1 files changed, 106 insertions, 0 deletions
diff --git a/src/chunked.cc b/src/chunked.cc
new file mode 100644
index 0000000..99aea0d
--- /dev/null
+++ b/src/chunked.cc
@@ -0,0 +1,106 @@
+// -*- mode: c++; c-basic-offset: 2; -*-
+
+#include "common.hh"
+
+#include <cerrno>
+#include <cstdint>
+#include <cstdlib>
+
+#include "chunked.hh"
+
+namespace {
+
+enum State {
+  CHUNK,
+  IN_CHUNK,
+  TRAILER,
+  DONE,
+};
+
+class ChunkedImpl : public Chunked {
+public:
+  ChunkedImpl()
+    : state_(CHUNK), good_(true) {
+  }
+
+  size_t add(void const* data, size_t avail) override {
+    if (!good_) return 0;
+    auto const start = reinterpret_cast<char const*>(data);
+    auto const end = start + avail;
+    auto d = start;
+    while (true) {
+      if (d == end) return avail;
+      switch (state_) {
+      case CHUNK: {
+        auto p = find_crlf(d, end);
+        if (!p) return d - start;
+        char* x = nullptr;
+        errno = 0;
+        auto tmp = strtoull(d, &x, 16);
+        if (errno || (x != p && (!x || *x != ';'))) {
+          good_ = false;
+          return d - start;
+        }
+        size_ = tmp;
+        d = p + 2;
+        if (size_ == 0) {
+          // Last chunk
+          state_ = TRAILER;
+        } else {
+          state_ = IN_CHUNK;
+        }
+        break;
+      }
+      case IN_CHUNK:
+        if (static_cast<uint64_t>(end - d) < size_) {
+          return avail;
+        }
+        d += size_;
+        state_ = CHUNK;
+        break;
+      case TRAILER: {
+        auto p = find_crlf(d, end);
+        if (!p) return d - start;
+        if (p == d) {
+          state_ = DONE;
+        }
+        d = p + 2;
+        break;
+      }
+      case DONE:
+        return d - start;
+      }
+    }
+  }
+
+  bool good() const override {
+    return good_;
+  }
+
+  bool eof() const override {
+    return state_ == DONE;
+  }
+
+private:
+  char const* find_crlf(char const* start, char const* end) {
+    for (; start != end; ++start) {
+      if (*start == '\r') {
+        if (start + 1 == end) break;
+        if (start[1] == '\n') return start;
+      }
+    }
+    return nullptr;
+  }
+
+  State state_;
+  bool good_;
+  uint64_t size_;
+};
+
+}  // namespace
+
+// static
+Chunked* Chunked::create() {
+  return new ChunkedImpl();
+}
+