/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include "bladerunner/adpcm_decoder.h"

#include "common/endian.h"
#include "common/util.h"

namespace BladeRunner {

static const
int16 imaIndexTable[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };

static const
uint16 imaStepTable[712] = {
 0x0000,0x0001,0x0003,0x0004,0x0007,0x0008,0x000a,0x000b,
 0x0001,0x0003,0x0005,0x0007,0x0009,0x000b,0x000d,0x000f,
 0x0001,0x0003,0x0005,0x0007,0x000a,0x000c,0x000e,0x0010,
 0x0001,0x0003,0x0006,0x0008,0x000b,0x000d,0x0010,0x0012,
 0x0001,0x0003,0x0006,0x0008,0x000c,0x000e,0x0011,0x0013,
 0x0001,0x0004,0x0007,0x000a,0x000d,0x0010,0x0013,0x0016,
 0x0001,0x0004,0x0007,0x000a,0x000e,0x0011,0x0014,0x0017,
 0x0001,0x0004,0x0008,0x000b,0x000f,0x0012,0x0016,0x0019,
 0x0002,0x0006,0x000a,0x000e,0x0012,0x0016,0x001a,0x001e,
 0x0002,0x0006,0x000a,0x000e,0x0013,0x0017,0x001b,0x001f,
 0x0002,0x0006,0x000b,0x000f,0x0015,0x0019,0x001e,0x0022,
 0x0002,0x0007,0x000c,0x0011,0x0017,0x001c,0x0021,0x0026,
 0x0002,0x0007,0x000d,0x0012,0x0019,0x001e,0x0024,0x0029,
 0x0003,0x0009,0x000f,0x0015,0x001c,0x0022,0x0028,0x002e,
 0x0003,0x000a,0x0011,0x0018,0x001f,0x0026,0x002d,0x0034,
 0x0003,0x000a,0x0012,0x0019,0x0022,0x0029,0x0031,0x0038,
 0x0004,0x000c,0x0015,0x001d,0x0026,0x002e,0x0037,0x003f,
 0x0004,0x000d,0x0016,0x001f,0x0029,0x0032,0x003b,0x0044,
 0x0005,0x000f,0x0019,0x0023,0x002e,0x0038,0x0042,0x004c,
 0x0005,0x0010,0x001b,0x0026,0x0032,0x003d,0x0048,0x0053,
 0x0006,0x0012,0x001f,0x002b,0x0038,0x0044,0x0051,0x005d,
 0x0006,0x0013,0x0021,0x002e,0x003d,0x004a,0x0058,0x0065,
 0x0007,0x0016,0x0025,0x0034,0x0043,0x0052,0x0061,0x0070,
 0x0008,0x0018,0x0029,0x0039,0x004a,0x005a,0x006b,0x007b,
 0x0009,0x001b,0x002d,0x003f,0x0052,0x0064,0x0076,0x0088,
 0x000a,0x001e,0x0032,0x0046,0x005a,0x006e,0x0082,0x0096,
 0x000b,0x0021,0x0037,0x004d,0x0063,0x0079,0x008f,0x00a5,
 0x000c,0x0024,0x003c,0x0054,0x006d,0x0085,0x009d,0x00b5,
 0x000d,0x0027,0x0042,0x005c,0x0078,0x0092,0x00ad,0x00c7,
 0x000e,0x002b,0x0049,0x0066,0x0084,0x00a1,0x00bf,0x00dc,
 0x0010,0x0030,0x0051,0x0071,0x0092,0x00b2,0x00d3,0x00f3,
 0x0011,0x0034,0x0058,0x007b,0x00a0,0x00c3,0x00e7,0x010a,
 0x0013,0x003a,0x0061,0x0088,0x00b0,0x00d7,0x00fe,0x0125,
 0x0015,0x0040,0x006b,0x0096,0x00c2,0x00ed,0x0118,0x0143,
 0x0017,0x0046,0x0076,0x00a5,0x00d5,0x0104,0x0134,0x0163,
 0x001a,0x004e,0x0082,0x00b6,0x00eb,0x011f,0x0153,0x0187,
 0x001c,0x0055,0x008f,0x00c8,0x0102,0x013b,0x0175,0x01ae,
 0x001f,0x005e,0x009d,0x00dc,0x011c,0x015b,0x019a,0x01d9,
 0x0022,0x0067,0x00ad,0x00f2,0x0139,0x017e,0x01c4,0x0209,
 0x0026,0x0072,0x00bf,0x010b,0x0159,0x01a5,0x01f2,0x023e,
 0x002a,0x007e,0x00d2,0x0126,0x017b,0x01cf,0x0223,0x0277,
 0x002e,0x008a,0x00e7,0x0143,0x01a1,0x01fd,0x025a,0x02b6,
