xdiff: do away with xdl_mmfile_next()
[gitweb.git] / xdiff / xprepare.c
index 16890852350cb62bb9f9aec5e52eea8ba46f1192..620fc9a657e2246d3a382c916c2cdd4f820c0c44 100644 (file)
@@ -26,6 +26,8 @@
 #define XDL_KPDIS_RUN 4
 #define XDL_MAX_EQLIMIT 1024
 #define XDL_SIMSCAN_WINDOW 100
+#define XDL_GUESS_NLINES1 256
+#define XDL_GUESS_NLINES2 20
 
 
 typedef struct s_xdlclass {
@@ -64,8 +66,6 @@ static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2);
 
 
 static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) {
-       long i;
-
        cf->flags = flags;
 
        cf->hbits = xdl_hashbits((unsigned int) size);
@@ -80,8 +80,7 @@ static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) {
                xdl_cha_free(&cf->ncha);
                return -1;
        }
-       for (i = 0; i < cf->hsize; i++)
-               cf->rchash[i] = NULL;
+       memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *));
 
        cf->count = 0;
 
@@ -136,7 +135,7 @@ static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned
 static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
                           xdlclassifier_t *cf, xdfile_t *xdf) {
        unsigned int hbits;
-       long i, nrec, hsize, bsize;
+       long nrec, hsize, bsize;
        unsigned long hav;
        char const *blk, *cur, *top, *prev;
        xrecord_t *crec;
@@ -146,96 +145,59 @@ static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
        char *rchg;
        long *rindex;
 
-       if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) {
-
-               return -1;
-       }
-       if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) {
-
-               xdl_cha_free(&xdf->rcha);
-               return -1;
-       }
-
-       hbits = xdl_hashbits((unsigned int) narec);
-       hsize = 1 << hbits;
-       if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) {
-
-               xdl_free(recs);
-               xdl_cha_free(&xdf->rcha);
-               return -1;
+       ha = NULL;
+       rindex = NULL;
+       rchg = NULL;
+       rhash = NULL;
+       recs = NULL;
+
+       if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0)
+               goto abort;
+       if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *))))
+               goto abort;
+
+       if (xpp->flags & XDF_HISTOGRAM_DIFF)
+               hbits = hsize = 0;
+       else {
+               hbits = xdl_hashbits((unsigned int) narec);
+               hsize = 1 << hbits;
+               if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *))))
+                       goto abort;
+               memset(rhash, 0, hsize * sizeof(xrecord_t *));
        }
-       for (i = 0; i < hsize; i++)
-               rhash[i] = NULL;
 
        nrec = 0;
        if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) {
-               for (top = blk + bsize;;) {
-                       if (cur >= top) {
-                               if (!(cur = blk = xdl_mmfile_next(mf, &bsize)))
-                                       break;
-                               top = blk + bsize;
-                       }
+               for (top = blk + bsize; cur < top; ) {
                        prev = cur;
                        hav = xdl_hash_record(&cur, top, xpp->flags);
                        if (nrec >= narec) {
                                narec *= 2;
-                               if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *)))) {
-
-                                       xdl_free(rhash);
-                                       xdl_free(recs);
-                                       xdl_cha_free(&xdf->rcha);
-                                       return -1;
-                               }
+                               if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *))))
+                                       goto abort;
                                recs = rrecs;
                        }
-                       if (!(crec = xdl_cha_alloc(&xdf->rcha))) {
-
-                               xdl_free(rhash);
-                               xdl_free(recs);
-                               xdl_cha_free(&xdf->rcha);
-                               return -1;
-                       }
+                       if (!(crec = xdl_cha_alloc(&xdf->rcha)))
+                               goto abort;
                        crec->ptr = prev;
                        crec->size = (long) (cur - prev);
                        crec->ha = hav;
                        recs[nrec++] = crec;
 
-                       if (xdl_classify_record(cf, rhash, hbits, crec) < 0) {
-
-                               xdl_free(rhash);
-                               xdl_free(recs);
-                               xdl_cha_free(&xdf->rcha);
-                               return -1;
-                       }
+                       if (!(xpp->flags & XDF_HISTOGRAM_DIFF) &&
+                               xdl_classify_record(cf, rhash, hbits, crec) < 0)
+                               goto abort;
                }
        }
 
-       if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) {
-
-               xdl_free(rhash);
-               xdl_free(recs);
-               xdl_cha_free(&xdf->rcha);
-               return -1;
-       }
+       if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char))))
+               goto abort;
        memset(rchg, 0, (nrec + 2) * sizeof(char));
 
-       if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long)))) {
-
-               xdl_free(rchg);
-               xdl_free(rhash);
-               xdl_free(recs);
-               xdl_cha_free(&xdf->rcha);
-               return -1;
-       }
-       if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long)))) {
-
-               xdl_free(rindex);
-               xdl_free(rchg);
-               xdl_free(rhash);
-               xdl_free(recs);
-               xdl_cha_free(&xdf->rcha);
-               return -1;
-       }
+       if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long))))
+               goto abort;
+       if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long))))
+               goto abort;
 
        xdf->nrec = nrec;
        xdf->recs = recs;
@@ -249,6 +211,15 @@ static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
        xdf->dend = nrec - 1;
 
        return 0;
+
+abort:
+       xdl_free(ha);
+       xdl_free(rindex);
+       xdl_free(rchg);
+       xdl_free(rhash);
+       xdl_free(recs);
+       xdl_cha_free(&xdf->rcha);
+       return -1;
 }
 
 
@@ -265,13 +236,23 @@ static void xdl_free_ctx(xdfile_t *xdf) {
 
 int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
                    xdfenv_t *xe) {
-       long enl1, enl2;
+       long enl1, enl2, sample;
        xdlclassifier_t cf;
 
-       enl1 = xdl_guess_lines(mf1) + 1;
-       enl2 = xdl_guess_lines(mf2) + 1;
+       /*
+        * For histogram diff, we can afford a smaller sample size and
+        * thus a poorer estimate of the number of lines, as the hash
+        * table (rhash) won't be filled up/grown. The number of lines
+        * (nrecs) will be updated correctly anyway by
+        * xdl_prepare_ctx().
+        */
+       sample = xpp->flags & XDF_HISTOGRAM_DIFF ? XDL_GUESS_NLINES2 : XDL_GUESS_NLINES1;
+
+       enl1 = xdl_guess_lines(mf1, sample) + 1;
+       enl2 = xdl_guess_lines(mf2, sample) + 1;
 
-       if (xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0) {
+       if (!(xpp->flags & XDF_HISTOGRAM_DIFF) &&
+               xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0) {
 
                return -1;
        }
@@ -288,9 +269,11 @@ int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
                return -1;
        }
 
-       xdl_free_classifier(&cf);
+       if (!(xpp->flags & XDF_HISTOGRAM_DIFF))
+               xdl_free_classifier(&cf);
 
        if (!(xpp->flags & XDF_PATIENCE_DIFF) &&
+                       !(xpp->flags & XDF_HISTOGRAM_DIFF) &&
                        xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) {
 
                xdl_free_ctx(&xe->xdf2);