buffering: remove bufgettail/bufcuttail

These operations can only be used in limited circumstances and have
exactly one user. bufgettail especially seems of dubious value; how
often do you need to read N bytes from the end of a file without
changing the file position?

strip_tags() was the only function using them, to strip off ID3v1
and APE tags off the end of buffered tracks. This would save only
32-192 bytes per track -- if the container format uses APE/ID3v1.
It hardly seems worth the effort.

Change-Id: I8fc3c1408517eda6126e75e76d76daea904b50eb

6 files changed, 1 insertions, 119 deletions

diff --git a/apps/buffering.c b/apps/buffering.c
index db555d8805..8661a42ab8 100644
--- a/apps/buffering.c
+++ b/apps/buffering.c
@@ -1436,62 +1436,6 @@ ssize_t bufgetdata(int handle_id, size_t size, void **data)
     return size;
 }
 
-ssize_t bufgettail(int handle_id, size_t size, void **data)
-{
-    if (thread_self() != buffering_thread_id)
-        return ERR_WRONG_THREAD; /* only from buffering thread */
-
-    /* We don't support tail requests of > guardbuf_size, for simplicity */
-    if (size > GUARD_BUFSIZE)
-        return ERR_INVALID_VALUE;
-
-    const struct memory_handle *h = find_handle(handle_id);
-    if (!h)
-        return ERR_HANDLE_NOT_FOUND;
-
-    if (h->end >= h->filesize) {
-        size_t tidx = ringbuf_sub_empty(h->widx, size);
-
-        if (tidx + size > buffer_len) {
-            size_t copy_n = tidx + size - buffer_len;
-            memcpy(guard_buffer, ringbuf_ptr(0), copy_n);
-        }
-
-        *data = ringbuf_ptr(tidx);
-    }
-    else {
-        size = ERR_HANDLE_NOT_DONE;
-    }
-
-    return size;
-}
-
-ssize_t bufcuttail(int handle_id, size_t size)
-{
-    if (thread_self() != buffering_thread_id)
-        return ERR_WRONG_THREAD; /* only from buffering thread */
-
-    struct memory_handle *h = find_handle(handle_id);
-    if (!h)
-        return ERR_HANDLE_NOT_FOUND;
-
-    if (h->end >= h->filesize) {
-        /* Cannot trim to before read position */
-        size_t available = h->end - MAX(h->start, h->pos);
-        if (available < size)
-            size = available;
-
-        h->widx = ringbuf_sub_empty(h->widx, size);
-        h->filesize -= size;
-        h->end -= size;
-    } else {
-        size = ERR_HANDLE_NOT_DONE;
-    }
-
-    return size;
-}
-
-
 /*
 SECONDARY EXPORTED FUNCTIONS
 ============================
diff --git a/apps/buffering.h b/apps/buffering.h
index 1a75d865ae..bc47d6b1a1 100644
--- a/apps/buffering.h
+++ b/apps/buffering.h
@@ -46,8 +46,7 @@ enum data_type {
 #define ERR_FILE_ERROR          -4
 #define ERR_HANDLE_NOT_DONE     -5
 #define ERR_UNSUPPORTED_TYPE    -6
-#define ERR_WRONG_THREAD        -7
-#define ERR_BITMAP_TOO_LARGE    -8
+#define ERR_BITMAP_TOO_LARGE    -7
 
 /* Initialise the buffering subsystem */
 void buffering_init(void) INIT_ATTR;
@@ -68,8 +67,6 @@ bool buffering_reset(char *buf, size_t buflen);
  * bufftell  : Return the handle's file read position
  * bufread   : Copy data from a handle to a buffer
  * bufgetdata: Obtain a pointer for linear access to a "size" amount of data
- * bufgettail: Out-of-band get the last size bytes of a handle.
- * bufcuttail: Out-of-band remove the trailing 'size' bytes of a handle.
  *
  * NOTE: bufread and bufgetdata will block the caller until the requested
  * amount of data is ready (unless EOF is reached).
@@ -85,8 +82,6 @@ int bufadvance(int handle_id, off_t offset);
 off_t bufftell(int handle_id);
 ssize_t bufread(int handle_id, size_t size, void *dest);
 ssize_t bufgetdata(int handle_id, size_t size, void **data);
-ssize_t bufgettail(int handle_id, size_t size, void **data);
-ssize_t bufcuttail(int handle_id, size_t size);
 
