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Diffstat (limited to 'src/midifile.c')
| -rw-r--r-- | src/midifile.c | 815 |
1 files changed, 815 insertions, 0 deletions
diff --git a/src/midifile.c b/src/midifile.c new file mode 100644 index 00000000..bd935ca1 --- /dev/null +++ b/src/midifile.c @@ -0,0 +1,815 @@ +// Emacs style mode select -*- C++ -*- +//----------------------------------------------------------------------------- +// +// Copyright(C) 2009 Simon Howard +// +// 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., 59 Temple Place - Suite 330, Boston, MA +// 02111-1307, USA. +// +// DESCRIPTION: +// Reading of MIDI files. +// +//----------------------------------------------------------------------------- + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> + +#include "doomdef.h" +#include "doomtype.h" +#include "i_swap.h" +#include "midifile.h" + +#define HEADER_CHUNK_ID "MThd" +#define TRACK_CHUNK_ID "MTrk" +#define MAX_BUFFER_SIZE 0x10000 + +typedef struct +{ + byte chunk_id[4]; + unsigned int chunk_size; +} PACKEDATTR chunk_header_t; + +typedef struct +{ + chunk_header_t chunk_header; + unsigned short format_type; + unsigned short num_tracks; + unsigned short time_division; +} PACKEDATTR midi_header_t; + +typedef struct +{ + // Length in bytes: + + unsigned int data_len; + + // Events in this track: + + midi_event_t *events; + int num_events; +} midi_track_t; + +struct midi_track_iter_s +{ + midi_track_t *track; + unsigned int position; +}; + +struct midi_file_s +{ + midi_header_t header; + + // All tracks in this file: + midi_track_t *tracks; + unsigned int num_tracks; + + // Data buffer used to store data read for SysEx or meta events: + byte *buffer; + unsigned int buffer_size; +}; + +// Check the header of a chunk: + +static boolean CheckChunkHeader(chunk_header_t *chunk, + char *expected_id) +{ + boolean result; + + result = (memcmp((char *) chunk->chunk_id, expected_id, 4) == 0); + + if (!result) + { + fprintf(stderr, "CheckChunkHeader: Expected '%s' chunk header, " + "got '%c%c%c%c'\n", + expected_id, + chunk->chunk_id[0], chunk->chunk_id[1], + chunk->chunk_id[2], chunk->chunk_id[3]); + } + + return result; +} + +// Read a single byte. Returns false on error. + +static boolean ReadByte(byte *result, FILE *stream) +{ + int c; + + c = fgetc(stream); + + if (c == EOF) + { + fprintf(stderr, "ReadByte: Unexpected end of file\n"); + return false; + } + else + { + *result = (byte) c; + + return true; + } +} + +// Read a variable-length value. + +static boolean ReadVariableLength(unsigned int *result, FILE *stream) +{ + int i; + byte b; + + *result = 0; + + for (i=0; i<4; ++i) + { + if (!ReadByte(&b, stream)) + { + fprintf(stderr, "ReadVariableLength: Error while reading " + "variable-length value\n"); + return false; + } + + // Insert the bottom seven bits from this byte. + + *result <<= 7; + *result |= b & 0x7f; + + // If the top bit is not set, this is the end. + + if ((b & 0x80) == 0) + { + return true; + } + } + + fprintf(stderr, "ReadVariableLength: Variable-length value too " + "long: maximum of four bytes\n"); + return false; +} + +// Read a byte sequence into the data buffer. + +static void *ReadByteSequence(unsigned int num_bytes, FILE *stream) +{ + unsigned int i; + byte *result; + + // Allocate a buffer: + + result = malloc(num_bytes); + + if (result == NULL) + { + fprintf(stderr, "ReadByteSequence: Failed to allocate buffer\n"); + return NULL; + } + + // Read the data: + + for (i=0; i<num_bytes; ++i) + { + if (!ReadByte(&result[i], stream)) + { + fprintf(stderr, "ReadByteSequence: Error while reading byte %u\n", + i); + free(result); + return NULL; + } + } + + return result; +} + +// Read a MIDI channel event. +// two_param indicates that the event type takes two parameters +// (three byte) otherwise it is single parameter (two byte) + +static boolean ReadChannelEvent(midi_event_t *event, + byte event_type, boolean two_param, + FILE *stream) +{ + byte b; + + // Set basics: + + event->event_type = event_type & 0xf0; + event->data.channel.channel = event_type & 0x0f; + + // Read parameters: + + if (!ReadByte(&b, stream)) + { + fprintf(stderr, "ReadChannelEvent: Error while reading channel " + "event parameters\n"); + return false; + } + + event->data.channel.param1 = b; + + // Second parameter: + + if (two_param) + { + if (!ReadByte(&b, stream)) + { + fprintf(stderr, "ReadChannelEvent: Error while reading channel " + "event parameters\n"); + return false; + } + + event->data.channel.param2 = b; + } + + return true; +} + +// Read sysex event: + +static boolean ReadSysExEvent(midi_event_t *event, int event_type, + FILE *stream) +{ + event->event_type = event_type; + + if (!ReadVariableLength(&event->data.sysex.length, stream)) + { + fprintf(stderr, "ReadSysExEvent: Failed to read length of " + "SysEx block\n"); + return false; + } + + // Read the byte sequence: + + event->data.sysex.data = ReadByteSequence(event->data.sysex.length, stream); + + if (event->data.sysex.data == NULL) + { + fprintf(stderr, "ReadSysExEvent: Failed while reading SysEx event\n"); + return false; + } + + return true; +} + +// Read meta event: + +static boolean ReadMetaEvent(midi_event_t *event, FILE *stream) +{ + byte b; + + event->event_type = MIDI_EVENT_META; + + // Read meta event type: + + if (!ReadByte(&b, stream)) + { + fprintf(stderr, "ReadMetaEvent: Failed to read meta event type\n"); + return false; + } + + event->data.meta.type = b; + + // Read length of meta event data: + + if (!ReadVariableLength(&event->data.meta.length, stream)) + { + fprintf(stderr, "ReadSysExEvent: Failed to read length of " + "SysEx block\n"); + return false; + } + + // Read the byte sequence: + + event->data.meta.data = ReadByteSequence(event->data.meta.length, stream); + + if (event->data.meta.data == NULL) + { + fprintf(stderr, "ReadSysExEvent: Failed while reading SysEx event\n"); + return false; + } + + return true; +} + +static boolean ReadEvent(midi_event_t *event, unsigned int *last_event_type, + FILE *stream) +{ + byte event_type; + + if (!ReadVariableLength(&event->delta_time, stream)) + { + fprintf(stderr, "ReadEvent: Failed to read event timestamp\n"); + return false; + } + + if (!ReadByte(&event_type, stream)) + { + fprintf(stderr, "ReadEvent: Failed to read event type\n"); + return false; + } + + // All event types have their top bit set. Therefore, if + // the top bit is not set, it is because we are using the "same + // as previous event type" shortcut to save a byte. Skip back + // a byte so that we read this byte again. + + if ((event_type & 0x80) == 0) + { + event_type = *last_event_type; + + if (fseek(stream, -1, SEEK_CUR) < 0) + { + fprintf(stderr, "ReadEvent: Unable to seek in stream\n"); + return false; + } + } + else + { + *last_event_type = event_type; + } + + // Check event type: + + switch (event_type & 0xf0) + { + // Two parameter channel events: + + case MIDI_EVENT_NOTE_OFF: + case MIDI_EVENT_NOTE_ON: + case MIDI_EVENT_AFTERTOUCH: + case MIDI_EVENT_CONTROLLER: + case MIDI_EVENT_PITCH_BEND: + return ReadChannelEvent(event, event_type, true, stream); + + // Single parameter channel events: + + case MIDI_EVENT_PROGRAM_CHANGE: + case MIDI_EVENT_CHAN_AFTERTOUCH: + return ReadChannelEvent(event, event_type, false, stream); + + default: + break; + } + + // Specific value? + + switch (event_type) + { + case MIDI_EVENT_SYSEX: + case MIDI_EVENT_SYSEX_SPLIT: + return ReadSysExEvent(event, event_type, stream); + + case MIDI_EVENT_META: + return ReadMetaEvent(event, stream); + + default: + break; + } + + fprintf(stderr, "ReadEvent: Unknown MIDI event type: 0x%x\n", event_type); + return false; +} + +// Free an event: + +static void FreeEvent(midi_event_t *event) +{ + // Some event types have dynamically allocated buffers assigned + // to