init version

.formatter.exs

@@ -0,0 +1,5 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"],
+  line_length: 80
+]

.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+jaypeg-*.tar
+
+# Build artifacts
+priv/jaypeg.so
+priv/jaypeg.so.*

Makefile

@@ -0,0 +1,15 @@
+CFLAGS = -g -O3 -Wall -std=c99
+ERLANG_PATH = $(shell erl -eval 'io:format("~s", [lists:concat([code:root_dir(), "/erts-", erlang:system_info(version), "/include"])])' -s init stop -noshell)
+CFLAGS += -I$(ERLANG_PATH)
+CFLAGS += -Ic_src
+CFLAGS += -g -DDEBUG -D_GNU_SOURCE
+ifeq ($(shell uname -s), Darwin)
+LDFLAGS += -flat_namespace -undefined suppress
+endif
+LIB_SO_NAME = priv/jaypeg.so
+CFLAGS += -fPIC
+NIF=c_src/jaypeg.c
+
+$(LIB_SO_NAME): $(NIF)
+	mkdir -p priv
+	$(CC) $(CFLAGS) -shared $(LDFLAGS) $^ -ljpeg -o $@

README.md

@@ -0,0 +1,21 @@
+# Jaypeg
+
+**TODO: Add description**
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed
+by adding `jaypeg` to your list of dependencies in `mix.exs`:
+
+```elixir
+def deps do
+  [
+    {:jaypeg, "~> 0.1.0"}
+  ]
+end
+```
+
+Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
+and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
+be found at [https://hexdocs.pm/jaypeg](https://hexdocs.pm/jaypeg).
+

c_src/jaypeg.c

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+#include "erl_nif.h"
+
+#define STB_IMAGE_RESIZE_IMPLEMENTATION
+#include "stb_image_resize.h"
+
+#include <jpeglib.h>
+
+ERL_NIF_TERM decode_properties(ErlNifEnv *env, int width, int height,
+                               int channels) {
+  ERL_NIF_TERM width_term;
+  width_term = enif_make_tuple2(env, enif_make_atom(env, "width"),
+                                enif_make_int(env, width));
+
+  ERL_NIF_TERM height_term;
+  height_term = enif_make_tuple2(env, enif_make_atom(env, "height"),
+                                 enif_make_int(env, height));
+
+  ERL_NIF_TERM channels_term;
+  channels_term = enif_make_tuple2(env, enif_make_atom(env, "channels"),
+                                   enif_make_int(env, channels));
+
+  ERL_NIF_TERM items[3] = {width_term, height_term, channels_term};
+  return enif_make_list_from_array(
+    env, items, sizeof(items) / sizeof(ERL_NIF_TERM));
+}
+
+static ERL_NIF_TERM decode(ErlNifEnv *env, int argc,
+                           const ERL_NIF_TERM argv[]) {
+  ERL_NIF_TERM jpeg_binary_term;
+  jpeg_binary_term = argv[0];
+  if (!enif_is_binary(env, jpeg_binary_term)) {
+    return enif_make_badarg(env);
+  }
+
+  ErlNifBinary jpeg_binary;
+  enif_inspect_binary(env, jpeg_binary_term, &jpeg_binary);
+
+  struct jpeg_decompress_struct cinfo;
+  struct jpeg_error_mgr jerr;
+  cinfo.err = jpeg_std_error(&jerr);
+  jpeg_create_decompress(&cinfo);
+
+  FILE * img_src = fmemopen(jpeg_binary.data, jpeg_binary.size, "rb");
+  if (img_src == NULL)
+    return enif_make_tuple2(env, enif_make_atom(env, "error"),
+                            enif_make_atom(env, "fmemopen"));
+
+  jpeg_stdio_src(&cinfo, img_src);
+
+  int error_check;
+  error_check = jpeg_read_header(&cinfo, TRUE);
+  if (error_check != 1)
+    return enif_make_tuple2(env, enif_make_atom(env, "error"),
+                            enif_make_atom(env, "bad_jpeg"));
+
+  jpeg_start_decompress(&cinfo);
+
+  int width, height, num_pixels, row_stride;
+  width = cinfo.output_width;
+  height = cinfo.output_height;
+  num_pixels = cinfo.output_components;
+  unsigned long output_size;
+  output_size = width * height * num_pixels;
+  row_stride = width * num_pixels;
+
+  ErlNifBinary bmp_binary;
+  enif_alloc_binary(output_size, &bmp_binary);
+
+  while (cinfo.output_scanline < cinfo.output_height) {
+    unsigned char *buf[1];
+    buf[0] = bmp_binary.data + cinfo.output_scanline * row_stride;
+    jpeg_read_scanlines(&cinfo, buf, 1);
+  }
+
+  jpeg_finish_decompress(&cinfo);
+  jpeg_destroy_decompress(&cinfo);
+
+  fclose(img_src);
+
+  ERL_NIF_TERM bmp_term;
+  bmp_term = enif_make_binary(env, &bmp_binary);
+  ERL_NIF_TERM properties_term;
+  properties_term = decode_properties(env, width, height, num_pixels);
+
+  return enif_make_tuple3(
+    env, enif_make_atom(env, "ok"), bmp_term, properties_term);
+}
+
+static ERL_NIF_TERM resize(ErlNifEnv *env, int argc,
+                           const ERL_NIF_TERM argv[]) {
+  ErlNifBinary in_img_binary;
+  enif_inspect_binary(env, argv[0], &in_img_binary);
+
+  unsigned in_width, in_height, num_channels;
+  enif_get_uint(env, argv[1], &in_width);
+  enif_get_uint(env, argv[2], &in_height);
+  enif_get_uint(env, argv[3], &num_channels);
+
+  unsigned out_width, out_height;
+  enif_get_uint(env, argv[4], &out_width);
+  enif_get_uint(env, argv[5], &out_height);
+
+  unsigned long output_size;
+  output_size = out_width * out_height * num_channels;
+  ErlNifBinary out_img_binary;
+  enif_alloc_binary(output_size, &out_img_binary);
+
+  if (stbir_resize_uint8(
+        in_img_binary.data, in_width, in_height, 0,
+        out_img_binary.data, out_width, out_height, 0, num_channels) != 1)
+    return enif_make_tuple2(
+      env,
+      enif_make_atom(env, "error"),
+      enif_make_atom(env, "resize"));
+
+  ERL_NIF_TERM out_img_term;
+  out_img_term = enif_make_binary(env, &out_img_binary);
+
+  return enif_make_tuple2(env, enif_make_atom(env, "ok"), out_img_term);
+}
+
+static ErlNifFunc nif_funcs[] = {
+  {"decode", 1, decode},
+  {"resize", 6, resize}
+};
+
+ERL_NIF_INIT(Elixir.Jaypeg, nif_funcs, NULL, NULL, NULL, NULL)
+
+/* Local Variables: */
+/* c-basic-offset: 2 */
+/* End: */