JavaScriptCore-903.tar.gz

[apple/javascriptcore.git] / wtf / DecimalNumber.h

diff --git a/wtf/DecimalNumber.h b/wtf/DecimalNumber.h
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+++ b/wtf/DecimalNumber.h
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+/*
+ * Copyright (C) 2010 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef DecimalNumber_h
+#define DecimalNumber_h
+
+#include <math.h>
+#include <wtf/dtoa.h>
+#include <wtf/MathExtras.h>
+#include <wtf/text/WTFString.h>
+
+namespace WTF {
+
+enum RoundingSignificantFiguresType { RoundingSignificantFigures };
+enum RoundingDecimalPlacesType { RoundingDecimalPlaces };
+
+class DecimalNumber {
+public:
+    DecimalNumber(double d)
+    {
+        ASSERT(!isnan(d) && !isinf(d));
+        dtoa(m_significand, d, m_sign, m_exponent, m_precision);
+
+        ASSERT(m_precision);
+        // Zero should always have exponent 0.
+        ASSERT(m_significand[0] != '0' || !m_exponent);
+        // No values other than zero should have a leading zero.
+        ASSERT(m_significand[0] != '0' || m_precision == 1);
+        // No values other than zero should have trailing zeros.
+        ASSERT(m_significand[0] == '0' || m_significand[m_precision - 1] != '0');
+    }
+
+    DecimalNumber(double d, RoundingSignificantFiguresType, unsigned significantFigures)
+    {
+        ASSERT(!isnan(d) && !isinf(d));
+        dtoaRoundSF(m_significand, d, significantFigures, m_sign, m_exponent, m_precision);
+
+        ASSERT(significantFigures && significantFigures <= sizeof(DtoaBuffer));
+        while (m_precision < significantFigures)
+            m_significand[m_precision++] = '0';
+
+        ASSERT(m_precision);
+        // Zero should always have exponent 0.
+        ASSERT(m_significand[0] != '0' || !m_exponent);
+    }
+
+    DecimalNumber(double d, RoundingDecimalPlacesType, unsigned decimalPlaces)
+    {
+        ASSERT(!isnan(d) && !isinf(d));
+        dtoaRoundDP(m_significand, d, decimalPlaces, m_sign, m_exponent, m_precision);
+
+        unsigned significantFigures = 1 + m_exponent + decimalPlaces;
+        ASSERT(significantFigures && significantFigures <= sizeof(DtoaBuffer));
+        while (m_precision < significantFigures)
+            m_significand[m_precision++] = '0';
+
+        ASSERT(m_precision);
+        // Zero should always have exponent 0.
+        ASSERT(m_significand[0] != '0' || !m_exponent);
+    }
+
+    unsigned bufferLengthForStringDecimal() const;
+    unsigned bufferLengthForStringExponential() const;
+
+    unsigned toStringDecimal(UChar* buffer, unsigned bufferLength) const;
+    unsigned toStringExponential(UChar* buffer, unsigned bufferLength) const;
+
+    bool sign() const { return m_sign; }
+    int exponent() const { return m_exponent; }
+    const char* significand() const { return m_significand; } // significand contains precision characters, is not null-terminated.
+    unsigned precision() const { return m_precision; }
+
+private:
+    bool m_sign;
+    int m_exponent;
+    DtoaBuffer m_significand;
+    unsigned m_precision;
+};
+
+} // namespace WTF
+
+using WTF::DecimalNumber;
+using WTF::RoundingSignificantFigures;
+using WTF::RoundingDecimalPlaces;
+
+#endif // DecimalNumber_h