void *xdl_mmfile_writeallocate(mmfile_t *mmf, long size) {
long bsize;
mmblock_t *wcur;
char *blk;
if (!(wcur = mmf->wcur) || wcur->size + size > wcur->bsize) {
bsize = XDL_MAX(mmf->bsize, size);
if (!(wcur = (mmblock_t *) malloc(sizeof(mmblock_t) + bsize))) {
return NULL;
}
wcur->size = 0;
wcur->bsize = bsize;
wcur->next = NULL;
if (!mmf->head)
mmf->head = wcur;
if (mmf->tail)
mmf->tail->next = wcur;
mmf->tail = wcur;
mmf->wcur = wcur;
}
blk = (char *) wcur + sizeof(mmblock_t) + wcur->size;
wcur->size += size;
mmf->fsize += size;
return blk;
}
long xdl_write_mmfile(mmfile_t *mmf, void const *data, long size) {
long wsize, bsize, csize;
mmblock_t *wcur;
for (wsize = 0; wsize < size;) {
if (!(wcur = mmf->wcur) || wcur->size == wcur->bsize ||
(mmf->flags & XDL_MMF_ATOMIC && wcur->size + size > wcur->bsize)) {
bsize = XDL_MAX(mmf->bsize, size);
if (!(wcur = (mmblock_t *) malloc(sizeof(mmblock_t) + bsize))) {
return wsize;
}
wcur->size = 0;
wcur->bsize = bsize;
wcur->next = NULL;
if (!mmf->head)
mmf->head = wcur;
if (mmf->tail)
mmf->tail->next = wcur;
mmf->tail = wcur;
mmf->wcur = wcur;
}
csize = XDL_MIN(size - wsize, wcur->bsize - wcur->size);
memcpy((char *) wcur + sizeof(mmblock_t) + wcur->size,
(char const *) data + wsize, csize);
wsize += csize;
wcur->size += csize;
mmf->fsize += csize;
}
return size;
}
static int process_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
xdemitconf_t const *xecfg)
{
long s1, s2, same, p_next, t_next;
xdchange_t *xch, *xche;
struct xdiff_emit_hunk_state *state = ecb->priv;
xdiff_emit_hunk_consume_fn fn = state->consume;
void *consume_callback_data = state->consume_callback_data;
for (xch = xscr; xch; xch = xche->next) {
xche = xdl_get_hunk(xch, xecfg);
s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
same = s2 + XDL_MAX(xch->i1 - s1, 0);
p_next = xche->i1 + xche->chg1;
t_next = xche->i2 + xche->chg2;
fn(consume_callback_data, same, p_next, t_next);
}
return 0;
}
int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
xdemitconf_t const *xecfg) {
long s1, s2, e1, e2, lctx;
xdchange_t *xch, *xche;
long funclineprev = -1;
struct func_line func_line = { 0 };
if (xecfg->flags & XDL_EMIT_COMMON)
return xdl_emit_common(xe, xscr, ecb, xecfg);
for (xch = xscr; xch; xch = xche->next) {
xche = xdl_get_hunk(xch, xecfg);
s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
long fs1 = get_func_line(xe, xecfg, NULL, xch->i1, -1);
if (fs1 < 0)
fs1 = 0;
if (fs1 < s1) {
s2 -= s1 - fs1;
s1 = fs1;
}
}
again:
lctx = xecfg->ctxlen;
lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
e1 = xche->i1 + xche->chg1 + lctx;
e2 = xche->i2 + xche->chg2 + lctx;
if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
long fe1 = get_func_line(xe, xecfg, NULL,
xche->i1 + xche->chg1,
xe->xdf1.nrec);
if (fe1 < 0)
fe1 = xe->xdf1.nrec;
if (fe1 > e1) {
e2 += fe1 - e1;
e1 = fe1;
}
/*
* Overlap with next change? Then include it
* in the current hunk and start over to find
* its new end.
*/
if (xche->next) {
long l = xche->next->i1;
if (l <= e1 ||
get_func_line(xe, xecfg, NULL, l, e1) < 0) {
xche = xche->next;
goto again;
}
}
}
/*
* Emit current hunk header.
*/
if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
get_func_line(xe, xecfg, &func_line,
s1 - 1, funclineprev);
funclineprev = s1 - 1;
}
if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
func_line.buf, func_line.len, ecb) < 0)
return -1;
/*
* Emit pre-context.
