diff --git a/Makefile.in b/Makefile.in
index 03dbbdf5..eae30653 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -118,6 +118,7 @@ C_SRCS := $(srcroot)src/jemalloc.c \
$(srcroot)src/extent.c \
$(srcroot)src/extent_dss.c \
$(srcroot)src/extent_mmap.c \
+ $(srcroot)src/fxp.c \
$(srcroot)src/hook.c \
$(srcroot)src/hpa.c \
$(srcroot)src/hpa_central.c \
@@ -212,6 +213,7 @@ TESTS_UNIT := \
$(srcroot)test/unit/extent_quantize.c \
${srcroot}test/unit/flat_bitmap.c \
$(srcroot)test/unit/fork.c \
+ ${srcroot}test/unit/fxp.c \
$(srcroot)test/unit/hash.c \
$(srcroot)test/unit/hook.c \
$(srcroot)test/unit/hpa.c \
diff --git a/include/jemalloc/internal/fxp.h b/include/jemalloc/internal/fxp.h
new file mode 100644
index 00000000..d9438090
--- /dev/null
+++ b/include/jemalloc/internal/fxp.h
@@ -0,0 +1,100 @@
+#ifndef JEMALLOC_INTERNAL_FXP_H
+#define JEMALLOC_INTERNAL_FXP_H
+
+/*
+ * A simple fixed-point math implementation, supporting only unsigned values
+ * (with overflow being an error).
+ *
+ * It's not in general safe to use floating point in core code, because various
+ * libc implementations we get linked against can assume that malloc won't touch
+ * floating point state and call it with an unusual calling convention.
+ */
+
+/*
+ * High 16 bits are the integer part, low 16 are the fractional part. Or
+ * equivalently, repr == 2**16 * val, where we use "val" to refer to the
+ * (imaginary) fractional representation of the true value.
+ *
+ * We pick a uint32_t here since it's convenient in some places to
+ * double the representation size (i.e. multiplication and division use
+ * 64-bit integer types), and a uint64_t is the largest type we're
+ * certain is available.
+ */
+typedef uint32_t fxp_t;
+#define FXP_INIT_INT(x) ((x) << 16)
+
+/*
+ * Amount of precision used in parsing and printing numbers. The integer bound
+ * is simply because the integer part of the number gets 16 bits, and so is
+ * bounded by 65536.
+ *
+ * We use a lot of precision for the fractional part, even though most of it
+ * gets rounded off; this lets us get exact values for the important special
+ * case where the denominator is a small power of 2 (for instance,
+ * 1/512 == 0.001953125 is exactly representable even with only 16 bits of
+ * fractional precision). We need to left-shift by 16 before dividing by
+ * 10**precision, so we pick precision to be floor(log(2**48)) = 14.
+ */
+#define FXP_INTEGER_PART_DIGITS 5
+#define FXP_FRACTIONAL_PART_DIGITS 14
+
+/*
+ * In addition to the integer and fractional parts of the number, we need to
+ * include a null character and (possibly) a decimal point.
+ */
+#define FXP_BUF_SIZE (FXP_INTEGER_PART_DIGITS + FXP_FRACTIONAL_PART_DIGITS + 2)
+
+static inline fxp_t
+fxp_add(fxp_t a, fxp_t b) {
+ return a + b;
+}
+
+static inline fxp_t
+fxp_sub(fxp_t a, fxp_t b) {
+ assert(a >= b);
+ return a - b;
+}
+
+static inline fxp_t
+fxp_mul(fxp_t a, fxp_t b) {
+ uint64_t unshifted = (uint64_t)a * (uint64_t)b;
+ /*
+ * Unshifted is (a.val * 2**16) * (b.val * 2**16)
+ * == (a.val * b.val) * 2**32, but we want
+ * (a.val * b.val) * 2 ** 16.
