/*
 *  This file is part of RawTherapee.
 *
 *  RawTherapee is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  RawTherapee is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with RawTherapee.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <iostream>
#include <vector>
#include "dcraw.h"

#include "rt_math.h"

// Code adapted from libraw
/* -*- C++ -*-
 * Copyright (C) 2022-2024 Alex Tutubalin, LibRaw LLC
 *
 LibRaw is free software; you can redistribute it and/or modify
 it under the terms of the one of two licenses as you choose:

1. GNU LESSER GENERAL PUBLIC LICENSE version 2.1
   (See file LICENSE.LGPL provided in LibRaw distribution archive for details).

2. COMMON DEVELOPMENT AND DISTRIBUTION LICENSE (CDDL) Version 1.0
   (See file LICENSE.CDDL provided in LibRaw distribution archive for details).

*/

namespace
{

using pana8_tags_t = DCraw::PanasonicRW2Info::v8_tags_t;
using ushort = DCraw::ushort;
using INT64 = DCraw::INT64;

// in 8-byte words, 800kb
#define PANA8_BUFSIZE 102400

class pana8_bufio_t
{
public:
    pana8_bufio_t(rtengine::IMFILE *stream, INT64 start, uint32_t len) :
        data(PANA8_BUFSIZE), input(stream), baseoffset(start), begin(0), end(0), _size(len)
    {
    }
    uint32_t size() { return ((_size + 7) / 8) * 8; }
    uint64_t getQWord(uint32_t offset)
    {
        if (offset >= begin && offset < end)
            return data[offset - begin];
        if (!input) return 0;
        refill(offset);
        if (offset >= begin && offset < end)
            return data[offset - begin];
        return 0;
    }
    void refill(uint32_t newoffset);

    std::vector<uint64_t> data;
    rtengine::IMFILE *input;
    INT64 baseoffset;
    INT64 begin, end;
    uint32_t _size;
};

struct pana8_param_t {
    uint32_t range_shift, gamma_base;
    uint32_t tag3A[6];
    uint32_t tag39[6];
    uint32_t tag3B;
    uint32_t initial[4];
    uint32_t huff_coeff[17];
    uint32_t tag3B_2;
    uint32_t noGammaFlag;
    uint64_t hufftable1[17];
    uint64_t hufftable2[17];
    std::vector<uint16_t> gammaTable;
    std::vector<uint8_t> extrahuff;

    pana8_param_t(const pana8_tags_t &init);
    int32_t gammaCurve(uint32_t i);
    bool DecodeC8(
        pana8_bufio_t &bufio,
        unsigned int width, unsigned int height, ushort *raw_image, ushort raw_width, ushort raw_height, uint16_t left_margin);
    uint32_t GetDBit(uint64_t a2);
};

void invertBits(void *buf, size_t size);

void pana8_bufio_t::refill(uint32_t newoffset)
{
    if (newoffset >= begin && newoffset < end)
        return;
    uint32_t readwords, remainwords, toread;
#ifdef _OPENMP
#pragma omp critical
    {
#endif
        fseek(input, baseoffset + newoffset * sizeof(int64_t), SEEK_SET);
        remainwords = (_size - newoffset * sizeof(int64_t) + 7) >> 3;
        toread = MIN(PANA8_BUFSIZE, remainwords);
        uint32_t readbytes = fread(data.data(), 1, toread * sizeof(uint64_t), input);
        readwords = (readbytes + 7) >> 3;
#ifdef _OPENMP
    }
#endif

    if (INT64(readwords) < INT64(toread) - 1LL)
        throw std::runtime_error("Unexpected end of file in CRX bitstream");

    if (readwords > 0)
        invertBits(data.data(), readwords * sizeof(uint64_t));
    begin = newoffset;
    end = newoffset + readwords;
}

struct pana8_base_t {
    pana8_base_t() { coeff[0] = coeff[1] = coeff[2] = coeff[3] = 0; }
    pana8_base_t(const pana8_base_t &s) { clone(s.coeff); }
    void clone(const uint32_t *scoeff)
    { // TODO: implement SSE load for SSE-enabled code
        coeff[0] = scoeff[0];
        coeff[1] = scoeff[1];
        coeff[2] = scoeff[2];
        coeff[3] = scoeff[3];
    }
    uint32_t coeff[4];
};

bool pana8_param_t::DecodeC8(pana8_bufio_t &bufio, unsigned int width, unsigned int height, ushort *raw_image, ushort raw_width, ushort raw_height, uint16_t left_margin)
{
    unsigned halfwidth = width >> 1;
    unsigned halfheight = height >> 1;
    if (!halfwidth || !halfheight || bufio.size() < 9)
        return false; // invalid input

    uint32_t datamax = tag3B_2 >> range_shift;

    pana8_base_t start_coeff;
    for (int i = 0; i < 4; i++)
        start_coeff.coeff[i] = initial[i] & 0xffffu;

    bool _extrahuff = (extrahuff.size() >= 0x10000);

    uint8_t *big_huff_table = nullptr;
    if (_extrahuff)
        big_huff_table = extrahuff.data();

    uint16_t *gammatable = (gammaTable.size() >= 0x10000) && !noGammaFlag ? (uint16_t *)gammaTable.data() : 0;

