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SubjectRe: [PATCH] Add lib/parser.c kernel-doc
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On Sun, 2003-11-16 at 03:16, Will Dyson wrote:
> When I converted befs's option parsing to use the new lib/parser.c
> functions, I had to read the functions (and the patch converting ext3)
> in order to understand exactly how to use them. They are not that
> complicated, but since I'd already read and (hopefully) understood the
> functions, I figured I'd add a bit of documentation for others.
>
> I am not the author of the functions I am attempting to document here,
> so any mistakes are just that: mistakes on my part.

Here is take 2, incorporating Matthew Wilcox's suggestions and sent as
an attatchment to avoid word-wrap.

--
Will Dyson
"Back off man, I'm a scientist!" -Dr. Peter Venkman
# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
# ChangeSet 1.1352 -> 1.1354
# lib/parser.c 1.2 -> 1.4
# include/linux/parser.h 1.1 -> 1.3
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/11/16 will@thalience.(none) 1.1353
# Add documentation and comments to lib/parser.c and include/linux/parser.h
# --------------------------------------------
# 03/11/16 will@thalience.(none) 1.1354
# Incorporate fixes/suggestions from Matthew Wilcox
# --------------------------------------------
#
diff -Nru a/include/linux/parser.h b/include/linux/parser.h
--- a/include/linux/parser.h Sun Nov 16 17:32:10 2003
+++ b/include/linux/parser.h Sun Nov 16 17:32:10 2003
@@ -1,3 +1,14 @@
+/*
+ * linux/include/linux/parser.h
+ *
+ * Header for lib/parser.c
+ * Intended use of these functions is parsing filesystem argument lists,
+ * but could potentially be used anywhere else that simple option=arg
+ * parsing is required.
+ */
+
+
+/* associates an integer enumerator with a pattern string. */
struct match_token {
int token;
char *pattern;
@@ -5,15 +16,16 @@

typedef struct match_token match_table_t[];

+/* Maximum number of arguments that match_token will find in a pattern */
enum {MAX_OPT_ARGS = 3};

+/* Describe the location within a string of a substring */
typedef struct {
char *from;
char *to;
} substring_t;

-int match_token(char *s, match_table_t table, substring_t args[]);
-
+int match_token(char *, match_table_t table, substring_t args[]);
int match_int(substring_t *, int *result);
int match_octal(substring_t *, int *result);
int match_hex(substring_t *, int *result);
diff -Nru a/lib/parser.c b/lib/parser.c
--- a/lib/parser.c Sun Nov 16 17:32:10 2003
+++ b/lib/parser.c Sun Nov 16 17:32:10 2003
@@ -11,6 +11,17 @@
#include <linux/slab.h>
#include <linux/string.h>

+/**
+ * match_one: - Determines if a string matches a simple pattern
+ * @s: the string to examine for presense of the pattern
+ * @p: the string containing the pattern
+ * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
+ * locations.
+ *
+ * Description: Determines if the pattern @p is present in string @s. Can only
+ * match extremely simple token=arg style patterns. If the pattern is found,
+ * the location(s) of the arguments will be returned in the @args array.
+ */
static int match_one(char *s, char *p, substring_t args[])
{
char *meta;
@@ -74,6 +85,20 @@
}
}

+/**
+ * match_token: - Find a token (and optional args) in a string
+ * @s: the string to examine for token/argument pairs
+ * @table: match_table_t describing the set of allowed option tokens and the
+ * arguments that may be associated with them. Must be terminated with a
+ * &struct match_token whose pattern is set to the NULL pointer.
+ * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
+ * locations.
+ *
+ * Description: Detects which if any of a set of token strings has been passed
+ * to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style
+ * format identifiers which will be taken into account when matching the
+ * tokens, and whose locations will be returned in the @args array.
+ */
int match_token(char *s, match_table_t table, substring_t args[])
{
struct match_token *p;
@@ -84,6 +109,16 @@
return p->token;
}

+/**
+ * match_number: scan a number in the given base from a substring_t
+ * @s: substring to be scanned
+ * @result: resulting integer on success
+ * @base: base to use when converting string
+ *
+ * Description: Given a &substring_t and a base, attempts to parse the substring
+ * as a number in that base. On success, sets @result to the integer represented
+ * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
+ */
static int match_number(substring_t *s, int *result, int base)
{
char *endp;
@@ -103,27 +138,71 @@
return ret;
}

+/**
+ * match_int: - scan a decimal representation of an integer from a substring_t
+ * @s: substring_t to be scanned
+ * @result: resulting integer on success
+ *
+ * Description: Attempts to parse the &substring_t @s as a decimal integer. On
+ * success, sets @result to the integer represented by the string and returns 0.
+ * Returns either -ENOMEM or -EINVAL on failure.
+ */
int match_int(substring_t *s, int *result)
{
return match_number(s, result, 0);
}

+/**
+ * match_octal: - scan an octal representation of an integer from a substring_t
+ * @s: substring_t to be scanned
+ * @result: resulting integer on success
+ *
+ * Description: Attempts to parse the &substring_t @s as an octal integer. On
+ * success, sets @result to the integer represented by the string and returns
+ * 0. Returns either -ENOMEM or -EINVAL on failure.
+ */
int match_octal(substring_t *s, int *result)
{
return match_number(s, result, 8);
}

+/**
+ * match_hex: - scan a hex representation of an integer from a substring_t
+ * @s: substring_t to be scanned
+ * @result: resulting integer on success
+ *
+ * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
+ * On success, sets @result to the integer represented by the string and
+ * returns 0. Returns either -ENOMEM or -EINVAL on failure.
+ */
int match_hex(substring_t *s, int *result)
{
return match_number(s, result, 16);
}

+/**
+ * match_strcpy: - copies the characters from a substring_t to a string
+ * @to: string to copy characters to.
+ * @s: &substring_t to copy
+ *
+ * Description: Copies the set of characters represented by the given
+ * &substring_t @s to the c-style string @to. Caller guarantees that @to is
+ * large enough to hold the characters of @s.
+ */
void match_strcpy(char *to, substring_t *s)
{
memcpy(to, s->from, s->to - s->from);
to[s->to - s->from] = '\0';
}

+/**
+ * match_strdup: - allocate a new string with the contents of a substring_t
+ * @s: &substring_t to copy
+ *
+ * Description: Allocates and returns a string filled with the contents of
+ * the &substring_t @s. The caller is responsible for freeing the returned
+ * string with kfree().
+ */
char *match_strdup(substring_t *s)
{
char *p = kmalloc(s->to - s->from + 1, GFP_KERNEL);
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