fix: don't leak memory on the error path

- migrate to os2
- check if the streaminfo min and max block size are within range
- use a tracking allocator for the example program

TODO.md

@@ -13,17 +13,12 @@ uncommon/11 -> We error with Invalid Signature
 
 faulty/01 -> This one works when it shouldn't (Wrong max blocksize)
 faulty/02 -> This one works when it shouldn't (Wrong max framesize)
-faulty/04 -> This one works when it shouldn't. This one has a wrong number of channels (whatever that means)
-			 Each frame has to be played by itself, otherwise plays sped up.
-faulty/05 -> This one works when it shouldn't. (Wrong number of samples)
-			 This should be fine to decode and play.
-faulty/08 -> This one works when it shouldn't. (Blocksize 65536, exceeds the allowed max of 65535)
-			 We should error here. We segfault currently.
-faulty/09 -> This one works when it shouldn't. (Blocksize 1, below the allowed min of 16 (only the last frame is allowed to have less than 16))
-			 We should error here. We play correctly currently.
-faulty/11 -> We return an error now, but we should just warn and decode the audio fine.
 
 Things:-
+[ ] Seeking to arbitrary samples
+	- bufio `Reader` doesn't implement `.Seek` but the underlying `io.Stream` which is just a file DOES implement
+	  `.Seek` so I think bufio `Reader` should have Seeking capabilities too as long as the underlying Reader supports it.
+	  I could hack something together to (dis)prove this.
 [ ] Options
 	- [x] Vorbis comment data
 	- [ ] Cuesheet ?
@@ -33,6 +28,7 @@ Things:-
 [ ] Lots of checks (look at the TODOs in flac.odin)
 [x] Memory optimizations
 [ ] Speed optimizations
+	- Does this matter? So far I haven't found a FLAC file that lags while playing or stalls the audio device even without `-o:speed`
 [ ] Seeking
 [ ] Fuzzing to test the stability of the code
 [x] Check if the use-after-free bug happens on Windows, and if so, if the address sanitizer will show us the full stacktrace

example/main_linux.odin

@@ -1,4 +1,4 @@
-package flac_linux_example
+package flac_linux_alsa_example
 
 import "core:fmt"
 import "core:mem"
@@ -33,15 +33,19 @@ main :: proc() {
         fmt.eprintln("Failed to alloc memory")
         return
     }
-    allocator := virtual.arena_allocator(&arena)
+    //allocator := virtual.arena_allocator(&arena)
+
+    track: mem.Tracking_Allocator
+    mem.tracking_allocator_init(&track, context.allocator)
+    defer mem.tracking_allocator_destroy(&track)
+    context.allocator = mem.tracking_allocator(&track)
 
     start := time.now()
-    flac_data, reader, err := flac.load_from_file(os.args[1], allocator)
+    flac_data, reader, err := flac.load_from_file(os.args[1], context.allocator)
     if err != nil {
         fmt.println("Error while reading flac file:", err)
         os.exit(1)
     }
-    defer flac.destroy(flac_data, reader, allocator)
 
     fmt.println(flac_data)
 
@@ -57,7 +61,7 @@ main :: proc() {
     md5_ctx: md5.Context
     md5.init(&md5_ctx)
     for {
-        frame, err := flac.read_next_frame(reader, flac_data, allocator)
+        frame, err := flac.decode_next_frame(reader, flac_data, context.allocator)
         if err != nil {
             if err == .EOF {
                 break
@@ -123,4 +127,20 @@ main :: proc() {
 
     elapsed := time.diff(start, end)
     fmt.println("Decoding took", elapsed)
+
+    flac.destroy(flac_data, reader, context.allocator)
+
+    for _, leak in track.allocation_map {
+        fmt.printfln("%v leaked %m", leak.location, leak.size)
+    }
+    
+    for bad_free in track.bad_free_array {
+        fmt.printfln("%v allocation %p was freed badly", bad_free.location, bad_free.memory)
+    }
+    
+    fmt.printfln("Peak Mem: %m", track.peak_memory_allocated)
+    fmt.printfln("Total Mem: %m", track.total_memory_allocated)
+    fmt.printfln("Current Mem: %m", track.current_memory_allocated)
+    fmt.printfln("Total Allocs: %v, Total Frees: %v:", track.total_allocation_count, track.total_free_count)
+    fmt.printfln("Total Mem Free'd: %m", track.total_memory_freed)
 }

