/*************************************************************************
*
*   © 2016 and later: Unicode, Inc. and others.
*   License & terms of use: http://www.unicode.org/copyright.html
*
**************************************************************************
**************************************************************************
*
*   Copyright (C) 2000-2016, International Business Machines
*   Corporation and others.  All Rights Reserved.
*
***************************************************************************
*   file name:  convsamp.c
*   encoding:   ASCII (7-bit)
*
*   created on: 2000may30
*   created by: Steven R. Loomis
*
*   Sample code for the ICU conversion routines.
*
* Note: Nothing special is needed to build this sample. Link with
*       the icu UC and icu I18N libraries. 
* 
*       I use 'assert' for error checking, you probably will want
*       something more flexible.  '***BEGIN SAMPLE***' and 
*       '***END SAMPLE***' mark pieces suitable for stand alone
*       code snippets.
*
*
*  Each test can define it's own BUFFERSIZE 
*
*/

#define DEBUG_TMI 0  /* define to 1 to enable Too Much Information */

#include <stdio.h>
#include <ctype.h>            /* for isspace, etc.    */
#include <assert.h>
#include <string.h>
#include <stdlib.h>  /* malloc */

#include "unicode/utypes.h"   /* Basic ICU data types */
#include "unicode/ucnv.h"     /* C   Converter API    */
#include "unicode/ustring.h"  /* some more string fcns*/
#include "unicode/uchar.h"    /* char names           */
#include "unicode/uloc.h"
#include "unicode/unistr.h"

#include "flagcb.h"

/* Some utility functions */
#ifndef UPRV_LENGTHOF
#define UPRV_LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
#endif

static const char16_t kNone[] = { 0x0000 };

#define U_ASSERT(x)  { if(U_FAILURE(x)) {fflush(stdout);fflush(stderr); fprintf(stderr, #x " == %s\n", u_errorName(x)); assert(U_SUCCESS(x)); }}

/* Print a char16_t if possible, in seven characters. */
void prettyPrintUChar(char16_t c)
{
  if(  (c <= 0x007F) &&
       (isgraph(c))  ) {
    printf(" '%c'   ", (char)(0x00FF&c));
  } else if ( c > 0x007F ) {
    char buf[1000];
    UErrorCode status = U_ZERO_ERROR;
    int32_t o;

    o = u_charName(c, U_EXTENDED_CHAR_NAME, buf, 1000, &status);
    if(U_SUCCESS(status) && (o>0) ) {
      buf[6] = 0;
      printf("%7s", buf);
    } else {
      printf(" ??????");
    }
  } else {
    switch((char)(c & 0x007F)) {
    case ' ':
      printf(" ' '   ");
      break;
    case '\t':
      printf(" \\t    ");
      break;
    case '\n':
      printf(" \\n    ");
      break;
    default:
      printf("  _    ");
      break;
    }
  }
}


void printUChars(const char  *name = "?", 
                 const char16_t *uch  = kNone,
                 int32_t     len   = -1 )
{
  int32_t i;

  if( (len == -1) && (uch) ) {
    len = u_strlen(uch);
  }

  printf("%5s: ", name);
  for( i = 0; i <len; i++) {
    printf("%-6d ", i);
  }
  printf("\n");

  printf("%5s: ", "uni");
  for( i = 0; i <len; i++) {
    printf("\\u%04X ", (int)uch[i]);
  }
  printf("\n");

  printf("%5s:", "ch");
  for( i = 0; i <len; i++) {
    prettyPrintUChar(uch[i]);
  }
  printf("\n");
}

void printBytes(const char  *name = "?", 
                 const char *uch  = "",
                 int32_t     len   = -1 )
{
  int32_t i;

  if( (len == -1) && (uch) ) {
    len = static_cast<int32_t>(strlen(uch));
  }

  printf("%5s: ", name);
  for( i = 0; i <len; i++) {
    printf("%-4d ", i);
  }
  printf("\n");

  printf("%5s: ", "uni");
  for( i = 0; i <len; i++) {
    printf("\\x%02X ", 0x00FF & (int)uch[i]);
  }
  printf("\n");

  printf("%5s:", "ch");
  for( i = 0; i <len; i++) {
    if(isgraph(0x00FF & (int)uch[i])) {
      printf(" '%c' ", (char)uch[i]);
    } else {
      printf("     ");
    }
  }
  printf("\n");
}

void printUChar(UChar32 ch32)
{
    if(ch32 > 0xFFFF) {
      printf("ch: U+%06X\n", ch32);
    }
    else {
      char16_t ch = (char16_t)ch32;
      printUChars("C", &ch, 1);
    }
}

/*******************************************************************
  Very simple C sample to convert the word 'Moscow' in Russian in Unicode,
  followed by an exclamation mark (!) into the KOI8-R Russian code page.

