apt: funcs called with a string literal consisting of a single character

Benchmark:
- https://stackoverflow.com/questions/62058906/why-my-performance-benchmark-gives-me-wrong-results

References:
- https://clang.llvm.org/extra/clang-tidy/checks/performance/prefer-single-char-overloads.html

14 files changed, 28 insertions, 28 deletions

diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
index 8bd77c052..21ed7b242 100644
--- a/apt-pkg/acquire-item.cc
+++ b/apt-pkg/acquire-item.cc
@@ -477,7 +477,7 @@ bool pkgAcqTransactionItem::QueueURI(pkgAcquire::ItemDesc &Item)
 	 if (unlikely(TargetHash == nullptr))
 	    return false;
 	 ::URI uri{U};
-	 auto const trailing_slash = uri.Path.find_last_of("/");
+	 auto const trailing_slash = uri.Path.find_last_of('/');
 	 if (unlikely(trailing_slash == std::string::npos))
 	    return false;
 	 auto altPath = uri.Path.substr(0, trailing_slash) + "/by-hash/" + TargetHash->HashType() + "/" + TargetHash->HashValue();
@@ -495,8 +495,8 @@ bool pkgAcqTransactionItem::QueueURI(pkgAcquire::ItemDesc &Item)
    if (SameMirrorURI.empty() == false)
    {
       UsedMirror = TransactionManager->UsedMirror;
-      if (Item.Description.find(" ") != string::npos)
-	 Item.Description.replace(0, Item.Description.find(" "), UsedMirror);
+      if (Item.Description.find(' ') != string::npos)
+	 Item.Description.replace(0, Item.Description.find(' '), UsedMirror);
    }
    return pkgAcquire::Item::QueueURI(Item);
 }
diff --git a/apt-pkg/acquire-worker.cc b/apt-pkg/acquire-worker.cc
index 55897945c..d712f3e30 100644
--- a/apt-pkg/acquire-worker.cc
+++ b/apt-pkg/acquire-worker.cc
@@ -231,7 +231,7 @@ static void APT_NONNULL(3) ChangeSiteIsMirrorChange(std::string const &NewURI, p
    if (URI::SiteOnly(NewURI) == URI::SiteOnly(desc.URI))
       return;
 
-   auto const firstSpace = desc.Description.find(" ");
+   auto const firstSpace = desc.Description.find(' ');
    if (firstSpace != std::string::npos)
    {
       std::string const OldSite = desc.Description.substr(0, firstSpace);
@@ -277,8 +277,8 @@ bool pkgAcquire::Worker::RunMessages()
 	    for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
 	       (*O)->UsedMirror = UsedMirror;
 
-	    if (Itm->Description.find(" ") != string::npos)
-	       Itm->Description.replace(0, Itm->Description.find(" "), UsedMirror);
+	    if (Itm->Description.find(' ') != string::npos)
+	       Itm->Description.replace(0, Itm->Description.find(' '), UsedMirror);
 	 }
       }
 
diff --git a/apt-pkg/aptconfiguration.cc b/apt-pkg/aptconfiguration.cc
index a0164c6c3..fb6bcdb6d 100644
--- a/apt-pkg/aptconfiguration.cc
+++ b/apt-pkg/aptconfiguration.cc
@@ -175,8 +175,8 @@ std::vector<std::string> const Configuration::getLanguages(bool const &All,
 		builtin.push_back("none");
 		for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) {
 			string const name = SubstVar(Ent->d_name, "%5f", "_");
-			size_t const foundDash = name.rfind("-");
-			size_t const foundUnderscore = name.rfind("_", foundDash);
+			size_t const foundDash = name.rfind('-');
+			size_t const foundUnderscore = name.rfind('_', foundDash);
 			if (foundDash == string::npos || foundUnderscore == string::npos ||
 			    foundDash <= foundUnderscore ||
 			    name.substr(foundUnderscore+1, foundDash-(foundUnderscore+1)) != "Translation")
@@ -692,7 +692,7 @@ std::string Configuration::color(std::string const &colorName, std::string const
    //            | \\x1B<word>       ; color escaped.
    //            | <word>	     ; a simple color name
    //            | <color> <color>   ; a sequence of colors
-   if (color.find(" ") != color.npos)
+   if (color.find(' ') != color.npos)
    {
       std::string res;
       for (auto &&colorPart : VectorizeString(color, ' '))
diff --git a/apt-pkg/cdrom.cc b/apt-pkg/cdrom.cc
index 4da2b738d..6d7613100 100644
--- a/apt-pkg/cdrom.cc
+++ b/apt-pkg/cdrom.cc
@@ -262,7 +262,7 @@ bool pkgCdrom::DropBinaryArch(vector<string> &List)
 
