Switch performance critical code to use APT::StringView

This improves performance of the cache generation on my
ARM platform (4x Cortex A15) by about 10% to 20% from
2.35-2.50 to 2.1 seconds.

1 files changed, 6 insertions, 1 deletions

diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
index b9bfc2c98..856e5ee9f 100644
--- a/apt-pkg/contrib/strutl.cc
+++ b/apt-pkg/contrib/strutl.cc
@@ -1114,12 +1114,17 @@ static int HexDigit(int c)
 /* The length of the buffer must be exactly 1/2 the length of the string. */
 bool Hex2Num(const string &Str,unsigned char *Num,unsigned int Length)
 {
+   return Hex2Num(APT::StringView(Str), Num, Length);
+}
+
+bool Hex2Num(const APT::StringView Str,unsigned char *Num,unsigned int Length)
+{
    if (Str.length() != Length*2)
       return false;
    
    // Convert each digit. We store it in the same order as the string
    int J = 0;
-   for (string::const_iterator I = Str.begin(); I != Str.end();J++, I += 2)
+   for (auto I = Str.begin(); I != Str.end();J++, I += 2)
    {
       int first_half = HexDigit(I[0]);
       int second_half;