  This example first creates a char16_t String out of the Unicode chars.

  targetSize must be set to the amount of space available in the target
  buffer. After fromUChars is called, 
  len will contain the number of bytes in target[] which were
  used in the resulting codepage.  In this case, there is a 1:1 mapping
  between the input and output characters. The exclamation mark has the
  same value in both KOI8-R and Unicode.

  src: 0      1      2      3      4      5      6     
  uni: \u041C \u043E \u0441 \u043A \u0432 \u0430 \u0021 
   ch: CYRILL CYRILL CYRILL CYRILL CYRILL CYRILL   '!'  

 targ:  0    1    2    3    4    5    6  
  uni: \xED \xCF \xD3 \xCB \xD7 \xC1 \x21 
   ch:                                '!' 


Converting FROM unicode 
  to koi8-r.
  You must call ucnv_close to clean up the memory used by the
  converter.

  'len' returns the number of OUTPUT bytes resulting from the 
  conversion.
 */

UErrorCode convsample_02()
{
  printf("\n\n==============================================\n"
         "Sample 02: C: simple Unicode -> koi8-r conversion\n");


  // **************************** START SAMPLE *******************
  // "cat<cat>OK"
  char16_t source[] = { 0x041C, 0x043E, 0x0441, 0x043A, 0x0432,
                     0x0430, 0x0021, 0x0000 };
  char target[100];
  UErrorCode status = U_ZERO_ERROR;
  UConverter *conv;
  int32_t     len;

  // set up the converter
  //! [ucnv_open]
  conv = ucnv_open("koi8-r", &status);
  //! [ucnv_open]
  assert(U_SUCCESS(status));

  // convert to koi8-r
  len = ucnv_fromUChars(conv, target, 100, source, -1, &status);
  assert(U_SUCCESS(status));

  // close the converter
  ucnv_close(conv);

  // ***************************** END SAMPLE ********************
  
  // Print it out
  printUChars("src", source);
  printf("\n");
  printBytes("targ", target, len);

  return U_ZERO_ERROR;
}


UErrorCode convsample_03()
{
  printf("\n\n==============================================\n"
         "Sample 03: C: print out all converters\n");

  int32_t count;
  int32_t i;

  // **************************** START SAMPLE *******************
  count = ucnv_countAvailable();
  printf("Available converters: %d\n", count);
  
  for(i=0;i<count;i++) 
  {
    printf("%s ", ucnv_getAvailableName(i));
  }

  // ***************************** END SAMPLE ********************
  
  printf("\n");

  return U_ZERO_ERROR;
}



#define BUFFERSIZE 17 /* make it interesting :) */

/*
  Converting from a codepage to Unicode in bulk..
  What is the best way to determine the buffer size?

     The 'buffersize' is in bytes of input.
    For a given converter, dividing this by the minimum char size
    give you the maximum number of Unicode characters that could be
    expected for a given number of input bytes.
     see: ucnv_getMinCharSize()

     For example, a single byte codepage like 'Latin-3' has a 
    minimum char size of 1. (It takes at least 1 byte to represent
    each Unicode char.) So the unicode buffer has the same number of
    UChars as the input buffer has bytes.

     In a strictly double byte codepage such as cp1362 (Windows
    Korean), the minimum char size is 2. So, only half as many Unicode
    chars as bytes are needed.

