[v5,3/4] iconv: make utf-7.c able to use variants

  Add infrastructure in utf-7.c to handle variants. The approach comes from
iso646.c
The variant is defined at gconv_init time and is passed as a
supplementary variable.

Signed-off-by: Max Gautier <mg@max.gautier.name>
---
 iconvdata/utf-7.c | 230 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 170 insertions(+), 60 deletions(-)
  

On 20/03/2022 13:42, Max Gautier via Libc-alpha wrote:
> Add infrastructure in utf-7.c to handle variants. The approach comes from
> iso646.c
> The variant is defined at gconv_init time and is passed as a
> supplementary variable.
> 
> Signed-off-by: Max Gautier <mg@max.gautier.name>

Patch looks ok, although it should be refactor to add 'enum variant' argument
on isdirect and isxdirect instead of relying on previous patch (to keep the
patch consistent).

> ---
>  iconvdata/utf-7.c | 230 ++++++++++++++++++++++++++++++++++------------
>  1 file changed, 170 insertions(+), 60 deletions(-)
> 
> diff --git a/iconvdata/utf-7.c b/iconvdata/utf-7.c
> index 15f3669ac8..b639d8ff3e 100644
> --- a/iconvdata/utf-7.c
> +++ b/iconvdata/utf-7.c
> @@ -29,6 +29,24 @@
>  #include <stdlib.h>
>  
>  
> +enum variant
> +{
> +  UTF7,
> +};
> +
> +/* Must be in the same order as enum variant above.  */
> +static const char names[] =
> +  "UTF-7//\0"
> +  "\0";
> +
> +static uint32_t
> +shift_character (enum variant const var)
> +{
> +  if (var == UTF7)
> +    return '+';
> +  else
> +    abort ();
> +}
>  
>  static bool
>  between (uint32_t const ch,
> @@ -38,23 +56,27 @@ between (uint32_t const ch,
>  }
>  
>  /* The set of "direct characters":
> +   FOR UTF-7
>     A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
>  */
>  
>  static bool
>  isdirect (uint32_t ch, enum variant var)
>  {
> -  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');
> +  if (var == UTF7)
> +    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');
> +  abort ();
>  }
>  
>  
>  /* The set of "direct and optional direct characters":
> +   (UTF-7 only)
>     A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
>     ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
>  */
> @@ -62,10 +84,15 @@ isdirect (uint32_t ch, enum variant var)
>  static bool
>  isxdirect (uint32_t ch, enum variant var)
>  {
> -  return (ch == '\t'
> -	  || ch == '\n'
> -	  || ch == '\r'
> -	  || (between (ch, ' ', '}') && ch != '+' && ch != '\\'));
> +  if (isdirect (ch, var))
> +    return true;
> +  if (var != UTF7)
> +    return false;
> +  return between (ch, '!', '&')
> +    || ch == '*'
> +    || between (ch, ';', '@')
> +    || (between (ch, '[', '`') && ch != '\\')
> +    || between (ch, '{', '}');
>  }
>  
>  
> @@ -85,7 +112,7 @@ needs_explicit_shift (uint32_t ch)
>  
>  /* Converts a value in the range 0..63 to a base64 encoded char.  */
>  static unsigned char
> -base64 (unsigned int i)
> +base64 (unsigned int i, enum variant var)
>  {
>    if (i < 26)
>      return i + 'A';
> @@ -95,7 +122,7 @@ base64 (unsigned int i)
