+/*
+ * Copyright (C) 2008 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file amp.c Paraslash's amplify filter. */
+
+#include "para.h"
+#include "amp_filter.cmdline.h"
+#include "list.h"
+#include "sched.h"
+#include "filter.h"
+#include "string.h"
+#include "error.h"
+
+/** The size of the output data buffer. */
+#define AMP_CHUNK_SIZE 40960
+
+extern char *stat_item_values[NUM_STAT_ITEMS];
+
+/** Data specific to the amplify filter. */
+struct private_amp_data {
+ /** Points to the configuration data for this instance of this filter. */
+ struct amp_filter_args_info *conf;
+ /** Amplification factor. */
+ unsigned amp;
+};
+
+static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
+{
+ size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
+ (fn->bufsize - fn->loaded) / 2 * 2);
+ struct private_amp_data *pad = fn->private_data;
+ int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
+
+ if (!length)
+ return 0;
+ for (i = 0; i < length / 2; i++) {
+ int x = (PARA_ABS(*ip) * (64 + pad->amp)) >> 6;
+ *op++ = *ip++ > 0? PARA_MIN(x, 32767) : PARA_MAX(-x, -32768);
+ }
+ fn->loaded += length;
+ return length;
+}
+
+static void amp_close(struct filter_node *fn)
+{
+ free(fn->private_data);
+ free(fn->buf);
+}
+
+static void *amp_parse_config(int argc, char **argv)
+{
+ struct amp_filter_args_info *conf = para_calloc(sizeof(*conf));
+
+ if (amp_cmdline_parser(argc, argv, conf))
+ goto err;
+ if (conf->amp_arg < 0)
+ goto err;
+ PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n", conf->amp_arg,
+ conf->amp_arg / 64.0 + 1.0);
+ return conf;
+err:
+ free(conf);
+ return NULL;
+}
+
+static void amp_open(struct filter_node *fn)
+{
+ struct private_amp_data *pad = para_calloc(sizeof(*pad));
+
+ pad->conf = fn->conf;
+ fn->private_data = pad;
+ if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION]) {
+ int i = SI_AMPLIFICATION;
+ char *s = stat_item_values[i] + strlen(status_item_list[i]) + 1;
+ sscanf(s, "%u", &pad->amp);
+ } else
+ pad->amp = pad->conf->amp_arg;
+ fn->bufsize = AMP_CHUNK_SIZE;
+ fn->buf = para_malloc(fn->bufsize);
+}
+
+/**
+ * The init function of the amplify filter.
+ *
+ * \param f Pointer to the struct to initialize.
+ */
+void amp_init(struct filter *f)
+{
+ f->open = amp_open;
+ f->close = amp_close;
+ f->convert = amp_convert;
+ f->print_help = amp_cmdline_parser_print_help;
+ f->parse_config = amp_parse_config;
+}