Add Buffer::Iterator functions to move forward/backward on/up to characters in a line

src/core/Buffer-Iterator.cc

@@ -202,6 +202,80 @@ void Buffer::Iterator::warp_to_offset(size_t offset)
     }
 }
 
+bool Buffer::Iterator::go_forward_in_line_up_to_char(uint32_t c)
+{
+    size_t last_offset = m_offset;
+    Buffer::Iterator it = *this;
+    while (it.go_right_in_line(false))
+    {
+        if (*it == c)
+        {
+            if (last_offset != m_offset)
+            {
+                m_offset = last_offset;
+                return true;
+            }
+            else
+            {
+                return false;
+            }
+        }
+        last_offset = it.m_offset;
+    }
+    return false;
+}
+
+bool Buffer::Iterator::go_forward_in_line_on_to_char(uint32_t c)
+{
+    Buffer::Iterator it = *this;
+    while (it.go_right_in_line(false))
+    {
+        if (*it == c)
+        {
+            m_offset = it.m_offset;
+            return true;
+        }
+    }
+    return false;
+}
+
+bool Buffer::Iterator::go_backward_in_line_up_to_char(uint32_t c)
+{
+    size_t last_offset = m_offset;
+    Buffer::Iterator it = *this;
+    while (it.go_left_in_line())
+    {
+        if (*it == c)
+        {
+            if (last_offset != m_offset)
+            {
+                m_offset = last_offset;
+                return true;
+            }
+            else
+            {
+                return false;
+            }
+        }
+        last_offset = it.m_offset;
+    }
+    return false;
+}
+
+bool Buffer::Iterator::go_backward_in_line_on_to_char(uint32_t c)
+{
+    Buffer::Iterator it = *this;
+    while (it.go_left_in_line())
+    {
+        if (*it == c)
+        {
+            m_offset = it.m_offset;
+            return true;
+        }
+    }
+    return false;
+}
+
 Buffer::Iterator Buffer::Iterator::prev()
 {
     Iterator i = *this;

src/core/Buffer.h

@@ -49,6 +49,10 @@ public:
         bool go_right_in_line(bool allow_eol);
         bool go_previous_line();
         bool go_next_line();
+        bool go_forward_in_line_up_to_char(uint32_t c);
+        bool go_forward_in_line_on_to_char(uint32_t c);
+        bool go_backward_in_line_up_to_char(uint32_t c);
+        bool go_backward_in_line_on_to_char(uint32_t c);
         Iterator prev();
         Iterator next();
         void warp(ssize_t offset_offset, ssize_t line_offset)

test/src/test_Buffer.cc

@@ -109,6 +109,41 @@ TEST(BufferTest, allows_navigating_using_iterators2)
     EXPECT_EQ(C('a'), **iterator);
 }
 
+TEST(BufferTest, allows_navigating_using_iterators3)
+{
+    std::string s("abcabc\n");
+    Buffer b((const uint8_t *)&s[0], s.size());
+    auto it = b.add_cursor();
+
+    EXPECT_FALSE(it->go_forward_in_line_up_to_char(C('d')));
+    EXPECT_EQ(0u, it->offset());
+    EXPECT_FALSE(it->go_forward_in_line_up_to_char(C('b')));
+    EXPECT_EQ(0u, it->offset());
+    EXPECT_TRUE(it->go_forward_in_line_up_to_char(C('c')));
+    EXPECT_EQ(1u, it->offset());
+
+    EXPECT_TRUE(it->go_forward_in_line_on_to_char(C('c')));
+    EXPECT_EQ(2u, it->offset());
+    EXPECT_TRUE(it->go_forward_in_line_on_to_char(C('c')));
+    EXPECT_EQ(5u, it->offset());
+    EXPECT_FALSE(it->go_forward_in_line_on_to_char(C('c')));
+    EXPECT_EQ(5u, it->offset());
+
+    EXPECT_FALSE(it->go_backward_in_line_up_to_char(C('d')));
+    EXPECT_EQ(5u, it->offset());
+    EXPECT_FALSE(it->go_backward_in_line_up_to_char(C('b')));
+    EXPECT_EQ(5u, it->offset());
+    EXPECT_TRUE(it->go_backward_in_line_up_to_char(C('a')));
+    EXPECT_EQ(4u, it->offset());
+
+    EXPECT_FALSE(it->go_backward_in_line_on_to_char(C('d')));
+    EXPECT_EQ(4u, it->offset());
+    EXPECT_TRUE(it->go_backward_in_line_on_to_char(C('a')));
+    EXPECT_EQ(3u, it->offset());
+    EXPECT_TRUE(it->go_backward_in_line_on_to_char(C('a')));
+    EXPECT_EQ(0u, it->offset());
+}
+
 TEST(BufferTest, allows_inserting_and_erasing_characters)
 {
     std::string s("abc\ndef\nghi\n");