Changeset 1813 for trunk/gsdl/lib

Timestamp:

2000-12-19T16:54:36+13:00 (23 years ago)

Author:

sjboddie

Message:

Fixed a bug in the file_tail function. I'm still not sure it was an
actual bug but it sure made weird things happen on Windows 95

File:

• trunk/gsdl/lib/fileutil.cpp (modified) (4 diffs)

trunk/gsdl/lib/fileutil.cpp

@@ -212 +212 @@
   // freeing this memory can cause a runtime error on some (particularly
   // debug) versions of VC++
-  delete dirpath;
+  //  delete dirpath;
   
   if (hSearch == INVALID_HANDLE_VALUE) {
@@ -335 +335 @@
 }
 
-
+// This is a fairly quick and nasty attempt at doing a "tail" on
+// a file (i.e. returning the last numlines lines of filename).
+// It has one important limitation in that it expects lines to be 
+// 256 characters long on average.
+// This of course makes it possible that it won't return numlines
+// lines if there are some very long lines.
+// It also makes it fairly inefficient as it always reads in 
+// numlines*256 characters which is much more than generally 
+// necessary.
+// For current needs it's fine though.
 text_t file_tail (const text_t &filename, int numlines) {
+
   if (numlines < 1) numlines = 1;
-  int numchars = 256*numlines;
+  streampos numchars = 256*numlines;
 
   text_tarray lines;
@@ -348 +358 @@
   delete filenamec;
   if (file_in) {
-
-    // this should be here to keep things reasonably fast
-    // when there's a long file to tail but I can't work out 
-    // how to tell when it's rewound past the beginning of the file 
-    // (which causes some problems) 
-
-    //    file_in.seekg (-numchars, ios::end);
+    file_in.seekg (0, ios::end);
+    streampos file_length = file_in.tellg();
+    if (file_length < numchars) numchars = file_length;
+    file_in.seekg (-numchars, ios::end);
 
     while (!file_in.eof()) {
@@ -384 +391 @@
 }
 
-// returns the last numlines lines (or last numlines*256 
-// characters) of file
-/*
-text_t file_tail (const text_t &filename) {
-
-
-  text_t return_str, tmpstr;
-  char *filenamec = filename.getcstr();
-  char linec[256];
-
-  ifstream file_in (filenamec);
-  delete filenamec;
-  if (file_in) {
-    file_in.seekg (-256, ios::end);
-    file_in.getline (linec, 256, EOF);
-    file_in.close();
-
-    tmpstr.setcstr (linec);
-    text_t::const_iterator here = tmpstr.begin();
-    text_t::const_iterator end = tmpstr.end();
-    while (here != end) {
-      // handle trailing carriage returns
-      while (*here == '\n') {
-    here++;
-    if (here == end) return return_str;
-    else if (*here != '\n') return_str.clear();
-      } 
-      if (*here == '\\') return_str.push_back ('\\');
-      return_str.push_back (*here);
-      here ++;
-    }
-  }
-  return return_str;
-}
-*/
 #ifdef __WIN32__