path: root/widgets/misc/e-selection-model.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * e-selection-model.c: a Selection Model
 *
 * Author:
 *   Christopher James Lahey <clahey@ximian.com>
 *
 * (C) 2000, 2001 Ximian, Inc.
 */
#include <config.h>
#include <gtk/gtksignal.h>
#include "e-selection-model.h"
#include "gal/util/e-util.h"
#include <gdk/gdkkeysyms.h>

#define ESM_CLASS(e) ((ESelectionModelClass *)((GtkObject *)e)->klass)

#define PARENT_TYPE gtk_object_get_type ()

#define ONES ((guint32) 0xffffffff)

#define BOX(n) ((n) / 32)
#define OFFSET(n) (31 - ((n) % 32))
#define BITMASK(n) ((guint32)(((guint32) 0x1) << OFFSET((n))))
#define BITMASK_LEFT(n) ((((n) % 32) == 0) ? 0 : (ONES << (32 - ((n) % 32))))
#define BITMASK_RIGHT(n) ((guint32)(((guint32) ONES) >> ((n) % 32)))

static GtkObjectClass *e_selection_model_parent_class;

static void change_one_row(ESelectionModel *selection, int row, gboolean grow);
static void esm_select_single_row (ESelectionModel *selection, int row);

enum {
    CURSOR_CHANGED,
    CURSOR_ACTIVATED,
    SELECTION_CHANGED,
    LAST_SIGNAL
};

static guint e_selection_model_signals [LAST_SIGNAL] = { 0, };

enum {
    ARG_0,
    ARG_SORTER,
    ARG_CURSOR_ROW,
    ARG_CURSOR_COL,
    ARG_SELECTION_MODE,
    ARG_CURSOR_MODE,
};

static void
e_selection_model_insert_row_real(ESelectionModel *esm, int row)
{
    int box;
    int i;
    if(esm->row_count >= 0) {
        /* Add another word if needed. */
        if ((esm->row_count & 0x1f) == 0) {
            esm->selection = g_renew(gint, esm->selection, (esm->row_count >> 5) + 1);
            esm->selection[esm->row_count >> 5] = 0;
        }

        /* The box is the word that our row is in. */
        box = BOX(row);
        /* Shift all words to the right of our box right one bit. */
        for (i = esm->row_count >> 5; i > box; i--) {
            esm->selection[i] = (esm->selection[i] >> 1) | (esm->selection[i - 1] << 31);
        }

        /* Shift right half of box one bit to the right. */
        esm->selection[box] = (esm->selection[box] & BITMASK_LEFT(row)) | ((esm->selection[box] & BITMASK_RIGHT(row)) >> 1);
        esm->row_count ++;
    }
    if (esm->cursor_row >= row)
        esm->cursor_row ++;
}

static void
e_selection_model_delete_row_real(ESelectionModel *esm, int row)
{
    int box;
    int i;
    int last;
    int selected = FALSE;
    if(esm->row_count >= 0) {
        guint32 bitmask;
        box = row >> 5;
        last = esm->row_count >> 5;

        /* Build bitmasks for the left and right half of the box */
        bitmask = BITMASK_RIGHT(row) >> 1;
        selected = e_selection_model_is_row_selected(esm, row);
        /* Shift right half of box one bit to the left. */
        esm->selection[box] = (esm->selection[box] & BITMASK_LEFT(row))| ((esm->selection[box] & bitmask) << 1);

        /* Shift all words to the right of our box left one bit. */
        if (box < last) {
            esm->selection[box] &= esm->selection[box + 1] >> 31;

            for (i = box + 1; i < last; i++) {
                esm->selection[i] = (esm->selection[i] << 1) | (esm->selection[i + 1] >> 31);
            }
            /* this over-runs our memory! */
            /*esm->selection[i] = esm->selection[i] << 1; */
        }
        esm->row_count --;
        /* Remove the last word if not needed. */
        if ((esm->row_count & 0x1f) == 0) {
            esm->selection = g_renew(gint, esm->selection, esm->row_count >> 5);
        }
        if (selected && esm->mode == GTK_SELECTION_SINGLE) {
            esm_select_single_row (esm, row > 0 ? row - 1 : 0);
        }
    }
    if (esm->cursor_row >= row && esm->cursor_row > 0)
        esm->cursor_row --;
}

