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-rw-r--r--emms-info-native.el92
1 files changed, 51 insertions, 41 deletions
diff --git a/emms-info-native.el b/emms-info-native.el
index ab5b6c0..039738c 100644
--- a/emms-info-native.el
+++ b/emms-info-native.el
@@ -564,20 +564,26 @@ outside itself.")
(defun emms-info-native--decode-id3v2 (filename)
"Read and decode id3v2 metadata from FILENAME.
-Return metadata in a list of (FIELD . VALUE) cons cells."
- (let* (emms-info-native--id3v2-version
- (header (emms-info-native--decode-id3v2-header filename))
- (tag-size (bindat-get-field header 'size))
- (unsync (memq 7 (bindat-get-field header 'flags)))
- (offset 10))
- (when (memq 6 (bindat-get-field header 'flags))
- ;; Skip the extended header.
- (cl-incf offset
- (emms-info-native--decode-id3v2-ext-header-size filename)))
- (emms-info-native--decode-id3v2-frames filename
- offset
- (+ tag-size 10)
- unsync)))
+Return metadata in a list of (FIELD . VALUE) cons cells, or nil
+in case of errors or if there were no known fields in FILENAME.
+
+See ‘emms-info-native--id3v2-frame-to-info’ for recognized
+fields."
+ (condition-case-unless-debug nil
+ (let* (emms-info-native--id3v2-version
+ (header (emms-info-native--decode-id3v2-header filename))
+ (tag-size (bindat-get-field header 'size))
+ (unsync (memq 7 (bindat-get-field header 'flags)))
+ (offset 10))
+ (when (memq 6 (bindat-get-field header 'flags))
+ ;; Skip the extended header.
+ (cl-incf offset
+ (emms-info-native--decode-id3v2-ext-header-size filename)))
+ (emms-info-native--decode-id3v2-frames filename
+ offset
+ (+ tag-size 10)
+ unsync))
+ (error nil)))
(defun emms-info-native--decode-id3v2-header (filename)
"Read and decode id3v2 header from FILENAME."
@@ -594,7 +600,7 @@ Return the size. Signal an error if the size exceeds
(with-temp-buffer
(set-buffer-multibyte nil)
(insert-file-contents-literally filename nil 10 14)
- (emms-info-native--checked-id3v2-size (buffer-string))))
+ (emms-info-native--checked-id3v2-size 'frame (buffer-string))))
(defun emms-info-native--checked-id3v2-size (elt bytes)
"Calculate id3v2 element ELT size from BYTES.
@@ -607,7 +613,7 @@ Return the size."
(if (= emms-info-native--id3v2-version 4)
(setq size (emms-info-native--decode-id3v2-size bytes t))
(setq size (emms-info-native--decode-id3v2-size bytes nil)))))
- (when (or (= size 0) (> size emms-info-native--max-peek-size))
+ (when (> size emms-info-native--max-peek-size)
(error "id3v2 tag or frame size %s is invalid" size))
size))
@@ -633,30 +639,34 @@ unsynchronization and decoded as such.
Return metadata in a list of (FIELD . VALUE) cons cells."
(let ((offset begin)
+ (limit (- end (emms-info-native--id3v2-frame-header-size)))
comments)
- (condition-case nil
- (while (< offset end)
- (let* ((header (emms-info-native--decode-id3v2-frame-header filename
- offset))
- (info-id (emms-info-native--id3v2-frame-info-id header))
- (decoded-size (bindat-get-field (cdr header) 'size)))
- (setq offset (car header)) ;advance to frame data begin
- (if (or unsync info-id)
- ;; Note that if unsync is t, we have to always read a
- ;; frame to gets its true size so that we can adjust
- ;; offset correctly.
- (let ((data (emms-info-native--read-id3v2-frame-data filename
- offset
- decoded-size
- unsync)))
- (setq offset (car data))
- (when info-id
- (let ((value (emms-info-native--decode-id3v2-string (cdr data))))
- (push (cons info-id value) comments))))
- ;; Skip the frame.
- (cl-incf offset decoded-size))))
- (error nil))
- comments))
+ (catch 'eof
+ (while (< offset limit)
+ (let* ((header (emms-info-native--decode-id3v2-frame-header filename
+ offset))
+ (info-id (emms-info-native--id3v2-frame-info-id header))
+ (decoded-size (bindat-get-field (cdr header) 'size)))
+ (when (= decoded-size 0) (throw 'eof t))
+ (setq offset (car header)) ;advance to frame data begin
+ (if (or unsync info-id)
+ ;; Note that if unsync is t, we have to always read a
+ ;; frame to gets its true size so that we can adjust
+ ;; offset correctly.
+ (let ((data (emms-info-native--read-id3v2-frame-data filename
+ offset
+ decoded-size
+ unsync)))
+ (setq offset (car data))
+ (when info-id
+ (let ((value (emms-info-native--decode-id3v2-string (cdr data))))
+ (push (cons info-id value) comments))))
+ ;; Skip the frame.
+ (cl-incf offset decoded-size)))))
+ comments))
+
+(defun emms-info-native--id3v2-frame-header-size ()
+ (if (= emms-info-native--id3v2-version 2) 6 10))
(defun emms-info-native--decode-id3v2-frame-header (filename begin)
"Read and decode id3v2 frame header from FILENAME.
@@ -666,7 +676,7 @@ Return a cons cell (OFFSET . FRAME), where OFFSET is the byte
offset after the frame header, and FRAME is the decoded frame."
(with-temp-buffer
(set-buffer-multibyte nil)
- (let ((end (+ begin (if (= emms-info-native--id3v2-version 2) 6 10))))
+ (let ((end (+ begin (emms-info-native--id3v2-frame-header-size))))
(insert-file-contents-literally filename nil begin end)
(cons end (bindat-unpack emms-info-native--id3v2-frame-header-bindat-spec
(buffer-string))))))
@@ -690,7 +700,7 @@ data."
(let ((peek-end (+ begin (* 2 num-bytes)))
(end num-bytes))
(insert-file-contents-literally filename nil begin peek-end)
- (beginning-of-buffer)
+ (goto-char (point-min))
(while (and (re-search-forward (string 255 0) nil t)
(< (point) end))
(replace-match (string 255))