From e1e0e9662d807b0323125ba65b72ba4fc5324f3a Mon Sep 17 00:00:00 2001
From: Rodrigo Arias <rodrigo.arias@bsc.es>
Date: Tue, 10 Jan 2023 14:50:49 +0100
Subject: [PATCH] Pack the value structure to be hashable

---
 src/emu/mux.c            |  7 ++-----
 src/emu/value.h          |  6 ++++--
 test/unit/CMakeLists.txt |  1 +
 test/unit/value.c        | 23 +++++++++++++++++++++++
 4 files changed, 30 insertions(+), 7 deletions(-)
 create mode 100644 test/unit/value.c

diff --git a/src/emu/mux.c b/src/emu/mux.c
index c6208ef..15c990c 100644
--- a/src/emu/mux.c
+++ b/src/emu/mux.c
@@ -157,11 +157,8 @@ struct mux_input *
 mux_find_input(struct mux *mux, struct value value)
 {
 	struct mux_input *input = NULL;
-	/* Only int64 due to garbage */
-	if (value.type != VALUE_INT64)
-		die("bad value type\n");
 
-	HASH_FIND(hh, mux->input, &value.i, sizeof(value.i), input);
+	HASH_FIND(hh, mux->input, &value, sizeof(value), input);
 	return input;
 }
 
@@ -185,7 +182,7 @@ mux_add_input(struct mux *mux, struct value key, struct chan *chan)
 	input->key = key;
 	input->chan = chan;
 
-	HASH_ADD_KEYPTR(hh, mux->input, &input->key.i, sizeof(input->key.i), input);
+	HASH_ADD_KEYPTR(hh, mux->input, &input->key, sizeof(input->key), input);
 
 	if (bay_add_cb(mux->bay, chan, cb_input, mux) != 0) {
 		err("mux_add_input: bay_add_cb failed\n");
diff --git a/src/emu/value.h b/src/emu/value.h
index d620968..05b9e6a 100644
--- a/src/emu/value.h
+++ b/src/emu/value.h
@@ -12,7 +12,9 @@ enum value_type {
 	VALUE_DOUBLE
 };
 
-struct value {
+/* Packed allows the struct to be hashable, as we don't have any
+ * unitialized data */
+struct __attribute__((packed)) value {
 	enum value_type type;
 	union {
 		int64_t i;
@@ -44,7 +46,7 @@ value_int64(int64_t i)
 static inline struct value
 value_null(void)
 {
-	struct value v = { .type = VALUE_NULL };
+	struct value v = { .type = VALUE_NULL, .i = 0 };
 	return v;
 }
 
diff --git a/test/unit/CMakeLists.txt b/test/unit/CMakeLists.txt
index 3bedb95..75aa0a7 100644
--- a/test/unit/CMakeLists.txt
+++ b/test/unit/CMakeLists.txt
@@ -11,3 +11,4 @@
 unit_test(chan.c)
 unit_test(bay.c)
 unit_test(mux.c)
+unit_test(value.c)
diff --git a/test/unit/value.c b/test/unit/value.c
new file mode 100644
index 0000000..b2e650a
--- /dev/null
+++ b/test/unit/value.c
@@ -0,0 +1,23 @@
+#include "emu/value.h"
+#include "common.h"
+
+int
+main(void)
+{
+	struct value a, b;
+
+	memset(&a, 66, sizeof(struct value));
+	memset(&b, 0, sizeof(struct value));
+
+	a = value_null();
+
+	/* Ensure we can use the whole size of the value struct to
+	 * compare two values, so we don't have problems with
+	 * unitialized holes due to alignment */
+	if (memcmp(&a, &b, sizeof(struct value)) != 0)
+		die("values are not the same\n");
+
+	err("OK\n");
+
+	return 0;
+}