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1 /****************************************************************************
2  * Copyright (C) 2014-2015 Intel Corporation.   All Rights Reserved.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21  * IN THE SOFTWARE.
22  *
23  * @file knobs_init.h
24  *
25  * @brief Dynamic Knobs Initialization for Core.
26  *
27  ******************************************************************************/
28 #pragma once
29 
30 #include <core/knobs.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <ctype.h>
34 #include <stdio.h>
35 
36 // Assume the type is compatible with a 32-bit integer
37 template <typename T>
ConvertEnvToKnob(const char * pOverride,T & knobValue)38 static inline void ConvertEnvToKnob(const char* pOverride, T& knobValue)
39 {
40     uint32_t value    = 0;
41     char*    pStopped = nullptr;
42     value             = strtoul(pOverride, &pStopped, 0);
43     if (pStopped != pOverride)
44     {
45         knobValue = static_cast<T>(value);
46     }
47 }
48 
ConvertEnvToKnob(const char * pOverride,bool & knobValue)49 static inline void ConvertEnvToKnob(const char* pOverride, bool& knobValue)
50 {
51     size_t len = strlen(pOverride);
52     if (len == 1)
53     {
54         auto c = tolower(pOverride[0]);
55         if (c == 'y' || c == 't' || c == '1')
56         {
57             knobValue = true;
58             return;
59         }
60         if (c == 'n' || c == 'f' || c == '0')
61         {
62             knobValue = false;
63             return;
64         }
65     }
66 
67     // Try converting to a number and casting to bool
68     uint32_t value    = 0;
69     char*    pStopped = nullptr;
70     value             = strtoul(pOverride, &pStopped, 0);
71     if (pStopped != pOverride)
72     {
73         knobValue = value != 0;
74     }
75 }
76 
ConvertEnvToKnob(const char * pOverride,float & knobValue)77 static inline void ConvertEnvToKnob(const char* pOverride, float& knobValue)
78 {
79     float value = knobValue;
80     if (sscanf(pOverride, "%f", &value))
81     {
82         knobValue = value;
83     }
84 }
85 
ConvertEnvToKnob(const char * pOverride,std::string & knobValue)86 static inline void ConvertEnvToKnob(const char* pOverride, std::string& knobValue)
87 {
88     knobValue = pOverride;
89 }
90 
91 template <typename T>
InitKnob(T & knob)92 static inline void InitKnob(T& knob)
93 {
94     // Read environment variables
95     const char* pOverride = getenv(knob.Name());
96 
97     if (pOverride)
98     {
99         auto knobValue = knob.DefaultValue();
100         ConvertEnvToKnob(pOverride, knobValue);
101         knob.Value(knobValue);
102     }
103     else
104     {
105         // Set default value
106         knob.Value(knob.DefaultValue());
107     }
108 }
109