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Fix `get_utf8_codepoint' to not consume valid starting bytes.

Browse source 
Thanks to Mark H. Weaver for pointing this out.

* libguile/ports.c (CONSUME_PEEKED_BYTE): New macro.
  (get_utf8_codepoint): New variable `pt'.  Use
  `scm_peek_byte_or_eof'/`CONSUME_PEEKED_BYTE' pairs instead of
  `scm_get_byte_or_eof'.

* test-suite/tests/ports.test ("string ports")[#xc2 #x41 #x42, #xe0 #xa0
  #x41 #x42, #xf0 #x88 #x88 #x88]: Fix to conform to Unicode 6.0.0.
  [#xe0 #x88 #x88]: Remove test.
  [#xf0 #x80 #x80 #x41]: New test.
This commit is contained in:
Ludovic Courtès 2011-05-07 22:46:38 +02:00
parent 452c5ad912
commit 7be1705dbd
2 changed files with 67 additions and 64 deletions
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100
libguile/ports.c
View file

@ -1127,10 +1127,14 @@ get_utf8_codepoint (SCM port, scm_t_wchar *codepoint,
#define ASSERT_NOT_EOF(b) \ #define ASSERT_NOT_EOF(b) \
if (SCM_UNLIKELY ((b) == EOF)) \ if (SCM_UNLIKELY ((b) == EOF)) \
goto invalid_seq goto invalid_seq
#define CONSUME_PEEKED_BYTE() \
pt->read_pos++
int byte; int byte;
scm_t_port *pt;
*len = 0; *len = 0;
pt = SCM_PTAB_ENTRY (port);
byte = scm_get_byte_or_eof (port); byte = scm_get_byte_or_eof (port);
if (byte == EOF) if (byte == EOF)
@ -1148,49 +1152,44 @@ get_utf8_codepoint (SCM port, scm_t_wchar *codepoint,
else if (buf[0] >= 0xc2 && buf[0] <= 0xdf) else if (buf[0] >= 0xc2 && buf[0] <= 0xdf)
{ {
/* 2-byte form. */ /* 2-byte form. */
byte = scm_get_byte_or_eof (port); byte = scm_peek_byte_or_eof (port);
ASSERT_NOT_EOF (byte); ASSERT_NOT_EOF (byte);
buf[1] = (scm_t_uint8) byte;
*len = 2;
if (SCM_UNLIKELY ((byte & 0xc0) != 0x80)) if (SCM_UNLIKELY ((byte & 0xc0) != 0x80))
goto invalid_seq; goto invalid_seq;
CONSUME_PEEKED_BYTE ();
buf[1] = (scm_t_uint8) byte;
*len = 2;
*codepoint = ((scm_t_wchar) buf[0] & 0x1f) << 6UL *codepoint = ((scm_t_wchar) buf[0] & 0x1f) << 6UL
| (buf[1] & 0x3f); | (buf[1] & 0x3f);
} }
else if ((buf[0] & 0xf0) == 0xe0) else if ((buf[0] & 0xf0) == 0xe0)
{ {
/* 3-byte form. */ /* 3-byte form. */
byte = scm_get_byte_or_eof (port); byte = scm_peek_byte_or_eof (port);
if (SCM_UNLIKELY (byte == EOF)) ASSERT_NOT_EOF (byte);
goto invalid_seq;
buf[1] = (scm_t_uint8) byte;
*len = 2;
if (SCM_UNLIKELY ((byte & 0xc0) != 0x80 if (SCM_UNLIKELY ((byte & 0xc0) != 0x80
|| (buf[0] == 0xe0 && byte < 0xa0) || (buf[0] == 0xe0 && byte < 0xa0)
|| (buf[0] == 0xed && byte > 0x9f))) || (buf[0] == 0xed && byte > 0x9f)))
{ goto invalid_seq;
/* Swallow the 3rd byte. */
byte = scm_get_byte_or_eof (port);
ASSERT_NOT_EOF (byte);
*len = 3, buf[2] = byte;
goto invalid_seq;
}
CONSUME_PEEKED_BYTE ();
buf[1] = (scm_t_uint8) byte;
*len = 2;
byte = scm_get_byte_or_eof (port); byte = scm_peek_byte_or_eof (port);
ASSERT_NOT_EOF (byte); ASSERT_NOT_EOF (byte);
buf[2] = (scm_t_uint8) byte;
