plugins/hg4idea/testData/bin/mercurial/mpatch.c - platform/tools/idea - Git at Google

 /*
  mpatch.c - efficient binary patching for Mercurial

  This implements a patch algorithm that's O(m + nlog n) where m is the
  size of the output and n is the number of patches.

  Given a list of binary patches, it unpacks each into a hunk list,
  then combines the hunk lists with a treewise recursion to form a
  single hunk list. This hunk list is then applied to the original
  text.

  The text (or binary) fragments are copied directly from their source
  Python objects into a preallocated output string to avoid the
  allocation of intermediate Python objects. Working memory is about 2x
  the total number of hunks.

  Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>

  This software may be used and distributed according to the terms
  of the GNU General Public License, incorporated herein by reference.
 */

 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
 #include <stdlib.h>
 #include <string.h>

 #include "util.h"

 static char mpatch_doc[] = "Efficient binary patching.";
 static PyObject *mpatch_Error;

 struct frag {
 	int start, end, len;
 	const char *data;
 };

 struct flist {
 	struct frag *base, *head, *tail;
 };

 static struct flist *lalloc(Py_ssize_t size)
 {
 	struct flist *a = NULL;

 	if (size < 1)
 		size = 1;

 	a = (struct flist *)malloc(sizeof(struct flist));
 	if (a) {
 		a->base = (struct frag *)malloc(sizeof(struct frag) * size);
 		if (a->base) {
 			a->head = a->tail = a->base;
 			return a;
 		}
 		free(a);
 		a = NULL;
 	}
 	if (!PyErr_Occurred())
 		PyErr_NoMemory();
 	return NULL;
 }

 static void lfree(struct flist *a)
 {
 	if (a) {
 		free(a->base);
 		free(a);
 	}
 }

 static Py_ssize_t lsize(struct flist *a)
 {
 	return a->tail - a->head;
 }

 /* move hunks in source that are less cut to dest, compensating
    for changes in offset. the last hunk may be split if necessary.
 */
 static int gather(struct flist *dest, struct flist *src, int cut, int offset)
 {
 	struct frag *d = dest->tail, *s = src->head;
 	int postend, c, l;

 	while (s != src->tail) {
 		if (s->start + offset >= cut)
 			break; /* we've gone far enough */

 		postend = offset + s->start + s->len;
 		if (postend <= cut) {
 			/* save this hunk */
 			offset += s->start + s->len - s->end;
 			*d++ = *s++;
 		}
 		else {
 			/* break up this hunk */
 			c = cut - offset;
 			if (s->end < c)
 				c = s->end;
 			l = cut - offset - s->start;
 			if (s->len < l)
 				l = s->len;

 			offset += s->start + l - c;

 			d->start = s->start;
 			d->end = c;
 			d->len = l;
 			d->data = s->data;
 			d++;
 			s->start = c;
 			s->len = s->len - l;
 			s->data = s->data + l;

 			break;
 		}
 	}

 	dest->tail = d;
 	src->head = s;
 	return offset;
 }

 /* like gather, but with no output list */
 static int discard(struct flist *src, int cut, int offset)
 {
 	struct frag *s = src->head;
 	int postend, c, l;

 	while (s != src->tail) {
 		if (s->start + offset >= cut)
 			break;

 		postend = offset + s->start + s->len;
 		if (postend <= cut) {
 			offset += s->start + s->len - s->end;
 			s++;
 		}
 		else {
 			c = cut - offset;
 			if (s->end < c)
 				c = s->end;
 			l = cut - offset - s->start;
 			if (s->len < l)
 				l = s->len;

 			offset += s->start + l - c;
 			s->start = c;
 			s->len = s->len - l;
 			s->data = s->data + l;

 			break;
 		}
 	}

 	src->head = s;
 	return offset;
 }

 /* combine hunk lists a and b, while adjusting b for offset changes in a/
    this deletes a and b and returns the resultant list. */
 static struct flist *combine(struct flist *a, struct flist *b)
 {
 	struct flist *c = NULL;
 	struct frag *bh, *ct;
 	int offset = 0, post;

 	if (a && b)
 		c = lalloc((lsize(a) + lsize(b)) * 2);

 	if (c) {

 		for (bh = b->head; bh != b->tail; bh++) {
 			/* save old hunks */
 			offset = gather(c, a, bh->start, offset);

 			/* discard replaced hunks */
 			post = discard(a, bh->end, offset);

