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

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 */