void
e_selection_model_delete_row(ESelectionModel *esm, int row)
{
    e_selection_model_delete_row_real(esm, row);
    gtk_signal_emit(GTK_OBJECT(esm),
            e_selection_model_signals [SELECTION_CHANGED]);
    gtk_signal_emit(GTK_OBJECT(esm),
            e_selection_model_signals [CURSOR_CHANGED], esm->cursor_row, esm->cursor_col);
}

void
e_selection_model_insert_row(ESelectionModel *esm, int row)
{
    e_selection_model_insert_row_real(esm, row);
    gtk_signal_emit(GTK_OBJECT(esm),
            e_selection_model_signals [SELECTION_CHANGED]);
    gtk_signal_emit(GTK_OBJECT(esm),
            e_selection_model_signals [CURSOR_CHANGED], esm->cursor_row, esm->cursor_col);
}

/* FIXME: Implement this more efficiently. */
void
e_selection_model_move_row(ESelectionModel *esm, int old_row, int new_row)
{
    gint selected = e_selection_model_is_row_selected(esm, old_row);
    gint cursor = esm->cursor_row == old_row;

    e_selection_model_delete_row_real(esm, old_row);
    e_selection_model_insert_row_real(esm, new_row);

    if (selected) {
        if (esm->mode == GTK_SELECTION_SINGLE)
            esm_select_single_row (esm, new_row);
        else
            change_one_row(esm, new_row, TRUE);
    }
    if (cursor) {
        esm->cursor_row = new_row;
    }
    gtk_signal_emit(GTK_OBJECT(esm),
            e_selection_model_signals [SELECTION_CHANGED]);
    gtk_signal_emit(GTK_OBJECT(esm),
            e_selection_model_signals [CURSOR_CHANGED], esm->cursor_row, esm->cursor_col);
}

inline static void
add_sorter(ESelectionModel *esm, ESorter *sorter)
{
    esm->sorter = sorter;
    if (sorter) {
        gtk_object_ref(GTK_OBJECT(sorter));
    }
}

inline static void
drop_sorter(ESelectionModel *esm)
{
    if (esm->sorter) {
        gtk_object_unref(GTK_OBJECT(esm->sorter));
    }
    esm->sorter = NULL;
}

static void
esm_destroy (GtkObject *object)
{
    ESelectionModel *esm;

    esm = E_SELECTION_MODEL (object);

    drop_sorter(esm);

    g_free(esm->selection);
}

static void
esm_get_arg (GtkObject *o, GtkArg *arg, guint arg_id)
{
    ESelectionModel *esm = E_SELECTION_MODEL (o);

    switch (arg_id){
    case ARG_SORTER:
        GTK_VALUE_OBJECT (*arg) = GTK_OBJECT(esm->sorter);
        break;

    case ARG_CURSOR_ROW:
        GTK_VALUE_INT(*arg) = esm->cursor_row;
        break;

    case ARG_CURSOR_COL:
        GTK_VALUE_INT(*arg) = esm->cursor_col;
        break;

    case ARG_SELECTION_MODE:
        GTK_VALUE_ENUM(*arg) = esm->mode;
        break;

    case ARG_CURSOR_MODE:
        GTK_VALUE_ENUM(*arg) = esm->cursor_mode;
        break;
    }
}

static void
esm_set_arg (GtkObject *o, GtkArg *arg, guint arg_id)
{
    ESelectionModel *esm = E_SELECTION_MODEL (o);
    
    switch (arg_id){
    case ARG_SORTER:
        drop_sorter(esm);
        add_sorter(esm, GTK_VALUE_OBJECT (*arg) ? E_SORTER(GTK_VALUE_OBJECT (*arg)) : NULL);
        break;

    case ARG_CURSOR_ROW:
        e_selection_model_do_something(esm, GTK_VALUE_INT(*arg), esm->cursor_col, 0);
        break;

