Patchwork [U-Boot,1/2] Add SLRE - Super Light Regular Expression library

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Submitter Wolfgang Denk
Date Nov. 6, 2011, 7:55 p.m.
Message ID <1320609326-3259-1-git-send-email-wd@denx.de>
Download mbox | patch
Permalink /patch/123963/
State Deferred
Delegated to: Tom Rini
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Comments

Wolfgang Denk - Nov. 6, 2011, 7:55 p.m.
Downloaded from http://slre.sourceforge.net/
and adapted for U-Boot environment.

Used to implement regex operations on environment variables.
Code size is ~ 3.5 KiB on PPC.

Signed-off-by: Wolfgang Denk <wd@denx.de>
---
Note: This patch was generated on top of my ``env: fix "env ask"
command'' patch. This should be applied before.

 include/slre.h |  100 ++++++++
 lib/slre.c     |  709 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 809 insertions(+), 0 deletions(-)
 create mode 100644 include/slre.h
 create mode 100644 lib/slre.c
Wolfgang Denk - March 22, 2013, 9:44 p.m.
The following patch series adds the SLRE "Super Light Regular
Expression" library and uses this to add regex support for 
the "env grep" (aka "grepenv") command, and new functions (or
operators?) "gsub" and "sub" to the "setexpr" command.

The rework to "env grep" also fixed a few bugs (which cuased it to
dump always _all_ environment varioables on some systems), and adds
the capability to grep in either the variable name, or the value, or
in both (the old version olways did the latter).  Instead of special
functions we now use common code (i. e. hexport_r()) for the variable
lookup, which gives us sorted output as a free additional benefit.

This allows to do things like

- print all MAC addresses:

	=> env grep -e eth.*addr
	eth1addr=00:10:ec:80:c5:15
	ethaddr=00:10:ec:00:c5:15

- print all variables that have at least 2 colons in their value:

	=> env grep -v -e :.*:
	addip=setenv bootargs ${bootargs} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}:${netdev}:off panic=1
	eth1addr=00:10:ec:80:c5:15
	ethaddr=00:10:ec:00:c5:15
	ver=U-Boot 2013.04-rc1-00289-g497746b-dirty (Mar 22 2013 - 12:50:25)

- Generate broadcast address by substituting the last two numbers of
  the IP address by "255.255":

  	=> print ipaddr
	ipaddr=192.168.1.104
	=> setexpr broadcast sub "(.*\\.).*\\..*" "\\1255.255" $ipaddr
	broadcast=192.168.255.255

- Depending on keyboard configuration (German vs. US keyboard) a
  barcode scanner may initialize the MAC address as C0:E5:4E:02:06:DC
  or as C0>E5>4E>02>06>DC.  Make sure we always have a correct value:

  	=> print ethaddr
	ethaddr=C0>E5>4E>02>06>DC
	=> setexpr ethaddr gsub > :
	ethaddr=C0:E5:4E:02:06:DC

etc.

	
Regex support can be enabled by defining  CONFIG_REGEX  in the board
config file.


Wolfgang Denk (9):
  hashtable: preparations to use hexport_r() for "env grep"
  "env grep" - reimplement command using hexport_r()
  "env grep" - add options to grep in name, value, or both.
  Add SLRE - Super Light Regular Expression library
  "env grep" - add support for regular expression matches
  setexpr: simplify code, improve help message
  setexpr: add regex substring matching and substitution
  m28evk: enable "env grep" and regexp support
  amcc-common.h: enable support for "env grep", "setexpr", and regex.

