Archive/7z/Reader.cpp

/*
 * Copyright(c) Sophist Solutions, Inc. 1990-2026.  All rights reserved
 */
#include "Stroika/Foundation/StroikaPreComp.h"
 
#include "Stroika/Foundation/Characters/Format.h"
#include "Stroika/Foundation/Execution/Finally.h"
#include "Stroika/Foundation/Memory/BlockAllocated.h"
 
#include "Reader.h"
 
#if qStroika_HasComponent_LZMA
extern "C" {
#include <lzma/7z.h>
#include <lzma/7zCrc.h>
}
#endif
 
using namespace Stroika::Foundation;
using namespace Stroika::Foundation::Characters;
using namespace Stroika::Foundation::Containers;
using namespace Stroika::Foundation::DataExchange;
using namespace Stroika::Foundation::DataExchange::Archive;
using namespace Stroika::Foundation::Streams;
 
using Memory::StackBuffer;
using std::byte;
 
#if qStroika_HasComponent_LZMA
namespace {
    struct InitOnce_ {
        InitOnce_ ()
        {
            ::CrcGenerateTable ();
        }
    } sInitOnce_;
}
 
namespace {
 
    struct Rep_ : Reader::IRep {
    private:
        // could do smarter/block allocation or arena allocation, but KISS for now
        static void* Alloc_ (void* /*p*/, size_t size)
        {
            Require (size > 0);
            return new byte[size];
        }
        static void Free_ (void* /*p*/, void* address)
        {
            delete[] reinterpret_cast<byte*> (address);
        }
 
    private:
        mutable ISzAlloc fAllocImp_{};
        mutable ISzAlloc fAllocTempImp_{};
        CSzArEx          fDB_{};
        struct MyISeekInStream : ISeekInStream {
            Streams::InputStream::Ptr<byte> fInStream_;
            MyISeekInStream (const Streams::InputStream::Ptr<byte>& in)
                : fInStream_{in}
            {
                Read = Stream_Read_;
                Seek = Stream_Seek_;
            }
            static SRes Stream_Read_ (void* pp, void* buf, size_t* size)
            {
                MyISeekInStream* pThis = (MyISeekInStream*)pp;
                size_t           sz    = pThis->fInStream_.ReadBlocking (span{reinterpret_cast<byte*> (buf), *size}).size ();
                Assert (sz <= *size);
                *size = sz;
                return SZ_OK; // not sure on EOF/underflow?SZ_ERROR_READ
            }
            static SRes Stream_Seek_ (void* pp, Int64* pos, ESzSeek origin)
            {
                MyISeekInStream* pThis = (MyISeekInStream*)pp;
                switch (origin) {
                    case SZ_SEEK_SET:
                        *pos = pThis->fInStream_.Seek (*pos);
                        break;
                    case SZ_SEEK_CUR:
                        *pos = pThis->fInStream_.Seek (eFromCurrent, *pos);
                        break;
                    case SZ_SEEK_END:
                        *pos = pThis->fInStream_.Seek (eFromEnd, *pos);
                        break;
                    default:
                        AssertNotReached ();
                        return SZ_ERROR_UNSUPPORTED;
                }
                return SZ_OK;
            }
        };
        MyISeekInStream     fInSeekStream_;
        mutable CLookToRead fLookStream_{};
 
    public:
        Rep_ (const Streams::InputStream::Ptr<byte>& in)
            : fInSeekStream_{in}
        {
            fAllocImp_     = ISzAlloc{Alloc_, Free_};
            fAllocTempImp_ = ISzAlloc{Alloc_, Free_};
 
            ::SzArEx_Init (&fDB_);
 
            ::LookToRead_CreateVTable (&fLookStream_, false);
            fLookStream_.realStream = &fInSeekStream_;
 
            SRes ret{};
            if ((ret = ::SzArEx_Open (&fDB_, &fLookStream_.s, &fAllocImp_, &fAllocTempImp_)) != SZ_OK) {
                // throw
                throw "bad";
            }
        }
        ~Rep_ ()
        {
            ::SzArEx_Free (&fDB_, &fAllocImp_);
        }
        virtual Set<String> GetContainedFiles () const override
        {
            Set<String> result;
            for (unsigned int i = 0; i < fDB_.NumFiles; ++i) {
                if (not SzArEx_IsDir (&fDB_, i)) {
                    size_t nameLen = ::SzArEx_GetFileNameUtf16 (&fDB_, i, nullptr);
                    if (nameLen < 1) {
                        break;
                    }
                    StackBuffer<char16_t>   fileName{Memory::eUninitialized, nameLen};
                    [[maybe_unused]] size_t z = ::SzArEx_GetFileNameUtf16 (&fDB_, i, reinterpret_cast<UInt16*> (&fileName[0]));
                    result.Add (String{&fileName[0]});
                }
            }
            return result;
        }
        virtual Memory::BLOB GetData (const String& fileName) const override
        {
            UInt32 idx = GetIdx_ (fileName);
            if (idx == -1) {
                throw "bad"; //filenotfound
            }
 
            byte*  outBuffer     = 0;          // it must be 0 before first call for each new archive
            UInt32 blockIndex    = 0xFFFFFFFF; // can have any value if outBuffer = 0
            size_t outBufferSize = 0;          // can have any value if outBuffer = 0
 
            size_t offset{};
            size_t outSizeProcessed{};
 
            [[maybe_unused]] auto&& cleanup = Execution::Finally ([&outBuffer, this] () noexcept { IAlloc_Free (&fAllocImp_, outBuffer); });
 
            SRes ret;
            if ((ret = ::SzArEx_Extract (&fDB_, &fLookStream_.s, idx, &blockIndex, reinterpret_cast<uint8_t**> (&outBuffer), &outBufferSize,
                                         &offset, &outSizeProcessed, &fAllocImp_, &fAllocTempImp_)) != SZ_OK) {
                throw "bad";
            }
            return Memory::BLOB (outBuffer + offset, outBuffer + offset + outSizeProcessed);
        }
        UInt32 GetIdx_ (const String& fn) const
        {
            // could create map to lookup once and maintain
            for (UInt32 i = 0; i < fDB_.NumFiles; ++i) {
                if (not SzArEx_IsDir (&fDB_, i)) {
                    size_t nameLen = SzArEx_GetFileNameUtf16 (&fDB_, i, nullptr);
                    if (nameLen < 1) {
                        break;
                    }
                    StackBuffer<char16_t>   fileName{Memory::eUninitialized, nameLen};
                    [[maybe_unused]] size_t z = ::SzArEx_GetFileNameUtf16 (&fDB_, i, reinterpret_cast<UInt16*> (&fileName[0]));
                    if (String{&fileName[0]} == fn) {
                        return i;
                    }
                }
            }
            return static_cast<UInt32> (-1);
        }
    };
}
 
/*
 ********************************************************************************
 ***************** DataExchange::Archive::_7z::Reader::New **********************
 ********************************************************************************
 */
Archive::Reader::Ptr Archive::_7z::Reader::New (const Streams::InputStream::Ptr<byte>& readFrom)
{
    return Archive::Reader::Ptr{Memory::MakeSharedPtr<Rep_> (readFrom)};
}
 
#endif