118 lines
2.3 KiB
C++
118 lines
2.3 KiB
C++
/*
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* \brief Print to the standard output of the kernel
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* \author Martin stein
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* \date 2012-04-05
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*/
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/*
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* Copyright (C) 2012-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _INCLUDE__KERNEL__LOG_H_
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#define _INCLUDE__KERNEL__LOG_H_
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/* Genode includes */
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#include <kernel/interface.h>
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namespace Kernel
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{
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/**
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* Prints incoming streams to the standard output of the kernel
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*/
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class Log
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{
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private:
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/**
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* Print an unsigned 4 bit integer x as hexadecimal value
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*/
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void _print_4bit_hex(unsigned char x) const
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{
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/* decode to ASCII char */
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x &= 0x0f;
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if (x > 9) x += 39;
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x += 48;
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/* print ASCII char */
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print_char(x);
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}
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public:
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/**
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* Print a zero-terminated string s
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*/
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Log & operator << (char const * s)
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{
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while (*s) print_char(*s++);
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if (*--s != '\n') { print_char(' '); }
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return *this;
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}
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/**
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* Print an unsigned integer x as hexadecimal value
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*/
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Log & operator << (unsigned long const x)
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{
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enum {
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BYTE_WIDTH = 8,
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CW = sizeof(unsigned char)*BYTE_WIDTH,
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IW = sizeof(unsigned int)*BYTE_WIDTH
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};
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/*
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* Walk from most significant to least significant bit and
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* process 2 hex digits per step.
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*/
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bool leading = true;
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for (int i = IW - CW; i >= 0; i = i - CW)
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{
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/* fetch the 2 current digits */
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unsigned char c = (char)((x >> i) & 0xff);
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/* has the payload part of the value already begun? */
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if (leading)
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{
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/* ignore leading zeros ... */
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if (!c)
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{
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/* ... expect they are the only digits */
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if (i == 0) _print_4bit_hex(c);
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continue;
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}
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/* transit from leading to payload part */
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leading = false;
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if (c < 0x10) {
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_print_4bit_hex(c);
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continue;
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}
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}
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/* print both digits */
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_print_4bit_hex(c >> 4);
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_print_4bit_hex(c);
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}
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print_char(' ');
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return *this;
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}
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/**
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* Print a pointer p as hexadecimal value
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*/
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Log & operator << (void * const p) { return *this << (unsigned long)p; }
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};
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/**
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* Return singleton kernel-log
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*/
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inline Log & log()
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{
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static Log s;
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return s;
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}
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}
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#endif /* _INCLUDE__KERNEL__LOG_H_ */
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