christoph/lecture-operating-system-development
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implement fixed width printing

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This commit is contained in:
churl
2022-04-24 22:27:48 +02:00
parent 832a5cef49
commit d93ee3a49f
4 changed files with 108 additions and 18 deletions
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6
c_os/devices/CGA_Stream.h
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@ -19,15 +19,15 @@
#include "lib/OutStream.h"
class CGA_Stream : public OutStream, public CGA {
private:
CGA_Stream(CGA_Stream &copy); // Verhindere Kopieren
CGA_Stream(CGA_Stream &copy); // Verhindere Kopieren
public:
CGA_Stream () : OutStream(), CGA() { flush(); }
// Methode zur Ausgabe des Pufferinhalts der Basisklasse StringBuffer.
virtual void flush ();
void flush () override;
};
#endif

68
c_os/lib/OutStream.cc
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@ -22,15 +22,64 @@
#include "lib/OutStream.h"
// NOTE: I added this, stream manipulators with arg
OutStream& OutStream::operator << (const fillw& w) {
this->fill_width = w.w;
return *this;
}
OutStream& OutStream::operator << (const fillc& c) {
this->fill_char = c.c;
return *this;
}
// NOTE: I added this, fixed width printing
void OutStream::put(char c) {
if (this->fill_width == 0) {
StringBuffer::put(c);
} else if (this->fill_used == this->fill_width - 1) {
// This indicates that content has been cut
StringBuffer::put('@');
this->fill_use_char();
} else if (this->fill_used == this->fill_width) {
// do nothing
} else {
StringBuffer::put(c);
this->fill_use_char();
}
}
void OutStream::fill_finalize() {
if (this->fill_width == 0 || this->fill_used == this->fill_width) {
// do nothing
} else if (this->fill_used > this->fill_width) {
// should never happen
} else {
for (unsigned char i = 0; i < this->fill_width - this->fill_used; ++i) {
StringBuffer::put(this->fill_char);
}
}
this->fill_used = 0;
}
void OutStream::fill_use_char() {
if (this->fill_width == 0) {
return;
}
this->fill_used++;
}
//
// Zeichen und Zeichenketten in Stream ausgeben
//
OutStream& OutStream::operator << (char c) {
put(c);
if (c != '\n') {
// endl() doesn't has access to StringBuffer::put(), so ignore \n here
this->fill_finalize(); // NOTE: I added this
}
return *this;
}
// TODO: shouldn't this be printed as number?
OutStream& OutStream::operator << (unsigned char c) {
return *this << (char) c;
}
@ -41,6 +90,7 @@ OutStream& OutStream::operator << (char* string) {
put (*pos);
pos++;
}
this->fill_finalize(); // NOTE: I added this
return *this;
}
@ -79,10 +129,10 @@ OutStream& OutStream::operator << (long ival) {
OutStream& OutStream::operator << (unsigned long ival) {
unsigned long div;
char digit;
if (base == 8)
if (base == 8) {
put ('0'); // oktale Zahlen erhalten eine fuehrende Null
else if (base == 16) {
} else if (base == 16) {
put ('0'); // hexadezimale Zahlen ein "0x"
put ('x');
}
@ -94,12 +144,14 @@ OutStream& OutStream::operator << (unsigned long ival) {
// ziffernweise Ausgabe der Zahl
for (; div > 0; div /= (unsigned long) base) {
digit = ival / div;
if (digit < 10)
put ('0' + digit);
else
put ('a' + digit - 10);
if (digit < 10) {
put ('0' + digit);
} else {
put ('a' + digit - 10);
}
ival %= div;
}
this->fill_finalize(); // NOTE: I added this
return *this;
}
@ -130,7 +182,7 @@ OutStream& OutStream::operator << (OutStream& (*f) (OutStream&)) {
// Fuege einen Zeilenumbruch in die Ausgabe ein.
OutStream& endl (OutStream& os) {
os << '\n';
os.flush ();
os.flush();
return os;
}

49
c_os/lib/OutStream.h
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@ -7,13 +7,13 @@
* << Operators fuer die wichtigsten der vordefinierten *
* Datentypen und realisiert somit die bekannte Ausgabe- *
* funktion der C++ iO_Stream Bibliothek. Zur Zeit wird *
* die Darstellung von Zeichen, Zeichenketten und ganzen *
* die Darstellung von Zeichen, Zeichenketten und ganzen *
* Zahlen unterstuetzt. Ein weiterer << Operator erlaubt *
* die Verwendung von Manipulatoren. *
* *
* Neben der Klasse OutStream sind hier auch die *
* Manipulatoren hex, dec, oct und bin fuer die Wahl der *
* Basis bei der Zahlendarstellung, sowie endl fuer den *
* Basis bei der Zahlendarstellung, sowie endl fuer den *
* Zeilenumbruch definiert. *
* *
* Autor: Olaf Spinczyk, TU Dortmund *
@ -24,17 +24,51 @@
#include "lib/StringBuffer.h"
// NOTE: I added this, stream manipulator with argument
class OutStream;
// TODO: Should this only work for the next << ?
class fillw {
public:
fillw(unsigned char w) : w(w) {};
unsigned char w;
};
class fillc {
public:
fillc(char c) : c(c) {};
char c;
};
class OutStream : public StringBuffer {
private:
OutStream(const OutStream &copy); // Verhindere Kopieren
// NOTE: I added this
unsigned char fill_used; // indicates how many characters are already used by the text internally
void fill_use_char(); // recognizes that one char from the print width has been used up
void fill_finalize(); // does the filling after text has been written to buffer
public:
int base; // Basis des Zahlensystems: z.B. 2, 8, 10 oder 16
OutStream () : StringBuffer () { base = 10; } // initial Dezimalsystem
// NOTE: I added this
unsigned char fill_width;
char fill_char; // fill character for fixed width
virtual void flush () = 0; // weiterhin undefiniert
OutStream () : StringBuffer () {
base = 10; // initial Dezimalsystem
fill_width = 0; // no fixed width
fill_used = 0;
fill_char = ' '; // fill with spaces
}
void flush() override = 0; // weiterhin undefiniert aber public
// NOTE: I added this
void put(char c) override;
// OPERATOR << : Umwandlung des angegebenen Datentypes in eine
// Zeichenkette.
@ -57,9 +91,12 @@ public:
// Darstellung eines Zeigers als hexadezimale ganze Zahl
OutStream& operator << (void* ptr);
// NOTE: I added this, set fixed output width
OutStream &operator << (const fillw &w);
OutStream &operator << (const fillc &c);
// Aufruf einer Manipulatorfunktion
OutStream& operator << (OutStream& (*f) (OutStream&));
};

3
c_os/lib/StringBuffer.h
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@ -36,8 +36,9 @@ protected:
// StringBuffer: Im Konstruktor wird der Puffer als leer markiert.
StringBuffer () : pos(0) {}
// NOTE: I changed this
// Fuegt ein Zeichen in den Puffer ein. Wenn der Puffer
void put (char c);
virtual void put (char c);
// Methode zur Ausgabe des Pufferinhalts
virtual void flush () = 0;