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#include "qv4function_p.h"
#include "qv4managed_p.h"
#include "qv4string_p.h"
#include "qv4value_p.h"
#include "qv4engine_p.h"
#include "qv4lookup_p.h"

QT_BEGIN_NAMESPACE

using namespace QV4;

Function::Function(ExecutionEngine *engine, CompiledData::CompilationUnit *unit, const CompiledData::Function *function,
                   ReturnedValue (*codePtr)(ExecutionContext *, const uchar *), quint32 _codeSize)
        : compiledFunction(function)
        , compilationUnit(unit)
        , code(codePtr)
        , codeData(0)
        , codeSize(_codeSize)
{
    Q_UNUSED(engine);

    name = compilationUnit->runtimeStrings[compiledFunction->nameIndex].asString();

    nArguments = compiledFunction->nFormals;

    internalClass = engine->emptyClass;
    const quint32 *formalsIndices = compiledFunction->formalsTable();
    // iterate backwards, so we get the right ordering for duplicate names
    for (int i = static_cast<int>(compiledFunction->nFormals - 1); i >= 0; --i) {
        String *arg = compilationUnit->runtimeStrings[formalsIndices[i]].asString();
        while (1) {
            InternalClass *newClass = internalClass->addMember(arg, Attr_NotConfigurable);
            if (newClass != internalClass) {
                internalClass = newClass;
                break;
            }
            // duplicate arguments, need some trick to store them
            arg = new (engine->memoryManager) String(engine, arg, engine->newString(QString(0xfffe))->getPointer());
        }
    }

    const quint32 *localsIndices = compiledFunction->localsTable();
    for (quint32 i = 0; i < compiledFunction->nLocals; ++i) {
        String *local = compilationUnit->runtimeStrings[localsIndices[i]].asString();
        internalClass = internalClass->addMember(local, Attr_NotConfigurable);
    }
}

Function::~Function()
{
}


void Function::mark(ExecutionEngine *e)
{
    name.mark(e);
}

namespace QV4 {
template <int field, typename SearchType>
struct LineNumberMappingHelper
{
    const quint32 *table;
    int lowerBound(int begin, int end, SearchType value) {
        int middle;
        int n = int(end - begin);
        int half;

        while (n > 0) {
            half = n >> 1;
            middle = begin + half;
            if (table[middle * 2 + field] < static_cast<quint32>(value)) {
                begin = middle + 1;
                n -= half + 1;
            } else {
                n = half;
            }
        }
        return begin;
    }
    int upperBound(int begin, int end, SearchType value) {
        int middle;
        int n = int(end - begin);
        int half;

        while (n > 0) {
            half = n >> 1;
            middle = begin + half;
            if (value < table[middle * 2 + field]) {
                n = half;
            } else {
                begin = middle + 1;
                n -= half + 1;
            }
        }
        return begin;
    }
};
}

int Function::lineNumberForProgramCounter(qptrdiff offset) const
{
    // Access the first field, the program counter
    LineNumberMappingHelper<0, qptrdiff> helper;
    helper.table = compiledFunction->lineNumberMapping();
    const uint count = compiledFunction->nLineNumberMappingEntries;

    int pos = helper.lowerBound(0, count, offset);
    if (pos != 0 && count > 0)
        --pos;
    if (static_cast<uint>(pos) == count)
        return -1;
    return helper.table[pos * 2 + 1];
}

QList<qptrdiff> Function::programCountersForAllLines() const
{
    // Only store 1 breakpoint per line...
    QHash<quint32, qptrdiff> offsetsPerLine;
    const quint32 *mapping = compiledFunction->lineNumberMapping();

    // ... and make it the first instruction by walking backwards over the line mapping table
    // and inserting all entries keyed on line.
    for (quint32 i = compiledFunction->nLineNumberMappingEntries; i > 0; ) {
        --i; // the loop is written this way, because starting at endIndex-1 and checking for i>=0 will never end: i>=0 is always true for unsigned.
        quint32 offset = mapping[i * 2];
        quint32 line = mapping[i * 2 + 1];
        offsetsPerLine.insert(line, offset);
    }

    return offsetsPerLine.values();
}

QT_END_NAMESPACE