diff --git a/dlls/msi/msipriv.h b/dlls/msi/msipriv.h
index 73bccecd94f..4757da4d319 100644
--- a/dlls/msi/msipriv.h
+++ b/dlls/msi/msipriv.h
@@ -754,9 +754,9 @@ enum StringPersistence
 };
 
 extern BOOL msi_addstringW( string_table *st, const WCHAR *data, int len, USHORT refcount, enum StringPersistence persistence ) DECLSPEC_HIDDEN;
-extern UINT msi_string2idW( const string_table *st, LPCWSTR buffer, UINT *id ) DECLSPEC_HIDDEN;
+extern UINT msi_string2id( const string_table *st, const WCHAR *data, int len, UINT *id ) DECLSPEC_HIDDEN;
 extern VOID msi_destroy_stringtable( string_table *st ) DECLSPEC_HIDDEN;
-extern const WCHAR *msi_string_lookup_id( const string_table *st, UINT id ) DECLSPEC_HIDDEN;
+extern const WCHAR *msi_string_lookup( const string_table *st, UINT id, int *len ) DECLSPEC_HIDDEN;
 extern HRESULT msi_init_string_table( IStorage *stg ) DECLSPEC_HIDDEN;
 extern string_table *msi_load_string_table( IStorage *stg, UINT *bytes_per_strref ) DECLSPEC_HIDDEN;
 extern UINT msi_save_string_table( const string_table *st, IStorage *storage, UINT *bytes_per_strref ) DECLSPEC_HIDDEN;
diff --git a/dlls/msi/msiquery.c b/dlls/msi/msiquery.c
index 433b3c772f6..4b826f85811 100644
--- a/dlls/msi/msiquery.c
+++ b/dlls/msi/msiquery.c
@@ -347,7 +347,7 @@ UINT msi_view_get_row(MSIDATABASE *db, MSIVIEW *view, UINT row, MSIRECORD **rec)
         {
             LPCWSTR sval;
 
-            sval = msi_string_lookup_id(db->strings, ival);
+            sval = msi_string_lookup(db->strings, ival, NULL);
             MSI_RecordSetStringW(*rec, i, sval);
         }
         else
diff --git a/dlls/msi/storages.c b/dlls/msi/storages.c
index c980df8aa32..35c1de5903d 100644
--- a/dlls/msi/storages.c
+++ b/dlls/msi/storages.c
@@ -312,7 +312,7 @@ static UINT storages_find_row(MSISTORAGESVIEW *sv, MSIRECORD *rec, UINT *row)
     UINT r, i, id, data;
 
     str = MSI_RecordGetString(rec, 1);
-    r = msi_string2idW(sv->db->strings, str, &id);
+    r = msi_string2id(sv->db->strings, str, -1, &id);
     if (r != ERROR_SUCCESS)
         return r;
 
diff --git a/dlls/msi/streams.c b/dlls/msi/streams.c
index 71616e93eb0..d9d632fafbc 100644
--- a/dlls/msi/streams.c
+++ b/dlls/msi/streams.c
@@ -299,7 +299,7 @@ static UINT streams_find_row(MSISTREAMSVIEW *sv, MSIRECORD *rec, UINT *row)
     UINT r, i, id, data;
 
     str = MSI_RecordGetString(rec, 1);
-    r = msi_string2idW(sv->db->strings, str, &id);
+    r = msi_string2id(sv->db->strings, str, -1, &id);
     if (r != ERROR_SUCCESS)
         return r;
 
diff --git a/dlls/msi/string.c b/dlls/msi/string.c
index 065c04a3720..5e2c574d10b 100644
--- a/dlls/msi/string.c
+++ b/dlls/msi/string.c
@@ -45,7 +45,8 @@ struct msistring
 {
     USHORT persistent_refcount;
     USHORT nonpersistent_refcount;
-    LPWSTR str;
+    WCHAR *data;
+    int    len;
 };
 
 struct string_table
@@ -112,7 +113,7 @@ VOID msi_destroy_stringtable( string_table *st )
     {
         if( st->strings[i].persistent_refcount ||
             st->strings[i].nonpersistent_refcount )
-            msi_free( st->strings[i].str );
+            msi_free( st->strings[i].data );
     }
     msi_free( st->strings );
     msi_free( st->sorted );
@@ -162,6 +163,19 @@ static int st_find_free_entry( string_table *st )
     return st->freeslot;
 }
 
