Paul Eggert wrote:
> > Paul, Jim: Would it be OK to move them to a Gnulib module?
>
> Sounds good to me.
Done through these three patches.
In the third patch, while writing a unit test, I noticed that the
documentation of kwsexec() was misleading, and corrected that.
2025-06-25 Bruno Haible <br...@clisp.org>
kwset: Add tests.
* lib/kwset.c (kwsexec): Correct documentation.
* tests/test-kwset.c: New file.
* modules/kwset-tests: New file.
kwset: Usability tweaks.
* lib/kwset.h: Make header idempotent and C++ safe. Check that config.h
was already included.
kwset: New module.
* lib/kwset.h: New file, from GNU grep.
* lib/kwset.c: New file, from GNU grep.
Include <limits.h>, minmax.h. Don't include system.h.
(IGNORE_DUPLICATE_BRANCH_WARNING): New macro, from grep/src/system.h.
(NCHAR): New enum value, from grep/src/system.h.
(to_uchar): New function, from grep/src/system.h.
* modules/kwset: New file.
>From 1ff1804ab96d5ffad94e5cf62f956e6e54f6ae64 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Wed, 25 Jun 2025 14:24:41 +0200
Subject: [PATCH 1/3] kwset: New module.
* lib/kwset.h: New file, from GNU grep.
* lib/kwset.c: New file, from GNU grep.
Include <limits.h>, minmax.h. Don't include system.h.
(IGNORE_DUPLICATE_BRANCH_WARNING): New macro, from grep/src/system.h.
(NCHAR): New enum value, from grep/src/system.h.
(to_uchar): New function, from grep/src/system.h.
* modules/kwset: New file.
---
ChangeLog | 11 +
lib/kwset.c | 936 ++++++++++++++++++++++++++++++++++++++++++++++++++
lib/kwset.h | 44 +++
modules/kwset | 33 ++
4 files changed, 1024 insertions(+)
create mode 100644 lib/kwset.c
create mode 100644 lib/kwset.h
create mode 100644 modules/kwset
diff --git a/ChangeLog b/ChangeLog
index 7774a22b3a..c9c4485672 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2025-06-25 Bruno Haible <br...@clisp.org>
+
+ kwset: New module.
+ * lib/kwset.h: New file, from GNU grep.
+ * lib/kwset.c: New file, from GNU grep.
+ Include <limits.h>, minmax.h. Don't include system.h.
+ (IGNORE_DUPLICATE_BRANCH_WARNING): New macro, from grep/src/system.h.
+ (NCHAR): New enum value, from grep/src/system.h.
+ (to_uchar): New function, from grep/src/system.h.
+ * modules/kwset: New file.
+
2025-06-24 Paul Eggert <egg...@cs.ucla.edu>
Sort-of sync model bootstrap.conf from coreutils
diff --git a/lib/kwset.c b/lib/kwset.c
new file mode 100644
index 0000000000..5a3b9c9919
--- /dev/null
+++ b/lib/kwset.c
@@ -0,0 +1,936 @@
+/* kwset.c - search for any of a set of keywords.
+ Copyright (C) 1989, 1998, 2000, 2005, 2007, 2009-2025 Free Software
+ Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written August 1989 by Mike Haertel. */
+
+/* For more on the Aho-Corasick and Boyer-Moore algorithms,
+ as well as other algorithms that might help improve performance,
+ see the grep manual's "Performance" chapter. */
+
+#include <config.h>
+
+#include "kwset.h"
+
+#include <limits.h>
+#include <stdckdint.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#include "memchr2.h"
+#include "minmax.h"
+#include "obstack.h"
+#include "xalloc.h"
+#include "verify.h"
+
+#define obstack_chunk_alloc xmalloc
+#define obstack_chunk_free free
+
+/* When we deliberately use duplicate branches, use this macro to
+ disable gcc's -Wduplicated-branches in the containing expression. */
+#if 7 <= __GNUC__
+# define IGNORE_DUPLICATE_BRANCH_WARNING(exp) \
+ ({ \
+ _Pragma ("GCC diagnostic push") \
+ _Pragma ("GCC diagnostic ignored \"-Wduplicated-branches\"") \
+ exp; \
+ _Pragma ("GCC diagnostic pop") \
+ })
+#else
+# define IGNORE_DUPLICATE_BRANCH_WARNING(exp) exp
+#endif
+
+enum { NCHAR = UCHAR_MAX + 1 };
+
+/* Convert a possibly-signed character to an unsigned character. This is
+ a bit safer than casting to unsigned char, since it catches some type
+ errors that the cast doesn't. */
+static inline unsigned char
+to_uchar (char ch)
+{
+ return ch;
+}
+
+static unsigned char
+U (char ch)
+{
+ return to_uchar (ch);
+}
+
+/* Balanced tree of edges and labels leaving a given trie node. */
+struct tree
+{
+ struct tree *llink; /* Left link; MUST be first field. */
+ struct tree *rlink; /* Right link (to larger labels). */
+ struct trie *trie; /* Trie node pointed to by this edge. */
+ unsigned char label; /* Label on this edge. */
+ char balance; /* Difference in depths of subtrees. */
+};
+
+/* Node of a trie representing a set of keywords. */
+struct trie
+{
+ /* If an accepting node, this is either 2*W + 1 where W is the word
+ index, or is -1 if Aho-Corasick is in use and FAIL
+ specifies where to look for more info. If not an accepting node,
+ this is zero. */
+ ptrdiff_t accepting;
+
+ struct tree *links; /* Tree of edges leaving this node. */
+ struct trie *parent; /* Parent of this node. */
+ struct trie *next; /* List of all trie nodes in level order. */
+ struct trie *fail; /* Aho-Corasick failure function. */
+ idx_t depth; /* Depth of this node from the root. */
+ idx_t shift; /* Shift function for search failures. */
+ idx_t maxshift; /* Max shift of self and descendants. */
+};
+
+/* Structure returned opaquely to the caller, containing everything. */
+struct kwset
+{
+ struct obstack obstack; /* Obstack for node allocation. */
+ idx_t words; /* Number of words in the trie. */
+ struct trie *trie; /* The trie itself. */
+ idx_t mind; /* Minimum depth of an accepting node. */
+ unsigned char delta[NCHAR]; /* Delta table for rapid search. */
+ struct trie *next[NCHAR]; /* Table of children of the root. */
+ char *target; /* Target string if there's only one. */
+ idx_t *shift; /* Used in Boyer-Moore search for one
+ string. */
+ char const *trans; /* Character translation table. */
+
+ /* This helps to match a terminal byte, which is the first byte
+ for Aho-Corasick, and the last byte for Boyer-More. If all the
+ patterns have the same terminal byte (after translation via TRANS
+ if TRANS is nonnull), then this is that byte as an unsigned char.
