Fehlerbehandlung hinzugefügt

1 files changed, 55 insertions, 20 deletions

diff --git a/src/simple.c b/src/simple.c
index 36f7e48..da79562 100644
--- a/src/simple.c
+++ b/src/simple.c
@@ -1,6 +1,7 @@
 // Standard C
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 // System
 #include <unistd.h>
@@ -12,38 +13,61 @@ static void
 usage(void)
 {
         (void) fprintf(stderr, "compress [-d] infile outfile\n");
+}
+
+static void
+error(const char *msg)
+{
+        perror(msg);
         exit(EXIT_FAILURE);
 }
 
-unsigned long
+size_t
 get_filesize(FILE *file)
 {
-        (void) fseek(file, 0, SEEK_END);
-        unsigned long size = ftell(file);
-        (void) fseek(file, 0, SEEK_SET);
-        return size;
+        long current_pos = ftell(file);
+        if ( current_pos == -1 ) {
+                error("ftell() failed");
+        }
+
+        if ( fseek(file, 0, SEEK_END) != 0 ) {
+                error("fseek() failed");
+        }
+
+        long size = ftell(file);
+        if ( size == -1 ) {
+                error("ftell() failed");
+        }
+
+        if ( fseek(file, current_pos, SEEK_SET) != 0 ) {
+                error("fseek() failed");
+        }
+
+        return (size_t) size;
 }
 
 void
 do_compress(FILE *in_file, FILE *out_file, int compress_level)
 {
-        const unsigned long in_size = get_filesize(in_file);
+        size_t 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);
+        size_t         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);
+        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);
+                (void) fprintf(stderr, "Error: %s\n", zError(error));
         }
 
         free(out_data);
@@ -53,26 +77,32 @@ do_compress(FILE *in_file, FILE *out_file, int compress_level)
 void
 do_uncompress(FILE *in_file, FILE *out_file)
 {
-        const unsigned long in_size = get_filesize(in_file);
+        size_t 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;
+        size_t out_size = 0;
+        memcpy(&out_size, in_data, sizeof out_size);
+
         unsigned char *out_data = malloc(out_size);
 
-        unsigned long tmp = in_size - sizeof(unsigned long);
+        const size_t compressed_data_size = in_size - sizeof(size_t);
+        size_t       consumed_size        = compressed_data_size;
 
-        const int error = uncompress2(out_data,
-                                      &out_size,
-                                      in_data + sizeof(unsigned long),
-                                      &tmp);
+        const int error = uncompress2(out_data, &out_size,
+                                      in_data + sizeof(size_t),
+                                      &consumed_size);
 
         if ( !error ) {
+                if ( compressed_data_size != consumed_size ) {
+                        (void) fputs("Warning: Trailing data detected.\n", stderr);
+                }
+
                 (void) fwrite(out_data, 1, out_size, out_file);
         }
         else {
-                printf("Error: %d\n", error);
+                (void) fprintf(stderr, "Error: %s\n", zError(error));
         }
 
         free(out_data);
@@ -82,8 +112,13 @@ do_uncompress(FILE *in_file, FILE *out_file)
 int
 main(int argc, char *argv[])
 {
+        enum {
+                COMPRESSION_STD  = 5,
+                COMPRESSION_BEST = 9
+        };
+
         int decompress     = 0;
-        int compress_level = 5;
+        int compress_level = COMPRESSION_STD;
 
         int opt = 0;
         while ( (opt = getopt(argc, argv, "dl")) != -1 ) {
@@ -93,13 +128,13 @@ main(int argc, char *argv[])
                         break;
 
                 case 'l':
-                        compress_level = 9;
+                        compress_level = COMPRESSION_BEST;
                         break;
 
                 case '?':
                 default:
                         usage();
-                        break;
+                        return EXIT_SUCCESS;
                 }
         }
         argc -= optind;