From c92652ecb1ad024020435b8038d8f83c400fcddd Mon Sep 17 00:00:00 2001
From: Antonius Hellmann <toni@rockbox.org>
Date: Tue, 14 Jul 2009 16:52:18 +0000
Subject: Collect encoder data chunks (usually < 1kB) before writing to disk.
 The reduced number of ci->write() calls give a nice write speedup to the mp3
 encoder.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21865 a1c6a512-1295-4272-9138-f99709370657
---
 apps/codecs/mp3_enc.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

(limited to 'apps')

diff --git a/apps/codecs/mp3_enc.c b/apps/codecs/mp3_enc.c
index 94d4c2a5f3..82a8620027 100644
--- a/apps/codecs/mp3_enc.c
+++ b/apps/codecs/mp3_enc.c
@@ -2390,6 +2390,9 @@ static inline bool is_file_data_ok(struct enc_file_event_data *filed)
     return filed->rec_file >= 0 && (long)filed->chunk->flags >= 0;
 } /* is_event_ok */
 
+static unsigned char mp3_data[16384] __attribute__((aligned(4)));
+static unsigned int  mp3_data_len; /* current data size in buffer */
+
 /* called very often - inline */
 static inline bool on_write_chunk(struct enc_file_event_data *data) ICODE_ATTR;
 static inline bool on_write_chunk(struct enc_file_event_data *data)
@@ -2405,9 +2408,20 @@ static inline bool on_write_chunk(struct enc_file_event_data *data)
         return true;
     }
 
-    if (ci->write(data->rec_file, data->chunk->enc_data,
-                  data->chunk->enc_size) != (ssize_t)data->chunk->enc_size)
-        return false;
+    /* if current chunk doesn't fit => write collected data */
+    if (mp3_data_len + data->chunk->enc_size > sizeof(mp3_data))
+    {
+        if (ci->write(data->rec_file, mp3_data,
+                    mp3_data_len) != (ssize_t)mp3_data_len)
+            return false;
+
+        mp3_data_len = 0;
+    }
+
+    memcpy(mp3_data+mp3_data_len, data->chunk->enc_data,
+           data->chunk->enc_size);
+
+    mp3_data_len += data->chunk->enc_size;
 
     data->num_pcm_samples += data->chunk->num_pcm;
     return true;
@@ -2425,6 +2439,10 @@ static bool on_start_file(struct enc_file_event_data *data)
 
     /* reset sample count */
     data->num_pcm_samples = 0;
+
+    /* reset buffer write position */
+    mp3_data_len = 0;
+
     return true;
 } /* on_start_file */
 
@@ -2433,6 +2451,14 @@ static bool on_end_file(struct enc_file_event_data *data)
     if (data->rec_file < 0)
         return false; /* file already closed, nothing more we can do */
 
+    /* write the remaining mp3_data */
+    if (ci->write(data->rec_file, mp3_data, mp3_data_len)
+                   != (ssize_t)mp3_data_len)
+        return false;
+
+    /* reset buffer write position */
+    mp3_data_len = 0;
+
     /* always _try_ to write the file header, even on error */
     if (ci->close(data->rec_file) != 0)
         return false;
-- 
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