#ifdef PANA8_FULLY_BUFFERED
    const uint8_t *inputbyteptr = source.data();
    uint32_t jobsz_in_qwords = source.size() >> 3;
#else
    uint32_t jobsz_in_qwords = bufio.size() >> 3;
#endif
    int32_t doublewidth = 4 * halfwidth;
    std::vector<uint8_t> outline(4 * doublewidth);
    pana8_base_t line_base(start_coeff);
    int64_t bittail = 0LL;
    int32_t bitportion = 0;
    uint32_t inqword = 0u;

    try {
        for (uint32_t current_row = 0; current_row < halfheight; current_row++) {
            uint8_t *outrowp = outline.data();
            pana8_base_t current_base(line_base);

            for (int32_t col = 0; col < doublewidth; col++) {
                uint64_t pixbits;
                if (bitportion < 0) {
                    uint32_t inqword_next = inqword + 1;
                    if ((int)inqword + 1 >= int(jobsz_in_qwords))
                        return false;
                    bitportion += 64;
                    uint64_t inputqword = bufio.getQWord(inqword);
                    uint64_t inputqword_next = bufio.getQWord(inqword_next);
                    pixbits = (inputqword_next >> bitportion) | (inputqword << (64 - (uint8_t)(bitportion & 0xffu)));
                    if ((unsigned int)inqword < jobsz_in_qwords)
                        inqword = inqword_next;
                } else {
                    if ((unsigned int)inqword >= jobsz_in_qwords)
                        return false;
                    uint64_t inputqword = bufio.getQWord(inqword);
                    pixbits = (inputqword >> bitportion) | bittail;
                    uint32_t step = (bitportion == 0);
                    if (!bitportion)
                        bitportion = 64;
                    inqword += step;
                }
                int huff_index = 0;
                if (_extrahuff) {
                    huff_index = *(uint8_t *)(big_huff_table + ((pixbits >> 48) & 0xffffu));
                } else {
                    huff_index = int(GetDBit(pixbits));
                    datamax = tag3B_2;
                }
                int32_t v37 = (huff_coeff[huff_index] >> 24) & 0x1F;
                uint32_t hc = huff_coeff[huff_index];
                int64_t v38 = pixbits << (((hc >> 16) & 0xffffu) & 0x1F);
                uint64_t v90 = (uint32_t)(huff_index - v37);
                int32_t v39 = (uint16_t)((uint64_t)v38 >> ((uint8_t)v37 - (uint8_t)huff_index)) << ((huff_coeff[huff_index] >> 24) & 0xffu);

                if (huff_index - v37 <= 0)
                    v39 &= 0xffff0000u;

                int32_t delta1;
                if (v38 < 0) {
                    delta1 = (uint16_t)v39;
                } else if (huff_index) {
                    int32_t v40 = -1 << huff_index;
                    if ((uint8_t)v37)
                        delta1 = (uint16_t)v39 + v40;
                    else
                        delta1 = (uint16_t)v39 + v40 + 1;
                } else {
                    delta1 = 0;
                }

                uint32_t v42 = bitportion - ((huff_coeff[huff_index] >> 16) & 0x1F);
                int32_t delta2 = uint8_t(v37) ? 1 << (v37 - 1) : 0;
                uint32_t *destpixel = (uint32_t *)(outrowp + 16LL * (col >> 2));

                int32_t delta = delta1 + delta2;
                int32_t col_amp_3 = col & 3;
                if (col_amp_3 == 2) {
                    int32_t val = current_base.coeff[1] + delta;
                    destpixel[1] = uint32_t(rtengine::LIM(val, 0, int(datamax)));
                } else if (col_amp_3 == 1) {
                    int32_t val = current_base.coeff[2] + delta;
                    destpixel[2] = uint32_t(rtengine::LIM(val, 0, int(datamax)));
                } else if ((col & 3) != 0) { // == 3
                    int32_t val = current_base.coeff[3] + delta;
                    destpixel[3] = uint32_t(rtengine::LIM(val, 0, int(datamax)));
                } else { // 0
                    int32_t val = current_base.coeff[0] + delta;
                    destpixel[0] = uint32_t(rtengine::LIM(val, 0, int(datamax)));
                }
                if (huff_index <= v37)
                    v90 = 0LL;
                bittail = v38 << v90;
                bitportion = int32_t(v42 - v90);

