[PATCH 1/3] speed up debVersioningSystem::DoCmpVersion a bit

[Jann Horn <jann@thejh.net>]

---
 apt-pkg/deb/debversion.cc |   37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/apt-pkg/deb/debversion.cc b/apt-pkg/deb/debversion.cc
index 1405612..6b75e66 100644
--- a/apt-pkg/deb/debversion.cc
+++ b/apt-pkg/deb/debversion.cc
@@ -119,6 +119,27 @@ int debVersioningSystem::CmpFragment(const char *A,const char *AEnd,
    // Shouldnt happen
    return 1;
 }
+
+const char *memchr_short(const char *s, int c, const char *e)
+{
+   const char *p = s;
+   while (p != e) {
+      if (*p == c) return p;
+      p++;
+   }
+   return s;
+}
+
+const char *memrchr_short(const char *s, int c, const char *e)
+{
+   const char *p = e;
+   while (p != s) {
+      p--;
+      if (*p == c) return p;
+   }
+   return e;
+}
+
 									/*}}}*/
 // debVS::CmpVersion - Comparison for versions				/*{{{*/
 // ---------------------------------------------------------------------
@@ -128,12 +149,8 @@ int debVersioningSystem::DoCmpVersion(const char *A,const char *AEnd,
 				      const char *B,const char *BEnd)
 {
    // Strip off the epoch and compare it
-   const char *lhs = (const char*) memchr(A, ':', AEnd - A);
-   const char *rhs = (const char*) memchr(B, ':', BEnd - B);
-   if (lhs == NULL)
-      lhs = A;
-   if (rhs == NULL)
-      rhs = B;
+   const char *lhs = (const char*) memchr_short(A, ':', AEnd);
+   const char *rhs = (const char*) memchr_short(B, ':', BEnd);
    
    // Special case: a zero epoch is the same as no epoch,
    // so remove it.
@@ -168,12 +185,8 @@ int debVersioningSystem::DoCmpVersion(const char *A,const char *AEnd,
       rhs++;
    
    // Find the last -
-   const char *dlhs = (const char*) memrchr(lhs, '-', AEnd - lhs);
-   const char *drhs = (const char*) memrchr(rhs, '-', BEnd - rhs);
-   if (dlhs == NULL)
-      dlhs = AEnd;
-   if (drhs == NULL)
-      drhs = BEnd;
+   const char *dlhs = (const char*) memrchr_short(lhs, '-', AEnd);
+   const char *drhs = (const char*) memrchr_short(rhs, '-', BEnd);
    
    // Compare the main version
    Res = CmpFragment(lhs,dlhs,rhs,drhs);
-- 
1.7.10.4