+ */
+ return (uint32_t)(unshifted >> 16);
+}
+
+static inline fxp_t
+fxp_div(fxp_t a, fxp_t b) {
+ assert(b != 0);
+ uint64_t unshifted = ((uint64_t)a << 32) / (uint64_t)b;
+ /*
+ * Unshifted is (a.val * 2**16) * (2**32) / (b.val * 2**16)
+ * == (a.val / b.val) * (2 ** 32), which again corresponds to a right
+ * shift of 16.
+ */
+ return (uint32_t)(unshifted >> 16);
+}
+
+static inline uint32_t
+fxp_round_down(fxp_t a) {
+ return a >> 16;
+}
+
+static inline uint32_t
+fxp_round_nearest(fxp_t a) {
+ uint32_t fractional_part = (a & ((1U << 16) - 1));
+ uint32_t increment = (uint32_t)(fractional_part >= (1U << 15));
+ return (a >> 16) + increment;
+}
+
+/*
+ * Returns true on error. Otherwise, returns false and updates *ptr to point to
+ * the first character not parsed (because it wasn't a digit).
+ */
+bool fxp_parse(fxp_t *a, const char *ptr, char **end);
+void fxp_print(fxp_t a, char buf[FXP_BUF_SIZE]);
+
+#endif /* JEMALLOC_INTERNAL_FXP_H */
diff --git a/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj b/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj
index 2d6b4b6e..6c4e7fdc 100644
--- a/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj
+++ b/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj
@@ -58,6 +58,7 @@
+
diff --git a/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj.filters b/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj.filters
index e3b7e0c5..84ff5748 100644
--- a/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj.filters
+++ b/msvc/projects/vc2015/jemalloc/jemalloc.vcxproj.filters
@@ -58,6 +58,9 @@
Source Files
+
+ Source Files
+
Source Files
diff --git a/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj b/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj
index 33d87a44..07fbe21e 100644
--- a/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj
+++ b/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj
@@ -58,6 +58,7 @@
+
diff --git a/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj.filters b/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj.filters
index e3b7e0c5..84ff5748 100644
--- a/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj.filters
+++ b/msvc/projects/vc2017/jemalloc/jemalloc.vcxproj.filters
@@ -58,6 +58,9 @@
Source Files
+
+ Source Files
+
Source Files
diff --git a/src/fxp.c b/src/fxp.c
new file mode 100644
index 00000000..96585f0a
--- /dev/null
+++ b/src/fxp.c
@@ -0,0 +1,124 @@
+#include "jemalloc/internal/jemalloc_preamble.h"
+#include "jemalloc/internal/jemalloc_internal_includes.h"
+
+#include "jemalloc/internal/fxp.h"
+
+static bool
+fxp_isdigit(char c) {
+ return '0' <= c && c <= '9';
+}
+
+bool
+fxp_parse(fxp_t *result, const char *str, char **end) {
+ /*
+ * Using malloc_strtoumax in this method isn't as handy as you might
+ * expect (I tried). In the fractional part, significant leading zeros
+ * mean that you still need to do your own parsing, now with trickier
+ * math. In the integer part, the casting (uintmax_t to uint32_t)
+ * forces more reasoning about bounds than just checking for overflow as
+ * we parse.
+ */
+ uint32_t integer_part = 0;
+
+ const char *cur = str;
+
+ /* The string must start with a digit or a decimal point. */
+ if (*cur != '.' && !fxp_isdigit(*cur)) {
+ return true;
+ }
+
+ while ('0' <= *cur && *cur <= '9') {
+ integer_part *= 10;
+ integer_part += *cur - '0';
+ if (integer_part >= (1U << 16)) {
+ return true;
+ }
+ cur++;
+ }
+
+ /*
+ * We've parsed all digits at the beginning of the string, without
+ * overflow. Either we're done, or there's a fractional part.