                if (col_amp_3 == 3)
                    current_base.clone((uint32_t *)(outrowp + 16LL * (col >> 2)));
                if (col == 3)
                    line_base.clone((uint32_t *)(outrowp));
            }

            int destrow = current_row * 2;
            uint16_t *destrow0 = raw_image + (destrow * raw_width) + left_margin;
            uint16_t *destrow1 =
                raw_image + (destrow + 1) * raw_width + left_margin;
            uint16_t *srcrow = (uint16_t *)(outrowp);
            if (gammatable) {
                for (unsigned col = 0; col < width - 1; col += 2) {
                    const int c6 = col * 4;
                    destrow0[col] = gammatable[srcrow[c6]];
                    destrow0[col + 1] = gammatable[srcrow[c6 + 2]];
                    destrow1[col] = gammatable[srcrow[c6 + 4]];
                    destrow1[col + 1] = gammatable[srcrow[c6 + 6]];
                }
            } else {
                for (unsigned col = 0; col < width - 1; col += 2) {
                    const int c6 = col * 4;
                    destrow0[col] = srcrow[c6];
                    destrow0[col + 1] = srcrow[c6 + 2];
                    destrow1[col] = srcrow[c6 + 4];
                    destrow1[col + 1] = srcrow[c6 + 6];
                }
            }
        }
    } catch (...) { // buffer read may throw an exception
        return false;
    }

    return true;
}

uint32_t pana8_param_t::GetDBit(uint64_t a2)
{
    for (int i = 0; i < 16; i++) {
        if ((a2 & hufftable2[i]) == hufftable1[i])
            return i;
    }

    return uint32_t((hufftable2[16] & a2) == hufftable1[16]) ^ 0x11u;
}

pana8_param_t::pana8_param_t(const pana8_tags_t &meta) :
    gammaTable(0)
{
    range_shift = gamma_base = tag3B = 0;

    memset(tag3A, 0, sizeof(tag3A));
    memset(tag39, 0, sizeof(tag3A));
    memset(tag3A, 0, sizeof(tag3A));
    memset(initial, 0, sizeof(tag3A));
    memset(huff_coeff, 0, sizeof(tag3A));
    memset(hufftable1, 0, sizeof(tag3A));
    memset(hufftable2, 0, sizeof(tag3A));

    noGammaFlag = 1;

    for (int i = 0; i < 6; i++) {
        tag3A[i] = meta.tag3A[i];
        tag39[i] = meta.tag39[i];
    }

    tag3B_2 = tag3B = meta.tag3B;

    for (int i = 0; i < 4; i++)
        initial[i] = meta.initial[i];

    for (int i = 0; i < 17; i++)
        huff_coeff[i] = (uint32_t(meta.tag41[i]) << 24) | (uint32_t(meta.tag40a[i]) << 16) | meta.tag40b[i];

    std::vector<uint16_t> tempGamma(0x10000);
    for (unsigned i = 0; i < 0x10000; i++) {
        uint64_t val = gammaCurve(i);
        tempGamma[i] = uint16_t(val & 0xffffu);
        if (i != val)
            noGammaFlag = 0;
    }

    if (!noGammaFlag)
        gammaTable = tempGamma;

    int v7 = 0;

    for (unsigned hindex = 0; hindex < 17; hindex++) {
        uint32_t hc = huff_coeff[hindex];
        uint32_t hlow = (hc >> 16) & 0x1F;
        int16_t v8 = 0;
        if ((hc & 0x1F0000) != 0) {
            int h7 = ((hc >> 16) & 0xffffu) & 7;
            if (hlow - 1 >= 7) {
                uint32_t hdiff = h7 - hlow;
                v8 = 0;
                do {
                    v8 = (v8 << 8) | 0xFFu;
                    hdiff += 8;
                } while (hdiff);
            } else {
                v8 = 0;
            }
            for (; h7; --h7) {
                v8 = 2 * v8 + 1;
            }
        }

        uint16_t v9 = hc & v8;
        if (uint32_t(v7) < hlow) {
            v7 = ((huff_coeff[hindex] >> 16) & 0xFFFFu) & 0x1F;
        }
        hufftable2[hindex] = 0xFFFFULL << (64 - hlow);
        hufftable1[hindex] = (uint64_t)v9 << (64 - hlow);
    }