 /***************************************************************************
  * SECONDARY FUNCTIONS
diff --git a/apps/playback.c b/apps/playback.c
index a56c6d17ec..7fdb302d71 100644
--- a/apps/playback.c
+++ b/apps/playback.c
@@ -3467,9 +3467,6 @@ static void buffer_event_finished_callback(unsigned short id, void *ev_data)
         break;
 
     case TYPE_PACKET_AUDIO:
-        /* Strip any useless trailing tags that are left. */
-        strip_tags(hid);
-        /* Fall-through */
     case TYPE_ATOMIC_AUDIO:
         LOGFQUEUE("buffering > audio Q_AUDIO_HANDLE_FINISHED: %d", hid);
         audio_queue_post(Q_AUDIO_HANDLE_FINISHED, hid);
diff --git a/docs/PLUGIN_API b/docs/PLUGIN_API
index 8814833959..963809a27a 100644
--- a/docs/PLUGIN_API
+++ b/docs/PLUGIN_API
@@ -211,13 +211,6 @@ bool bufclose(int handle_id)
     \return
     \description
 
-ssize_t bufcuttail(int handle_id, size_t size)
-    \group buffering API
-    \param handle_id
-    \param size
-    \return
-    \description
-
 ssize_t bufgetdata(int handle_id, size_t size, void **data)
     \group buffering API
     \param handle_id
@@ -226,14 +219,6 @@ ssize_t bufgetdata(int handle_id, size_t size, void **data)
     \return
     \description
 
-ssize_t bufgettail(int handle_id, size_t size, void **data)
-    \group buffering API
-    \param handle_id
-    \param size
-    \param data
-    \return
-    \description
-
 int bufopen(const char *file, size_t offset, enum data_type type)
     \group buffering API
     \param file
diff --git a/lib/rbcodec/metadata/metadata.c b/lib/rbcodec/metadata/metadata.c
index aec72db97f..19147ccdb3 100644
--- a/lib/rbcodec/metadata/metadata.c
+++ b/lib/rbcodec/metadata/metadata.c
@@ -458,44 +458,6 @@ bool get_metadata(struct mp3entry* id3, int fd, const char* trackname)
     return true;
 }
 
-#ifndef __PCTOOL__
-void strip_tags(int handle_id)
-{
-    static const unsigned char tag[] = "TAG";
-    static const unsigned char apetag[] = "APETAGEX";
-    size_t len, version;
-    void *tail;
-
-    if (bufgettail(handle_id, 128, &tail) != 128)
-        return;
-
-    if (memcmp(tail, tag, 3) == 0)
-    {
-        /* Skip id3v1 tag */
-        logf("Cutting off ID3v1 tag");
-        bufcuttail(handle_id, 128);
-    }
-
-    /* Get a new tail, as the old one may have been cut */
-    if (bufgettail(handle_id, 32, &tail) != 32)
-        return;
-
-    /* Check for APE tag (look for the APE tag footer) */
-    if (memcmp(tail, apetag, 8) != 0)
-        return;
-
-    /* Read the version and length from the footer */
-    version = get_long_le(&((unsigned char *)tail)[8]);
-    len = get_long_le(&((unsigned char *)tail)[12]);
-    if (version == 2000)
-        len += 32; /* APEv2 has a 32 byte header */
-
-    /* Skip APE tag */
-    logf("Cutting off APE tag (%ldB)", len);
-    bufcuttail(handle_id, len);
-}
-#endif /* ! __PCTOOL__ */
-
 #define MOVE_ENTRY(x) if (x) x += offset;
 
 void adjust_mp3entry(struct mp3entry *entry, void *dest, const void *orig)
diff --git a/lib/rbcodec/metadata/metadata.h b/lib/rbcodec/metadata/metadata.h
index 50fd5bac86..1a205a08eb 100644
--- a/lib/rbcodec/metadata/metadata.h
+++ b/lib/rbcodec/metadata/metadata.h
@@ -333,7 +333,6 @@ void wipe_mp3entry(struct mp3entry *id3);
 
 void fill_metadata_from_path(struct mp3entry *id3, const char *trackname);
 int get_audio_base_codec_type(int type);
-void strip_tags(int handle_id);
 bool rbcodec_format_is_atomic(int afmt);
 bool format_buffers_with_offset(int afmt);