From 8dba4647e9729cdea27f6b0165e82f20ee1d7266 Mon Sep 17 00:00:00 2001
From: Derek Buitenhuis <derek.buitenhuis@gmail.com>
Date: Sun, 6 Jan 2019 12:44:11 -0500
Subject: [PATCH] Implement PGUP and PGDOWN support for skipping full screens

Implements part of #2.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
---
 LICENSE   |  2 +-
 README.md |  5 +++--
 main.c    | 38 +++++++++++++++++++++++++++++++++++++-
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/LICENSE b/LICENSE
index 22c6e5e..9394f6a 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 ISC License (ISC)
 
-Copyright (c) 2016, Derek Buitenhuis <derek.buitenhuis at gmail dot com>
+Copyright (c) 2016-2019, Derek Buitenhuis <derek.buitenhuis at gmail dot com>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted, provided that the above
diff --git a/README.md b/README.md
index ab6d677..f2a37ee 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 BXD: Binary Hex Diff
 ====================
 
-Copyright (c) 2016 Derek Buitenhuis <derek.buitenhuis at gmail dot com>
+Copyright (c) 2016-2019 Derek Buitenhuis <derek.buitenhuis at gmail dot com>
 
 ![BXD](http://chromashift.org/bxd.png)
 
@@ -28,7 +28,7 @@ Usage
 Currently, the command like arguments are very simple:
 
     Binary Hex Diff
-    Copyright (c) 2016 Derek Buitenhuis.
+    Copyright (c) 2016-2019 Derek Buitenhuis.
 
     A tool to compare two arbitrarily sized binary files.
 
@@ -39,6 +39,7 @@ Keys are:
 * `q` to quit.
 * `space` to seek to next diff.
 * `up`/`down` to scroll up and down.
+* `pgup` / `pgdn` to scroll up and down by one full screen.
 
 Current Limitations
 -------------------
diff --git a/main.c b/main.c
index b0d47ea..15ec274 100644
--- a/main.c
+++ b/main.c
@@ -25,7 +25,7 @@ int main(int argc, char *argv[])
 
     if (argc < 3) {
         fprintf(stderr, "Binary Hex Diff\n"
-                        "Copyright (c) 2016 Derek Buitenhuis.\n\n"
+                        "Copyright (c) 2016-2019 Derek Buitenhuis.\n\n"
                         "A tool to compare two arbitrarily sized binary files.\n\n"
                         "Usage: %s file1 file2\n\n", argv[0]);
         return 0;
@@ -124,6 +124,42 @@ int main(int argc, char *argv[])
 
                     break;
                 }
+                case TB_KEY_PGUP: {
+                    unsigned int lpu = get_line_per_side();
+
+                    for (unsigned int i = 0; i < lpu; i++) {
+                        if (ctx.offset == 0) {
+                            if (ctx.nf_offset != 0 && ctx.of_offset != 0)
+                                load_previous(&ctx, &lbuf[0], scratch);
+                        } else {
+                            ctx.offset -= 2;
+                        }
+                    }
+                    break;
+                }
+                case TB_KEY_PGDN: {
+                    unsigned int cpl = get_char_per_line();
+                    unsigned int lpu = get_line_per_side();
+
+                    if (ctx.done)
+                        continue;
+
+                    for (unsigned int i = 0; i < lpu && !ctx.done; i++) {
+                        ctx.offset += 2;
+
+                        if (((size_t) ctx.offset / 2) * cpl + cpl * lpu >= ctx.blocksize) {
+                            bool err;
+
+                            calc_next_mask(&ctx, &lbuf[0], scratch, &err);
+
+                            if (err)
+                                goto end;
+                        }
+
+                        draw_ui_dummy(&ctx);
+                    }
+                    break;
+                }
                 case TB_KEY_SPACE: {
                     unsigned int cpl = get_char_per_line();
                     unsigned int lpu = get_line_per_side();