Wav file loading

2 files changed, 98 insertions, 0 deletions

diff --git a/src/wav.c b/src/wav.c
new file mode 100644
index 0000000..61765d6
--- /dev/null
+++ b/src/wav.c
@@ -0,0 +1,52 @@
+#include "wav.h"
+#include "smrt_arena.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+void seek_to_chunk(FILE *file, char *chunk_name) {
+    char cur_name[4];
+     u32  chunk_size;
+
+    fseek(file, sizeof(wav_master_chunk_t), SEEK_SET);
+    while (true) {
+        fread(cur_name, 4, 1, file);
+        fread(&chunk_size, 4, 1, file);
+
+        if (strcmp(cur_name, chunk_name) == 0) {
+            break;
+        }
+
+        fseek(file, chunk_size, SEEK_CUR);
+    }
+
+    fseek(file, -8, SEEK_CUR);
+}
+
+wav_data_t *load_wav_file(smrt_arena_t *arena, char *filename, wav_master_chunk_t *master_o, wav_fmt_chunk_t *format_o) {
+    FILE *wav_file = fopen(filename, "rb");
+
+    if (!wav_file) {
+        return NULL;
+    }
+
+    fread(master_o, sizeof(wav_master_chunk_t), 1, wav_file);
+
+    seek_to_chunk(wav_file, "fmt ");
+    fread(format_o, sizeof(wav_fmt_chunk_t), 1, wav_file);
+
+    seek_to_chunk(wav_file, "data");
+    fseek(wav_file, 4, SEEK_CUR);
+    u32 sampled_data_size;
+    fread(&sampled_data_size, 4, 1, wav_file);
+
+    wav_data_t *data = smrt_arena_push(arena, sizeof(wav_data_t) + sampled_data_size, true);
+    fread((u8*)data+WAV_DATA_BASE_POS, sampled_data_size, 1, wav_file);
+    data->sample_count = sampled_data_size / ((format_o->bits_per_sample / 8) * format_o->num_channels);
+
+    return data;
+}
+
+void write_wav_file(char *filename, wav_fmt_chunk_t *header_i, wav_data_t *data_i);
+wav_fmt_chunk_t make_wav_fmt_chunk(u32 num_channels, u32 sample_rate, u16 bits_per_sample, wav_data_t *data_i);
diff --git a/src/wav.h b/src/wav.h
new file mode 100644
index 0000000..dd85ccd
--- /dev/null
+++ b/src/wav.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include "common.h"
+#include "smrt_arena.h"
+
+#define WAV_DATA_BASE_POS sizeof(wav_data_t)
+
+typedef struct {
+    u64    sample_count;
+} wav_data_t;
+
+// [Master RIFF chunk]
+//     FileTypeBlocID  (4 bytes) : Identifier « RIFF »  (0x52, 0x49, 0x46, 0x46)
+//     FileSize        (4 bytes) : Overall file size minus 8 bytes
+//     FileFormatID    (4 bytes) : Format = « WAVE »  (0x57, 0x41, 0x56, 0x45)
+#pragma pack(push, 1)
+typedef struct {
+     u8        chunk_id[4];
+    u32          file_size;
+     u8  file_format_id[4];
+} wav_master_chunk_t;
+
+// [Chunk describing the data format]
+//     FormatBlocID    (4 bytes) : Identifier « fmt␣ »  (0x66, 0x6D, 0x74, 0x20)
+//     BlocSize        (4 bytes) : Chunk size minus 8 bytes
+//     AudioFormat     (2 bytes) : Audio format (1: PCM integer, 3: IEEE 754 float)
+//     NbrChannels     (2 bytes) : Number of channels
+//     Frequency       (4 bytes) : Sample rate (in hertz)
+//     BytePerSec      (4 bytes) : Number of bytes to read per second (Frequency * BytePerBloc).
+//     BytePerBloc     (2 bytes) : Number of bytes per block (NbrChannels * BitsPerSample / 8).
+//     BitsPerSample   (2 bytes) : Number of bits per sample
+typedef struct {
+     u8     chunk_id[4];
+    u32      chunk_size;
+    u16    audio_format;
+    u16    num_channels;
+    u32     sample_rate;
+    u32   byter_per_sec;
+    u16 bytes_per_block;
+    u16 bits_per_sample;
+} wav_fmt_chunk_t;
+#pragma pack(pop)
+
+     wav_data_t     *load_wav_file(smrt_arena_t *arena, char *filename, wav_master_chunk_t *master_o, wav_fmt_chunk_t *format_o);
+           void     write_wav_file(char *filename, wav_fmt_chunk_t *header_i, wav_data_t *data_i);
+wav_fmt_chunk_t make_wav_fmt_chunk(u32 num_channels, u32 sample_rate, u16 bits_per_sample, wav_data_t *data_i);