 			/* insert new hunk */
 			ct = c->tail;
 			ct->start = bh->start - offset;
 			ct->end = bh->end - post;
 			ct->len = bh->len;
 			ct->data = bh->data;
 			c->tail++;
 			offset = post;
 		}

 		/* hold on to tail from a */
 		memcpy(c->tail, a->head, sizeof(struct frag) * lsize(a));
 		c->tail += lsize(a);
 	}

 	lfree(a);
 	lfree(b);
 	return c;
 }

 /* decode a binary patch into a hunk list */
 static struct flist *decode(const char *bin, Py_ssize_t len)
 {
 	struct flist *l;
 	struct frag *lt;
 	const char *data = bin + 12, *end = bin + len;

 	/* assume worst case size, we won't have many of these lists */
 	l = lalloc(len / 12);
 	if (!l)
 		return NULL;

 	lt = l->tail;

 	while (data <= end) {
 		lt->start = getbe32(bin);
 		lt->end = getbe32(bin + 4);
 		lt->len = getbe32(bin + 8);
 		if (lt->start > lt->end)
 			break; /* sanity check */
 		bin = data + lt->len;
 		if (bin < data)
 			break; /* big data + big (bogus) len can wrap around */
 		lt->data = data;
 		data = bin + 12;
 		lt++;
 	}

 	if (bin != end) {
 		if (!PyErr_Occurred())
 			PyErr_SetString(mpatch_Error, "patch cannot be decoded");
 		lfree(l);
 		return NULL;
 	}

 	l->tail = lt;
 	return l;
 }

 /* calculate the size of resultant text */
 static Py_ssize_t calcsize(Py_ssize_t len, struct flist *l)
 {
 	Py_ssize_t outlen = 0, last = 0;
 	struct frag *f = l->head;

 	while (f != l->tail) {
 		if (f->start < last || f->end > len) {
 			if (!PyErr_Occurred())
 				PyErr_SetString(mpatch_Error,
 				                "invalid patch");
 			return -1;
 		}
 		outlen += f->start - last;
 		last = f->end;
 		outlen += f->len;
 		f++;
 	}

 	outlen += len - last;
 	return outlen;
 }

 static int apply(char *buf, const char *orig, Py_ssize_t len, struct flist *l)
 {
 	struct frag *f = l->head;
 	int last = 0;
 	char *p = buf;

 	while (f != l->tail) {
 		if (f->start < last || f->end > len) {
 			if (!PyErr_Occurred())
 				PyErr_SetString(mpatch_Error,
 				                "invalid patch");
 			return 0;
 		}
 		memcpy(p, orig + last, f->start - last);
 		p += f->start - last;
 		memcpy(p, f->data, f->len);
 		last = f->end;
 		p += f->len;
 		f++;
 	}
 	memcpy(p, orig + last, len - last);
 	return 1;
 }

 /* recursively generate a patch of all bins between start and end */
 static struct flist *fold(PyObject *bins, Py_ssize_t start, Py_ssize_t end)
 {
 	Py_ssize_t len, blen;
 	const char *buffer;

 	if (start + 1 == end) {
 		/* trivial case, output a decoded list */
 		PyObject *tmp = PyList_GetItem(bins, start);
 		if (!tmp)
 			return NULL;
 		if (PyObject_AsCharBuffer(tmp, &buffer, &blen))
 			return NULL;
 		return decode(buffer, blen);
 	}

 	/* divide and conquer, memory management is elsewhere */
 	len = (end - start) / 2;
 	return combine(fold(bins, start, start + len),
 		       fold(bins, start + len, end));
 }

 static PyObject *
 patches(PyObject *self, PyObject *args)
 {
 	PyObject *text, *bins, *result;
 	struct flist *patch;
 	const char *in;
 	char *out;
 	Py_ssize_t len, outlen, inlen;

 	if (!PyArg_ParseTuple(args, "OO:mpatch", &text, &bins))
 		return NULL;

 	len = PyList_Size(bins);
 	if (!len) {
 		/* nothing to do */
 		Py_INCREF(text);
 		return text;
 	}

 	if (PyObject_AsCharBuffer(text, &in, &inlen))
 		return NULL;

 	patch = fold(bins, 0, len);
 	if (!patch)
 		return NULL;

 	outlen = calcsize(inlen, patch);
 	if (outlen < 0) {
 		result = NULL;
 		goto cleanup;
 	}
 	result = PyBytes_FromStringAndSize(NULL, outlen);
 	if (!result) {
 		result = NULL;
 		goto cleanup;
 	}
 	out = PyBytes_AsString(result);
 	if (!apply(out, in, inlen, patch)) {
 		Py_DECREF(result);
 		result = NULL;
 	}
 cleanup:
 	lfree(patch);
 	return result;
 }

