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Change diff Implementation to use end indices instead of length

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Having absolute begin and relative lenght was a bit strange to
work with. Rename middle_snake to snake.
This commit is contained in:
Maxime Coste 2017-07-18 12:14:52 +02:00
parent 793c2ed9cf
commit 50fec86749
2 changed files with 39 additions and 25 deletions
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42
src/diff.hh
View File

@ -108,53 +108,55 @@ inline void append_diff(Vector<Diff>& diffs, Diff diff)
} }
template<typename Iterator, typename Equal> template<typename Iterator, typename Equal>
void find_diff_rec(Iterator a, int offA, int lenA, void find_diff_rec(Iterator a, int begA, int endA,
Iterator b, int offB, int lenB, Iterator b, int begB, int endB,
int* V1, int* V2, Equal eq, Vector<Diff>& diffs) int* V1, int* V2, Equal eq, Vector<Diff>& diffs)
{ {
int prefix_len = 0; int prefix_len = 0;
while (lenA > 0 and lenB > 0 and a[offA] == b[offB]) while (begA != endA and begB != endB and a[begA] == b[begB])
++offA, ++offB, --lenA, --lenB, ++prefix_len; ++begA, ++begB, ++prefix_len;
int suffix_len = 0; int suffix_len = 0;
while (lenA != 0 and lenB != 0 and a[offA + lenA - 1] == b[offB + lenB - 1]) while (begA != endA and begB != endB and a[endA-1] == b[endB-1])
--lenA, --lenB, ++suffix_len; --endA, --endB, ++suffix_len;
append_diff(diffs, {Diff::Keep, prefix_len, 0}); append_diff(diffs, {Diff::Keep, prefix_len, 0});
const auto lenA = endA - begA, lenB = endB - begB;
if (lenA == 0) if (lenA == 0)
append_diff(diffs, {Diff::Add, lenB, offB}); append_diff(diffs, {Diff::Add, lenB, begB});
else if (lenB == 0) else if (lenB == 0)
append_diff(diffs, {Diff::Remove, lenA, 0}); append_diff(diffs, {Diff::Remove, lenA, 0});
else else
{ {
auto middle_snake = find_middle_snake(a + offA, lenA, b + offB, lenB, V1, V2, eq); auto snake = find_middle_snake(a + begA, lenA, b + begB, lenB, V1, V2, eq);
kak_assert(middle_snake.u <= lenA and middle_snake.v <= lenB); kak_assert(snake.u <= lenA and snake.v <= lenB);
if (middle_snake.d > 1) if (snake.d > 1)
{ {
find_diff_rec(a, offA, middle_snake.x, find_diff_rec(a, begA, begA + snake.x,
b, offB, middle_snake.y, b, begB, begB + snake.y,
V1, V2, eq, diffs); V1, V2, eq, diffs);
append_diff(diffs, {Diff::Keep, middle_snake.u - middle_snake.x, 0}); append_diff(diffs, {Diff::Keep, snake.u - snake.x, 0});
find_diff_rec(a, offA + middle_snake.u, lenA - middle_snake.u, find_diff_rec(a, begA + snake.u, endA,
b, offB + middle_snake.v, lenB - middle_snake.v, b, begB + snake.v, endB,
V1, V2, eq, diffs); V1, V2, eq, diffs);
} }
else else
{ {
if (middle_snake.d == 1) if (snake.d == 1)
{ {
const int diag = middle_snake.x - (middle_snake.add ? 0 : 1); const int diag = snake.x - (snake.add ? 0 : 1);
append_diff(diffs, {Diff::Keep, diag, 0}); append_diff(diffs, {Diff::Keep, diag, 0});
if (middle_snake.add) if (snake.add)
append_diff(diffs, {Diff::Add, 1, offB + diag}); append_diff(diffs, {Diff::Add, 1, begB + diag});
else else
append_diff(diffs, {Diff::Remove, 1, 0}); append_diff(diffs, {Diff::Remove, 1, 0});
} }
append_diff(diffs, {Diff::Keep, middle_snake.u - middle_snake.x, 0}); append_diff(diffs, {Diff::Keep, snake.u - snake.x, 0});
} }
} }

22
src/unit_tests.cc
View File

@ -30,16 +30,28 @@ UnitTest test_diff{[]()
} }
{ {
StringView s1 = "a?"; auto diff = find_diff("a?", 2, "!", 1);
StringView s2 = "!";
auto diff = find_diff(s1.begin(), (int)s1.length(), s2.begin(), (int)s2.length());
kak_assert(diff.size() == 3 and kak_assert(diff.size() == 3 and
eq(diff[0], {Diff::Remove, 1, 0}) and eq(diff[0], {Diff::Remove, 1, 0}) and
eq(diff[1], {Diff::Add, 1, 0}) and eq(diff[1], {Diff::Add, 1, 0}) and
eq(diff[2], {Diff::Remove, 1, 0})); eq(diff[2], {Diff::Remove, 1, 0}));
} }
{
auto diff = find_diff("abcd", 4, "c", 1);
kak_assert(diff.size() == 3 and
eq(diff[0], {Diff::Remove, 2, 0}) and
eq(diff[1], {Diff::Keep, 1, 0}) and
eq(diff[2], {Diff::Remove, 1, 0}));
}
{
auto diff = find_diff("abcd", 4, "cdef", 4);
kak_assert(diff.size() == 3 and
eq(diff[0], {Diff::Remove, 2, 0}) and
eq(diff[1], {Diff::Keep, 2, 0}) and
eq(diff[2], {Diff::Add, 2, 2}));
}
}}; }};
UnitTest* UnitTest::list = nullptr; UnitTest* UnitTest::list = nullptr;