 README                        |   7 +
 common/cmd_nvedit.c           |  87 +++--
 common/cmd_setexpr.c          | 296 ++++++++++++++++-
 include/configs/amcc-common.h |   9 +-
 include/configs/m28evk.h      |   3 +
 include/search.h              |  15 +-
 include/slre.h                | 100 ++++++
 lib/Makefile                  |   1 +
 lib/hashtable.c               |  93 ++++--
 lib/slre.c                    | 724 ++++++++++++++++++++++++++++++++++++++++++
 10 files changed, 1263 insertions(+), 72 deletions(-)
 create mode 100644 include/slre.h
 create mode 100644 lib/slre.c
Wolfgang Denk - March 22, 2013, 9:50 p.m.
Hi,

In message <1363988699-6410-1-git-send-email-wd@denx.de> you wrote:
> The following patch series adds the SLRE "Super Light Regular
> Expression" library and uses this to add regex support for 
> the "env grep" (aka "grepenv") command, and new functions (or
> operators?) "gsub" and "sub" to the "setexpr" command.

I should probably add:

- This patch series has been compile-tested (and found to be clean
  with ELDK v5.3) on all of the following boards:

  ARM: m28evk

  PPC4xx: acadia bamboo bluestone bubinga canyonlands dlvision-10g
  dlvision ebony gdppc440etx icon intip io io64 iocon katmai kilauea
  luan makalu neo ocotea redwood sequoia t3corp taihu taishan walnut
  yosemite yucca

- Runtime / functional testing has been done mostly on PPC (Sequoia
  board).

Best regards,

Wolfgang Denk
Otavio Salvador - March 23, 2013, 12:18 p.m.
On Fri, Mar 22, 2013 at 6:44 PM, Wolfgang Denk <wd@denx.de> wrote:
> The following patch series adds the SLRE "Super Light Regular
> Expression" library and uses this to add regex support for
> the "env grep" (aka "grepenv") command, and new functions (or
> operators?) "gsub" and "sub" to the "setexpr" command.
>
> The rework to "env grep" also fixed a few bugs (which cuased it to
> dump always _all_ environment varioables on some systems), and adds
> the capability to grep in either the variable name, or the value, or
> in both (the old version olways did the latter).  Instead of special
> functions we now use common code (i. e. hexport_r()) for the variable
> lookup, which gives us sorted output as a free additional benefit.

It is awesome :-)

I just found some indenting formating changing in the code mixed with
code change, it'd be good to keep those in specific patches. It is
easy to see in the last patch of serie, for example.

--
Otavio Salvador                             O.S. Systems
E-mail: otavio@ossystems.com.br  http://www.ossystems.com.br
Mobile: +55 53 9981-7854              http://projetos.ossystems.com.br
Wolfgang Denk - March 24, 2013, 9:41 a.m.
Dear Otavio,

In message <CAP9ODKoDSwBRp7sweLwX-7LrQyeHaq0JP1fhe2GJ86E=_ev0fA@mail.gmail.com> you wrote:
>
> > The following patch series adds the SLRE "Super Light Regular
> > Expression" library and uses this to add regex support for
> > the "env grep" (aka "grepenv") command, and new functions (or
> > operators?) "gsub" and "sub" to the "setexpr" command.
...
> It is awesome :-)

I'm glad you like it.

> I just found some indenting formating changing in the code mixed with
> code change, it'd be good to keep those in specific patches. It is
> easy to see in the last patch of serie, for example.

Yes, I will do this.  Thanks!