flac.odin

@@ -1,13 +1,11 @@
 package flac
 
-import "core:bytes"
 import "core:bufio"
 import "core:crypto/legacy/md5"
 import "core:fmt"
 import "core:io"
 import "core:mem"
 import "core:os"
-import "core:time"
 
 Error :: union {
     io.Error,
@@ -69,8 +67,8 @@ PictureType :: enum u32 {
 
 Flac :: struct {
     metadata: FlacMetadata,
-    // This holds the samples up to the currently decoded frame. If all frames have
+    // This holds the samples of the current frame.
-    // been decoded then this will hold all the decoded samples.
+	// TODO: Should this be deleted? every frame already holds its own samples data
     samples:  [dynamic]i32,
 }
 
@@ -94,14 +92,15 @@ Picture :: struct {
     height: u32,
     depth: u32,
     num_colors: u32,
-    data: []byte,
+    data: []byte `fmt:"-"`,
 }
 
 Frame :: struct {
     channels: u8,
     sample_rate: u32,
-    // A slice of `Flac`'s `samples` field.
+    // A slice view of `Flac`'s `samples` field.
     // Contains the frame's decoded samples.
+    // DO NOT FREE.
     samples: []i32,
 }
 
@@ -430,12 +429,27 @@ correlate :: proc(subframes: [][]i32, channel_assignment: ChannelAssignment) {
 }
 
 @(private)
-read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (flac: ^Flac, err: Error) {
+read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (out_flac: ^Flac, err: Error) {
+    context.allocator = allocator
+
+    /* Held in a local rather than in the named result: an Odin `defer` cannot
+     change a named result, so the unwind below is able to free this but not to
+     nil it out for the caller. Assigning it only on the successful return means
+     every error path hands back nil instead of a freed pointer.
+    */
+    flac: ^Flac
+
     header := read_data(r, FlacHeader) or_return
     if header.magic != FLAC_MAGIC {
         return nil, .Invalid_Signature
     }
 
+	if (header.streaminfo.min_block_size < 16 || header.streaminfo.min_block_size > 65535)  ||
+		(header.streaminfo.max_block_size < 16 || header.streaminfo.max_block_size > 65535) ||
+		(header.streaminfo.min_block_size > header.streaminfo.max_block_size) {
+		return nil, .Invalid_Block_Size
+	}
+
     sample_rate := header.streaminfo.sr_chan_bps_ts >> 44
     num_channel_minus_one := (header.streaminfo.sr_chan_bps_ts >> 41) & 7
     bits_per_sample_minus_one := (header.streaminfo.sr_chan_bps_ts >> 36) & 0x1F
@@ -448,7 +462,7 @@ read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (flac: ^Fla
     }
 
     if streaminfo_header.type != .STREAMINFO {
-        return flac, .Missing_StreamInfo
+        return nil, .Missing_StreamInfo
     }
 
     if flac == nil {
@@ -462,6 +476,30 @@ read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (flac: ^Fla
     flac.metadata.expected_md5 = header.streaminfo.md5
 