+ */
+ if (*cur != '.') {
+ *result = (integer_part << 16);
+ if (end != NULL) {
+ *end = (char *)cur;
+ }
+ return false;
+ }
+
+ /* There's a fractional part. */
+ cur++;
+ if (!fxp_isdigit(*cur)) {
+ /* Shouldn't end on the decimal point. */
+ return true;
+ }
+
+ /*
+ * We use a lot of precision for the fractional part, even though we'll
+ * discard most of it; this lets us get exact values for the important
+ * special case where the denominator is a small power of 2 (for
+ * instance, 1/512 == 0.001953125 is exactly representable even with
+ * only 16 bits of fractional precision). We need to left-shift by 16
+ * before dividing so we pick the number of digits to be
+ * floor(log(2**48)) = 14.
+ */
+ uint64_t fractional_part = 0;
+ uint64_t frac_div = 1;
+ for (int i = 0; i < FXP_FRACTIONAL_PART_DIGITS; i++) {
+ fractional_part *= 10;
+ frac_div *= 10;
+ if (fxp_isdigit(*cur)) {
+ fractional_part += *cur - '0';
+ cur++;
+ }
+ }
+ /*
+ * We only parse the first maxdigits characters, but we can still ignore
+ * any digits after that.
+ */
+ while (fxp_isdigit(*cur)) {
+ cur++;
+ }
+
+ assert(fractional_part < frac_div);
+ uint32_t fractional_repr = (uint32_t)(
+ (fractional_part << 16) / frac_div);
+
+ /* Success! */
+ *result = (integer_part << 16) + fractional_repr;
+ if (end != NULL) {
+ *end = (char *)cur;
+ }
+ return false;
+}
+
+void
+fxp_print(fxp_t a, char buf[FXP_BUF_SIZE]) {
+ uint32_t integer_part = fxp_round_down(a);
+ uint32_t fractional_part = (a & ((1U << 16) - 1));
+
+ int leading_fraction_zeros = 0;
+ uint64_t fraction_digits = fractional_part;
+ for (int i = 0; i < FXP_FRACTIONAL_PART_DIGITS; i++) {
+ if (fraction_digits < (1U << 16)
+ && fraction_digits * 10 >= (1U << 16)) {
+ leading_fraction_zeros = i;
+ }
+ fraction_digits *= 10;
+ }
+ fraction_digits >>= 16;
+ while (fraction_digits > 0 && fraction_digits % 10 == 0) {
+ fraction_digits /= 10;
+ }
+
+ size_t printed = malloc_snprintf(buf, FXP_BUF_SIZE, "%"FMTu32".",
+ integer_part);
+ for (int i = 0; i < leading_fraction_zeros; i++) {
+ buf[printed] = '0';
+ printed++;
+ }
+ malloc_snprintf(&buf[printed], FXP_BUF_SIZE - printed, "%"FMTu64,
+ fraction_digits);
+}
diff --git a/test/unit/fxp.c b/test/unit/fxp.c
new file mode 100644
index 00000000..89f0ca65
--- /dev/null
+++ b/test/unit/fxp.c
@@ -0,0 +1,344 @@
+#include "test/jemalloc_test.h"
+
+#include "jemalloc/internal/fxp.h"
+
+static double
+fxp2double(fxp_t a) {
+ double intpart = (double)(a >> 16);
+ double fracpart = (double)(a & ((1U << 16) - 1)) / (1U << 16);
+ return intpart + fracpart;
+}
+
+/* Is a close to b? */
+static bool
+double_close(double a, double b) {
+ /*
+ * Our implementation doesn't try for precision. Correspondingly, don't
+ * enforce it too strenuously here; accept values that are close in
+ * either relative or absolute terms.
