Add new i2s_dump protocol decoder.

[libsigrokdecode.git] / decoders / i2s_dump / pd.py

diff --git a/decoders/i2s_dump/pd.py b/decoders/i2s_dump/pd.py
new file mode 100644 (file)
index 0000000..8f95a86
--- /dev/null
+++ b/decoders/i2s_dump/pd.py
@@ -0,0 +1,107 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2013 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+import sigrokdecode as srd
+import os
+import sys
+
+class Decoder(srd.Decoder):
+    api_version = 1
+    id = 'i2s_dump'
+    name = 'I2S dump'
+    longname = 'I2S dump'
+    desc = 'Output decoded I2S data to a file.'
+    license = 'gplv2+'
+    inputs = ['i2s']
+    outputs = []
+    probes = []
+    optional_probes = []
+    options = {
+        'format': ['File format for the output data', 'wav'],
+        'filename': ['File name for the output data', '-'],
+    }
+    annotations = []
+
+    def __init__(self, **kwargs):
+        self.wrote_header = False
+        self.f = None
+
+    def file_open(self, filename):
+        if filename == 'none':
+            return None
+        elif filename == '-':
+            return sys.stdout
+        else:
+            return open(filename, 'wb')
+
+    def start(self, metadata):
+        # A filename of 'none' is not allowed (has special meaning). A filename
+        # of '-' means 'stdout'.
+        self.f = self.file_open(self.options['filename'])
+
+    def report(self):
+        pass
+
+    # TODO: Lots of hard-coded fields in here.
+    def write_wav_header(self):
+        # Chunk descriptor
+        self.f.write(b'RIFF')
+        self.f.write(b'\x24\x80\x00\x00') # Chunk size (2084)
+        self.f.write(b'WAVE')
+
+        # Fmt subchunk
+        self.f.write(b'fmt ')
+        self.f.write(b'\x10\x00\x00\x00') # Subchunk size (16 bytes)
+        self.f.write(b'\x01\x00')         # Audio format (0x0001 == PCM)
+        self.f.write(b'\x02\x00')         # Number of channels (2)
+        self.f.write(b'\x44\xac\x00\x00') # Samplerate (44100)
+        self.f.write(b'\x88\x58\x01\x00') # Byterate (88200) TODO
+        self.f.write(b'\x04\x00')         # Blockalign (4)
+        self.f.write(b'\x10\x00')         # Bits per sample (16)
+
+        # Data subchunk
+        self.f.write(b'data')
+        self.f.write(b'\xff\xff\x00\x00') # Subchunk size (65535 bytes) TODO
+
+        self.f.flush()
+
+    def decode(self, ss, es, data):
+        ptype, pdata = data
+
+        if ptype != 'DATA':
+            return
+
+        channel, sample = pdata
+
+        if self.wrote_header == False:
+            self.write_wav_header()
+            self.wrote_header = True
+
+        # Output the next sample to 'filename'.
+        # TODO: Data: first left channel, then right channel.
+        if self.f != None:
+            # TODO: This currently assumes U32 samples, and converts to S16.
+            s = sample >> 16
+            if s >= 0x8000:
+                s -= 0x10000
+            lo, hi = s & 0xff, (s >> 8) & 0xff
+            self.f.write(bytes('%02x%02x' % (lo, hi), 'utf-8'))
+            self.f.flush()
+