       // Between Start and End is the architecture
       Start += 8;
-      if ((End = strstr(Start,"/")) != 0 && Start != End &&
+      if ((End = strchr(Start,'/')) != 0 && Start != End &&
           APT::Configuration::checkArchitecture(string(Start, End)) == true)
 	 continue; // okay, architecture is accepted
 
diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
index b5200831a..4363ab818 100644
--- a/apt-pkg/contrib/strutl.cc
+++ b/apt-pkg/contrib/strutl.cc
@@ -840,7 +840,7 @@ std::string LookupTag(const std::string &Message, const char *TagC, const char *
       // skip the space leading a multiline (Keep all other whitespaces in the value)
       valuestart = std::next(valuestart);
    }
-   auto const valueend = result.find_last_not_of("\n");
+   auto const valueend = result.find_last_not_of('\n');
    if (valueend == std::string::npos)
       result.clear();
    else
@@ -1506,7 +1506,7 @@ char *safe_snprintf(char *Buffer,char *End,const char *Format,...)
 // ---------------------------------------------------------------------
 string StripEpoch(const string &VerStr)
 {
-   size_t i = VerStr.find(":");
+   size_t i = VerStr.find(':');
    if (i == string::npos)
       return VerStr;
    return VerStr.substr(i+1);
diff --git a/apt-pkg/deb/debmetaindex.cc b/apt-pkg/deb/debmetaindex.cc
index b85163654..8fcb83678 100644
--- a/apt-pkg/deb/debmetaindex.cc
+++ b/apt-pkg/deb/debmetaindex.cc
@@ -1318,7 +1318,7 @@ class APT_HIDDEN debSLTypeDebian : public pkgSourceList::Type		/*{{{*/
    ///        allows you to match a.b.c against itself, .b.c, and .c, but not b.c
    static inline std::string NextLevelDomain(std::string Host)
    {
-      auto nextDot = Host.find(".", 1);
+      auto nextDot = Host.find('.', 1);
       if (nextDot == Host.npos)
 	 return "";
       return Host.substr(nextDot);
diff --git a/apt-pkg/deb/dpkgpm.cc b/apt-pkg/deb/dpkgpm.cc
index 0f2467607..395227f50 100644
--- a/apt-pkg/deb/dpkgpm.cc
+++ b/apt-pkg/deb/dpkgpm.cc
@@ -646,7 +646,7 @@ void pkgDPkgPM::ProcessDpkgStatusLine(char *line)
    }
 
    // At this point we have a pkgname, but it might not be arch-qualified !
-   if (pkgname.find(":") == std::string::npos)
+   if (pkgname.find(':') == std::string::npos)
    {
       pkgCache::GrpIterator const Grp = Cache.FindGrp(pkgname);
       if (unlikely(Grp.end()== true))
@@ -779,7 +779,7 @@ void pkgDPkgPM::ProcessDpkgStatusLine(char *line)
    }
 
