Adding commands, BeforeEdit AfterEdit

src/text_editor/buffer.cpp

@@ -211,6 +211,8 @@ void MergeSort(int64_t Count, Edit *First, Edit *Temp) {
 void ApplyEdits(Buffer *buffer, Array<Edit> edits) {
     Scratch scratch((Arena *)buffer->allocator.object);
 
+    // Figure out how much we insert and how much we delete so
+    // we can resize buffers properly if necessary
     Assert(edits.len);
     int64_t size_to_delete = 0;
     int64_t size_to_insert = 0;
@@ -241,6 +243,7 @@ void ApplyEdits(Buffer *buffer, Array<Edit> edits) {
     Array<Edit> edits_copy = edits.copy(scratch);
     MergeSort(edits.len, edits_copy.data, edits.data);
 
+    // Try resizing the buffers
     int64_t len_offset              = size_to_insert - size_to_delete;
     int64_t allocated_size_required = Max((int64_t)0, len_offset);
     if (buffer->len + allocated_size_required > buffer->cap) {
@@ -257,6 +260,7 @@ void ApplyEdits(Buffer *buffer, Array<Edit> edits) {
         buffer->cap = new_cap;
     }
 
+    // Figure out what we need to write to the second buffer
     int srci = buffer->bi;
     int dsti = (buffer->bi + 1) % 2;
 
@@ -293,12 +297,14 @@ void ApplyEdits(Buffer *buffer, Array<Edit> edits) {
         writes.add({dest_range, source_string});
     }
 
+    // Make sure there are no gaps between ranges
 #if DEBUG_BUILD
     for (int64_t i = 0; i < writes.len - 1; i += 1) {
         Assert(writes[i].range.max == writes[i + 1].range.min);
     }
 #endif
 
+    // Write to the second buffer
     int64_t new_buffer_len = 0;
     For(writes) {
         Assert(it.range.min >= 0);