+ Otherwise this is -1 if there is disagreement among the strings
+ about terminal bytes, and -2 if there are no terminal bytes and
+ no disagreement because all the patterns are empty. */
+ int gc1;
+
+ /* This helps to match a terminal byte. If 0 <= GC1HELP, B is
+ terminal when B == GC1 || B == GC1HELP (note that GC1 == GCHELP
+ is common here). This is typically faster than evaluating
+ to_uchar (TRANS[B]) == GC1. */
+ int gc1help;
+
+ /* If the string has two or more bytes, this is the penultimate byte,
+ after translation via TRANS if TRANS is nonnull. This variable
+ is used only by Boyer-Moore. */
+ char gc2;
+
+ /* kwsexec implementation. */
+ ptrdiff_t (*kwsexec) (kwset_t, char const *, idx_t, struct kwsmatch *, bool);
+};
+
+/* Use TRANS to transliterate C. A null TRANS does no transliteration. */
+static inline char
+tr (char const *trans, char c)
+{
+ return trans ? trans[U(c)] : c;
+}
+
+static ptrdiff_t acexec (kwset_t, char const *, idx_t,
+ struct kwsmatch *, bool);
+static ptrdiff_t bmexec (kwset_t, char const *, idx_t,
+ struct kwsmatch *, bool);
+
+/* Return a newly allocated keyword set. A nonnull TRANS specifies a
+ table of character translations to be applied to all pattern and
+ search text. */
+kwset_t
+kwsalloc (char const *trans)
+{
+ struct kwset *kwset = xmalloc (sizeof *kwset);
+
+ obstack_init (&kwset->obstack);
+ kwset->words = 0;
+ kwset->trie = obstack_alloc (&kwset->obstack, sizeof *kwset->trie);
+ kwset->trie->accepting = 0;
+ kwset->trie->links = nullptr;
+ kwset->trie->parent = nullptr;
+ kwset->trie->next = nullptr;
+ kwset->trie->fail = nullptr;
+ kwset->trie->depth = 0;
+ kwset->trie->shift = 0;
+ kwset->mind = IDX_MAX;
+ kwset->target = nullptr;
+ kwset->trans = trans;
+ kwset->kwsexec = acexec;
+
+ return kwset;
+}
+
+/* This upper bound is valid for CHAR_BIT >= 4 and
+ exact for CHAR_BIT in { 4..11, 13, 15, 17, 19 }. */
+enum { DEPTH_SIZE = CHAR_BIT + CHAR_BIT / 2 };
+
+/* Add the given string to the contents of the keyword set. */
+void
+kwsincr (kwset_t kwset, char const *text, idx_t len)
+{
+ assume (0 <= len);
+ struct trie *trie = kwset->trie;
+ char const *trans = kwset->trans;
+ bool reverse = kwset->kwsexec == bmexec;
+
+ if (reverse)
+ text += len;
+
+ /* Descend the trie (built of keywords) character-by-character,
+ installing new nodes when necessary. */
+ while (len--)
+ {
+ unsigned char uc = reverse ? *--text : *text++;
+ unsigned char label = trans ? trans[uc] : uc;
+
+ /* Descend the tree of outgoing links for this trie node,
+ looking for the current character and keeping track
+ of the path followed. */
+ struct tree *cur = trie->links;
+ struct tree *links[DEPTH_SIZE];
+ enum { L, R } dirs[DEPTH_SIZE];
+ links[0] = (struct tree *) &trie->links;
+ dirs[0] = L;
+ idx_t depth = 1;
+
+ while (cur && label != cur->label)
+ {
+ links[depth] = cur;
+ if (label < cur->label)
+ dirs[depth++] = L, cur = cur->llink;
+ else
+ dirs[depth++] = R, cur = cur->rlink;
+ }
+
+ /* The current character doesn't have an outgoing link at
+ this trie node, so build a new trie node and install
+ a link in the current trie node's tree. */
+ if (!cur)
+ {
+ cur = obstack_alloc (&kwset->obstack, sizeof *cur);
+ cur->llink = nullptr;
+ cur->rlink = nullptr;
+ cur->trie = obstack_alloc (&kwset->obstack, sizeof *cur->trie);
+ cur->trie->accepting = 0;
+ cur->trie->links = nullptr;
+ cur->trie->parent = trie;
+ cur->trie->next = nullptr;
+ cur->trie->fail = nullptr;
+ cur->trie->depth = trie->depth + 1;
+ cur->trie->shift = 0;
+ cur->label = label;
+ cur->balance = 0;
+
+ /* Install the new tree node in its parent. */
+ if (dirs[--depth] == L)
+ links[depth]->llink = cur;
+ else
+ links[depth]->rlink = cur;
+
+ /* Back up the tree fixing the balance flags. */
+ while (depth && !links[depth]->balance)
+ {
+ if (dirs[depth] == L)
+ --links[depth]->balance;
+ else
+ ++links[depth]->balance;
+ --depth;
+ }
+
+ /* Rebalance the tree by pointer rotations if necessary. */
+ if (depth && ((dirs[depth] == L && --links[depth]->balance)
+ || (dirs[depth] == R && ++links[depth]->balance)))
+ {
+ struct tree *t, *r, *l, *rl, *lr;
+
+ switch (links[depth]->balance)
+ {
+ case (char) -2:
+ switch (dirs[depth + 1])
+ {
+ case L:
+ r = links[depth], t = r->llink, rl = t->rlink;
+ t->rlink = r, r->llink = rl;
