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/*++
/* NAME
/* unescape 3
/* SUMMARY
/* translate C-like escape sequences
/* SYNOPSIS
/* #include <stringops.h>
/*
/* VSTRING *unescape(result, input)
/* VSTRING *result;
/* const char *input;
/*
/* VSTRING *escape(result, input, len)
/* VSTRING *result;
/* const char *input;
/* ssize_t len;
/* DESCRIPTION
/* unescape() translates C-like escape sequences in the null-terminated
/* string \fIinput\fR and places the result in \fIresult\fR. The result
/* is null-terminated, and is the function result value.
/*
/* escape() does the reverse transformation.
/*
/* Escape sequences and their translations:
/* .IP \ea
/* Bell character.
/* .IP \eb
/* Backspace character.
/* .IP \ef
/* formfeed character.
/* .IP \en
/* newline character
/* .IP \er
/* Carriage-return character.
/* .IP \et
/* Horizontal tab character.
/* .IP \ev
/* Vertical tab character.
/* .IP \e\e
/* Backslash character.
/* .IP \e\fInum\fR
/* 8-bit character whose ASCII value is the 1..3 digit
/* octal number \fInum\fR.
/* .IP \e\fIother\fR
/* The backslash character is discarded.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <ctype.h>
/* Utility library. */
#include <vstring.h>
#include <stringops.h>
/* unescape - process escape sequences */
VSTRING *unescape(VSTRING *result, const char *data)
{
int ch;
int oval;
int i;
#define UCHAR(cp) ((unsigned char *) (cp))
#define ISOCTAL(ch) (ISDIGIT(ch) && (ch) != '8' && (ch) != '9')
VSTRING_RESET(result);
while ((ch = *UCHAR(data++)) != 0) {
if (ch == '\\') {
if ((ch = *UCHAR(data++)) == 0)
break;
switch (ch) {
case 'a': /* \a -> audible bell */
ch = '\a';
break;
case 'b': /* \b -> backspace */
ch = '\b';
break;
case 'f': /* \f -> formfeed */
ch = '\f';
break;
case 'n': /* \n -> newline */
ch = '\n';
break;
case 'r': /* \r -> carriagereturn */
ch = '\r';
break;
case 't': /* \t -> horizontal tab */
ch = '\t';
break;
case 'v': /* \v -> vertical tab */
ch = '\v';
break;
case '0': /* \nnn -> ASCII value */
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
for (oval = ch - '0', i = 0;
i < 2 && (ch = *UCHAR(data)) != 0 && ISOCTAL(ch);
i++, data++) {
oval = (oval << 3) | (ch - '0');
}
ch = oval;
break;
default: /* \any -> any */
break;
}
}
VSTRING_ADDCH(result, ch);
}
VSTRING_TERMINATE(result);
return (result);
}
/* escape - reverse transformation */
VSTRING *escape(VSTRING *result, const char *data, ssize_t len)
{
int ch;
VSTRING_RESET(result);
while (len-- > 0) {
ch = *UCHAR(data++);
if (ISASCII(ch)) {
if (ISPRINT(ch)) {
if (ch == '\\')
VSTRING_ADDCH(result, ch);
VSTRING_ADDCH(result, ch);
continue;
} else if (ch == '\a') { /* \a -> audible bell */
vstring_strcat(result, "\\a");
continue;
} else if (ch == '\b') { /* \b -> backspace */
vstring_strcat(result, "\\b");
continue;
} else if (ch == '\f') { /* \f -> formfeed */
vstring_strcat(result, "\\f");
continue;
} else if (ch == '\n') { /* \n -> newline */
vstring_strcat(result, "\\n");
continue;
} else if (ch == '\r') { /* \r -> carriagereturn */
vstring_strcat(result, "\\r");
continue;
} else if (ch == '\t') { /* \t -> horizontal tab */
vstring_strcat(result, "\\t");
continue;
} else if (ch == '\v') { /* \v -> vertical tab */
vstring_strcat(result, "\\v");
continue;
}
}
vstring_sprintf_append(result, "\\%03o", ch);
}
VSTRING_TERMINATE(result);
return (result);
}
#ifdef TEST
#include <stdlib.h>
#include <string.h>
#include <msg.h>
#include <vstring_vstream.h>
int main(int argc, char **argv)
{
VSTRING *in = vstring_alloc(10);
VSTRING *out = vstring_alloc(10);
int un_escape = 1;
if (argc > 2 || (argc > 1 && (un_escape = strcmp(argv[1], "-e"))) != 0)
msg_fatal("usage: %s [-e (escape)]", argv[0]);
if (un_escape) {
while (vstring_fgets_nonl(in, VSTREAM_IN)) {
unescape(out, vstring_str(in));
vstream_fwrite(VSTREAM_OUT, vstring_str(out), VSTRING_LEN(out));
VSTREAM_PUTC('\n', VSTREAM_OUT);
}
} else {
while (vstring_fgets_nonl(in, VSTREAM_IN)) {
escape(out, vstring_str(in), VSTRING_LEN(in));
vstream_fwrite(VSTREAM_OUT, vstring_str(out), VSTRING_LEN(out));
VSTREAM_PUTC('\n', VSTREAM_OUT);
}
}
vstream_fflush(VSTREAM_OUT);
exit(0);
}
#endif
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