    if (v7 < 17) {
        if (extrahuff.size() < 0x10000)
            extrahuff.resize(0x10000);
        uint64_t v17 = 0LL;

        for (int j = 0LL; j < 0x10000; ++j) {
            extrahuff[j] = uint8_t(GetDBit(v17) & 0xffu);
            v17 += 0x1000000000000ULL;
        }
    }
}

int32_t pana8_param_t::gammaCurve(uint32_t idx)
{
    unsigned int v2 = idx | 0xFFFF0000;
    if ((idx & 0x10000) == 0)
        v2 = idx & 0x1FFFF;

    int v3 = gamma_base + v2;
    unsigned int v4 = MIN(v3, 0xFFFF);

    int v5 = 0;
    if ((v4 & 0x80000000) != 0)
        v4 = 0;

    if (v4 >= (0xFFFF & tag3A[1])) {
        v5 = 1;
        if (v4 >= (0xFFFF & tag3A[2])) {
            v5 = 2;
            if (v4 >= (0xFFFF & tag3A[3])) {
                v5 = 3;
                if (v4 >= (0xFFFF & tag3A[4]))
                    v5 = ((v4 | 0x500000000LL) - (uint64_t)(0xFFFF & tag3A[5])) >> 32;
            }
        }
    }
    unsigned int v6 = tag3A[v5];
    int v7 = tag39[v5];
    unsigned int v8 = v4 - (uint16_t)v6;
    char v9 = v7 & 0x1F;
    int64_t result = 0;

    if (v9 == 31) {
        result = v5 == 5 ? 0xFFFFLL : ((tag3A[v5 + 1] >> 16) & 0xFFFF);
        return MIN(uint32_t(result), tag3B);
    }
    if ((v7 & 0x10) == 0) {
        if (v9 == 15) {
            result = ((v6 >> 16) & 0xFFFF);
            return MIN(uint32_t(result), tag3B);
        } else if (v9 != 0) {
            v8 = (v8 + (1 << (v9 - 1))) >> v9;
        }
    } else {
        v8 <<= v7 & 0xF;
    }

    result = v8 + ((v6 >> 16) & 0xFFFF);

    return MIN(uint32_t(result), tag3B);
}

const static uint8_t _bitRevTable[256] = {
    0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0, 0x08, 0x88, 0x48,
    0xC8, 0x28, 0xA8, 0x68, 0xE8, 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4,
    0x64, 0xE4, 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4, 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, 0x1C,
    0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, 0x12, 0x92, 0x52, 0xD2,
    0x32, 0xB2, 0x72, 0xF2, 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A,
    0xFA, 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6, 0x0E, 0x8E,
    0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, 0x01, 0x81, 0x41, 0xC1, 0x21,
    0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1, 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
    0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9, 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, 0x15, 0x95, 0x55,
    0xD5, 0x35, 0xB5, 0x75, 0xF5, 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD,
    0x7D, 0xFD, 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, 0x0B,
    0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, 0x07, 0x87, 0x47, 0xC7,
    0x27, 0xA7, 0x67, 0xE7, 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F,
    0xEF, 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF};

void invertBits(void *buf, size_t size)
{
    unsigned sz = unsigned(size / 8);
    uint64_t *ptr = static_cast<uint64_t *>(buf);
    for (unsigned i = 0; i < sz; i++) {
        uint8_t *b = reinterpret_cast<uint8_t *>(&ptr[i]);
        uint64_t r = ((uint64_t)_bitRevTable[b[0]] << 56) | ((uint64_t)_bitRevTable[b[1]] << 48) |
                     ((uint64_t)_bitRevTable[b[2]] << 40) | ((uint64_t)_bitRevTable[b[3]] << 32) |
                     ((uint64_t)_bitRevTable[b[4]] << 24) | ((uint64_t)_bitRevTable[b[5]] << 16) |
                     ((uint64_t)_bitRevTable[b[6]] << 8) | _bitRevTable[b[7]];
        ptr[i] = r;
    }
}

} // namespace

unsigned DCraw::pana_bits_t::operator() (int nbits, unsigned *bytes)
{
    int byte;

    if (!nbits && !bytes) {
        return vbits=0;
    }
    if (!vbits) {
        fread (buf+load_flags, 1, 0x4000-load_flags, ifp);
        fread (buf, 1, load_flags, ifp);
    }
    if (encoding == 5) {
        for (byte = 0; byte < 16; byte++)
        {
          bytes[byte] = buf[vbits++];
          vbits &= 0x3FFF;
        }
        return 0;
    } else {
        vbits = (vbits - nbits) & 0x1ffff;
        byte = vbits >> 3 ^ 0x3ff0;
        return (buf[byte] | buf[byte+1] << 8) >> (vbits & 7) & ~(-1 << nbits);
    }
}

