About

SophiaSCALE for BREW is for compressing data used for BREW Application.

Contents

The following files are included in the package.

• SophiaScale.h (include file)
• ScaleOptions.h (compression parameter)
• ScaleDecorder.c (decode routine)
• ScaleEncorder.c (compress routine)
• ScaleTest.c (test program)
• Makefile (makefile for compile)
• Readme.txt (user's guide)

Environment

Compiler: RVCTB 1.2 Build 848

Usage Procedure

• Include SophiaScale.h in your application's project file.
• Encode (compress)
  

  void *data    ... Address of original data
  int data_size ... Size of original data
  
  void *compressed_data;
  SSDataSize compressed_size;
  
  //Check the worst sum of compressed data
  compressed_size = ScaleEstimateEncodeSize(data_size);
  //allocate memory
  compressed_data = malloc(compressed_size);
  //Actual size of compressed data goes into compressed_size
  compressed_size = ScaleEncoder(compressed_data, 
                                 compressed_size,
                                 data, 
                                 data_size);
  if (compressed_size < 0)
     error handling
  //Release unused memory
  compressed_data = realloc(compressed_data, compressed_size);
  
  

• Decode (decompress)
  

  void *cdata    ... Address of compressed data
  int cdata_size ... Size of compressed data
  
  void *orig_data;
  SSDataSize orig_size;
  
  //Check the size of original data
  orig_size = ScaleEstimateEncodeSize(cdata);
  //allocate memory
  orig_data = malloc(orig_size);
  //decode+（size of actual compressed data goes into orig_size)
  orig_size = ScaleDecoder(orig_data, orig_size, data, data_size);
  if (orig_size < 0)
     error handling
  //Release unused memory (not required when decoding)
  //orig_data = realloc(orig_data, orig_size);
  

Error Code

When errors occur during operation, negative values will be returned.

Error Code	Meaning
SSERR_NO_MEMORY	Failed to allocate memory (malloc)
SSERR_NO_ROOM	Overflowed from the allocated memory area
SSERR_DATA_BROKEN	Error occurred during decompression.File might be broken.

Caution

• ScaleEstimateEncodeSize() returns the worst possible size of compressed data.
  The actual compressed data will be half of this size.
• ScaleEncoder allocates a great amount of memory, twice as big as return value of ScaleEstimateEncodeSize(). Please be aware of memory vacancy when compressing huge data.
• In the current implementation of SophiaSCALE, the use of malloc is minimized. Instead, the stack is heavily used, which leaves the possibility of Stack Overflow open.
  
• Edit ScaleOptions.h to change the compression parameters.