1/*
2**
3** Copyright 2007, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#define LOG_TAG "ResampleInputStream"
19#include "utils/Log.h"
20
21#include <media/mediarecorder.h>
22#include <stdio.h>
23#include <assert.h>
24#include <limits.h>
25#include <unistd.h>
26#include <fcntl.h>
27#include <utils/threads.h>
28
29#include "jni.h"
30#include "JNIHelp.h"
31#include "android_runtime/AndroidRuntime.h"
32
33
34// ----------------------------------------------------------------------------
35
36using namespace android;
37
38
39#define FIR_COEF(coef) (short)(0x10000 * coef)
40static const short fir21[] = {
41    FIR_COEF(-0.006965742326),
42    FIR_COEF(-0.008428945737),
43    FIR_COEF( 0.004241280174),
44    FIR_COEF( 0.022141096893),
45    FIR_COEF( 0.018765669437),
46    FIR_COEF(-0.009871891152),
47    FIR_COEF(-0.024842433247),
48    FIR_COEF( 0.006121772058),
49    FIR_COEF( 0.045890841611),
50    FIR_COEF( 0.021573503509),
51    FIR_COEF(-0.059681984668),
52    FIR_COEF(-0.076036275138),
53    FIR_COEF( 0.072405390275),
54    FIR_COEF( 0.308255674582),
55    FIR_COEF( 0.424321210495),
56    FIR_COEF( 0.308255674582),
57    FIR_COEF( 0.072405390275),
58    FIR_COEF(-0.076036275138),
59    FIR_COEF(-0.059681984668),
60    FIR_COEF( 0.021573503509),
61    FIR_COEF( 0.045890841611),
62    FIR_COEF( 0.006121772058),
63    FIR_COEF(-0.024842433247),
64    FIR_COEF(-0.009871891152),
65    FIR_COEF( 0.018765669437),
66    FIR_COEF( 0.022141096893),
67    FIR_COEF( 0.004241280174),
68    FIR_COEF(-0.008428945737),
69    FIR_COEF(-0.006965742326)
70};
71static const int nFir21 = sizeof(fir21) / sizeof(fir21[0]);
72
73static const int BUF_SIZE = 2048;
74
75
76static void android_media_ResampleInputStream_fir21(JNIEnv *env, jclass /* clazz */,
77         jbyteArray jIn,  jint jInOffset,
78         jbyteArray jOut, jint jOutOffset,
79         jint jNpoints) {
80
81    // safety first!
82    if (nFir21 + jNpoints * 2 > BUF_SIZE) {
83        jniThrowExceptionFmt(env, "java/lang/IllegalArgumentException",
84                "FIR+data too long %d", nFir21 + jNpoints);
85        return;
86    }
87
88    // get input data
89    short in[BUF_SIZE];
90    env->GetByteArrayRegion(jIn, jInOffset, (jNpoints * 2 + nFir21 - 1) * 2, (jbyte*)in);
91
92    // compute filter
93    short out[BUF_SIZE];
94    for (int i = 0; i < jNpoints; i++) {
95        long sum = 0;
96        const short* firp = &fir21[0];
97        const short* inp = &in[i * 2];
98        for (int n = nFir21; --n >= 0; ) {
99            sum += ((long)*firp++) * ((long)*inp++);
100        }
101        out[i] = (short)(sum >> 16);
102    }
103
104    // save new values
105    env->SetByteArrayRegion(jOut, jOutOffset, jNpoints * 2, (jbyte*)out);
106}
107
108// ----------------------------------------------------------------------------
109
110static const JNINativeMethod gMethods[] = {
111    {"fir21", "([BI[BII)V", (void*)android_media_ResampleInputStream_fir21},
112};
113
114
115int register_android_media_ResampleInputStream(JNIEnv *env)
116{
117    const char* const kClassPathName = "android/media/ResampleInputStream";
118
119    return AndroidRuntime::registerNativeMethods(env,
120            kClassPathName, gMethods, NELEM(gMethods));
121}
122