几个关于zlib的小程序

#include
#include "/zlib/include/zlib.h"

// Demonstration of zlib utility functions

unsigned long file_size(char *filename)
{

FILE *pFile = fopen(filename, "rb");
fseek (pFile, 0, SEEK_END);
unsigned long size = ftell(pFile);
fclose (pFile);
return size;

}

int decompress_one_file(char *infilename, char *outfilename)
{

gzFile infile = gzopen(infilename, "rb");
FILE *outfile = fopen(outfilename, "wb");
if (!infile || !outfile) return -1;

char buffer[128];
int num_read = 0;
while ((num_read = gzread(infile, buffer, sizeof(buffer))) > 0)
{

fwrite(buffer, 1, num_read, outfile);

}

gzclose(infile);
fclose(outfile);

}

int compress_one_file(char *infilename, char *outfilename)
{

FILE *infile = fopen(infilename, "rb");
gzFile outfile = gzopen(outfilename, "wb");
if (!infile || !outfile) return -1;

char inbuffer[128];
int num_read = 0;
unsigned long total_read = 0, total_wrote = 0;
while ((num_read = fread(inbuffer, 1, sizeof(inbuffer), infile)) > 0)
{

total_read += num_read;
gzwrite(outfile, inbuffer, num_read);

}
fclose(infile);
gzclose(outfile);

printf("Read %ld bytes, Wrote %ld bytes,
Compression factor %4.2f%%\n",
total_read, file_size(outfilename),
(1.0-file_size(outfilename)*1.0/total_read)*100.0);

}


int main(int argc, char **argv)
{

compress_one_file(argv[1],argv[2]);
decompress_one_file(argv[2],argv[3]);

}