Merge branch 'pw/xdiff-alloc'

Add a level of redirection to array allocation API in xdiff part,
to make it easier to share with the libgit2 project.

* pw/xdiff-alloc:
  xdiff: introduce XDL_ALLOC_GROW()
  xdiff: introduce XDL_CALLOC_ARRAY()
  xdiff: introduce xdl_calloc
  xdiff: introduce XDL_ALLOC_ARRAY()

Author: gitster

xdiff/xdiff.h

@@ -120,6 +120,7 @@ typedef struct s_bdiffparam {
 
 
 #define xdl_malloc(x) xmalloc(x)
+#define xdl_calloc(n, sz) xcalloc(n, sz)
 #define xdl_free(ptr) free(ptr)
 #define xdl_realloc(ptr,x) xrealloc(ptr,x)
 

xdiff/xdiffi.c

@@ -337,7 +337,7 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	 * One is to store the forward path and one to store the backward path.
 	 */
 	ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
-	if (!(kvd = (long *) xdl_malloc((2 * ndiags + 2) * sizeof(long)))) {
+	if (!XDL_ALLOC_ARRAY(kvd, 2 * ndiags + 2)) {
 
 		xdl_free_env(xe);
 		return -1;

xdiff/xhistogram.c

@@ -251,7 +251,7 @@ static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
 		    int line1, int count1, int line2, int count2)
 {
 	int b_ptr;
-	int sz, ret = -1;
+	int ret = -1;
 	struct histindex index;
 
 	memset(&index, 0, sizeof(index));
@@ -265,23 +265,16 @@ static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
 	index.rcha.head = NULL;
 
 	index.table_bits = xdl_hashbits(count1);
-	sz = index.records_size = 1 << index.table_bits;
-	sz *= sizeof(struct record *);
-	if (!(index.records = (struct record **) xdl_malloc(sz)))
+	index.records_size = 1 << index.table_bits;
+	if (!XDL_CALLOC_ARRAY(index.records, index.records_size))
 		goto cleanup;
-	memset(index.records, 0, sz);
 
-	sz = index.line_map_size = count1;
-	sz *= sizeof(struct record *);
-	if (!(index.line_map = (struct record **) xdl_malloc(sz)))
+	index.line_map_size = count1;
+	if (!XDL_CALLOC_ARRAY(index.line_map, index.line_map_size))
 		goto cleanup;
-	memset(index.line_map, 0, sz);
 
-	sz = index.line_map_size;
-	sz *= sizeof(unsigned int);
-	if (!(index.next_ptrs = (unsigned int *) xdl_malloc(sz)))
+	if (!XDL_CALLOC_ARRAY(index.next_ptrs, index.line_map_size))
 		goto cleanup;
-	memset(index.next_ptrs, 0, sz);
 
 	/* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */
 	if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0)

xdiff/xmacros.h

@@ -49,5 +49,23 @@ do { \
 		((unsigned long) __p[2]) << 16 | ((unsigned long) __p[3]) << 24; \
 } while (0)
 
+/* Allocate an array of nr elements, returns NULL on failure */
+#define XDL_ALLOC_ARRAY(p, nr)				\
+	((p) = SIZE_MAX / sizeof(*(p)) >= (size_t)(nr)	\
+		? xdl_malloc((nr) * sizeof(*(p)))	\
+		: NULL)
+
+/* Allocate an array of nr zeroed out elements, returns NULL on failure */
+#define XDL_CALLOC_ARRAY(p, nr)	((p) = xdl_calloc(nr, sizeof(*(p))))
+
+/*
+ * Ensure array p can accommodate at least nr elements, growing the
+ * array and updating alloc (which is the number of allocated
+ * elements) as necessary. Frees p and returns -1 on failure, returns
+ * 0 on success
+ */
+#define XDL_ALLOC_GROW(p, nr, alloc)	\
+	(-!((nr) <= (alloc) ||		\
+	    ((p) = xdl_alloc_grow_helper((p), (nr), &(alloc), sizeof(*(p))))))
 
 #endif /* #if !defined(XMACROS_H) */

xdiff/xpatience.c

@@ -151,11 +151,8 @@ static int fill_hashmap(mmfile_t *file1, mmfile_t *file2,
 
 	/* We know exactly how large we want the hash map */
 	result->alloc = count1 * 2;
-	result->entries = (struct entry *)
-		xdl_malloc(result->alloc * sizeof(struct entry));
-	if (!result->entries)
+	if (!XDL_CALLOC_ARRAY(result->entries, result->alloc))
 		return -1;
-	memset(result->entries, 0, result->alloc * sizeof(struct entry));
 
 	/* First, fill with entries from the first file */
 	while (count1--)
@@ -200,7 +197,7 @@ static int binary_search(struct entry **sequence, int longest,
  */
 static int find_longest_common_sequence(struct hashmap *map, struct entry **res)
 {
-	struct entry **sequence = xdl_malloc(map->nr * sizeof(struct entry *));
+	struct entry **sequence;
 	int longest = 0, i;
 	struct entry *entry;
 
@@ -211,7 +208,7 @@ static int find_longest_common_sequence(struct hashmap *map, struct entry **res)
 	 */
 	int anchor_i = -1;
 
