/*
********************************************************************
* COPYRIGHT: 
* Copyright (c) 1997-2001, International Business Machines Corporation and
* others. All Rights Reserved.
********************************************************************
*/

#include "ucmp8.h"
#include "cmemory.h"

static int32_t findOverlappingPosition(CompactByteArray* this_obj,
                       uint32_t start, 
                       const UChar *tempIndex, 
                       int32_t tempIndexCount, 
                       uint32_t cycle);

/* internal constants*/


int32_t ucmp8_getkUnicodeCount() { return UCMP8_kUnicodeCount;}
int32_t ucmp8_getkBlockCount() { return UCMP8_kBlockCount;}
void  ucmp8_initBogus(CompactByteArray* array)
{
  CompactByteArray* this_obj = array;

  if (this_obj == NULL) return;

  this_obj->fStructSize = sizeof(CompactByteArray);
  this_obj->fArray = NULL; 
  this_obj->fIndex = NULL;
  this_obj->fCount = UCMP8_kUnicodeCount;
  this_obj->fCompact = FALSE; 
  this_obj->fBogus = TRUE;
  this_obj->fAlias = FALSE;
  this_obj->fIAmOwned = TRUE;
}

/* debug flags*/
/*=======================================================*/
void  ucmp8_init(CompactByteArray* array, int8_t defaultValue)
{
/* set up the index array and the data array.
 * the index array always points into particular parts of the data array
 * it is initially set up to point at regular block boundaries
 * The following example uses blocks of 4 for simplicity
 * Example: Expanded
 * INDEX# 0   1   2   3   4
 * INDEX  0   4   8   12  16 ...
 * ARRAY  abcdeababcedzyabcdea...
 *        |   |   |   |   |   |...
 * whenever you set an element in the array, it unpacks to this state
 * After compression, the index will point to various places in the data array
 * wherever there is a runs of the same elements as in the original
 * Example: Compressed
 * INDEX# 0   1   2   3   4
 * INDEX  0   4   1   8   2 ...
 * ARRAY  abcdeabazyabc...
 * If you look at the example, index# 2 in the expanded version points
 * to data position number 8, which has elements "bced". In the compressed
 * version, index# 2 points to data position 1, which also has "bced"
 */
  CompactByteArray* this_obj = array;
  int32_t i;
  
  if (this_obj == NULL) return;

  this_obj->fStructSize = sizeof(CompactByteArray);
  this_obj->fArray = NULL; 
  this_obj->fIndex = NULL;
  this_obj->fCount = UCMP8_kUnicodeCount;
  this_obj->fCompact = FALSE; 
  this_obj->fBogus = FALSE;
  this_obj->fAlias = FALSE;
  this_obj->fIAmOwned = TRUE;


  this_obj->fArray = (int8_t*) uprv_malloc(sizeof(int8_t) * UCMP8_kUnicodeCount);
  if (!this_obj->fArray) 
    {
      this_obj->fBogus = TRUE;
      return;
    }
  this_obj->fIndex = (uint16_t*) uprv_malloc(sizeof(uint16_t) * UCMP8_kIndexCount);
  if (!this_obj->fIndex) 
    {
      uprv_free(this_obj->fArray);
      this_obj->fArray = NULL;
      this_obj->fBogus = TRUE;
      return;
    }
  for (i = 0; i < UCMP8_kUnicodeCount; ++i) 
    {
      this_obj->fArray[i] = defaultValue;
    }
  for (i = 0; i < UCMP8_kIndexCount; ++i) 
    {
      this_obj->fIndex[i] = (uint16_t)(i << UCMP8_kBlockShift);
    }
}

CompactByteArray* ucmp8_open(int8_t defaultValue)
{
/* set up the index array and the data array.
 * the index array always points into particular parts of the data array
 * it is initially set up to point at regular block boundaries
 * The following example uses blocks of 4 for simplicity
 * Example: Expanded
 * INDEX# 0   1   2   3   4
 * INDEX  0   4   8   12  16 ...
 * ARRAY  abcdeababcedzyabcdea...
 *        |   |   |   |   |   |...
 * whenever you set an element in the array, it unpacks to this state
 * After compression, the index will point to various places in the data array
 * wherever there is a runs of the same elements as in the original
 * Example: Compressed
 * INDEX# 0   1   2   3   4
 * INDEX  0   4   1   8   2 ...
 * ARRAY  abcdeabazyabc...
 * If you look at the example, index# 2 in the expanded version points
 * to data position number 8, which has elements "bced". In the compressed
 * version, index# 2 points to data position 1, which also has "bced"
 */
  CompactByteArray* this_obj = (CompactByteArray*) uprv_malloc(sizeof(CompactByteArray));
  int32_t i;

