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authorPaul Eggert <eggert@cs.ucla.edu>2016-12-30 02:33:10 (GMT)
committerPaul Eggert <eggert@cs.ucla.edu>2016-12-30 02:33:50 (GMT)
commite86def3d68d09aaf8f527e910178d778073dc837 (patch)
tree0533fd1e8f1aeb0e358c0310e189c6f9509bb5ba
parentbb3d1acbea88ced0cf4a93baa4ee8f2862f9e1ac (diff)
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grep: int cleanup in kwset.c
This should affect only theoretical bugs with very large inputs. On my platform, this patch shrinks the grep text by 136 bytes. * src/kwset.c: Include intprops.h, for INT_MULTIPLY_WRAPV. (struct trie, struct kwset, kwsalloc, kwsincr, treedelta, kwsprep) (bm_delta2_search, bmexec_trans, cwexec): Prefer ptrdiff_t to int when counts can exceed INT_MAX in large inputs, at least in theory. (hasevery): Use bool for booleans. (bmexec_trans): Avoid undefined behavior on integer overflow.
-rw-r--r--src/kwset.c45
1 files changed, 23 insertions, 22 deletions
diff --git a/src/kwset.c b/src/kwset.c
index 506c6cd..2e59be0 100644
--- a/src/kwset.c
+++ b/src/kwset.c
@@ -38,6 +38,7 @@
#include <stdint.h>
#include <sys/types.h>
#include "system.h"
+#include "intprops.h"
#include "memchr2.h"
#include "obstack.h"
#include "xalloc.h"
@@ -69,9 +70,9 @@ struct trie
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. */
- int depth; /* Depth of this node from the root. */
- int shift; /* Shift function for search failures. */
- int maxshift; /* Max shift of self and descendants. */
+ ptrdiff_t depth; /* Depth of this node from the root. */
+ ptrdiff_t shift; /* Shift function for search failures. */
+ ptrdiff_t maxshift; /* Max shift of self and descendants. */
};
/* Structure returned opaquely to the caller, containing everything. */
@@ -80,12 +81,12 @@ struct kwset
struct obstack obstack; /* Obstack for node allocation. */
ptrdiff_t words; /* Number of words in the trie. */
struct trie *trie; /* The trie itself. */
- int mind; /* Minimum depth of an accepting node. */
- int maxd; /* Maximum depth of any node. */
+ ptrdiff_t mind; /* Minimum depth of an accepting node. */
+ ptrdiff_t maxd; /* Maximum depth of any 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. */
- int *shift; /* Used in Boyer-Moore search for one string. */
+ ptrdiff_t *shift; /* Used in Boyer-Moore search for one string. */
char const *trans; /* Character translation table. */
/* If there's only one string, this is the string's last byte,
@@ -142,7 +143,7 @@ kwsalloc (char const *trans, bool reverse)
kwset->trie->fail = NULL;
kwset->trie->depth = 0;
kwset->trie->shift = 0;
- kwset->mind = INT_MAX;
+ kwset->mind = PTRDIFF_MAX;
kwset->maxd = -1;
kwset->target = NULL;
kwset->trans = trans;
@@ -181,7 +182,7 @@ kwsincr (kwset_t kwset, char const *text, size_t len)
enum { L, R } dirs[DEPTH_SIZE];
links[0] = (struct tree *) &trie->links;
dirs[0] = L;
- int depth = 1;
+ ptrdiff_t depth = 1;
while (cur && label != cur->label)
{
@@ -355,9 +356,7 @@ treefails (struct tree const *tree, struct trie const *fail,
/* 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,
- unsigned int depth,
- unsigned char delta[])
+treedelta (struct tree const *tree, ptrdiff_t depth, unsigned char delta[])
{
if (!tree)
return;
@@ -368,15 +367,15 @@ treedelta (struct tree const *tree,
}
/* Return true if A has every label in B. */
-static int _GL_ATTRIBUTE_PURE
+static bool _GL_ATTRIBUTE_PURE
hasevery (struct tree const *a, struct tree const *b)
{
if (!b)
- return 1;
+ return true;
if (!hasevery(a, b->llink))
- return 0;
+ return false;
if (!hasevery(a, b->rlink))
- return 0;
+ return false;
while (a && b->label != a->label)
if (b->label < a->label)
a = a->llink;
@@ -403,7 +402,7 @@ void
kwsprep (kwset_t kwset)
{
char const *trans = kwset->trans;
- int i;
+ ptrdiff_t i;
unsigned char deltabuf[NCHAR];
unsigned char *delta = trans ? deltabuf : kwset->delta;
struct trie *curr, *last;
@@ -565,16 +564,17 @@ kwsprep (kwset_t kwset)
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, int len,
+bm_delta2_search (char const **tpp, char const *ep, char const *sp,
+ ptrdiff_t len,
char const *trans, char gc1, char gc2,
unsigned char const *d1, kwset_t kwset)
{
char const *tp = *tpp;
- int d = len, skip = 0;
+ ptrdiff_t d = len, skip = 0;
while (true)
{
- int i = 2;
+ ptrdiff_t i = 2;
if (tr (trans, tp[-2]) == gc2)
{
while (++i <= d)
@@ -663,7 +663,7 @@ bmexec_trans (kwset_t kwset, char const *text, size_t size)
unsigned char const *d1;
char const *ep, *sp, *tp;
int d;
- int len = kwset->mind;
+ ptrdiff_t len = kwset->mind;
char const *trans = kwset->trans;
if (len == 0)
@@ -683,7 +683,8 @@ bmexec_trans (kwset_t kwset, char const *text, size_t size)
char gc2 = kwset->gc2;
/* Significance of 12: 1 (initial offset) + 10 (skip loop) + 1 (md2). */
- if (size > 12 * len)
+ ptrdiff_t len12;
+ if (!INT_MULTIPLY_WRAPV (len, 12, &len12) && len12 < size)
/* 11 is not a bug, the initial offset happens only once. */
for (ep = text + size - 11 * len; tp <= ep; )
{
@@ -772,7 +773,7 @@ cwexec (kwset_t kwset, char const *text, size_t len,
char const *beg, *lim, *mch, *lmch;
unsigned char c;
unsigned char const *delta;
- int d;
+ ptrdiff_t d;
char const *end, *qlim;
struct tree const *tree;
char const *trans;