From 7301bf89bb4b72ed34b4e27474a6e10705b3b059 Mon Sep 17 00:00:00 2001
From: Veloman Yunkan <veloman.yunkan@gmail.com>
Date: Tue, 26 May 2020 01:50:29 +0400
Subject: [PATCH] Some refactoring of byte-range parsing

---
 src/server/byte_range.cpp | 52 ++++++++++++++++++++++-----------------
 src/server/byte_range.h   |  2 +-
 2 files changed, 31 insertions(+), 23 deletions(-)

diff --git a/src/server/byte_range.cpp b/src/server/byte_range.cpp
index dd21da8a6..45f10b668 100644
--- a/src/server/byte_range.cpp
+++ b/src/server/byte_range.cpp
@@ -24,6 +24,32 @@
 
 namespace kiwix {
 
+namespace {
+
+ByteRange parseByteRange(const std::string& rangeStr)
+{
+  std::istringstream iss(rangeStr);
+
+  int64_t start, end = INT64_MAX;
+  if (iss >> start) {
+    if ( start < 0 ) {
+      if ( iss.eof() )
+        return ByteRange(ByteRange::PARSED, start, end);
+    } else {
+      char c;
+      if (iss >> c && c=='-') {
+        iss >> end; // if this fails, end is not modified, which is OK
+        if (iss.eof() && start <= end)
+          return ByteRange(ByteRange::PARSED, start, end);
+      }
+    }
+  }
+
+  return ByteRange(ByteRange::INVALID, 0, INT64_MAX);
+}
+
+} // unnamed namespace
+
 ByteRange::ByteRange()
   : kind_(NONE)
   , first_(0)
@@ -36,31 +62,13 @@ ByteRange::ByteRange(Kind kind, int64_t first, int64_t last)
   , last_(last)
 {}
 
-ByteRange ByteRange::parse(std::string rangeStr)
+ByteRange ByteRange::parse(const std::string& rangeStr)
 {
-  ByteRange byteRange(INVALID, 0, INT64_MAX);
   const std::string byteUnitSpec("bytes=");
-  if ( kiwix::startsWith(rangeStr, byteUnitSpec) ) {
-    rangeStr.erase(0, byteUnitSpec.size());
-    std::istringstream iss(rangeStr);
+  if ( ! kiwix::startsWith(rangeStr, byteUnitSpec) )
+    return ByteRange(INVALID, 0, INT64_MAX);
 
-    int64_t start, end = INT64_MAX;
-    if (iss >> start) {
-      if ( start < 0 ) {
-        if ( iss.eof() )
-          byteRange = ByteRange(PARSED, start, end);
-      } else {
-        char c;
-        if (iss >> c && c=='-') {
-          iss >> end; // if this fails, end is not modified, which is OK
-          if (iss.eof() && start <= end)
-            byteRange = ByteRange(PARSED, start, end);
-        }
-      }
-    }
-  }
-
-  return byteRange;
+  return parseByteRange(rangeStr.substr(byteUnitSpec.size()));
 }
 
 ByteRange ByteRange::resolve(int64_t contentSize) const
diff --git a/src/server/byte_range.h b/src/server/byte_range.h
index e302cece4..848fd8082 100644
--- a/src/server/byte_range.h
+++ b/src/server/byte_range.h
@@ -57,7 +57,7 @@ class ByteRange
     int64_t last() const { return last_; }
     int64_t length() const { return last_ + 1 - first_; }
 
-    static ByteRange parse(std::string rangeStr);
+    static ByteRange parse(const std::string& rangeStr);
     ByteRange resolve(int64_t contentSize) const;
 
   private: // data