  if (this_obj == NULL) return NULL;

  this_obj->fStructSize = sizeof(CompactByteArray);
  this_obj->fArray = NULL; 
  this_obj->fIndex = NULL;
  this_obj->fCount = UCMP8_kUnicodeCount;
  this_obj->fCompact = FALSE; 
  this_obj->fBogus = FALSE;
  this_obj->fAlias = FALSE;
  this_obj->fIAmOwned = FALSE;


  this_obj->fArray = (int8_t*) uprv_malloc(sizeof(int8_t) * UCMP8_kUnicodeCount);
  if (!this_obj->fArray) 
    {
      this_obj->fBogus = TRUE;
      return NULL;
    }
  this_obj->fIndex = (uint16_t*) uprv_malloc(sizeof(uint16_t) * UCMP8_kIndexCount);
  if (!this_obj->fIndex) 
    {
      uprv_free(this_obj->fArray);
      this_obj->fArray = NULL;
      this_obj->fBogus = TRUE;
      return NULL;
    }
  for (i = 0; i < UCMP8_kUnicodeCount; ++i) 
    {
      this_obj->fArray[i] = defaultValue;
    }
  for (i = 0; i < UCMP8_kIndexCount; ++i) 
    {
      this_obj->fIndex[i] = (uint16_t)(i << UCMP8_kBlockShift);
    }

  return this_obj;
}

CompactByteArray* ucmp8_openAdopt(uint16_t *indexArray,
                  int8_t *newValues,
                  int32_t count)
{
  CompactByteArray* this_obj = (CompactByteArray*) uprv_malloc(sizeof(CompactByteArray));

    ucmp8_initAdopt(this_obj, indexArray, newValues, count);
    this_obj->fIAmOwned = FALSE;
    return this_obj;
}

CompactByteArray* ucmp8_openAlias(uint16_t *indexArray,
                  int8_t *newValues,
                  int32_t count)
{
  CompactByteArray* this_obj = (CompactByteArray*) uprv_malloc(sizeof(CompactByteArray));

  ucmp8_initAlias(this_obj, indexArray, newValues, count);
  this_obj->fIAmOwned = FALSE;
  return this_obj;
}

/*=======================================================*/

CompactByteArray* ucmp8_initAdopt(CompactByteArray *this_obj,
                  uint16_t *indexArray,
                  int8_t *newValues,
                  int32_t count)
{
  if (this_obj) {
    this_obj->fCount = count;
    this_obj->fBogus = FALSE;
    this_obj->fStructSize = sizeof(CompactByteArray);

    this_obj->fArray = newValues;
    this_obj->fIndex = indexArray;
    this_obj->fCompact = (UBool)((count < UCMP8_kUnicodeCount) ? TRUE : FALSE);
    this_obj->fAlias = FALSE;
    this_obj->fIAmOwned = TRUE;
  }

  return this_obj;
}

CompactByteArray* ucmp8_initAlias(CompactByteArray *this_obj,
                  uint16_t *indexArray,
                  int8_t *newValues,
                  int32_t count)
{
  if (this_obj) {
    this_obj->fArray = NULL;
    this_obj->fIndex = NULL; 
    this_obj->fCount = count;
    this_obj->fBogus = FALSE;
    this_obj->fStructSize = sizeof(CompactByteArray);

    this_obj->fArray = newValues;
    this_obj->fIndex = indexArray;
    this_obj->fCompact = (UBool)((count < UCMP8_kUnicodeCount) ? TRUE : FALSE);
    this_obj->fAlias = TRUE;
    this_obj->fIAmOwned = TRUE;
  }

  return this_obj;
}

/*=======================================================*/

void ucmp8_close(CompactByteArray* this_obj) 
{
  if(this_obj != NULL) {
    if(!this_obj->fAlias) {
      if(this_obj->fArray != NULL) {
        uprv_free(this_obj->fArray);
      }
      if(this_obj->fIndex != NULL) {
        uprv_free(this_obj->fIndex);
      }
    }
    if(!this_obj->fIAmOwned) /* Called if 'init' was called instead of 'open'. */
      {
        uprv_free(this_obj);
      }
  }
}


