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104 lines
2.4 KiB
104 lines
2.4 KiB
2 months ago
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/*
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* UCW Library -- Universal Sorter: Two-Way Merge Module
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*
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* (c) 2007 Martin Mares <mj@ucw.cz>
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*
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* This software may be freely distributed and used according to the terms
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* of the GNU Lesser General Public License.
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*/
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static void P(twoway_merge)(struct sort_context *ctx UNUSED, struct sort_bucket **ins, struct sort_bucket **outs)
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{
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struct fastbuf *fin1, *fin2, *fout1, *fout2, *ftmp;
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P(key) kbuf1, kbuf2, kbuf3, kbuf4;
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P(key) *kin1 = &kbuf1, *kprev1 = &kbuf2, *kin2 = &kbuf3, *kprev2 = &kbuf4;
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P(key) *kout = NULL, *ktmp;
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int next1, next2, run1, run2;
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int comp;
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uint run_count = 0;
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fin1 = sbuck_read(ins[0]);
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next1 = P(read_key)(fin1, kin1);
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if (sbuck_have(ins[1]))
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{
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fin2 = sbuck_read(ins[1]);
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next2 = P(read_key)(fin2, kin2);
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}
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else
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{
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fin2 = NULL;
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next2 = 0;
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}
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fout1 = fout2 = NULL;
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run1 = next1, run2 = next2;
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while (next1 || next2)
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{
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if (!run1)
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comp = 1;
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else if (!run2)
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comp = -1;
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else
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comp = P(compare)(kin1, kin2);
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ktmp = (comp <= 0) ? kin1 : kin2;
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if (!kout || !(P(compare)(kout, ktmp) LESS 0))
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{
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SWAP(fout1, fout2, ftmp);
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if (unlikely(!fout1))
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{
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if (!fout2)
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fout1 = sbuck_write(outs[0]);
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else if (outs[1])
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fout1 = sbuck_write(outs[1]);
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else
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fout1 = fout2;
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}
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run_count++;
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}
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#ifdef SORT_ASSERT_UNIQUE
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ASSERT(comp != 0);
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#endif
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if (comp LESS 0)
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{
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P(copy_data)(kin1, fin1, fout1);
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SWAP(kin1, kprev1, ktmp);
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next1 = P(read_key)(fin1, kin1);
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run1 = next1 && (P(compare)(kprev1, kin1) LESS 0);
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kout = kprev1;
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}
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#ifdef SORT_UNIFY
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else if (comp == 0)
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{
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P(key) *mkeys[] = { kin1, kin2 };
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struct fastbuf *mfb[] = { fin1, fin2 };
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P(copy_merged)(mkeys, mfb, 2, fout1);
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SWAP(kin1, kprev1, ktmp);
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next1 = P(read_key)(fin1, kin1);
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run1 = next1 && (P(compare)(kprev1, kin1) LESS 0);
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SWAP(kin2, kprev2, ktmp);
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next2 = P(read_key)(fin2, kin2);
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run2 = next2 && (P(compare)(kprev2, kin2) LESS 0);
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kout = kprev2;
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}
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#endif
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else
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{
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P(copy_data)(kin2, fin2, fout1);
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SWAP(kin2, kprev2, ktmp);
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next2 = P(read_key)(fin2, kin2);
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run2 = next2 && (P(compare)(kprev2, kin2) LESS 0);
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kout = kprev2;
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}
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if (!run1 && !run2)
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{
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run1 = next1;
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run2 = next2;
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}
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}
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if (fout2 && fout2 != fout1)
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outs[1]->runs += run_count / 2;
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if (fout1)
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outs[0]->runs += (run_count+1) / 2;
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}
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