Move WTF string to number converter functions to StringToNumber.h

third_party/WebKit/Source/wtf/text/StringToNumber.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "wtf/text/StringToNumber.h"
+
+#include "wtf/ASCIICType.h"
+#include "wtf/dtoa.h"
+#include "wtf/text/StringImpl.h"
+
+namespace WTF {
+
+static bool isCharacterAllowedInBase(UChar c, int base)
+{
+    if (c > 0x7F)
+        return false;
+    if (isASCIIDigit(c))
+        return c - '0' < base;
+    if (isASCIIAlpha(c)) {
+        if (base > 36)
+            base = 36;
+        return (c >= 'a' && c < 'a' + base - 10)
+            || (c >= 'A' && c < 'A' + base - 10);
+    }
+    return false;
+}
+
+template <typename IntegralType, typename CharType>
+static inline IntegralType toIntegralType(const CharType* data, size_t length, bool* ok, int base)
+{
+    static const IntegralType integralMax = std::numeric_limits<IntegralType>::max();
+    static const bool isSigned = std::numeric_limits<IntegralType>::is_signed;
+    const IntegralType maxMultiplier = integralMax / base;
+
+    IntegralType value = 0;
+    bool isOk = false;
+    bool isNegative = false;
+
+    if (!data)
+        goto bye;
+
+    // skip leading whitespace
+    while (length && isSpaceOrNewline(*data)) {
+        --length;
+        ++data;
+    }
+
+    if (isSigned && length && *data == '-') {
+        --length;
+        ++data;
+        isNegative = true;
+    } else if (length && *data == '+') {
+        --length;
+        ++data;
+    }
+
+    if (!length || !isCharacterAllowedInBase(*data, base))
+        goto bye;
+
+    while (length && isCharacterAllowedInBase(*data, base)) {
+        --length;
+        IntegralType digitValue;
+        CharType c = *data;
+        if (isASCIIDigit(c))
+            digitValue = c - '0';
+        else if (c >= 'a')
+            digitValue = c - 'a' + 10;
+        else
+            digitValue = c - 'A' + 10;
+
+        if (value > maxMultiplier || (value == maxMultiplier && digitValue > (integralMax % base) + isNegative))
+            goto bye;
+
+        value = base * value + digitValue;
+        ++data;
+    }
+
+#if COMPILER(MSVC)
+#pragma warning(push, 0)
+#pragma warning(disable:4146)
+#endif
+
+    if (isNegative)
+        value = -value;
+
+#if COMPILER(MSVC)
+#pragma warning(pop)
+#endif
+
+    // skip trailing space
+    while (length && isSpaceOrNewline(*data)) {
+        --length;
+        ++data;
+    }
+
+    if (!length)
+        isOk = true;
+bye:
+    if (ok)
+        *ok = isOk;
+    return isOk ? value : 0;
+}
+
+template <typename CharType>
+static unsigned lengthOfCharactersAsInteger(const CharType* data, size_t length)
+{
+    size_t i = 0;
+
+    // Allow leading spaces.
+    for (; i != length; ++i) {
+        if (!isSpaceOrNewline(data[i]))
+            break;
+    }
+
+    // Allow sign.
+    if (i != length && (data[i] == '+' || data[i] == '-'))
+        ++i;
+
+    // Allow digits.
