Fix phpGH-10648: add check function pointer into mbfl_encoding

Previously, mbstring used the same logic for encoding validation as for
encoding conversion.

However, there are ca

Fix phpGH-10648: add check function pointer into mbfl_encoding

Previously, mbstring used the same logic for encoding validation as for
encoding conversion.

However, there are cases where we want to use different logic for validation
and conversion. For example, if a string ends up with missing input
required by the encoding, or if a character is input that is invalid
as an encoding but can be converted, the conversion should succeed and
the validation should fail.

To achieve this, a function pointer mb_check_fn has been added to
struct mbfl_encoding to implement the logic used for validation.
Also, added implementation of validation logic for UTF-7, UTF7-IMAP,
ISO-2022-JP and JIS.

(The same change has already been made to PHP 8.2 and 8.3; see
6fc8d014df. This commit is backporting the change to PHP 8.1.)

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Make error checks on encoding methods for docomo, kddi, sb consistent

Some places use an if check, which implicitly checks for a non-zero
value, and some places use > 0. The > 0 is the c

Make error checks on encoding methods for docomo, kddi, sb consistent

Some places use an if check, which implicitly checks for a non-zero
value, and some places use > 0. The > 0 is the correct one because at
least some of those functions already use the CK() macro to return -1 on
error. Because -1 != 0 this is wrongly interpreted as a success instead
of a failure.

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In legacy text conversion filters, reset filter state in 'flush' function

Up until now, I believed that mbstring had been designed such
that (legacy) text conversion filter objects shoul

In legacy text conversion filters, reset filter state in 'flush' function

Up until now, I believed that mbstring had been designed such
that (legacy) text conversion filter objects should not be
re-used after the 'flush' function is called to complete a
text conversion operation.

However, it turns out that the implementation of
_php_mb_encoding_handler_ex DID re-use filter objects
after flush. That means that functions which were based on
_php_mb_encoding_handler_ex, including mb_parse_str and
php_mb_post_handler, would break in some cases; state left
over from converting one substring (perhaps a variable name)
would affect the results of converting another substring
(perhaps the value of the same variable), and could cause
extraneous characters to get inserted into the output.

All this code should be deleted soon, but fixing it helps me
to avoid spurious failures when fuzzing the new/old code to
look for differences in behavior.

(This bug fix commit was originally applied to PHP-8.2 when fuzzing
the new mbstring text conversion code to check for differences with
the old code. Later, Kentaro Ohkouchi kindly reported a problem with
mb_encode_mimeheader under PHP 8.1 which was caused by the same issue.
Hence, this commit was backported to PHP-8.1.)

Fixes GH-9683.

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mbstring no longer provides 'long' substitutions for erroneous input bytes

Previously, mbstring had a special mode whereby it would convert
erroneous input byte sequences to output like

mbstring no longer provides 'long' substitutions for erroneous input bytes

Previously, mbstring had a special mode whereby it would convert
erroneous input byte sequences to output like "BAD+XXXX", where "XXXX"
would be the erroneous bytes expressed in hexadecimal. This mode could
be enabled by calling `mb_substitute_character("long")`.

However, accurately reproducing input byte sequences from the cached
state of a conversion filter is often tricky, and this significantly
complicates the implementation. Further, the means used for passing
the erroneous bytes through to where the "BAD+XXXX" text is generated
only allows for up to 3 bytes to be passed, meaning that some erroneous
byte sequences are truncated anyways.

More to the point, a search of publically available PHP code indicates
that nobody is really using this feature anyways.

Incidentally, this feature also provided error output like "JIS+XXXX"
if the input 'should have' represented a JISX 0208 codepoint, but it
decodes to a codepoint which does not exist in the JISX 0208 charset.
Similarly, specific error output was provided for non-existent
JISX 0212 codepoints, and likewise for JISX 0213, CP932, and a few
other charsets. All of that is now consigned to the flames.

However, "long" error markers also include a somewhat more useful
"U+XXXX" marker for Unicode codepoints which were successfully
decoded from the input text, but cannot be represented in the output
encoding. Those are still supported.

With this change, there is no need to use a variety of special values
in the high bits of a wchar to represent different types of error
values. We can (and will) just use a single error value. This will be
equal to -1.

One complicating factor: Text conversion functions return an integer to
indicate whether the conversion operation should be immediately
aborted, and the magic 'abort' marker is -1. Also, almost all of these
functions would return the received byte/codepoint to indicate success.
That doesn't work with the new error value; if an input filter detects
an error and passes -1 to the output filter, and the output filter
returns it back, that would be taken to mean 'abort'.

Therefore, amend all these functions to return 0 for success.

