Initial/preliminary refactor for thresholds

Makefile

@@ -7,7 +7,7 @@ ZSHDIR ?= $(DESTDIR)$(PREFIX)/share/zsh
 BSHDIR ?= $(DESTDIR)$(PREFIX)/share/bash-completions
 
 CC = clang
-CFLAGS ?= -g -O2 -fPIE -pie -flto -D_FORTIFY_SOURCE=2 -fstack-protector-strong --param=ssp-buffer-size=1 -Weverything -Werror -std=c11 -fsanitize=undefined -fsanitize-trap=undefined -Wl,-z,relro,-z,now
+CFLAGS ?= -g -ggdb -O2 -fPIE -pie -flto -D_FORTIFY_SOURCE=2 -fstack-protector-strong --param=ssp-buffer-size=1 -Weverything -Werror -std=c11 -fsanitize=undefined -fsanitize-trap=undefined -Wl,-z,relro,-z,now
 CFLAGS += -Wno-disabled-macro-expansion
 
 .PHONY: all clean clang-analyze cov-build install uninstall

src/enlighten.c

@@ -31,14 +31,31 @@ bl_get (const char * path) {
     return bness;
 }
 
+struct brightness_cmd
+bl_cmd_parse (const char * string) {
+
+    char sign [] = { 0, 0 }, perc [] = { 0, 0 };
+    signed bness = 0;
+
+    sscanf(string, "%1[+-]", sign);
+    if ( sscanf(string, "%d", &bness) != 1 ) {
+        sign[0] = '!';
+    }
+    sscanf(string, "%*d%1[%]", perc);
+
+    return (struct brightness_cmd ){ .bness = bness
+                                   , .sign = sign[0]
+                                   , .perc = perc[0] == '%' };
+}
+
 unsigned
-bl_calc (signed bness, bool sign, bool perc, unsigned cur, unsigned max) {
+bl_calc (struct brightness_cmd cmd, unsigned cur, unsigned max) {
 
-    if ( perc ) {
-        bness = bness * (signed )max / 100;
+    if ( cmd.perc ) {
+        cmd.bness = cmd.bness * (signed )max / 100;
     }
 
-    return (unsigned )(bness + sign * (signed )cur);
+    return (unsigned )(cmd.bness + (cmd.sign != '!') * (signed )cur);
 }
 
 void
@@ -69,11 +86,11 @@ main (signed argc, const char * argv []) {
     dev = dev ? dev : D_DEV;
 
     const char * thresh_top = 0;
-    thresh_top = getenv("BACKLIGHT_THRESHOLD_TOP");
+    thresh_top = getenv("BACKLIGHT_THRESHOLD_MAX");
     thresh_top = thresh_top ? thresh_top : THRESH_TOP;
 
     const char * thresh_bot = 0;
-    thresh_bot = getenv("BACKLIGHT_THRESHOLD_BOT");
+    thresh_bot = getenv("BACKLIGHT_THRESHOLD_MIN");
     thresh_bot = thresh_bot ? thresh_bot : THRESH_BOT;
 
     size_t blen = 33 + strlen(dev);
@@ -110,18 +127,21 @@ main (signed argc, const char * argv []) {
         }
     }
 
-    char sign [] = { 0, 0 }, perc [] = { 0, 0 };
-    signed bness = 0;
-    sscanf(argv[1], "%1[+-]", sign);
-    if ( sscanf(argv[1], "%d", &bness) != 1 ) {
+    struct brightness_cmd cmd = bl_cmd_parse(argv[1]);
+    if ( cmd.sign == '!' ) {
         fputs(USAGE_STR, stderr);
         status = EXIT_FAILURE;
         goto cleanup;
     }
 
-    sscanf(argv[1], "%*d%1[%]", perc);
+    unsigned ciel = bl_calc(bl_cmd_parse(thresh_top), 0, max),
+             floo = bl_calc(bl_cmd_parse(thresh_bot), 0, max);
+
+    unsigned nbness = bl_calc(cmd, cur, max);
+
+    nbness = nbness > ciel ? ciel :
+             nbness < floo ? floo : nbness;
 
-    unsigned nbness = bl_calc(bness, sign[0], perc[0] == '%', cur, max);
     bl_set(bpath, nbness);
 
     cleanup:

src/enlighten.h

@@ -26,18 +26,26 @@ static const char USAGE_STR [] =
     "  if + or - is specified, increment or\n"
     "  decrement accordingly\n\n"
     "  if % is specified, treat int as a\n"
-    "  percentage of the max brightness\n\n"
-    "set the BACKLIGHT_DEVICE environment variable\n"
-    "to specify a device name at runtime\n";
+    "  percentage of the max brightness\n"
+    "\nsee " PROGNAME "(1) for more usage information\n"
+    ;
+
+struct brightness_cmd {
+    signed bness;
+    signed sign: 16, perc: 16;
+};
 
 void
 bl_set (const char *, unsigned);
 
 unsigned
 bl_get (const char *);
 
+struct brightness_cmd
+bl_cmd_parse (const char *);
+
 unsigned
-bl_calc (signed, bool, bool, unsigned, unsigned);
+bl_calc (struct brightness_cmd, unsigned, unsigned);
 
 void
 bl_list (const char *);