move much of the buffer layout code from BufferPane to BufferView

test/src/test_BufferView.cc

@@ -0,0 +1,67 @@
+#include "gtest/gtest.h"
+#include "BufferView.h"
+
+static std::shared_ptr<Buffer> buffer1()
+{
+    static const char data[] =
+        "0\n"
+        "1ab\n"
+        "2abc\n"
+        "3\n"
+        "4\n"
+        "5\n"
+        "6abcdefg\n"
+        "7\n"
+        "8\n"
+        "9abcdefghijklmno\n"
+        "10\n"
+        "11\n"
+        "12\n";
+    return std::make_shared<Buffer>((const uint8_t *)data, strlen(data));
+}
+
+class MyCharacterWidthDeterminer : public CharacterWidthDeterminer
+{
+    int operator()(uint32_t character)
+    {
+        if (character < 32)
+        {
+            return 2;
+        }
+        else
+        {
+            return 1;
+        }
+    }
+} Cwd;
+
+static int LineNumber(const Buffer::Iterator & iterator)
+{
+    int line_number = 0;
+    Buffer::Iterator i = iterator;
+    for (;;)
+    {
+        uint32_t c = *i;
+        if ((c < '0') || (c > '9'))
+            break;
+        line_number *= 10;
+        line_number += ((int)c - '0');
+        i.go_forward();
+    }
+    return line_number;
+}
+
+TEST(BufferViewTest, iterates_through_screen_lines_with_no_wrapping)
+{
+    std::shared_ptr<Buffer> b = buffer1();
+    std::shared_ptr<Buffer::Iterator> iterator = b->add_iterator();
+    BufferView bv(b, iterator, Cwd);
+    bv.resize(40, 8);
+    int times_called = 0;
+    bv.iter_lines([&times_called](int row_offset, const Buffer::Iterator & iterator) -> bool {
+            EXPECT_EQ(times_called, LineNumber(iterator));
+            times_called++;
+            return true;
+            });
+    EXPECT_EQ(8, times_called);
+}