cfspack: add the ability to spit a single file

tools/cfspack/README.md

@@ -15,6 +15,9 @@ to the filenames under it.
 `cfspack` takes an optional second argument, a "fnmatch" pattern. If specified,
 only files patching the pattern will be included.
 
+If path is a file, a CFS with a single file will be spit and its name will
+exclude the directory part of that filename.
+
 The program errors out if a file name is too long (> 26 bytes) or too big
 (> 0x10000 - 0x20 bytes).
 

tools/cfspack/cfspack.c

@@ -3,12 +3,20 @@
 #include <dirent.h>
 #include <string.h>
 #include <fnmatch.h>
+#include <sys/stat.h>
 
 #define BLKSIZE 0x100
 #define HEADERSIZE 0x20
 #define MAX_FN_LEN 25   // 26 - null char
 #define MAX_FILE_SIZE (BLKSIZE * 0x100) - HEADERSIZE
 
+int is_regular_file(char *path)
+{
+    struct stat path_stat;
+    stat(path, &path_stat);
+    return S_ISREG(path_stat.st_mode);
+}
+
 int spitblock(char *fullpath, char *fn)
 {
     FILE *fp = fopen(fullpath, "r");
@@ -124,6 +132,11 @@ int main(int argc, char *argv[])
     if (argc == 3) {
         pattern = argv[2];
     }
-    return spitdir(srcpath, "", pattern);
+    if (is_regular_file(srcpath)) {
+        // special case: just one file
+        return spitblock(srcpath, basename(srcpath));
+    } else {
+        return spitdir(srcpath, "", pattern);
+    }
 }