# charencode.py - miscellaneous character encoding

#

#  Copyright 2005-2009 Olivia Mackall <olivia@selenic.com> and others

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

import array

from .. import pycompat

def isasciistr(s):

    try:

        s.decode('ascii')

        return True

    except UnicodeDecodeError:

        return False

def asciilower(s):

    """convert a string to lowercase if ASCII

    Raises UnicodeDecodeError if non-ASCII characters are found."""

    s.decode('ascii')

    return s.lower()

def asciiupper(s):

    """convert a string to uppercase if ASCII

    Raises UnicodeDecodeError if non-ASCII characters are found."""

    s.decode('ascii')

    return s.upper()

_jsonmap = []

_jsonmap.extend(b"\\u%04x" % x for x in range(32))

_jsonmap.extend(pycompat.bytechr(x) for x in range(32, 127))

_jsonmap.append(b'\\u007f')

_jsonmap[0x09] = b'\\t'

_jsonmap[0x0A] = b'\\n'

_jsonmap[0x22] = b'\\"'

_jsonmap[0x5C] = b'\\\\'

_jsonmap[0x08] = b'\\b'

_jsonmap[0x0C] = b'\\f'

_jsonmap[0x0D] = b'\\r'

_paranoidjsonmap = _jsonmap[:]

_paranoidjsonmap[0x3C] = b'\\u003c'  # '<' (e.g. escape "</script>")

_paranoidjsonmap[0x3E] = b'\\u003e'  # '>'

_jsonmap.extend(pycompat.bytechr(x) for x in range(128, 256))

def jsonescapeu8fast(u8chars, paranoid):

    """Convert a UTF-8 byte string to JSON-escaped form (fast path)

    Raises ValueError if non-ASCII characters have to be escaped.

    """

    if paranoid:

        jm = _paranoidjsonmap

    else:

        jm = _jsonmap

    try:

        return b''.join(jm[x] for x in bytearray(u8chars))

    except IndexError:

        raise ValueError

_utf8strict = r'surrogatepass'

def jsonescapeu8fallback(u8chars, paranoid):

    """Convert a UTF-8 byte string to JSON-escaped form (slow path)

    Escapes all non-ASCII characters no matter if paranoid is False.

    """

    if paranoid:

        jm = _paranoidjsonmap

    else:

        jm = _jsonmap

    # non-BMP char is represented as UTF-16 surrogate pair

    u16b = u8chars.decode('utf-8', _utf8strict).encode('utf-16', _utf8strict)

    u16codes = array.array('H', u16b)

    u16codes.pop(0)  # drop BOM

    return b''.join(jm[x] if x < 128 else b'\\u%04x' % x for x in u16codes)