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authorPetteri Hintsanen <petterih@iki.fi>2021-02-10 23:53:29 +0200
committerPetteri Hintsanen <petterih@iki.fi>2021-02-10 23:53:29 +0200
commit0f11ae182ceb12bcbbbac041af74585ac182c514 (patch)
tree72e87d8f77117d05027fe1502226521010256aba
parent6e5d477316da03f2203cc934ebf774ff78403f29 (diff)
Reorder functions and constants
Constructs are now ordered from generic to specific ("top-down") and are thus, hopefully, easier to follow.
-rw-r--r--emms-info-native.el150
1 files changed, 73 insertions, 77 deletions
diff --git a/emms-info-native.el b/emms-info-native.el
index 91b3ff5..e0b3906 100644
--- a/emms-info-native.el
+++ b/emms-info-native.el
@@ -223,10 +223,39 @@ exhaustion in case of garbled or malicious inputs.
This limit is used with Opus and FLAC streams as well, since
their comments have almost the same format as Vorbis.")
+(defconst emms-info-native--accepted-vorbis-fields
+ '("album"
+ "albumartist"
+ "albumartistsort"
+ "albumsort"
+ "artist"
+ "artistsort"
+ "composer"
+ "composersort"
+ "date"
+ "discnumber"
+ "genre"
+ "label"
+ "originaldate"
+ "originalyear"
+ "performer"
+ "title"
+ "titlesort"
+ "tracknumber"
+ "year")
+ "Emms info fields that are extracted from Vorbis comments.")
+
(defconst emms-info-native--vorbis-magic-array
[118 111 114 98 105 115]
"Header packet magic pattern ‘vorbis’.")
+(defconst emms-info-native--vorbis-headers-bindat-spec
+ '((identification-header struct emms-info-native--vorbis-identification-header-bindat-spec)
+ (comment-header struct emms-info-native--vorbis-comment-header-bindat-spec))
+ "Specification for first two Vorbis header packets.
+They are always an identification header followed by a comment
+header.")
+
(defconst emms-info-native--vorbis-identification-header-bindat-spec
'((packet-type u8)
(eval (unless (= last 1)
@@ -287,35 +316,6 @@ their comments have almost the same format as Vorbis.")
(user-comment vec (length)))
"Vorbis comment field specification.")
-(defconst emms-info-native--vorbis-headers-bindat-spec
- '((identification-header struct emms-info-native--vorbis-identification-header-bindat-spec)
- (comment-header struct emms-info-native--vorbis-comment-header-bindat-spec))
- "Specification for first two Vorbis header packets.
-They are always an identification header followed by a comment
-header.")
-
-(defconst emms-info-native--accepted-vorbis-fields
- '("album"
- "albumartist"
- "albumartistsort"
- "albumsort"
- "artist"
- "artistsort"
- "composer"
- "composersort"
- "date"
- "discnumber"
- "genre"
- "label"
- "originaldate"
- "originalyear"
- "performer"
- "title"
- "titlesort"
- "tracknumber"
- "year")
- "Emms info fields that are extracted from Vorbis comments.")
-
(defun emms-info-native--extract-vorbis-comments (user-comments)
"Return a decoded list of comments from USER-COMMENTS.
USER-COMMENTS should be a list of Vorbis comments according to
@@ -369,11 +369,12 @@ outside itself.")
[79 112 117 115 84 97 103 115]
"Opus comment header magic pattern ‘OpusTags’.")
-(defconst emms-info-native--opus-channel-mapping-table
- '((stream-count u8)
- (coupled-count u8)
- (channel-mapping vec (eval emms-info-native--opus-channel-count)))
- "Opus channel mapping table specification.")
+(defconst emms-info-native--opus-headers-bindat-spec
+ '((identification-header struct emms-info-native--opus-identification-header-bindat-spec)
+ (comment-header struct emms-info-native--opus-comment-header-bindat-spec))
+ "Specification for two first Opus header packets.
+They are always an identification header followed by a comment
+header.")
(defconst emms-info-native--opus-identification-header-bindat-spec
'((opus-head vec 8)
@@ -396,6 +397,12 @@ outside itself.")
(t (struct emms-info-native--opus-channel-mapping-table))))
"Opus identification header specification.")
+(defconst emms-info-native--opus-channel-mapping-table
+ '((stream-count u8)
+ (coupled-count u8)
+ (channel-mapping vec (eval emms-info-native--opus-channel-count)))
+ "Opus channel mapping table specification.")
+
(defconst emms-info-native--opus-comment-header-bindat-spec
'((opus-tags vec 8)
(eval (unless (equal last emms-info-native--opus-tags-magic-array)
@@ -415,13 +422,6 @@ outside itself.")
(struct emms-info-native--vorbis-comment-field-bindat-spec)))
"Opus comment header specification.")
-(defconst emms-info-native--opus-headers-bindat-spec
- '((identification-header struct emms-info-native--opus-identification-header-bindat-spec)
- (comment-header struct emms-info-native--opus-comment-header-bindat-spec))
- "Specification for two first Opus header packets.
-They are always an identification header followed by a comment
-header.")