>      return i - 52 + '0';
>    else if (i == 62)
>      return '+';
> -  else if (i == 63)
> +  else if (i == 63 && var == UTF7)
>      return '/';
>    else
>      abort ();
> @@ -103,9 +130,8 @@ base64 (unsigned int i)
>  
>  
>  /* Definitions used in the body of the `gconv' function.  */
> -#define CHARSET_NAME		"UTF-7//"
> -#define DEFINE_INIT		1
> -#define DEFINE_FINI		1
> +#define DEFINE_INIT		0
> +#define DEFINE_FINI		0
>  #define FROM_LOOP		from_utf7_loop
>  #define TO_LOOP			to_utf7_loop
>  #define MIN_NEEDED_FROM		1
> @@ -113,11 +139,27 @@ base64 (unsigned int i)
>  #define MIN_NEEDED_TO		4
>  #define MAX_NEEDED_TO		4
>  #define ONE_DIRECTION		0
> +#define FROM_DIRECTION      (dir == from_utf7)
>  #define PREPARE_LOOP \
>    mbstate_t saved_state;						      \
> -  mbstate_t *statep = data->__statep;
> -#define EXTRA_LOOP_ARGS		, statep
> +  mbstate_t *statep = data->__statep;					      \
> +  enum direction dir = ((struct utf7_data *) step->__data)->dir;	      \
> +  enum direction var = ((struct utf7_data *) step->__data)->var;
> +#define EXTRA_LOOP_ARGS		, statep, var
> +
>  
> +enum direction
> +{
> +  illegal_dir,
> +  from_utf7,
> +  to_utf7
> +};
> +
> +struct utf7_data
> +{
> +  enum direction dir;
> +  enum variant var;
> +};
>  
>  /* Since we might have to reset input pointer we must be able to save
>     and restore the state.  */
> @@ -127,6 +169,70 @@ base64 (unsigned int i)
>    else									      \
>      *statep = saved_state
>  
> +int
> +gconv_init (struct __gconv_step *step)
> +{
> +  /* Determine which direction.  */
> +  struct utf7_data *new_data;
> +  enum direction dir = illegal_dir;
> +
> +  enum variant var = 0;
> +  for (const char *name = names; *name != '\0';
> +       name = __rawmemchr (name, '\0') + 1)
> +    {
> +      if (__strcasecmp (step->__from_name, name) == 0)
> +	{
> +	  dir = from_utf7;
> +	  break;
> +	}
> +      else if (__strcasecmp (step->__to_name, name) == 0)
> +	{
> +	  dir = to_utf7;
> +	  break;
> +	}
> +      ++var;
> +    }
> +
> +  if (__glibc_likely (dir != illegal_dir))
> +    {
> +      new_data = malloc (sizeof (*new_data));
> +      if (new_data == NULL)
> +	return __GCONV_NOMEM;
> +
> +      new_data->dir = dir;
> +      new_data->var = var;
> +      step->__data = new_data;
> +
> +      if (dir == from_utf7)
> +	{
> +	  step->__min_needed_from = MIN_NEEDED_FROM;
> +	  step->__max_needed_from = MAX_NEEDED_FROM;
> +	  step->__min_needed_to = MIN_NEEDED_TO;
> +	  step->__max_needed_to = MAX_NEEDED_TO;
> +	}
> +      else
> +	{
> +	  step->__min_needed_from = MIN_NEEDED_TO;
> +	  step->__max_needed_from = MAX_NEEDED_TO;
> +	  step->__min_needed_to = MIN_NEEDED_FROM;
> +	  step->__max_needed_to = MAX_NEEDED_FROM;
> +	}
> +    }
> +  else
> +    return __GCONV_NOCONV;
> +
> +  step->__stateful = 1;
> +
> +  return __GCONV_OK;
> +}
> +
> +void
> +gconv_end (struct __gconv_step *data)
> +{
> +  free (data->__data);
> +}
> +
> +
>  
>  /* First define the conversion function from UTF-7 to UCS4.
