// string.cpp --
// $Id$
// This is part of Metakit, see http://www.equi4.com/metakit/

/** @file
 * yet another string implementation
 */

#include "header.h"

/* these definitions could be used instead of header.h ...
  #define q4_UNIV 1
  #define d4_inline
  #include "mk4str.h"
  #define d4_reentrant
  #define d4_assert(x)
*/

#if q4_UNIV // until end of source
/////////////////////////////////////////////////////////////////////////////

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

#ifdef _AIX
#include <strings.h>
#endif

#if !q4_INLINE
#include "mk4str.inl"
#endif
  
/////////////////////////////////////////////////////////////////////////////

#if q4_MSVC
#define strcasecmp stricmp
#elif q4_WINCE

  // MS C/C++ has this handy stricmp: a case-insensitive version of strcmp
  // This version only works with 7-bit ASCII characters 0x00 through 0x7F
    
  static int stricmp(const char* p1, const char* p2)
  {
    int c1, c2;
  
#ifdef d4_USE_UNOPTIMIZED_CODE
      do
      {
        c1 = tolower(*p1++);
        c2 = tolower(*p2++);
      } while (c1 != 0 && c1 == c2);
#else
      do
      {
        c1 = *p1++;
        c2 = *p2++;
      } while (c1 != 0 && (c1 == c2 || tolower(c1) == tolower(c2)));
        
      c1 = tolower(c1);
      c2 = tolower(c2);
#endif
      
    return c1 - c2;
  }
  
#endif

#if q4_WINCE
  const char* strrchr(const char* p, char ch)
  {
    const char* q = 0;
    while (*p)
      if (*p++ == ch)
	q = p;
    return q;
  }
#endif

/////////////////////////////////////////////////////////////////////////////
//
//  This string class implement functionality which is very similar to that
//  provided by the CString class of the Microsoft Framework Classes (MFC).
//  
//  There are also several major differences:
//  
//    1) This class uses reference counting to avoid massive copying.
//       Consequently, function return as well as assignment is very fast.
//    2) Strings of up to 255 bytes can contain any data, even null bytes.
//       Longer strings can not contain any null bytes past position 255.
//    3) This class can produce a "const char*" without overhead, but it
//       can also cast to the byte-counted "const unsigned char*" used
//       everywhere in Macintosh applications (as StringPtr, Str255, etc).
//    4) This source code is not derived from Microsoft's code in any way.
//    
//  A good way to use this class, is to always use c4_String for function
//  return values and "const [unsigned] char*" for all parameters. Together,
//  these two choices will remove the need for nearly any messy casts.
//
//  Note: MFC 4.0 has now adopted refcounts, and is a good alternative to
//      this code (but a bit bulkier, it also has Unicode support).
  
  // 2001-11-27, stop releasing nullvec, to allow MT use
  d4_reentrant static unsigned char* nullVec = 0;
    
static int fInc(unsigned char* p)
{
  ++*p;
  if (*p)
    return 1;
  
  --*p;
  return 0;
}

inline static void fDec(unsigned char* p)
{
  --*p;
  if (!*p && p != nullVec)
    delete [] p;
}

c4_String::c4_String (char ch, int n /* =1 */)
{
  if (n < 0)
    n = 0;
    
  _value = new unsigned char [n + 3];

  _value[0] = 1;              // see Init() member
  memset(_value + 2, ch, n);
  _value[1] = (unsigned char) (n <= 255 ? n : 255);
  _value[n+2] = 0;
}

c4_String::c4_String (const char* p)
{
  Init(p, p != 0 ? strlen(p) : 0);
}

c4_String::c4_String (const c4_String& s)
{
  if (fInc(s._value))
    _value = s._value;
  else
    Init(s.Data(), s.GetLength());
}

c4_String::~c4_String ()
{
  fDec(_value);
}

const c4_String& c4_String::operator= (const c4_String& s)
{
  unsigned char* oldVal = _value;
  if (fInc(s._value))
    _value = s._value;
  else
    Init(s.Data(), s.GetLength());
  fDec(oldVal);
  
