conspy: code shrink

function                                             old     new   delta
screen_read_close                                    114     187     +73
set_cursor                                             -      53     +53
cleanup                                               93      91      -2
screen_dump                                          202     197      -5
curon                                                 34       -     -34
screen_char                                          351     308     -43
conspy_main                                         1444    1264    -180
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 1/4 up/down: 126/-264)         Total: -138 bytes

Signed-off-by: Pascal Bellard <pascal.bellard@ads-lu.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 101 insertions, 110 deletions

diff --git a/miscutils/conspy.c b/miscutils/conspy.c
index 6f2f0255c..565922ca0 100644
--- a/miscutils/conspy.c
+++ b/miscutils/conspy.c
@@ -46,9 +46,9 @@ struct screen_info {
         unsigned char lines, cols, cursor_x, cursor_y;
 };
 
-#define CHAR(x) ((uint8_t)((x)[0]))
-#define ATTR(x) ((uint8_t)((x)[1]))
-#define NEXT(x) ((x)+=2)
+#define CHAR(x) (*(uint8_t*)(x))
+#define ATTR(x) (((uint8_t*)(x))[1])
+#define NEXT(x) ((x) += 2)
 #define DATA(x) (*(uint16_t*)(x))
 
 struct globals {
@@ -56,25 +56,25 @@ struct globals {
         int size;
         int x, y;
         int kbd_fd;
-        int vcsa_fd;
         int ioerror_count;
         int key_count;
         int escape_count;
         int nokeys;
         int current;
+        int first_line_offset;
+        int last_attr;
         // cached local tty parameters
         unsigned width;
         unsigned height;
         unsigned col;
         unsigned line;
-        smallint curoff;
-        uint8_t last_attr;
-        uint8_t force_attr_change;
+        smallint curoff; // unknown:0 cursor on:-1 cursor off:1
         char attrbuf[sizeof("\033[0;1;5;30;40m")];
         // remote console
         struct screen_info remote;
         // saved local tty terminfo
         struct termios term_orig;
+        char vcsa_name[sizeof("/dev/vcsaNN")];
 };
 
 #define G (*ptr_to_globals)
@@ -82,7 +82,8 @@ struct globals {
         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
         G.attrbuf[0] = '\033'; \
         G.attrbuf[1] = '['; \
-        G.force_attr_change = 0xff; \
+        G.width = G.height = UINT_MAX; \
+        G.last_attr--; \
 } while (0)
 
 enum {
@@ -96,24 +97,80 @@ enum {
 #define FLAG(x) (1 << FLAG_##x)
 #define BW (option_mask32 & FLAG(n))
 
+static void clrscr(void)
+{
+        // Home, clear till end of screen
+        fputs("\033[1;1H" "\033[J", stdout);
+        G.col = G.line = 0;
+}
+
+static void set_cursor(int state)
+{
+        if (G.curoff != state) {
+                G.curoff = state;
+                fputs("\033[?25", stdout);
+                bb_putchar("h?l"[1 + state]);
+        }
+}
+
+static void gotoxy(int col, int line)
+{
+        if (G.col != col || G.line != line) {
+                G.col = col;
+                G.line = line;
+                printf("\033[%u;%uH", line + 1, col + 1);
+        }
+}
+
+static void cleanup(int code)
+{
+        set_cursor(-1); // cursor on
+        tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig);
+        if (ENABLE_FEATURE_CLEAN_UP) {
+                close(G.kbd_fd);
+        }
+        // Reset attributes
+        if (!BW)
+                fputs("\033[0m", stdout);
+        bb_putchar('\n');
+        if (code > 1)
+                kill_myself_with_sig(code);
+        exit(code);
+}
+
 static void screen_read_close(void)
 {
         unsigned i, j;
-        char *data = G.data + G.current;
-
-        xread(G.vcsa_fd, data, G.size);
+        int vcsa_fd;
+        char *data;
+
+        // Close & re-open vcsa in case they have swapped virtual consoles
+        vcsa_fd = xopen(G.vcsa_name, O_RDONLY);
+        xread(vcsa_fd, &G.remote, 4);
+        i = G.remote.cols * 2;
+        G.first_line_offset = G.y * i;
+        i *= G.remote.lines;
+        if (G.data == NULL) {
+                G.size = i;
+                G.data = xzalloc(2 * i);
+        }
+        else if (G.size != i) {
+                cleanup(1);
+        }
+        data = G.data + G.current;
+        xread(vcsa_fd, data, G.size);
+        close(vcsa_fd);
         for (i = 0; i < G.remote.lines; i++) {
                 for (j = 0; j < G.remote.cols; j++, NEXT(data)) {
                         unsigned x = j - G.x; // if will catch j < G.x too
                         unsigned y = i - G.y; // if will catch i < G.y too
 
