X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=check_wav.c;h=89ebdacc0805e9575acea92d09ed3b2dd81ebac3;hp=80265472635d70b24be13b6723c0c26f56374fbe;hb=23ef2355fbdebce56083ec7a0ebb65a05c42e5dc;hpb=9c5fbc5dd8b53604d7e73fb6714ee2b5e3458866

diff --git a/check_wav.c b/check_wav.c
index 80265472..89ebdacc 100644
--- a/check_wav.c
+++ b/check_wav.c
@@ -1,8 +1,4 @@
-/*
- * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
 
 /** \file check_wav.c Detect and delete a wav header. */
 
@@ -15,13 +11,18 @@
 #include "buffer_tree.h"
 #include "error.h"
 #include "check_wav.h"
+#include "portable_io.h"
 
 /** Length of a standard wav header. */
 #define WAV_HEADER_LEN 44
 
+/** The possible states of a check_wav instance. */
 enum check_wav_state {
+	/** Initial state, less than \p WAV_HEADER_LEN bytes available. */
 	CWS_NEED_HEADER,
+	/** Wav hader was detected. */
 	CWS_HAVE_HEADER,
+	/** First part of the stream did not look like a wav header. */
 	CWS_NO_HEADER,
 };
 
@@ -37,6 +38,15 @@ struct check_wav_context {
 	unsigned sample_rate;
 };
 
+/**
+ * Set select timeout according to the given context.
+ *
+ * \param s Contains the timeval that should be set.
+ * \param cwc Contains a pointer to the buffer tree node.
+ *
+ * This requests a minimal timeout from the scheduler if btrn of \a cwc is not
+ * idle.
+ */
 void check_wav_pre_select(struct sched *s, struct check_wav_context *cwc)
 {
 	int ret = btr_node_status(cwc->btrn, cwc->min_iqs, BTR_NT_INTERNAL);
@@ -95,6 +105,22 @@ out:
 	return 1;
 }
 
+/**
+ * Filter out the wav header, pushdown everything else.
+ *
+ * \param cwc The context of this instance.
+ *
+ * This function looks at the first \p WAV_HEADER_SIZE bytes of the input queue
+ * of the btrn of \a cwc. If they look like a wav header, the function extracts
+ * the information of interest and swallows this part of the stream. Otherwise
+ * it is pushed down to all children. In either case the rest of the input is
+ * pushed down as well.
+ *
+ * Once the first part has been processed this way, the state of the instance
+ * changes from \p CWS_NEED_HEADER to \p CWS_HAVE_HEADER or \p CWS_NO_HEADER.
+ *
+ * \return Standard.
+ */
 int check_wav_post_select(struct check_wav_context *cwc)
 {
 	struct btr_node *btrn = cwc->btrn;
@@ -130,9 +156,9 @@ int check_wav_post_select(struct check_wav_context *cwc)
 	PARA_INFO_LOG("found wav header\n");
 	cwc->state = CWS_HAVE_HEADER;
 	/* Only set those values which have not already been set. */
-	cwc->channels = (unsigned)a[22];
-	cwc->sample_rate = a[24] + (a[25] << 8) + (a[26] << 16) + (a[27] << 24);
-	bps = a[34] + ((unsigned)a[35] << 8);
+	cwc->channels = a[22];
+	cwc->sample_rate = read_u32(a + 24);
+	bps = read_u16(a + 34);
 	if (bps != 8 && bps != 16) {
 		PARA_WARNING_LOG("%u bps not supported, assuming 16\n",
 			bps);
@@ -148,7 +174,7 @@ int check_wav_post_select(struct check_wav_context *cwc)
 	else
 		cwc->sample_format = (a[3] == 'F')?
 			SF_S16_LE : SF_S16_BE;
-	PARA_NOTICE_LOG("%dHz, %s, %s\n", cwc->sample_rate,
+	PARA_NOTICE_LOG("%uHz, %s, %s\n", cwc->sample_rate,
 		cwc->channels == 1? "mono" : "stereo",
 		sample_formats[cwc->sample_format]);
 	btr_consume(btrn, WAV_HEADER_LEN);
@@ -160,6 +186,23 @@ out:
 	return ret;
 }
 
+/**
+ * Allocate and set up a new check_wav instance.
+ *
+ * \param parent This buffer tree node will be the parent of the new node.
+ * \param child The child of the new node.
+ * \param params Default values and options.
+ * \param cw_btrn A pointer to the check wav node is returned here.
+ *
+ * This function also sets up the ->execute handler of the btrn so that all
+ * children of this node can figure out channel count, sample rate, etc.
+ *
+ * \return The (opaque) handle of the newly created check_wav instance. It is
+ * supposed to be passed to \ref check_wav_pre_select() and \ref
+ * check_wav_post_select().
+ *
+ * \sa \ref btr_new_node.
+ */
 struct check_wav_context *check_wav_init(struct btr_node *parent,
 		struct btr_node *child, struct wav_params *params,
 		struct btr_node **cw_btrn)
@@ -177,6 +220,14 @@ struct check_wav_context *check_wav_init(struct btr_node *parent,
 	return cwc;
 }
 
+/**
+ * Dellocate all ressources of a check_wav instance.
+ *
+ * \param cwc Determines the instance to shut down.
+ *
+ * This function may only be called after check_wav_post_select() has returned
+ * negative.
+ */
 void check_wav_shutdown(struct check_wav_context *cwc)
 {
 	free(cwc);