separate out rot13(1)

This commit is contained in:
2022-09-12 23:28:28 -04:00
parent 7441fa08ea
commit 261f2d46d7
6 changed files with 99 additions and 158 deletions
-41
View File
@@ -1,41 +0,0 @@
#include <ctype.h> /* isalpha(3), isupper(3) */
#include <stdio.h> /* getc(3), putc(3) */
#include <stddef.h> /* stdin, stdout, EOF */
#include <string.h> /* strchr(3), strlen(3) */
#include <sysexits.h> /* EX_OK, EX_USAGE */
#include <unistd.h> /* write(2) */
#include "libio.h" /* fdputs(3) */
#include "usefulmacros.h" /* ARRAYLEN */
static char *program_name = "rot13";
/* Assumes this is a character in the provided glyph system.
* Probably not Unicode-capable but doesn't assume Alphabet.
* Returns `c` rotated around `a` by `r` characters. */
static int
caesar(char c, int r, const char *a){
return a[(strchr(a, c) - a + r) % strlen(a)];
}
/* It's faster to assume Alphabet. */
static char alpha_upper[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLM";
static char alpha_lower[] = "abcdefghijklmnopqrstuvwxyzabcdefghijklm";
int main(int argc, char *argv[]){
char *a;
int c;
if(argc > 1){
write(2, "Usage: ", 7);
fdputs(2, argv[0] == NULL ? program_name : argv[0]);
return EX_USAGE;
}
while((c = getc(stdin)) != EOF){
if(isalpha(c)){
a = isupper(c) ? alpha_upper : alpha_lower;
putc(a[c - a[0] + 13], stdout);
}else
putc(c, stdout);
}
}
-113
View File
@@ -1,113 +0,0 @@
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "arraylen.h"
#include "bool.h"
#define TAGSTART '<'
#define TAGEND '>'
#define ETAG '/'
#define LF '\n'
/*
start-tag end-tag
| |
V V
<TAG>CONTENT</TAG>
^ ^ ^
| | |
| TAGEND ETAG
|
TAGSTART
empty-element tag
|
| optional whitespace
| |
| | TAGEND
| | |
V V V
<TAG />
^ ^
| |
| ETAG
|
TAGSTART
*/
/* a lot of this program's design is weird and kind of overengineered.
this is to drastically limit the memory used. */
enum state{
error = -1, /* for future use */
init = 0, /* waiting for a root tag */
starttagreading,
tagreading,
eetagreading, /* throw away everything until state change */
endtagreading,
contentreading /* printing */
};
void
usage(char *name){
fprintf(stdout, "Usage: %s [tag...]\n", name);
return;
}
int main(int argc, char *argv[]){
if(argc < 2){
usage(argv[0]);
return 0;
}
bool enable = 0;
char c;
int linenumber = 0;
enum state s = init;
FILE *input = stdin;
FILE *output = stdout;
int level = 1; /* 1-indexed because args start at 1 */
size_t p = 0;
while(c = getc(input) != EOF){
if(c == LF){
++linenumber;
continue;
}
switch(s){
case init:
if(c == TAGSTART)
s = starttagreading;
break;
case starttagreading:
if(c == ETAG)
s = endtagreading;
else if(!isblank(c))
s = tagreading;
break;
case tagreading:
if(c == ETAG)
s = eetagreading;
break;
/* case eetagreading: */
case endtagreading:
if(c == ETAG)
fprintf(stderr, "%s:%d: Stray \'%c\' in an end tag?\n", argv[0], linenumber, ETAG);
break;
case contentreading:
if(enable)
putc(c, output);
else if(c == TAGSTART)
s = starttagreading;
else if(c == TAGEND)
fprintf(stderr, "%s:%d: Possible state error or XML syntax error; \'%c\' in mode contentreading\n", argv[0], linenumber, TAGEND);
break;
}
}
return 0;
}