                         if (CHAR(data) < ' ')
-                                *data = ' '; // CHAR(data) = ' ';
+                                CHAR(data) = ' ';
                         if (y >= G.height || x >= G.width)
                                 DATA(data) = 0;
                 }
         }
-        close(G.vcsa_fd);
 }
 
 static void screen_char(char *data)
@@ -121,7 +178,7 @@ static void screen_char(char *data)
         if (!BW) {
                 uint8_t attr = ATTR(data);
                 //uint8_t attr = ATTR(data) >> 1; // for framebuffer console
-                uint8_t attr_diff = (G.last_attr ^ attr) | G.force_attr_change;
+                uint8_t attr_diff = G.last_attr ^ attr;
 
                 if (attr_diff) {
 // Attribute layout for VGA compatible text videobuffer:
@@ -153,19 +210,20 @@ static void screen_char(char *data)
                         const uint8_t bg_mask = 0x70, blink_mask = 0x80;
                         char *ptr;
 
-                        ptr = G.attrbuf + 2; /* skip "ESC [" */
+                        ptr = G.attrbuf + 2; // skip "ESC ["
 
                         // (G.last_attr & ~attr) has 1 only where
                         // G.last_attr has 1 but attr has 0.
                         // Here we check whether we have transition
                         // bold->non-bold or blink->non-blink:
-                        if ((G.last_attr & ~attr) & (bold_mask | blink_mask)) {
+                        if (G.last_attr < 0  // initial value
+                         || ((G.last_attr & ~attr) & (bold_mask | blink_mask)) != 0
+                        ) {
                                 *ptr++ = '0'; // "reset all attrs"
                                 *ptr++ = ';';
                                 // must set fg & bg, maybe need to set bold or blink:
                                 attr_diff = attr | ~(bold_mask | blink_mask);
                         }
-                        G.force_attr_change = 0;
                         G.last_attr = attr;
                         if (attr_diff & bold_mask) {
                                 *ptr++ = '1';
@@ -196,44 +254,12 @@ static void screen_char(char *data)
         G.col++;
 }
 
-static void clrscr(void)
-{
-        // Home, clear till end of src, cursor on
-        fputs("\033[1;1H" "\033[J" "\033[?25h", stdout);
-        G.curoff = G.col = G.line = 0;
-}
-
-static void curoff(void)
-{
-        if (!G.curoff) {
-                G.curoff = 1;
-                fputs("\033[?25l", stdout);
-        }
-}
-
-static void curon(void)
-{
-        if (G.curoff) {
-                G.curoff = 0;
-                fputs("\033[?25h", stdout);
-        }
-}
-
-static void gotoxy(int col, int line)
-{
-        if (G.col != col || G.line != line) {
-                G.col = col;
-                G.line = line;
-                printf("\033[%u;%uH", line + 1, col + 1);
-        }
-}
-
 static void screen_dump(void)
 {
         int linefeed_cnt;
         int line, col;
         int linecnt = G.remote.lines - G.y;
-        char *data = G.data + G.current + (2 * G.y * G.remote.cols);
+        char *data = G.data + G.current + G.first_line_offset;
 
         linefeed_cnt = 0;
         for (line = 0; line < linecnt && line < G.height; line++) {
@@ -263,41 +289,13 @@ static void curmove(void)
 {
         unsigned cx = G.remote.cursor_x - G.x;
         unsigned cy = G.remote.cursor_y - G.y;
+        int cursor = 1;
 
-        if (cx >= G.width || cy >= G.height) {
-                curoff();
-        } else {
-                curon();
+        if (cx < G.width && cy < G.height) {
                 gotoxy(cx, cy);
+                cursor = -1;
         }
-        fflush_all();
-}
-
-static void cleanup(int code)
-{
-        curon();
-        fflush_all();
-        tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig);
-        if (ENABLE_FEATURE_CLEAN_UP) {
-                close(G.kbd_fd);
-        }
-        // Reset attributes
-        if (!BW)
-                fputs("\033[0m", stdout);
-        bb_putchar('\n');
-        if (code > 1)
-                kill_myself_with_sig(code); // does not return
-        exit(code);
-}
-
-static void get_initial_data(const char* vcsa_name)
-{
-        G.vcsa_fd = xopen(vcsa_name, O_RDONLY);
-        xread(G.vcsa_fd, &G.remote, 4);
-        G.size = G.remote.cols * G.remote.lines * 2;
-        G.width = G.height = UINT_MAX;
-        G.data = xzalloc(2 * G.size);
-        screen_read_close();
+        set_cursor(cursor);
 }
 
 static void create_cdev_if_doesnt_exist(const char* name, dev_t dev)
@@ -345,7 +343,6 @@ static NOINLINE void start_shell_in_child(const char* tty_name)
 int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int conspy_main(int argc UNUSED_PARAM, char **argv)
 {
-        char vcsa_name[sizeof("/dev/vcsaNN")];
         char tty_name[sizeof("/dev/ttyNN")];
 #define keybuf bb_common_bufsiz1
         struct termios termbuf;
@@ -365,7 +362,7 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
         applet_long_options = getopt_longopts;
 #endif
         INIT_G();
-        strcpy(vcsa_name, "/dev/vcsa");
+        strcpy(G.vcsa_name, "/dev/vcsa");
 