-	if (!sequence)
+	if (!XDL_ALLOC_ARRAY(sequence, map->nr))
 		return -1;
 
 	for (entry = map->first; entry; entry = entry->next) {

xdiff/xprepare.c

@@ -78,15 +78,14 @@ static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) {
 
 		return -1;
 	}
-	if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) {
+	if (!XDL_CALLOC_ARRAY(cf->rchash, cf->hsize)) {
 
 		xdl_cha_free(&cf->ncha);
 		return -1;
 	}
-	memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *));
 
 	cf->alloc = size;
-	if (!(cf->rcrecs = (xdlclass_t **) xdl_malloc(cf->alloc * sizeof(xdlclass_t *)))) {
+	if (!XDL_ALLOC_ARRAY(cf->rcrecs, cf->alloc)) {
 
 		xdl_free(cf->rchash);
 		xdl_cha_free(&cf->ncha);
@@ -112,7 +111,6 @@ static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t
 	long hi;
 	char const *line;
 	xdlclass_t *rcrec;
-	xdlclass_t **rcrecs;
 
 	line = rec->ptr;
 	hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
@@ -128,14 +126,8 @@ static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t
 			return -1;
 		}
 		rcrec->idx = cf->count++;
-		if (cf->count > cf->alloc) {
-			cf->alloc *= 2;
-			if (!(rcrecs = (xdlclass_t **) xdl_realloc(cf->rcrecs, cf->alloc * sizeof(xdlclass_t *)))) {
-
+		if (XDL_ALLOC_GROW(cf->rcrecs, cf->count, cf->alloc))
 				return -1;
-			}
-			cf->rcrecs = rcrecs;
-		}
 		cf->rcrecs[rcrec->idx] = rcrec;
 		rcrec->line = line;
 		rcrec->size = rec->size;
@@ -164,7 +156,7 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
 	unsigned long hav;
 	char const *blk, *cur, *top, *prev;
 	xrecord_t *crec;
-	xrecord_t **recs, **rrecs;
+	xrecord_t **recs;
 	xrecord_t **rhash;
 	unsigned long *ha;
 	char *rchg;
@@ -178,26 +170,21 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
 
 	if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0)
 		goto abort;
-	if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *))))
+	if (!XDL_ALLOC_ARRAY(recs, narec))
 		goto abort;
 
 	hbits = xdl_hashbits((unsigned int) narec);
 	hsize = 1 << hbits;
-	if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *))))
+	if (!XDL_CALLOC_ARRAY(rhash, hsize))
 		goto abort;
-	memset(rhash, 0, hsize * sizeof(xrecord_t *));
 
 	nrec = 0;
 	if ((cur = blk = xdl_mmfile_first(mf, &bsize))) {
 		for (top = blk + bsize; cur < top; ) {
 			prev = cur;
 			hav = xdl_hash_record(&cur, top, xpp->flags);
-			if (nrec >= narec) {
-				narec *= 2;
-				if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *))))
-					goto abort;
-				recs = rrecs;
-			}
+			if (XDL_ALLOC_GROW(recs, nrec + 1, narec))
+				goto abort;
 			if (!(crec = xdl_cha_alloc(&xdf->rcha)))
 				goto abort;
 			crec->ptr = prev;
@@ -209,15 +196,14 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
 		}
 	}
 
-	if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char))))
+	if (!XDL_CALLOC_ARRAY(rchg, nrec + 2))
 		goto abort;
-	memset(rchg, 0, (nrec + 2) * sizeof(char));
 
 	if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) &&
 	    (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)) {
-		if (!(rindex = xdl_malloc((nrec + 1) * sizeof(*rindex))))
+		if (!XDL_ALLOC_ARRAY(rindex, nrec + 1))
 			goto abort;
-		if (!(ha = xdl_malloc((nrec + 1) * sizeof(*ha))))
+		if (!XDL_ALLOC_ARRAY(ha, nrec + 1))
 			goto abort;
 	}
 
@@ -383,11 +369,8 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
 	xdlclass_t *rcrec;
 	char *dis, *dis1, *dis2;
 
-	if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) {
-
+	if (!XDL_CALLOC_ARRAY(dis, xdf1->nrec + xdf2->nrec + 2))
 		return -1;
-	}
-	memset(dis, 0, xdf1->nrec + xdf2->nrec + 2);
 	dis1 = dis;
 	dis2 = dis1 + xdf1->nrec + 1;
 

xdiff/xutils.c

@@ -432,3 +432,20 @@ int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
 
 	return 0;
 }
+
+void* xdl_alloc_grow_helper(void *p, long nr, long *alloc, size_t size)
+{
+	void *tmp = NULL;
+	size_t n = ((LONG_MAX - 16) / 2 >= *alloc) ? 2 * *alloc + 16 : LONG_MAX;
+	if (nr > n)
+		n = nr;
+	if (SIZE_MAX / size >= n)
+		tmp = xdl_realloc(p, n * size);
+	if (tmp) {
+		*alloc = n;
+	} else {
+		xdl_free(p);
+		*alloc = 0;
+	}
+	return tmp;
+}

xdiff/xutils.h

@@ -42,6 +42,7 @@ int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
 		       int line1, int count1, int line2, int count2);
 
-
+/* Do not call this function, use XDL_ALLOC_GROW instead */
+void* xdl_alloc_grow_helper(void* p, long nr, long* alloc, size_t size);
 
 #endif /* #if !defined(XUTILS_H) */