libsmartcols: add scols_table_print_range()

Signed-off-by: Karel Zak <kzak@redhat.com>

6 files changed, 142 insertions, 51 deletions

diff --git a/libsmartcols/docs/libsmartcols-sections.txt b/libsmartcols/docs/libsmartcols-sections.txt
index 6289e3a2f..4ac129141 100644
--- a/libsmartcols/docs/libsmartcols-sections.txt
+++ b/libsmartcols/docs/libsmartcols-sections.txt
@@ -143,6 +143,7 @@ scols_unref_table
 <FILE>table_print</FILE>
 scols_print_table
 scols_print_table_to_string
+scols_table_print_range
 </SECTION>
 
 <SECTION>
diff --git a/libsmartcols/samples/tree.c b/libsmartcols/samples/tree.c
index 52be7fbd5..d2afc4717 100644
--- a/libsmartcols/samples/tree.c
+++ b/libsmartcols/samples/tree.c
@@ -142,13 +142,15 @@ static void add_lines(struct libscols_table *tb, const char *dirname)
 static void __attribute__((__noreturn__)) usage(FILE *out)
 {
 	fprintf(out, " %s [options] [<dir> ...]\n\n", program_invocation_short_name);
-	fputs(" -c, --csv            display a csv-like output\n", out);
-	fputs(" -i, --ascii          use ascii characters only\n", out);
-	fputs(" -l, --list           use list format output\n", out);
-	fputs(" -n, --noheadings     don't print headings\n", out);
-	fputs(" -p, --pairs          use key=\"value\" output format\n", out);
-	fputs(" -J, --json           use JSON output format\n", out);
-	fputs(" -r, --raw            use raw output format\n", out);
+	fputs(" -c, --csv               display a csv-like output\n", out);
+	fputs(" -i, --ascii             use ascii characters only\n", out);
+	fputs(" -l, --list              use list format output\n", out);
+	fputs(" -n, --noheadings        don't print headings\n", out);
+	fputs(" -p, --pairs             use key=\"value\" output format\n", out);
+	fputs(" -J, --json              use JSON output format\n", out);
+	fputs(" -r, --raw               use raw output format\n", out);
+	fputs(" -S, --range-start <n>   first line to print\n", out);
+	fputs(" -E, --range-end <n>     last line to print\n", out);
 
 	exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 }
@@ -156,7 +158,8 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 int main(int argc, char *argv[])
 {
 	struct libscols_table *tb;
-	int c, notree = 0;
+	int c, notree = 0, nstart = -1, nend = -1;
+
 
 	static const struct option longopts[] = {
 		{ "ascii",	0, 0, 'i' },
@@ -166,7 +169,8 @@ int main(int argc, char *argv[])
 		{ "pairs",      0, 0, 'p' },
 		{ "json",       0, 0, 'J' },
 		{ "raw",        0, 0, 'r' },
-
+		{ "range-start",1, 0, 'S' },
+		{ "range-end",  1, 0, 'E' },
 		{ NULL, 0, 0, 0 },
 	};
 
@@ -178,7 +182,7 @@ int main(int argc, char *argv[])
 	if (!tb)
 		err(EXIT_FAILURE, "faild to create output table");
 
-	while((c = getopt_long(argc, argv, "ciJlnpr", longopts, NULL)) != -1) {
+	while((c = getopt_long(argc, argv, "ciJlnprS:E:", longopts, NULL)) != -1) {
 		switch(c) {
 		case 'c':
 			scols_table_set_column_separator(tb, ",");
@@ -206,6 +210,12 @@ int main(int argc, char *argv[])
 			scols_table_enable_raw(tb, 1);
 			notree = 1;
 			break;
+		case 'S':
+			nstart = strtos32_or_err(optarg, "failed to parse range start") - 1;
+			break;
+		case 'E':
+			nend = strtos32_or_err(optarg, "failed to parse range end") - 1;
+			break;
 		default:
 			usage(stderr);
 		}
@@ -219,8 +229,21 @@ int main(int argc, char *argv[])
 	else while (optind < argc)
 		add_lines(tb, argv[optind++]);
 
