merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/ewah/bitmap.c

@@ -0,0 +1,180 @@
+/**
+ * Copyright 2013, GitHub, Inc
+ * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
+ *	David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
+ *
+ * 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 2
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+#include "cache.h"
+#include "ewok.h"
+
+#define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
+#define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
+
+struct bitmap *bitmap_new(void)
+{
+	struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
+	bitmap->words = xcalloc(32, sizeof(eword_t));
+	bitmap->word_alloc = 32;
+	return bitmap;
+}
+
+void bitmap_set(struct bitmap *self, size_t pos)
+{
+	size_t block = EWAH_BLOCK(pos);
+
+	if (block >= self->word_alloc) {
+		size_t old_size = self->word_alloc;
+		self->word_alloc = block * 2;
+		REALLOC_ARRAY(self->words, self->word_alloc);
+		memset(self->words + old_size, 0x0,
+			(self->word_alloc - old_size) * sizeof(eword_t));
+	}
+
+	self->words[block] |= EWAH_MASK(pos);
+}
+
+int bitmap_get(struct bitmap *self, size_t pos)
+{
+	size_t block = EWAH_BLOCK(pos);
+	return block < self->word_alloc &&
+		(self->words[block] & EWAH_MASK(pos)) != 0;
+}
+
+struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
+{
+	struct ewah_bitmap *ewah = ewah_new();
+	size_t i, running_empty_words = 0;
+	eword_t last_word = 0;
+
+	for (i = 0; i < bitmap->word_alloc; ++i) {
+		if (bitmap->words[i] == 0) {
+			running_empty_words++;
+			continue;
+		}
+
+		if (last_word != 0)
+			ewah_add(ewah, last_word);
+
+		if (running_empty_words > 0) {
+			ewah_add_empty_words(ewah, 0, running_empty_words);
+			running_empty_words = 0;
+		}
+
+		last_word = bitmap->words[i];
+	}
+
+	ewah_add(ewah, last_word);
+	return ewah;
+}
+
+struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
+{
+	struct bitmap *bitmap = bitmap_new();
+	struct ewah_iterator it;
+	eword_t blowup;
+	size_t i = 0;
+
+	ewah_iterator_init(&it, ewah);
+
+	while (ewah_iterator_next(&blowup, &it)) {
+		ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
+		bitmap->words[i++] = blowup;
+	}
+
+	bitmap->word_alloc = i;
+	return bitmap;
+}
+
+void bitmap_and_not(struct bitmap *self, struct bitmap *other)
+{
+	const size_t count = (self->word_alloc < other->word_alloc) ?
+		self->word_alloc : other->word_alloc;
+
+	size_t i;
+
+	for (i = 0; i < count; ++i)
+		self->words[i] &= ~other->words[i];
+}
+
+void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
+{
+	size_t original_size = self->word_alloc;
+	size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
+	size_t i = 0;
+	struct ewah_iterator it;
+	eword_t word;
+
+	if (self->word_alloc < other_final) {
+		self->word_alloc = other_final;
+		REALLOC_ARRAY(self->words, self->word_alloc);
+		memset(self->words + original_size, 0x0,
+			(self->word_alloc - original_size) * sizeof(eword_t));
+	}
+
+	ewah_iterator_init(&it, other);
+
+	while (ewah_iterator_next(&word, &it))
+		self->words[i++] |= word;
+}
+
+size_t bitmap_popcount(struct bitmap *self)
+{
+	size_t i, count = 0;
+
+	for (i = 0; i < self->word_alloc; ++i)
+		count += ewah_bit_popcount64(self->words[i]);
+
+	return count;
+}
+
+int bitmap_equals(struct bitmap *self, struct bitmap *other)
+{
+	struct bitmap *big, *small;
+	size_t i;
+
+	if (self->word_alloc < other->word_alloc) {
+		small = self;
+		big = other;
+	} else {
+		small = other;
+		big = self;
+	}
+
+	for (i = 0; i < small->word_alloc; ++i) {
+		if (small->words[i] != big->words[i])
+			return 0;
+	}
+
+	for (; i < big->word_alloc; ++i) {
+		if (big->words[i] != 0)
+			return 0;
+	}
+
+	return 1;
+}
+
+void bitmap_reset(struct bitmap *bitmap)
+{
+	memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
+}
+
+void bitmap_free(struct bitmap *bitmap)
+{
+	if (bitmap == NULL)
+		return;
+
+	free(bitmap->words);
+	free(bitmap);
+}