+static inline int cmp_string( const WCHAR *str1, int len1, const WCHAR *str2, int len2 )
+{
+    if (len1 < len2) return -1;
+    else if (len1 > len2) return 1;
+    while (len1)
+    {
+        if (*str1 == *str2) { str1++; str2++; }
+        else return *str1 - *str2;
+        len1--;
+    }
+    return 0;
+}
+
 static int find_insert_index( const string_table *st, UINT string_id )
 {
     int i, c, low = 0, high = st->sortcount - 1;
@@ -169,8 +183,8 @@ static int find_insert_index( const string_table *st, UINT string_id )
     while (low <= high)
     {
         i = (low + high) / 2;
-        c = strcmpW( st->strings[string_id].str, st->strings[st->sorted[i]].str );
-
+        c = cmp_string( st->strings[string_id].data, st->strings[string_id].len,
+                        st->strings[st->sorted[i]].data, st->strings[st->sorted[i]].len );
         if (c < 0)
             high = i - 1;
         else if (c > 0)
@@ -194,7 +208,8 @@ static void insert_string_sorted( string_table *st, UINT string_id )
     st->sortcount++;
 }
 
-static void set_st_entry( string_table *st, UINT n, LPWSTR str, USHORT refcount, enum StringPersistence persistence )
+static void set_st_entry( string_table *st, UINT n, WCHAR *str, int len, USHORT refcount,
+                          enum StringPersistence persistence )
 {
     if (persistence == StringPersistent)
     {
@@ -207,7 +222,8 @@ static void set_st_entry( string_table *st, UINT n, LPWSTR str, USHORT refcount,
         st->strings[n].nonpersistent_refcount = refcount;
     }
 
-    st->strings[n].str = str;
+    st->strings[n].data = str;
+    st->strings[n].len  = len;
 
     insert_string_sorted( st, n );
 
@@ -237,9 +253,8 @@ static UINT msi_string2idA( const string_table *st, LPCSTR buffer, UINT *id )
         return ERROR_NOT_ENOUGH_MEMORY;
     MultiByteToWideChar( st->codepage, 0, buffer, -1, str, sz );
 
-    r = msi_string2idW( st, str, id );
+    r = msi_string2id( st, str, sz - 1, id );
     msi_free( str );
-
     return r;
 }
 
@@ -289,7 +304,7 @@ static int msi_addstring( string_table *st, UINT n, const CHAR *data, int len, U
     MultiByteToWideChar( st->codepage, 0, data, len, str, sz );
     str[sz] = 0;
 
-    set_st_entry( st, n, str, refcount, persistence );
+    set_st_entry( st, n, str, sz, refcount, persistence );
 
     return n;
 }
@@ -301,10 +316,10 @@ int msi_addstringW( string_table *st, const WCHAR *data, int len, USHORT refcoun
 
     if( !data )
         return 0;
-    if( !data[0] )
+    if( !data[0] && !len )
         return 0;
 
