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sinkToSource: avoid heap allocation

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This commit is contained in:
Philipp Otterbein 2025-01-23 00:18:55 +01:00 • committed by Jörg Thalheim
parent 06123f6284
commit 4f8f12f79a
1 changed files with 19 additions and 16 deletions
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35
src/libutil/serialise.cc
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@ -227,8 +227,7 @@ std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
throw EndOfFile("coroutine has finished");
}
size_t n = std::min(cur.size(), out_len);
memcpy(out, cur.data(), n);
size_t n = cur.copy(out, out_len);
cur.remove_prefix(n);
return n;
});
@ -260,7 +259,7 @@ std::unique_ptr<Source> sinkToSource(
{
struct SinkToSource : Source
{
typedef boost::coroutines2::coroutine<std::string> coro_t;
typedef boost::coroutines2::coroutine<std::string_view> coro_t;
std::function<void(Sink &)> fun;
std::function<void()> eof;
@ -271,33 +270,37 @@ std::unique_ptr<Source> sinkToSource(
{
}
std::string cur;
size_t pos = 0;
std::string_view cur;
size_t read(char * data, size_t len) override
{
if (!coro) {
bool hasCoro = coro.has_value();
if (!hasCoro) {
coro = coro_t::pull_type([&](coro_t::push_type & yield) {
LambdaSink sink([&](std::string_view data) {
if (!data.empty()) yield(std::string(data));
if (!data.empty()) {
yield(data);
}
});
fun(sink);
});
}
if (!*coro) { eof(); unreachable(); }
if (pos == cur.size()) {
if (!cur.empty()) {
if (cur.empty()) {
if (hasCoro) {
(*coro)();
}
cur = coro->get();
pos = 0;
if (*coro) {
cur = coro->get();
} else {
coro.reset();
eof();
unreachable();
}
}
auto n = std::min(cur.size() - pos, len);
memcpy(data, cur.data() + pos, n);
pos += n;
size_t n = cur.copy(data, len);
cur.remove_prefix(n);
return n;
}