+ t->balance = r->balance = 0;
+ break;
+ case R:
+ r = links[depth], l = r->llink, t = l->rlink;
+ rl = t->rlink, lr = t->llink;
+ t->llink = l, l->rlink = lr, t->rlink = r, r->llink = rl;
+ l->balance = t->balance != 1 ? 0 : -1;
+ r->balance = t->balance != (char) -1 ? 0 : 1;
+ t->balance = 0;
+ break;
+ default:
+ abort ();
+ }
+ break;
+ case 2:
+ switch (dirs[depth + 1])
+ {
+ case R:
+ l = links[depth], t = l->rlink, lr = t->llink;
+ t->llink = l, l->rlink = lr;
+ t->balance = l->balance = 0;
+ break;
+ case L:
+ l = links[depth], r = l->rlink, t = r->llink;
+ lr = t->llink, rl = t->rlink;
+ t->llink = l, l->rlink = lr, t->rlink = r, r->llink = rl;
+ l->balance = t->balance != 1 ? 0 : -1;
+ r->balance = t->balance != (char) -1 ? 0 : 1;
+ t->balance = 0;
+ break;
+ default:
+ abort ();
+ }
+ break;
+ default:
+ abort ();
+ }
+
+ if (dirs[depth - 1] == L)
+ links[depth - 1]->llink = t;
+ else
+ links[depth - 1]->rlink = t;
+ }
+ }
+
+ trie = cur->trie;
+ }
+
+ /* Mark the node finally reached as accepting, encoding the
+ index number of this word in the keyword set so far. */
+ if (!trie->accepting)
+ trie->accepting = 2 * kwset->words + 1;
+ ++kwset->words;
+
+ /* Keep track of the longest and shortest string of the keyword set. */
+ if (trie->depth < kwset->mind)
+ kwset->mind = trie->depth;
+}
+
+idx_t
+kwswords (kwset_t kwset)
+{
+ return kwset->words;
+}
+
+/* Enqueue the trie nodes referenced from the given tree in the
+ given queue. */
+static void
+enqueue (struct tree *tree, struct trie **last)
+{
+ if (!tree)
+ return;
+ enqueue (tree->llink, last);
+ enqueue (tree->rlink, last);
+ (*last) = (*last)->next = tree->trie;
+}
+
+/* Compute the Aho-Corasick failure function for the trie nodes referenced
+ from the given tree, given the failure function for their parent as
+ well as a last resort failure node. */
+static void
+treefails (struct tree const *tree, struct trie const *fail,
+ struct trie *recourse, bool reverse)
+{
+ struct tree *cur;
+
+ if (!tree)
+ return;
+
+ treefails (tree->llink, fail, recourse, reverse);
+ treefails (tree->rlink, fail, recourse, reverse);
+
+ /* Find, in the chain of fails going back to the root, the first
+ node that has a descendant on the current label. */
+ while (fail)
+ {
+ cur = fail->links;
+ while (cur && tree->label != cur->label)
+ if (tree->label < cur->label)
+ cur = cur->llink;
+ else
+ cur = cur->rlink;
+ if (cur)
+ {
+ tree->trie->fail = cur->trie;
+ if (!reverse && cur->trie->accepting && !tree->trie->accepting)
+ tree->trie->accepting = -1;
+ return;
+ }
+ fail = fail->fail;
+ }
+
+ tree->trie->fail = recourse;
+}
+
+/* Set delta entries for the links of the given tree such that
+ the preexisting delta value is larger than the current depth. */
+static void
+treedelta (struct tree const *tree, idx_t depth, unsigned char delta[])
+{
+ if (!tree)
+ return;
+ treedelta (tree->llink, depth, delta);
+ treedelta (tree->rlink, depth, delta);
+ if (depth < delta[tree->label])
+ delta[tree->label] = depth;
+}
+
+/* Return true if A has every label in B. */
+static bool _GL_ATTRIBUTE_PURE
+hasevery (struct tree const *a, struct tree const *b)
+{
+ if (!b)
+ return true;
+ if (!hasevery (a, b->llink))
+ return false;
+ if (!hasevery (a, b->rlink))
+ return false;
+ while (a && b->label != a->label)
+ if (b->label < a->label)
+ a = a->llink;
+ else
+ a = a->rlink;
+ return !!a;
+}
+
+/* Compute a vector, indexed by character code, of the trie nodes
+ referenced from the given tree. */
+static void
+treenext (struct tree const *tree, struct trie *next[])
+{
+ if (!tree)
+ return;
+ treenext (tree->llink, next);
+ treenext (tree->rlink, next);
+ next[tree->label] = tree->trie;
+}
+
+/* Prepare a built keyword set for use. */
+void
+kwsprep (kwset_t kwset)
+{
+ char const *trans = kwset->trans;
+ unsigned char deltabuf[NCHAR];
+ unsigned char *delta = trans ? deltabuf : kwset->delta;
+ struct trie *curr, *last;
+
+ /* Use Boyer-Moore if just one pattern, Aho-Corasick otherwise. */
+ bool reverse = kwset->words == 1;
+
+ if (reverse)
+ {
+ kwset_t new_kwset;
+
+ /* Enqueue the immediate descendants in the level order queue. */
+ for (curr = last = kwset->trie; curr; curr = curr->next)
+ enqueue (curr->links, &last);
+
+ /* Looking for just one string. Extract it from the trie. */
