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 ------------------------------------------------------------------------------
20 INPUT AND OUTPUT DEFINITIONS
21
22 Inputs:
23 input_ptr = pointer to the buffer containing values of type UChar
24 in a 2D block of data.
25 min_ptr = pointer to the minimum value of type Int to be found in a
26 square block of size BLKSIZE contained in 2D block of data.
27 max_ptr = pointer to the maximum value of type Int to be found in a
28 square block of size BLKSIZE contained in 2D block of data.
29 incr = value of type Int representing the width of 2D block of data.
30
31 Local Stores/Buffers/Pointers Needed:
32 None
33
34 Global Stores/Buffers/Pointers Needed:
35 None
36
37 Outputs:
38 None
39
40 Pointers and Buffers Modified:
41 min_ptr points to the found minimum value in the square block of
42 size BLKSIZE contained in 2D block of data.
43
44 max_ptr points to the found maximum value in the square block of
45 size BLKSIZE contained in 2D block of data.
46
47 Local Stores Modified:
48 None
49
50 Global Stores Modified:
51 None
52
53 ------------------------------------------------------------------------------
54 FUNCTION DESCRIPTION
55
56 This function finds the maximum and the minimum values in a square block of
57 data of size BLKSIZE * BLKSIZE. The data is contained in the buffer which
58 represents a 2D block of data that is larger than BLKSIZE * BLKSIZE.
59 This is illustrated below.
60
61 mem loc x + 00h -> o o o o o o o o o o o o o o o o
62 mem loc x + 10h -> o o o o o X X X X X X X X o o o
63 mem loc x + 20h -> o o o o o X X X X X X X X o o o
64 mem loc x + 30h -> o o o o o X X X X X X X X o o o
65 mem loc x + 40h -> o o o o o X X X X X X X X o o o
66 mem loc x + 50h -> o o o o o X X X X X X X X o o o
67 mem loc x + 60h -> o o o o o X X X X X X X X o o o
68 mem loc x + 70h -> o o o o o X X X X X X X X o o o
69 mem loc x + 80h -> o o o o o X X X X X X X X o o o
70 mem loc x + 90h -> o o o o o o o o o o o o o o o o
71 mem loc x + A0h -> o o o o o o o o o o o o o o o o
72 mem loc x + B0h -> o o o o o o o o o o o o o o o o
73
74 For illustration purposes, the diagram assumes that BLKSIZE is equal to 8
75 but this is not a requirement. In this diagram, the buffer starts at
76 location x but the input pointer, input_ptr, passed into this function
77 would be the first row of data to be searched which is at x + 15h. The
78 value of incr passed onto this function represents the amount the input_ptr
79 needs to be incremented to point to the next row of data.
80
81 This function compares each value in a row to the current maximum and
82 minimum. After each row, input_ptr is incremented to point to the next row.
83 This is repeated until all rows have been processed. When the search is
84 complete the location pointed to by min_ptr contains the minimum value
85 found and the location pointed to by max_ptr contains the maximum value found.
86
87 ------------------------------------------------------------------------------
88 */
89
90
91 /*----------------------------------------------------------------------------
92 ; INCLUDES
93 ----------------------------------------------------------------------------*/
94 #include "mp4dec_lib.h"
95 #include "post_proc.h"
96
97 /*----------------------------------------------------------------------------
98 ; MACROS
99 ; Define module specific macros here
100 ----------------------------------------------------------------------------*/
101
102 /*----------------------------------------------------------------------------
103 ; DEFINES
104 ; Include all pre-processor statements here. Include conditional
105 ; compile variables also.
106 ----------------------------------------------------------------------------*/
107
108 /*----------------------------------------------------------------------------
109 ; LOCAL FUNCTION DEFINITIONS
110 ; Function Prototype declaration
111 ----------------------------------------------------------------------------*/
112
113 /*----------------------------------------------------------------------------
114 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS
115 ; Variable declaration - defined here and used outside this module
116 ----------------------------------------------------------------------------*/
117
118 /*----------------------------------------------------------------------------
119 ; EXTERNAL FUNCTION REFERENCES
120 ; Declare functions defined elsewhere and referenced in this module
121 ----------------------------------------------------------------------------*/
122
123 /*----------------------------------------------------------------------------
124 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
125 ; Declare variables used in this module but defined elsewhere
126 ----------------------------------------------------------------------------*/
127
128 #ifdef PV_POSTPROC_ON
129 /*----------------------------------------------------------------------------
130 ; FUNCTION CODE
131 ----------------------------------------------------------------------------*/
FindMaxMin(uint8 * input_ptr,int * min_ptr,int * max_ptr,int incr)132 void FindMaxMin(
133 uint8 *input_ptr,
134 int *min_ptr,
135 int *max_ptr,
136 int incr)
137 {
138 /*----------------------------------------------------------------------------
139 ; Define all local variables
140 ----------------------------------------------------------------------------*/
141 register uint i, j;
142 register int min, max;
143
144 /*----------------------------------------------------------------------------
145 ; Function body here
146 ----------------------------------------------------------------------------*/
147 max = min = *input_ptr;
148 /* incr = incr - BLKSIZE; */ /* 09/06/2001, already passed in as width - BLKSIZE */
149
150 for (i = BLKSIZE; i > 0; i--)
151 {
152 for (j = BLKSIZE; j > 0; j--)
153 {
154 if (*input_ptr > max)
155 {
156 max = *input_ptr;
157 }
158 else if (*input_ptr < min)
159 {
160 min = *input_ptr;
161 }
162 input_ptr += 1;
163 }
164
165 /* set pointer to the beginning of the next row*/
166 input_ptr += incr;
167 }
168
169 *max_ptr = max;
170 *min_ptr = min;
171 /*----------------------------------------------------------------------------
172 ; Return nothing or data or data pointer
173 ----------------------------------------------------------------------------*/
174 return;
175 }
176 #endif
177