    case ARG_CURSOR_COL:
        e_selection_model_do_something(esm, esm->cursor_row, GTK_VALUE_INT(*arg), 0);
        break;

    case ARG_SELECTION_MODE:
        esm->mode = GTK_VALUE_ENUM(*arg);
        if (esm->mode == GTK_SELECTION_SINGLE) {
            e_selection_model_do_something(esm, esm->cursor_row, esm->cursor_col, 0);
        }
        break;

    case ARG_CURSOR_MODE:
        esm->cursor_mode = GTK_VALUE_ENUM(*arg);
        break;
    }
}

static void
e_selection_model_init (ESelectionModel *selection)
{
    selection->selection = NULL;
    selection->row_count = -1;
    selection->selection_start_row = 0;
    selection->cursor_row = -1;
    selection->cursor_col = -1;
    selection->mode = GTK_SELECTION_MULTIPLE;
    selection->cursor_mode = E_CURSOR_SIMPLE;
}

static void
e_selection_model_class_init (ESelectionModelClass *klass)
{
    GtkObjectClass *object_class;

    e_selection_model_parent_class = gtk_type_class (gtk_object_get_type ());

    object_class = GTK_OBJECT_CLASS(klass);

    object_class->destroy = esm_destroy;
    object_class->get_arg = esm_get_arg;
    object_class->set_arg = esm_set_arg;

    e_selection_model_signals [CURSOR_CHANGED] =
        gtk_signal_new ("cursor_changed",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (ESelectionModelClass, cursor_changed),
                gtk_marshal_NONE__INT_INT,
                GTK_TYPE_NONE, 2, GTK_TYPE_INT, GTK_TYPE_INT);

    e_selection_model_signals [CURSOR_ACTIVATED] =
        gtk_signal_new ("cursor_activated",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (ESelectionModelClass, cursor_activated),
                gtk_marshal_NONE__INT_INT,
                GTK_TYPE_NONE, 2, GTK_TYPE_INT, GTK_TYPE_INT);

    e_selection_model_signals [SELECTION_CHANGED] =
        gtk_signal_new ("selection_changed",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (ESelectionModelClass, selection_changed),
                gtk_marshal_NONE__NONE,
                GTK_TYPE_NONE, 0);

    klass->cursor_changed    = NULL;
    klass->cursor_activated  = NULL;
    klass->selection_changed = NULL;

    gtk_object_class_add_signals (object_class, e_selection_model_signals, LAST_SIGNAL);

    gtk_object_add_arg_type ("ESelectionModel::sorter", GTK_TYPE_OBJECT,
                 GTK_ARG_READWRITE, ARG_SORTER);
    gtk_object_add_arg_type ("ESelectionModel::cursor_row", GTK_TYPE_INT,
                 GTK_ARG_READWRITE, ARG_CURSOR_ROW);
    gtk_object_add_arg_type ("ESelectionModel::cursor_col", GTK_TYPE_INT,
                 GTK_ARG_READWRITE, ARG_CURSOR_COL);
    gtk_object_add_arg_type ("ESelectionModel::selection_mode", GTK_TYPE_ENUM,
                 GTK_ARG_READWRITE, ARG_SELECTION_MODE);
    gtk_object_add_arg_type ("ESelectionModel::cursor_mode", GTK_TYPE_ENUM,
                 GTK_ARG_READWRITE, ARG_CURSOR_MODE);
}

E_MAKE_TYPE(e_selection_model, "ESelectionModel", ESelectionModel,
        e_selection_model_class_init, e_selection_model_init, PARENT_TYPE);

/** 
 * e_selection_model_is_row_selected
 * @selection: #ESelectionModel to check
 * @n: The row to check
 *
 * This routine calculates whether the given row is selected.
 *
 * Returns: %TRUE if the given row is selected
 */
gboolean
e_selection_model_is_row_selected (ESelectionModel *selection,
                   gint                 n)
{
    if (selection->row_count < n || selection->row_count == 0)
        return 0;
    else
        return (selection->selection[BOX(n)] >> OFFSET(n)) & 0x1;
}