/*=======================================================*/
 
void ucmp8_expand(CompactByteArray* this_obj) 
{
  /* can optimize later.
   * if we have to expand, then walk through the blocks instead of using Get
   * this code unpacks the array by copying the blocks to the normalized position.
   * Example: Compressed
   * INDEX# 0   1   2   3   4
   * INDEX  0   4   1   8   2 ...
   * ARRAY  abcdeabazyabc...
   *  turns into
   * Example: Expanded
   * INDEX# 0   1   2   3   4
   * INDEX  0   4   8   12  16 ...
   * ARRAY  abcdeababcedzyabcdea...
   */
    int32_t i;
    if (this_obj->fCompact) 
    {
      int8_t* tempArray;
      tempArray = (int8_t*) uprv_malloc(sizeof(int8_t) * UCMP8_kUnicodeCount);
      if (!tempArray) 
      {
          this_obj->fBogus = TRUE;
          return;
      }
      for (i = 0; i < UCMP8_kUnicodeCount; ++i) 
      {
          tempArray[i] = ucmp8_get(this_obj,(UChar)i);  /* HSYS : How expand?*/
      }
      for (i = 0; i < UCMP8_kIndexCount; ++i) 
      {
          this_obj->fIndex[i] = (uint16_t)(i<< UCMP8_kBlockShift);
      }
      uprv_free(this_obj->fArray);
      this_obj->fArray = tempArray;
      this_obj->fCompact = FALSE;
      this_obj->fAlias = FALSE;

    }
}
 

/*=======================================================*/
/* this_obj->fArray:    an array to be overlapped
 * start and count: specify the block to be overlapped
 * tempIndex:   the overlapped array (actually indices back into inputContents)
 * inputHash:   an index of hashes for tempIndex, where
 *      inputHash[i] = XOR of values from i-count+1 to i
 */
static int32_t
findOverlappingPosition(CompactByteArray* this_obj, 
            uint32_t start,
            const UChar* tempIndex,
            int32_t tempIndexCount,
            uint32_t cycle) 
{
  /* this_obj is a utility routine for finding blocks that overlap.
   * IMPORTANT: the cycle number is very important. Small cycles take a lot
   * longer to work. In some cases, they may be able to get better compaction.
   */
    
  int32_t i;
  int32_t j;
  int32_t currentCount;
  
  for (i = 0; i < tempIndexCount; i += cycle) 
    {
      currentCount = UCMP8_kBlockCount;
      if (i + UCMP8_kBlockCount > tempIndexCount) 
    {
      currentCount = tempIndexCount - i;
        } 
      for (j = 0; j < currentCount; ++j) 
    {
      if (this_obj->fArray[start + j] != this_obj->fArray[tempIndex[i + j]]) break;
        }
      if (j == currentCount) break;
    }
  
  return i;
}

UBool
ucmp8_isBogus(const CompactByteArray* this_obj)
{
  return (UBool)(this_obj == NULL || this_obj->fBogus);
}

const int8_t*
ucmp8_getArray(const CompactByteArray* this_obj)
{
  return this_obj->fArray;
}

const uint16_t*
ucmp8_getIndex(const CompactByteArray* this_obj)
{
  return this_obj->fIndex;
}

int32_t 
ucmp8_getCount(const CompactByteArray* this_obj)
{
  return this_obj->fCount;
}


void 
ucmp8_set(CompactByteArray* this_obj,
      UChar c,
      int8_t value)
{
  if (this_obj->fCompact == TRUE) 
    {
      ucmp8_expand(this_obj);
      if (this_obj->fBogus) return;
    }
  this_obj->fArray[(int32_t)c] = value;
}


void 
ucmp8_setRange(CompactByteArray* this_obj,
           UChar start,
           UChar end,
           int8_t value)
{
  int32_t i;
  if (this_obj->fCompact == TRUE) 
    {
      ucmp8_expand(this_obj);
      if (this_obj->fBogus) return;
    }
  for (i = start; i <= end; ++i) 
    {
      this_obj->fArray[i] = value;
    }
}


/*=======================================================*/
 
void 
ucmp8_compact(CompactByteArray* this_obj,
          uint32_t cycle) 
{
  if (!this_obj->fCompact) 
    {
      /* this_obj actually does the compaction.
       * it walks throught the contents of the expanded array, finding the
       * first block in the data that matches the contents of the current index.
       * As it works, it keeps an updated pointer to the last position,
       * so that it knows how big to make the final array
       * If the matching succeeds, then the index will point into the data
       * at some earlier position.
       * If the matching fails, then last position pointer will be bumped,
       * and the index will point to that last block of data.
       */
      UChar*    tempIndex;
      int32_t     tempIndexCount;
      int8_t*     tempArray;
      int32_t     iBlock, iIndex;
      
      /* fix cycle, must be 0 < cycle <= blockcount*/
      if (cycle < 0) cycle = 1;
      else if (cycle > (uint32_t)UCMP8_kBlockCount) cycle = UCMP8_kBlockCount;
      