namespace
{

class pana_cs6_page_decoder
{
    unsigned int pixelbuffer[18], lastoffset, maxoffset;
    unsigned char current, *buffer;
public:
    pana_cs6_page_decoder(unsigned char *_buffer, unsigned int bsize)
      : pixelbuffer{}, lastoffset(0), maxoffset(bsize), current(0), buffer(_buffer)
    {
    }
    void read_page(); // will throw IO error if not enough space in buffer
    void read_page12(); // 12-bit variant
    unsigned int nextpixel()
    {
        return current < 14 ? pixelbuffer[current++] : 0;
    }
    unsigned int nextpixel12()
    {
        return current < 18 ? pixelbuffer[current++] : 0;
    }
};

#define wbuffer(i) ((unsigned short)buffer[lastoffset + 15 - i])

void pana_cs6_page_decoder::read_page()
{
    if (!buffer || (maxoffset - lastoffset < 16))
        ;
    pixelbuffer[0] = (wbuffer(0) << 6) | (wbuffer(1) >> 2); // 14 bit
    pixelbuffer[1] = (((wbuffer(1) & 0x3) << 12) | (wbuffer(2) << 4) | (wbuffer(3) >> 4)) & 0x3fff;
    pixelbuffer[2] = (wbuffer(3) >> 2) & 0x3;
    pixelbuffer[3] = ((wbuffer(3) & 0x3) << 8) | wbuffer(4);
    pixelbuffer[4] = (wbuffer(5) << 2) | (wbuffer(6) >> 6);
    pixelbuffer[5] = ((wbuffer(6) & 0x3f) << 4) | (wbuffer(7) >> 4);
    pixelbuffer[6] = (wbuffer(7) >> 2) & 0x3;
    pixelbuffer[7] = ((wbuffer(7) & 0x3) << 8) | wbuffer(8);
    pixelbuffer[8] = ((wbuffer(9) << 2) & 0x3fc) | (wbuffer(10) >> 6);
    pixelbuffer[9] = ((wbuffer(10) << 4) | (wbuffer(11) >> 4)) & 0x3ff;
    pixelbuffer[10] = (wbuffer(11) >> 2) & 0x3;
    pixelbuffer[11] = ((wbuffer(11) & 0x3) << 8) | wbuffer(12);
    pixelbuffer[12] = (((wbuffer(13) << 2) & 0x3fc) | wbuffer(14) >> 6) & 0x3ff;
    pixelbuffer[13] = ((wbuffer(14) << 4) | (wbuffer(15) >> 4)) & 0x3ff;
    current = 0;
    lastoffset += 16;
}

void pana_cs6_page_decoder::read_page12()
{
    if (!buffer || (maxoffset - lastoffset < 16))
        ;
    pixelbuffer[0] = (wbuffer(0) << 4) | (wbuffer(1) >> 4);              // 12 bit: 8/0 + 4 upper bits of /1
    pixelbuffer[1] = (((wbuffer(1) & 0xf) << 8) | (wbuffer(2))) & 0xfff; // 12 bit: 4l/1 + 8/2

    pixelbuffer[2] = (wbuffer(3) >> 6) & 0x3;                            // 2; 2u/3, 6 low bits remains in wbuffer(3)
    pixelbuffer[3] = ((wbuffer(3) & 0x3f) << 2) | (wbuffer(4) >> 6);     // 8; 6l/3 + 2u/4; 6 low bits remains in wbuffer(4)
    pixelbuffer[4] = ((wbuffer(4) & 0x3f) << 2) | (wbuffer(5) >> 6);     // 8: 6l/4 + 2u/5; 6 low bits remains in wbuffer(5)
    pixelbuffer[5] = ((wbuffer(5) & 0x3f) << 2) | (wbuffer(6) >> 6);     // 8: 6l/5 + 2u/6, 6 low bits remains in wbuffer(6)

    pixelbuffer[6] = (wbuffer(6) >> 4) & 0x3;                            // 2, 4 low bits remains in wbuffer(6)
    pixelbuffer[7] = ((wbuffer(6) & 0xf) << 4) | (wbuffer(7) >> 4);      // 8: 4 low bits from wbuffer(6), 4 upper bits from wbuffer(7)
    pixelbuffer[8] = ((wbuffer(7) & 0xf) << 4) | (wbuffer(8) >> 4);      // 8: 4 low bits from wbuffer(7), 4 upper bits from wbuffer(8)
    pixelbuffer[9] = ((wbuffer(8) & 0xf) << 4) | (wbuffer(9) >> 4);      // 8: 4 low bits from wbuffer(8), 4 upper bits from wbuffer(9)