+ */
+ return fabs(a - b) < 0.01 || fabs(a - b) / a < 0.01;
+}
+
+static bool
+fxp_close(fxp_t a, fxp_t b) {
+ return double_close(fxp2double(a), fxp2double(b));
+}
+
+static fxp_t
+xparse_fxp(const char *str) {
+ fxp_t result;
+ bool err = fxp_parse(&result, str, NULL);
+ assert_false(err, "Invalid fxp string: %s", str);
+ return result;
+}
+
+static void
+expect_parse_accurate(const char *str, const char *parse_str) {
+ double true_val = strtod(str, NULL);
+ fxp_t fxp_val;
+ char *end;
+ bool err = fxp_parse(&fxp_val, parse_str, &end);
+ expect_false(err, "Unexpected parse failure");
+ expect_ptr_eq(parse_str + strlen(str), end,
+ "Didn't parse whole string");
+ expect_true(double_close(fxp2double(fxp_val), true_val),
+ "Misparsed %s", str);
+}
+
+static void
+parse_valid_trial(const char *str) {
+ /* The value it parses should be correct. */
+ expect_parse_accurate(str, str);
+ char buf[100];
+ snprintf(buf, sizeof(buf), "%swith_some_trailing_text", str);
+ expect_parse_accurate(str, buf);
+ snprintf(buf, sizeof(buf), "%s with a space", str);
+ expect_parse_accurate(str, buf);
+ snprintf(buf, sizeof(buf), "%s,in_a_malloc_conf_string:1", str);
+ expect_parse_accurate(str, buf);
+}
+
+TEST_BEGIN(test_parse_valid) {
+ parse_valid_trial("0");
+ parse_valid_trial("1");
+ parse_valid_trial("2");
+ parse_valid_trial("100");
+ parse_valid_trial("345");
+ parse_valid_trial("00000000123");
+ parse_valid_trial("00000000987");
+
+ parse_valid_trial("0.0");
+ parse_valid_trial("0.00000000000456456456");
+ parse_valid_trial("100.00000000000456456456");
+
+ parse_valid_trial("123.1");
+ parse_valid_trial("123.01");
+ parse_valid_trial("123.001");
+ parse_valid_trial("123.0001");
+ parse_valid_trial("123.00001");
+ parse_valid_trial("123.000001");
+ parse_valid_trial("123.0000001");
+
+ parse_valid_trial(".0");
+ parse_valid_trial(".1");
+ parse_valid_trial(".01");
+ parse_valid_trial(".001");
+ parse_valid_trial(".0001");
+ parse_valid_trial(".00001");
+ parse_valid_trial(".000001");
+
+ parse_valid_trial(".1");
+ parse_valid_trial(".10");
+ parse_valid_trial(".100");
+ parse_valid_trial(".1000");
+ parse_valid_trial(".100000");
+}
+TEST_END
+
+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);
+ expect_true(err, "Expected a parse error on: %s", str);
+ expect_ptr_eq((void *)0x123, end,
+ "Parse error shouldn't change results");
+ expect_u32_eq(result, FXP_INIT_INT(333),
+ "Parse error shouldn't change results");
+}
+
+TEST_BEGIN(test_parse_invalid) {
+ expect_parse_failure("123.");
+ expect_parse_failure("3.a");
+ expect_parse_failure(".a");
+ expect_parse_failure("a.1");
+ expect_parse_failure("a");
+ /* A valid string, but one that overflows. */
+ expect_parse_failure("123456789");
+ expect_parse_failure("0000000123456789");
+ expect_parse_failure("1000000");
+}
+TEST_END
+
+static void
+expect_add(const char *astr, const char *bstr, const char* resultstr) {
+ fxp_t a = xparse_fxp(astr);
+ fxp_t b = xparse_fxp(bstr);
+ fxp_t result = xparse_fxp(resultstr);
+ expect_true(fxp_close(fxp_add(a, b), result),
+ "Expected %s + %s == %s", astr, bstr, resultstr);
+}
+
+TEST_BEGIN(test_add_simple) {