    std::string arch = "";
-   if (pkgname.find(":") != string::npos)
+   if (pkgname.find(':') != string::npos)
       arch = StringSplit(pkgname, ":")[1];
    std::string i18n_pkgname = pkgname;
    if (arch.size() != 0)
diff --git a/apt-pkg/indexcopy.cc b/apt-pkg/indexcopy.cc
index 139b10316..089bfd2ce 100644
--- a/apt-pkg/indexcopy.cc
+++ b/apt-pkg/indexcopy.cc
@@ -161,7 +161,7 @@ bool IndexCopy::CopyPackages(string CDROM,string Name,vector<string> &List,
 	       // Attempt to fix busted symlink support for one instance
 	       string OrigFile = File;
 	       string::size_type Start = File.find("binary-");
-	       string::size_type End = File.find("/",Start+3);
+	       string::size_type End = File.find('/',Start+3);
 	       if (Start != string::npos && End != string::npos)
 	       {
 		  File.replace(Start,End-Start,"binary-all");
diff --git a/apt-private/private-install.cc b/apt-private/private-install.cc
index c619aa45a..33c529712 100644
--- a/apt-private/private-install.cc
+++ b/apt-private/private-install.cc
@@ -1114,8 +1114,8 @@ static bool AddIfVolatile(pkgSourceList *const SL, std::vector<PseudoPkg> &Volat
       }
       else
       {
-	 auto const found = pkg.name.rfind("/");
-	 if (found == pkg.name.find("/"))
+	 auto const found = pkg.name.rfind('/');
+	 if (found == pkg.name.find('/'))
 	    _error->Error(_("Unsupported file %s given on commandline"), I);
 	 else
 	 {
diff --git a/apt-private/private-source.cc b/apt-private/private-source.cc
index ebd3a980c..eb7eee931 100644
--- a/apt-private/private-source.cc
+++ b/apt-private/private-source.cc
@@ -86,21 +86,21 @@ static pkgSrcRecords::Parser *FindSrc(const char *Name,
       TmpSrc = TmpSrc.substr(4);
    }
    // extract release
-   size_t found = TmpSrc.find_last_of("/");
+   size_t found = TmpSrc.find_last_of('/');
    if (found != std::string::npos)
    {
       RelTag = TmpSrc.substr(found+1);
       TmpSrc = TmpSrc.substr(0,found);
    }
    // extract the version
-   found = TmpSrc.find_last_of("=");
+   found = TmpSrc.find_last_of('=');
    if (found != std::string::npos)
    {
       VerTag = UserRequestedVerTag = TmpSrc.substr(found+1);
       TmpSrc = TmpSrc.substr(0,found);
    }
    // extract arch
-   found = TmpSrc.find_last_of(":");
+   found = TmpSrc.find_last_of(':');
    if (found != std::string::npos)
    {
       ArchTag = TmpSrc.substr(found+1);
@@ -359,14 +359,14 @@ bool DoSource(CommandLine &CmdL)
       while (pos != std::string::npos)
       {
 	 pos += strlen("\nVcs-");
-	 std::string vcs = srec.substr(pos,srec.find(":",pos)-pos);
+	 std::string vcs = srec.substr(pos,srec.find(':',pos)-pos);
 	 if(vcs == "Browser") 
 	 {
 	    pos = srec.find("\nVcs-", pos);
 	    continue;
 	 }
 	 pos += vcs.length()+2;
-	 std::string::size_type epos = srec.find("\n", pos);
+	 std::string::size_type epos = srec.find('\n', pos);
 	 std::string const uri = srec.substr(pos,epos-pos);
 	 ioprintf(c1out, _("NOTICE: '%s' packaging is maintained in "
 		  "the '%s' version control system at:\n"
@@ -806,7 +806,7 @@ bool DoBuildDep(CommandLine &CmdL)
 	 WriteBuildDependencyPackage(buildDepsPkgFile, pseudo, pseudoArch,
 	       GetBuildDeps(Last, Src.c_str(), hostArch));
 	 std::string reltag = *I;
-	 size_t found = reltag.find_last_of("/");
+	 size_t found = reltag.find_last_of('/');
 	 if (found == std::string::npos)
 	    reltag.clear();
 	 else
diff --git a/cmdline/apt-helper.cc b/cmdline/apt-helper.cc
index 4404259d8..0700de0f6 100644
--- a/cmdline/apt-helper.cc
+++ b/cmdline/apt-helper.cc
@@ -117,7 +117,7 @@ static bool DoSrvLookup(CommandLine &CmdL)				/*{{{*/
       std::vector<SrvRec> srv_records;
       std::string const name = CmdL.FileList[i];
       c0out << "# Target\tPriority\tWeight\tPort # for " << name << std::endl;
-      size_t const found = name.find(":");
+      size_t const found = name.find(':');
       if (found != std::string::npos)
       {
 	 std::string const host = name.substr(0, found);
diff --git a/ftparchive/byhash.cc b/ftparchive/byhash.cc
index b24f6158e..8013bd7a6 100644
--- a/ftparchive/byhash.cc
+++ b/ftparchive/byhash.cc
@@ -50,7 +50,7 @@ void DeleteAllButMostRecent(std::string dir, int KeepFiles)
 std::string GenByHashFilename(std::string ByHashOutputFile, HashString const &h)
 {
    std::string const ByHash = "/by-hash/" + h.HashType() + "/" + h.HashValue();
-   size_t trailing_slash = ByHashOutputFile.find_last_of("/");
+   size_t trailing_slash = ByHashOutputFile.find_last_of('/');
    if (trailing_slash == std::string::npos)
       trailing_slash = 0;
    ByHashOutputFile = ByHashOutputFile.replace(
diff --git a/methods/basehttp.cc b/methods/basehttp.cc
index d335e6fa0..db0ed228f 100644
--- a/methods/basehttp.cc
+++ b/methods/basehttp.cc
@@ -330,7 +330,7 @@ static std::string fixURIEncoding(std::string const &part)
 {
    // if the server sends a space this is not an encoded URI
    // so other clients seem to encode it and we do it as well
-   if (part.find_first_of(" ") != std::string::npos)
+   if (part.find_first_of(' ') != std::string::npos)
       return aptMethod::URIEncode(part);
    return part;
 }
diff --git a/methods/mirror.cc b/methods/mirror.cc
index 6da0b4258..6fbaa40e6 100644
--- a/methods/mirror.cc
+++ b/methods/mirror.cc
@@ -334,7 +334,7 @@ std::string MirrorMethod::GetMirrorFileURI(std::string const &Message, FetchItem
 	 auto const colon = uristr.find(':');
 	 if (unlikely(colon == std::string::npos))
 	    continue;
-	 auto const plus = uristr.find("+");
+	 auto const plus = uristr.find('+');
 	 if (plus < colon)
 	 {
 	    // started as tor+mirror+http we want to get the file via tor+http