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*/

/** @file  STEPFileEncoding.cpp

 *  @brief STEP character handling, string un-escaping

 */

#include "STEPFileEncoding.h"

#include <assimp/fast_atof.h>

#include "utf8.h"

#include <memory>

using namespace Assimp;

// roman1 to utf16 table

static const uint16_t mac_codetable[] = {

    // 0x20 unassig./nonprint. slots

     0x0020 ,

     0x0021 ,

     0x0022 ,

     0x0023 ,

     0x0024 ,

     0x0025 ,

     0x0026 ,

     0x0027 ,

     0x0028 ,

     0x0029 ,

     0x002A ,

     0x002B ,

     0x002C ,

     0x002D ,

     0x002E ,

     0x002F ,

     0x0030 ,

     0x0031 ,

     0x0032 ,

     0x0033 ,

     0x0034 ,

     0x0035 ,

     0x0036 ,

     0x0037 ,

     0x0038 ,

     0x0039 ,

     0x003A ,

     0x003B ,

     0x003C ,

     0x003D ,

     0x003E ,

     0x003F ,

     0x0040 ,

     0x0041 ,

     0x0042 ,

     0x0043 ,

     0x0044 ,

     0x0045 ,

     0x0046 ,

     0x0047 ,

     0x0048 ,

     0x0049 ,

     0x004A ,

     0x004B ,

     0x004C ,

     0x004D ,

     0x004E ,

     0x004F ,

     0x0050 ,

     0x0051 ,

     0x0052 ,

     0x0053 ,

     0x0054 ,

     0x0055 ,

     0x0056 ,

     0x0057 ,

     0x0058 ,

     0x0059 ,

     0x005A ,

     0x005B ,

     0x005C ,

     0x005D ,

     0x005E ,

     0x005F ,

     0x0060 ,

     0x0061 ,

     0x0062 ,

     0x0063 ,

     0x0064 ,

     0x0065 ,

     0x0066 ,

     0x0067 ,

     0x0068 ,

     0x0069 ,

     0x006A ,

     0x006B ,

     0x006C ,

     0x006D ,

     0x006E ,

     0x006F ,

     0x0070 ,

     0x0071 ,

     0x0072 ,

     0x0073 ,

     0x0074 ,

     0x0075 ,

     0x0076 ,

     0x0077 ,

     0x0078 ,

     0x0079 ,

     0x007A ,

     0x007B ,

     0x007C ,

     0x007D ,

     0x007E ,

     0x0000 , // unassig.

     0x00C4 ,

     0x00C5 ,

     0x00C7 ,

     0x00C9 ,

     0x00D1 ,

     0x00D6 ,

     0x00DC ,

     0x00E1 ,

     0x00E0 ,

     0x00E2 ,

     0x00E4 ,

     0x00E3 ,

     0x00E5 ,

     0x00E7 ,

     0x00E9 ,

     0x00E8 ,

     0x00EA ,

     0x00EB ,

     0x00ED ,

     0x00EC ,

     0x00EE ,

     0x00EF ,

     0x00F1 ,

     0x00F3 ,

     0x00F2 ,

     0x00F4 ,

     0x00F6 ,

     0x00F5 ,

     0x00FA ,

     0x00F9 ,

     0x00FB ,

     0x00FC ,

     0x2020 ,

     0x00B0 ,

     0x00A2 ,

     0x00A3 ,

     0x00A7 ,

     0x2022 ,

     0x00B6 ,

     0x00DF ,

     0x00AE ,

     0x00A9 ,

     0x2122 ,

     0x00B4 ,

     0x00A8 ,

     0x2260 ,

     0x00C6 ,

     0x00D8 ,

     0x221E ,

     0x00B1 ,

     0x2264 ,

     0x2265 ,

     0x00A5 ,

     0x00B5 ,

     0x2202 ,

     0x2211 ,

     0x220F ,

     0x03C0 ,

     0x222B ,

     0x00AA ,

     0x00BA ,

     0x03A9 ,

     0x00E6 ,

     0x00F8 ,

     0x00BF ,

     0x00A1 ,

     0x00AC ,

     0x221A ,

     0x0192 ,

     0x2248 ,

     0x2206 ,

     0x00AB ,

     0x00BB ,

     0x2026 ,

     0x00A0 ,

     0x00C0 ,

     0x00C3 ,

     0x00D5 ,

     0x0152 ,

     0x0153 ,

     0x2013 ,

     0x2014 ,

     0x201C ,

     0x201D ,

     0x2018 ,

     0x2019 ,

     0x00F7 ,

     0x25CA ,

     0x00FF ,

     0x0178 ,

     0x2044 ,

     0x20AC ,

     0x2039 ,

     0x203A ,

     0xFB01 ,

     0xFB02 ,

     0x2021 ,

     0x00B7 ,

     0x201A ,

     0x201E ,

     0x2030 ,

     0x00C2 ,

     0x00CA ,

     0x00C1 ,

     0x00CB ,

     0x00C8 ,

     0x00CD ,

     0x00CE ,

     0x00CF ,

     0x00CC ,

     0x00D3 ,

     0x00D4 ,

     0xF8FF ,

     0x00D2 ,

     0x00DA ,

     0x00DB ,

     0x00D9 ,

     0x0131 ,

     0x02C6 ,

     0x02DC ,

     0x00AF ,

     0x02D8 ,

     0x02D9 ,

     0x02DA ,

     0x00B8 ,

     0x02DD ,

     0x02DB ,

     0x02C7

};