/** 
 * e_selection_model_foreach
 * @selection: #ESelectionModel to traverse
 * @callback: The callback function to call back.
 * @closure: The closure
 *
 * This routine calls the given callback function once for each
 * selected row, passing closure as the closure.
 */
void 
e_selection_model_foreach     (ESelectionModel *selection,
                   EForeachFunc callback,
                   gpointer closure)
{
    int i;
    int last = (selection->row_count + 31) / 32;
    for (i = 0; i < last; i++) {
        if (selection->selection[i]) {
            int j;
            guint32 value = selection->selection[i];
            for (j = 0; j < 32; j++) {
                if (value & 0x80000000) {
                    callback(i * 32 + j, closure);
                }
                value <<= 1;
            }
        }
    }
}

#define OPERATE(object, i,mask,grow) ((grow) ? (((object)->selection[(i)]) |= ((guint32) ~(mask))) : (((object)->selection[(i)]) &= (mask)))

static void
change_one_row(ESelectionModel *selection, int row, gboolean grow)
{
    int i;
    i = BOX(row);

    OPERATE(selection, i, ~BITMASK(row), grow);
}

static void
change_selection(ESelectionModel *selection, int start, int end, gboolean grow)
{
    int i, last;
    if (start != end) {
        if (selection->sorter && e_sorter_needs_sorting(selection->sorter)) {
            for ( i = start; i < end; i++) {
                change_one_row(selection, e_sorter_sorted_to_model(selection->sorter, i), grow);
            }
        } else {
            i = BOX(start);
            last = BOX(end);

            if (i == last) {
                OPERATE(selection, i, BITMASK_LEFT(start) | BITMASK_RIGHT(end), grow);
            } else {
                OPERATE(selection, i, BITMASK_LEFT(start), grow);
                if (grow)
                    for (i ++; i < last; i++)
                        selection->selection[i] = ONES;
                else
                    for (i ++; i < last; i++)
                        selection->selection[i] = 0;
                OPERATE(selection, i, BITMASK_RIGHT(end), grow);
            }
        }
    }
}

static void
esm_select_single_row (ESelectionModel *selection, int row)
{
    int i;
    for (i = 0; i < ((selection->row_count + 31) / 32); i++) {
        if (!((i == BOX(row) && selection->selection[i] == BITMASK(row)) ||
              (i != BOX(row) && selection->selection[i] == 0))) {
            g_free(selection->selection);
            selection->selection = g_new0(gint, (selection->row_count + 31) / 32);
            selection->selection[BOX(row)] = BITMASK(row);

            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals [SELECTION_CHANGED]);
            break;
        }
    }

    selection->selection_start_row = row;
}

static void
esm_toggle_single_row (ESelectionModel *selection, int row)
{
    if (selection->selection[BOX(row)] & BITMASK(row))
        selection->selection[BOX(row)] &= ~BITMASK(row);
    else
        selection->selection[BOX(row)] |= BITMASK(row);
    selection->selection_start_row = row;
    gtk_signal_emit(GTK_OBJECT(selection),
            e_selection_model_signals [SELECTION_CHANGED]);
}

