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[njs] Fixed njs_number_to_int32() for big-endian platforms.

Dmitry Volyntsev
July 14, 2020 09:18AM
details: https://hg.nginx.org/njs/rev/c1f74ea54f89
branches:
changeset: 1465:c1f74ea54f89
user: Dmitry Volyntsev <xeioex@nginx.com>
date: Tue Jul 14 13:16:05 2020 +0000
description:
Fixed njs_number_to_int32() for big-endian platforms.

This is related to #326 issue in Github.

diffstat:

auto/clang | 17 -------------
src/njs_number.h | 73 ++++++++++++++++++++++++++++---------------------------
2 files changed, 37 insertions(+), 53 deletions(-)

diffs (135 lines):

diff -r 022995046310 -r c1f74ea54f89 auto/clang
--- a/auto/clang Tue Jul 14 14:49:46 2020 +0300
+++ b/auto/clang Tue Jul 14 13:16:05 2020 +0000
@@ -162,23 +162,6 @@ njs_feature_test="#include <sanitizer/ms
. auto/feature


-njs_feature="NAN to uint conversion"
-njs_feature_name=NJS_NAN_TO_UINT_CONVERSION
-njs_feature_run=value
-njs_feature_incs=
-njs_feature_libs=-lm
-njs_feature_test="#include <math.h>
- #include <stdio.h>
- #include <stdint.h>
-
- int main(void) {
- int64_t i64 = acosh(0);
- printf(\"%x\", (uint32_t) i64);
- return 0;
- }"
-. auto/feature
-
-
njs_feature="_mm_setcsr()"
njs_feature_name=NJS_HAVE_DENORMALS_CONTROL
njs_feature_run=no
diff -r 022995046310 -r c1f74ea54f89 src/njs_number.h
--- a/src/njs_number.h Tue Jul 14 14:49:46 2020 +0300
+++ b/src/njs_number.h Tue Jul 14 13:16:05 2020 +0000
@@ -52,38 +52,6 @@ njs_key_is_integer_index(double num, con


njs_inline int64_t
-njs_number_to_int64(double num)
-{
-#if (NJS_NAN_TO_UINT_CONVERSION != 0)
- /*
- * PPC32: NaN and Inf are converted to 0x8000000080000000
- * and become non-zero after truncation.
- */
-
- if (isnan(num) || isinf(num)) {
- return 0;
- }
-#endif
-
- /*
- * ES5.1: integer must be modulo 2^32.
- * 2^53 is the largest integer number which can be stored safely
- * in the IEEE-754 format and numbers less than 2^53 can be just
- * converted to int64_t eliding more expensive fmod() operation.
- * Then the int64 integer is truncated to uint32_t. The NaN is
- * converted to 0x8000000000000000 and becomes 0 after truncation.
- * fmod() of the Infinity returns NaN.
- */
-
- if (fabs(num) > 9007199254740992.0) {
- return (int64_t) fmod(num, 4294967296.0);
- }
-
- return (int64_t) num;
-}
-
-
-njs_inline int64_t
njs_number_to_integer(double num)
{
if (njs_slow_path(isinf(num))) {
@@ -97,28 +65,61 @@ njs_number_to_integer(double num)
return 0;
}

- return njs_number_to_int64(num);
+ return trunc(num) + 0.0;
}


njs_inline int32_t
njs_number_to_int32(double num)
{
- return (int32_t) njs_number_to_int64(num);
+ int32_t r;
+ uint64_t v;
+ njs_int_t exp;
+ njs_diyfp_conv_t conv;
+
+ conv.d = num;
+
+ exp = (conv.u64 & NJS_DBL_EXPONENT_MASK) >> NJS_DBL_SIGNIFICAND_SIZE;
+
+ if (njs_fast_path(exp < (NJS_DBL_EXPONENT_OFFSET + 30))) {
+ /* |num| < 2**31. */
+ return num;
+ }
+
+ if (exp < (NJS_DBL_EXPONENT_OFFSET + 30 + 53)) {
+ v = (conv.u64 & NJS_DBL_SIGNIFICAND_MASK) | NJS_DBL_HIDDEN_BIT;
+ v <<= (exp - NJS_DBL_EXPONENT_BIAS + 32);
+ r = v >> 32;
+
+ if (conv.u64 & NJS_DBL_SIGN_MASK) {
+ r = -r;
+ }
+
+ return r;
+ }
+
+ /*
+ * ES5.1: integer must be modulo 2^32.
+ * The distance between larger doubles
+ * (exp >= NJS_DBL_EXPONENT_OFFSET + 30 + 53) is a multiple of 2**32 => 0.
+ * This also handles NaN and Inf.
+ */
+
+ return 0;
}


njs_inline uint32_t
njs_number_to_uint32(double num)
{
- return (uint32_t) njs_number_to_int64(num);
+ return (uint32_t) njs_number_to_int32(num);
}


njs_inline uint16_t
njs_number_to_uint16(double num)
{
- return (uint16_t) njs_number_to_int64(num);
+ return (uint16_t) njs_number_to_int32(num);
}


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[njs] Fixed njs_number_to_int32() for big-endian platforms.

Dmitry Volyntsev 86 July 14, 2020 09:18AM



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