109 lines
4.3 KiB
Diff
109 lines
4.3 KiB
Diff
From 23d76d88630ecee02515e2c8f5c8769cc795ae23 Mon Sep 17 00:00:00 2001
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From: Shane Carr <shane@unicode.org>
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Date: Fri, 23 Mar 2018 00:56:16 +0000
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Subject: [PATCH] ICU-13634 Adding integer overflow logic to ICU4C number
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pipeline in places where it is in ICU4J.
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X-SVN-Rev: 41136
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diff --git a/icu4c/source/common/putil.cpp b/icu4c/source/common/putil.cpp
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index 83f08ac070..452e2fd79c 100644
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--- a/icu4c/source/common/putil.cpp
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+++ b/icu4c/source/common/putil.cpp
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@@ -533,6 +533,30 @@ uprv_fmin(double x, double y)
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return (x > y ? y : x);
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}
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+#include <iostream>
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+
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+U_CAPI UBool U_EXPORT2
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+uprv_add32_overflow(int32_t a, int32_t b, int32_t* res) {
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+ // NOTE: Some compilers (GCC, Clang) have primitives available, like __builtin_add_overflow.
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+ // This function could be optimized by calling one of those primitives.
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+ auto a64 = static_cast<int64_t>(a);
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+ auto b64 = static_cast<int64_t>(b);
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+ int64_t res64 = a64 + b64;
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+ *res = static_cast<int32_t>(res64);
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+ return res64 != *res;
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+}
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+
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+U_CAPI UBool U_EXPORT2
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+uprv_mul32_overflow(int32_t a, int32_t b, int32_t* res) {
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+ // NOTE: Some compilers (GCC, Clang) have primitives available, like __builtin_mul_overflow.
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+ // This function could be optimized by calling one of those primitives.
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+ auto a64 = static_cast<int64_t>(a);
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+ auto b64 = static_cast<int64_t>(b);
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+ int64_t res64 = a64 * b64;
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+ *res = static_cast<int32_t>(res64);
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+ return res64 != *res;
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+}
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+
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/**
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* Truncates the given double.
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* trunc(3.3) = 3.0, trunc (-3.3) = -3.0
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diff --git a/icu4c/source/common/putilimp.h b/icu4c/source/common/putilimp.h
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index eb9b5380f1..8b858df9e3 100644
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--- a/icu4c/source/common/putilimp.h
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+++ b/icu4c/source/common/putilimp.h
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@@ -391,6 +391,32 @@ U_INTERNAL double U_EXPORT2 uprv_log(double d);
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*/
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U_INTERNAL double U_EXPORT2 uprv_round(double x);
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+/**
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+ * Adds the signed integers a and b, storing the result in res.
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+ * Checks for signed integer overflow.
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+ * Similar to the GCC/Clang extension __builtin_add_overflow
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+ *
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+ * @param a The first operand.
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+ * @param b The second operand.
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+ * @param res a + b
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+ * @return true if overflow occurred; false if no overflow occurred.
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+ * @internal
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+ */
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+U_INTERNAL UBool U_EXPORT2 uprv_add32_overflow(int32_t a, int32_t b, int32_t* res);
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+
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+/**
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+ * Multiplies the signed integers a and b, storing the result in res.
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+ * Checks for signed integer overflow.
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+ * Similar to the GCC/Clang extension __builtin_mul_overflow
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+ *
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+ * @param a The first multiplicand.
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+ * @param b The second multiplicand.
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+ * @param res a * b
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+ * @return true if overflow occurred; false if no overflow occurred.
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+ * @internal
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+ */
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+U_INTERNAL UBool U_EXPORT2 uprv_mul32_overflow(int32_t a, int32_t b, int32_t* res);
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+
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#if 0
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/**
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* Returns the number of digits after the decimal point in a double number x.
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diff --git a/icu4c/source/test/cintltst/putiltst.c b/icu4c/source/test/cintltst/putiltst.c
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index b99d9fca9c..1c3e073041 100644
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--- a/icu4c/source/test/cintltst/putiltst.c
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+++ b/icu4c/source/test/cintltst/putiltst.c
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@@ -128,6 +128,20 @@ static void TestPUtilAPI(void){
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log_err("ERROR: uprv_isInfinite failed.\n");
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}
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+ log_verbose("Testing the APIs uprv_add32_overflow and uprv_mul32_overflow\n");
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+ int32_t overflow_result;
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+ doAssert(FALSE, uprv_add32_overflow(INT32_MAX - 2, 1, &overflow_result), "should not overflow");
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+ doAssert(INT32_MAX - 1, overflow_result, "should equal INT32_MAX - 1");
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+ doAssert(FALSE, uprv_add32_overflow(INT32_MAX - 2, 2, &overflow_result), "should not overflow");
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+ doAssert(INT32_MAX, overflow_result, "should equal exactly INT32_MAX");
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+ doAssert(TRUE, uprv_add32_overflow(INT32_MAX - 2, 3, &overflow_result), "should overflow");
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+ doAssert(FALSE, uprv_mul32_overflow(INT32_MAX / 5, 4, &overflow_result), "should not overflow");
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+ doAssert(INT32_MAX / 5 * 4, overflow_result, "should equal INT32_MAX / 5 * 4");
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+ doAssert(TRUE, uprv_mul32_overflow(INT32_MAX / 5, 6, &overflow_result), "should overflow");
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+ // Test on negative numbers:
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+ doAssert(FALSE, uprv_add32_overflow(-3, -2, &overflow_result), "should not overflow");
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+ doAssert(-5, overflow_result, "should equal -5");
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+
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#if 0
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log_verbose("Testing the API uprv_digitsAfterDecimal()....\n");
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doAssert(uprv_digitsAfterDecimal(value1), 3, "uprv_digitsAfterDecimal() failed.");
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--
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2.24.1
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