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&optional filenames ¶This function changes the external format used for
*standard-input*, *standard-output*, and
*standard-error* to the external format specified by
terminal. Additionally, the Unix file name encoding can be
set to the value specified by filenames if non-nil.
list all of the vailable external formats. A list is returned where each element is a list of the external format name and a list of aliases for the format. No distinction is made between external formats and composing external formats.
Print a description of the given external-format. This may cause the external format to be loaded (silently) if it is not already loaded.
Since strings are UTF-16 and hence may contain surrogate pairs, some utility functions are provided to make access easier.
&optional end ¶Return the codepoint value from string at position i.
If code unit at that position is a surrogate value, it is combined
with either the previous or following code unit (when possible) to
compute the codepoint. The first return value is the codepoint
itself. The second return value is nil if the position is not a
surrogate pair. Otherwise, +1 or -1 is returned if the position
is the high (leading) or low (trailing) surrogate value, respectively.
This is useful for iterating through a string in codepoint sequence.
Convert the given hi and lo surrogate characters to the corresponding codepoint value
Convert the given codepoint value to the corresponding high
and low surrogate characters. If the codepoint is less than 65536,
the second value is nil since the codepoint does not need to be
represented as a surrogate pair.
&body body ¶with-string-codepoint-iterator
provides a method of looping through a string from the beginning to
the end of the string prodcucing successive codepoints from the
string. next is bound to a generator macro that, within the scope
of the invocation, returns one or two values. The first value tells
whether any objects remain in the string. When the first value is
non-NIL, the second value is the codepoint of the next object.
&body body ¶with-string-glyph-iterator
provides a method of looping through a string from the beginning to
the end of the string prodcucing successive glyphs from the string.
next is bound to a generator macro that, within the scope of the
invocation, returns one or three values. The first value tells
whether any objects remain in the string. When the first value is
non-NIL, the second value is the index into the string of the glyph
and the third value is index of the next glyph.
&optional (start 0) end ¶string-encode encodes string using the format
external-format, producing an array of octets. Each octet is
converted to a character via code-char and the resulting
string is returned.
The optional argument start, defaulting to 0, specifies the starting index and end, defaulting to the length of the string, is the end of the string.
&optional (start 0) end ¶string-decode decodes string using the format
external-format and produces a new string. Each character of
string is converted to octet (by char-code) and the
resulting array of octets is used by the external format to produce
a string. This is the inverse of string-encode.
The optional argument start, defaulting to 0, specifies the starting index and end, defaulting to the length of the string, is the end of the string.
string must consist of characters whose char-code is
less than 256.
:start :end :external-format :buffer :buffer-start :error ¶string-to-octets converts string to a sequence of
octets according to the external format specified by
external-format. The string to be converted is bounded by
start, which defaults to 0, and end, which defaults to
the length of the string. If buffer is specified, the octets
are placed in buffer. If buffer is not specified, a new
array is allocated to hold the octets. buffer-start specifies
where in the buffer the first octet will be placed.
An error method may also be specified by error. Any errors
encountered while converting the string to octets will be handled
according to error. If nil, a replacement character is converted
to octets in place of the error. Otherwise, error should be a
symbol or function that will be called when the error occurs. The
function takes two arguments: an error string and the character
that caused the error. It should return a replacement character.
Three values are returned: The buffer, the number of valid octets written, and the number of characters converted. Note that the actual number of octets written may be greater than the returned value, These represent the partial octets of the next character to be converted, but there was not enough room to hold the complete set of octets.
:start :end :external-format :string :s-start :s-end :state ¶octets-to-string converts the sequence of octets in
octets to a string. octets must be a
(simple-array (unsigned-byte 8) (*)). The octets to be
converted are bounded by start and end, which default to
0 and the length of the array, respectively. The conversion is
performed according to the external format specified by
external-format. If string is specified, the octets are
converted and stored in string, starting at s-start
(defaulting to 0) and ending just before s-end (defaulting to
the end of string. string must be simple-string.
If the bounded string is not large enough to hold all of the
characters, then some octets will not be converted. If string
is not specified, a new string is created.
The state is used as the initial state of for the external format. This is useful when converting buffers of octets where the buffers are not on character boundaries, and state information is needed between buffers.
Four values are returned: the string, the number of characters written to the string, and the number of octets consumed to produce the characters, and the final state of external format after converting the octets.
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