view mercurial/thirdparty/xdiff/xutils.c @ 42172:71d8b4d91616 stable

setup: properly package distutils in py2exe virtualenv builds

Our in-repo py2exe packaging code uses virtualenvs for managing
dependencies. An advantage of this is that packaging is more
deterministic and reproducible. Without virtualenvs, we need to
install packages in the system Python install. Packages installed
by other consumers of the system Python could leak into the Mercurial
package.

A regression from this change was that py2exe packages contained
the virtualenv's hacked distutils modules instead of the original
distutils modules. (virtualenv installs a hacked distutils module
because distutils uses relative path lookups that fail when running
from a virtualenv.)

This commit introduces a workaround so py2exe packaging uses the
original distutils modules when running from a virtualenv.

With this change, `import distutils` no longer fails from py2exe
builds produced from a virtualenv. This fixes the regression.
Furthermore, we now include all distutils modules. Before, py2exe's
module finding would only find modules there were explicitly
referenced in code. So, we now package a complete copy of distutils
instead of a partial one. This is even better than before.

# no-check-commit foo_bar function name

/*
 *  LibXDiff by Davide Libenzi ( File Differential Library )
 *  Copyright (C) 2003	Davide Libenzi
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, see
 *  <http://www.gnu.org/licenses/>.
 *
 *  Davide Libenzi <[e-mail]>
 *
 */

#include <limits.h>
#include <assert.h>
#include "xinclude.h"




int64_t xdl_bogosqrt(int64_t n) {
	int64_t i;

	/*
	 * Classical integer square root approximation using shifts.
	 */
	for (i = 1; n > 0; n >>= 2)
		i <<= 1;

	return i;
}


void *xdl_mmfile_first(mmfile_t *mmf, int64_t *size)
{
	*size = mmf->size;
	return mmf->ptr;
}


int64_t xdl_mmfile_size(mmfile_t *mmf)
{
	return mmf->size;
}


int xdl_cha_init(chastore_t *cha, int64_t isize, int64_t icount) {

	cha->head = cha->tail = NULL;
	cha->isize = isize;
	cha->nsize = icount * isize;
	cha->ancur = cha->sncur = NULL;
	cha->scurr = 0;

	return 0;
}


void xdl_cha_free(chastore_t *cha) {
	chanode_t *cur, *tmp;

	for (cur = cha->head; (tmp = cur) != NULL;) {
		cur = cur->next;
		xdl_free(tmp);
	}
}


void *xdl_cha_alloc(chastore_t *cha) {
	chanode_t *ancur;
	void *data;

	if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
		if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {

			return NULL;
		}
		ancur->icurr = 0;
		ancur->next = NULL;
		if (cha->tail)
			cha->tail->next = ancur;
		if (!cha->head)
			cha->head = ancur;
		cha->tail = ancur;
		cha->ancur = ancur;
	}

	data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
	ancur->icurr += cha->isize;

	return data;
}

int64_t xdl_guess_lines(mmfile_t *mf, int64_t sample) {
	int64_t nl = 0, size, tsize = 0;
	char const *data, *cur, *top;

	if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
		for (top = data + size; nl < sample && cur < top; ) {
			nl++;
			if (!(cur = memchr(cur, '\n', top - cur)))
				cur = top;
			else
				cur++;
		}
		tsize += (long) (cur - data);
	}

	if (nl && tsize)
		nl = xdl_mmfile_size(mf) / (tsize / nl);

	return nl + 1;
}

int xdl_recmatch(const char *l1, int64_t s1, const char *l2, int64_t s2)
{
	if (s1 == s2 && !memcmp(l1, l2, s1))
		return 1;
	return 0;
}

uint64_t xdl_hash_record(char const **data, char const *top) {
	uint64_t ha = 5381;
	char const *ptr = *data;

	for (; ptr < top && *ptr != '\n'; ptr++) {
		ha += (ha << 5);
		ha ^= (unsigned long) *ptr;
	}
	*data = ptr < top ? ptr + 1: ptr;

	return ha;
}

unsigned int xdl_hashbits(int64_t size) {
	int64_t val = 1;
	unsigned int bits = 0;

	for (; val < size && bits < (int64_t) CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
	return bits ? bits: 1;
}