/*
Open Asset Import Library (assimp)
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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
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* Neither the name of the assimp team, nor the names of its
  contributors may be used to endorse or promote products
  derived from this software without specific prior
  written permission of the assimp team.

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*/

/** @file  STEPFileEncoding.cpp
 *  @brief STEP character handling, string unescaping
 */
#include "AssimpPCH.h"
#include "STEPFileEncoding.h"
#include "fast_atof.h"

#include "../contrib/ConvertUTF/ConvertUTF.h"

using namespace Assimp;

// roman1 to utf16 table
static const UTF16 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 UTF32 unival = mac_codetable[macval - 0x20], *univalp = &unival;

				UTF8 temp[5], *tempp = temp;
				ai_assert(sizeof(UTF8) == 1);

				if(ConvertUTF32toUTF8(&univalp, univalp+1, &tempp, tempp+sizeof(temp), lenientConversion) != conversionOK) {
					return false;
				}

				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()-4;						

						for (; j < jend; ++j) {
							if (s[j] == '\\' && s[j] == 'X' && s[j] == '0' && s[j] == '\\') {
								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;
							boost::scoped_array<UTF16> src(new UTF16[count]);

							const char* cur = s.c_str() + basei;
							for (size_t k = 0; k < count; ++k, cur += 4) {
								src[k] = (static_cast<UTF16>(HexOctetToDecimal(cur)) << 8u)  |
									 static_cast<UTF16>(HexOctetToDecimal(cur+2));
							}

							const size_t dcount = count * 3; // this is enough to hold all possible outputs
							boost::scoped_array<UTF8> dest(new UTF8[dcount]);

							const UTF16* srct = src.get();
							UTF8* destt = dest.get();
							if(ConvertUTF16toUTF8(&srct, srct+count, &destt, destt+dcount, lenientConversion) != conversionOK) {
								return false;
							}

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

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

							ai_assert(sizeof(UTF8) == 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;
							boost::scoped_array<UTF32> src(new UTF32[count]);

							const char* cur = s.c_str() + basei;
							for (size_t k = 0; k < count; ++k, cur += 8) {
								src[k] = (static_cast<UTF32>(HexOctetToDecimal(cur  )) << 24u) |
									     (static_cast<UTF32>(HexOctetToDecimal(cur+2)) << 16u) |
										 (static_cast<UTF32>(HexOctetToDecimal(cur+4)) << 8u)  |
									     (static_cast<UTF32>(HexOctetToDecimal(cur+6)));
							}

							const size_t dcount = count * 5; // this is enough to hold all possible outputs
							boost::scoped_array<UTF8> dest(new UTF8[dcount]);

							const UTF32* srct = src.get();
							UTF8* destt = dest.get();
							if(ConvertUTF32toUTF8(&srct, srct+count, &destt, destt+dcount, lenientConversion) != conversionOK) {
								return false;
							}

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

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

							ai_assert(sizeof(UTF8) == 1);
							s.insert(i, reinterpret_cast<char*>(dest.get()), outcount);

							i += outcount;
							continue;
						}
					}				

					break;
					
					// TODO: other encoding patterns?

				default:
					return false;
				}
			}
		}
		++i;
	}
	return true;
}
