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/*++
/* NAME
/* hex_quote 3
/* SUMMARY
/* quote/unquote text, HTTP style.
/* SYNOPSIS
/* #include <hex_quote.h>
/*
/* VSTRING *hex_quote(hex, raw)
/* VSTRING *hex;
/* const char *raw;
/*
/* VSTRING *hex_unquote(raw, hex)
/* VSTRING *raw;
/* const char *hex;
/* DESCRIPTION
/* hex_quote() takes a null-terminated string and replaces non-printable
/* and whitespace characters and the % by %XX, XX being the two-digit
/* hexadecimal equivalent.
/* The hexadecimal codes are produced as upper-case characters. The result
/* value is the hex argument.
/*
/* hex_unquote() performs the opposite transformation. This function
/* understands lowercase, uppercase, and mixed case %XX sequences. The
/* result value is the raw argument in case of success, a null pointer
/* otherwise.
/* BUGS
/* hex_quote() cannot process null characters in data.
/* 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
/*
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/* System library. */
#include "sys_defs.h"
#include <ctype.h>
/* Utility library. */
#include "msg.h"
#include "vstring.h"
#include "hex_quote.h"
/* Application-specific. */
#define STR(x) vstring_str(x)
#define LEN(x) VSTRING_LEN(x)
/* hex_quote - raw data to quoted */
VSTRING *hex_quote(VSTRING *hex, const char *raw)
{
const char *cp;
int ch;
VSTRING_RESET(hex);
for (cp = raw; (ch = *(unsigned const char *) cp) != 0; cp++) {
if (ch != '%' && !ISSPACE(ch) && ISPRINT(ch)) {
VSTRING_ADDCH(hex, ch);
} else {
vstring_sprintf_append(hex, "%%%02X", ch);
}
}
VSTRING_TERMINATE(hex);
return (hex);
}
/* hex_unquote - quoted data to raw */
VSTRING *hex_unquote(VSTRING *raw, const char *hex)
{
const char *cp;
int ch;
VSTRING_RESET(raw);
for (cp = hex; (ch = *cp) != 0; cp++) {
if (ch == '%') {
if (ISDIGIT(cp[1]))
ch = (cp[1] - '0') << 4;
else if (cp[1] >= 'a' && cp[1] <= 'f')
ch = (cp[1] - 'a' + 10) << 4;
else if (cp[1] >= 'A' && cp[1] <= 'F')
ch = (cp[1] - 'A' + 10) << 4;
else
return (0);
if (ISDIGIT(cp[2]))
ch |= (cp[2] - '0');
else if (cp[2] >= 'a' && cp[2] <= 'f')
ch |= (cp[2] - 'a' + 10);
else if (cp[2] >= 'A' && cp[2] <= 'F')
ch |= (cp[2] - 'A' + 10);
else
return (0);
cp += 2;
}
VSTRING_ADDCH(raw, ch);
}
VSTRING_TERMINATE(raw);
return (raw);
}
#ifdef TEST
/*
* Proof-of-concept test program: convert to hex and back.
*/
#include <vstream.h>
#define BUFLEN 1024
static ssize_t read_buf(VSTREAM *fp, VSTRING *buf)
{
ssize_t len;
len = vstream_fread_buf(fp, buf, BUFLEN);
VSTRING_TERMINATE(buf);
return (len);
}
int main(int unused_argc, char **unused_argv)
{
VSTRING *raw = vstring_alloc(BUFLEN);
VSTRING *hex = vstring_alloc(100);
ssize_t len;
while ((len = read_buf(VSTREAM_IN, raw)) > 0) {
hex_quote(hex, STR(raw));
if (hex_unquote(raw, STR(hex)) == 0)
msg_fatal("bad input: %.100s", STR(hex));
if (LEN(raw) != len)
msg_fatal("len %ld != raw len %ld", (long) len, (long) LEN(raw));
if (vstream_fwrite(VSTREAM_OUT, STR(raw), LEN(raw)) != LEN(raw))
msg_fatal("write error: %m");
}
vstream_fflush(VSTREAM_OUT);
vstring_free(raw);
vstring_free(hex);
return (0);
}
#endif
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