From c17b523d4710134218bca4f2fdbe8fd0cee39ecd Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Sun, 12 Jul 2026 15:19:57 +0200
Subject: Erstes Beispiel für die Benutzung von zlib
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---
 src/simple.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/simple.c

(limited to 'src/simple.c')

diff --git a/src/simple.c b/src/simple.c
new file mode 100644
index 0000000..5209841
--- /dev/null
+++ b/src/simple.c
@@ -0,0 +1,77 @@
+// Standard C
+#include <stdio.h>
+#include <stdlib.h>
+
+// System
+#include <unistd.h>
+
+// zlib
+#include <zlib.h>
+
+static void
+usage(void)
+{
+	(void) fprintf(stderr, "compress [-d] infile outfile\n");
+	exit(EXIT_FAILURE);
+}
+
+int
+main(int argc, char *argv[])
+{
+	// int compress = 1;
+	int level = 5;
+
+	int opt = 0;
+	while ( (opt = getopt(argc, argv, "dl")) != -1 ) {
+		switch ( opt ) {
+		case 'd':
+			// compress = 0; // decompress
+			break;
+
+		case 'l':
+			level = 9;
+			break;
+
+		case '?':
+		default:
+			usage();
+			break;
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	if ( argc != 2 ) {
+		usage();
+	}
+
+	FILE *in_file  = fopen(argv[0], "rb");
+	FILE *out_file = fopen(argv[1], "wb");
+
+	(void) fseek(in_file, 0, SEEK_END);
+	unsigned long insize = ftell(in_file); // max 2GB...
+	(void) fseek(in_file, 0, SEEK_SET);
+
+	unsigned char *indata = malloc(insize);
+	(void) fread(indata, 1, insize, in_file);
+
+	unsigned long  outsize = compressBound(insize);
+	unsigned char *outdata = malloc(outsize);
+
+	int res = compress2(outdata, &outsize, indata, insize, level);
+
+	if ( res == Z_OK ) {
+		(void) fwrite(outdata, 1, outsize, out_file);
+	}
+	else {
+		printf("Error: %d\n", res);
+	}
+
+	free(outdata);
+	free(indata);
+
+	(void) fclose(out_file);
+	(void) fclose(in_file);
+
+	return EXIT_SUCCESS;
+}
-- 
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