paraslash 0.7.3

[paraslash.git] / check_wav.c

diff --git a/check_wav.c b/check_wav.c
index 80265472635d70b24be13b6723c0c26f56374fbe..3789f30aa5a20ef5433df83362a6be02563c8d17 100644 (file)
--- 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,
 };
 
@@ -37,7 +38,16 @@ struct check_wav_context {
        unsigned sample_rate;
 };
 
-void check_wav_pre_select(struct sched *s, struct check_wav_context *cwc)
+/**
+ * Request a minimal timeout if not idle.
+ *
+ * \param s The scheduler instance.
+ * \param cwc The buffer tree node is derived from this.
+ *
+ * If no data is available and the buffer tree node is not in error state, the
+ * function does nothing.
+ */
+void check_wav_pre_monitor(struct sched *s, struct check_wav_context *cwc)
 {
        int ret = btr_node_status(cwc->btrn, cwc->min_iqs, BTR_NT_INTERNAL);
        if (ret != 0)
@@ -95,7 +105,23 @@ out:
        return 1;
 }
 
-int check_wav_post_select(struct check_wav_context *cwc)
+/**
+ * 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_monitor(struct check_wav_context *cwc)
 {
        struct btr_node *btrn = cwc->btrn;
        unsigned char *a;
@@ -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);
@@ -160,11 +186,28 @@ 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_monitor() and \ref
+ * check_wav_post_monitor().
+ *
+ * \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)
 {
-       struct check_wav_context *cwc = para_calloc(sizeof(*cwc));
+       struct check_wav_context *cwc = zalloc(sizeof(*cwc));
 
        cwc->state = CWS_NEED_HEADER;
        cwc->min_iqs = WAV_HEADER_LEN;
@@ -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_monitor() has returned
+ * negative.
+ */
 void check_wav_shutdown(struct check_wav_context *cwc)
 {
        free(cwc);