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//===========================================================================

//

//      mbtowc.cxx

//

//      ISO standard mbtowc() routine 

//

//===========================================================================

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//===========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):     jjohnstn

// Contributors:  jjohnstn

// Date:          2000-11-01

// Purpose:       Provide ISO C mbtowc() routine

// Description: 

// Usage:       

//

//####DESCRIPTIONEND####

//

//===========================================================================

//

// This code was based upon newlib/libc/stdlib/mbtowc.c

// The following is modified from the original newlib description:

//

/*

FUNCTION

<<mbtowc>>---multibyte to wide char converter

INDEX

        mbtowc

ANSI_SYNOPSIS

        #include <stdlib.h>

        int mbtowc(wchar_t *<[pwc]>, const char *<[s]>, size_t <[n]>);

TRAD_SYNOPSIS

        #include <stdlib.h>

        int mbtowc(<[pwc]>, <[s]>, <[n]>)

        wchar_t *<[pwc]>;

        const char *<[s]>;

        size_t <[n]>;

DESCRIPTION

When CYGINT_LIBC_I18N_MB_REQUIRED is not defined, this is a minimal ANSI-conforming

implementation of <<mbtowc>>.  In this case,

only ``multi-byte character sequences'' recognized are single bytes,

and they are ``converted'' to themselves.

Each call to <<mbtowc>> copies one character from <<*<[s]>>> to

<<*<[pwc]>>>, unless <[s]> is a null pointer.  The argument n

is ignored.

When CYGINT_LIBC_I18N_MB_REQUIRED is defined, this routine calls the LC_CTYPE locale mbtowc_fn to perform

the conversion, passing a state variable to allow state dependent

decoding.  The result is based on the locale setting which may

be restricted to a defined set of locales.

RETURNS

This implementation of <<mbtowc>> returns <<0>> if

<[s]> is <<NULL>> or is the empty string;

it returns <<1>> if not CYGINT_LIBC_I18N_MB_REQUIRED or

the character is a single-byte character; it returns <<-1>>

if n is <<0>> or the multi-byte character is invalid;

otherwise it returns the number of bytes in the multibyte character.

If the return value is -1, no changes are made to the <<pwc>>

output string.  If the input is the empty string, a wchar_t nul

is placed in the output string and 0 is returned.  If the input

has a length of 0, no changes are made to the <<pwc>> output string.

PORTABILITY

<<mbtowc>> is required in the ANSI C standard.  However, the precise

effects vary with the locale.

<<mbtowc>> requires no supporting OS subroutines.

*/

// CONFIGURATION

#include <pkgconf/libc_i18n.h>     // Configuration header

// INCLUDES

#include <cyg/infra/cyg_type.h>    // Common type definitions

#include <cyg/infra/cyg_trac.h>    // Tracing support

#include <cyg/infra/cyg_ass.h>     // Assertion support

#include <locale.h>

#include <stdlib.h>                // Header for this file

#include <string.h>                // strcmp definition

#include <stddef.h>                // size_t definition

#include "internal.h"              // __current_ctype_locale

#ifdef CYGSEM_LIBC_I18N_PER_THREAD_MB

# include <pkgconf/kernel.h>       // kernel configuration

# include <cyg/kernel/thread.hxx>  // per-thread data

# include <cyg/kernel/thread.inl>  // per-thread data

# include <cyg/kernel/mutex.hxx>   // mutexes

#endif /* CYGSEM_LIBC_I18N_PER_THREAD_MB */

// TRACE

#if defined(CYGDBG_USE_TRACING) && defined(CYGNUM_LIBC_I18N_MBTOWC_TRACE_LEVEL)

static int mbtowc_trace = CYGNUM_LIBC_I18N_MBTOWC_TRACE_LEVEL;

# define TL1 (0 < mbtowc_trace)

#else

# define TL1 (0)

#endif

// STATICS

#ifdef CYGINT_LIBC_I18N_MB_REQUIRED

# ifdef CYGSEM_LIBC_I18N_PER_THREAD_MB

static volatile cyg_ucount32 mbtowc_data_index=CYGNUM_KERNEL_THREADS_DATA_MAX;

static Cyg_Mutex mbtowc_data_mutex CYG_INIT_PRIORITY(LIBC);

# else

static int cyg_libc_mbtowc_last;

# endif

#endif

// FUNCTIONS

int

mbtowc ( wchar_t *pwc, const char *s, size_t n )

{

#ifdef CYGINT_LIBC_I18N_MB_REQUIRED

  int  *state;

#endif

  int   retval;

  CYG_REPORT_FUNCNAMETYPE( "mbtowc", "returning %d" );

  CYG_REPORT_FUNCARG3( "pwc=%08x, s=%08x, n=%ud", pwc, s, n );

  if (pwc != NULL)

    CYG_CHECK_DATA_PTR( pwc, "pwc is not a valid pointer!" );

  if (s != NULL)

    CYG_CHECK_DATA_PTR( s, "s is not a valid pointer!" );

#ifdef CYGINT_LIBC_I18N_MB_REQUIRED

#ifdef CYGSEM_LIBC_I18N_PER_THREAD_MB

  Cyg_Thread *self = Cyg_Thread::self();

  // Get a per-thread data slot if we haven't got one already

  // Do a simple test before locking and retrying test, as this is a

  // rare situation

  if (CYGNUM_KERNEL_THREADS_DATA_MAX==mbtowc_data_index) {

    mbtowc_data_mutex.lock();

    if (CYGNUM_KERNEL_THREADS_DATA_MAX==mbtowc_data_index) {

      // the kernel just throws an assert if this doesn't work

      // FIXME: Should use real CDL to pre-allocate a slot at compile

      // time to ensure there are enough slots

      mbtowc_data_index = self->new_data_index();

    }

    mbtowc_data_mutex.unlock();

  } // if

  // we have a valid index now

  state = (int *)self->get_data_ptr(mbtowc_data_index);

#else

  state = &cyg_libc_mbtowc_last;

#endif

  CYG_TRACE2( TL1, "Retrieved mbtowc_last address %08x containing %d",

              state, *state );

  if (__current_ctype_locale->mbtowc_fn)

    {

      retval = __current_ctype_locale->mbtowc_fn (pwc, s, n, state);

      CYG_REPORT_RETVAL( retval );

      return retval;

    }

#endif /* CYGINT_LIBC_I18N_MB_REQUIRED */

  if (s == NULL)

    retval = 0;

  else if (n == 0)

    retval = -1;

  else

    {

      if (pwc)

        *pwc = (wchar_t) *s;

      retval =  (*s != '\0');

    }

  CYG_REPORT_RETVAL( retval );

  return retval;

} // mbtowc()

// EOF mbtowc.cxx