     This work to calculate the buffer size is an optimization. Any
    size of input and output buffer can be used, as long as the
    program handles the following cases: If the input buffer is empty,
    the source pointer will be equal to sourceLimit.  If the output
    buffer has overflowed, U_BUFFER_OVERFLOW_ERROR will be returned. 
 */

UErrorCode convsample_05()
{
  printf("\n\n==============================================\n"
         "Sample 05: C: count the number of letters in a UTF-8 document\n");

  FILE *f;
  int32_t count;
  char inBuf[BUFFERSIZE];
  const char *source;
  const char *sourceLimit;
  char16_t *uBuf;
  char16_t *target;
  char16_t *targetLimit;
  char16_t *p;
  int32_t uBufSize = 0;
  UConverter *conv;
  UErrorCode status = U_ZERO_ERROR;
  uint32_t letters=0, total=0;

  f = fopen("data01.txt", "r");
  if(!f)
  {
    fprintf(stderr, "Couldn't open file 'data01.txt' (UTF-8 data file).\n");
    return U_FILE_ACCESS_ERROR;
  }

  // **************************** START SAMPLE *******************
  conv = ucnv_open("utf-8", &status);
  assert(U_SUCCESS(status));

  uBufSize = (BUFFERSIZE/ucnv_getMinCharSize(conv));
  printf("input bytes %d / min chars %d = %d UChars\n",
         BUFFERSIZE, ucnv_getMinCharSize(conv), uBufSize);
  uBuf = (char16_t*)malloc(uBufSize * sizeof(char16_t));
  assert(uBuf!=nullptr);

  // grab another buffer's worth
  while((!feof(f)) && 
        ((count=static_cast<int32_t>(fread(inBuf, 1, BUFFERSIZE , f))) > 0) )
  {
    // Convert bytes to unicode
    source = inBuf;
    sourceLimit = inBuf + count;
    
    do
    {
        target = uBuf;
        targetLimit = uBuf + uBufSize;
        
        ucnv_toUnicode(conv, &target, targetLimit, 
                       &source, sourceLimit, nullptr,
                       feof(f)?true:false,         /* pass 'flush' when eof */
                                   /* is true (when no more data will come) */
                       &status);
      
        if(status == U_BUFFER_OVERFLOW_ERROR)
        {
          // simply ran out of space - we'll reset the target ptr the next
          // time through the loop.
          status = U_ZERO_ERROR;
        }
        else
        {
          //  Check other errors here.
          assert(U_SUCCESS(status));
          // Break out of the loop (by force)
        }

        // Process the Unicode
        // Todo: handle UTF-16/surrogates

        for(p = uBuf; p<target; p++)
        {
          if(u_isalpha(*p))
            letters++;
          total++;
        }
    } while (source < sourceLimit); // while simply out of space
  }

  printf("%d letters out of %d total UChars.\n", letters, total);
  
  // ***************************** END SAMPLE ********************
  ucnv_close(conv);

  printf("\n");

  fclose(f);

  return U_ZERO_ERROR;
}
#undef BUFFERSIZE

#define BUFFERSIZE 1024
typedef struct
{
  UChar32  codepoint;
  uint32_t frequency;
} CharFreqInfo;

UErrorCode convsample_06()
{
  printf("\n\n==============================================\n"
         "Sample 06: C: frequency distribution of letters in a UTF-8 document\n");

  FILE *f;
  int32_t count;
  char inBuf[BUFFERSIZE];
  const char *source;
  const char *sourceLimit;
  int32_t uBufSize = 0;
  UConverter *conv;
  UErrorCode status = U_ZERO_ERROR;
  uint32_t letters=0, total=0;

  CharFreqInfo   *info;
  UChar32   charCount = 0x10000;  /* increase this if you want to handle non bmp.. todo: automatically bump it.. */
  UChar32   p;

  uint32_t ie = 0;
  uint32_t gh = 0;
  UChar32 l = 0;

  f = fopen("data06.txt", "r");
  if(!f)
  {
    fprintf(stderr, "Couldn't open file 'data06.txt' (UTF-8 data file).\n");
    return U_FILE_ACCESS_ERROR;
  }

  info = (CharFreqInfo*)malloc(sizeof(CharFreqInfo) * charCount);
  if(!info)
  {
    fprintf(stderr, " Couldn't allocate %d bytes for freq counter\n", static_cast<int>(sizeof(CharFreqInfo)*charCount));
  }

  /* reset frequencies */
  for(p=0;p<charCount;p++)
  {
    info[p].codepoint = p;
    info[p].frequency = 0;
  }