     pictures := make([dynamic]Picture, 0, 2, allocator)
+
+    /* Everything allocated from here on hangs off `flac`, and a caller that gets
+     an error back is handed a nil `flac` -- so it has nothing to pass to
+     `destroy` and cannot clean any of this up itself. Unwind it here instead.
+     Each block below therefore hands its allocations to `flac` or to `pictures`
+     as soon as they exist, before the next read that could fail.
+    */
+    defer if err != nil {
+        for picture in pictures {
+            delete(picture.mimetype)
+            delete(picture.description)
+            delete(picture.data)
+        }
+        delete(pictures)
+
+        for comment in flac.metadata.vorbis_comments {
+            delete(comment)
+        }
+        delete(flac.metadata.vorbis_comments)
+        delete(flac.metadata.vendor_name)
+
+        free(flac)
+    }
+
     last_block := streaminfo_header.last_block
     for !last_block {
         md_block_hdr := read_data(r, u32be) or_return
@@ -501,26 +539,33 @@ read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (flac: ^Fla
                     fmt.eprintfln("Expected size: %d, Got %d", metadata_block_header.length, actual_size)
                 }
             case .VORBIS_COMMENT:
+                // A stream may carry more than one of these; the last one wins,
+                // so release the previous block rather than orphaning it.
+                for comment in flac.metadata.vorbis_comments {
+                    delete(comment)
+                }
+                delete(flac.metadata.vorbis_comments)
+                delete(flac.metadata.vendor_name)
+                flac.metadata.vorbis_comments = nil
+                flac.metadata.vendor_name = ""
+
                 vendor_name_len := read_data(r, u32le) or_return
                 vendor_name_slice := make([]byte, vendor_name_len)
+                flac.metadata.vendor_name = string(vendor_name_slice)
                 read_slice(r, vendor_name_slice) or_return
-                vendor_name := string(vendor_name_slice)
                 user_comment_list_len := read_data(r, u32le) or_return
 
                 actual_size := 4 + vendor_name_len + 4
 
                 comments := make([]string, user_comment_list_len)
+                flac.metadata.vorbis_comments = comments
                 for i in 0..<user_comment_list_len {
                     comment_len := read_data(r, u32le) or_return
                     comment_slice := make([]byte, comment_len)
+                    comments[i] = string(comment_slice)
                     read_slice(r, comment_slice) or_return
-                    comment := string(comment_slice)
                     actual_size += 4 + comment_len
-
-                    comments[i] = comment
                 }
-                flac.metadata.vorbis_comments = comments
-                flac.metadata.vendor_name = vendor_name
                 if metadata_block_header.length != u32(actual_size) {
                     fmt.eprintln("Vorbis metadata header length mismatch!")
                     fmt.eprintfln("Expected size: %d, Got %d", metadata_block_header.length, actual_size)
@@ -532,7 +577,7 @@ read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (flac: ^Fla
                 cuesheet := read_data(r, CueSheet) or_return
                 if cuesheet.num_tracks < 1 {
                     // TODO: should this be a warning instead of an error that halts the decoding?
-                    return flac, .Missing_Lead_Out_Track
+                    return nil, .Missing_Lead_Out_Track
                 }
                 //fmt.println(cuesheet)
                 for i in 0..<cuesheet.num_tracks {
@@ -546,15 +591,20 @@ read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (flac: ^Fla
             case .PICTURE:
                 pic_type := PictureType(read_data(r, u32be) or_return)
                 mime_len := read_data(r, u32be) or_return
+                // These three are only reachable through `pictures` once the
+                // append below runs, so they need their own unwind until then.
                 mimetype_slice := make([]byte, mime_len)
+                defer if err != nil {delete(mimetype_slice)}
                 read_slice(r, mimetype_slice) or_return
                 mimetype := string(mimetype_slice)
                 desc_len := read_data(r, u32be) or_return
                 desc_slice := make([]byte, desc_len)
+                defer if err != nil {delete(desc_slice)}
                 read_slice(r, desc_slice) or_return
                 desc := string(desc_slice)
                 metadata := read_data(r, PictureMetadata) or_return
                 data := make([]byte, metadata.data_len)
+                defer if err != nil {delete(data)}
                 read_slice(r, data) or_return
                 picture := Picture{
                     type = pic_type,
@@ -583,7 +633,7 @@ read_metadata :: proc(r: ^Reader, allocator := context.allocator) -> (flac: ^Fla
     return flac, nil
 }
 
