fileio: add READ_FULL_FILE_UNHEX flag

Similar to READ_FULL_FILE_UNBASE64, read data is decoded with
unhexmem().

src/basic/fileio.c

@@ -279,7 +279,8 @@ int read_full_stream_full(
 
         assert(f);
         assert(ret_contents);
-        assert(!(flags & READ_FULL_FILE_UNBASE64) || ret_size);
+        assert(!FLAGS_SET(flags, READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX));
+        assert(!(flags & (READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX)) || ret_size);
 
         n_next = LINE_MAX; /* Start size */
 
@@ -356,9 +357,12 @@ int read_full_stream_full(
                 n_next = MIN(n * 2, READ_FULL_BYTES_MAX);
         }
 
-        if (flags & READ_FULL_FILE_UNBASE64) {
+        if (flags & (READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX)) {
                 buf[l++] = 0;
-                r = unbase64mem_full(buf, l, flags & READ_FULL_FILE_SECURE, (void **) ret_contents, ret_size);
+                if (flags & READ_FULL_FILE_UNBASE64)
+                        r = unbase64mem_full(buf, l, flags & READ_FULL_FILE_SECURE, (void **) ret_contents, ret_size);
+                else
+                        r = unhexmem_full(buf, l, flags & READ_FULL_FILE_SECURE, (void **) ret_contents, ret_size);
                 goto finalize;
         }
 

src/basic/fileio.h

@@ -31,6 +31,7 @@ typedef enum {
 typedef enum {
         READ_FULL_FILE_SECURE   = 1 << 0,
         READ_FULL_FILE_UNBASE64 = 1 << 1,
+        READ_FULL_FILE_UNHEX    = 1 << 2,
 } ReadFullFileFlags;
 
 int write_string_stream_ts(FILE *f, const char *line, WriteStringFileFlags flags, struct timespec *ts);