-
;;;; FLAC code
(defconst emms-info-native--flac-metadata-block-header-bindat-spec
@@ -446,6 +446,20 @@ header.")
(struct emms-info-native--vorbis-comment-field-bindat-spec)))
"FLAC Vorbis comment block specification.")
+(defun emms-info-native--decode-flac-comments (filename)
+ "Read and decode comments from FLAC file FILENAME.
+Return comments in a list of (FIELD . VALUE) cons cells. Only
+FIELDs that are listed in
+‘emms-info-native--accepted-vorbis-fields’ are returned."
+ (unless (emms-info-native--has-flac-signature filename)
+ (error "Invalid FLAC stream"))
+ (let* ((block (emms-info-native--decode-flac-comment-block
+ filename))
+ (unpacked (bindat-unpack emms-info-native--flac-comment-block-bindat-spec
+ block))
+ (user-comments (bindat-get-field unpacked 'user-comments)))
+ (emms-info-native--extract-vorbis-comments user-comments)))
+
(defun emms-info-native--has-flac-signature (filename)
"Check for FLAC stream marker at the beginning of FILENAME.
Return t if there is a valid stream marker, nil otherwise."
@@ -483,20 +497,6 @@ Return the comment block data in a vector."
(setq offset end)))
comment-block)))
-(defun emms-info-native--decode-flac-comments (filename)
- "Read and decode comments from FLAC file FILENAME.
-Return comments in a list of (FIELD . VALUE) cons cells. Only
-FIELDs that are listed in
-‘emms-info-native--accepted-vorbis-fields’ are returned."
- (unless (emms-info-native--has-flac-signature filename)
- (error "Invalid FLAC stream"))
- (let* ((block (emms-info-native--decode-flac-comment-block
- filename))
- (unpacked (bindat-unpack emms-info-native--flac-comment-block-bindat-spec
- block))
- (user-comments (bindat-get-field unpacked 'user-comments)))
- (emms-info-native--extract-vorbis-comments user-comments)))
-
;;;; id3v2 (MP3) code
(defconst emms-info-native--id3v2-magic-array
@@ -550,24 +550,6 @@ FIELDs that are listed in
(3 . utf-8))
"id3v2 text encodings.")
-(defun emms-info-native--checked-id3v2-size (bytes)
- "Calculate id3v2 element size from BYTES and check its validity.
-Return the size. Signal an error if the size exceeds
-‘emms-info-native--max-peek-size’."
- (let ((size (emms-info-native--decode-id3v2-size bytes)))
- (when (or (= size 0)
- (> size emms-info-native--max-peek-size))
- (error "id3v2 tag/header/frame size %s is invalid" bytes))
- size))
-
-(defun emms-info-native--decode-id3v2-size (bytes)
- "Decode id3v2 element size from BYTES.
-BYTES are interpreted as 7-bit bytes, MSB first. Return the
-size."
- (apply '+ (seq-map-indexed (lambda (elt idx)
- (* (expt 2 (* 7 idx)) elt))
- (reverse bytes))))
-
(defun emms-info-native--decode-id3v2 (filename)
"Read and decode id3v2 metadata from FILENAME.
Return metadata in a list of (FIELD . VALUE) cons cells. See
@@ -604,6 +586,22 @@ Return the size. Signal an error if the size exceeds
(insert-file-contents-literally filename nil 10 14)
(emms-info-native--checked-id3v2-size (buffer-string))))
+(defun emms-info-native--checked-id3v2-size (bytes)
+ "Calculate id3v2 element size from BYTES and check its validity.
+Return the size."
+ (let ((size (emms-info-native--decode-id3v2-size bytes)))
+ (when (or (= size 0) (> size emms-info-native--max-peek-size))
+ (error "id3v2 tag/header/frame size %s is invalid" bytes))
+ size))
+
+(defun emms-info-native--decode-id3v2-size (bytes)
+ "Decode id3v2 element size from BYTES.
+BYTES are interpreted as 7-bit bytes, MSB first. Return the
+size."
+ (apply '+ (seq-map-indexed (lambda (elt idx)
+ (* (expt 2 (* 7 idx)) elt))
+ (reverse bytes))))
+
(defun emms-info-native--decode-id3v2-frames (filename begin end)
"Read and decode id3v2 text frames from FILENAME.
BEGIN should be the offset of first byte after id3v2 header and
@@ -625,8 +623,7 @@ Return metadata in a list of (FIELD . VALUE) cons cells. See
(comment (emms-info-native--decode-id3v2-text-frame
frame)))
(when comment (push comment comments))
- (cl-incf offset (+ (bindat-get-field frame 'size)
- 10))))
+ (cl-incf offset (+ (bindat-get-field frame 'size) 10))))
(error nil))
comments)))
@@ -639,8 +636,7 @@ identifier and VALUE is the decoded text. Otherwise return nil."
(let ((info-id (emms-info-native--id3v2-frame-info-id frame))
(payload (bindat-get-field frame 'payload)))
(when info-id
- (cons info-id
- (emms-info-native--decode-id3v2-string payload)))))
+ (cons info-id (emms-info-native--decode-id3v2-string payload)))))
(defun emms-info-native--id3v2-frame-info-id (frame)
"Return the emms-info identifier for FRAME.