/*
 ********************************************************************
 * COPYRIGHT: 
 * Copyright (c) 1996-1999, International Business Machines Corporation and
 * others. All Rights Reserved.
 ********************************************************************
 *
 *  uconv_bld.c:
 *
 *  Defines functions that are used in the creation/initialization/deletion
 *  of converters and related structures.
 *  uses uconv_io.h routines to access disk information
 *  is used by ucnv.h to implement public API create/delete/flushCache routines
 */


#include "ucnv_io.h"
#include "uhash.h"
#include "ucmp16.h"
#include "ucmp8.h"
#include "unicode/ucnv_bld.h"
#include "unicode/ucnv_err.h"
#include "ucnv_cnv.h"
#include "ucnv_imp.h"
#include "unicode/udata.h"
#include "unicode/ucnv.h"
#include "umutex.h"
#include "cstring.h"
#include "cmemory.h"
#include "filestrm.h"

#include <stdio.h>

static const UConverterSharedData *
converterData[UCNV_NUMBER_OF_SUPPORTED_CONVERTER_TYPES]={
    &_SBCSData, &_DBCSData, &_MBCSData, &_Latin1Data,
    &_UTF8Data, &_UTF16BEData, &_UTF16LEData, &_EBCDICStatefulData,
    &_ISO2022Data, 
    &_LMBCSData1,&_LMBCSData2, &_LMBCSData3, &_LMBCSData4, &_LMBCSData5, &_LMBCSData6,
    &_LMBCSData8,&_LMBCSData11,&_LMBCSData16,&_LMBCSData17,&_LMBCSData18,&_LMBCSData19
};

static struct {
  const char *name;
  UConverterType type;
} cnvNameType[] = {
  { "LATIN_1", UCNV_LATIN_1 },
  { "UTF8", UCNV_UTF8 },
  { "UTF16_BigEndian", UCNV_UTF16_BigEndian },
  { "UTF16_LittleEndian", UCNV_UTF16_LittleEndian },
#if U_IS_BIG_ENDIAN
  { "UTF16_PlatformEndian", UCNV_UTF16_BigEndian },
  { "UTF16_OppositeEndian", UCNV_UTF16_LittleEndian },
#else
  { "UTF16_PlatformEndian", UCNV_UTF16_LittleEndian },
  { "UTF16_OppositeEndian", UCNV_UTF16_BigEndian},
#endif
  { "ISO_2022", UCNV_ISO_2022 },
  { "LMBCS-1", UCNV_LMBCS_1 },
  { "LMBCS-2", UCNV_LMBCS_2 },
  { "LMBCS-3", UCNV_LMBCS_3 },
  { "LMBCS-4", UCNV_LMBCS_4 },
  { "LMBCS-5", UCNV_LMBCS_5 },
  { "LMBCS-6", UCNV_LMBCS_6 },
  { "LMBCS-8", UCNV_LMBCS_8 },
  { "LMBCS-11",UCNV_LMBCS_11 },
  { "LMBCS-16",UCNV_LMBCS_16 },
  { "LMBCS-17",UCNV_LMBCS_17 },
  { "LMBCS-18",UCNV_LMBCS_18 },
  { "LMBCS-19",UCNV_LMBCS_19 }
};


/*Takes an alias name gets an actual converter file name
 *goes to disk and opens it.
 *allocates the memory and returns a new UConverter object
 */
static UConverterSharedData *createConverterFromFile (const char *converterName, UErrorCode * err);

static const UConverterSharedData *getAlgorithmicTypeFromName (const char *realName);

/**
 * Un flatten shared data from a UDATA..
 */
U_CAPI  UConverterSharedData* U_EXPORT2 ucnv_data_unFlattenClone(UDataMemory *pData, UErrorCode *status);

