1 files changed, 38 insertions, 16 deletions

diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
index 2100ee47b..87f57a30e 100644
--- a/apt-pkg/contrib/strutl.cc
+++ b/apt-pkg/contrib/strutl.cc
@@ -45,14 +45,26 @@ using namespace std;
 // ---------------------------------------------------------------------
 namespace APT {
    namespace String {
-std::string Strip(const std::string &s)
+std::string Strip(const std::string &str)
 {
-   size_t start = s.find_first_not_of(" \t\n");
-   // only whitespace
-   if (start == string::npos)
+   // ensure we have at least one character
+   if (str.empty() == true)
+      return str;
+
+   char const * const s = str.c_str();
+   size_t start = 0;
+   for (; isspace(s[start]) != 0; ++start)
+      ; // find the first not-space
+
+   // string contains only whitespaces
+   if (s[start] == '\0')
       return "";
-   size_t end = s.find_last_not_of(" \t\n");
-   return s.substr(start, end-start+1);
+
+   size_t end = str.length() - 1;
+   for (; isspace(s[end]) != 0; --end)
+      ; // find the last not-space
+
+   return str.substr(start, end - start + 1);
 }
 
 bool Endswith(const std::string &s, const std::string &end)
@@ -434,23 +446,30 @@ string TimeToStr(unsigned long Sec)
 /* This replaces all occurrences of Subst with Contents in Str. */
 string SubstVar(const string &Str,const string &Subst,const string &Contents)
 {
+   if (Subst.empty() == true)
+      return Str;
+
    string::size_type Pos = 0;
    string::size_type OldPos = 0;
    string Temp;
-   
-   while (OldPos < Str.length() && 
+
+   while (OldPos < Str.length() &&
 	  (Pos = Str.find(Subst,OldPos)) != string::npos)
    {
-      Temp += string(Str,OldPos,Pos) + Contents;
-      OldPos = Pos + Subst.length();      
+      if (OldPos != Pos)
+	 Temp.append(Str, OldPos, Pos - OldPos);
+      if (Contents.empty() == false)
+	 Temp.append(Contents);
+      OldPos = Pos + Subst.length();
    }
-   
+
    if (OldPos == 0)
       return Str;
-   
+
+   if (OldPos >= Str.length())
+      return Temp;
    return Temp + string(Str,OldPos);
 }
-
 string SubstVar(string Str,const struct SubstVar *Vars)
 {
    for (; Vars->Subst != 0; Vars++)
@@ -697,9 +716,12 @@ string LookupTag(const string &Message,const char *Tag,const char *Default)
    then returns the result. Several varients on true/false are checked. */
 int StringToBool(const string &Text,int Default)
 {
-   char *End;
-   int Res = strtol(Text.c_str(),&End,0);   
-   if (End != Text.c_str() && Res >= 0 && Res <= 1)
+   char *ParseEnd;
+   int Res = strtol(Text.c_str(),&ParseEnd,0);
+   // ensure that the entire string was converted by strtol to avoid
+   // failures on "apt-cache show -a 0ad" where the "0" is converted
+   const char *TextEnd = Text.c_str()+Text.size();
+   if (ParseEnd == TextEnd && Res >= 0 && Res <= 1)
       return Res;
    
    // Check for positives