-read_next_frame :: proc(r: ^Reader, flac: ^Flac, allocator := context.allocator) -> (frame: Frame, err: Error) {
+decode_next_frame :: proc(r: ^Reader, flac: ^Flac, allocator := context.allocator) -> (frame: Frame, err: Error) {
     //
     // Frame Header
     //
@@ -652,6 +702,14 @@ read_next_frame :: proc(r: ^Reader, flac: ^Flac, allocator := context.allocator)
             return {}, .Invalid_Block_Size
     }
 
+    // TODO: Any frame but the last one MUST have a block size equal to or greater
+    // than the minimum block size and MUST have a block size equal to or
+    // less than the maximum block size.  The last frame MUST have a block
+    // size equal to or less than the maximum block size; it does not have
+    // to comply to the minimum block size because the block size of that
+    // frame must be able to accommodate the length of the audio data the
+    // stream contains
+    //
     //if actual_block_size < 15 && !last_frame {
         // TODO: block sizes less than 16 are only valid for the last frame and MUST NOT be used for any other frame.
     //}
@@ -780,7 +838,7 @@ read_next_frame :: proc(r: ^Reader, flac: ^Flac, allocator := context.allocator)
 
     correlate(subframes, channel_assignment)
 
-    start := len(flac.samples)
+    clear(&flac.samples)
 
     // Write the samples interleaved.
     for i in 0..<len(subframes[0]) {
@@ -794,7 +852,7 @@ read_next_frame :: proc(r: ^Reader, flac: ^Flac, allocator := context.allocator)
         delete(subframe)
     }
 
-    frame.samples = flac.samples[start:]
+    frame.samples = flac.samples[:]
     frame.channels = frame_channels
     frame.sample_rate = actual_sample_rate_in_Hz
 
@@ -856,33 +914,47 @@ md5sum :: proc(md5_ctx: ^md5.Context, flac: ^Flac) -> Error {
 }
 
 // `load_from_file` initializes a buffered reader for the file and reads all the metadata blocks.
-// Calls to `read_next_frame()` MUST be made to decode the audio data.
+// Calls to `decode_next_frame()` MUST be made to decode the audio data.
 // This is the recommended way to read most FLAC files as it has a minimal memory overhead.
 load_from_file :: proc(filename: string, allocator := context.allocator) -> (flac: ^Flac, r: ^Reader, err: Error) {
     context.allocator = allocator
 
     file, open_err := os.open(filename)
-    if open_err != os.ERROR_NONE {
+    if open_err != nil {
         fmt.eprintln(open_err)
-        return nil, {}, .Unable_To_Read_File
+        return nil, nil, .Unable_To_Read_File
     }
 
     br := new(bufio.Reader)
-    bufio.reader_init(br, os.stream_from_handle(file))
+    bufio.reader_init(br, os.to_stream(file))
 
-    r = new(Reader)
+    reader := new(Reader)
-    r.r = bufio.reader_to_stream(br)
+    reader.r = bufio.reader_to_stream(br)
-    r.buf = 0
+    reader.buf = 0
-    r.x = 0
+    reader.x = 0
-    r.n = 0
+    reader.n = 0
 
-    flac = read_metadata(r) or_return
+    /* Without this an unreadable file in a scanned library burns an fd and the
+     reader's 4 KB buffer on every attempt -- the caller is handed nil for both
+     results and so has no handle to close the file with.
+     `reader` is a local for the same reason `read_metadata` keeps one: a defer
+     cannot nil out the named result, so `r` is only assigned on success.
+    */
+    defer if err != nil {
+        bufio.reader_destroy(br)
+        free(br)
+        free(reader)
+        os.close(file)
+    }
 
-    return flac, r, nil
+    flac = read_metadata(reader) or_return
+
+    return flac, reader, nil
 }
 
 /* `destroy` cleans up and frees the memory allocated by all 3 loading functions.
  The returned reader from `load_from_file` MUST be passed to `destroy` in order to close the file handle.
+ Both arguments may be nil, so it is safe to defer immediately after a load.
  ---
  The allocator that was used when loading the flac file MUST be passed to `destroy` in order to properly free
  the memory, otherwise a bad free may occur and crash the program.
@@ -890,21 +962,25 @@ load_from_file :: proc(filename: string, allocator := context.allocator) -> (fla
 destroy :: proc(flac: ^Flac, r: ^Reader = nil, allocator := context.allocator) {
     context.allocator = allocator
 