/*initializes some global variables */
UHashtable *SHARED_DATA_HASHTABLE = NULL;

static UBool
isCnvAcceptable(void *context,
             const char *type, const char *name,
             const UDataInfo *pInfo) {
    return 
        pInfo->size>=20 &&
        pInfo->isBigEndian==U_IS_BIG_ENDIAN &&
        pInfo->charsetFamily==U_CHARSET_FAMILY &&
        pInfo->sizeofUChar==U_SIZEOF_UCHAR &&
        pInfo->dataFormat[0]==0x63 &&   /* dataFormat="cnvt" */
        pInfo->dataFormat[1]==0x6e &&
        pInfo->dataFormat[2]==0x76 &&
        pInfo->dataFormat[3]==0x74 &&
        pInfo->formatVersion[0]==4;
}

#define DATA_TYPE "cnv"

UConverterSharedData *createConverterFromFile (const char *fileName, UErrorCode * err)
{
  UDataMemory *data;
  UConverterSharedData *sharedData;

  if (err == NULL || U_FAILURE (*err)) {
    return NULL;
  }

  data = udata_openChoice(NULL, DATA_TYPE, fileName, isCnvAcceptable, NULL, err);
  if(U_FAILURE(*err))
    {
      return NULL;
    }

  sharedData = ucnv_data_unFlattenClone(data, err);
  if(U_FAILURE(*err))
    {
      udata_close(data);
      return NULL;
    }

  return sharedData;
}

void 
  copyPlatformString (char *platformString, UConverterPlatform pltfrm)
{
  switch (pltfrm)
    {
    case UCNV_IBM:
      {
        uprv_strcpy (platformString, "ibm");
        break;
      }
    default:
      {
        uprv_strcpy (platformString, "");
        break;
      }
    };

  return;
}

/*returns a converter type from a string
 */
const UConverterSharedData *
  getAlgorithmicTypeFromName (const char *realName)
{
  int i;
  for(i=0; i<sizeof(cnvNameType)/sizeof(cnvNameType[0]); ++i) {
    if(uprv_strcmp(realName, cnvNameType[i].name)==0) {
      return converterData[cnvNameType[i].type];
    }
  }
  return NULL;
}

/*Puts the shared data in the static hashtable SHARED_DATA_HASHTABLE */
void   shareConverterData (UConverterSharedData * data)
{
  UErrorCode err = U_ZERO_ERROR;
  /*Lazy evaluates the Hashtable itself */

  if (SHARED_DATA_HASHTABLE == NULL)
    {
      UHashtable* myHT = uhash_openSize (uhash_hashIChars, uhash_compareIChars,
                                         ucnv_io_countAvailableAliases(&err),
                                         &err);
      if (U_FAILURE (err)) return;
      umtx_lock (NULL);
      if (SHARED_DATA_HASHTABLE == NULL) SHARED_DATA_HASHTABLE = myHT;
      else uhash_close(myHT);
      umtx_unlock (NULL);
      
    }
  umtx_lock (NULL);
  /* ### check to see if the element is not already there! */
  uhash_put(SHARED_DATA_HASHTABLE,
             (void*) data->staticData->name, /* Okay to cast away const as long as
                                    keyDeleter == NULL */
            data,
            &err);
  umtx_unlock (NULL);

  return;
}

UConverterSharedData *getSharedConverterData (const char *name)
{
  /*special case when no Table has yet been created we return NULL */
  if (SHARED_DATA_HASHTABLE == NULL)    return NULL;
  else
    {
      return (UConverterSharedData*)uhash_get (SHARED_DATA_HASHTABLE, name);
    }
}

/*frees the string of memory blocks associates with a sharedConverter
 *if and only if the referenceCounter == 0
 */
UBool   deleteSharedConverterData (UConverterSharedData * deadSharedData)
{
    if (deadSharedData->referenceCounter > 0)
        return FALSE;
    
    /* Note: if we have a dataMemory, then that means that all ucmp's came
       from udata, and their tables will go away at the end
       of this function. So, we need to simply dealloc the UCMP8's themselves.
       We're guaranteed that they do not allocate any further memory.
       
