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1 /* ------------------------------------------------------------------
2  * Copyright (C) 1998-2009 PacketVideo
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
13  * express or implied.
14  * See the License for the specific language governing permissions
15  * and limitations under the License.
16  * -------------------------------------------------------------------
17  */
18 /****************************************************************************************
19 Portions of this file are derived from the following 3GPP standard:
20 
21     3GPP TS 26.073
22     ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
23     Available from http://www.3gpp.org
24 
25 (C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
26 Permission to distribute, modify and use this file under the standard license
27 terms listed above has been obtained from the copyright holder.
28 ****************************************************************************************/
29 /*
30  Pathname: ./audio/gsm-amr/c/src/gmed_n.c
31 
32 ------------------------------------------------------------------------------
33  REVISION HISTORY
34 
35  Description: Put file into template and first pass at optimization.
36 
37  Description: Made changes based on comments from the review meeting. Used
38     pointers instead of index addressing in the arrays.
39 
40  Description: Synchronized file with UMTS version 3.2.0. Updated coding
41               template. Removed unncessary include files.
42 
43  Description:  Replaced "int" and/or "char" with OSCL defined types.
44 
45  Who:                           Date:
46  Description:
47 
48 ------------------------------------------------------------------------------
49 */
50 
51 /*----------------------------------------------------------------------------
52 ; INCLUDES
53 ----------------------------------------------------------------------------*/
54 #include    "gmed_n.h"
55 #include    "typedef.h"
56 
57 /*----------------------------------------------------------------------------
58 ; MACROS
59 ; Define module specific macros here
60 ----------------------------------------------------------------------------*/
61 
62 
63 /*----------------------------------------------------------------------------
64 ; DEFINES
65 ; Include all pre-processor statements here. Include conditional
66 ; compile variables also.
67 ----------------------------------------------------------------------------*/
68 #define NMAX    9   /* largest N used in median calculation */
69 
70 /*----------------------------------------------------------------------------
71 ; LOCAL FUNCTION DEFINITIONS
72 ; Function Prototype declaration
73 ----------------------------------------------------------------------------*/
74 
75 
76 /*----------------------------------------------------------------------------
77 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS
78 ; Variable declaration - defined here and used outside this module
79 ----------------------------------------------------------------------------*/
80 
81 
82 /*
83 ------------------------------------------------------------------------------
84  FUNCTION NAME: gmed_n
85 ------------------------------------------------------------------------------
86  INPUT AND OUTPUT DEFINITIONS
87 
88  Inputs:
89     ind = input values (Word16)
90     n = number of inputs to find the median (Word16)
91 
92  Returns:
93     median value.
94 
95  Outputs:
96     None.
97 
98  Global Variables Used:
99     None.
100 
101  Local Variables Needed:
102     None.
103 
104 ------------------------------------------------------------------------------
105  FUNCTION DESCRIPTION
106 
107  This function calculates N-point median of a data set. This routine is only
108  valid for a odd number of gains (n <= NMAX).
109 
110 ------------------------------------------------------------------------------
111  REQUIREMENTS
112 
113  None.
114 
115 ------------------------------------------------------------------------------
116  REFERENCES
117 
118  gmed_n.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
119 
120 ------------------------------------------------------------------------------
121  PSEUDO-CODE
122 
123 Word16 gmed_n (   // o : The median value (0...N-1)
124     Word16 ind[], // i : Past gain values
125     Word16 n      // i : The number of gains; this routine
126                   //     is only valid for a odd number of gains
127                   //     (n <= NMAX)
128 )
129 {
130     Word16 i, j, ix = 0;
131     Word16 max;
132     Word16 medianIndex;
133     Word16 tmp[NMAX];
134     Word16 tmp2[NMAX];
135 
136     for (i = 0; i < n; i++)
137     {
138         tmp2[i] = ind[i];
139     }
140 
141     for (i = 0; i < n; i++)
142     {
143         max = -32767;
144         for (j = 0; j < n; j++)
145         {
146             if (sub (tmp2[j], max) >= 0)
147             {
148                 max = tmp2[j];
149                 ix = j;
150             }
151         }
152         tmp2[ix] = -32768;
153         tmp[i] = ix;
154     }
155 
156     medianIndex=tmp[ shr(n,1) ];  // account for complex addressing
157     return (ind[medianIndex]);
158 }
159 
160 ------------------------------------------------------------------------------
161  RESOURCES USED [optional]
162 
163  When the code is written for a specific target processor the
164  the resources used should be documented below.
165 
166  HEAP MEMORY USED: x bytes
167 
168  STACK MEMORY USED: x bytes
169 
170  CLOCK CYCLES: (cycle count equation for this function) + (variable
171                 used to represent cycle count for each subroutine
172                 called)
173      where: (cycle count variable) = cycle count for [subroutine
174                                      name]
175 
176 ------------------------------------------------------------------------------
177  CAUTION [optional]
178  [State any special notes, constraints or cautions for users of this function]
179 
180 ------------------------------------------------------------------------------
181 */
182 
gmed_n(Word16 ind[],Word16 n)183 Word16 gmed_n(            /* o : the median value    */
184     Word16 ind[],   /* i : input values        */
185     Word16 n        /* i : number of inputs    */
186 )
187 {
188     Word16 i, j, ix = 0;
189     Word16 max;
190     Word16 medianIndex;
191     Word16  tmp[NMAX];
192     Word16  tmp2[NMAX];
193 
194     for (i = 0; i < n; i++)
195     {
196         *(tmp2 + i) = *(ind + i);
197     }
198 
199     for (i = 0; i < n; i++)
200     {
201         max = -32767;
202         for (j = 0; j < n; j++)
203         {
204             if (*(tmp2 + j) >= max)
205             {
206                 max = *(tmp2 + j);
207                 ix = j;
208             }
209         }
210         *(tmp2 + ix) = -32768;
211         *(tmp + i) = ix;
212     }
213 
214     medianIndex = *(tmp + (n >> 1));  /* account for complex addressing */
215 
216     return (*(ind + medianIndex));
217 }
218 
219