📄 cfs_tool.c
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/************************************************************************
*
* CopyrIght (c) 1993 - 2001 Accelerated Technology, Inc.
*
* PROPRIETARY RIGHTS of Accelerated Technology are involved in the subject
* matter of this material. All manufacturing, reproduction, use and sales
* rights pertaining to this subject matter are governed by the license
* agreement. The recipient of this software implicity accepts the terms
* of the license.
*
*************************************************************************/
/************************************************************************
*
* FILE NAME VERSION
*
* cfs_tool.c - Compression File System Tool 1.5
*
* COMPONENT
*
* Nucleus WebServ
*
* DESCRIPTION
*
* This file holds functions that are used in the process of
* compressing and decompressing files.
*
* DATA STRUCTURES
*
* Totals A global array to hold the
* cumulative totals.
*
* FUNCTIONS
*
* CFS_Compress Compresses a file in memory or
* magnetic media.
* CFS_Decompress Decompresses a file in memory or
* magnetic media.
* CFS_Fatal_Error Prints an Error message to a
* file.
* CFS_Close_Output_Bit_File Closes Output Bit File.
* CFS_Compress_File Compresses Input Bit File.
* CFS_Open_Input_Bit_File Open Input Bit file.
* CFS_Open_Output_Bit_File Open the Output Bit file.
* CFS_Expand_File Expand compressed file.
* CFS_Build_Model Builds the compressed file model.
* CFS_Init_Arithmetic_Encoder Initializes the state of the
* Arithmetic Encoder.
* CFS_Convert_Int_To_Symbol Converts an integer count into a
* symbol structure.
* CFS_Encode_Symbol Encodes a symbol for file
* compression.
* CFS_Flush_Arithmetic_Encoder Flushes Arithmetic encoder.
* CFS_Output_Bits Outputs a bit based on a count
* and a specific code.
* CFS_Input_Counts Reads the number of counts from
* the input file builds the table
* of cumulative counts.
* CFS_Init_Arithmetic_Decoder Initializes the state of the
* Arithmetic Decoder.
* CFS_Get_Symbol_Scale Retrieves symbol scale.
* CFS_Get_Current_Count Retrieves current Count.
* CFS_Convert_Symbol_To_Int Converts symbol to integer.
* CFS_Remove_Symbol_From_Stream Removes a charcter from the input
* stream.
* CFS_Buf_Putc Puts a character in a buffer.
* CFS_Count_Bytes Counts number of bytes.
* CFS_Scale_Counts Scales the number of byte counts.
* CFS_Output_Counts Outputs the byte counts.
* CFS_Build_Totals Builds the table of cumulative
* totals.
* CFS_Buf_Getc Gets a character from the input
* bit_file.
* CFS_Input_Bit Reads a bit from an input file
* stream.
* CFS_Input_Bits Inputs a bit based on a count.
* CFS_Output_Bit Outputs a Specific bit in the
* file stream.
*
* DEPENDENCIES
*
* nu_websrv.h
*
************************************************************************/
#include "webserv/inc/nu_websr.h"
#ifdef WS_FILE_COMPRESSION
/*
* Internal function prototypes.