static void
esm_move_selection_end (ESelectionModel *selection, int row)
{
    int old_start;
    int old_end;
    int new_start;
    int new_end;
    if (selection->sorter && e_sorter_needs_sorting(selection->sorter)) {
        old_start = MIN (e_sorter_model_to_sorted(selection->sorter, selection->selection_start_row),
                 e_sorter_model_to_sorted(selection->sorter, selection->cursor_row));
        old_end = MAX (e_sorter_model_to_sorted(selection->sorter, selection->selection_start_row),
                   e_sorter_model_to_sorted(selection->sorter, selection->cursor_row)) + 1;
        new_start = MIN (e_sorter_model_to_sorted(selection->sorter, selection->selection_start_row),
                 e_sorter_model_to_sorted(selection->sorter, row));
        new_end = MAX (e_sorter_model_to_sorted(selection->sorter, selection->selection_start_row),
                   e_sorter_model_to_sorted(selection->sorter, row)) + 1;
    } else {
        old_start = MIN (selection->selection_start_row, selection->cursor_row);
        old_end = MAX (selection->selection_start_row, selection->cursor_row) + 1;
        new_start = MIN (selection->selection_start_row, row);
        new_end = MAX (selection->selection_start_row, row) + 1;
    }
    /* This wouldn't work nearly so smoothly if one end of the selection weren't held in place. */
    if (old_start < new_start)
        change_selection(selection, old_start, new_start, FALSE);
    if (new_start < old_start)
        change_selection(selection, new_start, old_start, TRUE);
    if (old_end < new_end)
        change_selection(selection, old_end, new_end, TRUE);
    if (new_end < old_end)
        change_selection(selection, new_end, old_end, FALSE);
    gtk_signal_emit(GTK_OBJECT(selection),
            e_selection_model_signals [SELECTION_CHANGED]);
}

static void
esm_set_selection_end (ESelectionModel *selection, int row)
{
    esm_select_single_row(selection, selection->selection_start_row);
    selection->cursor_row = selection->selection_start_row;
    esm_move_selection_end(selection, row);
}

/** 
 * e_selection_model_do_something
 * @selection: #ESelectionModel to do something to.
 * @row: The row to do something in.
 * @col: The col to do something in.
 * @state: The state in which to do something.
 *
 * This routine does whatever is appropriate as if the user clicked
 * the mouse in the given row and column.
 */
void
e_selection_model_do_something (ESelectionModel *selection,
                guint                 row,
                guint                 col,
                GdkModifierType       state)
{
    gint shift_p = state & GDK_SHIFT_MASK;
    gint ctrl_p = state & GDK_CONTROL_MASK;

    if (row == -1 && col != -1)
        row = 0;
    if (col == -1 && row != -1)
        col = 0;

    if (selection->row_count < 0) {
        selection->row_count = e_selection_model_get_row_count(selection);
        if (selection->row_count < 0)
            return;
        g_free(selection->selection);
        selection->selection = g_new0(gint, (selection->row_count + 31) / 32);
    }
    if (selection->row_count >= 0 && row < selection->row_count) {
        switch (selection->mode) {
        case GTK_SELECTION_SINGLE:
            esm_select_single_row (selection, row);
            break;
        case GTK_SELECTION_BROWSE:
        case GTK_SELECTION_MULTIPLE:
        case GTK_SELECTION_EXTENDED:
            if (shift_p) {
                esm_set_selection_end (selection, row);
            } else {
                if (ctrl_p) {
                    esm_toggle_single_row (selection, row);
                } else {
                    esm_select_single_row (selection, row);
                }
            }
            break;
        }
        if (selection->cursor_row != row ||
            selection->cursor_col != col) {
            selection->cursor_row = row;
            selection->cursor_col = col;
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_CHANGED], row, col);
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_ACTIVATED], row, col);
        }
    }
}

/** 
 * e_selection_model_maybe_do_something
 * @selection: #ESelectionModel to do something to.
 * @row: The row to do something in.
 * @col: The col to do something in.
 * @state: The state in which to do something.
 *
 * If this row is selected, this routine just moves the cursor row and
 * column.  Otherwise, it does the same thing as
 * e_selection_model_do_something().  This is for being used on
 * right clicks and other events where if the user hit the selection,
 * they don't want it to change.
 */
void
e_selection_model_maybe_do_something      (ESelectionModel *selection,
                         guint                 row,
                         guint                 col,
                         GdkModifierType       state)
{
    if (e_selection_model_is_row_selected(selection, row)) {
        selection->cursor_row = row;
        selection->cursor_col = col;
    } else {
        e_selection_model_do_something(selection, row, col, state);
    }
}

static gint
move_selection (ESelectionModel *selection,
        gboolean              up,
        GdkModifierType       state)
{
    int row = selection->cursor_row;
    int col = selection->cursor_col;
    int cursor_activated = TRUE;