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ISO-2022-JP-KDDI text conversion doesn't swallow PUA codepoints

There was a bit of legacy code here which looks like the original author
of mbstring intended to allow conversion of Unico

ISO-2022-JP-KDDI text conversion doesn't swallow PUA codepoints

There was a bit of legacy code here which looks like the original author
of mbstring intended to allow conversion of Unicode Private Use Area
codepoints to ISO-2022-JP-KDDI. However, that code never worked.
It set the output variable to values which were not matched by any
of the 'if' clauses below, which meant that nothing was actually
emitted to the output. In other words, if one tried to convert Unicode
to ISO-2022-JP-KDDI, and the Unicode string contained PUA codepoints,
they would be quietly 'swallowed' and disappear.

I don't know what ISO-2022-JP-KDDI byte sequences the author wanted
to map those PUA codepoints to, and anyways, this use case is so obscure
that there is little point in worrying about it. However, it is better
to remove the non-functioning code than to leave it in.

This means that if now one tries to convert PUA codepoints to
ISO-2022-JP-KDDI, those codepoints will be treated as erroneous rather
than silently ignored.

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Test behavior of 'long' illegal character markers

After mb_substitute_character("long"), mbstring will respond to
erroneous input by inserting 'long' error markers into the output.
D

Test behavior of 'long' illegal character markers

After mb_substitute_character("long"), mbstring will respond to
erroneous input by inserting 'long' error markers into the output.
Depending on the situation, these error markers will either look like
BAD+XXXX (for general bad input), U+XXXX (when the input is OK, but it
converts to Unicode codepoints which cannot be represented in the
output encoding), or an encoding-specific marker like JISX+XXXX or
W932+XXXX.

We have almost no tests for this feature. Add a bunch of tests to
ensure that all our legacy encoding handlers work in a reasonable
way when 'long' error markers are enabled.

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Fix mbstring support for ISO-2022-JP-KDDI encoding

- Treat it as an error if a multi-byte character or escape sequence is truncated
- When converting other encodings to ISO-2022-JP-KDDI,

Fix mbstring support for ISO-2022-JP-KDDI encoding

- Treat it as an error if a multi-byte character or escape sequence is truncated
- When converting other encodings to ISO-2022-JP-KDDI, don't swallow trailing
hash characters or digits
- Don't allow 'control' characters to appear in the middle of a multi-byte char

Note: I was not able to find any kind of official or even semi-official
specification for this legacy encoding. Therefore, the test suite for
ISO-2022-JP-KDDI is based largely on the behavior of the existing code.

Verifying the correctness of program code in this way is very questionable.
In a sense, all you are proving is that the code "does what it does". However,
the test suite will still expose any unintended _changes_ to behavior.

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Remove useless constant MBFL_ENCTYPE_MBCS

This flag indicated that an encoding was 'multi-byte'; it can use a variable
number of bytes to encode each character. As it turns out, we don't

Remove useless constant MBFL_ENCTYPE_MBCS

This flag indicated that an encoding was 'multi-byte'; it can use a variable
number of bytes to encode each character. As it turns out, we don't actually
need to check this flag anywhere, so it's better to remove it.

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Remove unused macros from mbfilter_cp51932.c, mbfilter_iso2022jp_mobile.c

Don't pass invalid JIS X 0212, JIS X 0213, and Windows-CP932 characters through

Similarly to JIS X 0208, mbstring would pass kuten codes which are not mapped
in the JIS X 0212, JIS X 021

Don't pass invalid JIS X 0212, JIS X 0213, and Windows-CP932 characters through

Similarly to JIS X 0208, mbstring would pass kuten codes which are not mapped
in the JIS X 0212, JIS X 0213, or CP932 character sets through silently when
converting to another Japanese encoding.

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Don't pass invalid JIS X 0208 characters through

Many Japanese encodings, such as JIS7/8, Shift JIS, ISO-2022-JP, EUC-JP, and
so on encode characters from the JIS X 0208 character set. J

Don't pass invalid JIS X 0208 characters through

Many Japanese encodings, such as JIS7/8, Shift JIS, ISO-2022-JP, EUC-JP, and
so on encode characters from the JIS X 0208 character set. JIS X 0208 is based
on the concept of a 94x94 table, with numbered rows and columns. However,
more than a thousand of the cells in that table are empty; JIS X 0208 does not
actually use all 94x94=8,836 possible kuten codes.

mbstring had a dubious feature whereby, if a Japanese string contained one of
these 'unmapped' kuten codes, and it was being converted to another Japanese
encoding which was also based on JIS X 0208, the non-existent character would
be silently passed through, and the unmapped kuten code would be re-encoded
using the normal encoding method of the target text encoding.

Again, this _only_ happened if converting the text with the funky kuten code
to a Japanese encoding. If one tried converting it to Unicode, mbstring would
treat that as an error.

If somebody, somewhere, made their own private extension to JIS X 0208, and
used the regular Japanese encodings like Shift JIS and EUC-JP to encode this
private character set, then this feature might conceivably be useful. But how
likely is that? If someone is using Shift JIS, EUC-JP, ISO-2022-JP, etc. to
encode a funky version of JIS X 0208 with extra characters added, then that
should be treated as a separate text encoding.

The code which flags such characters with MBFL_WCSPLANE_JIS0208 is retained
solely for error reporting in `mbfl_filt_conv_illegal_output`.

