.\"	$NetBSD: strlist.9,v 1.3 2021/01/21 17:05:50 wiz Exp $
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.Dd January 20, 2021
.Dt OFSL 9
.Os
.Sh NAME
.Nm strlist ,
.Nm strlist_next ,
.Nm strlist_count ,
.Nm strlist_string ,
.Nm strlist_match ,
.Nm strlist_index ,
.Nm strlist_append
.Nd functions to interact with OpenFirmware-style string lists
.Sh SYNOPSIS
.In sys/systm.h
.Ft const char *
.Fn strlist_next "const char *sl" "size_t slsize" "size_t *cursorp"
.Ft void
.Fn strlist_count "const char *sl" "size_t slsize"
.Ft const char *
.Fn strlist_string "const char *sl" "size_t slsize" "unsigned int index"
.Ft int
.Fn strlist_match "const char *sl" "size_t slsize" "const char *str"
.Ft int
.Fn strlist_pmatch "const char *sl" "size_t slsize" "const char *pattern"
.Ft int
.Fn strlist_index "const char *sl" "size_t slsize" "const char *str"
.Ft bool
.Fn strlist_append "char **slp" "size_t *slsizep" "const char *str"
.Sh DESCRIPTION
The
.Nm
functions provide a simple way to interact with OpenFirmware
.Pq IEEE 1275
string lists.
.Pp
An OpenFirmware string list is simply a buffer containing one or more
NUL-terminated strings concatenated together.
For example, a string list containing the strings
.Dq foo ,
.Dq bar ,
and
.Dq baz
would be represented in memory as:
.Bd -literal -offset indent
foo\\0bar\\0baz\\0
.Ed
.Pp
The following functions are available:
.Bl -tag -width "xxxxx"
.It Fn strlist_next "const char *sl" "size_t slsize" "size_t *cursorp"
This function provides a way to enumerate the strings in a string list.
To enumerate a string list, initialize
.Fa cursor
to 0 and pass it by reference to
.Fn strlist_next .
Each call to
.Fn strlist_next
returns the current string and advances the cursor to the next string in
the list.
If all strings in the list have been enumerated,
.Fn strlist_next
will return
.Dv NULL .
.It Fn strlist_count "const char *sl" "size_t slsize"
Returns the number of strings in the string list.
.It Fn strlist_string "const char *sl" "size_t slsize" "unsigned int index"
Returns a pointer to the string in the string list at the specified
index or
.Dv NULL
if the index is out of range.
.It Fn strlist_match "const char *sl" "size_t slsize" "const char *str"
Returns a weighted match value if the specified string appears in
the string list.
The value returned is the number of strings in the string list
minus the index of the matched string.
For example, if a string list contains the strings
.Dq foo ,
.Dq bar ,
and
.Dq baz ,
a match against
.Dq foo
returns 3 and a match against
.Dq baz
returns 1.
If the string does not appear in the string list, 0 is returned.
.It Fn strlist_pmatch "const char *sl" "size_t slsize" "const char *pattern"
Like
.Fn strlist_match ,
but uses
.Fn pmatch
to compare strings, allowing for wildcard characters to be specified in
.Fa pattern .
.It Fn strlist_index "const char *sl" "size_t slsize" "const char *str"
Returns the index of the specified string if it appears in the
string list, or \-1 if the string does not appear in the string list.
.It Fn strlist_append "char **slp" "size_t *slsizep" "const char *str"
Appends a copy of the specified string to the stringlist.
Begin by initializing
.Fa sl
to
.Dv NULL
and
.Fa slsize
to 0.
Pass these by reference to
.Fn strlist_append .
New memory for the string list will be allocated as needed.
The resulting string list can be freed with
.Fn kmem_free .
Returns
.Dv true
if the string was successfully appended to the string list or
.Dv false
if memory allocation fails.
.El
.Sh EXAMPLES
The following shows an example of string list enumeration using
.Fn strlist_next :
.Bd -literal
void
print_stringlist(const char *sl, size_t slsize)
{
	const char *cp;
	size_t cursor;

	printf("There are %u strings in the string list:\\n",
	    strlist_count(sl, slsize));
	for (cursor = 0;
	     (cp = strlist_next(sl, slsize, &cursor) != NULL; ) {
		printf("\\t%s\\n", cp);
	}
}
.Ed
.Pp
The following example shows a simple way to use
.Fn strlist_match :
.Bd -literal
bool
is_compatible(int phandle, const char *compat_str)
{
	char buf[128];
	int proplen;

	proplen = OF_getprop(phandle, "compatible", buf, sizeof(buf));
	return strlist_match(buf, proplen, compat_str) != 0;
}
.Ed
.Pp
The following example shows a use of
.Fn strlist_pmatch :
.Bd -literal
bool
is_pc_printer_port(const char *pnp_id_list, size_t list_size)
{
	return strlist_pmatch(pnp_id_list, list_size, "PNP04??") != 0;
}
.Ed
.Pp
The following example converts an array of strings to a string list using
.Fn strlist_append :
.Bd -literal
char *
string_array_to_string_list(const char **array, int count,
    size_t *slsizep)
{
	char *sl;
	size_t slsize;
	int i;

	for (i = 0, sl = NULL, slsize = 0; i < count; i++) {
		if (!strlist_append(&sl, &slsize, array[i])) {
			kmem_free(sl, slsize);
			return NULL;
		}
	}

	*slsizep = slsize;
	return sl;
}
.Ed
.Sh SEE ALSO
.Xr kmem 9 ,
.Xr pmatch 9
.Sh HISTORY
The
.Nm
functions first appeared in
.Nx 10.0 .