bdiff: don't check border condition in loop This is pretty much a copy of d500ddae7494, just to a different loop. The condition `p == plast` (`plast == a + len - 1`) was only true on the final iteration of the loop. So it was wasteful to check for it on every iteration. We decrease the iteration count by 1 and add an explicit check for `p == plast` after the loop. Again, we see modest wins. From the mozilla-unified repository: $ perfbdiff -m 3041e4d59df2 ! wall 0.035502 comb 0.040000 user 0.040000 sys 0.000000 (best of 100) ! wall 0.030480 comb 0.030000 user 0.030000 sys 0.000000 (best of 100) $ perfbdiff 0e9928989e9c --alldata --count 100 ! wall 4.097394 comb 4.100000 user 4.100000 sys 0.000000 (best of 3) ! wall 3.597798 comb 3.600000 user 3.600000 sys 0.000000 (best of 3) The 2nd example throws a total of ~3.3GB of data at bdiff. This change increases the throughput from ~811 MB/s to ~924 MB/s.

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#ifndef _HG_BDIFF_H_

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#define _HG_BDIFF_H_

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struct bdiff_line {

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	int hash, n, e;

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	ssize_t len;

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	const char *l;

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};

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struct bdiff_hunk;

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struct bdiff_hunk {

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	int a1, a2, b1, b2;

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	struct bdiff_hunk *next;

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};

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int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);

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int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,

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	struct bdiff_hunk *base);

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void bdiff_freehunks(struct bdiff_hunk *l);

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#endif