/************************************************************************************[ParseUtils.h]
Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson
Copyright (c) 2007-2010, Niklas Sorensson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
**************************************************************************************************/

#ifndef Manysat_ParseUtils_h
#define Manysat_ParseUtils_h

#include <stdlib.h>
#include <stdio.h>

#include <zlib.h>

namespace Manysat {

//-------------------------------------------------------------------------------------------------
// A simple buffered character stream class:

static const int buffer_size = 1048576;


class StreamBuffer {
    gzFile        in;
    unsigned char buf[buffer_size];
    int           pos;
    int           size;

    void assureLookahead() {
        if (pos >= size) {
            pos  = 0;
            size = gzread(in, buf, sizeof(buf)); } }

public:
    explicit StreamBuffer(gzFile i) : in(i), pos(0), size(0) { assureLookahead(); }

    int  operator *  () const { return (pos >= size) ? EOF : buf[pos]; }
    void operator ++ ()       { pos++; assureLookahead(); }
    int  position    () const { return pos; }
};


//-------------------------------------------------------------------------------------------------
// End-of-file detection functions for StreamBuffer and char*:


static inline bool isEof(StreamBuffer& in) { return *in == EOF;  }
static inline bool isEof(const char*   in) { return *in == '\0'; }

//-------------------------------------------------------------------------------------------------
// Generic parse functions parametrized over the input-stream type.


template<class B>
static void skipWhitespace(B& in) {
    while ((*in >= 9 && *in <= 13) || *in == 32)
        ++in; }


template<class B>
static void skipLine(B& in) {
    for (;;){
        if (isEof(in)) return;
        if (*in == '\n') { ++in; return; }
        ++in; } }


template<class B>
static int parseInt(B& in) {
    int     val = 0;
    bool    neg = false;
    skipWhitespace(in);
    if      (*in == '-') neg = true, ++in;
    else if (*in == '+') ++in;
    if (*in < '0' || *in > '9') fprintf(stderr, "PARSE ERROR! Unexpected char: %c\n", *in), exit(3);
    while (*in >= '0' && *in <= '9')
        val = val*10 + (*in - '0'),
        ++in;
    return neg ? -val : val; }


// String matching: in case of a match the input iterator will be advanced the corresponding
// number of characters.
template<class B>
static bool match(B& in, const char* str) {
    int i;
    for (i = 0; str[i] != '\0'; i++)
        if (in[i] != str[i])
            return false;

    in += i;

    return true; 
}

// String matching: consumes characters eagerly, but does not require random access iterator.
template<class B>
static bool eagerMatch(B& in, const char* str) {
    for (; *str != '\0'; ++str, ++in)
        if (*str != *in)
            return false;
    return true; }


//=================================================================================================
}

#endif