*/
for (; s2 < xch->i2; s2++)
if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
return -1;
for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
/*
* Merge previous with current change atom.
*/
for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
return -1;
/*
* Removes lines from the first file.
*/
for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
return -1;
/*
* Adds lines from the second file.
*/
for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
return -1;
if (xch == xche)
break;
s1 = xch->i1 + xch->chg1;
s2 = xch->i2 + xch->chg2;
}
/*
* Emit post-context.
*/
for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
return -1;
}
return 0;
}
int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
xdemitconf_t const *xecfg) {
long s1, s2, e1, e2, lctx;
xdchange_t *xch, *xche;
char funcbuf[80];
long funclen = 0;
find_func_t ff = xecfg->find_func ? xecfg->find_func : def_ff;
if (xecfg->flags & XDL_EMIT_COMMON)
return xdl_emit_common(xe, xscr, ecb, xecfg);
for (xch = xche = xscr; xch; xch = xche->next) {
xche = xdl_get_hunk(xch, xecfg);
s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
lctx = xecfg->ctxlen;
lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
e1 = xche->i1 + xche->chg1 + lctx;
e2 = xche->i2 + xche->chg2 + lctx;
/*
* Emit current hunk header.
*/
if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
xdl_find_func(&xe->xdf1, s1, funcbuf,
sizeof(funcbuf), &funclen,
ff, xecfg->find_func_priv);
}
if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
funcbuf, funclen, ecb) < 0)
return -1;
/*
* Emit pre-context.
*/
for (; s1 < xch->i1; s1++)
if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
return -1;
for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
/*
* Merge previous with current change atom.
*/
for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
return -1;
/*
* Removes lines from the first file.
*/
for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
return -1;
/*
* Adds lines from the second file.
*/
for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
return -1;
if (xch == xche)
break;
s1 = xch->i1 + xch->chg1;
s2 = xch->i2 + xch->chg2;
}
/*
* Emit post-context.
*/
for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
return -1;
}
return 0;
}
/*
* See "An O(ND) Difference Algorithm and its Variations", by Eugene Myers.
* Basically considers a "box" (off1, off2, lim1, lim2) and scan from both
* the forward diagonal starting from (off1, off2) and the backward diagonal
* starting from (lim1, lim2). If the K values on the same diagonal crosses
* returns the furthest point of reach. We might end up having to expensive
* cases using this algorithm is full, so a little bit of heuristic is needed
* to cut the search and to return a suboptimal point.
*/
static long xdl_split(unsigned long const *ha1, long off1, long lim1,
unsigned long const *ha2, long off2, long lim2,
long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl,
xdalgoenv_t *xenv) {
long dmin = off1 - lim2, dmax = lim1 - off2;
long fmid = off1 - off2, bmid = lim1 - lim2;
long odd = (fmid - bmid) & 1;
long fmin = fmid, fmax = fmid;
long bmin = bmid, bmax = bmid;
long ec, d, i1, i2, prev1, best, dd, v, k;
/*
* Set initial diagonal values for both forward and backward path.
*/
kvdf[fmid] = off1;
kvdb[bmid] = lim1;
for (ec = 1;; ec++) {
int got_snake = 0;
/*
* We need to extent the diagonal "domain" by one. If the next
* values exits the box boundaries we need to change it in the
* opposite direction because (max - min) must be a power of two.
* Also we initialize the external K value to -1 so that we can
* avoid extra conditions check inside the core loop.
*/
if (fmin > dmin)
kvdf[--fmin - 1] = -1;
else
++fmin;
if (fmax < dmax)
kvdf[++fmax + 1] = -1;
else
--fmax;
for (d = fmax; d >= fmin; d -= 2) {
if (kvdf[d - 1] >= kvdf[d + 1])
i1 = kvdf[d - 1] + 1;
else
i1 = kvdf[d + 1];
prev1 = i1;
i2 = i1 - d;
for (; i1 < lim1 && i2 < lim2 && ha1[i1] == ha2[i2]; i1++, i2++);
if (i1 - prev1 > xenv->snake_cnt)
got_snake = 1;
kvdf[d] = i1;
if (odd && bmin <= d && d <= bmax && kvdb[d] <= i1) {
spl->i1 = i1;
spl->i2 = i2;
spl->min_lo = spl->min_hi = 1;
return ec;
}
}
/*
* We need to extent the diagonal "domain" by one. If the next
* values exits the box boundaries we need to change it in the
* opposite direction because (max - min) must be a power of two.