*len = 3;
if (SCM_UNLIKELY ((byte & 0xc0) != 0x80)) if (SCM_UNLIKELY ((byte & 0xc0) != 0x80))
goto invalid_seq; goto invalid_seq;
CONSUME_PEEKED_BYTE ();
buf[2] = (scm_t_uint8) byte;
*len = 3;
*codepoint = ((scm_t_wchar) buf[0] & 0x0f) << 12UL *codepoint = ((scm_t_wchar) buf[0] & 0x0f) << 12UL
| ((scm_t_wchar) buf[1] & 0x3f) << 6UL | ((scm_t_wchar) buf[1] & 0x3f) << 6UL
| (buf[2] & 0x3f); | (buf[2] & 0x3f);
@ -1198,51 +1197,38 @@ get_utf8_codepoint (SCM port, scm_t_wchar *codepoint,
else if (buf[0] >= 0xf0 && buf[0] <= 0xf4) else if (buf[0] >= 0xf0 && buf[0] <= 0xf4)
{ {
/* 4-byte form. */ /* 4-byte form. */
byte = scm_get_byte_or_eof (port); byte = scm_peek_byte_or_eof (port);
ASSERT_NOT_EOF (byte); ASSERT_NOT_EOF (byte);
buf[1] = (scm_t_uint8) byte;
*len = 2;
if (SCM_UNLIKELY (((byte & 0xc0) != 0x80) if (SCM_UNLIKELY (((byte & 0xc0) != 0x80)
|| (buf[0] == 0xf0 && byte < 0x90) || (buf[0] == 0xf0 && byte < 0x90)
|| (buf[0] == 0xf4 && byte > 0x8f))) || (buf[0] == 0xf4 && byte > 0x8f)))
{ goto invalid_seq;
/* Swallow the 3rd and 4th bytes. */
byte = scm_get_byte_or_eof (port);
ASSERT_NOT_EOF (byte);
*len = 3, buf[2] = byte;
byte = scm_get_byte_or_eof (port); CONSUME_PEEKED_BYTE ();
ASSERT_NOT_EOF (byte); buf[1] = (scm_t_uint8) byte;
*len = 4, buf[3] = byte; *len = 2;
goto invalid_seq;
}
byte = scm_get_byte_or_eof (port); byte = scm_peek_byte_or_eof (port);
ASSERT_NOT_EOF (byte); ASSERT_NOT_EOF (byte);
buf[2] = (scm_t_uint8) byte;
*len = 3;
if (SCM_UNLIKELY ((byte & 0xc0) != 0x80))
{
/* Swallow the 4th byte. */
byte = scm_get_byte_or_eof (port);
ASSERT_NOT_EOF (byte);
*len = 4, buf[3] = byte;
goto invalid_seq;
}
byte = scm_get_byte_or_eof (port);
ASSERT_NOT_EOF (byte);
buf[3] = (scm_t_uint8) byte;
*len = 4;
if (SCM_UNLIKELY ((byte & 0xc0) != 0x80)) if (SCM_UNLIKELY ((byte & 0xc0) != 0x80))
goto invalid_seq; goto invalid_seq;
CONSUME_PEEKED_BYTE ();
buf[2] = (scm_t_uint8) byte;
*len = 3;
byte = scm_peek_byte_or_eof (port);
ASSERT_NOT_EOF (byte);
if (SCM_UNLIKELY ((byte & 0xc0) != 0x80))
goto invalid_seq;
CONSUME_PEEKED_BYTE ();
buf[3] = (scm_t_uint8) byte;
*len = 4;
*codepoint = ((scm_t_wchar) buf[0] & 0x07) << 18UL *codepoint = ((scm_t_wchar) buf[0] & 0x07) << 18UL
| ((scm_t_wchar) buf[1] & 0x3f) << 12UL | ((scm_t_wchar) buf[1] & 0x3f) << 12UL
| ((scm_t_wchar) buf[2] & 0x3f) << 6UL | ((scm_t_wchar) buf[2] & 0x3f) << 6UL
@ -1254,8 +1240,14 @@ get_utf8_codepoint (SCM port, scm_t_wchar *codepoint,
return 0; return 0;
invalid_seq: invalid_seq:
/* Here we could choose the consume the faulty byte when it's not a
valid starting byte, but it's not a requirement. What Section 3.9
of Unicode 6.0.0 mandates, though, is to not consume a byte that
would otherwise be a valid starting byte. */
return EILSEQ; return EILSEQ;
#undef CONSUME_PEEKED_BYTE
#undef ASSERT_NOT_EOF #undef ASSERT_NOT_EOF
} }

