refuse to compress directories

fix #1211, reported by @imba-tjd

2 files changed, 34 insertions, 12 deletions

diff --git a/programs/lz4io.c b/programs/lz4io.c
index 8b70b91..09d906e 100644
--- a/programs/lz4io.c
+++ b/programs/lz4io.c
@@ -325,11 +325,16 @@ static FILE* LZ4IO_openSrcFile(const char* srcFileName)
         DISPLAYLEVEL(4,"Using stdin for input \n");
         f = stdin;
         SET_BINARY_MODE(stdin);
-    } else {
-        f = fopen(srcFileName, "rb");
-        if (f==NULL) DISPLAYLEVEL(1, "%s: %s \n", srcFileName, strerror(errno));
+        return f;
+    }
+
+    if (UTIL_isDir(srcFileName)) {
+        DISPLAYLEVEL(1, "lz4: %s is a directory -- ignored \n", srcFileName);
+        return NULL;
     }
 
+    f = fopen(srcFileName, "rb");
+    if (f==NULL) DISPLAYLEVEL(1, "%s: %s \n", srcFileName, strerror(errno));
     return f;
 }
 
@@ -337,7 +342,8 @@ static FILE* LZ4IO_openSrcFile(const char* srcFileName)
  *  prefs is writable, because sparseFileSupport might be updated.
  *  condition : `dstFileName` must be non-NULL.
  * @result : FILE* to `dstFileName`, or NULL if it fails */
-static FILE* LZ4IO_openDstFile(const char* dstFileName, const LZ4IO_prefs_t* const prefs)
+static FILE*
+LZ4IO_openDstFile(const char* dstFileName, const LZ4IO_prefs_t* const prefs)
 {
     FILE* f;
     assert(dstFileName != NULL);
@@ -563,11 +569,14 @@ static void* LZ4IO_createDict(size_t* dictSize, const char* const dictFilename)
     char*  dictBuf;
     FILE* dictFile;
 
-    if (!circularBuf) END_PROCESS(25, "Allocation error : not enough memory for circular buffer");
-    if (!dictFilename) END_PROCESS(26, "Dictionary error : no filename provided");
+    if (!dictFilename)
+        END_PROCESS(26, "Dictionary error : no filename provided");
+    if (!circularBuf)
+        END_PROCESS(25, "Allocation error : not enough memory for circular buffer");
 
     dictFile = LZ4IO_openSrcFile(dictFilename);
-    if (!dictFile) END_PROCESS(27, "Dictionary error : could not open dictionary file");
+    if (!dictFile)
+        END_PROCESS(27, "Dictionary error : could not open dictionary file");
 
     /* opportunistically seek to the part of the file we care about.
      * If this fails it's not a problem since we'll just read everything anyways. */
@@ -1311,7 +1320,8 @@ LZ4IO_decompressSrcFile(dRess_t ress,
 
 static int
 LZ4IO_decompressDstFile(dRess_t ress,
-                        const char* input_filename, const char* output_filename,
+                        const char* input_filename,
+                        const char* output_filename,
                         const LZ4IO_prefs_t* const prefs)
 {
     int result;
diff --git a/programs/util.h b/programs/util.h
index 3192ddc..f1d8a92 100644
--- a/programs/util.h
+++ b/programs/util.h
@@ -195,10 +195,7 @@ UTIL_STATIC void* UTIL_realloc(void* ptr, size_t size)
 /*-****************************************
 *  String functions
 ******************************************/
-/*
- * A modified version of realloc().
- * If UTIL_realloc() fails the original block is freed.
-*/
+/* supports a==NULL or b==NULL */
 UTIL_STATIC int UTIL_sameString(const char* a, const char* b)
 {
     assert(a!=NULL && b!=NULL);  /* unsupported scenario */
@@ -430,6 +427,21 @@ UTIL_STATIC int UTIL_isRegFile(const char* infilename)
     return UTIL_getFileStat(infilename, &statbuf); /* Only need to know whether it is a regular file */
 }
 
+UTIL_STATIC int UTIL_isDir(const char* infilename)
+{
+    stat_t statbuf;
+    int r;
+#if defined(_MSC_VER)
+    r = _stat64(infilename, &statbuf);
+    if (r) return 0;
+    return (statbuf.st_mode & S_IFDIR);
+#else
+    r = stat(infilename, &statbuf);
+    if (r) return 0;
+    return (S_ISDIR(statbuf.st_mode));
+#endif
+}
+
 
 UTIL_STATIC U32 UTIL_isDirectory(const char* infilename)
 {