add jpegdec/caps:dc (#369)

nx/include/switch.h

@@ -93,6 +93,7 @@ extern "C" {
 #include "switch/services/psc.h"
 #include "switch/services/caps.h"
 #include "switch/services/capsa.h"
+#include "switch/services/capsdc.h"
 #include "switch/services/capsu.h"
 #include "switch/services/capssc.h"
 #include "switch/services/capssu.h"

nx/include/switch/services/caps.h

@@ -65,7 +65,10 @@ typedef struct {
 
 /// ScreenShotDecodeOption
 typedef struct {
-    u8 unk_x0[0x20];                            ///< Unknown. Set to all-zero by official sw.
+    u8 fancy_upsampling;    ///< See libjpeg-turbo do_fancy_upsampling.
+    u8 block_smoothing;     ///< See libjpeg-turbo do_block_smoothing.
+    u8 pad_x2[0x6];         ///< Padding.
+    u64 unk_x8[0x3];        ///< Unknown. Ignored by official sw.
 } CapsScreenShotDecodeOption;
 
 /// AlbumFileDateTime. This corresponds to each field in the Album entry filename, prior to the "-": "YYYYMMDDHHMMSSII".

nx/include/switch/services/capsdc.h

@@ -0,0 +1,32 @@
+/**
+ * @file capsdc.h
+ * @brief Jpeg Decoder (caps:dc) service IPC wrapper. Only available on [4.0.0+].
+ * @note Only holds one session that is occupied by capsrv.
+ * @author Behemoth
+ * @copyright libnx Authors
+ */
+#pragma once
+#include "../types.h"
+#include "../sf/service.h"
+#include "../services/caps.h"
+
+/// Initialize caps:dc
+Result capsdcInitialize(void);
+
+/// Exit caps:dc.
+void capsdcExit(void);
+
+/// Gets the Service for caps:dc.
+Service* capsdcGetServiceSession(void);
+
+/**
+ * @brief Decodes a jpeg buffer into RGBX.
+ * @param[in] width Image width.
+ * @param[in] height Image height.
+ * @param[in] opts \ref CapsScreenShotDecodeOption.
+ * @param[in] jpeg Jpeg image input buffer.
+ * @param[in] jpeg_size Input image buffer size.
+ * @param[out] out_image RGBA8 image output buffer.
+ * @param[in] out_image_size Output image buffer size, should be at least large enough for RGBA8 width x height.
+ */
+Result capsdcDecodeJpeg(u32 width, u32 height, const CapsScreenShotDecodeOption *opts, const void* jpeg, size_t jpeg_size, void* out_image, size_t out_image_size);

nx/source/services/capsdc.c

@@ -0,0 +1,41 @@
+#define NX_SERVICE_ASSUME_NON_DOMAIN
+#include "service_guard.h"
+#include "runtime/hosversion.h"
+#include "services/capsdc.h"
+
+static Service g_capsdcSrv;
+
+NX_GENERATE_SERVICE_GUARD(capsdc);
+
+Result _capsdcInitialize(void) {
+    if (hosversionBefore(4,0,0))
+        return MAKERESULT(Module_Libnx, LibnxError_IncompatSysVer);
+
+    return smGetService(&g_capsdcSrv, "caps:dc");
+}
+
+void _capsdcCleanup(void) {
+    serviceClose(&g_capsdcSrv);
+}
+
+Service* capsdcGetServiceSession(void) {
+    return &g_capsdcSrv;
+}
+
+Result capsdcDecodeJpeg(u32 width, u32 height, const CapsScreenShotDecodeOption *opts, const void* jpeg, size_t jpeg_size, void* out_image, size_t out_image_size) {
+    const struct {
+        u32 width;
+        u32 height;
+        CapsScreenShotDecodeOption opts;
+    } in = { width, height, *opts };
+    return serviceDispatchIn(&g_capsdcSrv, 3001, in,
+        .buffer_attrs = {
+            SfBufferAttr_In | SfBufferAttr_HipcMapAlias,
+            SfBufferAttr_Out | SfBufferAttr_HipcMapAlias | SfBufferAttr_HipcMapTransferAllowsNonSecure,
+        },
+        .buffers = {
+            { jpeg, jpeg_size },
+            { out_image, out_image_size },
+        }
+    );
+}