  // **************************** START SAMPLE *******************
  conv = ucnv_open("utf-8", &status);
  assert(U_SUCCESS(status));

  uBufSize = (BUFFERSIZE/ucnv_getMinCharSize(conv));
  printf("input bytes %d / min chars %d = %d UChars\n",
         BUFFERSIZE, ucnv_getMinCharSize(conv), uBufSize);

  // grab another buffer's worth
  while((!feof(f)) && 
        ((count=static_cast<int32_t>(fread(inBuf, 1, BUFFERSIZE , f))) > 0) )
  {
    // Convert bytes to unicode
    source = inBuf;
    sourceLimit = inBuf + count;
    
    while(source < sourceLimit)
    {
      p = ucnv_getNextUChar(conv, &source, sourceLimit, &status);
      if(U_FAILURE(status))
      {
        fprintf(stderr, "%s @ %d\n", u_errorName(status), total);
        status = U_ZERO_ERROR;
        continue;
      }
      U_ASSERT(status);
      total++;

      if(u_isalpha(p))
        letters++;

      if((u_tolower(l) == 'i') && (u_tolower(p) == 'e'))
        ie++;

      if((u_tolower(l) == 'g') && (u_tolower(p) == 0x0127))
        gh++;

      if(p>charCount)
      {
        fprintf(stderr, "U+%06X: oh.., we only handle BMP characters so far.. redesign!\n", p);
        free(info);
        fclose(f);
        ucnv_close(conv);
        return U_UNSUPPORTED_ERROR;
      }
      info[p].frequency++;
      l = p;
    }
  }

  fclose(f);
  ucnv_close(conv);

  printf("%d letters out of %d total UChars.\n", letters, total);
  printf("%d ie digraphs, %d gh digraphs.\n", ie, gh);

  // now, we could sort it..

  //  qsort(info, charCount, sizeof(info[0]), charfreq_compare);

  for(p=0;p<charCount;p++)
  {
    if(info[p].frequency)
    {
      printf("% 5d U+%06X ", info[p].frequency, p);
      if(p <= 0xFFFF)
      {
        prettyPrintUChar((char16_t)p);
      }
      printf("\n");
    }
  }
  free(info);
  // ***************************** END SAMPLE ********************

  printf("\n");

  return U_ZERO_ERROR;
}
#undef BUFFERSIZE


/******************************************************
  You must call ucnv_close to clean up the memory used by the
  converter.

  'len' returns the number of OUTPUT bytes resulting from the 
  conversion.
 */

UErrorCode convsample_12()
{
  printf("\n\n==============================================\n"
         "Sample 12: C: simple sjis -> unicode conversion\n");


  // **************************** START SAMPLE *******************

  char source[] = { 0x63, 0x61, 0x74, (char)0x94, 0x4C, (char)0x82, 0x6E, (char)0x82, 0x6A, 0x00 };
  char16_t target[100];
  UErrorCode status = U_ZERO_ERROR;
  UConverter *conv;
  int32_t     len;

  // set up the converter
  conv = ucnv_open("shift_jis", &status);
  assert(U_SUCCESS(status));

  // convert to Unicode
  // Note: we can use strlen, we know it's an 8 bit null terminated codepage
  target[6] = 0xFDCA;
  len = ucnv_toUChars(conv, target, 100, source, static_cast<int32_t>(strlen(source)), &status);
  U_ASSERT(status);
  // close the converter
  ucnv_close(conv);

  // ***************************** END SAMPLE ********************
  
  // Print it out
  printBytes("src", source, static_cast<int32_t>(strlen(source)) );
  printf("\n");
  printUChars("targ", target, len);

  return U_ZERO_ERROR;
}

/******************************************************************
   C: Convert from codepage to Unicode one at a time. 
*/
  
UErrorCode convsample_13()
{
  printf("\n\n==============================================\n"
         "Sample 13: C: simple Big5 -> unicode conversion, char at a time\n");


  const char sourceChars[] = { 0x7a, 0x68, 0x3d, (char)0xa4, (char)0xa4, (char)0xa4, (char)0xe5, (char)0x2e };
  //  const char sourceChars[] = { 0x7a, 0x68, 0x3d, 0xe4, 0xb8, 0xad, 0xe6, 0x96, 0x87, 0x2e };
  const char *source, *sourceLimit;
  UChar32 target;
  UErrorCode status = U_ZERO_ERROR;
  UConverter *conv = nullptr;
  int32_t srcCount=0;
  int32_t dstCount=0;
  
  srcCount = sizeof(sourceChars);

  conv = ucnv_open("Big5", &status);
  U_ASSERT(status);

  source = sourceChars;
  sourceLimit = sourceChars + sizeof(sourceChars);

