hexedit: fixes to "goto address" code

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 40 insertions, 20 deletions

diff --git a/miscutils/hexedit.c b/miscutils/hexedit.c
index 7e74e1f24..8334181c7 100644
--- a/miscutils/hexedit.c
+++ b/miscutils/hexedit.c
@@ -31,6 +31,7 @@ struct globals {
         int fd;
         unsigned height;
         unsigned row;
+        unsigned pagesize;
         uint8_t *baseaddr;
         uint8_t *current_byte;
         uint8_t *eof_byte;
@@ -45,8 +46,17 @@ struct globals {
         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
 } while (0)
 
-/* Hopefully there aren't arches with PAGE_SIZE > 64k */
-#define G_mapsize (64*1024)
+//TODO: move to libbb
+#if defined(__x86_64__) || defined(i386)
+# define G_pagesize 4096
+# define INIT_PAGESIZE() ((void)0)
+#else
+# define G_pagesize (G.pagesize)
+# define INIT_PAGESIZE() ((void)(G.pagesize = getpagesize()))
+#endif
+
+/* hopefully there aren't arches with PAGE_SIZE > 64k */
+#define G_mapsize  (64*1024)
 
 /* "12ef5670 (xx )*16 _1_3_5_7_9abcdef\n"NUL */
 #define LINEBUF_SIZE (8 + 1 + 3*16 + 16 + 1 + 1 /*paranoia:*/ + 13)
@@ -86,7 +96,7 @@ static int format_line(char *hex, uint8_t *data, off_t offset)
 #endif
         hex += ofs_pos;
 
-        text = hex + 16*3;
+        text = hex + 16 * 3;
         end1 = data + 15;
         if ((G.size - offset) > 0) {
                 end = end1;
@@ -114,28 +124,36 @@ static int format_line(char *hex, uint8_t *data, off_t offset)
         return ofs_pos;
 }
 
-static void redraw(void)
+static void redraw(unsigned cursor)
 {
         uint8_t *data;
         off_t offset;
         unsigned i, pos;
 
         printf(HOME CLEAR);
-        data = G.baseaddr;
-        offset = G.offset;
+
+        /* if cursor is past end of screen, how many lines to move down? */
+        i = (cursor / 16) - G.height + 1;
+        if ((int)i < 0)
+                i = 0;
+
+        data = G.baseaddr + i * 16;
+        offset = G.offset + i * 16;
+        cursor -= i * 16;
         pos = i = 0;
         while (i < G.height) {
                 char buf[LINEBUF_SIZE];
                 pos = format_line(buf, data, offset);
                 printf(
-                        "\r\n%s" + (!i)*2, /* print \r\n only on 2nd line and later */
+                        "\r\n%s" + (!i) * 2, /* print \r\n only on 2nd line and later */
                         buf
                 );
                 data += 16;
                 offset += 16;
                 i++;
         }
-        printf(ESC"[1;%uH", pos + 1); /* position on 1st hex byte in first line */
+
+        printf(ESC"[%u;%uH", 1 + cursor / 16, 1 + pos + (cursor & 0xf) * 3);
 }
 
 static void redraw_cur_line(void)
@@ -195,7 +213,7 @@ static int move_mapping_further(void)
         if ((G.size - G.offset) < G_mapsize)
                 return 0; /* can't move mapping even further, it's at the end already */
 
-        pagesize = getpagesize(); /* constant on most arches */
+        pagesize = G_pagesize; /* constant on most arches */
         pos = G.current_byte - G.baseaddr;
         if (pos >= pagesize) {
                 /* move offset up until current position is in 1st page */
@@ -219,7 +237,7 @@ static int move_mapping_lower(void)
         if (G.offset == 0)
                 return 0; /* we are at 0 already */
 
-        pagesize = getpagesize(); /* constant on most arches */
+        pagesize = G_pagesize; /* constant on most arches */
         pos = G.current_byte - G.baseaddr;
 
         /* move offset down until current position is in last page */
@@ -243,6 +261,7 @@ int hexedit_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int hexedit_main(int argc UNUSED_PARAM, char **argv)
 {
         INIT_G();
+        INIT_PAGESIZE();
 
         get_terminal_width_height(-1, NULL, &G.height);
         if (1) {
@@ -263,7 +282,7 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
         bb_signals(BB_FATAL_SIGS, sig_catcher);
 
         remap(0);
-        redraw();
+        redraw(0);
 
 //TODO: //Home/End: start/end of line; '<'/'>': start/end of file
         //Backspace: undo
@@ -411,26 +430,27 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
                         {
                                 char buf[sizeof(G.offset)*3 + 4];
                                 printf(ESC"[999;1H" CLEAR_TILL_EOL); /* go to last line */
-                                if (read_line_input(NULL, "Go to (dec,0Xhex,0oct): ", buf, sizeof(buf)) >= 0) {
+                                if (read_line_input(NULL, "Go to (dec,0Xhex,0oct): ", buf, sizeof(buf)) > 0) {
                                         off_t t;
                                         unsigned pgmask;
 
                                         t = bb_strtoull(buf, NULL, 0);
                                         if (t >= G.size)
                                                 t = G.size - 1;
-                                        pgmask = getpagesize() - 1;
+                                        pgmask = G_pagesize - 1;
                                         cnt = t & pgmask;
                                         t = t & ~(off_t)pgmask;
                                         if (t < 0)
                                                 cnt = t = 0;
+                                        if (t != 0 && cnt < 0x1ff) {
+                                                /* very close to end of page, possibly to EOF */
+                                                /* move one page lower */
+                                                t -= G_pagesize;
+                                                cnt += G_pagesize;
+                                        }
                                         G.offset = t;
-                                        remap(cnt & 0xf);
-                                        redraw();
-                                        if (cnt & 0xf)
-                                                printf(ESC"[%uC", (cnt & 0xf) * 3); /* cursor right 3*i */
-                                        cnt >>= 4;
-                                        if (cnt)
-                                                goto k_down;
+                                        remap(cnt);
+                                        redraw(cnt);
                                         break;
                                 }
                                 /* EOF/error on input: fall through to exiting */