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Fix ASCII-only conversion logic (bug#40407)

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To sidestep conversion altogether when EOL conversion applies, we must
either be encoding a string without NL, or decoding without CR.

* src/coding.c (string_ascii_p): Revert to a pure predicate.
(code_convert_string): Fix logic.  Don't use uninitialised
ascii_p (removed).  Use memchr to detect CR or LF in string when needed.
* test/src/coding-tests.el (coding-nocopy-ascii):
Update tests to include encodings with explicit EOL conversions.
This commit is contained in:
Mattias Engdegård 2020-04-09 12:04:22 +02:00
parent 95dd8de1df
commit d3e2c88041
2 changed files with 38 additions and 41 deletions
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46
src/coding.c
View file

@ -9474,22 +9474,15 @@ not fully specified.) */)
return code_convert_region (start, end, coding_system, destination, 1, 0);
}
/* Non-zero if STR contains only characters in the 0..127 range.
Positive if STR includes characters that don't need EOL conversion
on decoding, negative otherwise. */
static int
string_ascii_p (Lisp_Object str)
/* Whether STRING only contains chars in the 0..127 range. */
static bool
string_ascii_p (Lisp_Object string)
{
ptrdiff_t nbytes = SBYTES (str);
bool CR_Seen = false;
ptrdiff_t nbytes = SBYTES (string);
for (ptrdiff_t i = 0; i < nbytes; i++)
{
if (SREF (str, i) > 127)
return 0;
if (SREF (str, i) == '\r')
CR_Seen = true;
}
return CR_Seen ? -1 : 1;
if (SREF (string, i) > 127)
return false;
return true;
}
Lisp_Object
@ -9526,24 +9519,19 @@ code_convert_string (Lisp_Object string, Lisp_Object coding_system,
if (EQ (dst_object, Qt))
{
/* Fast path for ASCII-only input and an ASCII-compatible coding:
act as identity if no EOL conversion is neede. */
int ascii_p;
act as identity if no EOL conversion is needed. */
Lisp_Object attrs = CODING_ID_ATTRS (coding.id);
if (! NILP (CODING_ATTR_ASCII_COMPAT (attrs))
&& (STRING_MULTIBYTE (string)
? (chars == bytes) : ((ascii_p = string_ascii_p (string)) != 0)))
{
if (ascii_p > 0
|| (ascii_p < 0
&& (EQ (CODING_ID_EOL_TYPE (coding.id), Qunix)
|| inhibit_eol_conversion)))
return (nocopy
? string
: (encodep
? make_unibyte_string (SSDATA (string), bytes)
: make_multibyte_string (SSDATA (string),
bytes, bytes)));
}
? (chars == bytes) : string_ascii_p (string))
&& (EQ (CODING_ID_EOL_TYPE (coding.id), Qunix)
|| inhibit_eol_conversion
|| ! memchr (SDATA (string), encodep ? '\n' : '\r', bytes)))
return (nocopy
? string
: (encodep
? make_unibyte_string (SSDATA (string), bytes)
: make_multibyte_string (SSDATA (string), bytes, bytes)));
}
else if (BUFFERP (dst_object))
{

33
test/src/coding-tests.el
View file

@ -388,29 +388,38 @@
(let* ((uni (apply #'string (number-sequence 0 127)))
(multi (string-to-multibyte uni)))
(dolist (s (list uni multi))
;; Encodings without EOL conversion.
(dolist (coding '(us-ascii-unix iso-latin-1-unix utf-8-unix))
(should-not (eq (decode-coding-string s coding nil) s))
(should-not (eq (encode-coding-string s coding nil) s))
(should (eq (decode-coding-string s coding t) s))
(should (eq (encode-coding-string s coding t) s)))))
(let* ((uni (apply #'string (number-sequence 15 127)))
(should (eq (encode-coding-string s coding t) s)))
;; With EOL conversion inhibited.
(let ((inhibit-eol-conversion t))
(dolist (coding '(us-ascii iso-latin-1 utf-8))
(should-not (eq (decode-coding-string s coding nil) s))
(should-not (eq (encode-coding-string s coding nil) s))
(should (eq (decode-coding-string s coding t) s))
(should (eq (encode-coding-string s coding t) s))))))
;; Check identity decoding with EOL conversion for ASCII except CR.
(let* ((uni (apply #'string (delq ?\r (number-sequence 0 127))))
(multi (string-to-multibyte uni)))
(dolist (s (list uni multi))
(dolist (coding '(us-ascii iso-latin-1 utf-8))
(dolist (coding '(us-ascii-dos iso-latin-1-dos utf-8-dos mac-roman-mac))
(should-not (eq (decode-coding-string s coding nil) s))
(should-not (eq (encode-coding-string s coding nil) s))
(should (eq (decode-coding-string s coding t) s))
(should (eq (encode-coding-string s coding t) s)))))
(let* ((uni (apply #'string (number-sequence 0 127)))
(multi (string-to-multibyte uni))
(inhibit-eol-conversion t))
(should (eq (decode-coding-string s coding t) s)))))
;; Check identity encoding with EOL conversion for ASCII except LF.
(let* ((uni (apply #'string (delq ?\n (number-sequence 0 127))))
(multi (string-to-multibyte uni)))
(dolist (s (list uni multi))
(dolist (coding '(us-ascii iso-latin-1 utf-8))
(should-not (eq (decode-coding-string s coding nil) s))
(dolist (coding '(us-ascii-dos iso-latin-1-dos utf-8-dos mac-roman-mac))
(should-not (eq (encode-coding-string s coding nil) s))
(should (eq (decode-coding-string s coding t) s))
(should (eq (encode-coding-string s coding t) s))))))
(ert-deftest coding-check-coding-systems-region ()
(should (equal (check-coding-systems-region "aå" nil '(utf-8))
nil))