merge: do early copy to deal with issue636
Without copies/renames, merges source names are 1:1 with their
targets. Copies and renames introduce the possibility that there will
be two merges with the same input but different output. By doing the
copy to the destination name before the merge, the actual merge
becomes 1:1 again, and no source is the input to two different merges.
- add a preliminary scan to applyupdates to do copies
- for the merge action, pass the old name (for finding ancestors) and
the new name (for input to the merge) to filemerge
- eliminate the old post-merge copy
- lookup file contents from new name in filemerge
- pass new name to external merge helper
- report merge failure at new name
- add a test
/*
base85 codec
Copyright 2006 Brendan Cully <brendan@kublai.com>
This software may be used and distributed according to the terms of
the GNU General Public License, incorporated herein by reference.
Largely based on git's implementation
*/
#include <Python.h>
static const char b85chars[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
static char b85dec[256];
static void
b85prep(void)
{
int i;
memset(b85dec, 0, sizeof(b85dec));
for (i = 0; i < sizeof(b85chars); i++)
b85dec[(int)(b85chars[i])] = i + 1;
}
static PyObject *
b85encode(PyObject *self, PyObject *args)
{
const unsigned char *text;
PyObject *out;
char *dst;
int len, olen, i;
unsigned int acc, val, ch;
int pad = 0;
if (!PyArg_ParseTuple(args, "s#|i", &text, &len, &pad))
return NULL;
if (pad)
olen = ((len + 3) / 4 * 5) - 3;
else {
olen = len % 4;
if (olen)
olen++;
olen += len / 4 * 5;
}
if (!(out = PyString_FromStringAndSize(NULL, olen + 3)))
return NULL;
dst = PyString_AS_STRING(out);
while (len) {
acc = 0;
for (i = 24; i >= 0; i -= 8) {
ch = *text++;
acc |= ch << i;
if (--len == 0)
break;
}
for (i = 4; i >= 0; i--) {
val = acc % 85;
acc /= 85;
dst[i] = b85chars[val];
}
dst += 5;
}
if (!pad)
_PyString_Resize(&out, olen);
return out;
}
static PyObject *
b85decode(PyObject *self, PyObject *args)
{
PyObject *out;
const char *text;
char *dst;
int len, i, j, olen, c, cap;
unsigned int acc;
if (!PyArg_ParseTuple(args, "s#", &text, &len))
return NULL;
olen = len / 5 * 4;
i = len % 5;
if (i)
olen += i - 1;
if (!(out = PyString_FromStringAndSize(NULL, olen)))
return NULL;
dst = PyString_AS_STRING(out);
i = 0;
while (i < len)
{
acc = 0;
cap = len - i - 1;
if (cap > 4)
cap = 4;
for (j = 0; j < cap; i++, j++)
{
c = b85dec[(int)*text++] - 1;
if (c < 0)
return PyErr_Format(PyExc_ValueError, "Bad base85 character at position %d", i);
acc = acc * 85 + c;
}
if (i++ < len)
{
c = b85dec[(int)*text++] - 1;
if (c < 0)
return PyErr_Format(PyExc_ValueError, "Bad base85 character at position %d", i);
/* overflow detection: 0xffffffff == "|NsC0",
* "|NsC" == 0x03030303 */
if (acc > 0x03030303 || (acc *= 85) > 0xffffffff - c)
return PyErr_Format(PyExc_ValueError, "Bad base85 sequence at position %d", i);
acc += c;
}
cap = olen < 4 ? olen : 4;
olen -= cap;
for (j = 0; j < 4 - cap; j++)
acc *= 85;
if (cap && cap < 4)
acc += 0xffffff >> (cap - 1) * 8;
for (j = 0; j < cap; j++)
{
acc = (acc << 8) | (acc >> 24);
*dst++ = acc;
}
}
return out;
}
static char base85_doc[] = "Base85 Data Encoding";
static PyMethodDef methods[] = {
{"b85encode", b85encode, METH_VARARGS,
"Encode text in base85.\n\n"
"If the second parameter is true, pad the result to a multiple of "
"five characters.\n"},
{"b85decode", b85decode, METH_VARARGS, "Decode base85 text.\n"},
{NULL, NULL}
};
PyMODINIT_FUNC initbase85(void)
{
Py_InitModule3("base85", methods, base85_doc);
b85prep();
}