Best regards,

Wolfgang Denk

Patch

diff --git a/include/slre.h b/include/slre.h
new file mode 100644
index 0000000..4b41a4b
--- /dev/null
+++ b/include/slre.h
@@ -0,0 +1,100 @@ 
+/*
+ * Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
+ * All rights reserved
+ *
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * Sergey Lyubka wrote this file.  As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return.
+ */
+
+/*
+ * Downloaded Sat Nov  5 17:42:08 CET 2011 at
+ * http://slre.sourceforge.net/1.0/slre.h
+ */
+
+/*
+ * This is a regular expression library that implements a subset of Perl RE.
+ * Please refer to http://slre.sourceforge.net for detailed description.
+ *
+ * Usage example (parsing HTTP request):
+ *
+ * struct slre	slre;
+ * struct cap	captures[4 + 1];  // Number of braket pairs + 1
+ * ...
+ *
+ * slre_compile(&slre,"^(GET|POST) (\S+) HTTP/(\S+?)\r\n");
+ *
+ * if (slre_match(&slre, buf, len, captures)) {
+ *	printf("Request line length: %d\n", captures[0].len);
+ *	printf("Method: %.*s\n", captures[1].len, captures[1].ptr);
+ *	printf("URI: %.*s\n", captures[2].len, captures[2].ptr);
+ * }
+ *
+ * Supported syntax:
+ *	^		Match beginning of a buffer
+ *	$		Match end of a buffer
+ *	()		Grouping and substring capturing
+ *	[...]		Match any character from set
+ *	[^...]		Match any character but ones from set
+ *	\s		Match whitespace
+ *	\S		Match non-whitespace
+ *	\d		Match decimal digit
+ *	\r		Match carriage return
+ *	\n		Match newline
+ *	+		Match one or more times (greedy)
+ *	+?		Match one or more times (non-greedy)
+ *	*		Match zero or more times (greedy)
+ *	*?		Match zero or more times (non-greedy)
+ *	?		Match zero or once
+ *	\xDD		Match byte with hex value 0xDD
+ *	\meta		Match one of the meta character: ^$().[*+?\
+ */
+
+#ifndef SLRE_HEADER_DEFINED
+#define	SLRE_HEADER_DEFINED
+
+/*
+ * Compiled regular expression
+ */
+struct slre {
+	unsigned char	code[256];
+	unsigned char	data[256];
+	int		code_size;
+	int		data_size;
+	int		num_caps;	/* Number of bracket pairs	*/
+	int		anchored;	/* Must match from string start	*/
+	const char	*err_str;	/* Error string			*/
+};
+
+/*
+ * Captured substring
+ */
+struct cap {
+	const char	*ptr;		/* Pointer to the substring	*/
+	int		len;		/* Substring length		*/
+};
+
+/*
+ * Compile regular expression. If success, 1 is returned.
+ * If error, 0 is returned and slre.err_str points to the error message.
+ */
+int slre_compile(struct slre *, const char *re);
+
+/*
+ * Return 1 if match, 0 if no match.
+ * If `captured_substrings' array is not NULL, then it is filled with the
+ * values of captured substrings. captured_substrings[0] element is always
+ * a full matched substring. The round bracket captures start from
+ * captured_substrings[1].
+ * It is assumed that the size of captured_substrings array is enough to
+ * hold all captures. The caller function must make sure it is! So, the
+ * array_size = number_of_round_bracket_pairs + 1
+ */
+int slre_match(const struct slre *, const char *buf, int buf_len,
