return 0;
}
+/*
+ * Trim down common substring at the end of the buffers,
+ * but leave at least ctx lines at the end.
+ */
+static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
+{
+ const int blk = 1024;
+ long trimmed = 0, recovered = 0;
+ char *ap = a->ptr + a->size;
+ char *bp = b->ptr + b->size;
+ long smaller = (a->size < b->size) ? a->size : b->size;
+
+ if (ctx)
+ return;
+
+ while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
+ trimmed += blk;
+ ap -= blk;
+ bp -= blk;
+ }
+
+ while (recovered < trimmed)
+ if (ap[recovered++] == '\n')
+ break;
+ a->size -= trimmed - recovered;
+ b->size -= trimmed - recovered;
+}
+
+int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
+{
+ mmfile_t a = *mf1;
+ mmfile_t b = *mf2;
+
+ trim_common_tail(&a, &b, xecfg->ctxlen);
+
+ return xdl_diff(&a, &b, xpp, xecfg, xecb);
+}
+
int read_mmfile(mmfile_t *ptr, const char *filename)
{
struct stat st;