+ kwset->target = obstack_alloc (&kwset->obstack, kwset->mind);
+ curr = kwset->trie;
+ for (idx_t i = 0; i < kwset->mind; i++)
+ {
+ kwset->target[i] = curr->links->label;
+ curr = curr->next;
+ }
+
+ new_kwset = kwsalloc (kwset->trans);
+ new_kwset->kwsexec = bmexec;
+ kwsincr (new_kwset, kwset->target, kwset->mind);
+ obstack_free (&kwset->obstack, nullptr);
+ *kwset = *new_kwset;
+ free (new_kwset);
+ }
+
+ /* Initial values for the delta table; will be changed later. The
+ delta entry for a given character is the smallest depth of any
+ node at which an outgoing edge is labeled by that character. */
+ memset (delta, MIN (kwset->mind, UCHAR_MAX), sizeof deltabuf);
+
+ /* Traverse the nodes of the trie in level order, simultaneously
+ computing the delta table, failure function, and shift function. */
+ for (curr = last = kwset->trie; curr; curr = curr->next)
+ {
+ /* Enqueue the immediate descendants in the level order queue. */
+ enqueue (curr->links, &last);
+
+ /* Update the delta table for the descendants of this node. */
+ treedelta (curr->links, curr->depth, delta);
+
+ /* Compute the failure function for the descendants of this node. */
+ treefails (curr->links, curr->fail, kwset->trie, reverse);
+
+ if (reverse)
+ {
+ curr->shift = kwset->mind;
+ curr->maxshift = kwset->mind;
+
+ /* Update the shifts at each node in the current node's chain
+ of fails back to the root. */
+ struct trie *fail;
+ for (fail = curr->fail; fail; fail = fail->fail)
+ {
+ /* If the current node has some outgoing edge that the fail
+ doesn't, then the shift at the fail should be no larger
+ than the difference of their depths. */
+ if (!hasevery (fail->links, curr->links))
+ if (curr->depth - fail->depth < fail->shift)
+ fail->shift = curr->depth - fail->depth;
+
+ /* If the current node is accepting then the shift at the
+ fail and its descendants should be no larger than the
+ difference of their depths. */
+ if (curr->accepting && fail->maxshift > curr->depth - fail->depth)
+ fail->maxshift = curr->depth - fail->depth;
+ }
+ }
+ }
+
+ if (reverse)
+ {
+ /* Traverse the trie in level order again, fixing up all nodes whose
+ shift exceeds their inherited maxshift. */
+ for (curr = kwset->trie->next; curr; curr = curr->next)
+ {
+ if (curr->maxshift > curr->parent->maxshift)
+ curr->maxshift = curr->parent->maxshift;
+ if (curr->shift > curr->maxshift)
+ curr->shift = curr->maxshift;
+ }
+ }
+
+ /* Create a vector, indexed by character code, of the outgoing links
+ from the root node. Accumulate GC1 and GC1HELP. */
+ struct trie *nextbuf[NCHAR];
+ struct trie **next = trans ? nextbuf : kwset->next;
+ memset (next, 0, sizeof nextbuf);
+ treenext (kwset->trie->links, next);
+ int gc1 = -2;
+ int gc1help = -1;
+ for (int i = 0; i < NCHAR; i++)
+ {
+ int ti = i;
+ if (trans)
+ {
+ ti = U(trans[i]);
+ kwset->next[i] = next[ti];
+ }
+ if (kwset->next[i])
+ {
+ if (gc1 < -1)
+ {
+ gc1 = ti;
+ gc1help = i;
+ }
+ else if (gc1 == ti)
+ gc1help = gc1help == ti ? i : -1;
+ else if (i == ti && gc1 == gc1help)
+ gc1help = i;
+ else
+ gc1 = -1;
+ }
+ }
+ kwset->gc1 = gc1;
+ kwset->gc1help = gc1help;
+
+ if (reverse)
+ {
+ /* Looking for just one string. Extract it from the trie. */
+ kwset->target = obstack_alloc (&kwset->obstack, kwset->mind);
+ curr = kwset->trie;
+ for (idx_t i = kwset->mind; 0 < i; i--)
+ {
+ kwset->target[i - 1] = curr->links->label;
+ curr = curr->next;
+ }
+
+ if (kwset->mind > 1)
+ {
+ /* Looking for the delta2 shift that might be made after a
+ backwards match has failed. Extract it from the trie. */
+ kwset->shift
+ = obstack_alloc (&kwset->obstack,
+ sizeof *kwset->shift * (kwset->mind - 1));
+ curr = kwset->trie->next;
+ for (idx_t i = 0; i < kwset->mind - 1; i++)
+ {
+ kwset->shift[i] = curr->shift;
+ curr = curr->next;
+ }
+
+ /* The penultimate byte. */
+ kwset->gc2 = tr (trans, kwset->target[kwset->mind - 2]);
+ }
+ }
+
+ /* Fix things up for any translation table. */
+ if (trans)
+ for (int i = 0; i < NCHAR; ++i)
+ kwset->delta[i] = delta[U(trans[i])];
+}
+
+/* Delta2 portion of a Boyer-Moore search. *TP is the string text
+ pointer; it is updated in place. EP is the end of the string text,
+ and SP the end of the pattern. LEN is the pattern length; it must
+ be at least 2. TRANS, if nonnull, is the input translation table.
