libsmartcols: implement title of table

Reference: https://github.com/karelzak/util-linux/issues/258
Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>

libsmartcols/src/libsmartcols.h.in

@@ -86,6 +86,15 @@ enum {
 	SCOLS_FL_HIDDEN	     = (1 << 5),   /* maintain data, but don't print */
 };
 
+/*
+ * Position of table's title
+ */
+enum {
+	SCOLS_TITLE_LEFT = 0,
+	SCOLS_TITLE_CENTER,
+	SCOLS_TITLE_RIGHT
+};
+
 extern struct libscols_iter *scols_new_iter(int direction);
 extern void scols_free_iter(struct libscols_iter *itr);
 extern void scols_reset_iter(struct libscols_iter *itr, int direction);
@@ -177,6 +186,7 @@ extern struct libscols_line *scols_copy_line(struct libscols_line *ln);
 /* table */
 extern int scols_table_colors_wanted(struct libscols_table *tb);
 extern int scols_table_set_name(struct libscols_table *tb, const char *name);
+extern int scols_table_set_title(struct libscols_table *tb, const char *title, int position, const char *color);
 extern int scols_table_is_raw(struct libscols_table *tb);
 extern int scols_table_is_ascii(struct libscols_table *tb);
 extern int scols_table_is_json(struct libscols_table *tb);

libsmartcols/src/libsmartcols.sym

@@ -127,4 +127,5 @@ global:
 	scols_line_refer_column_data;
 	scols_line_set_column_data;
 	scols_table_enable_nowrap;
+	scols_table_set_title;
 } SMARTCOLS_2.27;

libsmartcols/src/smartcolsP.h

@@ -125,7 +125,8 @@ enum {
  */
 struct libscols_table {
 	int	refcount;
-	char	*name;		/* optional table table */
+	char	*name;		/* optional table name (for JSON) */
+	char	*title;		/* optional table title (for humans) */
 	size_t	ncols;		/* number of columns */
 	size_t  ntreecols;	/* number of columns with SCOLS_FL_TREE */
 	size_t	nlines;		/* number of lines */
@@ -151,6 +152,8 @@ struct libscols_table {
 			maxout		:1,	/* maximalize output */
 			no_headings	:1,	/* don't print header */
 			no_wrap		:1;	/* never wrap lines */
+	unsigned int	title_pos;		/* title position */
+	char		*title_color;		/* title color */
 };
 
 #define IS_ITER_FORWARD(_i)	((_i)->direction == SCOLS_ITER_FORWARD)

libsmartcols/src/table.c

@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2010-2014 Karel Zak <kzak@redhat.com>
  * Copyright (C) 2014 Ondrej Oprala <ooprala@redhat.com>
+ * Copytight (C) 2016 Igor Gnatenko <i.gnatenko.brain@gmail.com>
  *
  * This file may be redistributed under the terms of the
  * GNU Lesser General Public License.
@@ -121,6 +122,52 @@ int scols_table_set_name(struct libscols_table *tb, const char *name)
 	return 0;
 }
 
+/**
+ * scols_table_set_title:
+ * @tb: a pointer to a struct libscols_table instance
+ * @title: a title
+ * @position: a position
+ * @color: color name or ESC sequence
+ *
+ * The table title is used to print header of table.
+ *
+ * Returns: 0, a negative number in case of an error.
+ */
+int scols_table_set_title(struct libscols_table *tb, const char *title, int position, const char *color)
+{
+	char *p = NULL;
+
+	if (!tb)
+		return -EINVAL;
+
+	if (title) {
+		p = strdup(title);
+		if (!p)
+			return -ENOMEM;
+	}
+	free(tb->title);
+	tb->title = p;
+
+	tb->title_pos = position;
+
+	p = NULL;
+	if (color) {
+		if (isalpha(*color)) {
+			color = color_sequence_from_colorname(color);
+
+			if (!color)
+				return -EINVAL;
+		}
+		p = strdup(color);
+		if (!p)
+			return -ENOMEM;
+	}
+	free(tb->title_color);
+	tb->title_color = p;
+
+	return 0;
+}
+
 /**
  * scols_table_add_column:
  * @tb: a pointer to a struct libscols_table instance

libsmartcols/src/table_print.c

@@ -2,6 +2,7 @@
  * table.c - functions handling the data at the table level
  *
  * Copyright (C) 2010-2014 Karel Zak <kzak@redhat.com>
+ * Copyright (C) 2016 Igor Gnatenko <i.gnatenko.brain@gmail.com>
  *
  * This file may be redistributed under the terms of the
  * GNU Lesser General Public License.
@@ -544,6 +545,55 @@ static int print_line(struct libscols_table *tb,
 	return 0;
 }
 
+static void print_title(struct libscols_table *tb)
+{
+	int i = 0;
+	size_t len;
+
+	assert(tb);
+
+	if (!tb->title)
+		return;
+
+	len = strlen(tb->title);
+
+	DBG(TAB, ul_debugobj(tb, "printing title"));
+
+	if (tb->title_color)
+		fputs(tb->title_color, tb->out);
+
+	switch (tb->title_pos) {
+	case SCOLS_TITLE_LEFT:
+		fputs(tb->title, tb->out);
+
+		for (i = len; i < tb->termwidth; i++)
+			fputs(" ", tb->out);
+
+		break;
+	case SCOLS_TITLE_CENTER:
+		for (i = 0; i <= (tb->termwidth - len) / 2; i++)
+			fputs(" ", tb->out);
+
+		fputs(tb->title, tb->out);
+		i += len;
+
+		for (; i < tb->termwidth; i++)
+			fputs(" ", tb->out);
+
+		break;
+	case SCOLS_TITLE_RIGHT:
+		for (i = 0; i < tb->termwidth - len; i++)
+			fputs(" ", tb->out);
+
+		fputs(tb->title, tb->out);
+
+		break;
+	}
+
+	if (tb->title_color)
+		fputs(UL_COLOR_RESET, tb->out);
+}
+
 static int print_header(struct libscols_table *tb, struct libscols_buffer *buf)
 {
 	int rc = 0;
@@ -1074,6 +1124,8 @@ int scols_print_table(struct libscols_table *tb)
 
 	fput_table_open(tb);
 
+	print_title(tb);
+
 	rc = print_header(tb, buf);
 	if (rc)
 		goto done;