-    delete(flac.samples)
+    // Tolerates a nil `flac` so a caller can `defer destroy(...)` straight after
-    for picture in flac.metadata.pictures {
+    // a load without first checking whether the load succeeded.
-        delete(picture.mimetype)
+    if flac != nil {
-        delete(picture.data)
+        delete(flac.samples)
-        delete(picture.description)
+        for picture in flac.metadata.pictures {
-    }
+            delete(picture.mimetype)
-    delete(flac.metadata.pictures)
+            delete(picture.data)
+            delete(picture.description)
+        }
+        delete(flac.metadata.pictures)
 
-    for comment in flac.metadata.vorbis_comments {
+        for comment in flac.metadata.vorbis_comments {
-        delete(comment)
+            delete(comment)
-    }
+        }
-    delete(flac.metadata.vorbis_comments)
+        delete(flac.metadata.vorbis_comments)
-    delete(flac.metadata.vendor_name)
+        delete(flac.metadata.vendor_name)
 
-    free(flac)
+        free(flac)
+    }
 
     if r != nil {
         br := cast(^bufio.Reader)r.data

internal.odin

@@ -212,10 +212,10 @@ CueSheet :: struct #packed {
     media_catalog_num:   [128]byte,
     num_lead_in_samples: u64be,
     using _:             bit_field u8 {
-        reserved:     u8   | 7,
+        reserved_1:     u8   | 7,
         compact_disc: bool | 1,
     },
-    reserved:            [258]byte,
+    reserved_2:            [258]byte,
     num_tracks:          u8,
 }
 
@@ -225,11 +225,11 @@ CueSheetTrack :: struct #packed {
     track_num:              u8,
     ISRC:                   [12]byte,
     using _:                bit_field u8 {
-        reserved:     u8        | 6,
+        reserved_1:     u8        | 6,
         pre_emphasis: bool      | 1,
         track_type:   TrackType | 1,
     },
-    reserved:               [13]byte,
+    reserved_2:               [13]byte,
     num_track_index_points: u8,
 }
 
@@ -240,6 +240,7 @@ CueSheetTrackIndex :: struct #packed {
     reserved:           [3]byte,
 }
 
+@(optimization_mode="favor_size")
 decode_extended_utf8 :: proc(r: ^Reader) -> (decoded_num: u64, err: Error) {
     MASKX :: 0b0011_1111
     MASK2 :: 0b0001_1111

reader.odin

@@ -1,4 +1,3 @@
-#+private
 package flac
 
 import "core:io"
@@ -6,6 +5,8 @@ import "core:io"
 /* Basic byte and bit reader.
  Uses core:bytes reader under the hood with a few useful procedures for reading structs and other types.
 */
+// Public because load_from_file hands one back; everything else in this file
+// stays package-private.
 Reader :: struct {
     using r: io.Stream,
     // Temporary read buffer.
@@ -33,6 +34,7 @@ read_data :: #force_inline proc(r: ^Reader, $T: typeid) -> (res: T, err: io.Erro
 // Read reads and returns the next n bits, at most 64. It buffers bits up to the
 // next byte boundary.
 // Borrowed from https://github.com/mewkiz/flac
+@(private)
 read_bits :: proc(r: ^Reader, n: uint) -> (res: u64, err: io.Error) #no_bounds_check {
     if n == 0 {
         return 0, nil
@@ -86,6 +88,7 @@ read_bits :: proc(r: ^Reader, n: uint) -> (res: u64, err: io.Error) #no_bounds_c
     return res, nil
 }
 
+@(private)
 align_to_byte :: proc(r: ^Reader) {
     r.x = 0
     r.n = 0

tests/flac_test.odin

@@ -3,6 +3,7 @@ package flac_test
 import "core:fmt"
 import "core:os"
 import "core:testing"
+import "core:crypto/legacy/md5"
 import "shared:flac"
 
