Store the size of strings in the cache

By storing the size of the string in the cache, we can make use of
it when comparing the names in the hashtable in pkgCache::FindGrp.

diff --git a/apt-pkg/contrib/mmap.cc b/apt-pkg/contrib/mmap.cc
index 4dc851c1bee7aa23bf2cf31ecb5749c83a98e3d3..74870b404b3f3a9f1d23e72d99002bb84b16ba9b 100644 (file)
--- a/apt-pkg/contrib/mmap.cc
+++ b/apt-pkg/contrib/mmap.cc
@@ -411,7 +411,7 @@ unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
                                                                        /*}}}*/
 // DynamicMMap::WriteString - Write a string to the file               /*{{{*/
 // ---------------------------------------------------------------------
-/* Strings are not aligned to anything */
+/* Strings are aligned to 16 bytes */
 unsigned long DynamicMMap::WriteString(const char *String,
                                       unsigned long Len)
 {
@@ -419,13 +419,20 @@ unsigned long DynamicMMap::WriteString(const char *String,
       Len = strlen(String);
 
    _error->PushToStack();
-   unsigned long const Result = RawAllocate(Len+1,0);
+   unsigned long Result = RawAllocate(Len+1+sizeof(uint16_t),sizeof(uint16_t));
    bool const newError = _error->PendingError();
    _error->MergeWithStack();
 
    if (Base == NULL || (Result == 0 && newError))
       return 0;
 
+   if (Len >= std::numeric_limits<uint16_t>::max())
+      abort();
+
+   uint16_t LenToWrite = Len;
+   memcpy((char *)Base + Result, &LenToWrite, sizeof(LenToWrite));
+   Result += + sizeof(LenToWrite);
+
    memcpy((char *)Base + Result,String,Len);
    ((char *)Base)[Result + Len] = 0;
    return Result;

diff --git a/apt-pkg/pkgcache.cc b/apt-pkg/pkgcache.cc
index f4fb073f5c52b50a086ec5c4e699a809eff419ff..d2ecb8b1f394d14f5a44ddd6569a536b95b7cfff 100644 (file)
--- a/apt-pkg/pkgcache.cc
+++ b/apt-pkg/pkgcache.cc
@@ -59,7 +59,7 @@ pkgCache::Header::Header()
    /* Whenever the structures change the major version should be bumped,
       whenever the generator changes the minor version should be bumped. */
    APT_HEADER_SET(MajorVersion, 10);
-   APT_HEADER_SET(MinorVersion, 3);
+   APT_HEADER_SET(MinorVersion, 4);
    APT_HEADER_SET(Dirty, false);
 
    APT_HEADER_SET(HeaderSz, sizeof(pkgCache::Header));
@@ -307,7 +307,7 @@ pkgCache::GrpIterator pkgCache::FindGrp(StringView Name) {
        // Look at the hash bucket for the group
        Group *Grp = GrpP + HeaderP->GrpHashTableP()[sHash(Name)];
        for (; Grp != GrpP; Grp = GrpP + Grp->Next) {
-               int const cmp = Name.compare(StrP + Grp->Name);
+               int const cmp = Name.compare(ViewString(Grp->Name));
                if (cmp == 0)
                        return GrpIterator(*this, Grp);
                else if (cmp < 0)
@@ -389,7 +389,7 @@ pkgCache::PkgIterator pkgCache::GrpIterator::FindPkg(StringView Arch) const {
        // Iterate over the list to find the matching arch
        for (pkgCache::Package *Pkg = PackageList(); Pkg != Owner->PkgP;
             Pkg = Owner->PkgP + Pkg->NextPackage) {
-               if (Arch.compare(Owner->StrP + Pkg->Arch) == 0)
+               if (Arch == Owner->ViewString(Pkg->Arch))
                        return PkgIterator(*Owner, Pkg);
                if ((Owner->PkgP + S->LastPackage) == Pkg)
                        break;

diff --git a/apt-pkg/pkgcache.h b/apt-pkg/pkgcache.h
index 9fea44e06192f91066d892759bc1e826aefaa8bc..91228f7133ac4196571e97ee690c568b57b92dd1 100644 (file)
--- a/apt-pkg/pkgcache.h
+++ b/apt-pkg/pkgcache.h
@@ -245,6 +245,16 @@ class pkgCache                                                             /*{{{*/
    APT_HIDDEN PkgIterator FindPkg(APT::StringView Name, APT::StringView Arch);
 #endif
 
+#ifdef APT_PKG_EXPOSE_STRING_VIEW
+   APT::StringView ViewString(map_stringitem_t idx) const
+   {
+      char *name = StrP + idx;
+      uint16_t len = *reinterpret_cast<const uint16_t*>(name - sizeof(uint16_t));
+      return APT::StringView(name, len);
+   }
+#endif
+
+
    GrpIterator FindGrp(const std::string &Name);
    PkgIterator FindPkg(const std::string &Name);
    PkgIterator FindPkg(const std::string &Name, const std::string &Arch);

diff --git a/apt-pkg/pkgcachegen.cc b/apt-pkg/pkgcachegen.cc
index 80392ff4543fb10e6548fbac816703aa3ebd0faa..a26237296045d9eb4ca97f485f0e680d0a8cde87 100644 (file)
--- a/apt-pkg/pkgcachegen.cc
+++ b/apt-pkg/pkgcachegen.cc
@@ -518,7 +518,8 @@ bool pkgCacheGenerator::NewGroup(pkgCache::GrpIterator &Grp, StringView Name)
    // Insert it into the hash table
    unsigned long const Hash = Cache.Hash(Name);
    map_pointer_t *insertAt = &Cache.HeaderP->GrpHashTableP()[Hash];
-   while (*insertAt != 0 && Name.compare(Cache.StrP + (Cache.GrpP + *insertAt)->Name) > 0)
+
+   while (*insertAt != 0 && Name.compare(Cache.ViewString((Cache.GrpP + *insertAt)->Name)) > 0)
       insertAt = &(Cache.GrpP + *insertAt)->Next;
    Grp->Next = *insertAt;
    *insertAt = Group;