summaryrefslogtreecommitdiff
path: root/lib/slre.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/slre.c')
-rw-r--r--lib/slre.c724
1 files changed, 724 insertions, 0 deletions
diff --git a/lib/slre.c b/lib/slre.c
new file mode 100644
index 0000000..8cdd192
--- /dev/null
+++ b/lib/slre.c
@@ -0,0 +1,724 @@
+/*
+ * 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
+#define N_CAPS 5
+
+int main(int argc, char *argv[])
+{
+ struct slre slre;
+ struct cap caps[N_CAPS];
+ unsigned char data[1 * 1024 * 1024];
+ FILE *fp;
+ int i, res, len;
+
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s 'slre' <file>\n", argv[0]);
+ return 1;
+ }
+
+ fp = fopen(argv[2], "rb");
+ if (fp == NULL) {
+ fprintf(stderr, "Error: cannot open %s:%s\n",
+ argv[2], strerror(errno));
+ return 1;
+ }
+
+ if (!slre_compile(&slre, argv[1])) {
+ fprintf(stderr, "Error compiling slre: %s\n", slre.err_str);
+ return 1;
+ }
+
+ slre_dump(&slre, stderr);
+
+ while (fgets(data, sizeof(data), fp) != NULL) {
+ len = strlen(data);
+
+ if ((len > 0) && (data[len-1] == '\n')) {
+ data[len-1] = '\0';
+ --len;
+ }
+
+ printf("Data = \"%s\"\n", data);
+
+ (void) memset(caps, 0, sizeof(caps));
+
+ res = 0;
+
+ res = slre_match(&slre, data, len, caps);
+ printf("Result [%d]: %d\n", i, res);
+
+ for (i = 0; i < N_CAPS; i++) {
+ if (caps[i].len > 0) {
+ printf("Substring %d: len=%d [%.*s]\n", i,
+ caps[i].len,
+ caps[i].len, caps[i].ptr);
+ }
+ }
+ printf("----------------------------------------------------\n");
+ }
+ (void) fclose(fp);
+
+ return 0;
+}
+#endif /* SLRE_TEST */
generated by cgit v1.1 at 2024-11-19 05:06:36 +0000