Fix search resume after lookup failure

Author: m-o-e

src/rucksack.cr

@@ -20,10 +20,10 @@ class Rucksack
   def self.offset
     return @@offset unless @@offset == 0
 
-    buf = Bytes.new((KNAUTSCHZONE.size).to_i)
     file = ::File.new(Process.executable_path.not_nil!)
 
     loop do
+      buf = Bytes.new((KNAUTSCHZONE.size).to_i)
       begin
         loop do
           bytes_read = file.read(buf)

test/test.sh

@@ -15,7 +15,7 @@ err() {
   cat $to
   echo "-- stderr --"
   cat $te
-  echo "-- stderr --"
+  echo "--"
   echo "ERROR: ${0}:${1} ${ERR}"
   exit 1
 }
@@ -60,5 +60,56 @@ RUCKSACK_MODE=1 $tb >$to 2>$te
 RUCKSACK_MODE=2 $tb >$to 2>$te
 .
 
+### crystal build with phony padding
+
+#### case A: extra nulls before Knautschzone
+crystal build test/test.cr -o ${tb}
+head -c 17042 /dev/zero >>${tb}
+cat .rucksack >>$tb
+RUCKSACK_MODE=0 $tb >$to 2>$te
+.
+RUCKSACK_MODE=1 $tb >$to 2>$te
+.
+RUCKSACK_MODE=2 $tb >$to 2>$te
+.
+
+#### case B: duplicate padding
+
+crystal build test/test.cr -o ${tb}
+head -c 16397 /dev/zero >>${tb}
+cat .rucksack >>$tb
+RUCKSACK_MODE=0 $tb >$to 2>$te
+.
+RUCKSACK_MODE=1 $tb >$to 2>$te
+.
+RUCKSACK_MODE=2 $tb >$to 2>$te
+.
+
+#### case C: extra nulls and truncated header
+
+crystal build test/test.cr -o ${tb}
+head -c 16397 /dev/zero >>${tb}
+echo = >>${tb}
+cat .rucksack >>$tb
+RUCKSACK_MODE=0 $tb >$to 2>$te
+.
+RUCKSACK_MODE=1 $tb >$to 2>$te
+.
+RUCKSACK_MODE=2 $tb >$to 2>$te
+.
+
+#### case D: extra nulls and longer truncated header
+
+crystal build test/test.cr -o ${tb}
+head -c 16397 /dev/zero >>${tb}
+echo ==RUCK >>${tb}
+cat .rucksack >>$tb
+RUCKSACK_MODE=0 $tb >$to 2>$te
+.
+RUCKSACK_MODE=1 $tb >$to 2>$te
+.
+RUCKSACK_MODE=2 $tb >$to 2>$te
+.
+
 echo