From f6da44fdbb87dc3960a5326f727bf5886dfec7fb Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Tue, 6 Sep 2016 21:33:19 -0700
Subject: [PATCH] Add ts_node_descendant_for_byte_range

---
 include/tree_sitter/runtime.h |  2 ++
 spec/runtime/node_spec.cc     | 20 ++++++++++++++++++--
 src/runtime/node.c            | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/include/tree_sitter/runtime.h b/include/tree_sitter/runtime.h
index 3fed02ce..1b2c90b6 100644
--- a/include/tree_sitter/runtime.h
+++ b/include/tree_sitter/runtime.h
@@ -81,6 +81,8 @@ TSNode ts_node_prev_sibling(TSNode);
 TSNode ts_node_prev_named_sibling(TSNode);
 TSNode ts_node_descendant_for_char_range(TSNode, size_t, size_t);
 TSNode ts_node_named_descendant_for_char_range(TSNode, size_t, size_t);
+TSNode ts_node_descendant_for_byte_range(TSNode, size_t, size_t);
+TSNode ts_node_named_descendant_for_byte_range(TSNode, size_t, size_t);
 TSNode ts_node_descendant_for_point_range(TSNode, TSPoint, TSPoint);
 TSNode ts_node_named_descendant_for_point_range(TSNode, TSPoint, TSPoint);
 
diff --git a/spec/runtime/node_spec.cc b/spec/runtime/node_spec.cc
index 9c7e0e39..33754c2d 100644
--- a/spec/runtime/node_spec.cc
+++ b/spec/runtime/node_spec.cc
@@ -392,7 +392,7 @@ describe("Node", []() {
   });
 
   describe("descendant_for_char_range(start, end)", [&]() {
-    it("returns the smallest concrete node that spans the given range", [&]() {
+    it("returns the smallest node that spans the given range", [&]() {
       TSNode node1 = ts_node_descendant_for_char_range(array_node, colon_index, colon_index);
       AssertThat(ts_node_name(node1, document), Equals(":"));
       AssertThat(ts_node_start_byte(node1), Equals(colon_index));
@@ -409,7 +409,23 @@ describe("Node", []() {
     });
   });
 
-  describe("named_descendant_for_point_range(start, end)", [&]() {
+  describe("descendant_for_byte_range(start, end)", [&]() {
+    it("returns the smallest concrete node that spans the given range", [&]() {
+      ts_document_set_input_string(document, "[\"αβγδ\", \"αβγδ\"]");
+      ts_document_parse(document);
+      TSNode array_node = ts_document_root_node(document);
+
+      TSNode node1 = ts_node_descendant_for_char_range(array_node, 7, 7);
+      AssertThat(ts_node_name(node1, document), Equals(","));
+
+      TSNode node2 = ts_node_descendant_for_byte_range(array_node, 6, 10);
+      AssertThat(ts_node_name(node2, document), Equals("string"));
+      AssertThat(ts_node_start_byte(node2), Equals(1));
+      AssertThat(ts_node_end_byte(node2), Equals(11));
+    });
+  });
+
+  describe("descendant_for_point_range(start, end)", [&]() {
     it("returns the smallest concrete node that spans the given range", [&]() {
       TSNode node1 = ts_node_descendant_for_point_range(array_node, {6, 7}, {6, 7});
       AssertThat(ts_node_name(node1, document), Equals(":"));
diff --git a/src/runtime/node.c b/src/runtime/node.c
index 5fed59dd..e28a646b 100644
--- a/src/runtime/node.c
+++ b/src/runtime/node.c
@@ -169,6 +169,33 @@ static inline TSNode ts_node__descendant_for_char_range(TSNode self, size_t min,
   return last_visible_node;
 }
 
+static inline TSNode ts_node__descendant_for_byte_range(TSNode self, size_t min,
+                                                        size_t max,
+                                                        bool include_anonymous) {
+  TSNode node = self;
+  TSNode last_visible_node = self;
+
+  bool did_descend = true;
+  while (did_descend) {
+    did_descend = false;
+
+    for (size_t i = 0; i < ts_node__tree(node)->child_count; i++) {
+      TSNode child = ts_node__direct_child(node, i);
+      if (ts_node_start_byte(child) > min)
+        break;
+      if (ts_node_end_byte(child) > max) {
+        node = child;
+        if (ts_node__is_relevant(node, include_anonymous))
+          last_visible_node = node;
+        did_descend = true;
+        break;
+      }
+    }
+  }
+
+  return last_visible_node;
+}
+
 static inline TSNode ts_node__descendant_for_point_range(TSNode self,
                                                          TSPoint min,
                                                          TSPoint max,
@@ -330,6 +357,14 @@ TSNode ts_node_named_descendant_for_char_range(TSNode self, size_t min, size_t m
   return ts_node__descendant_for_char_range(self, min, max, false);
 }
 
+TSNode ts_node_descendant_for_byte_range(TSNode self, size_t min, size_t max) {
+  return ts_node__descendant_for_byte_range(self, min, max, true);
+}
+
+TSNode ts_node_named_descendant_for_byte_range(TSNode self, size_t min, size_t max) {
+  return ts_node__descendant_for_byte_range(self, min, max, false);
+}
+
 TSNode ts_node_descendant_for_point_range(TSNode self, TSPoint min, TSPoint max) {
   return ts_node__descendant_for_point_range(self, min, max, true);
 }