    gint shift_p = state & GDK_SHIFT_MASK;
    gint ctrl_p = state & GDK_CONTROL_MASK;

    row = e_sorter_model_to_sorted(selection->sorter, row);
    if (up)
        row--;
    else
        row++;
    if (row < 0)
        row = 0;
    if (row >= selection->row_count)
        row = selection->row_count - 1;
    row = e_sorter_sorted_to_model(selection->sorter, row);

    switch (selection->mode) {
    case GTK_SELECTION_BROWSE:
        if (shift_p) {
            esm_set_selection_end (selection, row);
        } else if (!ctrl_p) {
            esm_select_single_row (selection, row);
        } else
            cursor_activated = FALSE;
        break;
    case GTK_SELECTION_SINGLE:
    case GTK_SELECTION_MULTIPLE:
    case GTK_SELECTION_EXTENDED:
        esm_select_single_row (selection, row);
        break;
    }
    if (row != -1) {
        selection->cursor_row = row;
        gtk_signal_emit(GTK_OBJECT(selection),
                e_selection_model_signals[CURSOR_CHANGED], row, col);
        if (cursor_activated)
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_ACTIVATED], row, col);
    }
    return TRUE;
}

/** 
 * e_selection_model_key_press
 * @selection: #ESelectionModel to affect.
 * @key: The event.
 *
 * This routine does whatever is appropriate as if the user pressed
 * the given key.
 *
 * Returns: %TRUE if the #ESelectionModel used the key.
 */
gint
e_selection_model_key_press      (ESelectionModel *selection,
                    GdkEventKey          *key)
{
    switch (key->keyval) {
    case GDK_Up:
        return move_selection(selection, TRUE, key->state);
        break;
    case GDK_Down:
        return move_selection(selection, FALSE, key->state);
        break;
    case GDK_space:
    case GDK_KP_Space:
        if (selection->mode != GTK_SELECTION_SINGLE) {
            esm_toggle_single_row (selection, selection->cursor_row);
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_ACTIVATED], selection->cursor_row, selection->cursor_col);
            return TRUE;
        }
        break;
    case GDK_Return:
    case GDK_KP_Enter:
        if (selection->mode != GTK_SELECTION_SINGLE) {
            esm_select_single_row (selection, selection->cursor_row);
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_ACTIVATED], selection->cursor_row, selection->cursor_col);
            return TRUE;
        }
        break;
    case GDK_Home:
    case GDK_KP_Home:
        if (selection->cursor_mode == E_CURSOR_LINE) {
            int row = 0;

            row = e_sorter_sorted_to_model(selection->sorter, row);
            selection->cursor_row = row;

            esm_select_single_row (selection, selection->cursor_row);
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_CHANGED], selection->cursor_row, selection->cursor_col);
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_ACTIVATED], selection->cursor_row, selection->cursor_col);
            return TRUE;
        }
        break;
    case GDK_End:
    case GDK_KP_End:
        if (selection->cursor_mode == E_CURSOR_LINE) {
            int row = selection->row_count - 1;

            row = e_sorter_sorted_to_model(selection->sorter, row);
            selection->cursor_row = row;

            esm_select_single_row (selection, selection->cursor_row);
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_CHANGED], selection->cursor_row, selection->cursor_col);
            gtk_signal_emit(GTK_OBJECT(selection),
                    e_selection_model_signals[CURSOR_ACTIVATED], selection->cursor_row, selection->cursor_col);
            return TRUE;
        }
        break;
    }
    return FALSE;
}

/** 
 * e_selection_model_clear
 * @selection: #ESelectionModel to clear
 *
 * This routine clears the selection to no rows selected.
 */
void
e_selection_model_clear(ESelectionModel *selection)
{
    g_free(selection->selection);
    selection->selection = NULL;
    selection->row_count = -1;
    selection->cursor_row = -1;
    selection->cursor_col = -1;
    gtk_signal_emit(GTK_OBJECT(selection),
            e_selection_model_signals [CURSOR_CHANGED], -1, -1);
    gtk_signal_emit(GTK_OBJECT(selection),
            e_selection_model_signals [SELECTION_CHANGED]);
}

