hexdump: code shrink

function                                             old     new   delta
remap                                                173     178      +5
move_mapping_lower                                   107     109      +2
move_mapping_further                                 141     143      +2
hexedit_main                                        1191    1176     -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/1 up/down: 9/-15)              Total: -6 bytes

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

diff --git a/miscutils/hexedit.c b/miscutils/hexedit.c
index eaf4ba57bef96aaaa90f4a79a74a9a45e7654fb3..bdb7683f28b1c29176628cf1ce9e86a23c2fdba7 100644 (file)
--- a/miscutils/hexedit.c
+++ b/miscutils/hexedit.c
@@ -159,7 +159,8 @@ static void redraw_cur_line(void)
        );
 }
 
-static void remap(unsigned cur_pos)
+/* if remappers return 0, no change was done */
+static int remap(unsigned cur_pos)
 {
        if (G.baseaddr)
                munmap(G.baseaddr, G_mapsize);
@@ -184,14 +185,15 @@ static void remap(unsigned cur_pos)
                /* we do have a mapped byte which is past eof */
                G.eof_byte = G.baseaddr + (G.size - G.offset);
        }
+       return 1;
 }
-static void move_mapping_further(void)
+static int move_mapping_further(void)
 {
        unsigned pos;
        unsigned pagesize;
 
        if ((G.size - G.offset) < G_mapsize)
-               return; /* can't move mapping even further, it's at the end already */
+               return 0; /* can't move mapping even further, it's at the end already */
 
        pagesize = getpagesize(); /* constant on most arches */
        pos = G.current_byte - G.baseaddr;
@@ -205,16 +207,17 @@ static void move_mapping_further(void)
                        }
                        pos -= pagesize;
                } while (pos >= pagesize);
-               remap(pos);
+               return remap(pos);
        }
+       return 0;
 }
-static void move_mapping_lower(void)
+static int move_mapping_lower(void)
 {
        unsigned pos;
        unsigned pagesize;
 
        if (G.offset == 0)
-               return; /* we are at 0 already */
+               return 0; /* we are at 0 already */
 
        pagesize = getpagesize(); /* constant on most arches */
        pos = G.current_byte - G.baseaddr;
@@ -229,7 +232,7 @@ static void move_mapping_lower(void)
        }
        pos -= pagesize;
 
-       remap(pos);
+       return remap(pos);
 }
 
 //usage:#define hexedit_trivial_usage
@@ -292,9 +295,8 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        if (G.current_byte == G.eof_byte) {
-                               move_mapping_further();
-                               if (G.current_byte == G.eof_byte) {
-                                       /* extend the file */
+                               if (!move_mapping_further()) {
+                                       /* already at EOF; extend the file */
                                        if (++G.size <= 0 /* overflow? */
                                         || ftruncate(G.fd, G.size) != 0 /* error extending? (e.g. block dev) */
                                        ) {
@@ -343,7 +345,7 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
                        if (G.current_byte >= G.eof_byte) {
                                move_mapping_further();
                                if (G.current_byte > G.eof_byte) {
-                                       /* eof - don't allow going past it */
+                                       /* _after_ eof - don't allow this */
                                        G.current_byte -= 16;
                                        break;
                                }
@@ -368,8 +370,7 @@ 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.baseaddr) {
-                                       move_mapping_lower();
-                                       if (G.current_byte == G.baseaddr)
+                                       if (!move_mapping_lower())
                                                break; /* first line, don't do anything */
                                }
                                G.half = 1;
@@ -386,9 +387,8 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
                case KEYCODE_UP:
  k_up:
                        if ((G.current_byte - G.baseaddr) < 16) {
-                               move_mapping_lower();
-                               if ((G.current_byte - G.baseaddr) < 16)
-                                       break;
+                               if (!move_mapping_lower())
+                                       break; /* already at 0, stop */
                        }
                        G.current_byte -= 16;
  up: