src/IO/LineSplitter.cpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #include "LineSplitter.hpp"
  25
  26 #include <string.h>
  27
  28 static std::pair<unsigned, unsigned>
  29 extract_line(const char *data, unsigned length)
  30 {
  31   const char *eol = (const char *)memchr(data, '\n', length);
  32   if (eol == NULL)
  33     return std::pair<unsigned, unsigned>(length, length);
  34
  35   length = eol + 1 - data;
  36
  37   /* purge trailing carriage return characters */
  38   while (eol > data && eol[-1] == '\r')
  39     --eol;
  40
  41   return std::pair<unsigned, unsigned>(eol - data, length);
  42 }
  43
  44 char *
  45 LineSplitter::ReadLine()
  46 {
  47   /* is there enough data left in the buffer to read another line? */
  48   if (memchr(remaining.data, '\n', remaining.length) == NULL) {
  49     /* no: read more data from the Source */
  50     remaining = source.Read();
  51     if (remaining.IsEmpty())
  52       /* end of file */
  53       return NULL;
  54   }
  55
  56   assert(!remaining.IsEmpty());
  57
  58   Source<char>::Range range = remaining;
  59   std::pair<unsigned, unsigned> bounds =
  60     extract_line(range.data, range.length);
  61   source.Consume(bounds.second);
  62   remaining.data += bounds.second;
  63   remaining.length -= bounds.second;
  64
  65   if (bounds.first >= range.length) {
  66     /* last line, not terminated by a line feed: copy to local buffer,
  67        because we want to append the null byte */
  68     char *line = last.get(range.length + 1);
  69     if (line == NULL)
  70       /* allocation has failed */
  71       return NULL;
  72
  73     memcpy(line, range.data, range.length);
  74     line[range.length] = 0;
  75     return line;
  76   } else {
  77     /* there is space left for the null byte */
  78     range.data[bounds.first] = 0;
  79     return range.data;
  80   }
  81 }
  82
  83 long
  84 LineSplitter::GetSize() const
  85 {
  86   return source.GetSize();
  87 }
  88
  89 long
  90 LineSplitter::Tell() const
  91 {
  92   return source.Tell();
  93 }