 @(test)
@@ -12,7 +13,7 @@ test_blocksize_4096 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Read Blocksize 4096 metadata Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -27,7 +28,7 @@ test_blocksize_4608 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 4608 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -42,7 +43,7 @@ test_blocksize_16 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 16 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -57,7 +58,7 @@ test_blocksize_192 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 192 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -72,7 +73,7 @@ test_blocksize_254 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 254 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -87,7 +88,7 @@ test_blocksize_512 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 512 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -102,7 +103,7 @@ test_blocksize_725 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 725 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -117,7 +118,7 @@ test_blocksize_1000 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 1000 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -132,7 +133,7 @@ test_blocksize_1937 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 1937 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -147,7 +148,7 @@ test_blocksize_2304 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Blocksize 2304 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -162,7 +163,7 @@ test_partition_order_8 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Partition order 8 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -177,7 +178,7 @@ test_qlp_precision_15_bit :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("qlp precision 15 bit Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -192,7 +193,7 @@ test_qlp_precision_2_bit :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("qlp precision 2 bit Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -207,7 +208,7 @@ wasted_bits :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Wasted bits Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -222,7 +223,7 @@ only_verbatim_subframes :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Only verbatim subframes Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -241,7 +242,7 @@ partition_order_8_containing_escaped_partitions :: proc(t: ^testing.T) {
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -256,7 +257,7 @@ all_fixed_orders :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("All fixed orders Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -271,7 +272,7 @@ precision_search :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Precision search Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -286,7 +287,7 @@ samplerate_35467Hz :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Samplerate 35467Hz Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -301,7 +302,7 @@ samplerate_39kHz :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Samplerate 39kHz Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -316,7 +317,7 @@ samplerate_22050Hz :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Samplerate 22050Hz Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -331,7 +332,7 @@ _12_bit_per_sample :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("12 bit per sample Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -346,7 +347,7 @@ _8_bit_per_sample :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("8 bit per sample Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -367,7 +368,7 @@ variable_blocksize_file_created_with_flake_revision_264 :: proc(t: ^testing.T) {
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -391,7 +392,7 @@ variable_blocksize_file_created_with_flake_revision_264_modified_to_create_small
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -412,7 +413,7 @@ variable_blocksize_file_created_with_CUETools_Flake_2_1_6 :: proc(t: ^testing.T)
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -433,7 +434,7 @@ old_format_variable_blocksize_file_created_with_Flake_0_11 :: proc(t: ^testing.T
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -448,7 +449,7 @@ high_resolution_audio_default_settings :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("High resolution audio, default settings Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -463,7 +464,7 @@ high_resolution_audio_blocksize_16384 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("High resolution audio, blocksize 16384 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -478,7 +479,7 @@ high_resolution_audio_blocksize_13456 :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("High resolution audio, blocksize 13456 Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -499,7 +500,7 @@ high_resolution_audio_using_only_32nd_order_predictors :: proc(t: ^testing.T) {
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -520,7 +521,7 @@ high_resolution_audio_partition_order_8_containing_escaped_partitions :: proc(t:
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -535,7 +536,7 @@ samplerate_192kHz :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Samplerate 192kHz Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -554,7 +555,7 @@ samplerate_192kHz_using_only_32nd_order_predictors :: proc(t: ^testing.T) {
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -569,7 +570,7 @@ samplerate_134560Hz :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Samplerate 134560Hz Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -584,7 +585,7 @@ samplerate_384kHz :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Samplerate 384kHz Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -599,7 +600,7 @@ _20_bit_per_sample :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("20 bit per sample Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -614,7 +615,7 @@ _3_channels :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("3 channels Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -629,7 +630,7 @@ _4_channels :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("4 channels Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -644,7 +645,7 @@ _5_channels :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("5 channels Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -659,7 +660,7 @@ _6_channels :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("6 channels Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -674,7 +675,7 @@ _7_channels :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("7 channels Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -689,7 +690,7 @@ _8_channels :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("8 channels Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -710,7 +711,7 @@ _8_channel_surround_192kHz_24_bit_using_only_32nd_order_predictors :: proc(t: ^t
     )
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -725,7 +726,7 @@ no_total_number_of_samples :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("No total number of samples Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -740,7 +741,7 @@ no_min_max_framesize :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("No min-max framesize Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -755,7 +756,7 @@ only_streaminfo :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Only STREAMINFO Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -770,7 +771,7 @@ extreme_large_seektable :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Extremely large SEEKTABLE Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -785,7 +786,7 @@ extreme_large_padding :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Extremely large PADDING Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -800,7 +801,7 @@ extreme_large_picture :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Extremely large PICTURE Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -815,7 +816,7 @@ extreme_large_vorbiscomment :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Extremely large VORBISCOMMENT Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -830,7 +831,7 @@ extreme_large_application :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Extremely large APPLICATION Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -845,7 +846,7 @@ cuesheet_with_very_many_indexes :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("CUESHEET with very many indexes Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -860,7 +861,7 @@ _1000x_repeating_vorbiscomment :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("1000x repeating VORBSICOMMENT Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -875,7 +876,7 @@ file_48_53_combined :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("File 48-53 combined Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -890,7 +891,7 @@ jpg_picture :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("JPG PICTURE Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -905,7 +906,7 @@ png_picture :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("PNG PICTURE Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -920,7 +921,7 @@ gif_picture :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("GIF PICTURE Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -935,7 +936,7 @@ avif_picture :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("AVIF PICTURE Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -950,7 +951,7 @@ mono_audio :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Mono audio Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -965,7 +966,7 @@ predictor_overflow_check_16_bit :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Predictor overflow check, 16-bit Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -980,7 +981,7 @@ predictor_overflow_check_20_bit :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Predictor overflow check, 20-bit Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -995,7 +996,7 @@ predictor_overflow_check_24_bit :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Predictor overflow check, 24-bit Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -1010,7 +1011,7 @@ rice_partitions_with_escape_code_zero :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Rice partitions with escape code zero Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -1018,6 +1019,29 @@ rice_partitions_with_escape_code_zero :: proc(t: ^testing.T) {
 	}
 }
 