them that must be freed. + + switch (event->event_type) + { + case MIDI_EVENT_SYSEX: + case MIDI_EVENT_SYSEX_SPLIT: + free(event->data.sysex.data); + break; + + case MIDI_EVENT_META: + free(event->data.meta.data); + break; + + default: + // Nothing to do. + break; + } +} + +// Read and check the track chunk header + +static boolean ReadTrackHeader(midi_track_t *track, FILE *stream) +{ + size_t records_read; + chunk_header_t chunk_header; + + records_read = fread(&chunk_header, sizeof(chunk_header_t), 1, stream); + + if (records_read < 1) + { + return false; + } + + if (!CheckChunkHeader(&chunk_header, TRACK_CHUNK_ID)) + { + return false; + } + + track->data_len = SDL_SwapBE32(chunk_header.chunk_size); + + return true; +} + +static boolean ReadTrack(midi_track_t *track, FILE *stream) +{ + midi_event_t *new_events; + midi_event_t *event; + unsigned int last_event_type; + + track->num_events = 0; + track->events = NULL; + + // Read the header: + + if (!ReadTrackHeader(track, stream)) + { + return false; + } + + // Then the events: + + last_event_type = 0; + + for (;;) + { + // Resize the track slightly larger to hold another event: + + new_events = realloc(track->events, + sizeof(midi_event_t) * (track->num_events + 1)); + + if (new_events == NULL) + { + return false; + } + + track->events = new_events; + + // Read the next event: + + event = &track->events[track->num_events]; + if (!ReadEvent(event, &last_event_type, stream)) + { + return false; + } + + ++track->num_events; + + // End of track? + + if (event->event_type == MIDI_EVENT_META + && event->data.meta.type == MIDI_META_END_OF_TRACK) + { + break; + } + } + + return true; +} + +// Free a track: + +static void FreeTrack(midi_track_t *track) +{ + unsigned int i; + + for (i=0; i<track->num_events; ++i) + { + FreeEvent(&track->events[i]); + } + + free(track->events); +} + +static boolean ReadAllTracks(midi_file_t *file, FILE *stream) +{ + unsigned int i; + + // Allocate list of tracks and read each track: + + file->tracks = malloc(sizeof(midi_track_t) * file->num_tracks); + + if (file->tracks == NULL) + { + return false; + } + + memset(file->tracks, 0, sizeof(midi_track_t) * file->num_tracks); + + // Read each track: + + for (i=0; i<file->num_tracks; ++i) + { + if (!ReadTrack(&file->tracks[i], stream)) + { + return false; + } + } + + return true; +} + +// Read and check the header chunk. + +static boolean ReadFileHeader(midi_file_t *file, FILE *stream) +{ + size_t records_read; + unsigned int format_type; + + records_read = fread(&file->header, sizeof(midi_header_t), 1, stream); + + if (records_read < 1) + { + return false; + } + + if (!CheckChunkHeader(&file->header.chunk_header, HEADER_CHUNK_ID) + || SDL_SwapBE32(file->header.chunk_header.chunk_size) != 6) + { + fprintf(stderr, "ReadFileHeader: Invalid MIDI chunk header! " + "chunk_size=%i\n", + SDL_SwapBE32(file->header.chunk_header.chunk_size)); + return false; + } + + format_type = SDL_SwapBE16(file->header.format_type); + file->num_tracks = SDL_SwapBE16(file->header.num_tracks); + + if ((format_type != 0 && format_type != 1) + || file->num_tracks < 1) + { + fprintf(stderr, "ReadFileHeader: Only type 0/1 " + "MIDI files supported!\n"); + return false; + } + + return true; +} + +void MIDI_FreeFile(midi_file_t *file) +{ + int i; + + if (file->tracks != NULL) + { + for (i=0; i<file->num_tracks; ++i) + { + FreeTrack(&file->tracks[i]); + } + + free(file->tracks); + } + + free(file); +} + +midi_file_t *MIDI_LoadFile(char *filename) +{ + midi_file_t *file; + FILE *stream; + + file = malloc(sizeof(midi_file_t)); + + if (file == NULL) + { + return NULL; + } + + file->tracks = NULL; + file->num_tracks = 0; + file->buffer = NULL; + file->buffer_size = 0; + + // Open file + + stream = fopen(filename, "rb"); + + if (stream == NULL) + { + fprintf(stderr, "MIDI_LoadFile: Failed to open '%s'\n", filename); + MIDI_FreeFile(file); + return