      /* make temp storage, larger than we need*/
      tempIndex = (UChar*) uprv_malloc(sizeof(UChar)* UCMP8_kUnicodeCount);
      if (!tempIndex) 
    {
      this_obj->fBogus = TRUE;
      return;
        }               
      /* set up first block.*/
      tempIndexCount = UCMP8_kBlockCount;
      for (iIndex = 0; iIndex < UCMP8_kBlockCount; ++iIndex) 
    {
      tempIndex[iIndex] = (uint16_t)iIndex;
        }; /* endfor (iIndex = 0; .....)*/
      this_obj->fIndex[0] = 0;
      
      /* for each successive block, find out its first position in the compacted array*/
      for (iBlock = 1; iBlock < UCMP8_kIndexCount; ++iBlock) 
    {
      int32_t newCount, firstPosition, block;
      block = iBlock << UCMP8_kBlockShift;
      /*      if (debugSmall) if (block > debugSmallLimit) break;*/
      firstPosition = findOverlappingPosition(this_obj, 
                          block,
                          tempIndex,
                          tempIndexCount,
                          cycle);
      
      /* if not contained in the current list, copy the remainder
       * invariant; cumulativeHash[iBlock] = XOR of values from iBlock-kBlockCount+1 to iBlock
       * we do this_obj by XORing out cumulativeHash[iBlock-kBlockCount]
       */
      newCount = firstPosition + UCMP8_kBlockCount;
      if (newCount > tempIndexCount) 
        {
          for (iIndex = tempIndexCount; iIndex < newCount; ++iIndex) 
        {
          tempIndex[iIndex] = (uint16_t)(iIndex - firstPosition + block);
        } /* endfor (iIndex = tempIndexCount....)*/
                tempIndexCount = newCount;
            } /* endif (newCount > tempIndexCount)*/
      this_obj->fIndex[iBlock] = (uint16_t)firstPosition;
        } /* endfor (iBlock = 1.....)*/
      
      /* now allocate and copy the items into the array*/
      tempArray = (int8_t*) uprv_malloc(tempIndexCount * sizeof(int8_t));
      if (!tempArray) 
    {
      this_obj->fBogus = TRUE;
      uprv_free(tempIndex);
      return;
        }
      for (iIndex = 0; iIndex < tempIndexCount; ++iIndex) 
    {
      tempArray[iIndex] = this_obj->fArray[tempIndex[iIndex]];
        }
      uprv_free(this_obj->fArray);
      this_obj->fArray = tempArray;
      this_obj->fCount = tempIndexCount;
      
      
      /* free up temp storage*/
      uprv_free(tempIndex);
      this_obj->fCompact = TRUE;
    } /* endif (!this_obj->fCompact)*/
}

U_CAPI  uint32_t U_EXPORT2 ucmp8_flattenMem (const CompactByteArray* array, UMemoryStream *MS)
{
  int32_t size = 0;

  uprv_mstrm_write32(MS, ICU_UCMP8_VERSION);
  size += 4;
  
  uprv_mstrm_write32(MS, array->fCount);
  size += 4;
  
  uprv_mstrm_writeBlock(MS, array->fIndex, sizeof(array->fIndex[0])*UCMP8_kIndexCount);
  size += sizeof(array->fIndex[0])*UCMP8_kIndexCount;
  
  uprv_mstrm_writeBlock(MS, array->fArray, sizeof(array->fArray[0])*array->fCount);
  size += sizeof(array->fArray[0])*array->fCount;
  
  while(size%4) /* end padding */
  {
      uprv_mstrm_writePadding(MS, 1); /* Pad total so far to even size */
      size += 1;
  }

  return size;
}

/* We use sizeof(*array), etc so that this code can be as portable as 
   possible between the ucmpX_ family. 
*/

U_CAPI  void U_EXPORT2 ucmp8_initFromData(CompactByteArray *this_obj, const uint8_t **source, UErrorCode *status)
{
  uint32_t i;
  const uint8_t *oldSource = *source;

  if(U_FAILURE(*status))
    return;

 this_obj->fArray = NULL;
 this_obj->fIndex = NULL; 
 this_obj->fBogus = FALSE;
 this_obj->fStructSize = sizeof(CompactByteArray);
 this_obj->fCompact = TRUE;
 this_obj->fAlias = TRUE;
 this_obj->fIAmOwned = TRUE;
  
 i = * ((const uint32_t*) *source);
 (*source) += 4;

 if(i != ICU_UCMP8_VERSION)
 {
   *status = U_INVALID_FORMAT_ERROR;
   return;
 }
  
 this_obj->fCount = * ((const uint32_t*)*source);
 (*source) += 4;

 this_obj->fIndex = (uint16_t*) *source;
 (*source) += sizeof(this_obj->fIndex[0])*UCMP8_kIndexCount;

 this_obj->fArray = (int8_t*) *source;
 (*source) += sizeof(this_obj->fArray[0])*this_obj->fCount;

 /* eat up padding */
 while((*source-(oldSource))%4)
    (*source)++;
}