text-motion: add functions to iterate over lines of a range

2 files changed, 38 insertions, 0 deletions

diff --git a/text-motions.c b/text-motions.c
index 43077e9..f62ba22 100644
--- a/text-motions.c
+++ b/text-motions.c
@@ -16,6 +16,7 @@
 #include <ctype.h>
 #include <string.h>
 #include "text-motions.h"
+#include "text-util.h"
 #include "util.h"
 
 // TODO: specify this per file type?
@@ -195,6 +196,38 @@ size_t text_line_down(Text *txt, size_t pos) {
 	return text_line_offset(txt, next, pos - bol);
 }
 
+size_t text_range_line_first(Text *txt, Filerange *r) {
+	if (!text_range_valid(r))
+		return EPOS;
+	return r->start;
+}
+
+size_t text_range_line_last(Text *txt, Filerange *r) {
+	if (!text_range_valid(r))
+		return EPOS;
+	size_t pos = text_line_begin(txt, r->end);
+	if (pos == r->end) {
+		/* range ends at a begin of a line, skip last line ending */
+		pos = text_line_prev(txt, pos);
+		pos = text_line_begin(txt, pos);
+	}
+	return r->start <= pos ? pos : r->start;
+}
+
+size_t text_range_line_next(Text *txt, Filerange *r, size_t pos) {
+	if (!text_range_contains(r, pos))
+		return EPOS;
+	size_t newpos = text_line_next(txt, pos);
+	return newpos != pos && newpos < r->end ? newpos : EPOS;
+}
+
+size_t text_range_line_prev(Text *txt, Filerange *r, size_t pos) {
+	if (!text_range_contains(r, pos))
+		return EPOS;
+	size_t newpos = text_line_begin(txt, text_line_prev(txt, pos));
+	return newpos != pos && r->start <= newpos ? newpos : EPOS;
+}
+
 static size_t text_customword_start_next(Text *txt, size_t pos, int (*isboundry)(int)) {
 	char c;
 	Iterator it = text_iterator_get(txt, pos);
diff --git a/text-motions.h b/text-motions.h
index 438a42f..72878cd 100644
--- a/text-motions.h
+++ b/text-motions.h
@@ -42,6 +42,11 @@ size_t text_line_char_prev(Text*, size_t pos);
 /* move to same offset in previous/next line */
 size_t text_line_up(Text*, size_t pos);
 size_t text_line_down(Text*, size_t pos);
+/* functions to iterate over all line beginnings in a given range */
+size_t text_range_line_first(Text*, Filerange*);
+size_t text_range_line_last(Text*, Filerange*);
+size_t text_range_line_next(Text*, Filerange*, size_t pos);
+size_t text_range_line_prev(Text*, Filerange*, size_t pos);
 /*
  * A longword consists of a sequence of non-blank characters, separated with
  * white space. TODO?: An empty line is also considered to be a word.