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C02/doc/ctype.txt
2018-01-28 14:00:23 -05:00

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Character Checking and Conversion Functions for C02
This library provides functions for classifying ASCII characters, as
well as converting upper-case characters to lower-case characters
and vice-versa.
The character classification functions return a value of -1 ($FF)
for TRUE, and 0 for FALSE. All these functions return FALSE when
passed a high ASCII character (127 - 255).
#include <ctype.h02>
The following functions are defined:
b = isalnm(c); Returns TRUE if c is alphanumeric, otherwise FALSE.
An alphanumeric character is a letter (A-Z or a-z),
or a digit (0-9).
Note: Calls internal routine isaln, which in turn
calls internal routines isdgt and isalp.
b = isalph(c); Returns TRUE if c is alphabetic, otherwise FALSE.
An alphabetic character is a letter (A-Z or a-z).
Note: Call internal routine isalp, which in turn
calls internal routines isupr and islwr.
b = isbdgt(c); Returns TRUE if c is a binary digit, otherwise FALSE.
A binary digit is a character in the range 0 through 1.
Note: Calls internal routine isbin, which shares code
with the internal routine isdgt.
b = isctrl(c); Returns TRUE if c is a control characte, otherwise FALSE.
A control character is a character with ASCII code
0 through 31 or 127.
Note: Calls internal routine isctl.
b = isdigt(c); Returns TRUE if c is a digit, otherwise FALSE.
A digit is a character in the range 0 through 9.
Note: Calls internal routine isdgt.
b = isgrph(c); Returns TRUE if c is graphical, otherwise FALSE.
A graphical character is any character in the
range ! through |.
Note: Calls internal routine isgrp, which in turn
calls internal routine isprt.
b = ishdgt(c); Returns TRUE if c is a hex digit, otherwise FALSE.
A hex digit is a character in the range 0 through 9.
A through F, or a through f.
Note: Calls internal routine ishex, which in turn
calls internal routine isdgt.
b = islowr(c); Returns TRUE if c is lowercase, otherwise FALSE.
An alphabetic character is a letter in the range
a through z.
Note: Call internal routine islwr.
b = ispnct(c); Returns TRUE if c is punctuation, otherwise FALSE.
A punctuation character is any graphical character
that is not aplhapnumeric.
Note: Calls internal routine ispnc, which in turn
calls internal routines isalp and isgrp.
b = isprnt(c); Returns TRUE if c is printable, otherwise FALSE.
A printable character is any character in the
range Space through |.
Note: Calls internal routine isprt.
b = isspce(c); Returns TRUE if c is white space, otherwise FALSE.
The white space characters are Tab (9), Line Feed (10),
Vertical Tab (11), Form Feed (12), Carriage Return (13),
and Space (32).
Note: Calls internal routine isspc.
b = isuppr(c); Returns TRUE if c is upper case, otherwise FALSE.
An uppercase character is a letter in the range
A through Z.
Note: Call internal routine isupr.
t = tolowr(c); Returns lower case version of c if it is an upper case
character, otherwise c.
Note: Calls internal routine isupr.
t = touppr(c); Returns upper case version of c if it is a lower case
character, otherwise c.
Note: Calls internal routine islwr.
Note: This library has no external dependencies.
Implementation: The standard method of implementing the ctype library is to
use a bit mask table of 128 bytes (one for each standard ASCII character).
This library instead uses a series of comparisons in the internal routines,
which leave the accumulator unmodified, and occupies approximately 128 bytes
of memory.