From df6393be75b8b09184426269135e031bda0e8621 Mon Sep 17 00:00:00 2001
From: "Dmitrij D. Czarkoff" <czarkoff@gmail.com>
Date: Sun, 23 Oct 2016 03:32:58 +0200
Subject: Simplify hex color parser

It is actually a trivial task for strtoul + some bit shifting, so there is no
need for two separate functions.
---
 src/main.c | 11 +++++++----
 src/util.c | 34 ----------------------------------
 src/util.h |  4 ----
 3 files changed, 7 insertions(+), 42 deletions(-)

diff --git a/src/main.c b/src/main.c
index 2671a21..21fbc77 100644
--- a/src/main.c
+++ b/src/main.c
@@ -103,7 +103,7 @@ static void parse_args(int argc, char** argv)
   /* Do not print getopt errors */
   opterr = 0;
 
-  char *argp, o;
+  char *argp, *ep = *argv, o;
 
   while((o = getopt(argc, argv, "firasSudxhln:b:e:t:")) != -1) {
     switch(o) {
@@ -129,11 +129,15 @@ static void parse_args(int argc, char** argv)
           g_options.solid_bg = 0;
         } else {
           g_options.solid_bg = 1;
-          if(parse_hex_color(optarg,
-              &g_options.bg_r, &g_options.bg_g, &g_options.bg_b) != 0) {
+          argp = (*optarg == '#') ? optarg + 1 : optarg;
+          uint32_t n = strtoul(argp, &ep, 16);
+          if(*ep != '\0' || ep - argp != 6 || n > 0xFFFFFF) {
             fprintf(stderr, "Invalid hex color: '%s'\n", optarg);
             exit(1);
           }
+          g_options.bg_b = n & 0xFF;
+          g_options.bg_g = (n >> 8) & 0xFF;
+          g_options.bg_r = (n >> 16);
         }
         break;
       case 'e':
@@ -143,7 +147,6 @@ static void parse_args(int argc, char** argv)
         g_options.delay = strtoul(optarg, &argp, 10);
         g_options.delay *= 1000;
         if (*argp == '.') {
-          char *ep;
           long delay = strtoul(++argp, &ep, 10);
           for (int i = 3 - (ep - argp); i; i--) {
             delay *= 10;
diff --git a/src/util.c b/src/util.c
index 9294f51..75d6910 100644
--- a/src/util.c
+++ b/src/util.c
@@ -124,40 +124,6 @@ SDL_Texture *create_chequered(SDL_Renderer *renderer)
   return ret;
 }
 
-static int parse_hex_digit(char c) {
-  if(c >= '0' && c <= '9') {
-    return c - '0';
-  } else if (c >= 'a' && c <= 'f') {
-    return c - 'a' + 10;
-  } else if (c >= 'A' && c <= 'F') {
-    return c - 'A' + 10;
-  }
-  return -1;
-}
-
-int parse_hex_color(const char* str,
-  unsigned char *r, unsigned char *g, unsigned char *b)
-{
-  if(str[0] == '#') {
-    ++str;
-  }
-
-  if(strlen(str) != 6) {
-    return 1;
-  }
-
-  for(int i = 0; i < 6; ++i) {
-    if(!isxdigit(str[i])) {
-      return 1;
-    }
-  }
-
-  *r = (parse_hex_digit(str[0]) << 4) + parse_hex_digit(str[1]);
-  *g = (parse_hex_digit(str[2]) << 4) + parse_hex_digit(str[3]);
-  *b = (parse_hex_digit(str[4]) << 4) + parse_hex_digit(str[5]);
-  return 0;
-}
-
 void imv_printf(SDL_Renderer *renderer, TTF_Font *font, int x, int y,
                 SDL_Color *fg, SDL_Color *bg, const char *fmt, ...)
 {
diff --git a/src/util.h b/src/util.h
index 039d55f..652c5be 100644
--- a/src/util.h
+++ b/src/util.h
@@ -27,10 +27,6 @@ size_t read_from_stdin(void **buffer);
 /* Creates a new SDL_Texture* containing a chequeboard texture */
 SDL_Texture *create_chequered(SDL_Renderer *renderer);
 
-/* Parses a triplet of hexadecimal bytes. Writes values to r, g, and b. */
-int parse_hex_color(const char* str,
-  unsigned char *r, unsigned char *g, unsigned char *b);
-
 /* Loads a font using SDL2_ttf given a spec in the format "name:size" */
 TTF_Font *load_font(const char *font_spec);
 
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