31
test-suite/tests/ports.test
View file

@ -572,29 +572,40 @@
eof)) eof))
(test-decoding-error (#xc2 #x41 #x42) "UTF-8" (test-decoding-error (#xc2 #x41 #x42) "UTF-8"
;; FIXME: This is the behavior of glibc/libiconv but it does not ;; Section 3.9 of Unicode 6.0.0 reads:
;; conform to the Unicode 6.0.0 recommendation: according to it, ;; "If the converter encounters an ill-formed UTF-8 code unit
;; the #\A should not be swallowed (Section 3.9 reads: ;; sequence which starts with a valid first byte, but which does
;; "If the converter encounters an ill-formed UTF-8 code unit ;; not continue with valid successor bytes (see Table 3-7), it
;; sequence which starts with a valid first byte, but which does ;; must not consume the successor bytes".
;; not continue with valid successor bytes (see Table 3-7), it ;; Glibc/libiconv do not conform to it and instead swallow the
;; must not consume the successor bytes".) ;; #x41. This example appears literally in Section 3.9.
(error ;; 41: invalid successor
(error ;; 41: should be in the 80..BF range #\A ;; 41: valid starting byte
#\B #\B
eof)) eof))
(test-decoding-error (#xe0 #x88 #x88) "UTF-8" (test-decoding-error (#xf0 #x80 #x80 #x41) "UTF-8"
;; According to Unicode 6.0.0, Section 3.9, "the only formal
;; requirement mandated by Unicode conformance for a converter is
;; that the <41> be processed and correctly interpreted as
;; <U+0041>".
(error ;; 2nd byte should be in the A0..BF range (error ;; 2nd byte should be in the A0..BF range
error ;; 80: not a valid starting byte
error ;; 80: not a valid starting byte
#\A
eof)) eof))
(test-decoding-error (#xe0 #xa0 #x41 #x42) "UTF-8" (test-decoding-error (#xe0 #xa0 #x41 #x42) "UTF-8"
(error ;; 3rd byte should be in the 80..BF range (error ;; 3rd byte should be in the 80..BF range
#\A
#\B #\B
eof)) eof))
(test-decoding-error (#xf0 #x88 #x88 #x88) "UTF-8" (test-decoding-error (#xf0 #x88 #x88 #x88) "UTF-8"
(error ;; 2nd byte should be in the 90..BF range (error ;; 2nd byte should be in the 90..BF range
error ;; 88: not a valid starting byte
error ;; 88: not a valid starting byte
error ;; 88: not a valid starting byte
eof)))) eof))))
(with-test-prefix "call-with-output-string" (with-test-prefix "call-with-output-string"