-    if( msi_string2idW( st, data, &n ) == ERROR_SUCCESS )
+    if (msi_string2id( st, data, len, &n) == ERROR_SUCCESS )
     {
         if (persistence == StringPersistent)
             st->strings[n].persistent_refcount += refcount;
@@ -320,7 +335,7 @@ int msi_addstringW( string_table *st, const WCHAR *data, int len, USHORT refcoun
     /* allocate a new string */
     if(len<0)
         len = strlenW(data);
-    TRACE("%s, n = %d len = %d\n", debugstr_w(data), n, len );
+    TRACE( "%s, n = %d len = %d\n", debugstr_wn(data, len), n, len );
 
     str = msi_alloc( (len+1)*sizeof(WCHAR) );
     if( !str )
@@ -328,13 +343,13 @@ int msi_addstringW( string_table *st, const WCHAR *data, int len, USHORT refcoun
     memcpy( str, data, len*sizeof(WCHAR) );
     str[len] = 0;
 
-    set_st_entry( st, n, str, refcount, persistence );
+    set_st_entry( st, n, str, len, refcount, persistence );
 
     return n;
 }
 
 /* find the string identified by an id - return null if there's none */
-const WCHAR *msi_string_lookup_id( const string_table *st, UINT id )
+const WCHAR *msi_string_lookup( const string_table *st, UINT id, int *len )
 {
     if( id == 0 )
         return szEmpty;
@@ -345,7 +360,9 @@ const WCHAR *msi_string_lookup_id( const string_table *st, UINT id )
     if( id && !st->strings[id].persistent_refcount && !st->strings[id].nonpersistent_refcount)
         return NULL;
 
-    return st->strings[id].str;
+    if (len) *len = st->strings[id].len;
+
+    return st->strings[id].data;
 }
 
 /*
@@ -361,16 +378,15 @@ const WCHAR *msi_string_lookup_id( const string_table *st, UINT id )
  */
 static UINT msi_id2stringA( const string_table *st, UINT id, LPSTR buffer, UINT *sz )
 {
-    UINT len, lenW;
+    int len, lenW;
     const WCHAR *str;
 
     TRACE("Finding string %d of %d\n", id, st->maxcount);
 
-    str = msi_string_lookup_id( st, id );
+    str = msi_string_lookup( st, id, &lenW );
     if( !str )
         return ERROR_FUNCTION_FAILED;
 
-    lenW = strlenW( str );
     len = WideCharToMultiByte( st->codepage, 0, str, lenW, NULL, 0, NULL, NULL );
     if( *sz < len )
     {
@@ -382,20 +398,22 @@ static UINT msi_id2stringA( const string_table *st, UINT id, LPSTR buffer, UINT
 }
 
 /*
- *  msi_string2idW
+ *  msi_string2id
  *
  *  [in] st         - pointer to the string table
  *  [in] str        - string to find in the string table
  *  [out] id        - id of the string, if found
  */
-UINT msi_string2idW( const string_table *st, LPCWSTR str, UINT *id )
+UINT msi_string2id( const string_table *st, const WCHAR *str, int len, UINT *id )
 {
     int i, c, low = 0, high = st->sortcount - 1;
 
+    if (len < 0) len = strlenW( str );
+
     while (low <= high)
     {
         i = (low + high) / 2;
-        c = strcmpW( str, st->strings[st->sorted[i]].str );
+        c = cmp_string( str, len, st->strings[st->sorted[i]].data, st->strings[st->sorted[i]].len );
 
         if (c < 0)
             high = i - 1;
@@ -407,7 +425,6 @@ UINT msi_string2idW( const string_table *st, LPCWSTR str, UINT *id )
             return ERROR_SUCCESS;
         }
     }
-
     return ERROR_INVALID_PARAMETER;
 }
 
@@ -415,7 +432,7 @@ static void string_totalsize( const string_table *st, UINT *datasize, UINT *pool
 {
     UINT i, len, holesize;
 
-    if( st->strings[0].str || st->strings[0].persistent_refcount || st->strings[0].nonpersistent_refcount)
+    if( st->strings[0].data || st->strings[0].persistent_refcount || st->strings[0].nonpersistent_refcount)
         ERR("oops. element 0 has a string\n");
 
