Wav funcs and tests

1 files changed, 57 insertions, 15 deletions

diff --git a/src/wav.c b/src/wav.c
index 61765d6..665998d 100644
--- a/src/wav.c
+++ b/src/wav.c
@@ -5,48 +5,90 @@
 #include <stdio.h>
 #include <string.h>
 
-void seek_to_chunk(FILE *file, char *chunk_name) {
+b32 seek_to_chunk(FILE *file, char const *chunk_name) {
     char cur_name[4];
      u32  chunk_size;
 
+    fseek(file, 0, SEEK_END);
+    const i64 max_pos = ftell(file);
     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;
-        }
+        if (memcmp(cur_name, chunk_name, 4) == 0) break;
+
+        if (chunk_size % 2 == 1) chunk_size++;
+
+        if (ftell(file) + (i64)chunk_size >= max_pos) return false;
 
         fseek(file, chunk_size, SEEK_CUR);
     }
 
     fseek(file, -8, SEEK_CUR);
+    return true;
 }
 
-wav_data_t *load_wav_file(smrt_arena_t *arena, char *filename, wav_master_chunk_t *master_o, wav_fmt_chunk_t *format_o) {
+wav_data_t load_wav_file(smrt_arena_t *arena, char *filename, wav_master_chunk_t *master_o, wav_fmt_chunk_t *format_o) {
+    wav_data_t data = { 0 };
+
     FILE *wav_file = fopen(filename, "rb");
 
-    if (!wav_file) {
-        return NULL;
-    }
+    if (!wav_file) return data;
 
     fread(master_o, sizeof(wav_master_chunk_t), 1, wav_file);
 
-    seek_to_chunk(wav_file, "fmt ");
+    if (seek_to_chunk(wav_file, "fmt ") == false) return data;
     fread(format_o, sizeof(wav_fmt_chunk_t), 1, wav_file);
 
-    seek_to_chunk(wav_file, "data");
+    if (seek_to_chunk(wav_file, "data") == false) return 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);
+    data.samples = smrt_arena_push(arena, sizeof(wav_data_t) + sampled_data_size, true);
+    if (!data.samples) return data;
+
+    fread((u8*)data.samples+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);
+b32 write_wav_file(char *filename, wav_fmt_chunk_t *fmt_chunk_i, wav_data_t data_i) {
+    FILE *wav_file = fopen(filename, "wb");
+
+    if (!wav_file) return false;
+
+    u64 data_size_bytes = data_i.sample_count * fmt_chunk_i->bytes_per_block;
+
+    wav_master_chunk_t mchunk = {
+        .file_size = sizeof(wav_master_chunk_t) + sizeof(wav_fmt_chunk_t) + sizeof(wav_data_t) + data_size_bytes
+    };
+
+    memcpy(&mchunk.chunk_id, "RIFF", 4);
+    memcpy(&mchunk.file_format_id, "WAVE", 4);
+
+    fwrite(&mchunk, sizeof(wav_master_chunk_t), 1, wav_file);
+    fwrite(fmt_chunk_i, sizeof(wav_data_t), 1, wav_file);
+    fwrite(data_i.samples, sizeof(u8), data_size_bytes, wav_file);
+
+    return true;
+}
+
+wav_fmt_chunk_t make_wav_fmt_chunk(u32 num_channels, u32 sample_rate, u16 bits_per_sample, wav_data_t data_i) {
+    u64 data_size_bytes = data_i.sample_count * (num_channels * (bits_per_sample / 8));
+    wav_fmt_chunk_t o = {
+        .chunk_size = sizeof(wav_fmt_chunk_t) + data_size_bytes - 8,
+        .bits_per_sample = bits_per_sample,
+        .num_channels = num_channels,
+        .sample_rate = sample_rate,
+        .bytes_per_block = num_channels * (bits_per_sample / 8),
+        .audio_format = 1,
+    };
+    o.bytes_per_sec = o.bytes_per_block * sample_rate;
+    memcpy(&o.chunk_id, "data", 4);
+
+    return o;
+}