From f010c2032f4054f2eae544166814d95c8c5ff3d9 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Sun, 12 Jul 2026 22:55:49 +0200
Subject: compress und uncompress Funktionen

---
 src/simple.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 71 insertions(+), 22 deletions(-)

(limited to 'src/simple.c')

diff --git a/src/simple.c b/src/simple.c
index 5209841..36f7e48 100644
--- a/src/simple.c
+++ b/src/simple.c
@@ -15,21 +15,85 @@ usage(void)
 	exit(EXIT_FAILURE);
 }
 
+unsigned long
+get_filesize(FILE *file)
+{
+	(void) fseek(file, 0, SEEK_END);
+	unsigned long size = ftell(file);
+	(void) fseek(file, 0, SEEK_SET);
+	return size;
+}
+
+void
+do_compress(FILE *in_file, FILE *out_file, int compress_level)
+{
+	const unsigned long in_size = get_filesize(in_file);
+
+	(void) fwrite(&in_size, sizeof in_size, 1, out_file);
+
+	unsigned char *in_data = malloc(in_size);
+	(void) fread(in_data, 1, in_size, in_file);
+
+	unsigned long  out_size = compressBound(in_size);
+	unsigned char *out_data = malloc(out_size);
+
+	const int error = compress2(out_data, &out_size, in_data, in_size, compress_level);
+
+	if ( !error ) {
+		(void) fwrite(out_data, 1, out_size, out_file);
+	}
+	else {
+		printf("Error: %d\n", error);
+	}
+
+	free(out_data);
+	free(in_data);
+}
+
+void
+do_uncompress(FILE *in_file, FILE *out_file)
+{
+	const unsigned long in_size = get_filesize(in_file);
+
+	unsigned char *in_data = malloc(in_size);
+	(void) fread(in_data, 1, in_size, in_file);
+
+	unsigned long  out_size = *(unsigned long *) in_data;
+	unsigned char *out_data = malloc(out_size);
+
+	unsigned long tmp = in_size - sizeof(unsigned long);
+
+	const int error = uncompress2(out_data,
+	                              &out_size,
+	                              in_data + sizeof(unsigned long),
+	                              &tmp);
+
+	if ( !error ) {
+		(void) fwrite(out_data, 1, out_size, out_file);
+	}
+	else {
+		printf("Error: %d\n", error);
+	}
+
+	free(out_data);
+	free(in_data);
+}
+
 int
 main(int argc, char *argv[])
 {
-	// int compress = 1;
-	int level = 5;
+	int decompress     = 0;
+	int compress_level = 5;
 
 	int opt = 0;
 	while ( (opt = getopt(argc, argv, "dl")) != -1 ) {
 		switch ( opt ) {
 		case 'd':
-			// compress = 0; // decompress
+			decompress = 1;
 			break;
 
 		case 'l':
-			level = 9;
+			compress_level = 9;
 			break;
 
 		case '?':
@@ -48,28 +112,13 @@ main(int argc, char *argv[])
 	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);
+	if ( !decompress ) {
+		do_compress(in_file, out_file, compress_level);
 	}
 	else {
-		printf("Error: %d\n", res);
+		do_uncompress(in_file, out_file);
 	}
 
-	free(outdata);
-	free(indata);
-
 	(void) fclose(out_file);
 	(void) fclose(in_file);
 
-- 
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