add temporary file name generator

src/image.zig

@@ -37,6 +37,37 @@ fn sopen(
     return file.?;
 }
 
+fn temporaryName(allocator: *std.mem.Allocator) ![]u8 {
+    const template_start = "/temp/temp_";
+    const template = "/tmp/temp_XXXXXX";
+    var nam = try allocator.alloc(u8, template.len);
+    std.mem.copy(u8, nam, template);
+
+    var r = std.rand.DefaultPrng.init(std.time.timestamp());
+
+    var fill = nam[template_start.len..nam.len];
+
+    var i: usize = 0;
+    while (i < 100) : (i += 1) {
+
+        // generate a random uppercase letter, that is, 65 + random number.
+        for (fill) |_, f_idx| {
+            var idx = @intCast(u8, r.random.uintLessThan(u5, 24));
+            var letter = u8(65) + idx;
+            fill[f_idx] = letter;
+        }
+
+        // if we fail to access it, we assume it doesn't exist and return it.
+        std.fs.File.access(nam) catch |err| {
+            if (err == error.FileNotFound) {
+                return nam;
+            }
+        };
+    }
+
+    return error.TempGenFail;
+}
+
 pub const Image = struct {
     allocator: *std.mem.Allocator,
     sndfile: *c.SNDFILE,
@@ -92,6 +123,10 @@ pub const Image = struct {
         return n_read == 1;
     }
 
+    /// Run a plugin over the image.
+    /// This setups a new lilv world/plugin among other things.
+    /// The internal SNDFILE pointer is modified to point to the output of the
+    /// plugin run.
     pub fn runPlugin(
         self: *Image,
         plugin_uri: []const u8,
@@ -134,5 +169,10 @@ pub const Image = struct {
             );
             ports[idx].value = param.value;
         }
+
+        // now we need to generate a temporary file and put the output of
+        // running the plugin on that file
+        var tmpnam = try temporaryName(self.allocator);
+        std.debug.warn("temporary name: {}\n", tmpnam);
     }
 };