  return *this;
}

c4_String operator+ (const c4_String& a, const c4_String& b)
{
  const int aCnt = a.GetLength();
  int sum = aCnt + b.GetLength();

  c4_String result ('\0', sum); // set up correct size, then fix contents
  memcpy(result._value + 2, a.Data(), aCnt);
  memcpy(result._value + 2 + aCnt, b.Data(), sum - aCnt);

  return result;
}

void c4_String::Init(const void* p, int n)
{
  if (p == NULL || n <= 0)
  {
      //  Optimization to significantly speed-up init of empty strings:
      //  share a common entry, which avoids *LOTS* of tiny mem allocs.
      //  
      //  Especially "new [...] c4_String" will benefit a lot, as well as:
      //  
      //    c4_String s;    // this would have caused a new allocation
      //    s = ...     // then immediately drops the count back
      //  
      //  2001/11/27: changed to never release this empty vector, for MT use
      //  		the new logic is to completely ignore its ref count
    
    if (!nullVec)           
    {
        // obtain a valid new empty string buffer to keep around
      unsigned char* nv = new unsigned char [3];
      nv[0] = nv[1] = nv[2] = 0;
        // only set static value after item is fully inited (avoid MT race)
      nullVec = nv;
    }
    
    _value = nullVec; // use this buffer as our empty string
    return;           // done... that was quick, wasn't it?
  }
  
  _value = new unsigned char [n + 3];

  _value[0] = 1; // many assumptions here: set the reference count to 1
  
  if (n > 0)
    memcpy(_value + 2, p, n);
  _value[1] = (unsigned char) (n <= 255 ? n : 255);
  _value[n+2] = 0;
}

int c4_String::FullLength() const
{
  int n = _value[1];
  return n < 255 ? n : n + strlen((const char*) _value + 2 + 255);
}

c4_String c4_String::Mid(int nFirst, int nCount) const
{
  if (nFirst >= GetLength())
    return c4_String ();
  
  if (nFirst + nCount > GetLength())
    nCount = GetLength() - nFirst; 
  
  if (nFirst == 0 && nCount == GetLength())
    return *this;
    
  return c4_String (Data() + nFirst, nCount);
}

c4_String c4_String::Left(int nCount) const
{
  if (nCount >= GetLength())
    return *this;
    
  return c4_String (Data(), nCount);
}

c4_String c4_String::Right(int nCount) const
{
  if (nCount >= GetLength())
    return *this;
    
  return c4_String (Data() + GetLength() - nCount, nCount);
}

bool operator== (const c4_String& a, const c4_String& b)
{
  return a._value == b._value || a.GetLength() == b.GetLength() &&
            memcmp(a.Data(), b.Data(), a.GetLength()) == 0;
}

int c4_String::Compare(const char* str) const
{
  return Data() == str ? 0 : strcmp(Data(), str);
}

int c4_String::CompareNoCase(const char* str) const
{
  return Data() == str ? 0 : strcasecmp(Data(), str);
}

int c4_String::Find(char ch) const
{
  const char* p = strchr(Data(), ch);
  return p != 0 ? p - Data() : -1;
}

int c4_String::ReverseFind(char ch) const
{
  const char* p = strrchr(Data(), ch);
  return p != 0 ? p - Data() : -1;
}

int c4_String::FindOneOf(const char* set) const
{
  const char* p = strpbrk(Data(), set);
  return p != 0 ? p - Data() : -1;
}

int c4_String::Find(const char* sub) const
{
  const char* p = strstr(Data(), sub);
  return p != 0 ? p - Data() : -1;
}

c4_String c4_String::SpanIncluding(const char* set) const
{
  return Left(strspn(Data(), set));
}

c4_String c4_String::SpanExcluding(const char* set) const
{
  return Left(strcspn(Data(), set));
}

/////////////////////////////////////////////////////////////////////////////
#endif // q4_UNIV