  // **************************** START SAMPLE *******************


  printBytes("src", source, static_cast<int32_t>(sourceLimit - source));

  while(source < sourceLimit)
  {
    puts("");
    target = ucnv_getNextUChar (conv,
                                &source,
                                sourceLimit,
                                &status);
    
    //    printBytes("src",source,sourceLimit-source);
    U_ASSERT(status);
    printUChar(target);
    dstCount++;
  }
  
  
  // ************************** END SAMPLE *************************
  
  printf("src=%d bytes, dst=%d uchars\n", srcCount, dstCount);
  ucnv_close(conv);

  return U_ZERO_ERROR;
}




UBool convsample_20_didSubstitute(const char *source)
{
  char16_t uchars[100];
  char bytes[100];
  UConverter *conv = nullptr;
  UErrorCode status = U_ZERO_ERROR;
  uint32_t len, len2;
  UBool  flagVal;
  
  FromUFLAGContext * context = nullptr;

  printf("\n\n==============================================\n"
         "Sample 20: C: Test for substitution using callbacks\n");

  /* print out the original source */
  printBytes("src", source);
  printf("\n");

  /* First, convert from UTF8 to unicode */
  conv = ucnv_open("utf-8", &status);
  U_ASSERT(status);

  len = ucnv_toUChars(conv, uchars, 100, source, static_cast<int32_t>(strlen(source)), &status);
  U_ASSERT(status);
 
  printUChars("uch", uchars, len);
  printf("\n");

  /* Now, close the converter */
  ucnv_close(conv);

  /* Now, convert to windows-1252 */
  conv = ucnv_open("windows-1252", &status);
  U_ASSERT(status);

  /* Converter starts out with the SUBSTITUTE callback set. */

  /* initialize our callback */
  context = flagCB_fromU_openContext();

  /* Set our special callback */
  ucnv_setFromUCallBack(conv,
                        flagCB_fromU,
                        context,
                        &(context->subCallback),
                        &(context->subContext),
                        &status);

  U_ASSERT(status);

  len2 = ucnv_fromUChars(conv, bytes, 100, uchars, len, &status);
  U_ASSERT(status);

  flagVal = context->flag;  /* it's about to go away when we close the cnv */

  ucnv_close(conv);

  /* print out the original source */
  printBytes("bytes", bytes, len2);

  return flagVal; /* true if callback was called */
}

UErrorCode convsample_20()
{
  const char *sample1 = "abc\xdf\xbf";
  const char *sample2 = "abc_def";


  if(convsample_20_didSubstitute(sample1))
  {
    printf("DID substitute.\n******\n");
  }
  else
  {
    printf("Did NOT substitute.\n*****\n");
  }

  if(convsample_20_didSubstitute(sample2))
  {
    printf("DID substitute.\n******\n");
  }
  else
  {
    printf("Did NOT substitute.\n*****\n");
  }

  return U_ZERO_ERROR;
}

// 21  - C, callback, with clone and debug



UBool convsample_21_didSubstitute(const char *source)
{
  char16_t uchars[100];
  char bytes[100];
  UConverter *conv = nullptr, *cloneCnv = nullptr;
  UErrorCode status = U_ZERO_ERROR;
  uint32_t len, len2;
  UBool  flagVal = false;
  UConverterFromUCallback junkCB;
  
  FromUFLAGContext *flagCtx = nullptr, 
                   *cloneFlagCtx = nullptr;

  debugCBContext   *debugCtx1 = nullptr,
                   *debugCtx2 = nullptr,
                   *cloneDebugCtx = nullptr;

  printf("\n\n==============================================\n"
         "Sample 21: C: Test for substitution w/ callbacks & clones \n");

  /* print out the original source */
  printBytes("src", source);
  printf("\n");

  /* First, convert from UTF8 to unicode */
  conv = ucnv_open("utf-8", &status);
  U_ASSERT(status);

  len = ucnv_toUChars(conv, uchars, 100, source, static_cast<int32_t>(strlen(source)), &status);
  U_ASSERT(status);
 
  printUChars("uch", uchars, len);
  printf("\n");

