big buffer/buffer_view rework

A buffer is only the text and the corresponding operation. A buffer view
holds information about scroll, dot and mark positions. One way to think
about it is that a buffer is stateless whereas a buffer view is stateful.

1 files changed, 68 insertions, 0 deletions

diff --git a/src/dged/location.c b/src/dged/location.c
new file mode 100644
index 0000000..cac0333
--- /dev/null
+++ b/src/dged/location.c
@@ -0,0 +1,68 @@
+#include "location.h"
+
+bool location_is_between(struct location location, struct location start,
+                         struct location end) {
+  if (location.line >= start.line && location.line <= end.line) {
+    if (location.line == end.line && location.col <= end.col &&
+        location.line == start.line && location.col >= start.col) {
+      // only one line
+      return true;
+    } else if (location.line == start.line && location.line != end.line &&
+               location.col >= start.col) {
+      // we are on the first line
+      return true;
+    } else if (location.line == end.line && location.line != start.line &&
+               location.col <= end.col) {
+      // we are on the last line
+      return true;
+    } else if (location.line != end.line && location.line != start.line) {
+      // we are on lines in between
+      return true;
+    }
+  }
+  return false;
+}
+
+int location_compare(struct location l1, struct location l2) {
+  if (l1.line < l2.line) {
+    return -1;
+  } else if (l1.line > l2.line) {
+    return 1;
+  } else {
+    if (l1.col < l2.col) {
+      return -1;
+    } else if (l1.col > l2.col) {
+      return 1;
+    } else {
+      return 0;
+    }
+  }
+}
+
+struct region region_new(struct location begin, struct location end) {
+  struct region reg = {.begin = begin, .end = end};
+
+  if (end.line < begin.line ||
+      (end.line == begin.line && end.col < begin.col)) {
+    reg.begin = end;
+    reg.end = begin;
+  }
+
+  return reg;
+}
+
+bool region_has_size(struct region region) {
+  return region.end.line != region.begin.line ||
+         (region.end.line == region.begin.line &&
+          region.begin.col != region.end.col);
+}
+
+bool region_is_inside(struct region region, struct location location) {
+  return location_is_between(location, region.begin, region.end);
+}
+
+bool region_is_inside_rect(struct region region, struct location location) {
+  return location.line >= region.begin.line &&
+         location.line <= region.end.line && location.col >= region.begin.col &&
+         location.col <= region.end.col;
+}