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Remove mbstring identify filters

mbstring had an 'identify filter' for almost every supported text encoding
which was used when auto-detecting the most likely encoding for a string.

Remove mbstring identify filters

mbstring had an 'identify filter' for almost every supported text encoding
which was used when auto-detecting the most likely encoding for a string.
It would run over the string and set a 'flag' if it saw anything which
did not appear likely to be the encoding in question.

One problem with this scheme was that encodings which merely appeared
less likely to be the correct one were completely rejected, even if there
was no better candidate. Another problem was that the 'identify filters'
had a huge amount of code duplication with the 'conversion filters'.

Eliminate the identify filters. Instead, when auto-detecting text
encoding, use conversion filters to see whether the input string is valid
in candidate encodings or not. At the same type, watch the type of
codepoints which the string decodes to and mark it as less likely if
non-printable characters (ESC, form feed, bell, etc.) or 'private use
area' codepoints are seen.

Interestingly, one old test case in which JIS text was misidentified
as UTF-8 (and this wrong behavior was enshrined in the test) was 'fixed'
and the JIS string is now auto-detected as JIS.

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Refactor mbfl_ident.c, mbfl_encoding.c, mbfl_memory_device.c, mbfl_string.c

- Make everything less gratuitously verbose
- Don't litter the code with lots of unneeded NULL checks (for thi

Refactor mbfl_ident.c, mbfl_encoding.c, mbfl_memory_device.c, mbfl_string.c

- Make everything less gratuitously verbose
- Don't litter the code with lots of unneeded NULL checks (for things which
will never be NULL)
- Don't return success/failure code from functions which can never fail
- For encoding structs, don't use pointers to pointers to pointers for the
list of alias strings. Pointers to pointers (2 levels of indirection)
is what actually makes sense. This gets rid of some extraneous
dereference operations.

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Remove unneeded function mbfl_filt_ident_common_dtor

This was the default destructor for mbfl_identify_filter structs, but there's nothing
we actually need to do to those structs before

Remove unneeded function mbfl_filt_ident_common_dtor

This was the default destructor for mbfl_identify_filter structs, but there's nothing
we actually need to do to those structs before freeing them.

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Remove unneeded function mbfl_filt_conv_common_dtor

This is a default destructor for mbfl_convert_filter structs. The thing is: there
isn't really anything that needs to be done to those

Remove unneeded function mbfl_filt_conv_common_dtor

This is a default destructor for mbfl_convert_filter structs. The thing is: there
isn't really anything that needs to be done to those structs before freeing them.
The default destructor just zeroed out some fields, but there's no reason why
we should actually do that.

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Comment constants in mbfl_consts.h, remove unused ones

These were unused, and almost certainly will never be used:

- MBFL_ENCTYPE_MWC4BE
- MBFL_ENCTYPE_MWC4LE
- MBFL_ENCTYPE

Comment constants in mbfl_consts.h, remove unused ones

These were unused, and almost certainly will never be used:

- MBFL_ENCTYPE_MWC4BE
- MBFL_ENCTYPE_MWC4LE
- MBFL_ENCTYPE_SHFTCODE
- MBFL_ENCTYPE_ENC_STRM

For the latter two, there were some encodings which were marked with these flags;
but nothing ever _checked_ these particular flags.

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Remove redundant includes from mbstring (and make sure correct config.h is used)

Very interesting... it turns out that when Valgrind support was enabled,
`#include "config.h"` from withi

Remove redundant includes from mbstring (and make sure correct config.h is used)

Very interesting... it turns out that when Valgrind support was enabled,
`#include "config.h"` from within mbstring was actually including the file "config.h"
from Valgrind, and not the one from mbstring!!

This is because -I/usr/include/valgrind was added to the compiler invocation _before_
-Iext/mbstring/libmbfl.

Make sure we actually include the file which was intended.

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Fix [-Wmissing-field-initializers] compiler warning in mbstring

Add missing NULL pointer for mbfl_convert_vtbl struct.

Fix compiler warning

This cast is already done for all other _aliases, but this one has
apparently been missed so far.

Don't short-circuit MBFL_OUTPUTFILTER_ILLEGAL_MODE_NONE

Make sure we always go through mbfl_filt_conv_illegal_output(), so
that the number of illegal characters gets counted.

Store input and output filters in mbfl encodings

For functions like mb_chr() and mb_ord() just looking up the
input/output filter for the encoding dominates the runtime. This
commit

Store input and output filters in mbfl encodings

For functions like mb_chr() and mb_ord() just looking up the
input/output filter for the encoding dominates the runtime. This
commit stores the input/output filter for an encoding in the
mbfl encoding structure, so it can be looked up directly, rather
than scanning through filter function lists.

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Check mbfl_filt_put_invalid_char return value

And fix some libmbfl warnings

trailing whitespace removal

- Fixed possible uninitialized scalar variable usage (spotted by Coverity)

Remove unused variables in libmbfl