From 20a8edc67a286a5649e76c06b47dd57856aa8fa5 Mon Sep 17 00:00:00 2001
From: Lauchmelder <robert.altner11@gmail.com>
Date: Sun, 17 Apr 2022 20:18:20 +0200
Subject: [PATCH] added instrument mapping

---
 src/main.c    | 32 +++++++++++++++++++-------
 src/mapping.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/mapping.h |  9 ++++++++
 src/message.c |  2 +-
 4 files changed, 97 insertions(+), 9 deletions(-)
 create mode 100644 src/mapping.c
 create mode 100644 src/mapping.h

diff --git a/src/main.c b/src/main.c
index 52e3995..324e48f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -8,14 +8,16 @@
 
 #include "midi_interface.h"
 #include "midi_parser.h"
+#include "mapping.h"
 
 typedef struct 
 {
-    const char* midi_file;
-    const char* mapping_file;
+    char* midi_file;
+    char* mapping_file;
 } CommandArguments;
 
 MidiInterface* interface;
+uint8_t* map;
 
 static int _Atomic playing = ATOMIC_VAR_INIT(0);
 static uint32_t _Atomic time_per_quarter = ATOMIC_VAR_INIT(1);
@@ -30,9 +32,14 @@ int main(int argc, char** argv)
 {
     CommandArguments args = parse_command_args(argc, argv);
 
+    if(args.mapping_file)
+        map = load_program_map(args.mapping_file);
+    else
+        map = get_default_map();
+
     printf("Loading MIDI file...\n");
     MidiParser* parser;
-    parser = parseMidi(argv[1], false, true);
+    parser = parseMidi(args.midi_file, false, true);
     if(!parser)
     {
         fprintf(stderr, "Failed to read MIDI file\n");
@@ -63,7 +70,8 @@ int main(int argc, char** argv)
     }
     free(threads);
     close_midi_device(interface);
-    
+    free(map);
+
     return 0;
 }
 
@@ -133,12 +141,15 @@ void* play_track(void* data)
 
                 case MidiProgramChanged:
                     message->type = PROGRAM_CHANGE;
+                    // printf("ch %u mapped %u to %u\n", message->channel, message->data[0], map[message->data[0]]);
+                    message->data[0] = map[message->data[0]];
                     break;
 
                 default:
                     break;
             }
-            // printf("Sending %d %d\n", message->data[0], message->data[1]);
+
+            // printf("ch %u\n", message->channel);
             int result = write_midi_device(interface, message);
             if(result < 0)
                 fprintf(stderr, "Write err: %s\n", midi_strerror(result));
@@ -166,21 +177,26 @@ CommandArguments parse_command_args(int argc, char** argv)
         case 'm':
         {
             size_t len = strlen(optarg);
-            parsed_args.mapping_file = (const char*)malloc(len);
+            parsed_args.mapping_file = (char*)malloc(len);
             memcpy((void*)parsed_args.mapping_file, (void*)optarg, len);
         } break;
 
         case 'h':
             fprintf(stderr, "Usage: %s [-m mapping_file] midi_file\n", argv[0]);
             exit(EXIT_SUCCESS);
+
+        default:
+            exit(EXIT_FAILURE);
+            break;
         }
+
     }
 
     if(optind < argc)
     {
         size_t len = strlen(argv[optind]);
-        parsed_args.midi_file = (const char*)malloc(len);
-        memcpy((void*)parsed_args.midi_file, (void*)argv[optind], len);
+        parsed_args.midi_file = (char*)malloc(len + 1);
+        strcpy(parsed_args.midi_file, argv[optind]);
     }
 
     if(parsed_args.midi_file == NULL)
diff --git a/src/mapping.c b/src/mapping.c
new file mode 100644
index 0000000..a51376f
--- /dev/null
+++ b/src/mapping.c
@@ -0,0 +1,63 @@
+#include "mapping.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+uint8_t* load_program_map(const char* filename)
+{
+    FILE* fp = fopen(filename, "r");
+    if(fp == NULL)
+    {
+        fprintf(stderr, "Failed to open mapping file %s\n", filename);
+        exit(EXIT_FAILURE);
+    }
+
+    uint8_t* map = (uint8_t*)calloc(1, 127);
+
+    size_t read;
+    size_t current_line = 0;
+    size_t len = 0;
+    char* line = NULL;
+    while((read = getline(&line, &len, fp)) != -1)
+    {
+        current_line++;
+        if(read == 1)
+            continue;
+
+        size_t colon_pos = 0;
+        do
+        {
+            if(line[colon_pos] == '\0')
+            {
+                fprintf(stderr, "Invalid syntax in mapping file at line %u. Ignoring.\n", current_line);
+                continue;
+            }
+        } while(line[++colon_pos] != ':');
+  
+        line[colon_pos] = '\0';
+        int from = atoi(line);
+        int to = atoi(line + colon_pos + 1);
+
+        if(from < 0 || 127 < from)
+        {
+            fprintf(stderr, "Invalid MIDI program ID in line %u. Ignoring\n", current_line);
+            continue;
+        }
+
+        map[from & 0xFF] = to & 0xFF;
+    }
+
+    fclose(fp);
+    return map;
+}
+
+uint8_t* get_default_map()
+{
+    uint8_t* map = (uint8_t*)malloc(127);
+    for(int i = 1; i < 128; i++)
+    {
+        map[i] = i;
+    }
+
+    return map;
+}
\ No newline at end of file
diff --git a/src/mapping.h b/src/mapping.h
new file mode 100644
index 0000000..334c9b7
--- /dev/null
+++ b/src/mapping.h
@@ -0,0 +1,9 @@
+#ifndef _MAPPING_H_
+#define _MAPPING_H_
+
+#include <stdint.h>
+
+uint8_t* load_program_map(const char* filename);
+uint8_t* get_default_map();
+
+#endif
\ No newline at end of file
diff --git a/src/message.c b/src/message.c
index e91e0ac..e101e7d 100644
--- a/src/message.c
+++ b/src/message.c
@@ -94,6 +94,6 @@ int encode_status_byte(const Message* message, uint8_t* status)
     default:
         return MIDI_UNKNOWN_STATUS_BYTE;
     }
-
+    
     return 0;   
 }
\ No newline at end of file