 /* calculate size of a patched file directly */
 static PyObject *
 patchedsize(PyObject *self, PyObject *args)
 {
 	long orig, start, end, len, outlen = 0, last = 0;
 	Py_ssize_t patchlen;
 	char *bin, *binend, *data;

 	if (!PyArg_ParseTuple(args, "ls#", &orig, &bin, &patchlen))
 		return NULL;

 	binend = bin + patchlen;
 	data = bin + 12;

 	while (data <= binend) {
 		start = getbe32(bin);
 		end = getbe32(bin + 4);
 		len = getbe32(bin + 8);
 		if (start > end)
 			break; /* sanity check */
 		bin = data + len;
 		if (bin < data)
 			break; /* big data + big (bogus) len can wrap around */
 		data = bin + 12;
 		outlen += start - last;
 		last = end;
 		outlen += len;
 	}

 	if (bin != binend) {
 		if (!PyErr_Occurred())
 			PyErr_SetString(mpatch_Error, "patch cannot be decoded");
 		return NULL;
 	}

 	outlen += orig - last;
 	return Py_BuildValue("l", outlen);
 }

 static PyMethodDef methods[] = {
 	{"patches", patches, METH_VARARGS, "apply a series of patches\n"},
 	{"patchedsize", patchedsize, METH_VARARGS, "calculed patched size\n"},
 	{NULL, NULL}
 };

 #ifdef IS_PY3K
 static struct PyModuleDef mpatch_module = {
 	PyModuleDef_HEAD_INIT,
 	"mpatch",
 	mpatch_doc,
 	-1,
 	methods
 };

 PyMODINIT_FUNC PyInit_mpatch(void)
 {
 	PyObject *m;

 	m = PyModule_Create(&mpatch_module);
 	if (m == NULL)
 		return NULL;

 	mpatch_Error = PyErr_NewException("mpatch.mpatchError", NULL, NULL);
 	Py_INCREF(mpatch_Error);
 	PyModule_AddObject(m, "mpatchError", mpatch_Error);

 	return m;
 }
 #else
 PyMODINIT_FUNC
 initmpatch(void)
 {
 	Py_InitModule3("mpatch", methods, mpatch_doc);
 	mpatch_Error = PyErr_NewException("mpatch.mpatchError", NULL, NULL);
 }
 #endif
	/*
	mpatch.c - efficient binary patching for Mercurial

	This implements a patch algorithm that's O(m + nlog n) where m is the
	size of the output and n is the number of patches.

	Given a list of binary patches, it unpacks each into a hunk list,
	then combines the hunk lists with a treewise recursion to form a
	single hunk list. This hunk list is then applied to the original
	text.

	The text (or binary) fragments are copied directly from their source
	Python objects into a preallocated output string to avoid the
	allocation of intermediate Python objects. Working memory is about 2x
	the total number of hunks.

	Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>

	This software may be used and distributed according to the terms
	of the GNU General Public License, incorporated herein by reference.
	*/

	#define PY_SSIZE_T_CLEAN
	#include <Python.h>
	#include <stdlib.h>
	#include <string.h>

	#include "util.h"

	static char mpatch_doc[] = "Efficient binary patching.";
	static PyObject *mpatch_Error;

	struct frag {
	int start, end, len;
	const char *data;
	};

	struct flist {
	struct frag base, head, *tail;
	};

	static struct flist *lalloc(Py_ssize_t size)
	{
	struct flist *a = NULL;

	if (size < 1)
	size = 1;

	a = (struct flist *)malloc(sizeof(struct flist));
	if (a) {
	a->base = (struct frag )malloc(sizeof(struct frag) size);
	if (a->base) {
	a->head = a->tail = a->base;
	return a;
	}
	free(a);
	a = NULL;
	}
	if (!PyErr_Occurred())
	PyErr_NoMemory();
	return NULL;
	}

	static void lfree(struct flist *a)
	{
	if (a) {
	free(a->base);
	free(a);
	}
	}

	static Py_ssize_t lsize(struct flist *a)
	{
	return a->tail - a->head;
	}

	/* move hunks in source that are less cut to dest, compensating
	for changes in offset. the last hunk may be split if necessary.
	*/
	static int gather(struct flist dest, struct flist src, int cut, int offset)
	{
	struct frag d = dest->tail, s = src->head;
	int postend, c, l;