  /* Now, close the converter */
  ucnv_close(conv);

  /* Now, convert to windows-1252 */
  conv = ucnv_open("windows-1252", &status);
  U_ASSERT(status);

  /* Converter starts out with the SUBSTITUTE callback set. */

  /* initialize our callback */
  /* from the 'bottom' innermost, out
   *   CNV ->  debugCtx1[debug]  ->  flagCtx[flag] -> debugCtx2[debug]  */

#if DEBUG_TMI
  printf("flagCB_fromU = %p\n", &flagCB_fromU);
  printf("debugCB_fromU = %p\n", &debugCB_fromU);
#endif

  debugCtx1 = debugCB_openContext();
   flagCtx  = flagCB_fromU_openContext();
  debugCtx2 = debugCB_openContext();

  debugCtx1->subCallback =  flagCB_fromU;  /* debug1 -> flag */
  debugCtx1->subContext  =  flagCtx;

  flagCtx->subCallback   =  debugCB_fromU; /*  flag -> debug2 */
  flagCtx->subContext    =  debugCtx2;

  debugCtx2->subCallback =  UCNV_FROM_U_CALLBACK_SUBSTITUTE;
  debugCtx2->subContext  = nullptr;

  /* Set our special callback */

  ucnv_setFromUCallBack(conv,
                        debugCB_fromU,
                        debugCtx1,
                        &(debugCtx2->subCallback),
                        &(debugCtx2->subContext),
                        &status);

  U_ASSERT(status);

#if DEBUG_TMI
  printf("Callback chain now: Converter %p -> debug1:%p-> (%p:%p)==flag:%p -> debug2:%p -> cb %p\n",
         conv, debugCtx1, debugCtx1->subCallback,
         debugCtx1->subContext, flagCtx, debugCtx2, debugCtx2->subCallback);
#endif

  cloneCnv = ucnv_safeClone(conv, nullptr, nullptr, &status);

  U_ASSERT(status);

#if DEBUG_TMI
  printf("Cloned converter from %p -> %p.  Closing %p.\n", conv, cloneCnv, conv);
#endif
  
  ucnv_close(conv);

#if DEBUG_TMI
  printf("%p closed.\n", conv);
#endif 

  U_ASSERT(status);
  /* Now, we have to extract the context */
  cloneDebugCtx = nullptr;
  cloneFlagCtx  = nullptr;

  ucnv_getFromUCallBack(cloneCnv, &junkCB, (const void **)&cloneDebugCtx);
  if(cloneDebugCtx != nullptr) {
      cloneFlagCtx = (FromUFLAGContext*) cloneDebugCtx -> subContext;
  }

  printf("Cloned converter chain: %p -> %p[debug1] -> %p[flag] -> %p[debug2] -> substitute\n",
         cloneCnv, cloneDebugCtx, cloneFlagCtx, cloneFlagCtx?cloneFlagCtx->subContext:nullptr );

  len2 = ucnv_fromUChars(cloneCnv, bytes, 100, uchars, len, &status);
  U_ASSERT(status);

  if(cloneFlagCtx != nullptr) {
      flagVal = cloneFlagCtx->flag;  /* it's about to go away when we close the cnv */
  } else {
      printf("** Warning, couldn't get the subcallback \n");
  }

  ucnv_close(cloneCnv);

  /* print out the original source */
  printBytes("bytes", bytes, len2);

  return flagVal; /* true if callback was called */
}

UErrorCode convsample_21()
{
  const char *sample1 = "abc\xdf\xbf";
  const char *sample2 = "abc_def";

  if(convsample_21_didSubstitute(sample1))
  {
    printf("DID substitute.\n******\n");
  }
  else
  {
    printf("Did NOT substitute.\n*****\n");
  }

  if(convsample_21_didSubstitute(sample2))
  {
    printf("DID substitute.\n******\n");
  }
  else
  {
    printf("Did NOT substitute.\n*****\n");
  }

  return U_ZERO_ERROR;
}


//  40-  C, cp37 -> UTF16 [data02.bin -> data40.utf16]

#define BUFFERSIZE 17 /* make it interesting :) */

UErrorCode convsample_40()
{
  printf("\n\n==============================================\n"
    "Sample 40: C: convert data02.bin from cp37 to UTF16 [data40.utf16]\n");

