Introduce enum comphelper::Hash::IterCount instead of bool

Clarifies intention, and with IterCount::NONE prepared to handle
something like old PBKDF1, if anything actually used that. See
https://tools.ietf.org/html/rfc8018#section-5.1 where iteration
count is not part of the re-hash.

Change-Id: I5f97ca7a91f611eced8ced0a0c64961c04535d36

2 files changed, 34 insertions, 17 deletions

diff --git a/include/comphelper/docpasswordhelper.hxx b/include/comphelper/docpasswordhelper.hxx
index 30243c347884..e37a6c71de22 100644
--- a/include/comphelper/docpasswordhelper.hxx
+++ b/include/comphelper/docpasswordhelper.hxx
@@ -24,6 +24,7 @@
 #include <comphelper/comphelperdllapi.h>
 #include <vector>
 #include <comphelper/docpasswordrequest.hxx>
+#include <comphelper/hash.hxx>
 
 namespace com { namespace sun { namespace star { namespace task { class XInteractionHandler; } } } }
 namespace com { namespace sun { namespace star { namespace beans { struct PropertyValue; } } } }
@@ -194,12 +195,14 @@ public:
         @param  nSpinCount
                 If >0 the number of repeated iterations.
 
-        @param  bPrependNotAppend
-                If <FALSE/>, append spin count in iterations as per
+        @param  eIterCount
+                If Hash::IterCount::APPEND, append iteration count as per
                 https://msdn.microsoft.com/en-us/library/dd920692
-                If <TRUE/>, prepend spin count in iterations as per
+                If Hash::IterCount::PREPEND, prepend iteration count as per
                 https://msdn.microsoft.com/en-us/library/dd924776 and
                 https://msdn.microsoft.com/en-us/library/dd925430
+                If Hash::IterCount::NONE, do not add the iteration count to hash
+                iterations.
 
         @param  rAlgorithmName
                 One of "SHA-512", "SHA-256", ... as listed for AlgorithmName in
@@ -216,7 +219,7 @@ public:
             const rtl::OUString& rPassword,
             const rtl::OUString& rSaltValue,
             sal_uInt32 nSpinCount,
-            bool bPrependNotAppend,
+            comphelper::Hash::IterCount eIterCount,
             const rtl::OUString& rAlgorithmName);
 
 
@@ -234,12 +237,14 @@ public:
         @param  nSpinCount
                 If >0 the number of repeated iterations.
 
-        @param  bPrependNotAppend
-                If <FALSE/>, append spin count in iterations as per
+        @param  eIterCount
+                If Hash::IterCount::APPEND, append iteration count as per
                 https://msdn.microsoft.com/en-us/library/dd920692
-                If <TRUE/>, prepend spin count in iterations as per
+                If Hash::IterCount::PREPEND, prepend iteration count as per
                 https://msdn.microsoft.com/en-us/library/dd924776 and
                 https://msdn.microsoft.com/en-us/library/dd925430
+                If Hash::IterCount::NONE, do not add the iteration count to hash
+                iterations.
 
         @param  rAlgorithmName
                 One of "SHA-512", "SHA-256", ... as listed for AlgorithmName in
@@ -257,7 +262,7 @@ public:
             const rtl::OUString& rPassword,
             const rtl::OUString& rSaltValue,
             sal_uInt32 nSpinCount,
-            bool bPrependNotAppend,
+            comphelper::Hash::IterCount eIterCount,
             const rtl::OUString& rAlgorithmName);
 
 
diff --git a/include/comphelper/hash.hxx b/include/comphelper/hash.hxx
index 08ae5fd119a8..52ad5e5cdf1e 100644
--- a/include/comphelper/hash.hxx
+++ b/include/comphelper/hash.hxx
@@ -38,6 +38,13 @@ private:
 
 public:
 
+    enum class IterCount
+    {
+        NONE,       /// Iteration count not added to hash iterations.
+        PREPEND,    /// Iteration count prepended to hash iterations.
+        APPEND      /// Iteration count appended to hash iterations.
+    };
+
     Hash(HashType eType);
     ~Hash();
 
@@ -50,10 +57,6 @@ public:
     /** Calculate hash value with salt (pSalt,nSaltLen) prepended to password
         (pInput,nLength) and repeated iterations run if nSpinCount>0.
 
-        For repeated iterations, each iteration's result plus a 4 byte value
-        (0-based, little endian) containing the number of the iteration
-        appended to the hash value is the input for the next iteration.
-
         This implements the algorithms as specified in
         https://msdn.microsoft.com/en-us/library/dd920692 or
         https://msdn.microsoft.com/en-us/library/dd924776 and
@@ -62,12 +65,21 @@ public:
         @param  pSalt
                 may be nullptr thus no salt prepended
 
-        @param  bPrependNotAppend
-                If <FALSE/>, append spin count in iterations as per
+        @param  nSpinCount
+                If >0, repeat nSpinCount iterations. For each iteration, the
+                previous iteration's result plus a 4 byte value (0-based,
+                little endian) containing the number of the iteration prepended
+                or appended to the hash value is the input for the next
+                iteration.
+
+        @param  eIterCount
+                If IterCount::APPEND, append iteration count as per
                 https://msdn.microsoft.com/en-us/library/dd920692
-                If <TRUE/>, prepend spin count in iterations as per
+                If IterCount::PREPEND, prepend iteration count as per
                 https://msdn.microsoft.com/en-us/library/dd924776 and
                 https://msdn.microsoft.com/en-us/library/dd925430
+                If IterCount::NONE, do not add the iteration count to hash
+                iterations.
 
         @return the raw hash value
      */
@@ -75,7 +87,7 @@ public:
             const unsigned char* pInput, size_t nLength,
             const unsigned char* pSalt, size_t nSaltLen,
             sal_uInt32 nSpinCount,
-            bool bPrependNotAppend,
+            IterCount eIterCount,
             HashType eType);
 
     /** Convenience function to calculate a salted hash with iterations.
@@ -90,7 +102,7 @@ public:
             const rtl::OUString& rPassword,
             const std::vector<unsigned char>& rSaltValue,
             sal_uInt32 nSpinCount,
-            bool bPrependNotAppend,
+            IterCount eIterCount,
             HashType eType);
 
     size_t getLength() const;