+	struct cap *captured_substrings);
+
+#ifdef SLRE_TEST
+void slre_dump(const struct slre *r, FILE *fp);
+#endif /* SLRE_TEST */
+#endif /* SLRE_HEADER_DEFINED */
diff --git a/lib/slre.c b/lib/slre.c
new file mode 100644
index 0000000..3069c6d
--- /dev/null
+++ b/lib/slre.c
@@ -0,0 +1,709 @@ 
+/*
+ * Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
+ * All rights reserved
+ *
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * Sergey Lyubka wrote this file.  As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return.
+ */
+
+/*
+ * Downloaded Sat Nov  5 17:43:06 CET 2011 at
+ * http://slre.sourceforge.net/1.0/slre.c
+ */
+
+#ifdef SLRE_TEST
+#include <stdio.h>
+#include <assert.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#else
+#include <common.h>
+#include <linux/ctype.h>
+#endif /* SLRE_TEST */
+
+#include <errno.h>
+
+#include <slre.h>
+
+enum {END, BRANCH, ANY, EXACT, ANYOF, ANYBUT, OPEN, CLOSE, BOL, EOL,
+	STAR, PLUS, STARQ, PLUSQ, QUEST, SPACE, NONSPACE, DIGIT};
+
+#ifdef SLRE_TEST
+static struct {
+	const char	*name;
+	int		narg;
+	const char	*flags;
+} opcodes[] = {
+	{"END",		0, ""},		/* End of code block or program	*/
+	{"BRANCH",	2, "oo"},	/* Alternative operator, "|"	*/
+	{"ANY",		0, ""},		/* Match any character, "."	*/
+	{"EXACT",	2, "d"},	/* Match exact string		*/
+	{"ANYOF",	2, "D"},	/* Match any from set, "[]"	*/
+	{"ANYBUT",	2, "D"},	/* Match any but from set, "[^]"*/
+	{"OPEN ",	1, "i"},	/* Capture start, "("		*/
+	{"CLOSE",	1, "i"},	/* Capture end, ")"		*/
+	{"BOL",		0, ""},		/* Beginning of string, "^"	*/
+	{"EOL",		0, ""},		/* End of string, "$"		*/
+	{"STAR",	1, "o"},	/* Match zero or more times "*"	*/
+	{"PLUS",	1, "o"},	/* Match one or more times, "+"	*/
+	{"STARQ",	1, "o"},	/* Non-greedy STAR,  "*?"	*/
+	{"PLUSQ",	1, "o"},	/* Non-greedy PLUS, "+?"	*/
+	{"QUEST",	1, "o"},	/* Match zero or one time, "?"	*/
+	{"SPACE",	0, ""},		/* Match whitespace, "\s"	*/
+	{"NONSPACE",	0, ""},		/* Match non-space, "\S"	*/
+	{"DIGIT",	0, ""}		/* Match digit, "\d"		*/
+};
+#endif /* SLRE_TEST */
+
+/*
+ * Commands and operands are all unsigned char (1 byte long). All code offsets
+ * are relative to current address, and positive (always point forward). Data
+ * offsets are absolute. Commands with operands:
+ *
+ * BRANCH offset1 offset2
+ *	Try to match the code block that follows the BRANCH instruction
+ *	(code block ends with END). If no match, try to match code block that
+ *	starts at offset1. If either of these match, jump to offset2.
+ *
+ * EXACT data_offset data_length
+ *	Try to match exact string. String is recorded in data section from
+ *	data_offset, and has length data_length.
+ *
+ * OPEN capture_number
+ * CLOSE capture_number
+ *	If the user have passed 'struct cap' array for captures, OPEN
+ *	records the beginning of the matched substring (cap->ptr), CLOSE
+ *	sets the length (cap->len) for respective capture_number.
+ *
+ * STAR code_offset
+ * PLUS code_offset
+ * QUEST code_offset
+ *	*, +, ?, respectively. Try to gobble as much as possible from the