 0x0033,0x0099,0x00ff,0x0165,0x01cb,0x0231,0x0297,0x02fd,
 0x0038,0x00a8,0x0118,0x0188,0x01f9,0x0269,0x02d9,0x0349,
 0x003d,0x00b8,0x0134,0x01af,0x022b,0x02a6,0x0322,0x039d,
 0x0044,0x00cc,0x0154,0x01dc,0x0264,0x02ec,0x0374,0x03fc,
 0x004a,0x00df,0x0175,0x020a,0x02a0,0x0335,0x03cb,0x0460,
 0x0052,0x00f6,0x019b,0x023f,0x02e4,0x0388,0x042d,0x04d1,
 0x005a,0x010f,0x01c4,0x0279,0x032e,0x03e3,0x0498,0x054d,
 0x0063,0x012a,0x01f1,0x02b8,0x037f,0x0446,0x050d,0x05d4,
 0x006d,0x0148,0x0223,0x02fe,0x03d9,0x04b4,0x058f,0x066a,
 0x0078,0x0168,0x0259,0x0349,0x043b,0x052b,0x061c,0x070c,
 0x0084,0x018d,0x0296,0x039f,0x04a8,0x05b1,0x06ba,0x07c3,
 0x0091,0x01b4,0x02d8,0x03fb,0x051f,0x0642,0x0766,0x0889,
 0x00a0,0x01e0,0x0321,0x0461,0x05a2,0x06e2,0x0823,0x0963,
 0x00b0,0x0210,0x0371,0x04d1,0x0633,0x0793,0x08f4,0x0a54,
 0x00c2,0x0246,0x03ca,0x054e,0x06d2,0x0856,0x09da,0x0b5e,
 0x00d5,0x027f,0x042a,0x05d4,0x0780,0x092a,0x0ad5,0x0c7f,
 0x00ea,0x02bf,0x0495,0x066a,0x0840,0x0a15,0x0beb,0x0dc0,
 0x0102,0x0306,0x050b,0x070f,0x0914,0x0b18,0x0d1d,0x0f21,
 0x011c,0x0354,0x058c,0x07c4,0x09fc,0x0c34,0x0e6c,0x10a4,
 0x0138,0x03a8,0x0619,0x0889,0x0afb,0x0d6b,0x0fdc,0x124c,
 0x0157,0x0406,0x06b5,0x0964,0x0c14,0x0ec3,0x1172,0x1421,
 0x017a,0x046e,0x0762,0x0a56,0x0d4a,0x103e,0x1332,0x1626,
 0x019f,0x04de,0x081e,0x0b5d,0x0e9e,0x11dd,0x151d,0x185c,
 0x01c9,0x055c,0x08ef,0x0c82,0x1015,0x13a8,0x173b,0x1ace,
 0x01f7,0x05e5,0x09d4,0x0dc2,0x11b1,0x159f,0x198e,0x1d7c,
 0x0229,0x067c,0x0acf,0x0f22,0x1375,0x17c8,0x1c1b,0x206e,
 0x0260,0x0721,0x0be3,0x10a4,0x1567,0x1a28,0x1eea,0x23ab,
 0x029d,0x07d8,0x0d14,0x124f,0x178b,0x1cc6,0x2202,0x273d,
 0x02e0,0x08a1,0x0e63,0x1424,0x19e6,0x1fa7,0x2569,0x2b2a,
 0x032a,0x097f,0x0fd4,0x1629,0x1c7e,0x22d3,0x2928,0x2f7d,
 0x037b,0x0a72,0x1169,0x1860,0x1f57,0x264e,0x2d45,0x343c,
 0x03d4,0x0b7d,0x1326,0x1acf,0x2279,0x2a22,0x31cb,0x3974,
 0x0436,0x0ca3,0x1511,0x1d7e,0x25ec,0x2e59,0x36c7,0x3f34,
 0x04a2,0x0de7,0x172c,0x2071,0x29b7,0x32fc,0x3c41,0x4586,
 0x0519,0x0f4b,0x197e,0x23b0,0x2de3,0x3815,0x4248,0x4c7a,
 0x059b,0x10d2,0x1c0a,0x2741,0x327a,0x3db1,0x48e9,0x5420,
 0x062b,0x1281,0x1ed8,0x2b2e,0x3786,0x43dc,0x5033,0x5c89,
 0x06c9,0x145b,0x21ee,0x2f80,0x3d14,0x4aa6,0x5839,0x65cb,
 0x0777,0x1665,0x2553,0x3441,0x4330,0x521e,0x610c,0x6ffa,
 0x0836,0x18a2,0x290f,0x397b,0x49e8,0x5a54,0x6ac1,0x7b2d,
 0x0908,0x1b19,0x2d2a,0x3f3b,0x514c,0x635d,0x756e,0x877f,
 0x09ef,0x1dce,0x31ae,0x458d,0x596d,0x6d4c,0x812c,0x950b,
 0x0aee,0x20ca,0x36a6,0x4c82,0x625f,0x783b,0x8e17,0xa3f3,
 0x0c05,0x2410,0x3c1c,0x5427,0x6c34,0x843f,0x9c4b,0xb456,
 0x0d39,0x27ac,0x4220,0x5c93,0x7707,0x917a,0xabee,0xc661,
 0x0e8c,0x2ba4,0x48bd,0x65d5,0x82ee,0xa006,0xbd1f,0xda37,
 0x0fff,0x2ffe,0x4ffe,0x6ffd,0x8ffe,0xaffd,0xcffd,0xeffc
};

