3 files changed, 52 insertions, 41 deletions
diff --git a/src/libstore/db.cc b/src/libstore/db.cc
index d2a0026384b0..8c0678d0e88b 100644
--- a/src/libstore/db.cc
+++ b/src/libstore/db.cc
@@ -337,32 +337,9 @@ bool Database::queryStrings(const Transaction & txn, TableId table,
     const string & key, Strings & data)
 {
     string d;
-
     if (!queryString(txn, table, key, d))
         return false;
-
-    string::iterator it = d.begin();
-    
-    while (it != d.end()) {
-
-        if (it + 4 > d.end())
-            throw Error(format("short db entry: `%1%'") % d);
-        
-        unsigned int len;
-        len = (unsigned char) *it++;
-        len |= ((unsigned char) *it++) << 8;
-        len |= ((unsigned char) *it++) << 16;
-        len |= ((unsigned char) *it++) << 24;
-        
-        if (it + len > d.end())
-            throw Error(format("short db entry: `%1%'") % d);
-
-        string s;
-        while (len--) s += *it++;
-
-        data.push_back(s);
-    }
-
+    data = unpackStrings(d);
     return true;
 }
 
@@ -383,23 +360,7 @@ void Database::setString(const Transaction & txn, TableId table,
 void Database::setStrings(const Transaction & txn, TableId table,
     const string & key, const Strings & data)
 {
-    string d;
-    
-    for (Strings::const_iterator it = data.begin();
-         it != data.end(); it++)
-    {
-        string s = *it;
-        unsigned int len = s.size();
-
-        d += len & 0xff;
-        d += (len >> 8) & 0xff;
-        d += (len >> 16) & 0xff;
-        d += (len >> 24) & 0xff;
-        
-        d += s;
-    }
-
-    setString(txn, table, key, d);
+    setString(txn, table, key, packStrings(data));
 }
 
 
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 676404ecfca6..2cfada35450a 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -446,3 +446,48 @@ void _interrupted()
         throw Error("interrupted by the user");
     }
 }
+
+
+string packStrings(const Strings & strings)
+{
+    string d;
+    for (Strings::const_iterator i = strings.begin();
+         i != strings.end(); ++i)
+    {
+        unsigned int len = i->size();
+        d += len & 0xff;
+        d += (len >> 8) & 0xff;
+        d += (len >> 16) & 0xff;
+        d += (len >> 24) & 0xff;
+        d += *i;
+    }
+    return d;
+}
+
+    
+Strings unpackStrings(const string & s)
+{
+    Strings strings;
+    
+    string::const_iterator i = s.begin();
+    
+    while (i != s.end()) {
+
+        if (i + 4 > s.end())
+            throw Error(format("short db entry: `%1%'") % s);
+        
+        unsigned int len;
+        len = (unsigned char) *i++;
+        len |= ((unsigned char) *i++) << 8;
+        len |= ((unsigned char) *i++) << 16;
+        len |= ((unsigned char) *i++) << 24;
+        
+        if (i + len > s.end())
+            throw Error(format("short db entry: `%1%'") % s);
+
+        strings.push_back(string(i, i + len));
+        i += len;
+    }
+    
+    return strings;
+}
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index dcd0bf766cc7..e808f4e1b50b 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -216,4 +216,9 @@ void inline checkInterrupt()
 }
 
 
+/* String packing / unpacking. */
+string packStrings(const Strings & strings);
+Strings unpackStrings(const string & s);
+
+
 #endif /* !__UTIL_H */