1 files changed, 266 insertions, 0 deletions
diff --git a/intl/icu/source/i18n/number_utils.cpp b/intl/icu/source/i18n/number_utils.cpp
new file mode 100644
index 0000000000..91d7f335cd
--- /dev/null
+++ b/intl/icu/source/i18n/number_utils.cpp
@@ -0,0 +1,266 @@
+// © 2018 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_FORMATTING
+
+// Allow implicit conversion from char16_t* to UnicodeString for this file:
+// Helpful in toString methods and elsewhere.
+#define UNISTR_FROM_STRING_EXPLICIT
+
+#include <stdlib.h>
+#include <cmath>
+#include "number_decnum.h"
+#include "number_types.h"
+#include "number_utils.h"
+#include "charstr.h"
+#include "decContext.h"
+#include "decNumber.h"
+#include "double-conversion.h"
+#include "fphdlimp.h"
+#include "uresimp.h"
+#include "ureslocs.h"
+
+using namespace icu;
+using namespace icu::number;
+using namespace icu::number::impl;
+
+using icu::double_conversion::DoubleToStringConverter;
+
+
+namespace {
+
+const char16_t*
+doGetPattern(UResourceBundle* res, const char* nsName, const char* patternKey, UErrorCode& publicStatus,
+             UErrorCode& localStatus) {
+    // Construct the path into the resource bundle
+    CharString key;
+    key.append("NumberElements/", publicStatus);
+    key.append(nsName, publicStatus);
+    key.append("/patterns/", publicStatus);
+    key.append(patternKey, publicStatus);
+    if (U_FAILURE(publicStatus)) {
+        return u"";
+    }
+    return ures_getStringByKeyWithFallback(res, key.data(), nullptr, &localStatus);
+}
+
+}
+
+
+const char16_t* utils::getPatternForStyle(const Locale& locale, const char* nsName, CldrPatternStyle style,
+                                          UErrorCode& status) {
+    const char* patternKey;
+    switch (style) {
+        case CLDR_PATTERN_STYLE_DECIMAL:
+            patternKey = "decimalFormat";
+            break;
+        case CLDR_PATTERN_STYLE_CURRENCY:
+            patternKey = "currencyFormat";
+            break;
+        case CLDR_PATTERN_STYLE_ACCOUNTING:
+            patternKey = "accountingFormat";
+            break;
+        case CLDR_PATTERN_STYLE_PERCENT:
+            patternKey = "percentFormat";
+            break;
+        case CLDR_PATTERN_STYLE_SCIENTIFIC:
+            patternKey = "scientificFormat";
+            break;
+        default:
+            patternKey = "decimalFormat"; // silence compiler error
+            UPRV_UNREACHABLE;
+    }
+    LocalUResourceBundlePointer res(ures_open(nullptr, locale.getName(), &status));
+    if (U_FAILURE(status)) { return u""; }
+
+    // Attempt to get the pattern with the native numbering system.
+    UErrorCode localStatus = U_ZERO_ERROR;
+    const char16_t* pattern;
+    pattern = doGetPattern(res.getAlias(), nsName, patternKey, status, localStatus);
+    if (U_FAILURE(status)) { return u""; }
+
+    // Fall back to latn if native numbering system does not have the right pattern
+    if (U_FAILURE(localStatus) && uprv_strcmp("latn", nsName) != 0) {
+        localStatus = U_ZERO_ERROR;
+        pattern = doGetPattern(res.getAlias(), "latn", patternKey, status, localStatus);
+        if (U_FAILURE(status)) { return u""; }
+    }
+
+    return pattern;
+}
+
+
+DecNum::DecNum() {
+    uprv_decContextDefault(&fContext, DEC_INIT_BASE);
+    uprv_decContextSetRounding(&fContext, DEC_ROUND_HALF_EVEN);
+    fContext.traps = 0; // no traps, thank you (what does this even mean?)
+}
+
+DecNum::DecNum(const DecNum& other, UErrorCode& status)
+        : fContext(other.fContext) {
+    // Allocate memory for the new DecNum.
+    U_ASSERT(fContext.digits == other.fData.getCapacity());
+    if (fContext.digits > kDefaultDigits) {
+        void* p = fData.resize(fContext.digits, 0);
+        if (p == nullptr) {
+            status = U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+    }
+
+    // Copy the data from the old DecNum to the new one.
+    uprv_memcpy(fData.getAlias(), other.fData.getAlias(), sizeof(decNumber));
+    uprv_memcpy(fData.getArrayStart(),
+            other.fData.getArrayStart(),
+            other.fData.getArrayLimit() - other.fData.getArrayStart());
+}
+
+void DecNum::setTo(StringPiece str, UErrorCode& status) {
+    // We need NUL-terminated for decNumber; CharString guarantees this, but not StringPiece.
+    CharString cstr(str, status);
+    if (U_FAILURE(status)) { return; }
+    _setTo(cstr.data(), str.length(), status);
+}
+
+void DecNum::setTo(const char* str, UErrorCode& status) {
+    _setTo(str, static_cast<int32_t>(uprv_strlen(str)), status);
+}
+
+void DecNum::setTo(double d, UErrorCode& status) {
+    // Need to check for NaN and Infinity before going into DoubleToStringConverter
+    if (std::isnan(d) != 0 || std::isfinite(d) == 0) {
+        status = U_UNSUPPORTED_ERROR;
+        return;
+    }
+
+    // First convert from double to string, then string to DecNum.