-	scols_print_table(tb);
-	scols_unref_table(tb);
+	if (nstart >= 0 || nend >= 0) {
+		/* print subset */
+		struct libscols_line *start = NULL, *end = NULL;
+
+		if (nstart >= 0)
+			start = scols_table_get_line(tb, nstart);
+		if (nend >= 0)
+			end = scols_table_get_line(tb, nend);
 
+		if (start || end)
+			scols_table_print_range(tb, start, end);
+	} else
+		/* print all table */
+		scols_print_table(tb);
+
+	scols_unref_table(tb);
 	return EXIT_SUCCESS;
 }
diff --git a/libsmartcols/src/libsmartcols.h.in b/libsmartcols/src/libsmartcols.h.in
index 213d50af2..5f87d965f 100644
--- a/libsmartcols/src/libsmartcols.h.in
+++ b/libsmartcols/src/libsmartcols.h.in
@@ -246,6 +246,10 @@ extern int scols_sort_table(struct libscols_table *tb, struct libscols_column *c
 extern int scols_print_table(struct libscols_table *tb);
 extern int scols_print_table_to_string(struct libscols_table *tb, char **data);
 
+extern int scols_table_print_range(	struct libscols_table *tb,
+					struct libscols_line *start,
+					struct libscols_line *end);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libsmartcols/src/libsmartcols.sym b/libsmartcols/src/libsmartcols.sym
index 1a5505c47..250c06d6d 100644
--- a/libsmartcols/src/libsmartcols.sym
+++ b/libsmartcols/src/libsmartcols.sym
@@ -132,4 +132,5 @@ global:
 	scols_table_get_title;
 	scols_cell_get_flags;
 	scols_cell_set_flags;
+	scols_table_print_range;
 } SMARTCOLS_2.27;
diff --git a/libsmartcols/src/table.c b/libsmartcols/src/table.c
index f91526bbd..fdbc7cd3f 100644
--- a/libsmartcols/src/table.c
+++ b/libsmartcols/src/table.c
@@ -572,13 +572,7 @@ err:
  * @tb: table
  * @n: column number (0..N)
  *
- * This is a shortcut for
- *
- *   ln = scols_new_line();
- *   scols_line_set_....(cl, ...);
- *   scols_table_add_line(tb, ln);
- *
- * Returns: a newly allocate line
+ * Returns: a line or NULL
  */
 struct libscols_line *scols_table_get_line(struct libscols_table *tb,
 					   size_t n)
diff --git a/libsmartcols/src/table_print.c b/libsmartcols/src/table_print.c
index 06fcabe9f..d8965726e 100644
--- a/libsmartcols/src/table_print.c
+++ b/libsmartcols/src/table_print.c
@@ -801,24 +801,39 @@ static int print_header(struct libscols_table *tb, struct libscols_buffer *buf)
 	return rc;
 }
 
-static int print_table(struct libscols_table *tb, struct libscols_buffer *buf)
+static int print_range(	struct libscols_table *tb,
+			struct libscols_buffer *buf,
+			struct libscols_iter *itr,
+			struct libscols_line *end)
 {
 	int rc = 0;
 	struct libscols_line *ln;
-	struct libscols_iter itr;
 
 	assert(tb);
 
-	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
-	while (rc == 0 && scols_table_next_line(tb, &itr, &ln) == 0) {
+	while (rc == 0 && scols_table_next_line(tb, itr, &ln) == 0) {
+
 		fput_line_open(tb);
 		rc = print_line(tb, ln, buf);
-		fput_line_close(tb, scols_iter_is_last(&itr));
+		fput_line_close(tb, scols_iter_is_last(itr));
+
+		if (end && ln == end)
+			break;
 	}
 
 	return rc;
+
 }
 
+static int print_table(struct libscols_table *tb, struct libscols_buffer *buf)
+{
+	struct libscols_iter itr;
+
+	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
+	return print_range(tb, buf, &itr, NULL);
+}
+
+
 static int print_tree_line(struct libscols_table *tb,
 			   struct libscols_line *ln,
 			   struct libscols_buffer *buf,
@@ -1202,33 +1217,14 @@ static size_t strlen_line(struct libscols_line *ln)
 	return sz;
 }
 