void ADPCMWestwoodDecoder::decode(uint8 *in, size_t size, int16 *out, bool forceLittleEndianOut) {
	uint8 *end = in + size;

	int16 stepIndex = _stepIndex;
	int32 predictor = _predictor;

	while (in != end) {
		uint16 bl = *in++;

		for (int n = 0; n != 2; ++n) {
			uint8 nibble = (bl >> (4 * n)) & 0x0f;
			uint8 code = nibble & 0x07;
			uint8 sign = nibble & 0x08;

			int diff = imaStepTable[(stepIndex << 3) | code];

			// Westwood's IMA ADPCM differs from the below standard implementation
			// in the LSB in a couple of places.
			//int diff = imaStepTable_std[stepIndex] * code / 4 + imaStepTable_std[stepIndex] / 8;

			if (sign)
				predictor -= diff;
			else
				predictor += diff;

			predictor = CLIP<int32>(predictor, -32768, 32767);

			if (out) {
				if (forceLittleEndianOut) {
					// Bugfix:
					// enforce "little-endian" type of output for VQA audio stream
					// This is needed for Big Endian platforms to behave correctly in raw audio streams in VQA videos
					// because in VQADecoder::VQAAudioTrack::decodeAudioFrame() a raw stream is created for the audio
					// with the explicit flag: FLAG_LITTLE_ENDIAN
					WRITE_LE_INT16(out++, (int16)predictor);
				} else {
					*out++ = (int16)predictor;
				}
			}
			stepIndex = imaIndexTable[code] + stepIndex;
			stepIndex = CLIP<int16>(stepIndex, 0, 88);
		}
	}

	_stepIndex = stepIndex;
	_predictor = predictor;
}

} // End of namespace BladeRunner