+    for (; i != length; ++i) {
+        if (!isASCIIDigit(data[i]))
+            break;
+    }
+
+    return i;
+}
+
+int charactersToIntStrict(const LChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<int, LChar>(data, length, ok, base);
+}
+
+int charactersToIntStrict(const UChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<int, UChar>(data, length, ok, base);
+}
+
+unsigned charactersToUIntStrict(const LChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<unsigned, LChar>(data, length, ok, base);
+}
+
+unsigned charactersToUIntStrict(const UChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<unsigned, UChar>(data, length, ok, base);
+}
+
+int64_t charactersToInt64Strict(const LChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<int64_t, LChar>(data, length, ok, base);
+}
+
+int64_t charactersToInt64Strict(const UChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<int64_t, UChar>(data, length, ok, base);
+}
+
+uint64_t charactersToUInt64Strict(const LChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<uint64_t, LChar>(data, length, ok, base);
+}
+
+uint64_t charactersToUInt64Strict(const UChar* data, size_t length, bool* ok, int base)
+{
+    return toIntegralType<uint64_t, UChar>(data, length, ok, base);
+}
+
+int charactersToInt(const LChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<int, LChar>(data, lengthOfCharactersAsInteger<LChar>(data, length), ok, 10);
+}
+
+int charactersToInt(const UChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<int, UChar>(data, lengthOfCharactersAsInteger(data, length), ok, 10);
+}
+
+unsigned charactersToUInt(const LChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<unsigned, LChar>(data, lengthOfCharactersAsInteger<LChar>(data, length), ok, 10);
+}
+
+unsigned charactersToUInt(const UChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<unsigned, UChar>(data, lengthOfCharactersAsInteger<UChar>(data, length), ok, 10);
+}
+
+int64_t charactersToInt64(const LChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<int64_t, LChar>(data, lengthOfCharactersAsInteger<LChar>(data, length), ok, 10);
+}
+
+int64_t charactersToInt64(const UChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<int64_t, UChar>(data, lengthOfCharactersAsInteger<UChar>(data, length), ok, 10);
+}
+
+uint64_t charactersToUInt64(const LChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<uint64_t, LChar>(data, lengthOfCharactersAsInteger<LChar>(data, length), ok, 10);
+}
+
+uint64_t charactersToUInt64(const UChar* data, size_t length, bool* ok)
+{
+    return toIntegralType<uint64_t, UChar>(data, lengthOfCharactersAsInteger<UChar>(data, length), ok, 10);
+}
+
+enum TrailingJunkPolicy { DisallowTrailingJunk, AllowTrailingJunk };
+
+template <typename CharType, TrailingJunkPolicy policy>
+static inline double toDoubleType(const CharType* data, size_t length, bool* ok, size_t& parsedLength)
+{
+    size_t leadingSpacesLength = 0;
+    while (leadingSpacesLength < length && isASCIISpace(data[leadingSpacesLength]))
+        ++leadingSpacesLength;
+
+    double number = parseDouble(data + leadingSpacesLength, length - leadingSpacesLength, parsedLength);
+    if (!parsedLength) {
+        if (ok)
+            *ok = false;
+        return 0.0;
+    }
+
+    parsedLength += leadingSpacesLength;
+    if (ok)
+        *ok = policy == AllowTrailingJunk || parsedLength == length;
+    return number;
+}
+
+double charactersToDouble(const LChar* data, size_t length, bool* ok)
+{
+    size_t parsedLength;
+    return toDoubleType<LChar, DisallowTrailingJunk>(data, length, ok, parsedLength);
+}
+
+double charactersToDouble(const UChar* data, size_t length, bool* ok)
+{
+    size_t parsedLength;
+    return toDoubleType<UChar, DisallowTrailingJunk>(data, length, ok, parsedLength);
+}
+
+double charactersToDouble(const LChar* data, size_t length, size_t& parsedLength)
+{
+    return toDoubleType<LChar, AllowTrailingJunk>(data, length, nullptr, parsedLength);
+}
+
+double charactersToDouble(const UChar* data, size_t length, size_t& parsedLength)
+{
+    return toDoubleType<UChar, AllowTrailingJunk>(data, length, nullptr, parsedLength);
+}
+
+float charactersToFloat(const LChar* data, size_t length, bool* ok)
+{
+    // FIXME: This will return ok even when the string fits into a double but
+    // not a float.
+    size_t parsedLength;
+    return static_cast<float>(toDoubleType<LChar, DisallowTrailingJunk>(data, length, ok, parsedLength));
+}
+
+float charactersToFloat(const UChar* data, size_t length, bool* ok)
+{
+    // FIXME: This will return ok even when the string fits into a double but
+    // not a float.
+    size_t parsedLength;
+    return static_cast<float>(toDoubleType<UChar, DisallowTrailingJunk>(data, length, ok, parsedLength));
+}
+
+float charactersToFloat(const LChar* data, size_t length, size_t& parsedLength)
+{
+    // FIXME: This will return ok even when the string fits into a double but
+    // not a float.
+    return static_cast<float>(toDoubleType<LChar, AllowTrailingJunk>(data, length, 0, parsedLength));
+}
+
+float charactersToFloat(const UChar* data, size_t length, size_t& parsedLength)
+{
+    // FIXME: This will return ok even when the string fits into a double but
+    // not a float.
+    return static_cast<float>(toDoubleType<UChar, AllowTrailingJunk>(data, length, 0, parsedLength));
+}
+
+} // namespace WTF