/* * Adplug - Replayer for many OPL2/OPL3 audio file formats. * Copyright (C) 1999 - 2003 Simon Peter, , et al. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * bam.cpp - Bob's Adlib Music Player, by Simon Peter * * NOTES: * In my player, the loop counter is stored with the label. This can be * dangerous for some situations (see below), but there shouldn't be any BAM * files triggering this situation. * * From SourceForge Bug #476088: * ----------------------------- * Using just one loop counter for each label, my player can't * handle files that loop twice to the same label (if that's at * all possible with BAM). Imagine the following situation: * * ... [*] ---- [<- *] ---- [<- *] ... * ^ ^ ^ ^ ^ ^ ^ * | | | | | | | * +---|----+-----|-----+-----|----+--- normal song data * +----------|-----------|-------- label 1 * +-----------+-------- loop points to label 1 * * both loop points loop to the same label. Storing the loop * count with the label would cause chaos with the counter, * when the player executes the inner jump. * ------------------ * Not to worry. my reference implementation of BAM does not * support the multiple loop situation you describe, and * neither do any BAM-creation programs. Then both loops point * to the same label, the inner loop's counter is just allowed * to clobber the outer loop's counter. No stack is neccisary. */ #include #include "bam.h" const unsigned short CbamPlayer::freq[] = {172,182,193,205,217,230,243,258,274, 290,307,326,345,365,387,410,435,460,489,517,547,580,614,651,1369,1389,1411, 1434,1459,1484,1513,1541,1571,1604,1638,1675,2393,2413,2435,2458,2483,2508, 2537,2565,2595,2628,2662,2699,3417,3437,3459,3482,3507,3532,3561,3589,3619, 3652,3686,3723,4441,4461,4483,4506,4531,4556,4585,4613,4643,4676,4710,4747, 5465,5485,5507,5530,5555,5580,5609,5637,5667,5700,5734,5771,6489,6509,6531, 6554,6579,6604,6633,6661,6691,6724,6758,6795,7513,7533,7555,7578,7603,7628, 7657,7685,7715,7748,7782,7819,7858,7898,7942,7988,8037,8089,8143,8191,8191, 8191,8191,8191,8191,8191,8191,8191,8191,8191,8191}; CPlayer *CbamPlayer::factory(Copl *newopl) { return new CbamPlayer(newopl); } bool CbamPlayer::load(const char *filename, const CFileProvider &fp) { binistream *f = fp.open(filename); if(!f) return false; char id[4]; unsigned int i; size = fp.filesize(f) - 4; // filesize minus header f->readString(id, 4); if(strncmp(id,"CBMF",4)) { fp.close(f); return false; } song = new unsigned char [size]; for(i = 0; i < size; i++) song[i] = f->readInt(1); fp.close(f); rewind(0); return true; } bool CbamPlayer::update() { unsigned char cmd,c; if(del) { del--; return !songend; } if(pos >= size) { // EOF detection pos = 0; songend = true; } while(song[pos] < 128) { cmd = song[pos] & 240; c = song[pos] & 15; switch(cmd) { case 0: // stop song pos = 0; songend = true; break; case 16: // start note if(c < 9) { opl->write(0xa0 + c, freq[song[++pos]] & 255); opl->write(0xb0 + c, (freq[song[pos]] >> 8) + 32); } else pos++; pos++; break; case 32: // stop note if(c < 9) opl->write(0xb0 + c, 0); pos++; break; case 48: // define instrument if(c < 9) { opl->write(0x20 + op_table[c],song[pos+1]); opl->write(0x23 + op_table[c],song[pos+2]); opl->write(0x40 + op_table[c],song[pos+3]); opl->write(0x43 + op_table[c],song[pos+4]); opl->write(0x60 + op_table[c],song[pos+5]); opl->write(0x63 + op_table[c],song[pos+6]); opl->write(0x80 + op_table[c],song[pos+7]); opl->write(0x83 + op_table[c],song[pos+8]); opl->write(0xe0 + op_table[c],song[pos+9]); opl->write(0xe3 + op_table[c],song[pos+10]); opl->write(0xc0 + c,song[pos+11]); } pos += 12; break; case 80: // set label label[c].target = ++pos; label[c].defined = true; break; case 96: // jump if(label[c].defined) switch(song[pos+1]) { case 254: // infinite loop if(label[c].defined) { pos = label[c].target; songend = true; break; } // fall through... case 255: // chorus if(!chorus && label[c].defined) { chorus = true; gosub = pos + 2; pos = label[c].target; break; } // fall through... case 0: // end of loop pos += 2; break; default: // finite loop if(!label[c].count) { // loop elapsed label[c].count = 255; pos += 2; break; } if(label[c].count < 255) // loop defined label[c].count--; else // loop undefined label[c].count = song[pos+1] - 1; pos = label[c].target; break; } break; case 112: // end of chorus if(chorus) { pos = gosub; chorus = false; } else pos++; break; default: // reserved command (skip) pos++; break; } } if(song[pos] >= 128) { // wait del = song[pos] - 127; pos++; } return !songend; } void CbamPlayer::rewind(int subsong) { int i; pos = 0; songend = false; del = 0; gosub = 0; chorus = false; memset(label, 0, sizeof(label)); label[0].defined = true; for(i = 0; i < 16; i++) label[i].count = 255; // 255 = undefined opl->init(); opl->write(1,32); }