         opt_complementary = "x+:y+"; // numeric params
         opts = getopt32(argv, "vcsndfx:y:", &G.x, &G.y);
@@ -373,19 +370,19 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
         ttynum = 0;
         if (argv[0]) {
                 ttynum = xatou_range(argv[0], 0, 63);
-                sprintf(vcsa_name + sizeof("/dev/vcsa")-1, "%u", ttynum);
+                sprintf(G.vcsa_name + sizeof("/dev/vcsa")-1, "%u", ttynum);
         }
         sprintf(tty_name, "%s%u", "/dev/tty", ttynum);
         if (opts & FLAG(c)) {
                 if ((opts & (FLAG(s)|FLAG(v))) != FLAG(v))
                         create_cdev_if_doesnt_exist(tty_name, makedev(4, ttynum));
-                create_cdev_if_doesnt_exist(vcsa_name, makedev(7, 128 + ttynum));
+                create_cdev_if_doesnt_exist(G.vcsa_name, makedev(7, 128 + ttynum));
         }
         if ((opts & FLAG(s)) && ttynum) {
                 start_shell_in_child(tty_name);
         }
 
-        get_initial_data(vcsa_name);
+        screen_read_close();
         if (opts & FLAG(d)) {
                 screen_dump();
                 bb_putchar('\n');
@@ -412,17 +409,11 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                 int i, j;
                 char *data, *old;
 
-                // Close & re-open vcsa in case they have
-                // swapped virtual consoles
-                G.vcsa_fd = xopen(vcsa_name, O_RDONLY);
-                xread(G.vcsa_fd, &G.remote, 4);
-                if (G.size != (G.remote.cols * G.remote.lines * 2)) {
-                        cleanup(1);
-                }
+                // in the first loop G.width = G.height = 0: refresh
                 i = G.width;
                 j = G.height;
                 get_terminal_width_height(G.kbd_fd, &G.width, &G.height);
-                if ((option_mask32 & FLAG(f))) {
+                if (option_mask32 & FLAG(f)) {
                         int nx = G.remote.cursor_x - G.width + 1;
                         int ny = G.remote.cursor_y - G.height + 1;
 
@@ -454,8 +445,8 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                         screen_dump();
                 } else {
                         // For each remote line
-                        old += G.y * G.remote.cols * 2;
-                        data += G.y * G.remote.cols * 2;
+                        old += G.first_line_offset;
+                        data += G.first_line_offset;
                         for (i = G.y; i < G.remote.lines; i++) {
                                 char *first = NULL; // first char which needs updating
                                 char *last = last;  // last char which needs updating
@@ -463,10 +454,8 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
 
                                 if (iy >= G.height)
                                         break;
-                                old += G.x * 2;
-                                data += G.x * 2;
-                                for (j = G.x; j < G.remote.cols; j++, NEXT(old), NEXT(data)) {
-                                        unsigned jx = j - G.x;
+                                for (j = 0; j < G.remote.cols; j++, NEXT(old), NEXT(data)) {
+                                        unsigned jx = j - G.x; // if will catch j >= G.x too
 
                                         if (jx < G.width && DATA(data) != DATA(old)) {
                                                 last = data;
@@ -486,6 +475,7 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                 curmove();
 
                 // Wait for local user keypresses
+                fflush_all();
                 pfd.fd = G.kbd_fd;
                 pfd.events = POLLIN;
                 bytes_read = 0;
@@ -532,15 +522,16 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                         else if (kbd_mode != K_XLATE && kbd_mode != K_UNICODE)
                                 G.key_count = 0; // scan code mode
                         else {
-                                for (i = 0; i < G.key_count && result != -1; i++)
-                                        result = ioctl(handle, TIOCSTI, keybuf + i);
-                                G.key_count -= i;
+                                char *p = keybuf;
+                                for (; G.key_count != 0 && result != -1; p++, G.key_count--) {
+                                        result = ioctl(handle, TIOCSTI, p);
+                                        // If there is an application on console which reacts
+                                        // to keypresses, we need to make our first sleep
+                                        // shorter to quickly redraw whatever it printed there.
+                                        poll_timeout_ms = 20;
+                                }
                                 if (G.key_count)
-                                        memmove(keybuf, keybuf + i, G.key_count);
-                                // If there is an application on console which reacts
-                                // to keypresses, we need to make our first sleep
-                                // shorter to quickly redraw whatever it printed there.
-                                poll_timeout_ms = 20;
+                                        memmove(keybuf, p, G.key_count);
                         }
                         // Close & re-open tty in case they have
                         // swapped virtual consoles
@@ -553,5 +544,5 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                         else if (errno != EIO || ++G.ioerror_count > 4)
                                 cleanup(1);
                 }
-        }
+        } /* while (1) */
 }