+ GC1 and GC2 are the last and second-from last bytes of the pattern,
+ transliterated by TRANS; the caller precomputes them for
+ efficiency. If D1 is nonnull, it is a delta1 table for shifting *TP
+ when failing. KWSET->shift says how much to shift. */
+static inline bool
+bm_delta2_search (char const **tpp, char const *ep, char const *sp,
+ idx_t len,
+ char const *trans, char gc1, char gc2,
+ unsigned char const *d1, kwset_t kwset)
+{
+ char const *tp = *tpp;
+ idx_t d = len, skip = 0;
+
+ while (true)
+ {
+ idx_t i = 2;
+ if (tr (trans, tp[-2]) == gc2)
+ {
+ while (++i <= d)
+ if (tr (trans, tp[-i]) != tr (trans, sp[-i]))
+ break;
+ if (i > d)
+ {
+ for (i = d + skip + 1; i <= len; ++i)
+ if (tr (trans, tp[-i]) != tr (trans, sp[-i]))
+ break;
+ if (i > len)
+ {
+ *tpp = tp - len;
+ return true;
+ }
+ }
+ }
+
+ tp += d = kwset->shift[i - 2];
+ if (tp > ep)
+ break;
+ if (tr (trans, tp[-1]) != gc1)
+ {
+ if (d1)
+ tp += d1[U(tp[-1])];
+ break;
+ }
+ skip = i - 1;
+ }
+
+ *tpp = tp;
+ return false;
+}
+
+/* Return the address of the first byte in the buffer S (of size N)
+ that matches the terminal byte specified by KWSET, or null if there
+ is no match. KWSET->gc1 should be nonnegative. */
+static char const *
+memchr_kwset (char const *s, idx_t n, kwset_t kwset)
+{
+ char const *slim = s + n;
+ if (kwset->gc1help < 0)
+ {
+ for (; s < slim; s++)
+ if (kwset->next[U(*s)])
+ return s;
+ }
+ else
+ {
+ int small_heuristic = 2;
+ idx_t small_bytes = small_heuristic * sizeof (unsigned long int);
+ while (s < slim)
+ {
+ if (kwset->next[U(*s)])
+ return s;
+ s++;
+ if ((uintptr_t) s % small_bytes == 0)
+ return memchr2 (s, kwset->gc1, kwset->gc1help, slim - s);
+ }
+ }
+ return nullptr;
+}
+
+/* Fast Boyer-Moore search (inlinable version). */
+static inline ptrdiff_t _GL_ATTRIBUTE_PURE
+bmexec_trans (kwset_t kwset, char const *text, idx_t size)
+{
+ assume (0 <= size);
+ unsigned char const *d1;
+ char const *ep, *sp, *tp;
+ int d;
+ idx_t len = kwset->mind;
+ char const *trans = kwset->trans;
+
+ if (len == 0)
+ return 0;
+ if (len > size)
+ return -1;
+ if (len == 1)
+ {
+ tp = memchr_kwset (text, size, kwset);
+ return tp ? tp - text : -1;
+ }
+
+ d1 = kwset->delta;
+ sp = kwset->target + len;
+ tp = text + len;
+ char gc1 = kwset->gc1;
+ char gc2 = kwset->gc2;
+
+ /* Significance of 12: 1 (initial offset) + 10 (skip loop) + 1 (md2). */
+ idx_t len12;
+ if (!ckd_mul (&len12, len, 12) && len12 < size)
+ /* 11 is not a bug, the initial offset happens only once. */
+ for (ep = text + size - 11 * len; tp <= ep; )
+ {
+ char const *tp0 = tp;
+ d = d1[U(tp[-1])], tp += d;
+ d = d1[U(tp[-1])], tp += d;
+ if (d != 0)
+ {
+ d = d1[U(tp[-1])], tp += d;
+ d = d1[U(tp[-1])], tp += d;
+ d = d1[U(tp[-1])], tp += d;
+ if (d != 0)
+ {
+ d = d1[U(tp[-1])], tp += d;
+ d = d1[U(tp[-1])], tp += d;
+ d = d1[U(tp[-1])], tp += d;
+ if (d != 0)
+ {
+ d = d1[U(tp[-1])], tp += d;
+ d = d1[U(tp[-1])], tp += d;
+
+ /* As a heuristic, prefer memchr to seeking by
+ delta1 when the latter doesn't advance much. */
+ int advance_heuristic = 16 * sizeof (long);
+ if (advance_heuristic <= tp - tp0)
+ continue;
+ tp--;
+ tp = memchr_kwset (tp, text + size - tp, kwset);
+ if (! tp)
+ return -1;
+ tp++;
+ if (ep <= tp)
+ break;
+ }
+ }
+ }
+ if (bm_delta2_search (&tp, ep, sp, len, trans, gc1, gc2, d1, kwset))
+ return tp - text;
+ }
+
+ /* Now only a few characters are left to search. Carefully avoid
+ ever producing an out-of-bounds pointer. */
+ ep = text + size;
+ d = d1[U(tp[-1])];
