/* Copyright (c) 1997-2006
   Ewgenij Gawrilow, Michael Joswig (Technische Universitaet Berlin, Germany)
   http://www.math.tu-berlin.de/polymake,  mailto:polymake@math.tu-berlin.de

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2, or (at your option) any
   later version: http://www.gnu.org/licenses/gpl.txt.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
*/

#ifndef _POLYMAKE_CHARBUFFER_H
#define _POLYMAKE_CHARBUFFER_H "$Project: polymake $$Id: CharBuffer.h 7461 2006-11-12 23:25:23Z gawrilow $"

#include <sys/types.h>
#include <cctype>
#include <cstring>
#include <socketstream.h>

namespace pm {

class CharBuffer : public std::streambuf_with_input_width {
private:
   // never create
   CharBuffer();
   ~CharBuffer();
public:
   typedef std::streambuf::traits_type traits_type;
   typedef std::streambuf::int_type int_type;

   static void skip_all(std::streambuf *_buf)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      PM_SET_BUF_GET_CUR_END(buf);
   }

   static int seek_forward(std::streambuf *_buf, int offset)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      const int_type eof_char=traits_type::eof();
      if (buf->gptr()+offset >= buf->egptr() && buf->underflow()==eof_char)
	 return eof_char;
      return buf->gptr()[offset];
   }

   static int next_ws(std::streambuf *_buf, int offset=0, bool report_eof=true)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      const int_type eof_char=traits_type::eof();
      for (int_type c; (c=seek_forward(buf, offset))!=eof_char; ++offset)
	 if (isspace(c)) return offset;
      return report_eof ? -1 : offset;
   }

   static int next_non_ws(std::streambuf *_buf, int offset=0)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      const int_type eof_char=traits_type::eof();
      for (int_type c; (c=seek_forward(buf, offset))!=eof_char; ++offset)
	 if (!isspace(c)) return offset;
      return -1;
   }

   static int skip_ws(std::streambuf *_buf)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      int i=next_non_ws(buf);
      if (i<0) {
	 skip_all(buf);
	 return -1;
      } else {
	 buf->gbump(i);
	 return 0;
      }
   }

   static int find_char_forward(std::streambuf *_buf, char c, int offset=0)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      const int_type eof_char=traits_type::eof();
      if (seek_forward(buf, offset) != eof_char) {
	 do {
	    if (char *found=(char*)memchr(buf->gptr()+offset, c, buf->egptr()-(buf->gptr()+offset)))
	       return found-buf->gptr();
	    offset=buf->egptr()-buf->gptr();
	 } while (buf->underflow() != eof_char);
      }
      return -1;
   }

   static int_type ignore(std::streambuf *_buf, char c)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      const int_type eof_char=traits_type::eof();
      int_type next_c;
      while ((next_c=seek_forward(buf,0)) != eof_char) {
	 if (next_c==c) {
	    buf->gbump(1);
	    break;
	 }
	 if (char *found=(char*)memchr(buf->gptr(), c, buf->egptr()-buf->gptr())) {
	    buf->gbump(found-buf->gptr()+1);
	    return c;
	 }
	 PM_SET_BUF_GET_CUR_END(buf);
      }
      return next_c;
   }

   static int find_string_forward(std::streambuf *_buf, const char *c, int len, int offset)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      const int_type eof_char=traits_type::eof();
      while ((offset=find_char_forward(buf, c[0], offset)) >= 0  &&
	     seek_forward(buf, offset+len-1) != eof_char) {
	 if (!memcmp(buf->gptr()+offset, c, len)) return offset;
	 ++offset;
      }
      return -1;
   }

   static int count_char(std::streambuf *_buf, char c)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      char *start=buf->gptr(), *end=buf->egptr();
      int cnt=0;
      while ((start=(char*)memchr(start, c, end-start)) != 0) {
	 ++cnt; ++start;
      }
      return cnt;
   }

   static int count_lines(std::streambuf *buf)
   {
      if (skip_ws(buf)<0) return 0;
      return count_char(buf,'\n');
   }

   static int matching_brace (std::streambuf *buf, char opening, char closing, int offset=0);
   static int get_string(std::streambuf *buf, std::string&, char delim);

   static char* get_ptr(std::streambuf *_buf)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      return buf->gptr();
   }
   static char* end_get_ptr(std::streambuf *_buf)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      return buf->egptr();
   }
   static void get_bump(std::streambuf *_buf, int offset)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      buf->gbump(offset);
   }
   static void set_end_get_ptr(std::streambuf *_buf, char *end)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      PM_SET_BUF_GET_END(buf,end);
   }
   static void set_end_get_ptr(std::streambuf *_buf, int offset)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      PM_SET_BUF_GET_END_OFF(buf,offset);
   }
   static void set_get_and_end_ptr(std::streambuf *_buf, char *get, char *end)
   {
      CharBuffer *buf=static_cast<CharBuffer*>(_buf);
      PM_SET_BUF_GET_CUR(buf,get,end);
   }
   static const char* get_input_limit(std::streambuf *_buf)
   {
      return static_cast<CharBuffer*>(_buf)->input_limit;
   }
};

} // end namespace pm

#endif // _POLYMAKE_CHARBUFFER_H

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