+ *	matched buffer, until code block that follows these instructions
+ *	matches. When the longest possible string is matched,
+ *	jump to code_offset
+ *
+ * STARQ, PLUSQ are non-greedy versions of STAR and PLUS.
+ */
+
+static const char *meta_chars = "|.^$*+?()[\\";
+
+#ifdef SLRE_TEST
+
+static void
+print_character_set(FILE *fp, const unsigned char *p, int len)
+{
+	int	i;
+
+	for (i = 0; i < len; i++) {
+		if (i > 0)
+			(void) fputc(',', fp);
+		if (p[i] == 0) {
+			i++;
+			if (p[i] == 0)
+				(void) fprintf(fp, "\\x%02x", p[i]);
+			else
+				(void) fprintf(fp, "%s", opcodes[p[i]].name);
+		} else if (isprint(p[i])) {
+			(void) fputc(p[i], fp);
+		} else {
+			(void) fprintf(fp, "\\x%02x", p[i]);
+		}
+	}
+}
+
+void
+slre_dump(const struct slre *r, FILE *fp)
+{
+	int	i, j, ch, op, pc;
+
+	for (pc = 0; pc < r->code_size; pc++) {
+
+		op = r->code[pc];
+		(void) fprintf(fp, "%3d %s ", pc, opcodes[op].name);
+
+		for (i = 0; opcodes[op].flags[i] != '\0'; i++)
+			switch (opcodes[op].flags[i]) {
+			case 'i':
+				(void) fprintf(fp, "%d ", r->code[pc + 1]);
+				pc++;
+				break;
+			case 'o':
+				(void) fprintf(fp, "%d ",
+				    pc + r->code[pc + 1] - i);
+				pc++;
+				break;
+			case 'D':
+				print_character_set(fp, r->data +
+				    r->code[pc + 1], r->code[pc + 2]);
+				pc += 2;
+				break;
+			case 'd':
+				(void) fputc('"', fp);
+				for (j = 0; j < r->code[pc + 2]; j++) {
+					ch = r->data[r->code[pc + 1] + j];
+					if (isprint(ch)) {
+						(void) fputc(ch, fp);
+					} else {
+						(void) fprintf(fp,
+							"\\x%02x", ch);
+					}
+				}
+				(void) fputc('"', fp);
+				pc += 2;
+				break;
+			}
+
+		(void) fputc('\n', fp);
+	}
+}
+#endif /* SLRE_TEST */
+
+static void
+set_jump_offset(struct slre *r, int pc, int offset)
+{
+	assert(offset < r->code_size);
+
+	if (r->code_size - offset > 0xff)
+		r->err_str = "Jump offset is too big";
+	else
+		r->code[pc] = (unsigned char) (r->code_size - offset);
+}
+
+static void
+emit(struct slre *r, int code)
+{
+	if (r->code_size >= (int) (sizeof(r->code) / sizeof(r->code[0])))
+		r->err_str = "RE is too long (code overflow)";
+	else
+		r->code[r->code_size++] = (unsigned char) code;
+}
+
+static void
+store_char_in_data(struct slre *r, int ch)
+{
+	if (r->data_size >= (int) sizeof(r->data))
+		r->err_str = "RE is too long (data overflow)";
+	else
+		r->data[r->data_size++] = ch;
+}
+
+static void
+exact(struct slre *r, const char **re)
+{
+	int	old_data_size = r->data_size;
+
+	while (**re != '\0' && (strchr(meta_chars, **re)) == NULL)
+		store_char_in_data(r, *(*re)++);
+
+	emit(r, EXACT);
+	emit(r, old_data_size);
+	emit(r, r->data_size - old_data_size);
+}
+
+static int
+get_escape_char(const char **re)
+{
+	int	res;
+
+	switch (*(*re)++) {
+	case 'n':
+		res = '\n';
+		break;
+	case 'r':
+		res = '\r';
+		break;
+	case 't':
+		res = '\t';
+		break;
+	case '0':
+		res = 0;
+		break;
+	case 'S':
+		res = NONSPACE << 8;
+		break;
+	case 's':
+		res = SPACE << 8;
+		break;
+	case 'd':
+		res = DIGIT << 8;
+		break;
+	default:
+		res = (*re)[-1];
+		break;