NULL; + } + + // Read MIDI file header + + if (!ReadFileHeader(file, stream)) + { + fclose(stream); + MIDI_FreeFile(file); + return NULL; + } + + // Read all tracks: + + if (!ReadAllTracks(file, stream)) + { + fclose(stream); + MIDI_FreeFile(file); + return NULL; + } + + fclose(stream); + + return file; +} + +// Get the number of tracks in a MIDI file. + +unsigned int MIDI_NumTracks(midi_file_t *file) +{ + return file->num_tracks; +} + +// Start iterating over the events in a track. + +midi_track_iter_t *MIDI_IterateTrack(midi_file_t *file, unsigned int track) +{ + midi_track_iter_t *iter; + + assert(track < file->num_tracks); + + iter = malloc(sizeof(*iter)); + iter->track = &file->tracks[track]; + iter->position = 0; + + return iter; +} + +void MIDI_FreeIterator(midi_track_iter_t *iter) +{ + free(iter); +} + +// Get the time until the next MIDI event in a track. + +unsigned int MIDI_GetDeltaTime(midi_track_iter_t *iter) +{ + if (iter->position < iter->track->num_events) + { + midi_event_t *next_event; + + next_event = &iter->track->events[iter->position]; + + return next_event->delta_time; + } + else + { + return 0; + } +} + +// Get a pointer to the next MIDI event. + +int MIDI_GetNextEvent(midi_track_iter_t *iter, midi_event_t **event) +{ + if (iter->position < iter->track->num_events) + { + *event = &iter->track->events[iter->position]; + ++iter->position; + + return 1; + } + else + { + return 0; + } +} + +unsigned int MIDI_GetFileTimeDivision(midi_file_t *file) +{ + return file->header.time_division; +} + +void MIDI_RestartIterator(midi_track_iter_t *iter) +{ + iter->position = 0; +} + +#ifdef TEST + +static char *MIDI_EventTypeToString(midi_event_type_t event_type) +{ + switch (event_type) + { + case MIDI_EVENT_NOTE_OFF: + return "MIDI_EVENT_NOTE_OFF"; + case MIDI_EVENT_NOTE_ON: + return "MIDI_EVENT_NOTE_ON"; + case MIDI_EVENT_AFTERTOUCH: + return "MIDI_EVENT_AFTERTOUCH"; + case MIDI_EVENT_CONTROLLER: + return "MIDI_EVENT_CONTROLLER"; + case MIDI_EVENT_PROGRAM_CHANGE: + return "MIDI_EVENT_PROGRAM_CHANGE"; + case MIDI_EVENT_CHAN_AFTERTOUCH: + return "MIDI_EVENT_CHAN_AFTERTOUCH"; + case MIDI_EVENT_PITCH_BEND: + return "MIDI_EVENT_PITCH_BEND"; + case MIDI_EVENT_SYSEX: + return "MIDI_EVENT_SYSEX"; + case MIDI_EVENT_SYSEX_SPLIT: + return "MIDI_EVENT_SYSEX_SPLIT"; + case MIDI_EVENT_META: + return "MIDI_EVENT_META"; + + default: + return "(unknown)"; + } +} + +void PrintTrack(midi_track_t *track) +{ + midi_event_t *event; + unsigned int i; + + for (i=0; i<track->num_events; ++i) + { + event = &track->events[i]; + + if (event->delta_time > 0) + { + printf("Delay: %i ticks\n", event->delta_time); + } + + printf("Event type: %s (%i)\n", + MIDI_EventTypeToString(event->event_type), + event->event_type); + + switch(event->event_type) + { + case MIDI_EVENT_NOTE_OFF: + case MIDI_EVENT_NOTE_ON: + case MIDI_EVENT_AFTERTOUCH: + case MIDI_EVENT_CONTROLLER: + case MIDI_EVENT_PROGRAM_CHANGE: + case MIDI_EVENT_CHAN_AFTERTOUCH: + case MIDI_EVENT_PITCH_BEND: + printf("\tChannel: %i\n", event->data.channel.channel); + printf("\tParameter 1: %i\n", event->data.channel.param1); + printf("\tParameter 2: %i\n", event->data.channel.param2); + break; + + case MIDI_EVENT_SYSEX: + case MIDI_EVENT_SYSEX_SPLIT: + printf("\tLength: %i\n", event->data.sysex.length); + break; + + case MIDI_EVENT_META: + printf("\tMeta type: %i\n", event->data.meta.type); + printf("\tLength: %i\n", event->data.meta.length); + break; + } + } +} + +int main(int argc, char *argv[]) +{ + midi_file_t *file; + unsigned int i; + + if (argc < 2) + { + printf("Usage: %s <filename>\n", argv[0]); + exit(1); + } + + file = MIDI_LoadFile(argv[1]); + + if (file == NULL) + { + fprintf(stderr, "Failed to open %s\n", argv[1]); + exit(1); + } + + for (i=0; i<file->num_tracks; ++i) + { + printf("\n== Track %i ==\n\n", i); + + PrintTrack(&file->tracks[i]); + } + + return 0; +} + +#endif + |