hexedit: implement "[enter] goto offset" key

This is a must if you need to edit sector 123456789999 on your /dev/disk.

   text	   data	    bss	    dec	    hex	filename
 922745	    481	   6832	 930058	  e310a	busybox_old
 923023	    481	   6832	 930336	  e3220	busybox_unstripped

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

2 files changed, 56 insertions, 27 deletions

diff --git a/miscutils/hexedit.c b/miscutils/hexedit.c
index b8627e826..eaf4ba57b 100644
--- a/miscutils/hexedit.c
+++ b/miscutils/hexedit.c
@@ -17,7 +17,8 @@
 
 #define ESC             "\033"
 #define HOME            ESC"[H"
-#define CLEAR           ESC"[H"ESC"[J"
+#define CLEAR           ESC"[J"
+#define CLEAR_TILL_EOL  ESC"[K"
 #define SET_ALT_SCR     ESC"[?1049h"
 #define POP_ALT_SCR     ESC"[?1049l"
 
@@ -30,7 +31,7 @@ struct globals {
         int fd;
         unsigned height;
         unsigned row;
-        uint8_t *addr;
+        uint8_t *baseaddr;
         uint8_t *current_byte;
         uint8_t *eof_byte;
         off_t size;
@@ -117,14 +118,15 @@ static void redraw(void)
 {
         uint8_t *data;
         off_t offset;
-        unsigned i;
+        unsigned i, pos;
 
-        data = G.addr;
-        offset = 0;
-        i = 0;
+        printf(HOME CLEAR);
+        data = G.baseaddr;
+        offset = G.offset;
+        pos = i = 0;
         while (i < G.height) {
                 char buf[LINEBUF_SIZE];
-                format_line(buf, data, offset);
+                pos = format_line(buf, data, offset);
                 printf(
                         "\r\n%s" + (!i)*2, /* print \r\n only on 2nd line and later */
                         buf
@@ -133,6 +135,7 @@ static void redraw(void)
                 offset += 16;
                 i++;
         }
+        printf(ESC"[1;%uH", pos + 1); /* position on 1st hex byte in first line */
 }
 
 static void redraw_cur_line(void)
@@ -144,7 +147,7 @@ static void redraw_cur_line(void)
 
         column = (0xf & (uintptr_t)G.current_byte);
         data = G.current_byte - column;
-        offset = G.offset + (data - G.addr);
+        offset = G.offset + (data - G.baseaddr);
 
         column = column*3 + G.half;
         column += format_line(buf, data, offset);
@@ -158,28 +161,28 @@ static void redraw_cur_line(void)
 
 static void remap(unsigned cur_pos)
 {
-        if (G.addr)
-                munmap(G.addr, G_mapsize);
+        if (G.baseaddr)
+                munmap(G.baseaddr, G_mapsize);
 
-        G.addr = mmap(NULL,
+        G.baseaddr = mmap(NULL,
                 G_mapsize,
                 PROT_READ | PROT_WRITE,
                 MAP_SHARED,
                 G.fd,
                 G.offset
         );
-        if (G.addr == MAP_FAILED) {
+        if (G.baseaddr == MAP_FAILED) {
                 restore_term();
                 bb_perror_msg_and_die("mmap");
         }
 
-        G.current_byte = G.addr + cur_pos;
+        G.current_byte = G.baseaddr + cur_pos;
 
-        G.eof_byte = G.addr + G_mapsize;
+        G.eof_byte = G.baseaddr + G_mapsize;
         if ((G.size - G.offset) < G_mapsize) {
                 /* mapping covers tail of the file */
                 /* we do have a mapped byte which is past eof */
-                G.eof_byte = G.addr + (G.size - G.offset);
+                G.eof_byte = G.baseaddr + (G.size - G.offset);
         }
 }
 static void move_mapping_further(void)
@@ -191,7 +194,7 @@ static void move_mapping_further(void)
                 return; /* can't move mapping even further, it's at the end already */
 
         pagesize = getpagesize(); /* constant on most arches */
-        pos = G.current_byte - G.addr;
+        pos = G.current_byte - G.baseaddr;
         if (pos >= pagesize) {
                 /* move offset up until current position is in 1st page */
                 do {
@@ -214,7 +217,7 @@ static void move_mapping_lower(void)
                 return; /* we are at 0 already */
 
         pagesize = getpagesize(); /* constant on most arches */
-        pos = G.current_byte - G.addr;
+        pos = G.current_byte - G.baseaddr;
 
