made wxTextFile work in Unicode; also made it possible to use it with non seekable files

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@38399 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/textfile.cpp

@@ -88,39 +88,52 @@ bool wxTextFile::OnClose()
 bool wxTextFile::OnRead(wxMBConv& conv)
 {
     // file should be opened and we must be in it's beginning
-    wxASSERT( m_file.IsOpened() && m_file.Tell() == 0 );
+    wxASSERT( m_file.IsOpened() &&
+                (m_file.GetKind() != wxFILE_KIND_DISK || m_file.Tell() == 0) );
 
-    char *strBuf, *strPtr, *strEnd;
-    char ch, chLast = '\0';
-    char buf[1024];
-    size_t nRead;
+    char buf[1025];
+    wxChar chLast = '\0';
+    wxString str;
 
-    strPtr = strBuf = new char[1024];
-    strEnd = strBuf + 1024;
-
-    do
+    for ( ;; )
     {
-        nRead = m_file.Read(buf, WXSIZEOF(buf));
-        if ( nRead == (size_t)wxInvalidOffset )
+        // leave space for trailing NUL
+        ssize_t nRead = m_file.Read(buf, WXSIZEOF(buf) - 1);
+
+        if ( nRead == wxInvalidOffset )
         {
             // read error (error message already given in wxFile::Read)
-            delete[] strBuf;
             return false;
         }
 
-        for (size_t n = 0; n < nRead; n++)
+        if ( nRead == 0 )
+            break;
+
+        buf[nRead] = '\0';
+
+        // append to the remains of the last block, don't overwrite
+        str += wxString(buf, conv);
+
+        // the beginning of the current line, changes inside the loop
+        const wxChar *lineStart = str.begin();
+        const wxChar * const end = str.end();
+        for ( const wxChar *p = lineStart; p != end; p++ )
         {
-            ch = buf[n];
+            const wxChar ch = *p;
             switch ( ch )
             {
                 case '\n':
-                    // Dos/Unix line termination
-                    *strPtr = '\0';
-                    AddLine(wxString(strBuf, conv),
-                            chLast == '\r' ? wxTextFileType_Dos
-                                           : wxTextFileType_Unix);
-                    strPtr = strBuf;
-                    chLast = '\n';
+                    // could be a DOS or Unix EOL
+                    if ( chLast == '\r' )
+                    {
+                        AddLine(wxString(lineStart, p - 1), wxTextFileType_Dos);
+                    }
+                    else // bare '\n', Unix style
+                    {
+                        AddLine(wxString(lineStart, p), wxTextFileType_Unix);
+                    }
+
+                    lineStart = p + 1;
                     break;
 
                 case '\r':
@@ -128,50 +141,34 @@ bool wxTextFile::OnRead(wxMBConv& conv)
                     {
                         // Mac empty line
                         AddLine(wxEmptyString, wxTextFileType_Mac);
+                        lineStart = p + 1;
                     }
-                    else
-                        chLast = '\r';
+                    //else: we don't what this is yet -- could be a Mac EOL or
+                    //      start of DOS EOL so wait for next char
                     break;
 
                 default:
                     if ( chLast == '\r' )
                     {
                         // Mac line termination
-                        *strPtr = '\0';
-                        AddLine(wxString(strBuf, conv), wxTextFileType_Mac);
-                        chLast = ch;
-                        strPtr = strBuf;
-                        *(strPtr++) = ch;
-                    }
-                    else
-                    {
-                        // add to the current line
-                        *(strPtr++) = ch;
-                        if ( strPtr == strEnd )
-                        {
-                            // we must allocate more memory
-                            size_t size = strEnd - strBuf;
-                            char *newBuf = new char[size + 1024];
-                            memcpy(newBuf, strBuf, size);
-                            delete[] strBuf;
-                            strBuf = newBuf;
-                            strEnd = strBuf + size + 1024;
-                            strPtr = strBuf + size;
-                        }
+                        AddLine(wxString(lineStart, p - 1), wxTextFileType_Mac);
+                        lineStart = p;
                     }
             }
-        }
-    } while ( nRead == WXSIZEOF(buf) );
 
-    // anything in the last line?
-    if ( strPtr != strBuf )
-    {
-        *strPtr = '\0';
-        AddLine(wxString(strBuf, conv),
-                wxTextFileType_None); // no line terminator
+            chLast = ch;
+        }
+
+        // remove the part we already processed
+        str.erase(0, lineStart - str.begin());
+    }
+
+    // anything in the last line?
+    if ( !str.empty() )
+    {
+        AddLine(str, wxTextFileType_None); // no line terminator
     }
 
-    delete[] strBuf;
     return true;
 }