  FILE *f;
  FILE *out;
  int32_t count;
  char inBuf[BUFFERSIZE];
  const char *source;
  const char *sourceLimit;
  char16_t *uBuf;
  char16_t *target;
  char16_t *targetLimit;
  int32_t uBufSize = 0;
  UConverter *conv = nullptr;
  UErrorCode status = U_ZERO_ERROR;
  uint32_t inbytes=0, total=0;

  f = fopen("data02.bin", "rb");
  if(!f)
  {
    fprintf(stderr, "Couldn't open file 'data02.bin' (cp37 data file).\n");
    return U_FILE_ACCESS_ERROR;
  }

  out = fopen("data40.utf16", "wb");
  if(!out)
  {
    fprintf(stderr, "Couldn't create file 'data40.utf16'.\n");
    fclose(f);
    return U_FILE_ACCESS_ERROR;
  }

  // **************************** START SAMPLE *******************
  conv = ucnv_openCCSID(37, UCNV_IBM, &status);
  assert(U_SUCCESS(status));

  uBufSize = (BUFFERSIZE/ucnv_getMinCharSize(conv));
  printf("input bytes %d / min chars %d = %d UChars\n",
         BUFFERSIZE, ucnv_getMinCharSize(conv), uBufSize);
  uBuf = (char16_t*)malloc(uBufSize * sizeof(char16_t));
  assert(uBuf!=nullptr);

  // grab another buffer's worth
  while((!feof(f)) && 
        ((count=static_cast<int32_t>(fread(inBuf, 1, BUFFERSIZE , f))) > 0) )
  {
    inbytes += count;

    // Convert bytes to unicode
    source = inBuf;
    sourceLimit = inBuf + count;
    
    do
    {
        target = uBuf;
        targetLimit = uBuf + uBufSize;
        
        ucnv_toUnicode( conv, &target, targetLimit, 
                       &source, sourceLimit, nullptr,
                       feof(f)?true:false,         /* pass 'flush' when eof */
                                   /* is true (when no more data will come) */
                         &status);
      
        if(status == U_BUFFER_OVERFLOW_ERROR)
        {
          // simply ran out of space - we'll reset the target ptr the next
          // time through the loop.
          status = U_ZERO_ERROR;
        }
        else
        {
          //  Check other errors here.
          assert(U_SUCCESS(status));
          // Break out of the loop (by force)
        }

        // Process the Unicode
        // Todo: handle UTF-16/surrogates
        assert(fwrite(uBuf, sizeof(uBuf[0]), (target-uBuf), out) == (size_t)(target-uBuf));
        total += static_cast<uint32_t>((target-uBuf));
    } while (source < sourceLimit); // while simply out of space
  }

  printf("%d bytes in,  %d UChars out.\n", inbytes, total);
  
  // ***************************** END SAMPLE ********************
  ucnv_close(conv);

  fclose(f);
  fclose(out);
  printf("\n");

  return U_ZERO_ERROR;
}
#undef BUFFERSIZE



//  46-  C, UTF16 -> latin2 [data40.utf16 -> data46.out]

#define BUFFERSIZE 24 /* make it interesting :) */

UErrorCode convsample_46()
{
  printf("\n\n==============================================\n"
    "Sample 46: C: convert data40.utf16 from UTF16 to latin2 [data46.out]\n");

  FILE *f;
  FILE *out;
  int32_t count;
  char16_t inBuf[BUFFERSIZE];
  const char16_t *source;
  const char16_t *sourceLimit;
  char *buf;
  char *target;
  char *targetLimit;

  int32_t bufSize = 0;
  UConverter *conv = nullptr;
  UErrorCode status = U_ZERO_ERROR;
  uint32_t inchars=0, total=0;

  f = fopen("data40.utf16", "rb");
  if(!f)
  {
    fprintf(stderr, "Couldn't open file 'data40.utf16' (did you run convsample_40() ?)\n");
    return U_FILE_ACCESS_ERROR;
  }

  out = fopen("data46.out", "wb");
  if(!out)
  {
    fprintf(stderr, "Couldn't create file 'data46.out'.\n");
    fclose(f);
    return U_FILE_ACCESS_ERROR;
  }