       When we have an API to simply 'init' a ucmp8, then no action at all will
       need to happen.   --srl 

       This means that the compact arrays would have to be static fields in
       UConverterSharedData, not pointers to allocated structures.
       Markus
    */

    if (deadSharedData->impl->unload != NULL) {
        deadSharedData->impl->unload(deadSharedData);
    }

    if(deadSharedData->dataMemory != NULL)
    {
        UDataMemory *data = (UDataMemory*)deadSharedData->dataMemory;
        udata_close(data);
    }

    uprv_free (deadSharedData);
    
    return TRUE;
}

static void
parseConverterOptions(const char *inName,
                      char *cnvName, char *locale, uint32_t *pFlags) {
    char c;

    /* copy the converter name itself to cnvName */
    while((c=*inName)!=0 && c!=UCNV_OPTION_SEP_CHAR) {
        *cnvName++=c;
        ++inName;
    }
    *cnvName=0;

    /* parse options */
    if(c==UCNV_OPTION_SEP_CHAR) {
        ++inName;
        for(;;) {
            /* inName is behind an option separator */
            if(uprv_strncmp(inName, "locale=", 7)==0) {
                /* do not modify locale itself in case we have multiple locale options */
                char *dest=locale;

                /* copy the locale option value */
                inName+=7;
                for(;;) {
                    c=*inName;
                    if(c!=0) {
                        ++inName;
                        if(c!=UCNV_OPTION_SEP_CHAR) {
                            *dest++=c;
                        } else {
                            *dest=0;
                            break;
                        }
                    } else {
                        *dest=0;
                        return;
                    }
                }
            } else {
                /* ignore any other options until we define some */
                for(;;) {
                    c=*inName;
                    if(c!=0) {
                        ++inName;
                        if(c==UCNV_OPTION_SEP_CHAR) {
                            break;
                        }
                    } else {
                        return;
                    }
                }
            }
        }
    }
}

/*Logic determines if the converter is Algorithmic AND/OR cached
 *depending on that:
 * -we either go to get data from disk and cache it (Data=TRUE, Cached=False)
 * -Get it from a Hashtable (Data=X, Cached=TRUE)
 * -Call dataConverter initializer (Data=TRUE, Cached=TRUE)
 * -Call AlgorithmicConverter initializer (Data=FALSE, Cached=TRUE)
 */
UConverter *
  createConverter (const char *converterName, UErrorCode * err)
{
  char cnvName[100], locale[20];
  const char *realName;
  UConverter *myUConverter = NULL;
  UConverterSharedData *mySharedConverterData = NULL;
  UErrorCode internalErrorCode = U_ZERO_ERROR;

  if (U_FAILURE (*err))
    return NULL;

  locale[0] = 0;

  /* In case "name" is NULL we want to open the default converter. */
  if (converterName == NULL) {
    realName = ucnv_io_getDefaultConverterName();
    if (realName == NULL) {
      *err = U_MISSING_RESOURCE_ERROR;
      return NULL;
    }
    /* the default converter name is already canonical */
  } else {
    /* separate the converter name from the options */
    parseConverterOptions(converterName, cnvName, locale, NULL);

    /* get the canonical converter name */
    realName = ucnv_io_getConverterName(cnvName, &internalErrorCode);
    if (U_FAILURE(internalErrorCode) || realName == NULL) {
      /*
       * set the input name in case the converter was added
       * without updating the alias table, or when there is no alias table
       */
      realName = cnvName;
    }
  }

  /* separate the converter name from the options */
  if(realName != cnvName) {
    parseConverterOptions(realName, cnvName, locale, NULL);
    realName = cnvName;
  }