+@(test)
+uncommon_changing_samplerate :: proc(t: ^testing.T) {
+	data, r, err := flac.load_from_file("flac-test-files/uncommon/01 - changing samplerate.flac")
+	defer flac.destroy(data, r)
+	testing.expect(t, err == nil, fmt.tprint("Uncommon changing samplerate Failed with error:", err))
+
+    md5_ctx: md5.Context
+    md5.init(&md5_ctx)
+
+	for {
+		frame, f_err := flac.decode_next_frame(r, data)
+		if f_err == .EOF {
+			break
+		}
+		flac.md5hash(&md5_ctx, data.metadata.bits_per_sample, frame.samples)
+		testing.expect(t, f_err == nil, fmt.tprintf("Decoding Uncommon changing samplerate frame Failed with error:", f_err))
+	}
+
+	if data.metadata.expected_md5 != 0 {
+		testing.expect(t, flac.md5sum(&md5_ctx, data) == nil, fmt.tprintf("Incorrect MD5 hash. Expected %v. Got %v", data.metadata.expected_md5, data.metadata.calculated_md5))
+	}
+}
+
 @(test)
 uncommon_32_bit_per_sample :: proc(t: ^testing.T) {
     data, r, err := flac.load_from_file("flac-test-files/uncommon/05 - 32bps audio.flac")
@@ -1025,7 +1049,7 @@ uncommon_32_bit_per_sample :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Uncommon 32bps audio Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}
@@ -1040,7 +1064,7 @@ uncommon_samplerate_768kHz :: proc(t: ^testing.T) {
     testing.expect(t, err == nil, fmt.tprint("Uncommon samplerate 768kHz Failed with error:", err))
 
 	for {
-		frame, f_err := flac.read_next_frame(r, data)
+		frame, f_err := flac.decode_next_frame(r, data)
 		if f_err == .EOF {
 			break
 		}