+ expect_add("0", "0", "0");
+ expect_add("0", "1", "1");
+ expect_add("1", "1", "2");
+ expect_add("1.5", "1.5", "3");
+ expect_add("0.1", "0.1", "0.2");
+ expect_add("123", "456", "579");
+}
+TEST_END
+
+static void
+expect_sub(const char *astr, const char *bstr, const char* resultstr) {
+ fxp_t a = xparse_fxp(astr);
+ fxp_t b = xparse_fxp(bstr);
+ fxp_t result = xparse_fxp(resultstr);
+ expect_true(fxp_close(fxp_sub(a, b), result),
+ "Expected %s - %s == %s", astr, bstr, resultstr);
+}
+
+TEST_BEGIN(test_sub_simple) {
+ expect_sub("0", "0", "0");
+ expect_sub("1", "0", "1");
+ expect_sub("1", "1", "0");
+ expect_sub("3.5", "1.5", "2");
+ expect_sub("0.3", "0.1", "0.2");
+ expect_sub("456", "123", "333");
+}
+TEST_END
+
+static void
+expect_mul(const char *astr, const char *bstr, const char* resultstr) {
+ fxp_t a = xparse_fxp(astr);
+ fxp_t b = xparse_fxp(bstr);
+ fxp_t result = xparse_fxp(resultstr);
+ expect_true(fxp_close(fxp_mul(a, b), result),
+ "Expected %s * %s == %s", astr, bstr, resultstr);
+}
+
+TEST_BEGIN(test_mul_simple) {
+ expect_mul("0", "0", "0");
+ expect_mul("1", "0", "0");
+ expect_mul("1", "1", "1");
+ expect_mul("1.5", "1.5", "2.25");
+ expect_mul("100.0", "10", "1000");
+ expect_mul(".1", "10", "1");
+}
+TEST_END
+
+static void
+expect_div(const char *astr, const char *bstr, const char* resultstr) {
+ fxp_t a = xparse_fxp(astr);
+ fxp_t b = xparse_fxp(bstr);
+ fxp_t result = xparse_fxp(resultstr);
+ expect_true(fxp_close(fxp_div(a, b), result),
+ "Expected %s / %s == %s", astr, bstr, resultstr);
+}
+
+TEST_BEGIN(test_div_simple) {
+ expect_div("1", "1", "1");
+ expect_div("0", "1", "0");
+ expect_div("2", "1", "2");
+ expect_div("3", "2", "1.5");
+ expect_div("3", "1.5", "2");
+ expect_div("10", ".1", "100");
+ expect_div("123", "456", ".2697368421");
+}
+TEST_END
+
+static void
+expect_round(const char *str, uint32_t rounded_down, uint32_t rounded_nearest) {
+ fxp_t fxp = xparse_fxp(str);
+ uint32_t fxp_rounded_down = fxp_round_down(fxp);
+ uint32_t fxp_rounded_nearest = fxp_round_nearest(fxp);
+ expect_u32_eq(rounded_down, fxp_rounded_down,
+ "Mistake rounding %s down", str);
+ expect_u32_eq(rounded_nearest, fxp_rounded_nearest,
+ "Mistake rounding %s to nearest", str);
+}
+
+TEST_BEGIN(test_round_simple) {
+ expect_round("1.5", 1, 2);
+ expect_round("0", 0, 0);
+ expect_round("0.1", 0, 0);
+ expect_round("0.4", 0, 0);
+ expect_round("0.40000", 0, 0);
+ expect_round("0.5", 0, 1);
+ expect_round("0.6", 0, 1);
+ expect_round("123", 123, 123);
+ expect_round("123.4", 123, 123);
+ expect_round("123.5", 123, 124);
+}
+TEST_END
+
+static void
+expect_print(const char *str) {
+ fxp_t fxp = xparse_fxp(str);
+ char buf[FXP_BUF_SIZE];
+ fxp_print(fxp, buf);
+ expect_d_eq(0, strcmp(str, buf), "Couldn't round-trip print %s", str);
+}
+
+TEST_BEGIN(test_print_simple) {
+ expect_print("0.0");
+ expect_print("1.0");
+ expect_print("2.0");
+ expect_print("123.0");
+ /*
+ * We hit the possibility of roundoff errors whenever the fractional
+ * component isn't a round binary number; only check these here (we
+ * round-trip properly in the stress test).