+    // Allocate enough room for: all digits, "E-324", and NUL-terminator.
+    char buffer[DoubleToStringConverter::kBase10MaximalLength + 6];
+    bool sign; // unused; always positive
+    int32_t length;
+    int32_t point;
+    DoubleToStringConverter::DoubleToAscii(
+            d,
+            DoubleToStringConverter::DtoaMode::SHORTEST,
+            0,
+            buffer,
+            sizeof(buffer),
+            &sign,
+            &length,
+            &point
+    );
+
+    // Read initial result as a string.
+    _setTo(buffer, length, status);
+
+    // Set exponent and bitmask. Note that DoubleToStringConverter does not do negatives.
+    fData.getAlias()->exponent += point - length;
+    fData.getAlias()->bits |= static_cast<uint8_t>(std::signbit(d) ? DECNEG : 0);
+}
+
+void DecNum::_setTo(const char* str, int32_t maxDigits, UErrorCode& status) {
+    if (maxDigits > kDefaultDigits) {
+        fData.resize(maxDigits, 0);
+        fContext.digits = maxDigits;
+    } else {
+        fContext.digits = kDefaultDigits;
+    }
+
+    static_assert(DECDPUN == 1, "Assumes that DECDPUN is set to 1");
+    uprv_decNumberFromString(fData.getAlias(), str, &fContext);
+
+    // Check for invalid syntax and set the corresponding error code.
+    if ((fContext.status & DEC_Conversion_syntax) != 0) {
+        status = U_DECIMAL_NUMBER_SYNTAX_ERROR;
+        return;
+    } else if (fContext.status != 0) {
+        // Not a syntax error, but some other error, like an exponent that is too large.
+        status = U_UNSUPPORTED_ERROR;
+        return;
+    }
+
+    // For consistency with Java BigDecimal, no support for DecNum that is NaN or Infinity!
+    if (decNumberIsSpecial(fData.getAlias())) {
+        status = U_UNSUPPORTED_ERROR;
+        return;
+    }
+}
+
+void
+DecNum::setTo(const uint8_t* bcd, int32_t length, int32_t scale, bool isNegative, UErrorCode& status) {
+    if (length > kDefaultDigits) {
+        fData.resize(length, 0);
+        fContext.digits = length;
+    } else {
+        fContext.digits = kDefaultDigits;
+    }
+
+    // "digits is of type int32_t, and must have a value in the range 1 through 999,999,999."
+    if (length < 1 || length > 999999999) {
+        // Too large for decNumber
+        status = U_UNSUPPORTED_ERROR;
+        return;
+    }
+    // "The exponent field holds the exponent of the number. Its range is limited by the requirement that
+    // "the range of the adjusted exponent of the number be balanced and fit within a whole number of
+    // "decimal digits (in this implementation, be –999,999,999 through +999,999,999). The adjusted
+    // "exponent is the exponent that would result if the number were expressed with a single digit before
+    // "the decimal point, and is therefore given by exponent+digits-1."
+    if (scale > 999999999 - length + 1 || scale < -999999999 - length + 1) {
+        // Too large for decNumber
+        status = U_UNSUPPORTED_ERROR;
+        return;
+    }
+
+    fData.getAlias()->digits = length;
+    fData.getAlias()->exponent = scale;
+    fData.getAlias()->bits = static_cast<uint8_t>(isNegative ? DECNEG : 0);
+    uprv_decNumberSetBCD(fData, bcd, static_cast<uint32_t>(length));
+    if (fContext.status != 0) {
+        // Some error occurred while constructing the decNumber.
+        status = U_INTERNAL_PROGRAM_ERROR;
+    }
+}
+
+void DecNum::normalize() {
+    uprv_decNumberReduce(fData, fData, &fContext);
+}
+
+void DecNum::multiplyBy(const DecNum& rhs, UErrorCode& status) {
+    uprv_decNumberMultiply(fData, fData, rhs.fData, &fContext);
+    if (fContext.status != 0) {
+        status = U_INTERNAL_PROGRAM_ERROR;
+    }
+}
+
+void DecNum::divideBy(const DecNum& rhs, UErrorCode& status) {
+    uprv_decNumberDivide(fData, fData, rhs.fData, &fContext);
+    if ((fContext.status & DEC_Inexact) != 0) {
+        // Ignore.
+    } else if (fContext.status != 0) {
+        status = U_INTERNAL_PROGRAM_ERROR;
+    }
+}
+
+bool DecNum::isNegative() const {
+    return decNumberIsNegative(fData.getAlias());
+}
+
+bool DecNum::isZero() const {
+    return decNumberIsZero(fData.getAlias());
+}
+
+void DecNum::toString(ByteSink& output, UErrorCode& status) const {
+    if (U_FAILURE(status)) {
+        return;
+    }
+    // "string must be at least dn->digits+14 characters long"
+    int32_t minCapacity = fData.getAlias()->digits + 14;
+    MaybeStackArray<char, 30> buffer(minCapacity);
+    uprv_decNumberToString(fData, buffer.getAlias());
+    output.Append(buffer.getAlias(), static_cast<int32_t>(uprv_strlen(buffer.getAlias())));
+}
+
+#endif /* #if !UCONFIG_NO_FORMATTING */