#define PART(x,n) (((x) & (0x01010101 << n)) >> n)
#define SECTION(x, n) (((x) >> (n * 8)) & 0xff)

/** 
 * e_selection_model_selected_count
 * @selection: #ESelectionModel to count
 *
 * This routine calculates the number of rows selected.
 *
 * Returns: The number of rows selected in the given model.
 */
gint
e_selection_model_selected_count (ESelectionModel *selection)
{
    gint count;
    int i;
    int last;

    if (!selection->selection)
        return 0;

    count = 0;

    last = BOX(selection->row_count - 1);

    for (i = 0; i <= last; i++) {
        int j;
        guint32 thiscount = 0;
        for (j = 0; j < 8; j++)
            thiscount += PART(selection->selection[i], j);
        for (j = 0; j < 4; j++)
            count += SECTION(thiscount, j);
    }

    return count;
}

/** 
 * e_selection_model_select_all
 * @selection: #ESelectionModel to select all
 *
 * This routine selects all the rows in the given
 * #ESelectionModel.
 */
void
e_selection_model_select_all (ESelectionModel *selection)
{
    int i;
    
    if (selection->row_count < 0) {
        selection->row_count = e_selection_model_get_row_count(selection);
        if (selection->row_count < 0)
            return;
        g_free (selection->selection);
        selection->selection = g_new0 (gint, (selection->row_count + 31) / 32);
    }
    
    if (!selection->selection)
        selection->selection = g_new0 (gint, (selection->row_count + 31) / 32);
    
    for (i = 0; i < (selection->row_count + 31) / 32; i ++) {
        selection->selection[i] = ONES;
    }

    /* need to zero out the bits corresponding to the rows not
       selected in the last full 32 bit mask */
    if (selection->row_count % 32) {
        int unselected_mask = 0;
        int num_unselected_in_last_byte = 32 - selection->row_count % 32;

        for (i = 0; i < num_unselected_in_last_byte; i ++)
            unselected_mask |= 1 << i;

        selection->selection[(selection->row_count + 31) / 32 - 1] &= ~unselected_mask;
    }

    selection->cursor_col = 0;
    selection->cursor_row = 0;
    selection->selection_start_row = 0;
    gtk_signal_emit (GTK_OBJECT (selection),
             e_selection_model_signals [CURSOR_CHANGED], 0, 0);
    gtk_signal_emit (GTK_OBJECT (selection),
             e_selection_model_signals [SELECTION_CHANGED]);
}

/** 
 * e_selection_model_invert_selection
 * @selection: #ESelectionModel to invert
 *
 * This routine inverts all the rows in the given
 * #ESelectionModel.
 */
void
e_selection_model_invert_selection (ESelectionModel *selection)
{
    int i;
    
    if (selection->row_count < 0) {
        selection->row_count = e_selection_model_get_row_count (selection);
        if (selection->row_count < 0)
            return;
        g_free (selection->selection);
        selection->selection = g_new0 (gint, (selection->row_count + 31) / 32);
    }
    
    if (!selection->selection)
        selection->selection = g_new0 (gint, (selection->row_count + 31) / 32);
    
    for (i = 0; i < (selection->row_count + 31) / 32; i ++) {
        selection->selection[i] = ~selection->selection[i];
    }
    
    selection->cursor_col = -1;
    selection->cursor_row = -1;
    selection->selection_start_row = 0;
    gtk_signal_emit (GTK_OBJECT (selection),
             e_selection_model_signals [CURSOR_CHANGED], -1, -1);
    gtk_signal_emit (GTK_OBJECT (selection),
             e_selection_model_signals [SELECTION_CHANGED]);
}

int
e_selection_model_get_row_count (ESelectionModel *selection)
{
    g_return_val_if_fail(selection != NULL, 0);
    g_return_val_if_fail(E_IS_SELECTION_MODEL(selection), 0);

    if (ESM_CLASS(selection)->get_row_count)
        return ESM_CLASS(selection)->get_row_count (selection);
    else
        return 0;
}