iconv: Better mapping to RFC for UTF-7

- Direct use of characters instead of arcane arrays
- isxbase64 is not the Modified BASE64 alphabet, but the characters who
  needs to trigger an explicit shift back to US-ASCII. Make that clearer

Signed-off-by: Max Gautier <mg@max.gautier.name>
Reviewed-by: Adhemerval Zanellla  <adhemerval.zanella@linaro.org>
This commit is contained in:
Max Gautier 2022-03-20 17:41:05 +01:00 committed by Adhemerval Zanella
parent cd08388523
commit 09abb567a9

View File

@ -30,20 +30,27 @@
static bool
between (uint32_t const ch,
uint32_t const lower_bound, uint32_t const upper_bound)
{
return (ch >= lower_bound && ch <= upper_bound);
}
/* The set of "direct characters":
A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
*/
static const unsigned char direct_tab[128 / 8] =
{
0x00, 0x26, 0x00, 0x00, 0x81, 0xf3, 0xff, 0x87,
0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07
};
static int
static bool
isdirect (uint32_t ch)
{
return (ch < 128 && ((direct_tab[ch >> 3] >> (ch & 7)) & 1));
return (between (ch, 'A', 'Z')
|| between (ch, 'a', 'z')
|| between (ch, '0', '9')
|| ch == '\'' || ch == '(' || ch == ')'
|| between (ch, ',', '/')
|| ch == ':' || ch == '?'
|| ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
}
@ -52,33 +59,27 @@ isdirect (uint32_t ch)
! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
*/
static const unsigned char xdirect_tab[128 / 8] =
{
0x00, 0x26, 0x00, 0x00, 0xff, 0xf7, 0xff, 0xff,
0xff, 0xff, 0xff, 0xef, 0xff, 0xff, 0xff, 0x3f
};
static int
static bool
isxdirect (uint32_t ch)
{
return (ch < 128 && ((xdirect_tab[ch >> 3] >> (ch & 7)) & 1));
return (ch == '\t'
|| ch == '\n'
|| ch == '\r'
|| (between (ch, ' ', '}') && ch != '+' && ch != '\\'));
}
/* The set of "extended base64 characters":
/* Characters which needs to trigger an explicit shift back to US-ASCII (UTF-7
only): Modified base64 + '-' (shift back character)
A-Z a-z 0-9 + / -
*/
static const unsigned char xbase64_tab[128 / 8] =
{
0x00, 0x00, 0x00, 0x00, 0x00, 0xa8, 0xff, 0x03,
0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07
};
static int
isxbase64 (uint32_t ch)
static bool
needs_explicit_shift (uint32_t ch)
{
return (ch < 128 && ((xbase64_tab[ch >> 3] >> (ch & 7)) & 1));
return (between (ch, 'A', 'Z')
|| between (ch, 'a', 'z')
|| between (ch, '/', '9') || ch == '+' || ch == '-');
}
@ -252,7 +253,7 @@ base64 (unsigned int i)
indeed form a Low Surrogate. */ \
uint32_t wc2 = wch & 0xffff; \
\
if (! __builtin_expect (wc2 >= 0xdc00 && wc2 < 0xe000, 1)) \
if (! __glibc_likely (wc2 >= 0xdc00 && wc2 < 0xe000)) \
{ \
STANDARD_FROM_LOOP_ERR_HANDLER ((statep->__count = 0, 1));\
} \
@ -372,7 +373,8 @@ base64 (unsigned int i)
/* deactivate base64 encoding */ \
size_t count; \
\
count = ((statep->__count & 0x18) >= 0x10) + isxbase64 (ch) + 1; \
count = ((statep->__count & 0x18) >= 0x10) \
+ needs_explicit_shift (ch) + 1; \
if (__glibc_unlikely (outptr + count > outend)) \
{ \
result = __GCONV_FULL_OUTPUT; \
@ -381,7 +383,7 @@ base64 (unsigned int i)
\
if ((statep->__count & 0x18) >= 0x10) \
*outptr++ = base64 ((statep->__count >> 3) & ~3); \
if (isxbase64 (ch)) \
if (needs_explicit_shift (ch)) \
*outptr++ = '-'; \
*outptr++ = (unsigned char) ch; \
statep->__count = 0; \