From 25c346e0d74d30aca49faa420c2d3858cc3ed9a6 Mon Sep 17 00:00:00 2001
From: d0k3 <tore.anon@gmail.com>
Date: Sun, 10 Apr 2016 15:55:39 +0200
Subject: [PATCH] Improved hex viewer navigation

---
 source/fs.c      | 16 ++++++++++++++++
 source/fs.h      |  3 +++
 source/godmode.c | 11 ++++++++---
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/source/fs.c b/source/fs.c
index d1ba651..8dbd4e6 100644
--- a/source/fs.c
+++ b/source/fs.c
@@ -188,6 +188,22 @@ size_t FileGetData(const char* path, u8* data, size_t size, size_t foffset)
     return 0;
 }
 
+size_t FileGetSize(const char* path) {
+    if (PathToNumFS(path) >= 0) {
+        FILINFO fno;
+        fno.lfname = NULL;
+        if (f_stat(path, &fno) != FR_OK)
+            return 0;
+        return fno.fsize;
+    } else if (GetVirtualSource(path)) {
+        VirtualFile vfile;
+        if (!FindVirtualFile(&vfile, path, 0))
+            return 0;
+        return vfile.size;
+    }
+    return 0;
+}
+
 bool PathCopyVirtual(const char* destdir, const char* orig) {
     char dest[256]; // maximum path name length in FAT
     char* oname = strrchr(orig, '/');
diff --git a/source/fs.h b/source/fs.h
index 639c163..7d3a2f4 100644
--- a/source/fs.h
+++ b/source/fs.h
@@ -44,6 +44,9 @@ bool FileCreateData(const char* path, u8* data, size_t size);
 /** Read data from file@offset **/
 size_t FileGetData(const char* path, u8* data, size_t size, size_t foffset);
 
+/** Get size of file **/
+size_t FileGetSize(const char* path);
+
 /** Recursively copy a file or directory **/
 bool PathCopy(const char* destdir, const char* orig);
 
diff --git a/source/godmode.c b/source/godmode.c
index daba6f7..e352d42 100644
--- a/source/godmode.c
+++ b/source/godmode.c
@@ -161,6 +161,7 @@ void DrawDirContents(DirStruct* contents, u32 cursor, u32* scroll) {
 u32 HexViewer(const char* path) {
     static u32 mode = 0;
     u8 data[(SCREEN_HEIGHT / 8) * 16]; // this is the maximum size
+    u32 fsize = FileGetSize(path);
     
     int x_off, x_hex, x_ascii;
     u32 vpad, hlpad, hrpad;
@@ -211,6 +212,9 @@ u32 HexViewer(const char* path) {
             last_mode = mode;
             ClearScreenF(true, false, COLOR_STD_BG);
         }
+        // fix offset (if required)
+        if (offset + total_shown > fsize + cols)
+            offset = (total_shown > fsize) ? 0 : (fsize + cols - total_shown - (fsize % cols));
         total_data = FileGetData(path, data, total_shown, offset); // get data
         
         // display data on screen
@@ -243,8 +247,8 @@ u32 HexViewer(const char* path) {
         
         // handle user input
         u32 pad_state = InputWait();
-        u32 step_ud = (pad_state & BUTTON_R1) ? total_shown * 16 : cols;
-        u32 step_lr = (pad_state & BUTTON_R1) ? total_shown * 256 : total_shown;
+        u32 step_ud = (pad_state & BUTTON_R1) ? (0x1000  - (0x1000  % cols))  : cols;
+        u32 step_lr = (pad_state & BUTTON_R1) ? (0x10000 - (0x10000 % cols)) : total_shown;
         if (pad_state & BUTTON_DOWN) offset += step_ud;
         else if (pad_state & BUTTON_RIGHT) offset += step_lr;
         else if (pad_state & BUTTON_UP) offset = (offset > step_ud) ? offset - step_ud : 0;
@@ -349,7 +353,8 @@ u32 GodMode() {
                 }
                 if (clipboard->n_entries && (strcspn(clipboard->entry[0].path, IMG_DRV) == 0))
                     clipboard->n_entries = 0; // remove invalid clipboard stuff
-            } else if (ShowPrompt(true, "Show HexViewer?\n \nControls:\n\x18\x19\x1A\x1B(+R) - Scroll\nR+Y - Switch view\nB - Exit\n")) {
+            } else if (FileGetSize(curr_entry->path) &&
+                ShowPrompt(true, "Show HexViewer?\n \nControls:\n\x18\x19\x1A\x1B(+R) - Scroll\nR+Y - Switch view\nB - Exit\n")) {
                 HexViewer(curr_entry->path);
             }
         } else if (*current_path && ((pad_state & BUTTON_B) || // one level down