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Hexdump: Allow identical lines to coalesce

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Coalesce feature is enabled by default when using
the program. Any number of lines identical to the preceding line
will be replaced by a single asterik.
This commit is contained in:
Pankaj Raghav 2021-11-19 11:17:40 +05:30 • committed by Ali Mohammad Pur
parent e08d213830
commit d72158045c
1 changed files with 30 additions and 2 deletions
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30
Userland/Utilities/hexdump.cpp
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@ -12,6 +12,12 @@
static constexpr size_t LINE_LENGTH_BYTES = 16; static constexpr size_t LINE_LENGTH_BYTES = 16;
enum class State {
Print,
PrintFiller,
SkipPrint
};
int main(int argc, char** argv) int main(int argc, char** argv)
{ {
Core::ArgsParser args_parser; Core::ArgsParser args_parser;
@ -59,20 +65,42 @@ int main(int argc, char** argv)
}; };
Array<u8, BUFSIZ> contents; Array<u8, BUFSIZ> contents;
Span<u8> previous_line;
static_assert(LINE_LENGTH_BYTES * 2 <= contents.size(), "Buffer is too small?!"); static_assert(LINE_LENGTH_BYTES * 2 <= contents.size(), "Buffer is too small?!");
size_t contents_size = 0; size_t contents_size = 0;
int nread; int nread;
auto state = State::Print;
while (true) { while (true) {
nread = file->read(&contents[contents_size], BUFSIZ - contents_size); nread = file->read(&contents[contents_size], BUFSIZ - contents_size);
if (nread <= 0) if (nread <= 0)
break; break;
contents_size += nread; contents_size += nread;
// Print as many complete lines as we can (possibly none).
size_t offset; size_t offset;
for (offset = 0; offset + LINE_LENGTH_BYTES - 1 < contents_size; offset += LINE_LENGTH_BYTES) { for (offset = 0; offset + LINE_LENGTH_BYTES - 1 < contents_size; offset += LINE_LENGTH_BYTES) {
auto current_line = contents.span().slice(offset, LINE_LENGTH_BYTES);
bool is_same_contents = (current_line == previous_line);
if (!is_same_contents)
state = State::Print;
else if (is_same_contents && (state != State::SkipPrint))
state = State::PrintFiller;
// Coalesce repeating lines
switch (state) {
case State::Print:
print_line(&contents[offset], LINE_LENGTH_BYTES); print_line(&contents[offset], LINE_LENGTH_BYTES);
break;
case State::PrintFiller:
outln("*");
state = State::SkipPrint;
break;
case State::SkipPrint:
break;
} }
previous_line = current_line;
}
contents_size -= offset; contents_size -= offset;
VERIFY(contents_size < LINE_LENGTH_BYTES); VERIFY(contents_size < LINE_LENGTH_BYTES);
// If we managed to make the buffer exactly full, &contents[BUFSIZ] would blow up. // If we managed to make the buffer exactly full, &contents[BUFSIZ] would blow up.