-
-
-/**
- * scols_print_table:
- * @tb: table
- *
- * Prints the table to the output stream.
- *
- * Returns: 0, a negative value in case of an error.
- */
-int scols_print_table(struct libscols_table *tb)
+static int initialize_printting(struct libscols_table *tb, struct libscols_buffer **buf)
 {
-	int rc = 0;
 	size_t bufsz, extra_bufsz = 0;
 	struct libscols_line *ln;
 	struct libscols_iter itr;
-	struct libscols_buffer *buf;
-
-	if (!tb)
-		return -EINVAL;
-
-	DBG(TAB, ul_debugobj(tb, "printing"));
+	int rc;
 
-	if (list_empty(&tb->tb_lines)) {
-		DBG(TAB, ul_debugobj(tb, "ignore -- epmty table"));
-		return 0;
-	}
+	DBG(TAB, ul_debugobj(tb, "initialize printting"));
 
 	if (!tb->symbols)
 		scols_table_set_symbols(tb, NULL);	/* use default */
@@ -1262,7 +1258,9 @@ int scols_print_table(struct libscols_table *tb)
 	case SCOLS_FMT_EXPORT:
 	{
 		struct libscols_column *cl;
+
 		scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
+
 		while (rc == 0 && scols_table_next_column(tb, &itr, &cl) == 0) {
 			if (scols_column_is_hidden(cl))
 				continue;
@@ -1275,7 +1273,6 @@ int scols_print_table(struct libscols_table *tb)
 		break;
 	}
 
-
 	/*
 	 * Enlarge buffer if necessary, the buffer should be large enough to
 	 * store line data and tree ascii art (or another decoration).
@@ -1287,16 +1284,87 @@ int scols_print_table(struct libscols_table *tb)
 			bufsz = sz;
 	}
 
-	buf = new_buffer(bufsz + 1);	/* data + space for \0 */
-	if (!buf)
+	*buf = new_buffer(bufsz + 1);	/* data + space for \0 */
+	if (!*buf)
 		return -ENOMEM;
 
 	if (tb->format == SCOLS_FMT_HUMAN) {
-		rc = recount_widths(tb, buf);
+		rc = recount_widths(tb, *buf);
 		if (rc != 0)
-			goto done;
+			goto err;
 	}
 
+	return 0;
+err:
+	free_buffer(*buf);
+	return rc;
+}
+
+/**
+ * scola_table_print_range:
+ * @tb: table
+ * @start: first printed line or NULL to print from the beggin of the table
+ * @end: last printed line or NULL to print all from start.
+ *
+ * Returns: 0, a negative value in case of an error.
+ */
+int scols_table_print_range(	struct libscols_table *tb,
+				struct libscols_line *start,
+				struct libscols_line *end)
+{
+	struct libscols_buffer *buf;
+	struct libscols_iter itr;
+	int rc;
+
+	if (scols_table_is_tree(tb))
+		return -EINVAL;
+
+	DBG(TAB, ul_debugobj(tb, "printing range"));
+
+	rc = initialize_printting(tb, &buf);
+	if (rc)
+		return rc;
+
+	if (start) {
+		itr.direction = SCOLS_ITER_FORWARD;
+		itr.head = &tb->tb_lines;
+		itr.p = &start->ln_lines;
+	} else
+		scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
+
+	rc = print_range(tb, buf, &itr, end);
+
+	free_buffer(buf);
+	return 0;
+}
+
+/**
+ * scols_print_table:
+ * @tb: table
+ *
+ * Prints the table to the output stream.
+ *
+ * Returns: 0, a negative value in case of an error.
+ */
+int scols_print_table(struct libscols_table *tb)
+{
+	int rc = 0;
+	struct libscols_buffer *buf;
+
+	if (!tb)
+		return -EINVAL;
+
+	DBG(TAB, ul_debugobj(tb, "printing"));
+
+	if (list_empty(&tb->tb_lines)) {
+		DBG(TAB, ul_debugobj(tb, "ignore -- epmty table"));
+		return 0;
+	}
+
+	rc = initialize_printting(tb, &buf);
+	if (rc)
+		return rc;
+
 	fput_table_open(tb);
 
 	if (tb->format == SCOLS_FMT_HUMAN)