  // **************************** START SAMPLE *******************
  conv = ucnv_open( "iso-8859-2", &status);
  assert(U_SUCCESS(status));

  bufSize = (BUFFERSIZE*ucnv_getMaxCharSize(conv));
  printf("input UChars[16] %d * max charsize %d = %d bytes output buffer\n",
         BUFFERSIZE, ucnv_getMaxCharSize(conv), bufSize);
  buf = (char*)malloc(bufSize * sizeof(char));
  assert(buf!=nullptr);

  // grab another buffer's worth
  while((!feof(f)) && 
        ((count=static_cast<int32_t>(fread(inBuf, sizeof(char16_t), BUFFERSIZE , f))) > 0) )
  {
    inchars += count;

    // Convert bytes to unicode
    source = inBuf;
    sourceLimit = inBuf + count;
    
    do
    {
        target = buf;
        targetLimit = buf + bufSize;
        
        ucnv_fromUnicode( conv, &target, targetLimit, 
                       &source, sourceLimit, nullptr,
                       feof(f)?true:false,         /* pass 'flush' when eof */
                                   /* is true (when no more data will come) */
                         &status);
      
        if(status == U_BUFFER_OVERFLOW_ERROR)
        {
          // simply ran out of space - we'll reset the target ptr the next
          // time through the loop.
          status = U_ZERO_ERROR;
        }
        else
        {
          //  Check other errors here.
          assert(U_SUCCESS(status));
          // Break out of the loop (by force)
        }

        // Process the Unicode
        assert(fwrite(buf, sizeof(buf[0]), (target-buf), out) == (size_t)(target-buf));
        total += static_cast<uint32_t>((target-buf));
    } while (source < sourceLimit); // while simply out of space
  }

  printf("%d Uchars (%d bytes) in, %d chars out.\n", inchars, static_cast<int>(inchars * sizeof(char16_t)), total);
  
  // ***************************** END SAMPLE ********************
  ucnv_close(conv);

  fclose(f);
  fclose(out);
  printf("\n");

  return U_ZERO_ERROR;
}
#undef BUFFERSIZE

#define BUFFERSIZE 219

void convsample_50() {
  printf("\n\n==============================================\n"
         "Sample 50: C: ucnv_detectUnicodeSignature\n");

  //! [ucnv_detectUnicodeSignature]
  UErrorCode err = U_ZERO_ERROR;
  UBool discardSignature = true; /* set to true to throw away the initial U+FEFF */
  char input[] = { '\xEF','\xBB', '\xBF','\x41','\x42','\x43' };
  int32_t signatureLength = 0;
  const char *encoding = ucnv_detectUnicodeSignature(input,sizeof(input),&signatureLength,&err);
  UConverter *conv = nullptr;
  char16_t output[100];
  char16_t *target = output, *out;
  const char *source = input;
  if(encoding!=nullptr && U_SUCCESS(err)){
    // should signature be discarded ?
    conv = ucnv_open(encoding, &err);
    // do the conversion
    ucnv_toUnicode(conv,
                   &target, output + UPRV_LENGTHOF(output),
                   &source, input + sizeof(input),
                   nullptr, true, &err);
    out = output;
    if (discardSignature){
      ++out; // ignore initial U+FEFF
    }
    while(out != target) {
      printf("%04x ", *out++);
    }
    puts("");
  }
  //! [ucnv_detectUnicodeSignature]
  puts("");
}



/* main */

int main()
{

  printf("Default Converter=%s\n", ucnv_getDefaultName() );
  
  convsample_02();  // C  , u->koi8r, conv
  convsample_03();  // C,   iterate

  convsample_05();  // C,  utf8->u, getNextUChar
  convsample_06(); // C freq counter thingy

  convsample_12();  // C,  sjis->u, conv
  convsample_13();  // C,  big5->u, getNextU
  
  convsample_20();  // C, callback
  convsample_21();  // C, callback debug
  
  convsample_40();  // C,   cp37 -> UTF16 [data02.bin -> data40.utf16]
  
  convsample_46();  // C,  UTF16 -> latin3 [data41.utf16 -> data46.out]

  convsample_50();  // C, detect unicode signature
  
  printf("End of converter samples.\n");
  
  fflush(stdout);
  fflush(stderr);
  
  return 0;
}