    pixelbuffer[10] = (wbuffer(9) >> 2) & 0x3;                           // 2: bits 2-3 from wbuffer(9), two low bits remain in wbuffer(9)
    pixelbuffer[11] = ((wbuffer(9) & 0x3) << 6) | (wbuffer(10) >> 2);    // 8: 2 bits from wbuffer(9), 6 bits from wbuffer(10)
    pixelbuffer[12] = ((wbuffer(10) & 0x3) << 6) | (wbuffer(11) >> 2);   // 8: 2 bits from wbuffer(10), 6 bits from wbuffer(11)
    pixelbuffer[13] = ((wbuffer(11) & 0x3) << 6) | (wbuffer(12) >> 2);   // 8: 2 bits from wbuffer(11), 6 bits from wbuffer(12)

    pixelbuffer[14] = wbuffer(12) & 0x3;                                 // 2: low bits from wbuffer(12)
    pixelbuffer[15] = wbuffer(13);
    pixelbuffer[16] = wbuffer(14);
    pixelbuffer[17] = wbuffer(15);
    current = 0;
    lastoffset += 16;
}

#undef wbuffer

}

void DCraw::panasonic_load_raw()
{
    int enc_blck_size = RT_pana_info.bpp == 12 ? 10 : 9;
    if (RT_pana_info.encoding == 5) {
        pana_bits_t pana_bits(ifp, load_flags, RT_pana_info.encoding);
        pana_bits(0, 0);
        unsigned bytes[16] = {};
        for (int row = 0; row < raw_height; ++row) {
            ushort* raw_block_data = raw_image + row * raw_width;

            for (int col = 0; col < raw_width; col += enc_blck_size) {
                pana_bits(0, bytes);

                if (RT_pana_info.bpp == 12) {
                    raw_block_data[col] = ((bytes[1] & 0xF) << 8) + bytes[0];
                    raw_block_data[col + 1] = 16 * bytes[2] + (bytes[1] >> 4);
                    raw_block_data[col + 2] = ((bytes[4] & 0xF) << 8) + bytes[3];
                    raw_block_data[col + 3] = 16 * bytes[5] + (bytes[4] >> 4);
                    raw_block_data[col + 4] = ((bytes[7] & 0xF) << 8) + bytes[6];
                    raw_block_data[col + 5] = 16 * bytes[8] + (bytes[7] >> 4);
                    raw_block_data[col + 6] = ((bytes[10] & 0xF) << 8) + bytes[9];
                    raw_block_data[col + 7] = 16 * bytes[11] + (bytes[10] >> 4);
                    raw_block_data[col + 8] = ((bytes[13] & 0xF) << 8) + bytes[12];
                    raw_block_data[col + 9] = 16 * bytes[14] + (bytes[13] >> 4);
                }
                else if (RT_pana_info.bpp == 14) {
                    raw_block_data[col] = bytes[0] + ((bytes[1] & 0x3F) << 8);
                    raw_block_data[col + 1] = (bytes[1] >> 6) + 4 * (bytes[2]) + ((bytes[3] & 0xF) << 10);
                    raw_block_data[col + 2] = (bytes[3] >> 4) + 16 * (bytes[4]) + ((bytes[5] & 3) << 12);
                    raw_block_data[col + 3] = ((bytes[5] & 0xFC) >> 2) + (bytes[6] << 6);
                    raw_block_data[col + 4] = bytes[7] + ((bytes[8] & 0x3F) << 8);
                    raw_block_data[col + 5] = (bytes[8] >> 6) + 4 * bytes[9] + ((bytes[10] & 0xF) << 10);
                    raw_block_data[col + 6] = (bytes[10] >> 4) + 16 * bytes[11] + ((bytes[12] & 3) << 12);
                    raw_block_data[col + 7] = ((bytes[12] & 0xFC) >> 2) + (bytes[13] << 6);
                    raw_block_data[col + 8] = bytes[14] + ((bytes[15] & 0x3F) << 8);
                }
            }
        }
    } else if (RT_pana_info.encoding == 6) {
        panasonicC6_load_raw();
    } else if (RT_pana_info.encoding == 7) {
        panasonicC7_load_raw();
    } else if (RT_pana_info.encoding == 8) {
        panasonicC8_load_raw();
    } else {
        pana_bits_t pana_bits(ifp, load_flags, RT_pana_info.encoding);
        pana_bits(0, 0);
        int sh = 0, pred[2], nonz[2];
        for (int row = 0; row < height; ++row) {
            for (int col = 0; col < raw_width; ++col) {
                int i;
                if ((i = col % 14) == 0) {
                    pred[0] = pred[1] = nonz[0] = nonz[1] = 0;
                }
                if (i % 3 == 2) {
                    sh = 4 >> (3 - pana_bits(2));
                }
                if (nonz[i & 1]) {
                    int j;
                    if ((j = pana_bits(8))) {
                        if ((pred[i & 1] -= 0x80 << sh) < 0 || sh == 4) {
                            pred[i & 1] &= ~(-1 << sh);
                        }
                        pred[i & 1] += j << sh;
                    }
                } else if ((nonz[i & 1] = pana_bits(8)) || i > 11) {
                    pred[i & 1] = nonz[i & 1] << 4 | pana_bits(4);
                }
                if ((raw_image[(row)*raw_width+(col)] = pred[col & 1]) > 4098 && col < width) {
                    derror();
                }
            }
        }
    }
}