// ------------------------------------------------------------------------------------------------

bool STEP::StringToUTF8(std::string& s)

{

    // very basic handling for escaped string sequences

    // http://doc.spatial.com/index.php?title=InterOp:Connect/STEP&redirect=no

    for (size_t i = 0; i < s.size(); ) {

        if (s[i] == '\\') {

            // \S\X - cp1252 (X is the character remapped to [0,127])

            if (i+3 < s.size() && s[i+1] == 'S' && s[i+2] == '\\') {

                // http://stackoverflow.com/questions/5586214/how-to-convert-char-from-iso-8859-1-to-utf-8-in-c-multiplatformly

                ai_assert((uint8_t)s[i+3] < 0x80);

                const uint8_t ch = s[i+3] + 0x80;

                s[i] = 0xc0 | (ch & 0xc0) >> 6;

                s[i+1] =  0x80 | (ch & 0x3f);

                s.erase(i + 2,2);

                ++i;

            }

            // \X\xx - mac/roman (xx is a hex sequence)

            else if (i+4 < s.size() && s[i+1] == 'X' && s[i+2] == '\\') {

                const uint8_t macval = HexOctetToDecimal(s.c_str() + i + 3);

                if(macval < 0x20) {

                    return false;

                }

                ai_assert(sizeof(mac_codetable) / sizeof(mac_codetable[0]) == 0x100-0x20);

                const uint32_t unival = mac_codetable[macval - 0x20], *univalp = &unival;

                unsigned char temp[5], *tempp = temp;

                ai_assert(sizeof( unsigned char ) == 1);

                utf8::utf32to8( univalp, univalp + 1, tempp );

                const size_t outcount = static_cast<size_t>(tempp-temp);

                s.erase(i,5);

                s.insert(i, reinterpret_cast<char*>(temp), outcount);

                i += outcount;

            }

            // \Xn\ .. \X0\ - various unicode encodings (n=2: utf16; n=4: utf32)

            else if (i+3 < s.size() && s[i+1] == 'X' && s[i+2] >= '0' && s[i+2] <= '9') {

                switch(s[i+2]) {

                    // utf16

                case '2':

                    // utf32

                case '4':

                    if (s[i+3] == '\\') {

                        const size_t basei = i+4;

                        size_t j = basei, jend = s.size()-3;

                        for (; j < jend; ++j) {

                            if (s[j] == '\\' && s[j+1] == 'X' && s[j+2] == '0' && s[j+3] == '\\') {

                                break;

                            }

                        }

                        if (j == jend) {

                            return false;

                        }

                        if (j == basei) {

                            s.erase(i,8);

                            continue;

                        }

                        if (s[i+2] == '2') {

                            if (((j - basei) % 4) != 0) {

                                return false;

                            }

                            const size_t count = (j-basei)/4;

                            std::unique_ptr<uint16_t[]> src(new uint16_t[count]);

                            const char* cur = s.c_str() + basei;

                            for (size_t k = 0; k < count; ++k, cur += 4) {

                                src[k] = (static_cast<uint16_t>(HexOctetToDecimal(cur)) << 8u)  |

                                     static_cast<uint16_t>(HexOctetToDecimal(cur+2));

                            }

                            const size_t dcount = count * 3; // this is enough to hold all possible outputs

                            std::unique_ptr<unsigned char[]> dest(new unsigned char[dcount]);

                            const uint16_t* srct = src.get();

                            unsigned char* destt = dest.get();

                            utf8::utf16to8( srct, srct + count, destt );

                            const size_t outcount = static_cast<size_t>(destt-dest.get());

                            s.erase(i,(j+4-i));

                            ai_assert(sizeof(unsigned char) == 1);

                            s.insert(i, reinterpret_cast<char*>(dest.get()), outcount);

                            i += outcount;

                            continue;

                        }

                        else if (s[i+2] == '4') {

                            if (((j - basei) % 8) != 0) {

                                return false;

                            }

                            const size_t count = (j-basei)/8;

                            std::unique_ptr<uint32_t[]> src(new uint32_t[count]);

                            const char* cur = s.c_str() + basei;

                            for (size_t k = 0; k < count; ++k, cur += 8) {

                                src[k] = (static_cast<uint32_t>(HexOctetToDecimal(cur  )) << 24u) |

                                         (static_cast<uint32_t>(HexOctetToDecimal(cur+2)) << 16u) |

                                         (static_cast<uint32_t>(HexOctetToDecimal(cur+4)) << 8u)  |

                                         (static_cast<uint32_t>(HexOctetToDecimal(cur+6)));

                            }

                            const size_t dcount = count * 5; // this is enough to hold all possible outputs

                            std::unique_ptr<unsigned char[]> dest(new unsigned char[dcount]);

                            const uint32_t* srct = src.get();

                            unsigned char* destt = dest.get();

                            utf8::utf32to8( srct, srct + count, destt );

                            const size_t outcount = static_cast<size_t>(destt-dest.get());

                            s.erase(i,(j+4-i));

                            ai_assert(sizeof(unsigned char) == 1);

                            s.insert(i, reinterpret_cast<char*>(dest.get()), outcount);

                            i += outcount;

                            continue;

                        }

                    }

                    break;

                    // TODO: other encoding patterns?

                default:

                    return false;

                }

            }

        }

        ++i;

    }

    return true;

}