     *poolsize = 4;
@@ -425,14 +442,14 @@ static void string_totalsize( const string_table *st, UINT *datasize, UINT *pool
     {
         if( !st->strings[i].persistent_refcount )
         {
-            TRACE("[%u] nonpersistent = %s\n", i, debugstr_w(st->strings[i].str));
+            TRACE("[%u] nonpersistent = %s\n", i, debugstr_wn(st->strings[i].data, st->strings[i].len));
             (*poolsize) += 4;
         }
-        else if( st->strings[i].str )
+        else if( st->strings[i].data )
         {
-            TRACE("[%u] = %s\n", i, debugstr_w(st->strings[i].str));
-            len = WideCharToMultiByte( st->codepage, 0,
-                     st->strings[i].str, -1, NULL, 0, NULL, NULL);
+            TRACE("[%u] = %s\n", i, debugstr_wn(st->strings[i].data, st->strings[i].len));
+            len = WideCharToMultiByte( st->codepage, 0, st->strings[i].data, st->strings[i].len + 1,
+                                       NULL, 0, NULL, NULL);
             if( len )
                 len--;
             (*datasize) += len;
diff --git a/dlls/msi/table.c b/dlls/msi/table.c
index 93b0268c494..3276259b2bf 100644
--- a/dlls/msi/table.c
+++ b/dlls/msi/table.c
@@ -660,7 +660,7 @@ static UINT get_tablecolumns( MSIDATABASE *db, LPCWSTR szTableName, MSICOLUMNINF
     }
 
     /* convert table and column names to IDs from the string table */
-    r = msi_string2idW( db->strings, szTableName, &table_id );
+    r = msi_string2id( db->strings, szTableName, -1, &table_id );
     if (r != ERROR_SUCCESS)
     {
         WARN("Couldn't find id for %s\n", debugstr_w(szTableName));
@@ -693,9 +693,9 @@ static UINT get_tablecolumns( MSIDATABASE *db, LPCWSTR szTableName, MSICOLUMNINF
                 ERR("duplicate column %d\n", col);
                 continue;
             }
-            colinfo[col - 1].tablename = msi_string_lookup_id( db->strings, table_id );
+            colinfo[col - 1].tablename = msi_string_lookup( db->strings, table_id, NULL );
             colinfo[col - 1].number = col;
-            colinfo[col - 1].colname = msi_string_lookup_id( db->strings, id );
+            colinfo[col - 1].colname = msi_string_lookup( db->strings, id, NULL );
             colinfo[col - 1].type = read_table_int( table->data, i, table->colinfo[3].offset,
                                                     sizeof(USHORT) ) - (1 << 15);
             colinfo[col - 1].offset = 0;
@@ -763,9 +763,9 @@ UINT msi_create_table( MSIDATABASE *db, LPCWSTR name, column_info *col_info,
         UINT table_id = msi_addstringW( db->strings, col->table, -1, 1, string_persistence );
         UINT col_id = msi_addstringW( db->strings, col->column, -1, 1, string_persistence );
 
-        table->colinfo[ i ].tablename = msi_string_lookup_id( db->strings, table_id );
+        table->colinfo[ i ].tablename = msi_string_lookup( db->strings, table_id, NULL );
         table->colinfo[ i ].number = i + 1;
-        table->colinfo[ i ].colname = msi_string_lookup_id( db->strings, col_id );
+        table->colinfo[ i ].colname = msi_string_lookup( db->strings, col_id, NULL );
         table->colinfo[ i ].type = col->type;
         table->colinfo[ i ].offset = 0;
         table->colinfo[ i ].ref_count = 0;
@@ -981,7 +981,7 @@ BOOL TABLE_Exists( MSIDATABASE *db, LPCWSTR name )
         !strcmpW( name, szStreams ) || !strcmpW( name, szStorages ) )
         return TRUE;
 