+	}
+
+	return res;
+}
+
+static void
+anyof(struct slre *r, const char **re)
+{
+	int	esc, old_data_size = r->data_size, op = ANYOF;
+
+	if (**re == '^') {
+		op = ANYBUT;
+		(*re)++;
+	}
+
+	while (**re != '\0')
+
+		switch (*(*re)++) {
+		case ']':
+			emit(r, op);
+			emit(r, old_data_size);
+			emit(r, r->data_size - old_data_size);
+			return;
+			/* NOTREACHED */
+			break;
+		case '\\':
+			esc = get_escape_char(re);
+			if ((esc & 0xff) == 0) {
+				store_char_in_data(r, 0);
+				store_char_in_data(r, esc >> 8);
+			} else {
+				store_char_in_data(r, esc);
+			}
+			break;
+		default:
+			store_char_in_data(r, (*re)[-1]);
+			break;
+		}
+
+	r->err_str = "No closing ']' bracket";
+}
+
+static void
+relocate(struct slre *r, int begin, int shift)
+{
+	emit(r, END);
+	memmove(r->code + begin + shift, r->code + begin, r->code_size - begin);
+	r->code_size += shift;
+}
+
+static void
+quantifier(struct slre *r, int prev, int op)
+{
+	if (r->code[prev] == EXACT && r->code[prev + 2] > 1) {
+		r->code[prev + 2]--;
+		emit(r, EXACT);
+		emit(r, r->code[prev + 1] + r->code[prev + 2]);
+		emit(r, 1);
+		prev = r->code_size - 3;
+	}
+	relocate(r, prev, 2);
+	r->code[prev] = op;
+	set_jump_offset(r, prev + 1, prev);
+}
+
+static void
+exact_one_char(struct slre *r, int ch)
+{
+	emit(r, EXACT);
+	emit(r, r->data_size);
+	emit(r, 1);
+	store_char_in_data(r, ch);
+}
+
+static void
+fixup_branch(struct slre *r, int fixup)
+{
+	if (fixup > 0) {
+		emit(r, END);
+		set_jump_offset(r, fixup, fixup - 2);
+	}
+}
+
+static void
+compile(struct slre *r, const char **re)
+{
+	int	op, esc, branch_start, last_op, fixup, cap_no, level;
+
+	fixup = 0;
+	level = r->num_caps;
+	branch_start = last_op = r->code_size;
+
+	for (;;)
+		switch (*(*re)++) {
+		case '\0':
+			(*re)--;
+			return;
+			/* NOTREACHED */
+			break;
+		case '^':
+			emit(r, BOL);
+			break;
+		case '$':
+			emit(r, EOL);
+			break;
+		case '.':
+			last_op = r->code_size;
+			emit(r, ANY);
+			break;
+		case '[':
+			last_op = r->code_size;
+			anyof(r, re);
+			break;
+		case '\\':
+			last_op = r->code_size;
+			esc = get_escape_char(re);
+			if (esc & 0xff00)
+				emit(r, esc >> 8);
+			else
+				exact_one_char(r, esc);
+			break;
+		case '(':
+			last_op = r->code_size;
+			cap_no = ++r->num_caps;
+			emit(r, OPEN);
+			emit(r, cap_no);
+
+			compile(r, re);
+			if (*(*re)++ != ')') {
+				r->err_str = "No closing bracket";
+				return;
+			}
+
+			emit(r, CLOSE);
+			emit(r, cap_no);
+			break;
+		case ')':
+			(*re)--;
+			fixup_branch(r, fixup);
+			if (level == 0) {
+				r->err_str = "Unbalanced brackets";
+				return;
+			}
+			return;
+			/* NOTREACHED */
+			break;
+		case '+':
+		case '*':
+			op = (*re)[-1] == '*' ? STAR : PLUS;
+			if (**re == '?') {
+				(*re)++;
+				op = op == STAR ? STARQ : PLUSQ;
+			}
+			quantifier(r, last_op, op);
+			break;
+		case '?':
+			quantifier(r, last_op, QUEST);
+			break;
+		case '|':
+			fixup_branch(r, fixup);
+			relocate(r, branch_start, 3);
+			r->code[branch_start] = BRANCH;