+ */
+ expect_print("1.5");
+ expect_print("3.375");
+ expect_print("0.25");
+ expect_print("0.125");
+ /* 1 / 2**14 */
+ expect_print("0.00006103515625");
+}
+TEST_END
+
+TEST_BEGIN(test_stress) {
+ const char *numbers[] = {
+ "0.0", "0.1", "0.2", "0.3", "0.4",
+ "0.5", "0.6", "0.7", "0.8", "0.9",
+
+ "1.0", "1.1", "1.2", "1.3", "1.4",
+ "1.5", "1.6", "1.7", "1.8", "1.9",
+
+ "2.0", "2.1", "2.2", "2.3", "2.4",
+ "2.5", "2.6", "2.7", "2.8", "2.9",
+
+ "17.0", "17.1", "17.2", "17.3", "17.4",
+ "17.5", "17.6", "17.7", "17.8", "17.9",
+
+ "18.0", "18.1", "18.2", "18.3", "18.4",
+ "18.5", "18.6", "18.7", "18.8", "18.9",
+
+ "123.0", "123.1", "123.2", "123.3", "123.4",
+ "123.5", "123.6", "123.7", "123.8", "123.9",
+
+ "124.0", "124.1", "124.2", "124.3", "124.4",
+ "124.5", "124.6", "124.7", "124.8", "124.9",
+
+ "125.0", "125.1", "125.2", "125.3", "125.4",
+ "125.5", "125.6", "125.7", "125.8", "125.9"};
+ size_t numbers_len = sizeof(numbers)/sizeof(numbers[0]);
+ for (size_t i = 0; i < numbers_len; i++) {
+ fxp_t fxp_a = xparse_fxp(numbers[i]);
+ double double_a = strtod(numbers[i], NULL);
+
+ uint32_t fxp_rounded_down = fxp_round_down(fxp_a);
+ uint32_t fxp_rounded_nearest = fxp_round_nearest(fxp_a);
+ uint32_t double_rounded_down = (uint32_t)double_a;
+ uint32_t double_rounded_nearest = (uint32_t)round(double_a);
+
+ expect_u32_eq(double_rounded_down, fxp_rounded_down,
+ "Incorrectly rounded down %s", numbers[i]);
+ expect_u32_eq(double_rounded_nearest, fxp_rounded_nearest,
+ "Incorrectly rounded-to-nearest %s", numbers[i]);
+
+ for (size_t j = 0; j < numbers_len; j++) {
+ fxp_t fxp_b = xparse_fxp(numbers[j]);
+ double double_b = strtod(numbers[j], NULL);
+
+ fxp_t fxp_sum = fxp_add(fxp_a, fxp_b);
+ double double_sum = double_a + double_b;
+ expect_true(
+ double_close(fxp2double(fxp_sum), double_sum),
+ "Miscomputed %s + %s", numbers[i], numbers[j]);
+
+ if (double_a > double_b) {
+ fxp_t fxp_diff = fxp_sub(fxp_a, fxp_b);
+ double double_diff = double_a - double_b;
+ expect_true(
+ double_close(fxp2double(fxp_diff),
+ double_diff),
+ "Miscomputed %s - %s", numbers[i],
+ numbers[j]);
+ }
+
+ fxp_t fxp_prod = fxp_mul(fxp_a, fxp_b);
+ double double_prod = double_a * double_b;
+ expect_true(
+ double_close(fxp2double(fxp_prod), double_prod),
+ "Miscomputed %s * %s", numbers[i], numbers[j]);
+
+ if (double_b != 0.0) {
+ fxp_t fxp_quot = fxp_div(fxp_a, fxp_b);
+ double double_quot = double_a / double_b;
+ expect_true(
+ double_close(fxp2double(fxp_quot),
+ double_quot),
+ "Miscomputed %s / %s", numbers[i],
+ numbers[j]);
+ }
+ }
+ }
+}
+TEST_END
+
+int
+main(void) {
+ return test_no_reentrancy(
+ test_parse_valid,
+ test_parse_invalid,
+ test_add_simple,
+ test_sub_simple,
+ test_mul_simple,
+ test_div_simple,
+ test_round_simple,
+ test_print_simple,
+ test_stress);
+}