	while (s != src->tail) {
	if (s->start + offset >= cut)
	break; /* we've gone far enough */

	postend = offset + s->start + s->len;
	if (postend <= cut) {
	/* save this hunk */
	offset += s->start + s->len - s->end;
	d++ = s++;
	}
	else {
	/* break up this hunk */
	c = cut - offset;
	if (s->end < c)
	c = s->end;
	l = cut - offset - s->start;
	if (s->len < l)
	l = s->len;

	offset += s->start + l - c;

	d->start = s->start;
	d->end = c;
	d->len = l;
	d->data = s->data;
	d++;
	s->start = c;
	s->len = s->len - l;
	s->data = s->data + l;

	break;
	}
	}

	dest->tail = d;
	src->head = s;
	return offset;
	}

	/* like gather, but with no output list */
	static int discard(struct flist *src, int cut, int offset)
	{
	struct frag *s = src->head;
	int postend, c, l;

	while (s != src->tail) {
	if (s->start + offset >= cut)
	break;

	postend = offset + s->start + s->len;
	if (postend <= cut) {
	offset += s->start + s->len - s->end;
	s++;
	}
	else {
	c = cut - offset;
	if (s->end < c)
	c = s->end;
	l = cut - offset - s->start;
	if (s->len < l)
	l = s->len;

	offset += s->start + l - c;
	s->start = c;
	s->len = s->len - l;
	s->data = s->data + l;

	break;
	}
	}

	src->head = s;
	return offset;
	}

	/* combine hunk lists a and b, while adjusting b for offset changes in a/
	this deletes a and b and returns the resultant list. */
	static struct flist combine(struct flist a, struct flist *b)
	{
	struct flist *c = NULL;
	struct frag bh, ct;
	int offset = 0, post;

	if (a && b)
	c = lalloc((lsize(a) + lsize(b)) * 2);

	if (c) {

	for (bh = b->head; bh != b->tail; bh++) {
	/* save old hunks */
	offset = gather(c, a, bh->start, offset);

	/* discard replaced hunks */
	post = discard(a, bh->end, offset);

	/* insert new hunk */
	ct = c->tail;
	ct->start = bh->start - offset;
	ct->end = bh->end - post;
	ct->len = bh->len;
	ct->data = bh->data;
	c->tail++;
	offset = post;
	}

	/* hold on to tail from a */
	memcpy(c->tail, a->head, sizeof(struct frag) * lsize(a));
	c->tail += lsize(a);
	}

	lfree(a);
	lfree(b);
	return c;
	}

	/* decode a binary patch into a hunk list */
	static struct flist decode(const char bin, Py_ssize_t len)
	{
	struct flist *l;
	struct frag *lt;
	const char data = bin + 12, end = bin + len;

	/* assume worst case size, we won't have many of these lists */
	l = lalloc(len / 12);
	if (!l)
	return NULL;

	lt = l->tail;

	while (data <= end) {
	lt->start = getbe32(bin);
	lt->end = getbe32(bin + 4);
	lt->len = getbe32(bin + 8);
	if (lt->start > lt->end)
	break; /* sanity check */
	bin = data + lt->len;
	if (bin < data)
	break; /* big data + big (bogus) len can wrap around */
	lt->data = data;
	data = bin + 12;
	lt++;
	}

	if (bin != end) {
	if (!PyErr_Occurred())
	PyErr_SetString(mpatch_Error, "patch cannot be decoded");
	lfree(l);
	return NULL;
	}

	l->tail = lt;
	return l;
	}

	/* calculate the size of resultant text */
	static Py_ssize_t calcsize(Py_ssize_t len, struct flist *l)
	{
	Py_ssize_t outlen = 0, last = 0;
	struct frag *f = l->head;

	while (f != l->tail) {
	if (f->start < last \|\| f->end > len) {
	if (!PyErr_Occurred())
	PyErr_SetString(mpatch_Error,
	"invalid patch");
	return -1;
	}
	outlen += f->start - last;
	last = f->end;
	outlen += f->len;
	f++;
	}

	outlen += len - last;
	return outlen;
	}

	static int apply(char buf, const char orig, Py_ssize_t len, struct flist *l)
	{
	struct frag *f = l->head;
	int last = 0;
	char *p = buf;

	while (f != l->tail) {
	if (f->start < last \|\| f->end > len) {
	if (!PyErr_Occurred())
	PyErr_SetString(mpatch_Error,
	"invalid patch");
	return 0;
	}
	memcpy(p, orig + last, f->start - last);
	p += f->start - last;
	memcpy(p, f->data, f->len);
	last = f->end;
	p += f->len;
	f++;
	}
	memcpy(p, orig + last, len - last);
	return 1;
	}

