examples/PIPS/openclibz/src/compress.c

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/*
Copyright (c) 2006-2010 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of Nokia Corporation nor the names of its contributors
  may be used to endorse or promote products derived from this software
  without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Description:  
*/




#include "OpenCLibzheader.h"
#include <limits.h>

//
// GzCompress
// Compress the input file "in" and generates "out" file
//
void GzCompress(FILE   *in,gzFile out)
{
    static char buf[BUFLEN];
    int len;
    

#ifdef USE_MMAP
    /* Try first compressing with mmap. If mmap fails 
     use the normal fread loop.
     */
    if (GzCompressMmap(in, out) == Z_OK) return;
#endif
    for (;;) 
    {
        len = (int)fread(buf, 1, sizeof(buf), in);
        if (len < 0) 
        Error("error reading the file \n");
    
        if (len == 0) break;

        if (gzwrite(out, buf, (unsigned)len) != len) 
        Error("error writing to the file \n");;
        
    }
    fclose(in);
    
    if (gzclose(out) != Z_OK) // libz api to close a compressed file 
    Error("failed gzclose");
}






#ifdef USE_MMAP 

//
// GzCompressMmap
// Try compressing the input file at once using mmap. Return Z_OK 
// If success, otherwise it returns Z_ERRNO .
// 
int GzCompressMmap(FILE   * in,gzFile out)
{
    int len;
    int err;
    int ifd = fileno(in);
    caddr_t buf;    /* mmap'ed buffer for the entire input file */
    off_t buf_len;  /* length of the input file */
    struct stat sb;

    /* Determine the size of the file, needed for mmap: */
    
    if (fstat(ifd, &sb) < 0) 
    return Z_ERRNO;
    
    buf_len = sb.st_size;
    
    if (buf_len <= 0) 
    return Z_ERRNO;

    /* Now do the actual mmap: */
    
    buf =(char*) mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
    
    //mmap is an openc api 
    
    if (buf == (caddr_t)(-1)) 
    return Z_ERRNO;

    /* Compress the whole file at once: */
    len = gzwrite(out, (char *)buf, (unsigned)buf_len);

    if (len != (int)buf_len) 
    Error(gzerror(out, &err));

    munmap(buf, buf_len);
    fclose(in);
    if (gzclose(out) != Z_OK) // libz api to close a compressed file 
    Error("failed gzclose");
    
    return Z_OK;
}
#endif /* USE_MMAP */





//
// -----------------------------------------------------------------------------
// FileCompress
// Compresses the file using mode value
// -----------------------------------------------------------------------------
//
void FileCompress(char  * file,char  * mode)
{
    static char outfile[MAX_NAME_LEN];
    FILE  *in;
    gzFile out;
        char choice[3];

    strcpy(outfile, file);
    strcat(outfile, GZ_SUFFIX);

    in = fopen(file, "rb");
    if (in == NULL) 
    {    
    Error("file not found ...try again \n");
    }
    out = gzopen(outfile, mode);
    if (out == NULL) 
    {       
    Error("error opening outfile\n ");        
    }
    GzCompress(in, out);
   
    
    printf("do you want to delete the original file (y /n) \n");
    
    scanf("%s",choice);
    /*I am using scanf("%s",...) because of some problem in getchar() as 
    well as scanf("%c"...) .   I have reported the bug */
    
    if(choice[0] == 'y')
    unlink(file);
    
    printf(" Congrats .... compression done ...u can find .gz file in the same directory as of the source file\n");
}

//
// -----------------------------------------------------------------------------
// StringCompress
// Compresses the string
// This function compresses the string entered by the user and shows the
// compressed string and then decompressess it 
// Actually This function will show the content on the screen and demonstarte 
// how strings can be compressed
// -----------------------------------------------------------------------------
//

void StringCompress()
{
    Byte *compr, *uncompr;
    uLong len,comprLen,uncomprLen;
    char *hello;
     
    hello = (char *)malloc(100*sizeof(char));
  
    printf("enter the string(maximum 100 characters) to compress....\n");



    scanf("%s",hello); //accepts the string from the user
    len = (uLong)strlen(hello)+1;
    comprLen = 10 * len; 
    uncomprLen = comprLen;
    
    //memory allocation
    compr    = (Byte*)calloc((uInt)comprLen, 1);  
    uncompr  = (Byte*)calloc((uInt)uncomprLen, 1);
                
                
                
    //compress is one of the api of libz library used to compress data
    
    compress(compr, &comprLen, (const Bytef*)hello, len);

    strcpy((char*)uncompr, "garbage"); //initialization
    
    printf("compressed string is : %s\n\n", (char *)compr);

    //uncompress is one of the api of libz library used to uncompress data
    
    uncompress(uncompr, &uncomprLen, compr, comprLen);

   
    printf("press enter to uncompress it\n");
    
    getchar();
    getchar();
    
    if (strcmp((char*)uncompr, hello)) 
    {
        Error("bad uncompress\n");  
        free(compr);
        free(uncompr);        
    }
    else 
    {
        printf("uncompressed string is : %s\n", (char *)uncompr);
        free(compr);
        free(uncompr);
    }
    
}

/*  End of File */

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