From c3852e950ad12086912df98c7613675aa8bccd98 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Fri, 17 Nov 2017 16:58:00 -0500
Subject: [PATCH] Add Buffer::erase_range()

---
 src/core/Buffer.cc      | 13 +++++++++++++
 src/core/Buffer.h       |  2 ++
 test/src/test_Buffer.cc | 31 +++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/src/core/Buffer.cc b/src/core/Buffer.cc
index 1856f58..d2daa35 100644
--- a/src/core/Buffer.cc
+++ b/src/core/Buffer.cc
@@ -212,6 +212,19 @@ void Buffer::erase_code_point(const Buffer::Iterator & position)
     }
 }
 
+void Buffer::erase_range(const Buffer::Iterator & start,
+        const Buffer::Iterator & end)
+{
+    if (start.valid() && (start < end))
+    {
+        push_operation();
+        size_t start_offset = start.offset();
+        size_t end_offset = end.valid() ? end.offset() : m_gap_buffer->size();
+        erase_data(start_offset, end_offset - start_offset, true);
+        pop_operation();
+    }
+}
+
 void Buffer::erase_data(size_t offset, size_t length, bool do_record_change)
 {
     warp_iterators_before_delete(offset, length);
diff --git a/src/core/Buffer.h b/src/core/Buffer.h
index 11f69b8..b74d484 100644
--- a/src/core/Buffer.h
+++ b/src/core/Buffer.h
@@ -131,6 +131,8 @@ public:
     bool insert_mode() const { return m_insert_mode; }
     void insert_code_point(const Buffer::Iterator & position, uint32_t code_point);
     void erase_code_point(const Buffer::Iterator & position);
+    void erase_range(const Buffer::Iterator & start,
+            const Buffer::Iterator & end);
     std::shared_ptr<std::string> filename() const { return m_filename; }
     Iterator begin() const { return Iterator(this); }
     Iterator end() const { return *m_eof_iterator; }
diff --git a/test/src/test_Buffer.cc b/test/src/test_Buffer.cc
index 76384dc..a59ed5b 100644
--- a/test/src/test_Buffer.cc
+++ b/test/src/test_Buffer.cc
@@ -133,6 +133,37 @@ TEST(BufferTest, allows_inserting_and_erasing_characters)
     b.exit_insert_mode();
 }
 
+TEST(BufferTest, allows_erasing_ranges)
+{
+    std::string s("abc\ndef\n");
+    Buffer b((const uint8_t *)&s[0], s.size());
+    auto it = b.add_iterator();
+    auto it2 = b.add_iterator();
+    it2->go_next_line();
+
+    /* Invalid tests. */
+    b.erase_range(b.end(), b.end());
+    EXPECT_EQ(ss("abc\ndef\n"), b.get_string());
+    b.erase_range(*it, b.begin());
+    EXPECT_EQ(ss("abc\ndef\n"), b.get_string());
+
+    EXPECT_EQ(C('a'), **it);
+    EXPECT_EQ(C('d'), **it2);
+    b.erase_range(*it, *it2);
+    EXPECT_EQ(ss("def\n"), b.get_string());
+    EXPECT_EQ(*it, *it2);
+    EXPECT_EQ(C('d'), **it);
+    while (it2->valid())
+    {
+        it2->go_forward();
+    }
+    EXPECT_EQ(C('d'), **it);
+    b.erase_range(*it, *it2);
+    EXPECT_EQ(ss(""), b.get_string());
+    EXPECT_FALSE(it->valid());
+    EXPECT_FALSE(it2->valid());
+}
+
 TEST(BufferTest, adds_a_newline_after_inserted_character_when_inserting_in_an_empty_buffer)
 {
     Buffer b;