	/* recursively generate a patch of all bins between start and end */
	static struct flist fold(PyObject bins, Py_ssize_t start, Py_ssize_t end)
	{
	Py_ssize_t len, blen;
	const char *buffer;

	if (start + 1 == end) {
	/* trivial case, output a decoded list */
	PyObject *tmp = PyList_GetItem(bins, start);
	if (!tmp)
	return NULL;
	if (PyObject_AsCharBuffer(tmp, &buffer, &blen))
	return NULL;
	return decode(buffer, blen);
	}

	/* divide and conquer, memory management is elsewhere */
	len = (end - start) / 2;
	return combine(fold(bins, start, start + len),
	fold(bins, start + len, end));
	}

	static PyObject *
	patches(PyObject self, PyObject args)
	{
	PyObject text, bins, *result;
	struct flist *patch;
	const char *in;
	char *out;
	Py_ssize_t len, outlen, inlen;

	if (!PyArg_ParseTuple(args, "OO:mpatch", &text, &bins))
	return NULL;

	len = PyList_Size(bins);
	if (!len) {
	/* nothing to do */
	Py_INCREF(text);
	return text;
	}

	if (PyObject_AsCharBuffer(text, &in, &inlen))
	return NULL;

	patch = fold(bins, 0, len);
	if (!patch)
	return NULL;

	outlen = calcsize(inlen, patch);
	if (outlen < 0) {
	result = NULL;
	goto cleanup;
	}
	result = PyBytes_FromStringAndSize(NULL, outlen);
	if (!result) {
	result = NULL;
	goto cleanup;
	}
	out = PyBytes_AsString(result);
	if (!apply(out, in, inlen, patch)) {
	Py_DECREF(result);
	result = NULL;
	}
	cleanup:
	lfree(patch);
	return result;
	}

	/* calculate size of a patched file directly */
	static PyObject *
	patchedsize(PyObject self, PyObject args)
	{
	long orig, start, end, len, outlen = 0, last = 0;
	Py_ssize_t patchlen;
	char bin, binend, *data;

	if (!PyArg_ParseTuple(args, "ls#", &orig, &bin, &patchlen))
	return NULL;

	binend = bin + patchlen;
	data = bin + 12;

	while (data <= binend) {
	start = getbe32(bin);
	end = getbe32(bin + 4);
	len = getbe32(bin + 8);
	if (start > end)
	break; /* sanity check */
	bin = data + len;
	if (bin < data)
	break; /* big data + big (bogus) len can wrap around */
	data = bin + 12;
	outlen += start - last;
	last = end;
	outlen += len;
	}

	if (bin != binend) {
	if (!PyErr_Occurred())
	PyErr_SetString(mpatch_Error, "patch cannot be decoded");
	return NULL;
	}

	outlen += orig - last;
	return Py_BuildValue("l", outlen);
	}

	static PyMethodDef methods[] = {
	{"patches", patches, METH_VARARGS, "apply a series of patches\n"},
	{"patchedsize", patchedsize, METH_VARARGS, "calculed patched size\n"},
	{NULL, NULL}
	};

	#ifdef IS_PY3K
	static struct PyModuleDef mpatch_module = {
	PyModuleDef_HEAD_INIT,
	"mpatch",
	mpatch_doc,
	-1,
	methods
	};

	PyMODINIT_FUNC PyInit_mpatch(void)
	{
	PyObject *m;

	m = PyModule_Create(&mpatch_module);
	if (m == NULL)
	return NULL;

	mpatch_Error = PyErr_NewException("mpatch.mpatchError", NULL, NULL);
	Py_INCREF(mpatch_Error);
	PyModule_AddObject(m, "mpatchError", mpatch_Error);

	return m;
	}
	#else
	PyMODINIT_FUNC
	initmpatch(void)
	{
	Py_InitModule3("mpatch", methods, mpatch_doc);
	mpatch_Error = PyErr_NewException("mpatch.mpatchError", NULL, NULL);
	}
	#endif