=pod

=head1 NAME

UI_STRING, UI_string_types, UI_get_string_type,
UI_get_input_flags, UI_get0_output_string,
UI_get0_action_string, UI_get0_result_string, UI_get_result_string_length,
UI_get0_test_string, UI_get_result_minsize,
UI_get_result_maxsize, UI_set_result, UI_set_result_ex
- User interface string parsing

=head1 SYNOPSIS

 #include <openssl/ui.h>

 typedef struct ui_string_st UI_STRING;

 enum UI_string_types {
     UIT_NONE = 0,
     UIT_PROMPT,                 /* Prompt for a string */
     UIT_VERIFY,                 /* Prompt for a string and verify */
     UIT_BOOLEAN,                /* Prompt for a yes/no response */
     UIT_INFO,                   /* Send info to the user */
     UIT_ERROR                   /* Send an error message to the user */
 };

 enum UI_string_types UI_get_string_type(UI_STRING *uis);
 int UI_get_input_flags(UI_STRING *uis);
 const char *UI_get0_output_string(UI_STRING *uis);
 const char *UI_get0_action_string(UI_STRING *uis);
 const char *UI_get0_result_string(UI_STRING *uis);
 int UI_get_result_string_length(UI_STRING *uis);
 const char *UI_get0_test_string(UI_STRING *uis);
 int UI_get_result_minsize(UI_STRING *uis);
 int UI_get_result_maxsize(UI_STRING *uis);
 int UI_set_result(UI *ui, UI_STRING *uis, const char *result);
 int UI_set_result_ex(UI *ui, UI_STRING *uis, const char *result, int len);

=head1 DESCRIPTION

The B<UI_STRING> gets created internally and added to a B<UI> whenever
one of the functions UI_add_input_string(), UI_dup_input_string(),
UI_add_verify_string(), UI_dup_verify_string(),
UI_add_input_boolean(), UI_dup_input_boolean(), UI_add_info_string(),
UI_dup_info_string(), UI_add_error_string() or UI_dup_error_string()
is called.
For a B<UI_METHOD> user, there's no need to know more.
For a B<UI_METHOD> creator, it is of interest to fetch text from these
B<UI_STRING> objects as well as adding results to some of them.

UI_get_string_type() is used to retrieve the type of the given
B<UI_STRING>.

UI_get_input_flags() is used to retrieve the flags associated with the
given B<UI_STRING>.

UI_get0_output_string() is used to retrieve the actual string to
output (prompt, info, error, ...).

UI_get0_action_string() is used to retrieve the action description
associated with a B<UIT_BOOLEAN> type B<UI_STRING>.
For all other B<UI_STRING> types, NULL is returned.
See L<UI_add_input_boolean(3)>.

UI_get0_result_string() and UI_get_result_string_length() are used to
retrieve the result of a prompt and its length.
This is only useful for B<UIT_PROMPT> and B<UIT_VERIFY> type strings.
For all other B<UI_STRING> types, UI_get0_result_string() returns NULL
and UI_get_result_string_length() returns -1.

UI_get0_test_string() is used to retrieve the string to compare the
prompt result with.
This is only useful for B<UIT_VERIFY> type strings.
For all other B<UI_STRING> types, NULL is returned.

UI_get_result_minsize() and UI_get_result_maxsize() are used to
retrieve the minimum and maximum required size of the result.
This is only useful for B<UIT_PROMPT> and B<UIT_VERIFY> type strings.
For all other B<UI_STRING> types, -1 is returned.

UI_set_result_ex() is used to set the result value of a prompt and its length.
For B<UIT_PROMPT> and B<UIT_VERIFY> type UI strings, this sets the
result retrievable with UI_get0_result_string() by copying the
contents of B<result> if its length fits the minimum and maximum size
requirements.
For B<UIT_BOOLEAN> type UI strings, this sets the first character of
the result retrievable with UI_get0_result_string() to the first
B<ok_char> given with UI_add_input_boolean() or UI_dup_input_boolean()
if the B<result> matched any of them, or the first of the
B<cancel_chars> if the B<result> matched any of them, otherwise it's
set to the NUL char C<\0>.
See L<UI_add_input_boolean(3)> for more information on B<ok_chars> and
B<cancel_chars>.

UI_set_result() does the same thing as UI_set_result_ex(), but calculates
its length internally.
It expects the string to be terminated with a NUL byte, and is therefore
only useful with normal C strings.

=head1 RETURN VALUES

UI_get_string_type() returns the UI string type.

UI_get_input_flags() returns the UI string flags.

UI_get0_output_string() returns the UI string output string.

UI_get0_action_string() returns the UI string action description
string for B<UIT_BOOLEAN> type UI strings, NULL for any other type.

UI_get0_result_string() returns the UI string result buffer for
B<UIT_PROMPT> and B<UIT_VERIFY> type UI strings, NULL for any other
type.

UI_get_result_string_length() returns the UI string result buffer's
content length for B<UIT_PROMPT> and B<UIT_VERIFY> type UI strings,
-1 for any other type.

UI_get0_test_string() returns the UI string action description
string for B<UIT_VERIFY> type UI strings, NULL for any other type.

UI_get_result_minsize() returns the minimum allowed result size for
the UI string for B<UIT_PROMPT> and B<UIT_VERIFY> type strings,
-1 for any other type.

UI_get_result_maxsize() returns the minimum allowed result size for
the UI string for B<UIT_PROMPT> and B<UIT_VERIFY> type strings,
-1 for any other type.

UI_set_result() returns 0 on success or when the UI string is of any
type other than B<UIT_PROMPT>, B<UIT_VERIFY> or B<UIT_BOOLEAN>, -1 on
error.

=head1 SEE ALSO

L<UI(3)>

=head1 COPYRIGHT

Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut