From ac10575b5f2e9657bb9ba24bf45579cdc5803a94 Mon Sep 17 00:00:00 2001
From: Alek Mosingiewicz <almos666@gmail.com>
Date: Thu, 24 May 2018 21:38:47 +0200
Subject: [PATCH] Read the stream byte by byte, condition for size when
 skipping BOM.

---
 .../chaiscript/language/chaiscript_engine.hpp | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/chaiscript/language/chaiscript_engine.hpp b/include/chaiscript/language/chaiscript_engine.hpp
index a8f35007..1c2d22e6 100644
--- a/include/chaiscript/language/chaiscript_engine.hpp
+++ b/include/chaiscript/language/chaiscript_engine.hpp
@@ -207,15 +207,18 @@ namespace chaiscript
     /// Skip BOM at the beginning of file
     static bool skip_bom(std::ifstream &infile) {
         size_t bytes_needed = 3;
-        std::vector<char> v(bytes_needed);
+        size_t bytes_read = 0;
+        char buffer[256];
 
-        infile.read(&v[0], static_cast<std::streamsize>(bytes_needed));
-        std::string buffer_string(v.begin(), v.end());
+        while (bytes_read < bytes_needed) {
+            infile >> buffer;
+            bytes_read++;
+        }
 
-        if (!infile.eof()
-            && (buffer_string[0] == '\xef')
-            && (buffer_string[1] == '\xbb')
-            && (buffer_string[2] == '\xbf')) {
+        if (bytes_needed == bytes_read
+            && (buffer[0] == '\xef')
+            && (buffer[1] == '\xbb')
+            && (buffer[2] == '\xbf')) {
 
             infile.seekg(3);
             return true;
@@ -239,7 +242,7 @@ namespace chaiscript
 
       assert(size >= 0);
 
-      if (skip_bom(infile)) {
+      if (size >= 3 && skip_bom(infile)) {
           size-=3; // decrement the BOM size from file size, otherwise we'll get parsing errors
           assert(size >=0 ); //and check if there's more text
       }