27 lines
596 B
C
27 lines
596 B
C
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#include <ctype.h>
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#include <unctrl.h>
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char *
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unctrl(register unsigned char uch)
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{
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static char buffer[3] = "^x";
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if (isgraph(uch)) {
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/*
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* Printable character. Simply return the character as a one-character
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* string.
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*/
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buffer[1] = uch;
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return &buffer[1];
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}
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uch &= ~0x80;
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/*
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* It is a control character. DEL is handled specially (^?). All others
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* use ^x notation, where x is the character code for the control character
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* with 0x40 ORed in. (Control-A becomes ^A etc.).
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*/ buffer[1] = (uch == 0x7F ? '?' : (uch | 0x40));
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return buffer;
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}
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