+ while (d <= ep - tp)
+ {
+ d = d1[U((tp += d)[-1])];
+ if (d != 0)
+ continue;
+ if (bm_delta2_search (&tp, ep, sp, len, trans, gc1, gc2, nullptr, kwset))
+ return tp - text;
+ }
+
+ return -1;
+}
+
+/* Fast Boyer-Moore search. */
+static ptrdiff_t
+bmexec (kwset_t kwset, char const *text, idx_t size,
+ struct kwsmatch *kwsmatch, bool longest)
+{
+ /* Help the compiler inline in two ways, depending on whether
+ kwset->trans is null. */
+ ptrdiff_t ret = (IGNORE_DUPLICATE_BRANCH_WARNING
+ (kwset->trans
+ ? bmexec_trans (kwset, text, size)
+ : bmexec_trans (kwset, text, size)));
+ kwsmatch->index = 0;
+ kwsmatch->offset = ret;
+ kwsmatch->size = kwset->mind;
+ return ret;
+}
+
+/* Hairy multiple string search with the Aho-Corasick algorithm.
+ (inlinable version) */
+static inline ptrdiff_t
+acexec_trans (kwset_t kwset, char const *text, idx_t len,
+ struct kwsmatch *kwsmatch, bool longest)
+{
+ struct trie const *trie, *accept;
+ char const *tp, *left, *lim;
+ struct tree const *tree;
+ char const *trans;
+
+ /* Initialize register copies and look for easy ways out. */
+ if (len < kwset->mind)
+ return -1;
+ trans = kwset->trans;
+ trie = kwset->trie;
+ lim = text + len;
+ tp = text;
+
+ if (!trie->accepting)
+ {
+ unsigned char c;
+ int gc1 = kwset->gc1;
+
+ while (true)
+ {
+ if (gc1 < 0)
+ {
+ while (! (trie = kwset->next[c = tr (trans, *tp++)]))
+ if (tp >= lim)
+ return -1;
+ }
+ else
+ {
+ tp = memchr_kwset (tp, lim - tp, kwset);
+ if (!tp)
+ return -1;
+ c = tr (trans, *tp++);
+ trie = kwset->next[c];
+ }
+
+ while (true)
+ {
+ if (trie->accepting)
+ goto match;
+ if (tp >= lim)
+ return -1;
+ c = tr (trans, *tp++);
+
+ for (tree = trie->links; c != tree->label; )
+ {
+ tree = c < tree->label ? tree->llink : tree->rlink;
+ if (! tree)
+ {
+ trie = trie->fail;
+ if (!trie)
+ {
+ trie = kwset->next[c];
+ if (trie)
+ goto have_trie;
+ if (tp >= lim)
+ return -1;
+ goto next_c;
+ }
+ if (trie->accepting)
+ {
+ --tp;
+ goto match;
+ }
+ tree = trie->links;
+ }
+ }
+ trie = tree->trie;
+ have_trie:;
+ }
+ next_c:;
+ }
+ }
+
+ match:
+ accept = trie;
+ while (accept->accepting < 0)
+ accept = accept->fail;
+ left = tp - accept->depth;
+
+ /* Try left-most longest match. */
+ if (longest)
+ {
+ while (tp < lim)
+ {
+ struct trie const *accept1;
+ char const *left1;
+ unsigned char c = tr (trans, *tp++);
+
+ do
+ {
+ tree = trie->links;
+ while (tree && c != tree->label)
+ tree = c < tree->label ? tree->llink : tree->rlink;
+ }
+ while (!tree && (trie = trie->fail) && accept->depth <= trie->depth);
+
+ if (!tree)
+ break;
+ trie = tree->trie;
+ if (trie->accepting)
+ {
+ accept1 = trie;
+ while (accept1->accepting < 0)
+ accept1 = accept1->fail;
+ left1 = tp - accept1->depth;
+ if (left1 <= left)
+ {
+ left = left1;
+ accept = accept1;
+ }
+ }
+ }
+ }
+
+ kwsmatch->index = accept->accepting >> 1;
+ kwsmatch->offset = left - text;
+ kwsmatch->size = accept->depth;
+
+ return left - text;
+}
+
+/* Hairy multiple string search with Aho-Corasick algorithm. */
+static ptrdiff_t
+acexec (kwset_t kwset, char const *text, idx_t size,
+ struct kwsmatch *kwsmatch, bool longest)
+{
+ assume (0 <= size);
+ /* Help the compiler inline in two ways, depending on whether
+ kwset->trans is null. */
+ return (IGNORE_DUPLICATE_BRANCH_WARNING
+ (kwset->trans
+ ? acexec_trans (kwset, text, size, kwsmatch, longest)
+ : acexec_trans (kwset, text, size, kwsmatch, longest)));
+}
+
+/* Find the first instance of a KWSET member in TEXT, which has SIZE bytes.
