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-rw-r--r--src/util/hex_quote.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/src/util/hex_quote.c b/src/util/hex_quote.c
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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