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 ----------------------------------------------------------------------------*/ 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