void DCraw::panasonicC6_load_raw()
{
    constexpr int rowstep = 16;
    const bool _12bit = RT_pana_info.bpp == 12;
    const int pixperblock = _12bit ? 14 : 11;
    const int blocksperrow = raw_width / pixperblock;
    const int rowbytes = blocksperrow * 16;
    const unsigned pixelbase0 = _12bit ? 0x80 : 0x200;
    const unsigned pixelbase_compare = _12bit ? 0x800 : 0x2000;
    const unsigned spix_compare = _12bit ? 0x3fff : 0xffff;
    const unsigned pixel_mask = _12bit ? 0xfff : 0x3fff;
    unsigned char *iobuf = (unsigned char *)malloc(rowbytes * rowstep);
    merror(iobuf, "panasonicC6_load_raw()");

    for (int row = 0; row < raw_height - rowstep + 1; row += rowstep) {
        const int rowstoread = MIN(rowstep, raw_height - row);
        fread(iobuf, rowbytes, rowstoread, ifp);
        pana_cs6_page_decoder page(iobuf, rowbytes * rowstoread);
        for (int crow = 0, col = 0; crow < rowstoread; ++crow, col = 0) {
            unsigned short *rowptr = &raw_image[(row + crow) * raw_width];
            for (int rblock = 0; rblock < blocksperrow; rblock++) {
                if (_12bit)
                    page.read_page12();
                else
                    page.read_page();
                unsigned oddeven[2] = {0, 0}, nonzero[2] = {0, 0};
                unsigned pmul = 0, pixel_base = 0;
                for (int pix = 0; pix < pixperblock; ++pix) {
                    if (pix % 3 == 2) {
                        unsigned base = _12bit ? page.nextpixel12(): page.nextpixel();
                        if (base > 3) {
                            derror();
                        }
                        if (base == 3) {
                            base = 4;
                        }
                        pixel_base = pixelbase0 << base;
                        pmul = 1 << base;
                    }
                    unsigned epixel = _12bit ? page.nextpixel12() : page.nextpixel();
                    if (oddeven[pix % 2]) {
                        epixel *= pmul;
                        if (pixel_base < pixelbase_compare && nonzero[pix % 2] > pixel_base) {
                            epixel += nonzero[pix % 2] - pixel_base;
                        }
                        nonzero[pix % 2] = epixel;
                    } else {
                        oddeven[pix % 2] = epixel;
                        if (epixel) {
                            nonzero[pix % 2] = epixel;
                        } else {
                            epixel = nonzero[pix % 2];
                        }
                    }
                    const unsigned spix = epixel - 0xf;
                    if (spix <= spix_compare) {
                        rowptr[col++] = spix & spix_compare;
                    } else {
                        epixel = (((signed int)(epixel + 0x7ffffff1)) >> 0x1f);
                        rowptr[col++] = epixel & pixel_mask;
                    }
                }
            }
        }
    }
    free(iobuf);
    tiff_bps = RT_pana_info.bpp;
}

void DCraw::panasonicC7_load_raw()
{
    constexpr int rowstep = 16;
    const int pixperblock = RT_pana_info.bpp == 14 ? 9 : 10;
    const int rowbytes = raw_width / pixperblock * 16;

