infsync.c

gistfile1.txt

/* zpipe.c: example of proper use of zlib's inflate() and deflate()
   Not copyrighted -- provided to the public domain
   Version 1.4  11 December 2005  Mark Adler */

/* Version history:
   1.0  30 Oct 2004  First version
   1.1   8 Nov 2004  Add void casting for unused return values
                     Use switch statement for inflate() return values
   1.2   9 Nov 2004  Add assertions to document zlib guarantees
   1.3   6 Apr 2005  Remove incorrect assertion in inf()
   1.4  11 Dec 2005  Add hack to avoid MSDOS end-of-line conversions
                     Avoid some compiler warnings for input and output buffers
 */

#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include "zlib.h"

#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
#  include <fcntl.h>
#  include <io.h>
#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
#else
#  define SET_BINARY_MODE(file)
#endif

#define CHUNK 1024


voidpf my_zalloc (voidpf opaque, unsigned items, unsigned size)
{
#if 1
    return malloc(items * size);
#else
    return calloc(size, items);
#endif
}


void my_zfree (voidpf opaque, voidpf ptr)
{
    free(ptr);
    return; 
}

int
defl(FILE* dest)
{
    int ret, flush;
    unsigned have;
    z_stream strm;
    unsigned char in[CHUNK];
    unsigned char out[CHUNK];

    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;

    ret = deflateInit2(&strm, Z_BEST_COMPRESSION, Z_DEFLATED, MAX_WBITS, MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY );    
    //fprintf(stderr, "DEF INIT %d\n", ret);
    assert(ret == Z_OK) ;
    char * message = "Mary had a little lamb";
    int length = strlen(message);
        
    int i;
    int size = 4000;
    for (i = 1; i <= size; ++i)
    {
        if (i == size/2)
            flush = Z_FULL_FLUSH;
        else if (i == size)
            flush = Z_FINISH ;
        else
            flush = Z_NO_FLUSH;

        //fprintf(stderr, "DEFLATE with flush\n");
        /* run deflate() on input until output buffer not full, finish
           compression if all of source has been read in */
        strm.avail_in = length;
        strm.next_in = message;
        do {
            strm.avail_out = CHUNK;
            strm.next_out = out;
            ret = deflate(&strm, flush);    /* no bad return value */
            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
            //fprintf(stderr, "RET %d\n" , ret);
            have = CHUNK - strm.avail_out;
            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
                (void)deflateEnd(&strm);
                return Z_ERRNO;
            }
        } while (strm.avail_out == 1);
        assert(strm.avail_in == 0);     /* all input will be used */
    }

    /* clean up and return */
    (void)deflateEnd(&strm);

    return (Z_OK);
}


/* Decompress from file source to file dest until stream ends or EOF.
   inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
   allocated for processing, Z_DATA_ERROR if the deflate data is
   invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
   the version of the library linked do not match, or Z_ERRNO if there
   is an error reading or writing the files. */
int inf(FILE *source, FILE *dest)
{
    int ret;
    unsigned have;
    z_stream strm;
    unsigned char in[CHUNK];
    unsigned char out[CHUNK];
    int found = 0;
    int chunk = 1 ;
    int one = 1 ;

    /* allocate inflate state */
#if 0
    strm.zalloc = my_zalloc;
    strm.zfree = my_zfree;
#else
    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
#endif
    strm.opaque = Z_NULL;
    strm.avail_in = 0;
    strm.next_in = Z_NULL;
    ret = inflateInit(&strm);
    if (ret != Z_OK)
        return ret;

    /* decompress until deflate stream ends or end of file */
    do {
        strm.avail_in = fread(in, 1, chunk, source);
        if (ferror(source)) {
            (void)inflateEnd(&strm);
            return Z_ERRNO;
        }
        if (strm.avail_in == 0)
            break;
        strm.next_in = in;

        /* run inflate() on first byte */
        if (one == 1)
        {
            //fprintf(stderr, "ONE BYTE %d\n", strm.avail_in);
            //chunk = CHUNK;
            one = 0;

            strm.avail_out = CHUNK;
            strm.next_out = out;
            ret = inflate(&strm, Z_NO_FLUSH);
            assert(ret == Z_OK);  
            //goto OUTER;
            continue;
        }

        /* run inflateSync() */
        if ( ! found)
        {
            do {
                strm.avail_out = CHUNK;
                strm.next_out = out;
                //fprintf(stderr, "SYNC %p %d\n", strm.next_in, strm.avail_in);
                ret = inflateSync(&strm);
                assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
                if (ret == Z_OK) 
                {
                    //fprintf(stderr, "SYNC Found %p %d\n", strm.next_in, strm.avail_in);
                    found = 1 ;
                    break;
                }
            } while (ret != Z_OK && strm.avail_in != 0);
        }

        if (strm.avail_in == 0)
            continue;

        /* run inflate() on input until output buffer not full */
        do {
            //fprintf(stderr, "INFLATE\n");
            strm.avail_out = CHUNK;
            strm.next_out = out;
            ret = inflate(&strm, Z_NO_FLUSH);
            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
            switch (ret) {
            case Z_NEED_DICT:
                ret = Z_DATA_ERROR;     /* and fall through */
            case Z_DATA_ERROR:
            case Z_MEM_ERROR:
                (void)inflateEnd(&strm);
                return ret;
            }
            have = CHUNK - strm.avail_out;
        } while (strm.avail_out == 0);

        /* done when inflate() says it's done */
    } while (ret != Z_STREAM_END);

    /* clean up and return */
    (void)inflateEnd(&strm);
    return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
}

/* report a zlib or i/o error */
void zerr(int ret)
{
    fputs("zpipe: ", stderr);
    switch (ret) {
    case Z_ERRNO:
        if (ferror(stdin))
            fputs("error reading stdin\n", stderr);
        if (ferror(stdout))
            fputs("error writing stdout\n", stderr);
        break;
    case Z_STREAM_ERROR:
        fputs("invalid compression level\n", stderr);
        break;
    case Z_DATA_ERROR:
        fputs("invalid or incomplete deflate data\n", stderr);
        break;
    case Z_MEM_ERROR:
        fputs("out of memory\n", stderr);
        break;
    case Z_VERSION_ERROR:
        fputs("zlib version mismatch!\n", stderr);
    }
}

/* compress or decompress from stdin to stdout */
int main(int argc, char **argv)
{
    int ret;

    /* avoid end-of-line conversions */
    SET_BINARY_MODE(stdin);
    SET_BINARY_MODE(stdout);

    /* do compression if no arguments */
    if (argc == 1) {
        ret = defl(stdout);
        //ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
        if (ret != Z_OK)
            zerr(ret);
        return ret;
    }

    /* do decompression if -d specified */
    else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
        ret = inf(stdin, stdout);
        if (ret != Z_OK)
            zerr(ret);
        return ret;
    }

    /* otherwise, report usage */
    else {
        fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
        return 1;
    }
}