  /* get the shared data for an algorithmic converter, if it is one */
  mySharedConverterData = (UConverterSharedData *)getAlgorithmicTypeFromName (realName);
  if (mySharedConverterData == NULL)
    {
      /* it is a data-based converter, get its shared data */
      mySharedConverterData = getSharedConverterData (realName);
      if (mySharedConverterData == NULL)
        {
          /*Not cached, we need to stream it in from file */
          mySharedConverterData = createConverterFromFile (realName, err);
          if (U_FAILURE (*err) || (mySharedConverterData == NULL))
            {
              return NULL;
            }
          else
            {
              /* share it with other library clients */
              shareConverterData (mySharedConverterData);
            }
        }
      else
        {
          /* ### this is unsafe: the shared data could have been deleted since sharing or getting it - these operations should increase the counter! */
          /* update the reference counter: one more client */
          umtx_lock (NULL);
          mySharedConverterData->referenceCounter++;
          umtx_unlock (NULL);
        }
    }

  /* allocate the converter */
  myUConverter = (UConverter *) uprv_malloc (sizeof (UConverter));
  if (myUConverter == NULL)
    {
      if (mySharedConverterData->referenceCounter != ~0) {
        umtx_lock (NULL);
        --mySharedConverterData->referenceCounter;
        umtx_unlock (NULL);
      }
      *err = U_MEMORY_ALLOCATION_ERROR;
      return NULL;
    }

  /* initialize the converter */
  uprv_memset(myUConverter, 0, sizeof(UConverter));
  myUConverter->sharedData = mySharedConverterData;
  myUConverter->mode = UCNV_SI;
  myUConverter->fromCharErrorBehaviour = (UConverterToUCallback) UCNV_TO_U_CALLBACK_SUBSTITUTE;
  myUConverter->fromUCharErrorBehaviour = (UConverterFromUCallback) UCNV_FROM_U_CALLBACK_SUBSTITUTE;
  myUConverter->toUnicodeStatus = myUConverter->sharedData->toUnicodeStatus;
  myUConverter->subCharLen = myUConverter->sharedData->staticData->subCharLen;
  uprv_memcpy (myUConverter->subChar, myUConverter->sharedData->staticData->subChar, myUConverter->subCharLen);

  if(myUConverter != NULL && myUConverter->sharedData->impl->open != NULL) {
    myUConverter->sharedData->impl->open(myUConverter, realName, locale, err);
    if(U_FAILURE(*err)) {
      ucnv_close(myUConverter);
      return NULL;
    }
  }

  return myUConverter;
}

UConverterSharedData* ucnv_data_unFlattenClone(UDataMemory *pData, UErrorCode *status)
{
    const uint8_t *raw = (const uint8_t *)udata_getMemory(pData);
    const UConverterStaticData *source = (const UConverterStaticData *) raw;
    UConverterSharedData *data;
    UConverterType type = source->conversionType;

    if(U_FAILURE(*status))
        return NULL;

    if( (uint16_t)type >= UCNV_NUMBER_OF_SUPPORTED_CONVERTER_TYPES ||
        converterData[type]->referenceCounter != 1 ||
        source->structSize != sizeof(UConverterStaticData))
    {
        *status = U_INVALID_TABLE_FORMAT;
        return NULL;
    }

    data = (UConverterSharedData *)uprv_malloc(sizeof(UConverterSharedData));
    if(data == NULL) {
        *status = U_MEMORY_ALLOCATION_ERROR;
        return NULL;
    }

    /* copy initial values from the static structure for this type */
    uprv_memcpy(data, converterData[type], sizeof(UConverterSharedData));

    /* ### it would be much more efficient if the table were a direct member, not a pointer */
    data->table = (UConverterTable *)uprv_malloc(sizeof(UConverterTable));
    if(data->table == NULL) {
        uprv_free(data);
        *status = U_MEMORY_ALLOCATION_ERROR;
        return NULL;
    }
    
    data->staticData = source;

    /* fill in fields from the loaded data */
    data->dataMemory = (void*)pData; /* for future use */

    if(data->impl->load != NULL) {
        data->impl->load(data, raw + source->structSize, status);
        if(U_FAILURE(*status)) {
            uprv_free(data);
            return NULL;
        }
    }
    return data;
}