// -*- C++ -*-
// $Id:$
// ---------------------------------------------------------------------------

#ifndef HEP_STRING_SRC
#define HEP_STRING_SRC

#include <iostream>
#include <string.h>

/*
 * Simplified string class.
 * It provides only few basic functions of the standard <string> and
 * is intended to be used as a replacement of the standard class where
 * full functionality of <string> is not required, but it is essential
 * to have highly portable and effective code.
 *
 * This file should be used exclusively inside *.cc files.
 * Usage inside header files can result to a clash with standard <string>.
 */
struct string {
  struct srep {
    char* s;            // pointer to data
    int   n;            // reference count
    srep() : n(1) {}
  } *p;
  
  // Default constructor.
  string() { p = new srep; p->s = 0; } 

  // Constructor from character string.
  string(const char* s) {
    p = new srep; p->s = new char[strlen(s)+1]; strcpy(p->s, s);
  }

  // Constructor from character substring.
  string(const char* s, unsigned int n) {
    p = new srep; p->s = new char[n+1]; strncpy(p->s, s, n); *(p->s+n) = '\0';
  }

  // Copy constructor from string.
  string(const string& x) { x.p->n++; p = x.p; }

  // Destructor.
  ~string() { if (--p->n == 0) { delete [] p->s; delete p; } }
    
  // Assignment from character string.
  string& operator=(const char* s) {
    if (p->n > 1) {     // disconnect self
      p->n--;
      p = new srep;
    }else{
      delete [] p->s;   // free old string
    } 
    p->s = new char[strlen(s)+1];
    strcpy(p->s, s);
    return *this;
  } 

  // Assignment from string.
  string& operator=(const string & x) {
    x.p->n++;           // protect against "st = st"
    if (--p->n == 0) { delete [] p->s; delete p; }
    p = x.p;
    return *this;
  }

  // Returns C-style character string.
  const char* c_str() const { return p->s; }
};

//
// Concatinations.
//
inline string operator+(char a, const string & b) {
  string s; s.p->s = new char[strlen(b.c_str())+2];
  s.p->s[0] = a; strcpy(s.p->s+1, b.c_str());
  return s;
}

inline string operator+(const char * a, const string & b) {
  int lena = strlen(a);
  string s; s.p->s = new char[lena+strlen(b.c_str())+1];
  strcpy(s.p->s, a); strcpy(s.p->s+lena, b.c_str());
  return s;
}

inline string operator+(const string & a, const char * b) {
  int lena = strlen(a.c_str());
  string s; s.p->s = new char[lena+strlen(b)+1];
  strcpy(s.p->s, a.c_str()); strcpy(s.p->s+lena, b);
  return s;
}

inline string operator+(const string & a, const string & b) {
  int lena = strlen(a.c_str());
  string s; s.p->s = new char[lena+strlen(b.c_str())+1];
  strcpy(s.p->s, a.c_str()); strcpy(s.p->s+lena, b.c_str());
  return s;
}
  
//
// Comparisons.
//
inline bool operator==(const string & x, const char* s) {
  return strcmp(x.p->s, s) == 0;
}
inline bool operator==(const string & x, const string & y) {
  return strcmp(x.p->s, y.p->s) == 0;
}
inline bool operator!=(const string & x, const char* s) {
  return strcmp(x.p->s, s) != 0;
}
inline bool operator!=(const string & x, const string & y) {
  return strcmp(x.p->s, y.p->s) != 0;
}

//
// Output to a stream.
//
std::ostream & operator<<(std::ostream & s, const string & x) {
  return s << x.p->s;
} 

#endif /* HEP_STRING_SRC */