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@Ilgrim Ilgrim/test.sh forked from arq5x/test.sh
Created Jul 15, 2019

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Compress and then Decompress a string with zlib.
# compile
$ g++ zlib-example.cpp -lz -o zlib-example
# run
$ ./zlib-example
Uncompressed size is: 36
Uncompressed string is: Hello Hello Hello Hello Hello Hello!
----------
Compressed size is: 13
Compressed string is: x��H���W��G*2
----------
Uncompressed size is: 36
Uncompressed string is: Hello Hello Hello Hello Hello Hello!
#include <stdio.h>
#include <string.h> // for strlen
#include <assert.h>
#include "zlib.h"
// adapted from: http://stackoverflow.com/questions/7540259/deflate-and-inflate-zlib-h-in-c
int main(int argc, char* argv[])
{
// original string len = 36
char a[50] = "Hello Hello Hello Hello Hello Hello!";
// placeholder for the compressed (deflated) version of "a"
char b[50];
// placeholder for the UNcompressed (inflated) version of "b"
char c[50];
printf("Uncompressed size is: %lu\n", strlen(a));
printf("Uncompressed string is: %s\n", a);
printf("\n----------\n\n");
// STEP 1.
// deflate a into b. (that is, compress a into b)
// zlib struct
z_stream defstream;
defstream.zalloc = Z_NULL;
defstream.zfree = Z_NULL;
defstream.opaque = Z_NULL;
// setup "a" as the input and "b" as the compressed output
defstream.avail_in = (uInt)strlen(a)+1; // size of input, string + terminator
defstream.next_in = (Bytef *)a; // input char array
defstream.avail_out = (uInt)sizeof(b); // size of output
defstream.next_out = (Bytef *)b; // output char array
// the actual compression work.
deflateInit(&defstream, Z_BEST_COMPRESSION);
deflate(&defstream, Z_FINISH);
deflateEnd(&defstream);
// This is one way of getting the size of the output
printf("Compressed size is: %lu\n", strlen(b));
printf("Compressed string is: %s\n", b);
printf("\n----------\n\n");
// STEP 2.
// inflate b into c
// zlib struct
z_stream infstream;
infstream.zalloc = Z_NULL;
infstream.zfree = Z_NULL;
infstream.opaque = Z_NULL;
// setup "b" as the input and "c" as the compressed output
infstream.avail_in = (uInt)((char*)defstream.next_out - b); // size of input
infstream.next_in = (Bytef *)b; // input char array
infstream.avail_out = (uInt)sizeof(c); // size of output
infstream.next_out = (Bytef *)c; // output char array
// the actual DE-compression work.
inflateInit(&infstream);
inflate(&infstream, Z_NO_FLUSH);
inflateEnd(&infstream);
printf("Uncompressed size is: %lu\n", strlen(c));
printf("Uncompressed string is: %s\n", c);
// make sure uncompressed is exactly equal to original.
assert(strcmp(a,c)==0);
return 0;
}
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