>     The state is structured as follows:
> @@ -154,13 +260,13 @@ base64 (unsigned int i)
>      if ((statep->__count >> 3) == 0)					      \
>        {									      \
>  	/* base64 encoding inactive.  */				      \
> -	if (isxdirect (ch))						      \
> +	if (isxdirect (ch, var))					      \
>  	  {								      \
>  	    inptr++;							      \
>  	    put32 (outptr, ch);						      \
>  	    outptr += 4;						      \
>  	  }								      \
> -	else if (__glibc_likely (ch == '+'))				      \
> +	else if (__glibc_likely (ch == shift_character (var)))		      \
>  	  {								      \
>  	    if (__glibc_unlikely (inptr + 2 > inend))			      \
>  	      {								      \
> @@ -285,7 +391,7 @@ base64 (unsigned int i)
>        }									      \
>    }
>  #define LOOP_NEED_FLAGS
> -#define EXTRA_LOOP_DECLS	, mbstate_t *statep
> +#define EXTRA_LOOP_DECLS	, mbstate_t *statep, enum variant var
>  #include <iconv/loop.c>
>  
>  
> @@ -316,7 +422,7 @@ base64 (unsigned int i)
>      if ((statep->__count & 0x18) == 0)					      \
>        {									      \
>  	/* base64 encoding inactive */					      \
> -	if (isdirect (ch))   						      \
> +	if (isdirect (ch, var))						      \
>  	  {								      \
>  	    *outptr++ = (unsigned char) ch;				      \
>  	  }								      \
> @@ -324,7 +430,7 @@ base64 (unsigned int i)
>  	  {								      \
>  	    size_t count;						      \
>  									      \
> -	    if (ch == '+')						      \
> +	    if (ch == shift_character (var))				      \
>  	      count = 2;						      \
>  	    else if (ch < 0x10000)					      \
>  	      count = 3;						      \
> @@ -339,13 +445,13 @@ base64 (unsigned int i)
>  		break;							      \
>  	      }								      \
>  									      \
> -	    *outptr++ = '+';						      \
> -	    if (ch == '+')						      \
> +	    *outptr++ = shift_character (var);				      \
> +	    if (ch == shift_character (var))				      \
>  	      *outptr++ = '-';						      \
>  	    else if (ch < 0x10000)					      \
>  	      {								      \
> -		*outptr++ = base64 (ch >> 10);				      \
> -		*outptr++ = base64 ((ch >> 4) & 0x3f);			      \
> +		*outptr++ = base64 (ch >> 10, var);			      \
> +		*outptr++ = base64 ((ch >> 4) & 0x3f, var);		      \
>  		statep->__count = ((ch & 15) << 5) | (3 << 3);		      \
>  	      }								      \
>  	    else if (ch < 0x110000)					      \
> @@ -354,11 +460,11 @@ base64 (unsigned int i)
>  		uint32_t ch2 = 0xdc00 + ((ch - 0x10000) & 0x3ff);	      \
>  									      \
>  		ch = (ch1 << 16) | ch2;					      \
> -		*outptr++ = base64 (ch >> 26);				      \
> -		*outptr++ = base64 ((ch >> 20) & 0x3f);			      \
> -		*outptr++ = base64 ((ch >> 14) & 0x3f);			      \
> -		*outptr++ = base64 ((ch >> 8) & 0x3f);			      \
> -		*outptr++ = base64 ((ch >> 2) & 0x3f);			      \
> +		*outptr++ = base64 (ch >> 26, var);			      \
> +		*outptr++ = base64 ((ch >> 20) & 0x3f, var);		      \
> +		*outptr++ = base64 ((ch >> 14) & 0x3f, var);		      \
> +		*outptr++ = base64 ((ch >> 8) & 0x3f, var);		      \
> +		*outptr++ = base64 ((ch >> 2) & 0x3f, var);		      \
>  		statep->__count = ((ch & 3) << 7) | (2 << 3);		      \
>  	      }								      \
>  	    else							      \
> @@ -368,7 +474,7 @@ base64 (unsigned int i)
>      else								      \
>        {									      \
>  	/* base64 encoding active */					      \
> -	if (isdirect (ch))						      \
> +	if (isdirect (ch, var))						      \
>  	  {								      \
>  	    /* deactivate base64 encoding */				      \
>  	    size_t count;						      \
> @@ -382,7 +488,7 @@ base64 (unsigned int i)
>  	      }								      \
>  									      \
>  	    if ((statep->__count & 0x18) >= 0x10)			      \
> -	      *outptr++ = base64 ((statep->__count >> 3) & ~3);		      \
> +	      *outptr++ = base64 ((statep->__count >> 3) & ~3, var);	      \
>  	    if (needs_explicit_shift (ch))				      \
>  	      *outptr++ = '-';						      \
>  	    *outptr++ = (unsigned char) ch;				      \
> @@ -410,22 +516,24 @@ base64 (unsigned int i)
>  		switch ((statep->__count >> 3) & 3)			      \
>  		  {							      \
>  		  case 1:						      \
> -		    *outptr++ = base64 (ch >> 10);			      \
> -		    *outptr++ = base64 ((ch >> 4) & 0x3f);		      \
> +		    *outptr++ = base64 (ch >> 10, var);			      \
> +		    *outptr++ = base64 ((ch >> 4) & 0x3f, var);		      \
>  		    statep->__count = ((ch & 15) << 5) | (3 << 3);	      \
>  		    break;						      \
>  		  case 2:						      \
>  		    *outptr++ =						      \
> -		      base64 (((statep->__count >> 3) & ~3) | (ch >> 12));    \
> -		    *outptr++ = base64 ((ch >> 6) & 0x3f);		      \
> -		    *outptr++ = base64 (ch & 0x3f);			      \
> +		      base64 (((statep->__count >> 3) & ~3) | (ch >> 12),     \
> +			      var);					      \
> +		    *outptr++ = base64 ((ch >> 6) & 0x3f, var);		      \
> +		    *outptr++ = base64 (ch & 0x3f, var);		      \
>  		    statep->__count = (1 << 3);				      \
>  		    break;						      \
>  		  case 3:						      \
>  		    *outptr++ =						      \
> -		      base64 (((statep->__count >> 3) & ~3) | (ch >> 14));    \
> -		    *outptr++ = base64 ((ch >> 8) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 2) & 0x3f);		      \
> +		      base64 (((statep->__count >> 3) & ~3) | (ch >> 14),     \
> +			      var);					      \
> +		    *outptr++ = base64 ((ch >> 8) & 0x3f, var);		      \
> +		    *outptr++ = base64 ((ch >> 2) & 0x3f, var);		      \
>  		    statep->__count = ((ch & 3) << 7) | (2 << 3);	      \
>  		    break;						      \
>  		  default:						      \
> @@ -441,30 +549,32 @@ base64 (unsigned int i)
>  		switch ((statep->__count >> 3) & 3)			      \
>  		  {							      \
>  		  case 1:						      \
> -		    *outptr++ = base64 (ch >> 26);			      \
> -		    *outptr++ = base64 ((ch >> 20) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 14) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 8) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 2) & 0x3f);		      \
> +		    *outptr++ = base64 (ch >> 26, var);			      \
> +		    *outptr++ = base64 ((ch >> 20) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 14) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 8) & 0x3f, var);		      \
> +		    *outptr++ = base64 ((ch >> 2) & 0x3f, var);		      \
>  		    statep->__count = ((ch & 3) << 7) | (2 << 3);	      \
>  		    break;						      \
>  		  case 2:						      \
>  		    *outptr++ =						      \
> -		      base64 (((statep->__count >> 3) & ~3) | (ch >> 28));    \
> -		    *outptr++ = base64 ((ch >> 22) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 16) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 10) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 4) & 0x3f);		      \
> +		      base64 (((statep->__count >> 3) & ~3) | (ch >> 28),     \
> +			      var);					      \
> +		    *outptr++ = base64 ((ch >> 22) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 16) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 10) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 4) & 0x3f, var);		      \
>  		    statep->__count = ((ch & 15) << 5) | (3 << 3);	      \
>  		    break;						      \
>  		  case 3:						      \
>  		    *outptr++ =						      \
> -		      base64 (((statep->__count >> 3) & ~3) | (ch >> 30));    \
> -		    *outptr++ = base64 ((ch >> 24) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 18) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 12) & 0x3f);		      \
> -		    *outptr++ = base64 ((ch >> 6) & 0x3f);		      \
> -		    *outptr++ = base64 (ch & 0x3f);			      \
> +		      base64 (((statep->__count >> 3) & ~3) | (ch >> 30),     \
> +			      var);					      \
> +		    *outptr++ = base64 ((ch >> 24) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 18) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 12) & 0x3f, var);	      \
> +		    *outptr++ = base64 ((ch >> 6) & 0x3f, var);		      \
> +		    *outptr++ = base64 (ch & 0x3f, var);		      \
>  		    statep->__count = (1 << 3);				      \
>  		    break;						      \
>  		  default:						      \
> @@ -480,7 +590,7 @@ base64 (unsigned int i)
>      inptr += 4;								      \
>    }
>  #define LOOP_NEED_FLAGS
> -#define EXTRA_LOOP_DECLS	, mbstate_t *statep
> +#define EXTRA_LOOP_DECLS	, mbstate_t *statep, enum variant var
>  #include <iconv/loop.c>
>  
>  
> @@ -510,7 +620,7 @@ base64 (unsigned int i)
>  	    {								      \
>  	      /* Write out the shift sequence.  */			      \
>  	      if ((state & 0x18) >= 0x10)				      \
> -		*outbuf++ = base64 ((state >> 3) & ~3);			      \
> +		*outbuf++ = base64 ((state >> 3) & ~3, var);		      \
>  	      *outbuf++ = '-';						      \
>  									      \
>  	      data->__statep->__count = 0;				      \