Replace ZCodec::mbInit with sane enum

...and document how the member functions are supposed to be called from client
code.

Change-Id: Ia4847945e4a361c43a0ed001e3e78e901c9abcad

include/tools/zcodec.hxx

@@ -27,10 +27,16 @@
 
 class SvStream;
 
+// The overall client call protocol is one of:
+// * BeginCompression, Compress, EndCompression
+// * BeginCompression, Decompress, EndCompression
+// * BeginCompression, Write*, EndCompression
+// * BeginCompression, Read*, EndCompression
+// * BeginCompression, ReadAsynchron*, EndCompression
 class TOOLS_DLLPUBLIC ZCodec
 {
-private:
+    enum State { STATE_INIT, STATE_DECOMPRESS, STATE_COMPRESS };
-    sal_uIntPtr     mbInit;
+    State           meState;
     bool            mbStatus;
     bool            mbFinish;
     SvStream*       mpIStm;

tools/source/zcodec/zcodec.cxx

@@ -38,7 +38,7 @@
 static const int gz_magic[2] = { 0x1f, 0x8b }; /* gzip magic header */
 
 ZCodec::ZCodec( sal_uIntPtr nInBufSize, sal_uIntPtr nOutBufSize )
-    : mbInit(0)
+    : meState(STATE_INIT)
     , mbStatus(false)
     , mbFinish(false)
     , mpIStm(NULL)
@@ -63,7 +63,7 @@ ZCodec::~ZCodec()
 
 void ZCodec::BeginCompression( int nCompressLevel, bool updateCrc, bool gzLib )
 {
-    mbInit = 0;
+    assert(meState == STATE_INIT);
     mbStatus = true;
     mbFinish = false;
     mpIStm = mpOStm = NULL;
@@ -83,9 +83,9 @@ long ZCodec::EndCompression()
 {
     long retvalue = 0;
 
-    if ( mbInit != 0 )
+    if (meState != STATE_INIT)
     {
-        if ( mbInit & 2 )   // 1->decompress, 3->compress
+        if (meState == STATE_COMPRESS)
         {
             do
             {
@@ -105,6 +105,7 @@ long ZCodec::EndCompression()
         }
         delete[] mpOutBuf;
         delete[] mpInBuf;
+        meState = STATE_INIT;
     }
     return ( mbStatus ) ? retvalue : -1;
 }
@@ -113,13 +114,11 @@ long ZCodec::Compress( SvStream& rIStm, SvStream& rOStm )
 {
     long nOldTotal_In = PZSTREAM->total_in;
 
-    if ( mbInit == 0 )
+    assert(meState == STATE_INIT);
-    {
     mpIStm = &rIStm;
     mpOStm = &rOStm;
     ImplInitBuf( false );
     mpInBuf = new sal_uInt8[ mnInBufSize ];
-    }
     while (( PZSTREAM->avail_in = mpIStm->Read( PZSTREAM->next_in = mpInBuf, mnInBufSize )) != 0 )
     {
         if ( PZSTREAM->avail_out == 0 )
@@ -139,16 +138,11 @@ long ZCodec::Decompress( SvStream& rIStm, SvStream& rOStm )
     sal_uIntPtr nInToRead;
     long    nOldTotal_Out = PZSTREAM->total_out;
 
-    if ( mbFinish )
+    assert(meState == STATE_INIT);
-        return PZSTREAM->total_out - nOldTotal_Out;
-
-    if ( mbInit == 0 )
-    {
     mpIStm = &rIStm;
     mpOStm = &rOStm;
     ImplInitBuf( true );
     PZSTREAM->next_out = mpOutBuf = new sal_uInt8[ PZSTREAM->avail_out = mnOutBufSize ];
-    }
     do
     {
         if ( PZSTREAM->avail_out == 0 ) ImplWriteBack();
@@ -173,14 +167,12 @@ long ZCodec::Decompress( SvStream& rIStm, SvStream& rOStm )
     while ( ( err != Z_STREAM_END)  && ( PZSTREAM->avail_in || mnInToRead ) );
     ImplWriteBack();
 
-    if ( err == Z_STREAM_END )
-        mbFinish = true;
     return ( mbStatus ) ? (long)(PZSTREAM->total_out - nOldTotal_Out) : -1;
 }
 
 long ZCodec::Write( SvStream& rOStm, const sal_uInt8* pData, sal_uIntPtr nSize )
 {
-    if ( mbInit == 0 )
+    if (meState == STATE_INIT)
     {
         mpOStm = &rOStm;
         ImplInitBuf( false );
@@ -212,7 +204,7 @@ long ZCodec::Read( SvStream& rIStm, sal_uInt8* pData, sal_uIntPtr nSize )
         return 0;           // PZSTREAM->total_out;
 
     mpIStm = &rIStm;
-    if ( mbInit == 0 )
+    if (meState == STATE_INIT)
     {
         ImplInitBuf( true );
     }
@@ -256,7 +248,7 @@ long ZCodec::ReadAsynchron( SvStream& rIStm, sal_uInt8* pData, sal_uIntPtr nSize
     if ( mbFinish )
         return 0;           // PZSTREAM->total_out;
 
-    if ( mbInit == 0 )
+    if (meState == STATE_INIT)
     {
         mpIStm = &rIStm;
         ImplInitBuf( true );
@@ -308,7 +300,7 @@ void ZCodec::ImplWriteBack()
 
     if ( nAvail )
     {
-        if ( mbInit & 2 && mbUpdateCrc )
+        if (meState == STATE_COMPRESS && mbUpdateCrc)
             UpdateCRC( mpOutBuf, nAvail );
         mpOStm->Write( PZSTREAM->next_out = mpOutBuf, nAvail );
         PZSTREAM->avail_out = mnOutBufSize;
@@ -337,11 +329,10 @@ sal_uIntPtr ZCodec::GetCRC()
 
 void ZCodec::ImplInitBuf ( bool nIOFlag )
 {
-    if ( mbInit == 0 )
+    assert(meState == STATE_INIT);
-    {
     if ( nIOFlag )
     {
-            mbInit = 1;
+        meState = STATE_DECOMPRESS;
         if ( mbStatus &&  mbGzLib )
         {
             sal_uInt8 n1, n2, j, nMethod, nFlags;
@@ -397,7 +388,7 @@ void ZCodec::ImplInitBuf ( bool nIOFlag )
     }
     else
     {
-            mbInit = 3;
+        meState = STATE_COMPRESS;
 
         mbStatus = ( deflateInit2_( PZSTREAM, mnCompressLevel, Z_DEFLATED,
             MAX_WBITS, MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY,
@@ -406,7 +397,6 @@ void ZCodec::ImplInitBuf ( bool nIOFlag )
         PZSTREAM->next_out = mpOutBuf = new sal_uInt8[ PZSTREAM->avail_out = mnOutBufSize ];
     }
 }
-}
 
 void ZCodec::UpdateCRC ( sal_uInt8* pSource, long nDatSize)
 {