netsurf/utils/punycode.h
2014-06-04 13:24:24 +01:00

168 lines
6.4 KiB
C

/*
punycode-sample.c 2.0.0 (2004-Mar-21-Sun)
http://www.nicemice.net/idn/
Adam M. Costello
http://www.nicemice.net/amc/
This is ANSI C code (C89) implementing Punycode 1.0.x.
This single file contains three sections (an interface, an
implementation, and a wrapper for testing) that would normally belong
in three separate files (punycode.h, punycode.c, punycode-test.c), but
here they are bundled into one file (punycode-sample.c) for convenient
testing. Anyone wishing to reuse this code will probably want to split
it apart.
*/
/************************************************************/
/* Public interface (would normally go in its own .h file): */
#include <limits.h>
#include <stddef.h>
enum punycode_status {
punycode_success = 0,
punycode_bad_input = 1, /* Input is invalid. */
punycode_big_output = 2, /* Output would exceed the space provided. */
punycode_overflow = 3 /* Wider integers needed to process input. */
};
/* punycode_uint needs to be unsigned and needs to be */
/* at least 26 bits wide. The particular type can be */
/* specified by defining PUNYCODE_UINT, otherwise a */
/* suitable type will be chosen automatically. */
#ifdef PUNYCODE_UINT
typedef PUNYCODE_UINT punycode_uint;
#elif UINT_MAX >= (1 << 26) - 1
typedef unsigned int punycode_uint;
#else
typedef unsigned long punycode_uint;
#endif
enum punycode_status punycode_encode(
size_t, /* input_length */
const punycode_uint [], /* input */
const unsigned char [], /* case_flags */
size_t *, /* output_length */
char [] /* output */
);
/*
punycode_encode() converts a sequence of code points (presumed to be
Unicode code points) to Punycode.
Input arguments (to be supplied by the caller):
input_length
The number of code points in the input array and the number
of flags in the case_flags array.
input
An array of code points. They are presumed to be Unicode
code points, but that is not strictly necessary. The
array contains code points, not code units. UTF-16 uses
code units D800 through DFFF to refer to code points
10000..10FFFF. The code points D800..DFFF do not occur in
any valid Unicode string. The code points that can occur in
Unicode strings (0..D7FF and E000..10FFFF) are also called
Unicode scalar values.
case_flags
A null pointer or an array of boolean values parallel to
the input array. Nonzero (true, flagged) suggests that the
corresponding Unicode character be forced to uppercase after
being decoded (if possible), and zero (false, unflagged)
suggests that it be forced to lowercase (if possible).
ASCII code points (0..7F) are encoded literally, except that
ASCII letters are forced to uppercase or lowercase according
to the corresponding case flags. If case_flags is a null
pointer then ASCII letters are left as they are, and other
code points are treated as unflagged.
Output arguments (to be filled in by the function):
output
An array of ASCII code points. It is *not* null-terminated;
it will contain zeros if and only if the input contains
zeros. (Of course the caller can leave room for a
terminator and add one if needed.)
Input/output arguments (to be supplied by the caller and overwritten
by the function):
output_length
The caller passes in the maximum number of ASCII code points
that it can receive. On successful return it will contain
the number of ASCII code points actually output.
Return value:
Can be any of the punycode_status values defined above except
punycode_bad_input. If not punycode_success, then output_size
and output might contain garbage.
*/
enum punycode_status punycode_decode(
size_t, /* input_length */
const char [], /* input */
size_t *, /* output_length */
punycode_uint [], /* output */
unsigned char [] /* case_flags */
);
/*
punycode_decode() converts Punycode to a sequence of code points
(presumed to be Unicode code points).
Input arguments (to be supplied by the caller):
input_length
The number of ASCII code points in the input array.
input
An array of ASCII code points (0..7F).
Output arguments (to be filled in by the function):
output
An array of code points like the input argument of
punycode_encode() (see above).
case_flags
A null pointer (if the flags are not needed by the caller)
or an array of boolean values parallel to the output array.
Nonzero (true, flagged) suggests that the corresponding
Unicode character be forced to uppercase by the caller (if
possible), and zero (false, unflagged) suggests that it
be forced to lowercase (if possible). ASCII code points
(0..7F) are output already in the proper case, but their
flags will be set appropriately so that applying the flags
would be harmless.
Input/output arguments (to be supplied by the caller and overwritten
by the function):
output_length
The caller passes in the maximum number of code points
that it can receive into the output array (which is also
the maximum number of flags that it can receive into the
case_flags array, if case_flags is not a null pointer). On
successful return it will contain the number of code points
actually output (which is also the number of flags actually
output, if case_flags is not a null pointer). The decoder
will never need to output more code points than the number
of ASCII code points in the input, because of the way the
encoding is defined. The number of code points output
cannot exceed the maximum possible value of a punycode_uint,
even if the supplied output_length is greater than that.
Return value:
Can be any of the punycode_status values defined above. If not
punycode_success, then output_length, output, and case_flags
might contain garbage.
*/