+			set_jump_offset(r, branch_start + 1, branch_start);
+			fixup = branch_start + 2;
+			r->code[fixup] = 0xff;
+			break;
+		default:
+			(*re)--;
+			last_op = r->code_size;
+			exact(r, re);
+			break;
+		}
+}
+
+int
+slre_compile(struct slre *r, const char *re)
+{
+	r->err_str = NULL;
+	r->code_size = r->data_size = r->num_caps = r->anchored = 0;
+
+	if (*re == '^')
+		r->anchored++;
+
+	emit(r, OPEN);	/* This will capture what matches full RE */
+	emit(r, 0);
+
+	while (*re != '\0')
+		compile(r, &re);
+
+	if (r->code[2] == BRANCH)
+		fixup_branch(r, 4);
+
+	emit(r, CLOSE);
+	emit(r, 0);
+	emit(r, END);
+
+	return (r->err_str == NULL ? 1 : 0);
+}
+
+static int match(const struct slre *, int,
+		const char *, int, int *, struct cap *);
+
+static void
+loop_greedy(const struct slre *r, int pc, const char *s, int len, int *ofs)
+{
+	int	saved_offset, matched_offset;
+
+	saved_offset = matched_offset = *ofs;
+
+	while (match(r, pc + 2, s, len, ofs, NULL)) {
+		saved_offset = *ofs;
+		if (match(r, pc + r->code[pc + 1], s, len, ofs, NULL))
+			matched_offset = saved_offset;
+		*ofs = saved_offset;
+	}
+
+	*ofs = matched_offset;
+}
+
+static void
+loop_non_greedy(const struct slre *r, int pc, const char *s, int len, int *ofs)
+{
+	int	saved_offset = *ofs;
+
+	while (match(r, pc + 2, s, len, ofs, NULL)) {
+		saved_offset = *ofs;
+		if (match(r, pc + r->code[pc + 1], s, len, ofs, NULL))
+			break;
+	}
+
+	*ofs = saved_offset;
+}
+
+static int
+is_any_of(const unsigned char *p, int len, const char *s, int *ofs)
+{
+	int	i, ch;
+
+	ch = s[*ofs];
+
+	for (i = 0; i < len; i++)
+		if (p[i] == ch) {
+			(*ofs)++;
+			return 1;
+		}
+
+	return 0;
+}
+
+static int
+is_any_but(const unsigned char *p, int len, const char *s, int *ofs)
+{
+	int	i, ch;
+
+	ch = s[*ofs];
+
+	for (i = 0; i < len; i++) {
+		if (p[i] == ch)
+			return 0;
+	}
+
+	(*ofs)++;
+	return 1;
+}
+
+static int
+match(const struct slre *r, int pc, const char *s, int len,
+		int *ofs, struct cap *caps)
+{
+	int	n, saved_offset, res = 1;
+
+	while (res && r->code[pc] != END) {
+
+		assert(pc < r->code_size);
+		assert(pc < (int) (sizeof(r->code) / sizeof(r->code[0])));
+
+		switch (r->code[pc]) {
+		case BRANCH:
+			saved_offset = *ofs;
+			res = match(r, pc + 3, s, len, ofs, caps);
+			if (res == 0) {
+				*ofs = saved_offset;
+				res = match(r, pc + r->code[pc + 1],
+				    s, len, ofs, caps);
+			}
+			pc += r->code[pc + 2];
+			break;
+		case EXACT:
+			res = 0;
+			n = r->code[pc + 2];	/* String length */
+			if (n <= len - *ofs && !memcmp(s + *ofs, r->data +
+			    r->code[pc + 1], n)) {
+				(*ofs) += n;
+				res = 1;
+			}
+			pc += 3;
+			break;
+		case QUEST:
+			res = 1;
+			saved_offset = *ofs;
+			if (!match(r, pc + 2, s, len, ofs, caps))
+				*ofs = saved_offset;
+			pc += r->code[pc + 1];
+			break;
+		case STAR:
+			res = 1;
+			loop_greedy(r, pc, s, len, ofs);
+			pc += r->code[pc + 1];
+			break;
+		case STARQ:
+			res = 1;
+			loop_non_greedy(r, pc, s, len, ofs);
+			pc += r->code[pc + 1];
+			break;
+		case PLUS:
+			res = match(r, pc + 2, s, len, ofs, caps);