* Also we initialize the external K value to -1 so that we can
* avoid extra conditions check inside the core loop.
*/
if (bmin > dmin)
kvdb[--bmin - 1] = XDL_LINE_MAX;
else
++bmin;
if (bmax < dmax)
kvdb[++bmax + 1] = XDL_LINE_MAX;
else
--bmax;
for (d = bmax; d >= bmin; d -= 2) {
if (kvdb[d - 1] < kvdb[d + 1])
i1 = kvdb[d - 1];
else
i1 = kvdb[d + 1] - 1;
prev1 = i1;
i2 = i1 - d;
for (; i1 > off1 && i2 > off2 && ha1[i1 - 1] == ha2[i2 - 1]; i1--, i2--);
if (prev1 - i1 > xenv->snake_cnt)
got_snake = 1;
kvdb[d] = i1;
if (!odd && fmin <= d && d <= fmax && i1 <= kvdf[d]) {
spl->i1 = i1;
spl->i2 = i2;
spl->min_lo = spl->min_hi = 1;
return ec;
}
}
if (need_min)
continue;
/*
* If the edit cost is above the heuristic trigger and if
* we got a good snake, we sample current diagonals to see
* if some of the, have reached an "interesting" path. Our
* measure is a function of the distance from the diagonal
* corner (i1 + i2) penalized with the distance from the
* mid diagonal itself. If this value is above the current
* edit cost times a magic factor (XDL_K_HEUR) we consider
* it interesting.
*/
if (got_snake && ec > xenv->heur_min) {
for (best = 0, d = fmax; d >= fmin; d -= 2) {
dd = d > fmid ? d - fmid: fmid - d;
i1 = kvdf[d];
i2 = i1 - d;
v = (i1 - off1) + (i2 - off2) - dd;
if (v > XDL_K_HEUR * ec && v > best &&
off1 + xenv->snake_cnt <= i1 && i1 < lim1 &&
off2 + xenv->snake_cnt <= i2 && i2 < lim2) {
for (k = 1; ha1[i1 - k] == ha2[i2 - k]; k++)
if (k == xenv->snake_cnt) {
best = v;
spl->i1 = i1;
spl->i2 = i2;
break;
}
}
}
if (best > 0) {
spl->min_lo = 1;
spl->min_hi = 0;
return ec;
}
for (best = 0, d = bmax; d >= bmin; d -= 2) {
dd = d > bmid ? d - bmid: bmid - d;
i1 = kvdb[d];
i2 = i1 - d;
v = (lim1 - i1) + (lim2 - i2) - dd;
if (v > XDL_K_HEUR * ec && v > best &&
off1 < i1 && i1 <= lim1 - xenv->snake_cnt &&
off2 < i2 && i2 <= lim2 - xenv->snake_cnt) {
for (k = 0; ha1[i1 + k] == ha2[i2 + k]; k++)
if (k == xenv->snake_cnt - 1) {
best = v;
spl->i1 = i1;
spl->i2 = i2;
break;
}
}
}
if (best > 0) {
spl->min_lo = 0;
spl->min_hi = 1;
return ec;
}
}
/*
* Enough is enough. We spent too much time here and now we collect
* the furthest reaching path using the (i1 + i2) measure.
*/
if (ec >= xenv->mxcost) {
long fbest, fbest1, bbest, bbest1;
fbest = fbest1 = -1;
for (d = fmax; d >= fmin; d -= 2) {
i1 = XDL_MIN(kvdf[d], lim1);
i2 = i1 - d;
if (lim2 < i2)
i1 = lim2 + d, i2 = lim2;
if (fbest < i1 + i2) {
fbest = i1 + i2;
fbest1 = i1;
}
}
bbest = bbest1 = XDL_LINE_MAX;
for (d = bmax; d >= bmin; d -= 2) {
i1 = XDL_MAX(off1, kvdb[d]);
i2 = i1 - d;
if (i2 < off2)
i1 = off2 + d, i2 = off2;
if (i1 + i2 < bbest) {
bbest = i1 + i2;
bbest1 = i1;
}
}
if ((lim1 + lim2) - bbest < fbest - (off1 + off2)) {
spl->i1 = fbest1;
spl->i2 = fbest - fbest1;
spl->min_lo = 1;
spl->min_hi = 0;
} else {
spl->i1 = bbest1;
spl->i2 = bbest - bbest1;
spl->min_lo = 0;
spl->min_hi = 1;
}
return ec;
}
}
}
