[PATCH 3/8] xdl_change_compact(): rename i to end
- From
Michael Haggerty <mhagger@alum.mit.edu>
- Date
- Aug 3, 2016, 22:00 UTC
- Message-ID
- <625e39916051e2ea5e09e1c0d3c4f6c25e61302d.1470259583.git.mhagger@alum.mit.edu>
- In-Reply-To
- <cover.1470259583.git.mhagger@alum.mit.edu>
Rename i to end, and alternate between using start and end as the indexing variable as appropriate.
Rename ixref to end_matching_other.
Add some more comments.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> --- xdiff/xdiffi.c | 70 ++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 39 insertions(+), 31 deletions(-)
diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c index a0a485c..0f235bc 100644 --- a/xdiff/xdiffi.c +++ b/xdiff/xdiffi.c @@ -414,7 +414,7 @@ static int recs_match(xrecord_t **recs, long ixs, long ix, long flags) } int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { - long i, io, start, ixref, groupsize, nrec = xdf->nrec; + long start, end, io, end_matching_other, groupsize, nrec = xdf->nrec; char *rchg = xdf->rchg, *rchgo = xdfo->rchg; unsigned int blank_lines; xrecord_t **recs = xdf->recs; @@ -424,7 +424,8 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { * change groups for a consistent and pretty diff output. This also * helps in finding joinable change groups and reduce the diff size. */ - for (i = io = 0;;) { + end = io = 0; + while (1) { /* * Find the first changed line in the to-be-compacted file. * We need to keep track of both indexes, so if we find a @@ -434,7 +435,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { * not need index bounding since the array is prepared with * a zero at position -1 and N. */ - for (; i < nrec && !rchg[i]; i++) { + for (start = end; start < nrec && !rchg[start]; start++) { /* skip over any changed lines in the other file... */ while (rchgo[io]) io++; @@ -442,24 +443,29 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { /* ...plus one non-changed line. */ io++; } - if (i == nrec) + if (start == nrec) break; /* - * Record the start of a changed-group in the to-be-compacted file - * and find the end of it, on both to-be-compacted and other file - * indexes (i and io). + * That's the start of a changed-group in the to-be-compacted + * file. Now find its end. */ - start = i++; - - while (rchg[i]) - i++; + end = start + 1; + while (rchg[end]) + end++; while (rchgo[io]) io++; + /* + * Now shift the change up and then down as far as possible in + * each direction. If it bumps into any other changes, merge them. + * If there are any changes in the other file that this change + * could line up with, set end_matching_other to the end position + * of this change that would leave them aligned. + */ do { - groupsize = i - start; + groupsize = end - start; /* * Are there any blank lines that could appear as the last @@ -472,9 +478,9 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { * to the last line of the current change group, shift the * group backward. */ - while (start > 0 && recs_match(recs, start - 1, i - 1, flags)) { + while (start > 0 && recs_match(recs, start - 1, end - 1, flags)) { rchg[--start] = 1; - rchg[--i] = 0; + rchg[--end] = 0; /* * This change might have joined two change groups. @@ -501,13 +507,13 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { * the other file. Record the end-of-group * position: */ - ixref = i; + end_matching_other = end; } else { /* * Otherwise, set a value to signify that there * are no matched changes in the other file: */ - ixref = nrec; + end_matching_other = -1; } /* @@ -515,11 +521,11 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { * of the current change group is equal to the line after * the current change group. */ - while (i < nrec && recs_match(recs, start, i, flags)) { - blank_lines += is_blank_line(recs, i, flags); + while (end < nrec && recs_match(recs, start, end, flags)) { + blank_lines += is_blank_line(recs, end, flags); rchg[start++] = 0; - rchg[i++] = 1; + rchg[end++] = 1; /* * This change might have joined two change @@ -529,29 +535,31 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { * are shifting together with a corresponding * group of changes in the other file. */ - while (rchg[i]) - i++; + while (rchg[end]) + end++; io++; if (rchgo[io]) { - ixref = i; + end_matching_other = end; while (rchgo[io]) io++; } } - } while (groupsize != i - start); + } while (groupsize != end - start); /* * Try to move back the possibly merged group of changes, to match * the recorded position in the other file. */ - while (ixref < i) { - rchg[--start] = 1; - rchg[--i] = 0; + if (end_matching_other != -1) { + while (end_matching_other < end) { + rchg[--start] = 1; + rchg[--end] = 0; - io--; - while (rchgo[io]) io--; + while (rchgo[io]) + io--; + } } /* @@ -564,10 +572,10 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { */ if ((flags & XDF_COMPACTION_HEURISTIC) && blank_lines) { while (start > 0 && - !is_blank_line(recs, i - 1, flags) && - recs_match(recs, start - 1, i - 1, flags)) { + !is_blank_line(recs, end - 1, flags) && + recs_match(recs, start - 1, end - 1, flags)) { rchg[--start] = 1; - rchg[--i] = 0; + rchg[--end] = 0; } } }
-- 2.8.1