From bdb7307ff28cdee92861a32ecae16919cc9af614 Mon Sep 17 00:00:00 2001
From: David Goldblatt <davidgoldblatt@fb.com>
Date: Tue, 8 Dec 2020 15:28:28 -0800
Subject: [PATCH] fxp: Add FXP_INIT_PERCENT

This lets us specify fxp values easily in source.
---
 include/jemalloc/internal/fxp.h |  1 +
 test/unit/fxp.c                 | 27 ++++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/include/jemalloc/internal/fxp.h b/include/jemalloc/internal/fxp.h
index b9803a63..415a9828 100644
--- a/include/jemalloc/internal/fxp.h
+++ b/include/jemalloc/internal/fxp.h
@@ -22,6 +22,7 @@
  */
 typedef uint32_t fxp_t;
 #define FXP_INIT_INT(x) ((x) << 16)
+#define FXP_INIT_PERCENT(pct) (((pct) << 16) / 100)
 
 /*
  * Amount of precision used in parsing and printing numbers.  The integer bound
diff --git a/test/unit/fxp.c b/test/unit/fxp.c
index 0fe5d67a..27f10976 100644
--- a/test/unit/fxp.c
+++ b/test/unit/fxp.c
@@ -96,7 +96,8 @@ TEST_BEGIN(test_parse_valid) {
 }
 TEST_END
 
-static void expect_parse_failure(const char *str) {
+static void
+expect_parse_failure(const char *str) {
 	fxp_t result = FXP_INIT_INT(333);
 	char *end = (void *)0x123;
 	bool err = fxp_parse(&result, str, &end);
@@ -120,6 +121,29 @@ TEST_BEGIN(test_parse_invalid) {
 }
 TEST_END
 
+static void
+expect_init_percent(unsigned percent, const char *str) {
+	fxp_t result_init = FXP_INIT_PERCENT(percent);
+	fxp_t result_parse = xparse_fxp(str);
+	expect_u32_eq(result_init, result_parse,
+	    "Expect representations of FXP_INIT_PERCENT(%u) and "
+	    "fxp_parse(\"%s\") to be equal; got %x and %x",
+	    percent, str, result_init, result_parse);
+
+}
+
+/*
+ * Every other test uses either parsing or FXP_INIT_INT; it gets tested in those
+ * ways.  We need a one-off for the percent-based initialization, though.
+ */
+TEST_BEGIN(test_init_percent) {
+	expect_init_percent(100, "1");
+	expect_init_percent(75, ".75");
+	expect_init_percent(1, ".01");
+	expect_init_percent(50, ".5");
+}
+TEST_END
+
 static void
 expect_add(const char *astr, const char *bstr, const char* resultstr) {
 	fxp_t a = xparse_fxp(astr);
@@ -358,6 +382,7 @@ main(void) {
 	return test_no_reentrancy(
 	    test_parse_valid,
 	    test_parse_invalid,
+	    test_init_percent,
 	    test_add_simple,
 	    test_sub_simple,
 	    test_mul_simple,