From 0efbd65a242a96eca09c22697caa47249806bbe5 Mon Sep 17 00:00:00 2001
From: Corey Johnson <cj@github.com>
Date: Wed, 21 Mar 2012 14:25:28 -0700
Subject: [PATCH] Add Buffer.characterIndexForPosition

---
 spec/atom/buffer-spec.coffee | 8 ++++++++
 src/atom/buffer.coffee       | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/spec/atom/buffer-spec.coffee b/spec/atom/buffer-spec.coffee
index d52d897ba..892507281 100644
--- a/spec/atom/buffer-spec.coffee
+++ b/spec/atom/buffer-spec.coffee
@@ -203,3 +203,11 @@ describe 'Buffer', ->
         lineLength = buffer.lineForRow(2).length
         range = [[2,10], [4,10]]
         expect(buffer.getTextInRange(range)).toBe "ems.length <= 1) return items;\n    var pivot = items.shift(), current, left = [], right = [];\n    while("
+
+  describe ".characterIndexForPosition(position)", ->
+    it "returns the total number of charachters that precede the given position", ->
+      expect(buffer.characterIndexForPosition([0, 0])).toBe 0
+      expect(buffer.characterIndexForPosition([0, 1])).toBe 1
+      expect(buffer.characterIndexForPosition([0, 29])).toBe 29
+      expect(buffer.characterIndexForPosition([1, 0])).toBe 30
+      expect(buffer.characterIndexForPosition([2, 0])).toBe 61
\ No newline at end of file
diff --git a/src/atom/buffer.coffee b/src/atom/buffer.coffee
index 1a477241f..84ed96644 100644
--- a/src/atom/buffer.coffee
+++ b/src/atom/buffer.coffee
@@ -1,5 +1,6 @@
 _ = require 'underscore'
 fs = require 'fs'
+Point = require 'point'
 Range = require 'range'
 EventEmitter = require 'event-emitter'
 UndoManager = require 'undo-manager'
@@ -59,6 +60,13 @@ class Buffer
   lastLine: ->
     @lineForRow(@lastRow())
 
+  characterIndexForPosition: (position) ->
+    position = Point.fromObject(position)
+
+    index = 0
+    index += @getLineLength(row) + 1 for row in [0...position.row]
+    index + position.column
+
   deleteRow: (row) ->
     range = null
     if row == @lastRow()