         /* move offset down until current position is in last page */
         pos += pagesize;
@@ -252,18 +255,15 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
         G.size = xlseek(G.fd, 0, SEEK_END);
 
         /* TERMIOS_RAW_CRNL suppresses \n -> \r\n translation, helps with down-arrow */
+        printf(SET_ALT_SCR);
         set_termios_to_raw(STDIN_FILENO, &G.orig_termios, TERMIOS_RAW_CRNL);
         bb_signals(BB_FATAL_SIGS, sig_catcher);
 
         remap(0);
-
-        printf(SET_ALT_SCR);
         redraw();
-        printf(ESC"[1;10H"); /* position on 1st hex byte in first line */
 
 //TODO: //Home/End: start/end of line; '<'/'>': start/end of file
         //Backspace: undo
-        //Enter: goto specified position
         //Ctrl-L: redraw
         //Ctrl-Z: suspend
         //'/', Ctrl-S: search
@@ -367,9 +367,9 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
                         }
                         if ((0xf & (uintptr_t)G.current_byte) == 0) {
                                 /* leftmost pos, wrap to prev line */
-                                if (G.current_byte == G.addr) {
+                                if (G.current_byte == G.baseaddr) {
                                         move_mapping_lower();
-                                        if (G.current_byte == G.addr)
+                                        if (G.current_byte == G.baseaddr)
                                                 break; /* first line, don't do anything */
                                 }
                                 G.half = 1;
@@ -385,9 +385,9 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
                         cnt = G.height;
                 case KEYCODE_UP:
  k_up:
-                        if ((G.current_byte - G.addr) < 16) {
+                        if ((G.current_byte - G.baseaddr) < 16) {
                                 move_mapping_lower();
-                                if ((G.current_byte - G.addr) < 16)
+                                if ((G.current_byte - G.baseaddr) < 16)
                                         break;
                         }
                         G.current_byte -= 16;
@@ -403,6 +403,35 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
                         if (--cnt)
                                 goto k_up;
                         break;
+
+                case '\n':
+                case '\r':
+                        /* [Enter]: goto specified position */
+                        {
+                                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) {
+                                        off_t t;
+                                        unsigned pgmask;
+
+                                        t = bb_strtoull(buf, NULL, 0);
+                                        if (t >= G.size)
+                                                t = G.size - 1;
+                                        pgmask = getpagesize() - 1;
+                                        cnt = t & pgmask;
+                                        t = t & ~(off_t)pgmask;
+                                        if (t < 0)
+                                                cnt = t = 0;
+                                        G.offset = t;
+                                        remap(0);
+                                        redraw();
+                                        cnt /= 16;
+                                        if (cnt)
+                                                goto k_down;
+                                        break;
+                                }
+                                /* EOF/error on input: fall through to exiting */
+                        }
                 case CTRL('X'):
                         restore_term();
                         return EXIT_SUCCESS;
diff --git a/miscutils/less.c b/miscutils/less.c
index f869a9e82..d524b6c87 100644
--- a/miscutils/less.c
+++ b/miscutils/less.c
@@ -281,9 +281,9 @@ static void set_tty_cooked(void)
 
 /* Move the cursor to a position (x,y), where (0,0) is the
    top-left corner of the console */
-static void move_cursor(int line, int row)
+static void move_cursor(int line, int col)
 {
-        printf(ESC"[%u;%uH", line, row);
+        printf(ESC"[%u;%uH", line, col);
 }
 
 static void clear_line(void)