btrfs-progs: Add helpers functions to handle the printing of data in tabular format

This patch adds some functions to manage the printing of the data in
tabular format.

The function
	struct string_table *table_create(int columns, int rows)
creates an (empty) table.

The functions
	char *table_printf(struct string_table *tab, int column,
		int row, char *fmt, ...)
	char *table_vprintf(struct string_table *tab, int column,
		int row, char *fmt, va_list ap)
populate the table with text. To align the text to the left, the text
shall be prefixed with '<', otherwise the text shall be prefixed by a
'>'. If the first character is a '=', the the text is replace by a
sequence of '=' to fill the column width.

The function
	void table_free(struct string_table *)
frees all the data associated to the table.

The function
	void table_dump(struct string_table *tab)
prints the table on stdout.

Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
Signed-off-by: David Sterba <dsterba@suse.cz>

Makefile

@@ -10,7 +10,7 @@ objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
 	  root-tree.o dir-item.o file-item.o inode-item.o inode-map.o \
 	  extent-cache.o extent_io.o volumes.o utils.o repair.o \
 	  qgroup.o raid6.o free-space-cache.o list_sort.o props.o \
-	  ulist.o qgroup-verify.o backref.o
+	  ulist.o qgroup-verify.o backref.o string-table.o
 cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
 	       cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \
 	       cmds-quota.o cmds-qgroup.o cmds-replace.o cmds-check.o \

string-table.c

@@ -0,0 +1,156 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * 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., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include "string-table.h"
+
+/*
+ *  This function create an array of char * which will represent a table
+ */
+struct string_table *table_create(int columns, int rows)
+{
+	struct string_table *p;
+	int size;
+
+	size = sizeof( struct string_table ) +
+		rows * columns* sizeof(char *);
+	p = calloc(1, size);
+
+	if (!p) return NULL;
+
+	p->ncols = columns;
+	p->nrows = rows;
+
+	return p;
+}
+
+/*
+ * This function is like a vprintf, but store the results in a cell of
+ * the table.
+ * If fmt  starts with '<', the text is left aligned; if fmt starts with
+ * '>' the text is right aligned. If fmt is equal to '=' the text will
+ * be replaced by a '=====' dimensioned on the basis of the column width
+ */
+char *table_vprintf(struct string_table *tab, int column, int row,
+			  char *fmt, va_list ap)
+{
+	int idx = tab->ncols*row+column;
+	char *msg = calloc(100, sizeof(char));
+
+	if (!msg)
+		return NULL;
+
+	if (tab->cells[idx])
+		free(tab->cells[idx]);
+	tab->cells[idx] = msg;
+	vsnprintf(msg, 99, fmt, ap);
+
+	return msg;
+}
+
+
+/*
+ * This function is like a printf, but store the results in a cell of
+ * the table.
+ */
+char *table_printf(struct string_table *tab, int column, int row,
+			  char *fmt, ...)
+{
+	va_list ap;
+	char *ret;
+
+	va_start(ap, fmt);
+	ret = table_vprintf(tab, column, row, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+/*
+ * This function dumps the table. Every "=" string will be replaced by
+ * a "=======" length as the column
+ */
+void table_dump(struct string_table *tab)
+{
+	int	sizes[tab->ncols];
+	int	i, j;
+
+	for (i = 0 ; i < tab->ncols ; i++) {
+		sizes[i] = 0;
+		for (j = 0 ; j < tab->nrows ; j++) {
+			int idx = i + j*tab->ncols;
+			int s;
+
+			if (!tab->cells[idx])
+				continue;
+
+			s = strlen(tab->cells[idx]) - 1;
+			if (s < 1 || tab->cells[idx][0] == '=')
+				continue;
+
+			if (s > sizes[i])
+				sizes[i] = s;
+		}
+	}
+
+
+	for (j = 0 ; j < tab->nrows ; j++) {
+		for (i = 0 ; i < tab->ncols ; i++) {
+
+			int idx = i + j*tab->ncols;
+			char *s = tab->cells[idx];
+
+			if (!s|| !strlen(s)) {
+				printf("%*s", sizes[i], "");
+			} else if (s && s[0] == '=') {
+				int k = sizes[i];
+				while(k--)
+					putchar('=');
+			} else {
+				printf("%*s",
+					s[0] == '<' ? -sizes[i] : sizes[i],
+					s+1);
+			}
+			if (i != (tab->ncols - 1))
+				putchar(' ');
+		}
+		putchar('\n');
+	}
+
+}
+
+/*
+ *  Deallocate a tabular and all its content
+ */
+
+void table_free(struct string_table *tab)
+{
+
+	int	i, count;
+
+	count = tab->ncols * tab->nrows;
+
+	for (i=0 ; i < count ; i++)
+		if (tab->cells[i])
+			free(tab->cells[i]);
+
+	free(tab);
+
+}

string-table.h

@@ -0,0 +1,36 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * 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., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef STRING_TABLE_H
+#define STRING_TABLE_H
+
+struct string_table {
+
+	int	ncols, nrows;
+	char	*cells[];
+
+};
+
+
+struct string_table *table_create(int columns, int rows);
+char *table_printf(struct string_table *tab, int column, int row,
+			  char *fmt, ...);
+char *table_vprintf(struct string_table *tab, int column, int row,
+			  char *fmt, va_list ap);
+void table_dump(struct string_table *tab);
+void table_free(struct string_table *);
+
+#endif