS_NORMAL || bytes_read != bytes_to_read) {
            if (file_error) {
                if (status == G_IO_STATUS_EOF && bytes_read != 0)
                    file_error->id = G_SEGY_FILE_PREMATURE_EOF;
                else
                    file_error->id = G_SEGY_FILE_READ_ERROR;                  
                file_error->gerror = gerror;
            }
#endif
            break;
        }
        g_segy_format_wizard_decode_trace (private->format_wizard, private->sample_id, samples_to_read,
                                           trace_buffer, &data[trace_num * private->number_of_samples]);
        if (samples_to_read < private->number_of_samples) {
           for (j = samples_to_read; j < private->number_of_samples; j++)
               data[trace_num * private->number_of_samples + j] = 0;
        }
        trace_num++;
    }

    if (0 == trace_num) {
        g_free (data);
        return NULL;
    }

#if defined LINUX || defined WIN32
    if (private->file_mutex)
        g_mutex_unlock (private->file_mutex);
#endif

    if (slow_num)
        *slow_num = trace_num;
    if (fast_num)
        *fast_num = private->number_of_samples;
    return data;
}

static void g_segy_file_accessor_init (GSEGYFileAccessor *self) {
    GSEGYFileAccessorPrivate *private = G_SEGY_FILE_ACCESSOR_GET_PRIVATE (self);

    private->format_wizard = NULL;
    private->io_channel = NULL;
    private->format_wizard = NULL;
    private->ebcdic_header = NULL;
    private->binary_header = NULL;

    private->sorting_contents = NULL;
    private->trace_positions = NULL;

    private->trace_buffer = NULL;
    private->trace_buffer_size = 0;

    private->sorting_data_buffer = NULL;

    if (g_thread_supported ())
        private->file_mutex = g_mutex_new ();

#ifdef DEBUG
    g_print ("<GSEGYFileAccessor is inited>\n");
#endif
}

static void g_segy_file_accessor_finalize (GObject *object) {
    GSEGYFileAccessorPrivate *private = G_SEGY_FILE_ACCESSOR_GET_PRIVATE (G_SEGY_FILE_ACCESSOR (object));

    if (private->format_wizard)
        g_object_unref (G_OBJECT (private->format_wizard));
    if (private->io_channel)
        g_io_channel_unref (private->io_channel);

    if (private->ebcdic_header_size)
        g_free (private->ebcdic_header);
    if (private->binary_header_size)
        g_free (private->binary_header);

    if (private->sorting_contents)
        g_array_free (private->sorting_contents, TRUE);
    if (private->trace_positions)
        g_array_free (private->trace_positions, TRUE);

    if (private->trace_buffer)
        g_free (private->trace_buffer);

    if (private->sorting_data_buffer)
        g_free (private->sorting_data_buffer);

    if (private->file_mutex)
        g_mutex_free (private->file_mutex);

#ifdef DEBUG
    g_print ("<GSEGYFileAccessor is finalized>\n");
#endif
    if (G_OBJECT_CLASS (g_segy_file_accessor_parent_class)->finalize)
        G_OBJECT_CLASS (g_segy_file_accessor_parent_class)->finalize (object);
}

enum {
    PROP_0,
    PROP_IO_CHANNEL,
    PROP_FORMAT_WIZARD
};

static void g_segy_file_accessor_set_property (GObject *object, guint prop_id,
                                               const GValue *value, GParamSpec *pspec) {
    GSEGYFileAccessorPrivate *private = G_SEGY_FILE_ACCESSOR_GET_PRIVATE (G_SEGY_FILE_ACCESSOR (object));

    switch (prop_id) {
        case PROP_IO_CHANNEL: {
            GIOChannel *io_channel = (GIOChannel*)g_value_get_pointer (value);
            private->io_channel = io_channel;
            g_io_channel_ref (private->io_channel);
            if (private->format_wizard)
                g_segy_file_accessor_setup (G_SEGY_FILE_ACCESSOR (object));
            g_object_notify (object, "io_channel");
            }
            break;
        case PROP_FORMAT_WIZARD: {
            GSEGYFormatWizard *format_wizard = G_SEGY_FORMAT_WIZARD (g_value_get_object (value));
            private->format_wizard = format_wizard;
            g_object_ref (G_OBJECT (private->format_wizard));
            if (private->io_channel)
                g_segy_file_accessor_setup (G_SEGY_FILE_ACCESSOR (object));
            g_object_notify (object, "format_wizard");
            }
            break;
        default:
            G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
            break;
    }
}

static void g_segy_file_accessor_get_property (GObject *object, guint prop_id,
                                               GValue *value, GParamSpec *pspec) {
    GSEGYFileAccessorPrivate *private = G_SEGY_FILE_ACCESSOR_GET_PRIVATE (G_SEGY_FILE_ACCESSOR (object));

    switch (prop_id) {
        case PROP_IO_CHANNEL:
            g_value_set_pointer (value, private->io_channel);
            break;
        case PROP_FORMAT_WIZARD:
            g_value_set_object (value, private->format_wizard);
            break;
        default:
            G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
            break;
    }
}

static void g_segy_file_accessor_class_init (GSEGYFileAccessorClass *klass) {
    GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

    g_type_class_add_private (klass, sizeof (GSEGYFileAccessorPrivate));

    gobject_class->finalize = (GObjectFinalizeFunc) g_segy_file_accessor_finalize;
    gobject_class->set_property = g_segy_file_accessor_set_property;
    gobject_class->get_property = g_segy_file_accessor_get_property;

    klass->scan_fraction = NULL;

    klass->scan_fraction_id = g_signal_new ("scan_fraction",
                                            G_TYPE_FROM_CLASS ((gpointer)G_OBJECT_CLASS (klass)),
                                            G_SIGNAL_RUN_LAST,
                                            G_STRUCT_OFFSET (GSEGYFileAccessorClass, scan_fraction),
                                            NULL, NULL,
                                            g_segy_marshal_BOOLEAN__FLOAT_BOXED,
                                            G_TYPE_BOOLEAN, 2,
                                            G_TYPE_FLOAT, G_TYPE_POINTER);

    g_object_class_install_property (gobject_class,
                                     PROP_IO_CHANNEL,
                                     g_param_spec_pointer ("io_channel", "IOChannel",
                                     "System object describing opened files",
                                     G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY));

    g_object_class_install_property (gobject_class,
                                     PROP_FORMAT_WIZARD,
                                     g_param_spec_object ("format_wizard", "FormatWizard",
                                     "Object responsible for the knowledge of how to read opened files",
                                     G_SEGY_TYPE_FORMAT_WIZARD,
                                     G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY));

#ifdef DEBUG
    g_print ("<GSEGYFileAccessor class is inited>\n");
#endif
}