add Codec/StbImage

CMakeLists.txt

@@ -139,6 +139,7 @@ target_sources(nf7
 
     file/audio_context.cc
     file/audio_device.cc
+    file/codec_stbimage.cc
     file/font_context.cc
     file/font_face.cc
     file/gl_obj.cc

file/codec_stbimage.cc

@@ -0,0 +1,94 @@
+#include <filesystem>
+#include <memory>
+#include <optional>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <stb_image.h>
+
+#include "nf7.hh"
+
+#include "common/generic_type_info.hh"
+#include "common/node.hh"
+#include "common/pure_node_file.hh"
+
+
+namespace nf7 {
+namespace {
+
+class StbImage final : public nf7::Node::Lambda,
+    public std::enable_shared_from_this<StbImage> {
+ public:
+  static inline nf7::GenericTypeInfo<nf7::PureNodeFile<StbImage>> kType = {
+    "Codec/StbImage", {"nf7::DirItem"},
+  };
+  static inline const nf7::Node::Meta kMeta = {{"input"}, {"image", "error"},};
+
+  using nf7::Node::Lambda::Lambda;
+  void Handle(const nf7::Node::Lambda::Msg& in) noexcept override
+  try {
+    std::string npath;
+    uint8_t comp = 4;
+    if (in.value.isTuple()) {
+      npath = in.value.tuple("npath").string();
+      comp  = in.value.
+          tupleOr("comp", static_cast<nf7::Value::Integer>(comp)).
+          integerOrScalar<uint8_t>();
+    } else {
+      npath = in.value.string();
+    }
+    env().ExecAsync(shared_from_this(), [=, this]() {
+      std::optional<nf7::Value> ret;
+      try {
+        ret = Exec(npath, comp);
+      } catch (nf7::Exception& e) {
+        log_->Error(e);
+      }
+      env().ExecSub(shared_from_this(), [this, in, ret]() {
+        if (ret) {
+          in.sender->Handle("image", *ret, shared_from_this());
+        } else {
+          in.sender->Handle("error", nf7::Value::Pulse {}, shared_from_this());
+        }
+      });
+    });
+  } catch (nf7::Exception& e) {
+    log_->Error(e);
+  }
+  nf7::Value Exec(const std::string& npath, uint8_t comp) {
+    if (comp <= 0 || 4 < comp) {
+      throw nf7::Exception {"invalid comp (0~4 are allwoed)"};
+    }
+
+    int w, h, actual_comp;
+    uint8_t* data = stbi_load(npath.c_str(), &w, &h, &actual_comp, comp);
+    if (!data) {
+      throw nf7::Exception {"failed to load image from "+npath};
+    }
+    if (comp != 0) {
+      actual_comp = comp;
+    }
+
+    const auto size =
+        static_cast<size_t>(w)*
+        static_cast<size_t>(h)*
+        static_cast<size_t>(actual_comp);
+    std::vector<uint8_t> buf(size);
+    std::memcpy(buf.data(), data, size);
+    stbi_image_free(data);
+    return std::vector<nf7::Value::TuplePair> {
+      {"buf",  std::move(buf)},
+      {"w",    static_cast<nf7::Value::Integer>(w)},
+      {"h",    static_cast<nf7::Value::Integer>(h)},
+      {"comp", static_cast<nf7::Value::Integer>(actual_comp)},
+    };
+;
+  }
+
+  std::shared_ptr<nf7::LoggerRef> log_;
+  static_assert(PureNodeFile_LoggerRef<StbImage>);
+};
+
+}
+}  // namespace nf7