+ Return the offset (into TEXT) of the first byte of the matching substring,
+ or -1 if no match is found. Upon a match, store details in
+ *KWSMATCH: index of matched keyword, start offset (same as the return
+ value), and length. If LONGEST, find the longest match; otherwise
+ any match will do. */
+ptrdiff_t
+kwsexec (kwset_t kwset, char const *text, idx_t size,
+ struct kwsmatch *kwsmatch, bool longest)
+{
+ return kwset->kwsexec (kwset, text, size, kwsmatch, longest);
+}
+
+/* Free the components of the given keyword set. */
+void
+kwsfree (kwset_t kwset)
+{
+ obstack_free (&kwset->obstack, nullptr);
+ free (kwset);
+}
diff --git a/lib/kwset.h b/lib/kwset.h
new file mode 100644
index 0000000000..df9ce087f6
--- /dev/null
+++ b/lib/kwset.h
@@ -0,0 +1,44 @@
+/* kwset.h - header declaring the keyword set library.
+ Copyright (C) 1989, 1998, 2005, 2007, 2009-2025 Free Software Foundation,
+ Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written August 1989 by Mike Haertel. */
+
+#include <stddef.h>
+
+#include <idx.h>
+
+struct kwsmatch
+{
+ idx_t index; /* Index number of matching keyword. */
+ idx_t offset; /* Offset of match. */
+ idx_t size; /* Length of match. */
+};
+
+#include <arg-nonnull.h>
+#include <idx.h>
+
+struct kwset;
+typedef struct kwset *kwset_t;
+
+extern kwset_t kwsalloc (char const *);
+extern void kwsincr (kwset_t, char const *, idx_t);
+extern idx_t kwswords (kwset_t) _GL_ATTRIBUTE_PURE;
+extern void kwsprep (kwset_t);
+extern ptrdiff_t kwsexec (kwset_t, char const *, idx_t,
+ struct kwsmatch *, bool)
+ _GL_ARG_NONNULL ((4));
+extern void kwsfree (kwset_t);
diff --git a/modules/kwset b/modules/kwset
new file mode 100644
index 0000000000..9fb64402fd
--- /dev/null
+++ b/modules/kwset
@@ -0,0 +1,33 @@
+Description:
+Searching for any of a given set of fixed strings in text.
+
+Files:
+lib/kwset.h
+lib/kwset.c
+
+Depends-on:
+idx
+memchr2
+minmax
+nullptr
+obstack
+snippet/arg-nonnull
+stdckdint-h
+stdint-h
+verify
+xalloc
+
+configure.ac:
+AC_REQUIRE([AC_C_INLINE])
+
+Makefile.am:
+lib_SOURCES += kwset.c
+
+Include:
+"kwset.h"
+
+License:
+GPL
+
+Maintainer:
+all
--
2.43.0
>From e332950f1edd1d2d3e02662a6da8c1f0b26c999b Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Wed, 25 Jun 2025 14:28:25 +0200
Subject: [PATCH 2/3] kwset: Usability tweaks.
* lib/kwset.h: Make header idempotent and C++ safe. Check that config.h
was already included.
---
ChangeLog | 4 ++++
lib/kwset.h | 24 ++++++++++++++++++++----
2 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index c9c4485672..b742e91601 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
2025-06-25 Bruno Haible <br...@clisp.org>
+ kwset: Usability tweaks.
+ * lib/kwset.h: Make header idempotent and C++ safe. Check that config.h
+ was already included.
+
kwset: New module.
* lib/kwset.h: New file, from GNU grep.
* lib/kwset.c: New file, from GNU grep.
diff --git a/lib/kwset.h b/lib/kwset.h
index df9ce087f6..204f409808 100644
--- a/lib/kwset.h
+++ b/lib/kwset.h
@@ -17,9 +17,22 @@
/* Written August 1989 by Mike Haertel. */
+#ifndef _KWSET_H
+#define _KWSET_H
+
+/* This file uses _GL_ATTRIBUTE_PURE. */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
#include <stddef.h>
-#include <idx.h>
+#include "arg-nonnull.h"
+#include "idx.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
struct kwsmatch
{
@@ -28,9 +41,6 @@ struct kwsmatch
idx_t size; /* Length of match. */
};
-#include <arg-nonnull.h>
-#include <idx.h>
-
struct kwset;
typedef struct kwset *kwset_t;
@@ -42,3 +52,9 @@ extern ptrdiff_t kwsexec (kwset_t, char const *, idx_t,
struct kwsmatch *, bool)
_GL_ARG_NONNULL ((4));
extern void kwsfree (kwset_t);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _KWSET_H */
--
2.43.0
>From 84f19f053c483ae5268c580c9629abc2d08d41f5 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Wed, 25 Jun 2025 15:52:40 +0200
Subject: [PATCH 3/3] kwset: Add tests.
* lib/kwset.c (kwsexec): Correct documentation.
* tests/test-kwset.c: New file.
* modules/kwset-tests: New file.
---
ChangeLog | 5 ++
lib/kwset.c | 12 ++--
modules/kwset-tests | 11 ++++
tests/test-kwset.c | 148 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 172 insertions(+), 4 deletions(-)
create mode 100644 modules/kwset-tests
create mode 100644 tests/test-kwset.c
diff --git a/ChangeLog b/ChangeLog
index b742e91601..1a9a4a9ada 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
2025-06-25 Bruno Haible <br...@clisp.org>
+ kwset: Add tests.
+ * lib/kwset.c (kwsexec): Correct documentation.
+ * tests/test-kwset.c: New file.