    unsigned char *iobuf = (unsigned char *)malloc(rowbytes * rowstep);
    merror(iobuf, "panasonicC7_load_raw()");
    for (int row = 0; row < raw_height - rowstep + 1; row += rowstep) {
        const int rowstoread = MIN(rowstep, raw_height - row);
        fread (iobuf, rowbytes, rowstoread, ifp);
        unsigned char *bytes = iobuf;
        for (int crow = 0; crow < rowstoread; crow++) {
            ushort *rowptr = &raw_image[(row + crow) * raw_width];
            for (int col = 0; col < raw_width - pixperblock + 1; col += pixperblock, bytes += 16) {
                if (RT_pana_info.bpp == 14) {
                    rowptr[col] = bytes[0] + ((bytes[1] & 0x3F) << 8);
                    rowptr[col + 1] = (bytes[1] >> 6) + 4 * (bytes[2]) + ((bytes[3] & 0xF) << 10);
                    rowptr[col + 2] = (bytes[3] >> 4) + 16 * (bytes[4]) + ((bytes[5] & 3) << 12);
                    rowptr[col + 3] = ((bytes[5] & 0xFC) >> 2) + (bytes[6] << 6);
                    rowptr[col + 4] = bytes[7] + ((bytes[8] & 0x3F) << 8);
                    rowptr[col + 5] = (bytes[8] >> 6) + 4 * bytes[9] + ((bytes[10] & 0xF) << 10);
                    rowptr[col + 6] = (bytes[10] >> 4) + 16 * bytes[11] + ((bytes[12] & 3) << 12);
                    rowptr[col + 7] = ((bytes[12] & 0xFC) >> 2) + (bytes[13] << 6);
                    rowptr[col + 8] = bytes[14] + ((bytes[15] & 0x3F) << 8);
                } else if (RT_pana_info.bpp == 12) { // have not seen in the wild yet
                    rowptr[col] = ((bytes[1] & 0xF) << 8) + bytes[0];
                    rowptr[col + 1] = 16 * bytes[2] + (bytes[1] >> 4);
                    rowptr[col + 2] = ((bytes[4] & 0xF) << 8) + bytes[3];
                    rowptr[col + 3] = 16 * bytes[5] + (bytes[4] >> 4);
                    rowptr[col + 4] = ((bytes[7] & 0xF) << 8) + bytes[6];
                    rowptr[col + 5] = 16 * bytes[8] + (bytes[7] >> 4);
                    rowptr[col + 6] = ((bytes[10] & 0xF) << 8) + bytes[9];
                    rowptr[col + 7] = 16 * bytes[11] + (bytes[10] >> 4);
                    rowptr[col + 8] = ((bytes[13] & 0xF) << 8) + bytes[12];
                    rowptr[col + 9] = 16 * bytes[14] + (bytes[13] >> 4);
                }
            }
        }
    }
    free(iobuf);
    tiff_bps = RT_pana_info.bpp;
}

void DCraw::panasonicC8_load_raw()
{
    int errs = 0;
    unsigned totalw = 0;

    if (RT_pana_info.v8tags.stripe_count > 5) errs++;
    for (int i = 0; i < RT_pana_info.v8tags.stripe_count && i < 5; i++) {
        if (RT_pana_info.v8tags.stripe_height[i] != raw_height)
            errs++;
        if (RT_pana_info.v8tags.stripe_offsets[i] < 0 || (RT_pana_info.v8tags.stripe_offsets[i] + INT64((RT_pana_info.v8tags.stripe_compressed_size[i] + 7u) / 8u)) > INT64(ifp->size))
            errs++;
        totalw += RT_pana_info.v8tags.stripe_width[i];
    }
    if (totalw != raw_width) errs++;

    if (errs)
        derror();

    pana8_param_t pana8_param(RT_pana_info.v8tags);
    pana8_decode_loop(&pana8_param);
}

void DCraw::pana8_decode_loop(void *data)
{
#ifdef _OPENMP
    int errs = 0, scount = MIN(5, RT_pana_info.v8tags.stripe_count);
#pragma omp parallel for
    for (int stream = 0; stream < scount; stream++) {
        if (!pana8_decode_strip(data, stream))
            errs++;
    }
    if (errs)
        derror();
#else
    for (int stream = 0; stream < RT_pana_info.v8tags.stripe_count && stream < 5; stream++)
        if (!pana8_decode_strip(data, stream))
            derror();
#endif
}

bool DCraw::pana8_decode_strip(void *data, int stream)
{
    pana8_param_t *pana8_param = (pana8_param_t *)data;
    if (!data || stream < 0 || stream > 4 || stream > RT_pana_info.v8tags.stripe_count) return 1; // error

    unsigned exactbytes = (RT_pana_info.v8tags.stripe_compressed_size[stream] + 7u) / 8u;
    pana8_bufio_t bufio(ifp, RT_pana_info.v8tags.stripe_offsets[stream], exactbytes);
    return pana8_param->DecodeC8(bufio, RT_pana_info.v8tags.stripe_width[stream],
        RT_pana_info.v8tags.stripe_height[stream], raw_image, raw_width, raw_height,
        RT_pana_info.v8tags.stripe_left[stream]);
}