*/
static VOID CFS_Compress_File( WS_BIT_FILE * buf_input, WS_BIT_FILE * buf_output );
static VOID CFS_Expand_File( WS_BIT_FILE *buf_input, WS_BIT_FILE *buf_output );
static VOID CFS_Open_Input_Bit_File( WS_BIT_FILE *name,CHAR * buf, INT32 length );
static VOID CFS_Open_Output_Bit_File( WS_BIT_FILE *name, CHAR * buf );
static VOID CFS_Output_Bit( WS_BIT_FILE *bit_file, INT bit );
static VOID CFS_Output_Bits( WS_BIT_FILE *bit_file, UINT32 code, INT count );
static INT CFS_Input_Bit( WS_BIT_FILE *bit_file );
static VOID CFS_Close_Output_Bit_File( WS_BIT_FILE *bit_file );
static INT CFS_Buf_Getc( WS_BIT_FILE *bitfile );
static INT CFS_Buf_Putc( unsigned int out, WS_BIT_FILE *bitfile );
static VOID CFS_Build_Model( WS_BIT_FILE *input, WS_BIT_FILE *output );
static VOID CFS_Scale_Counts( UINT32 counts[], UINT8 scaled_counts[] );
static VOID CFS_Build_Totals( UINT8 scaled_counts[] );
static VOID CFS_Count_Bytes( WS_BIT_FILE *input, UINT32 counts[] );
static VOID CFS_Output_Counts( WS_BIT_FILE *output, UINT8 scaled_counts[] );
static VOID CFS_Input_Counts( WS_BIT_FILE *input );
static VOID CFS_Convert_Int_To_Symbol( INT symbol, WS_SYMBOL *s );
static VOID CFS_Get_Symbol_Scale( WS_SYMBOL *s );
static INT CFS_Convert_Symbol_To_Int( INT count, WS_SYMBOL *s );
static VOID CFS_Init_Arithmetic_Encoder( VOID );
static VOID CFS_Encode_Symbol( WS_BIT_FILE *stream, WS_SYMBOL *s );
static VOID CFS_Flush_Arithmetic_Encoder( WS_BIT_FILE *stream );
static INT16 CFS_Get_Current_Count( WS_SYMBOL *s );
static VOID CFS_Init_Arithmetic_Decoder( WS_BIT_FILE *stream );
static VOID CFS_Remove_Symbol_From_Stream( WS_BIT_FILE *stream, WS_SYMBOL *s );
static VOID CFS_Fatal_Error( CHAR *s);
#define CFS_END_OF_STREAM 256
#define CFS_PACIFIER_COUNT 2047
#ifndef SEEK_SET
#define SEEK_SET 0
#endif
/*
* These four variables define the current state of the arithmetic
* coder/decoder.
*/
static UINT16 CFS_Code; /* The present input code value */
static UINT16 CFS_Low; /* Start of the current code range */
static UINT16 CFS_High; /* End of the current code range */
static INT32 CFS_Underflow_Bits; /* Number of underflow bits pending */
static INT16 CFS_Totals[258]; /* The cumulative totals */
/************************************************************************
*
* FUNCTION
*
* CFS_Compress
*
* DESCRIPTION
*
* Function used to compress an html, gif, jpeg, or text files. This
* function compresses the files for the in memory file system and
* os dependent file system.
*
* INPUTS
*
* *inbuf Pointer to the input buffer where the
* file is coming from. Usually
* memory.
* length The length of the data to be
* compressed.
* mode Flag that idicates whether
* Not Output or Output
* *outbuf Pointer to the output buffer where the
* the memory is to be stored.
*
* OUTPUTS
*
* out.length+1 Pointer to next position to be
* compressed.
*
************************************************************************/
INT32 CFS_Compress( INT mode, CHAR *inbuf, CHAR *outbuf, INT32 length )
{
WS_BIT_FILE out;
WS_BIT_FILE in;
CFS_Open_Output_Bit_File( &out, outbuf );
out.mode = mode;
CFS_Open_Input_Bit_File( &in, inbuf, length );
CFS_Compress_File( &in, &out );
CFS_Close_Output_Bit_File( &out );
return( out.length + 1 );
}
/************************************************************************
*
* FUNCTION
*
* CFS_Decompress
*
* DESCRIPTION
*
* Function to decompress files resident in the file system.
*
* INPUTS
*
* *req Pointer to Request structure that
* holds all information pertaining
* to the HTTP request.
* *inbuf Pointer to the input buffer to be
* decompressed.
* *outbuf Pointer to the output buffer of
* decompressed file.
* ilen Length of the input buffer.
* olen Length of the output buffer.
*
* OUTPUTS
*
* NU_SUCCESS
*
***********************************************************************/
INT CFS_Decompress(WS_REQUEST *req, CHAR *inbuf, CHAR *outbuf, INT32 inlen)
{
WS_BIT_FILE in;
WS_BIT_FILE out;
#ifdef NU_WEBSERV_DEBUG
printf( "CFS_Decompress(%x %x %d) \n", inbuf, outbuf, inlen );
#endif
CFS_Open_Output_Bit_File( &out, outbuf );
CFS_Open_Input_Bit_File( &in, inbuf, inlen );
out.fd = req;
out.mode = WS_NET_OUTPUT | WS_DONT_OUTPUT;
out.length = 0;
CFS_Expand_File( &in, &out );
CFS_Close_Output_Bit_File( &out );
return(NU_SUCCESS);
}
/************************************************************************
*
* FUNCTION
*
* CFS_Compress_File
*
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