-    r = msi_string2idW( db->strings, name, &table_id );
+    r = msi_string2id( db->strings, name, -1, &table_id );
     if( r != ERROR_SUCCESS )
     {
         TRACE("Couldn't find id for %s\n", debugstr_w(name));
@@ -1087,7 +1087,7 @@ static UINT msi_stream_name( const MSITABLEVIEW *tv, UINT row, LPWSTR *pstname )
 
             if ( tv->columns[i].type & MSITYPE_STRING )
             {
-                sval = msi_string_lookup_id( tv->db->strings, ival );
+                sval = msi_string_lookup( tv->db->strings, ival, NULL );
                 if ( !sval )
                 {
                     r = ERROR_INVALID_PARAMETER;
@@ -1276,7 +1276,7 @@ static UINT get_table_value_from_record( MSITABLEVIEW *tv, MSIRECORD *rec, UINT
         LPCWSTR sval = MSI_RecordGetString( rec, iField );
         if (sval)
         {
-            r = msi_string2idW(tv->db->strings, sval, pvalue);
+            r = msi_string2id(tv->db->strings, sval, -1, pvalue);
             if (r != ERROR_SUCCESS)
                 return ERROR_NOT_FOUND;
         }
@@ -2343,7 +2343,7 @@ static MSIRECORD *msi_get_transform_record( const MSITABLEVIEW *tv, const string
             LPCWSTR sval;
 
             val = read_raw_int(rawdata, ofs, bytes_per_strref);
-            sval = msi_string_lookup_id( st, val );
+            sval = msi_string_lookup( st, val, NULL );
             MSI_RecordSetStringW( rec, i+1, sval );
             TRACE(" field %d [%s]\n", i+1, debugstr_w(sval));
             ofs += bytes_per_strref;
@@ -2395,13 +2395,12 @@ static void dump_record( MSIRECORD *rec )
 
 static void dump_table( const string_table *st, const USHORT *rawdata, UINT rawsize )
 {
-    LPCWSTR sval;
     UINT i;
-
-    for( i=0; i<(rawsize/2); i++ )
+    for (i = 0; i < rawsize / 2; i++)
     {
-        sval = msi_string_lookup_id( st, rawdata[i] );
-        MESSAGE(" %04x %s\n", rawdata[i], debugstr_w(sval) );
+        int len;
+        const WCHAR *sval = msi_string_lookup( st, rawdata[i], &len );
+        MESSAGE(" %04x %s\n", rawdata[i], debugstr_wn(sval, len) );
     }
 }
 
@@ -2425,7 +2424,7 @@ static UINT* msi_record_to_row( const MSITABLEVIEW *tv, MSIRECORD *rec )
             str = MSI_RecordGetString( rec, i+1 );
             if (str)
             {
-                r = msi_string2idW( tv->db->strings, str, &data[i] );
+                r = msi_string2id( tv->db->strings, str, -1, &data[i] );
 
                 /* if there's no matching string in the string table,
                    these keys can't match any record, so fail now. */
diff --git a/dlls/msi/where.c b/dlls/msi/where.c
index 36c8ec83e01..45fda442bc8 100644
--- a/dlls/msi/where.c
+++ b/dlls/msi/where.c
@@ -494,7 +494,7 @@ static UINT STRING_evaluate( MSIWHEREVIEW *wv, const UINT rows[],
     case EXPR_COL_NUMBER_STRING:
         r = expr_fetch_value(&expr->u.column, rows, &val);
         if (r == ERROR_SUCCESS)
-            *str =  msi_string_lookup_id(wv->db->strings, val);
+            *str =  msi_string_lookup(wv->db->strings, val, NULL);
         else
             *str = NULL;
         break;
@@ -883,7 +883,7 @@ static UINT join_find_row( MSIWHEREVIEW *wv, MSIRECORD *rec, UINT *row )
     UINT r, i, id, data;
 
     str = MSI_RecordGetString( rec, 1 );
-    r = msi_string2idW( wv->db->strings, str, &id );
+    r = msi_string2id( wv->db->strings, str, -1, &id );
     if (r != ERROR_SUCCESS)
         return r;