+			if (res == 0)
+				break;
+
+			loop_greedy(r, pc, s, len, ofs);
+			pc += r->code[pc + 1];
+			break;
+		case PLUSQ:
+			res = match(r, pc + 2, s, len, ofs, caps);
+			if (res == 0)
+				break;
+
+			loop_non_greedy(r, pc, s, len, ofs);
+			pc += r->code[pc + 1];
+			break;
+		case SPACE:
+			res = 0;
+			if (*ofs < len && isspace(((unsigned char *)s)[*ofs])) {
+				(*ofs)++;
+				res = 1;
+			}
+			pc++;
+			break;
+		case NONSPACE:
+			res = 0;
+			if (*ofs < len &&
+					!isspace(((unsigned char *)s)[*ofs])) {
+				(*ofs)++;
+				res = 1;
+			}
+			pc++;
+			break;
+		case DIGIT:
+			res = 0;
+			if (*ofs < len && isdigit(((unsigned char *)s)[*ofs])) {
+				(*ofs)++;
+				res = 1;
+			}
+			pc++;
+			break;
+		case ANY:
+			res = 0;
+			if (*ofs < len) {
+				(*ofs)++;
+				res = 1;
+			}
+			pc++;
+			break;
+		case ANYOF:
+			res = 0;
+			if (*ofs < len)
+				res = is_any_of(r->data + r->code[pc + 1],
+					r->code[pc + 2], s, ofs);
+			pc += 3;
+			break;
+		case ANYBUT:
+			res = 0;
+			if (*ofs < len)
+				res = is_any_but(r->data + r->code[pc + 1],
+					r->code[pc + 2], s, ofs);
+			pc += 3;
+			break;
+		case BOL:
+			res = *ofs == 0 ? 1 : 0;
+			pc++;
+			break;
+		case EOL:
+			res = *ofs == len ? 1 : 0;
+			pc++;
+			break;
+		case OPEN:
+			if (caps != NULL)
+				caps[r->code[pc + 1]].ptr = s + *ofs;
+			pc += 2;
+			break;
+		case CLOSE:
+			if (caps != NULL)
+				caps[r->code[pc + 1]].len = (s + *ofs) -
+				    caps[r->code[pc + 1]].ptr;
+			pc += 2;
+			break;
+		case END:
+			pc++;
+			break;
+		default:
+			printf("unknown cmd (%d) at %d\n", r->code[pc], pc);
+			assert(0);
+			break;
+		}
+	}
+
+	return res;
+}
+
+int
+slre_match(const struct slre *r, const char *buf, int len,
+		struct cap *caps)
+{
+	int	i, ofs = 0, res = 0;
+
+	if (r->anchored) {
+		res = match(r, 0, buf, len, &ofs, caps);
+	} else {
+		for (i = 0; i < len && res == 0; i++) {
+			ofs = i;
+			res = match(r, 0, buf, len, &ofs, caps);
+		}
+	}
+
+	return res;
+}
+
+#ifdef SLRE_TEST
+int main(int argc, char *argv[])
+{
+	struct slre	slre;
+	struct cap	caps[20];
+	char		data[1 * 1024 * 1024];
+	FILE		*fp;
+	int		i, count, res, len;
+
+	if (argc < 3) {
+		printf("Usage: %s 'slre' <file> [count]\n", argv[0]);
+	} else {
+		fp = fopen(argv[2], "rb");
+		if (fp == NULL) {
+			printf("Error: cannot open %s:%s\n",
+				argv[2], strerror(errno));
+		} else if (!slre_compile(&slre, argv[1])) {
+			printf("Error compiling slre: %s\n", slre.err_str);
+		} else {
+			slre_dump(&slre, stderr);
+
+			(void) memset(caps, 0, sizeof(caps));
+
+			/* Read first 128K of file */
+			len = fread(data, 1, sizeof(data), fp);
+			(void) fclose(fp);
+
+			res = 0;
+			count = argc > 3 ? atoi(argv[3]) : 1;
+			for (i = 0; i < count; i++)
+				res = slre_match(&slre, data, len, caps);
+
+			printf("Result: %d\n", res);
+
+			for (i = 0; i < 20; i++) {
+				if (caps[i].len > 0) {
+					printf("Substring %d: [%.*s]\n", i,
+						caps[i].len, caps[i].ptr);
+				}
+			}
+		}
+	}
+
+	return 0;
+}
+#endif /* SLRE_TEST */