1 files changed, 125 insertions, 0 deletions

diff --git a/src/gzip.c b/src/gzip.c
new file mode 100644
index 0000000..11828db
--- /dev/null
+++ b/src/gzip.c
@@ -0,0 +1,125 @@
+// Standard C
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// System
+#include <unistd.h>
+
+// zlib
+#include <zlib.h>
+
+enum { BUFFER_SIZE = 8192 };
+
+static void
+usage(void)
+{
+        (void) fprintf(stderr, "stream [-d] infile outfile\n");
+}
+
+static void
+error(const char *msg)
+{
+        perror(msg);
+        exit(EXIT_FAILURE);
+}
+
+void
+do_compress(const char *in_name, const char *out_name, int compress_level)
+{
+        FILE *in_file = fopen(in_name, "rb");
+        if ( in_file == NULL ) {
+                error("fopen() on in_file failed");
+        }
+
+        char mode[10];
+        (void) snprintf(mode, sizeof mode, "wb%d", compress_level);
+
+        gzFile out_file = gzopen(out_name, mode);
+        if ( out_file == NULL ) {
+                (void) fclose(in_file);
+                error("gzopen() on out_file failed");
+        }
+
+        unsigned char buffer[BUFFER_SIZE];
+
+        size_t bytes_read = 0;
+        while ( (bytes_read = fread(buffer, 1, BUFFER_SIZE, in_file)) != 0 ) {
+                gzfwrite(buffer, 1, bytes_read, out_file);
+        }
+
+        (void) fclose(in_file);
+        gzclose(out_file);
+}
+
+void
+do_uncompress(const char *in_name, const char *out_name)
+{
+        gzFile in_file = gzopen(in_name, "rb");
+        if ( in_file == NULL ) {
+                error("gzopen() on in_file failed");
+        }
+
+        FILE *out_file = fopen(out_name, "wb");
+        if ( out_file == NULL ) {
+                (void) gzclose(in_file);
+                error("fopen() on out_file failed");
+        }
+
+        unsigned char buffer[BUFFER_SIZE];
+
+        size_t bytes_read = 0;
+        while ( (bytes_read = gzfread(buffer, 1, BUFFER_SIZE, in_file)) != 0 ) {
+                (void) fwrite(buffer, 1, bytes_read, out_file);
+        }
+
+        gzclose(in_file);
+        (void) fclose(out_file);
+}
+
+int
+main(int argc, char *argv[])
+{
+        enum {
+                COMPRESSION_STD  = 5,
+                COMPRESSION_BEST = 9
+        };
+
+        int decompress     = 0;
+        int compress_level = COMPRESSION_STD;
+
+        int opt = 0;
+        while ( (opt = getopt(argc, argv, "dl")) != -1 ) {
+                switch ( opt ) {
+                case 'd':
+                        decompress = 1;
+                        break;
+
+                case 'l':
+                        compress_level = COMPRESSION_BEST;
+                        break;
+
+                case '?':
+                default:
+                        usage();
+                        return EXIT_SUCCESS;
+                }
+        }
+        argc -= optind;
+        argv += optind;
+
+        if ( argc != 2 ) {
+                usage();
+                return EXIT_FAILURE;
+        }
+
+        if ( !decompress ) {
+                do_compress(argv[0], argv[1], compress_level);
+        }
+        else {
+                do_uncompress(argv[0], argv[1]);
+        }
+
+        return EXIT_SUCCESS;
+}