From 0823979013457bc1dfae1087e027e154852b79d5 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Thu, 16 Jul 2026 23:21:15 +0200
Subject: Beispiel für die Streaming-API hinzugefügt
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---
 src/stream.c | 187 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 187 insertions(+)
 create mode 100644 src/stream.c

(limited to 'src')

diff --git a/src/stream.c b/src/stream.c
new file mode 100644
index 0000000..286f41a
--- /dev/null
+++ b/src/stream.c
@@ -0,0 +1,187 @@
+// 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, "compress [-d] infile outfile\n");
+}
+
+static void
+print_zlib_error(const char *operation, int error)
+{
+	if ( error == Z_ERRNO ) {
+		(void) fprintf(stderr, "%s error: %s\n", operation, strerror(errno));
+	}
+	else {
+		(void) fprintf(stderr, "%s error: %s\n", operation, zError(error));
+	}
+}
+
+int
+do_compress(FILE *in_file, FILE *out_file, int compress_level)
+{
+	z_stream strm = { 0 };
+
+	int error = deflateInit(&strm, compress_level);
+	if ( error ) {
+		return error;
+	}
+
+	unsigned char in_buffer[BUFFER_SIZE];
+	unsigned char out_buffer[BUFFER_SIZE];
+	int           flush = Z_NO_FLUSH;
+
+	do {
+		strm.avail_in = fread(in_buffer, 1, BUFFER_SIZE, in_file);
+
+		if ( ferror(in_file) ) {
+			deflateEnd(&strm);
+			return Z_ERRNO;
+		}
+
+		flush        = feof(in_file) ? Z_FINISH : Z_NO_FLUSH;
+		strm.next_in = in_buffer;
+
+		do {
+			strm.avail_out = BUFFER_SIZE;
+			strm.next_out  = out_buffer;
+
+			error = deflate(&strm, flush);
+
+			size_t have = BUFFER_SIZE - strm.avail_out;
+			if ( fwrite(out_buffer, 1, have, out_file) != have || ferror(out_file) ) {
+				deflateEnd(&strm);
+				return Z_ERRNO;
+			}
+		} while ( strm.avail_out == 0 );
+	} while ( flush != Z_FINISH );
+
+	deflateEnd(&strm);
+	return Z_OK;
+}
+
+int
+do_uncompress(FILE *in_file, FILE *out_file)
+{
+	z_stream strm = { 0 };
+
+	int error = inflateInit(&strm);
+	if ( error ) {
+		return error;
+	}
+
+	unsigned char in_buffer[BUFFER_SIZE];
+	unsigned char out_buffer[BUFFER_SIZE];
+
+	do {
+		strm.avail_in = fread(in_buffer, 1, BUFFER_SIZE, in_file);
+
+		if ( ferror(in_file) ) {
+			inflateEnd(&strm);
+			return Z_ERRNO;
+		}
+
+		if ( strm.avail_in == 0 ) {
+			break;
+		}
+
+		strm.next_in = in_buffer;
+
+		do {
+			strm.avail_out = BUFFER_SIZE;
+			strm.next_out  = out_buffer;
+
+			error = inflate(&strm, Z_NO_FLUSH);
+
+			switch ( error ) {
+			case Z_NEED_DICT:
+				error = Z_DATA_ERROR; /* and fall through */
+			case Z_DATA_ERROR:
+			case Z_MEM_ERROR:
+				(void) inflateEnd(&strm);
+				return error;
+			default:
+				break;
+			}
+
+			size_t have = BUFFER_SIZE - strm.avail_out;
+			if ( fwrite(out_buffer, 1, have, out_file) != have || ferror(out_file) ) {
+				(void) inflateEnd(&strm);
+				return Z_ERRNO;
+			}
+		} while ( strm.avail_out == 0 );
+	} while ( error != Z_STREAM_END );
+
+	inflateEnd(&strm);
+
+	return error == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
+}
+
+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();
+	}
+
+	FILE *in_file  = fopen(argv[0], "rb");
+	FILE *out_file = fopen(argv[1], "wb");
+
+	if ( !decompress ) {
+		int error = do_compress(in_file, out_file, compress_level);
+		if ( error ) {
+			print_zlib_error("compression", error);
+		}
+	}
+	else {
+		int error = do_uncompress(in_file, out_file);
+		if ( error ) {
+			print_zlib_error("extraction", error);
+		}
+	}
+
+	(void) fclose(out_file);
+	(void) fclose(in_file);
+
+	return EXIT_SUCCESS;
+}
-- 
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