+ * modules/kwset-tests: New file.
+
kwset: Usability tweaks.
* lib/kwset.h: Make header idempotent and C++ safe. Check that config.h
was already included.
diff --git a/lib/kwset.c b/lib/kwset.c
index 5a3b9c9919..2784ba5371 100644
--- a/lib/kwset.c
+++ b/lib/kwset.c
@@ -916,10 +916,14 @@ acexec (kwset_t kwset, char const *text, idx_t size,
/* Find the first instance of a KWSET member in TEXT, which has SIZE bytes.
Return the offset (into TEXT) of the first byte of the matching substring,
- or -1 if no match is found. Upon a match, store details in
- *KWSMATCH: index of matched keyword, start offset (same as the return
- value), and length. If LONGEST, find the longest match; otherwise
- any match will do. */
+ or -1 if no match is found.
+ Upon a match:
+ - Store details in *KWSMATCH: index of matched keyword, start offset
+ (same as the return value), and length.
+ - If LONGEST, find the longest match that starts at this offset;
+ otherwise any match that starts at this offset will do.
+ NOTE! LONGEST does *not* mean to search for the longest KWSET member
+ across the entire string. */
ptrdiff_t
kwsexec (kwset_t kwset, char const *text, idx_t size,
struct kwsmatch *kwsmatch, bool longest)
diff --git a/modules/kwset-tests b/modules/kwset-tests
new file mode 100644
index 0000000000..25e46338d0
--- /dev/null
+++ b/modules/kwset-tests
@@ -0,0 +1,11 @@
+Files:
+tests/test-kwset.c
+tests/macros.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-kwset
+check_PROGRAMS += test-kwset
diff --git a/tests/test-kwset.c b/tests/test-kwset.c
new file mode 100644
index 0000000000..e25d7a23b2
--- /dev/null
+++ b/tests/test-kwset.c
@@ -0,0 +1,148 @@
+/* Test of searching for any of a given set of fixed strings in text.
+ Copyright (C) 2025 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <br...@clisp.org>, 2025. */
+
+#include <config.h>
+
+/* Specification. */
+#include "kwset.h"
+
+#include "macros.h"
+
+int
+main ()
+{
+ /* Trivial case. */
+ {
+ kwset_t set = kwsalloc (NULL);
+ kwsprep (set);
+
+ ASSERT (kwswords (set) == 0);
+
+ static const char input[] = "foo";
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, input, 3, &match, false);
+ ASSERT (ret == -1);
+
+ kwsfree (set);
+ }
+
+ /* Simple case: one fixed string. */
+ {
+ kwset_t set = kwsalloc (NULL);
+ kwsincr (set, "acab", 4);
+ kwsprep (set);
+
+ ASSERT (kwswords (set) == 1);
+
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabracab", 14, &match, false);
+ ASSERT (ret == 10);
+ ASSERT (match.offset == ret);
+ ASSERT (match.index == 0);
+ ASSERT (match.size == 4);
+ }
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabra", 11, &match, false);
+ ASSERT (ret == -1);
+ }
+
+ kwsfree (set);
+ }
+
+ /* Any match vs. longest left-most match. */
+ {
+ kwset_t set = kwsalloc (NULL);
+ kwsincr (set, "acab", 4);
+ kwsincr (set, "acacia", 6);
+ kwsprep (set);
+
+ ASSERT (kwswords (set) == 2);
+
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabracabatacaciaeinacabemia", 33, &match, false);
+ ASSERT (ret == 10);
+ ASSERT (match.offset == ret);
+ ASSERT (match.index == 0);
+ ASSERT (match.size == 4);
+ }
+ /* longest = true makes no difference, because it's only about the left-most match. */
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabracabatacaciaeinacabemia", 33, &match, true);
+ ASSERT (ret == 10);
+ ASSERT (match.offset == ret);
+ ASSERT (match.index == 0);
+ ASSERT (match.size == 4);
+ }
+
+ kwsfree (set);
+ }
+
+ /* Any match vs. longest left-most match. */
+ {
+ kwset_t set = kwsalloc (NULL);
+ kwsincr (set, "acab", 4);
+ kwsincr (set, "acabe", 5);
+ kwsprep (set);
+
+ ASSERT (kwswords (set) == 2);
+
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabracabatacaciaeinacabemia", 33, &match, false);
+ ASSERT (ret == 10);
+ ASSERT (match.offset == ret);
+ ASSERT (match.index == 0);
+ ASSERT (match.size == 4);
+ }
+ /* longest = true makes no difference, because it's only about the left-most match. */
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabracabatacaciaeinacabemia", 33, &match, true);
+ ASSERT (ret == 10);
+ ASSERT (match.offset == ret);
+ ASSERT (match.index == 0);
+ ASSERT (match.size == 4);
+ }
+
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabracabematacaciaeinacabia", 33, &match, false);
+ ASSERT (ret == 10);
+ ASSERT (match.offset == ret);
+ ASSERT (match.index == 0);
+ ASSERT (match.size == 4);
+ }
+ /* Here, longest = true makes a difference. */
+ {
+ struct kwsmatch match;
+ ptrdiff_t ret = kwsexec (set, "abracadabracabematacaciaeinacabia", 33, &match, true);
+ ASSERT (ret == 10);
+ ASSERT (match.offset == ret);
+ ASSERT (match.index == 1);
+ ASSERT (match.size == 5);
+ }
+
+ kwsfree (set);
+ }
+
+ return test_exit_status;
+}
--
2.43.0
