/* 31-sample MOD loader (Amiga, PC, etc.)**** Note: Data sanitation is done in the last stage** of module loading, so you don't need to do that here.*/ #include <stdio.h>#include <stdlib.h>#include <string.h>#include <ctype.h> // isdigit()#include <stdint.h>#include <stdbool.h>#include "../pt2_header.h"#include "../pt2_paula.h" // PAULA_VOICES#include "../pt2_config.h"#include "../pt2_structs.h"#include "../pt2_replayer.h"#include "../pt2_textout.h"#include "../pt2_visuals.h" enum // 31-sample .MOD types{	FORMAT_UNKNOWN, 	FORMAT_PT,  // ProTracker or compatible	FORMAT_FLT, // Startrekker (4 channels)	FORMAT_FT2, // FT2 (or other trackers, multichannel)	FORMAT_NT,  // NoiseTracker	FORMAT_HMNT // His Master's NoiseTracker (special one)}; static int32_t realSampleLengths[MOD_SAMPLES]; static uint8_t getMod31Type(uint8_t *buffer, uint32_t filesize, uint8_t *numChannels); // 0 = not detectedbool detectMod31(uint8_t *buffer, uint32_t filesize); module_t *loadMod31(uint8_t *buffer, uint32_t filesize){	module_t *m = createEmptyMod();	if (m == NULL)	{		statusOutOfMemory();		goto loadError;	} 	uint8_t numChannels;	uint8_t modFormat = getMod31Type(buffer, filesize, &numChannels);	if (modFormat == FORMAT_UNKNOWN || numChannels > PAULA_VOICES)	{		displayErrorMsg("UNSUPPORTED MOD !");		goto loadError;	} 	uint8_t *p = buffer; 	memcpy(m->header.name, p, 20); p += 20; 	// read sample headers	moduleSample_t *s = m->samples;	for (int32_t i = 0; i < MOD_SAMPLES; i++, s++)	{		memcpy(s->text, p, 22); p += 22; 		realSampleLengths[i] = ((p[0] << 8) | p[1]) * 2; p += 2;		s->length = (realSampleLengths[i] > config.maxSampleLength) ? config.maxSampleLength : realSampleLengths[i]; 		s->fineTune = *p++ & 0xF;		s->volume = *p++; 		s->loopStart = ((p[0] << 8) | p[1]) * 2; p += 2;		s->loopLength = ((p[0] << 8) | p[1]) * 2; p += 2; 		// fix for poorly converted STK (< v2.5) -> PT/NT modules		if (s->loopLength > 2 && s->loopStart+s->loopLength > s->length)		{			if ((s->loopStart/2) + s->loopLength <= s->length)				s->loopStart /= 2;		}	} 	m->header.songLength = *p++;	p++; // skip uninteresting field (127 in PT MOds, "restart pos" in PC MODs) 	if (modFormat == FORMAT_PT && m->header.songLength == 129)		m->header.songLength = 127; // fixes a specific copy of beatwave.mod (XXX: hackish...) 	if (m->header.songLength == 0 || m->header.songLength > 129)	{		displayErrorMsg("NOT A MOD FILE !");		goto loadError;	} 	// read orders and count number of patterns	int32_t numPatterns = 0;	for (int32_t i = 0; i < 128; i++)	{		m->header.patternTable[i] = *p++;		if (m->header.patternTable[i] > numPatterns)			numPatterns = m->header.patternTable[i];	}	numPatterns++; 	if (numPatterns > MAX_PATTERNS)	{		displayErrorMsg("UNSUPPORTED MOD !");		goto loadError;	} 	p += 4; // skip magic ID (already handled) 	// load pattern data	for (int32_t i = 0; i < numPatterns; i++)	{		note_t *note = m->patterns[i];		for (int32_t j = 0; j < MOD_ROWS; j++)		{			for (int32_t k = 0; k < numChannels; k++, note++, p += 4)			{				note->period = ((p[0] & 0x0F) << 8) | p[1];				note->sample = ((p[0] & 0xF0) | (p[2] >> 4)) & 31;				note->command = p[2] & 0x0F;				note->param = p[3];			} 			if (numChannels < PAULA_VOICES)				note += PAULA_VOICES-numChannels;		}	} 	if (modFormat != FORMAT_PT) // pattern command conversion for non-PT formats	{		for (int32_t i = 0; i < numPatterns; i++)		{			note_t *note = m->patterns[i];			for (int32_t j = 0; j < MOD_ROWS*4; j++, note++)			{				if (modFormat == FORMAT_NT || modFormat == FORMAT_HMNT)				{					// any Dxx == D00 in NT/HMNT					if (note->command == 0xD)						note->param = 0; 					// effect F with param 0x00 does nothing in NT/HMNT					if (note->command == 0xF && note->param == 0)						note->command = 0;				}				else if (modFormat == FORMAT_FLT) // Startrekker (4 channels)				{					if (note->command == 0xE) // remove unsupported "assembly macros" command					{						note->command = 0;						note->param = 0;					} 					// Startrekker is always in vblank mode, and limits speed to 0x1F					if (note->command == 0xF && note->param > 0x1F)						note->param = 0x1F;				} 				// remove E8x (Karplus-Strong is only supported for ProTracker .MODs)				if (note->command == 0xE && (note->param >> 4) == 0x8)				{					note->command = 0;					note->param = 0;				} 				// remove EFx (Invert Loop is only supported for ProTracker .MODs)				if (note->command == 0xE && (note->param >> 4) == 0xF)				{					note->command = 0;					note->param = 0;				}			}		}	} 	// load sample data	s = m->samples;	for (int32_t i = 0; i < MOD_SAMPLES; i++, s++)	{		int32_t bytesToSkip = 0;		if (realSampleLengths[i] > config.maxSampleLength)			bytesToSkip = realSampleLengths[i] - config.maxSampleLength; 		memcpy(&m->sampleData[s->offset], p, s->length); p += s->length;		if (bytesToSkip > 0)			p += bytesToSkip;	} 	m->header.initialTempo = 125;	return m; loadError:	if (m != NULL)	{		for (int32_t i = 0; i < MAX_PATTERNS; i++)		{			if (m->patterns[i] != NULL)				free(m->patterns[i]);		} 		if (m->sampleData != NULL)			free(m->sampleData); 		free(m);	} 	return NULL;} static uint8_t getMod31Type(uint8_t *buffer, uint32_t filesize, uint8_t *numChannels) // 0 = not detected{	const uint8_t *id = &buffer[1080];#define ID(s) !memcmp(s, id, 4) 	*numChannels = 0;	if (buffer == NULL || filesize < 1084+1024)		return FORMAT_UNKNOWN; 	*numChannels = 4;	if (ID("M.K.") || ID("M!K!") || ID("NSMS") || ID("LARD") || ID("PATT"))	{		return FORMAT_PT; // ProTracker (or compatible)	}	else if (ID("FLT4"))	{		return FORMAT_FLT; // Startrekker (4 channels)	}	else if (ID("N.T."))	{		return FORMAT_NT; // NoiseTracker	}	else if (ID("M&K!") || ID("FEST"))	{		return FORMAT_HMNT; // His Master's NoiseTracker	}	else if (isdigit(id[0]) && (id[1] == 'C' && id[2] == 'H' && id[3] == 'N'))	{		*numChannels = id[0] - '0';		return FORMAT_FT2; // Fasttracker II 1..9 channels (or other trackers)	}	else if (isdigit(id[0]) && isdigit(id[1]) && id[1] == 'C' && id[2] == 'H')	{		*numChannels = ((id[0] - '0') * 10) + (id[1] - '0');		return FORMAT_FT2; // Fasttracker II 10+ channels (or other trackers)	} 	return FORMAT_UNKNOWN;} bool detectMod31(uint8_t *buffer, uint32_t filesize){	uint8_t junk; 	if (buffer == NULL || filesize < 1084+1024)		return FORMAT_UNKNOWN; 	return getMod31Type(buffer, filesize, &junk) != FORMAT_UNKNOWN;}