From 695d95df19b74485be62aba0f978044ff1215ea0 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 20 Nov 2014 10:17:05 -0500 Subject: [PATCH] parse_color: refactor color storage When we parse a color name like "red" into its ANSI color value, we pack the storage into a single int that may take on many values: 1. If it's "-2", no value has been specified. 2. If it's "-1", the value is "normal" (i.e., no color). 3. If it's 0 through 7, the value is a standard ANSI color. 4. If it's larger (up to 255), it is a 256-color extended value. Given these magic numbers, it is often hard to see what is going on in the code. Let's refactor this into a struct with a flag that tells which scheme we are using, along with a numeric value. This is more verbose, but should hopefully be simpler to follow. It will also allow us to easily add support for more schemes, like 24-bit RGB values. The result is also slightly less efficient to store, but that's OK; we only store this intermediate state during the parse, after which we write out the actual ANSI bytes. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- color.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 106 insertions(+), 32 deletions(-) diff --git a/color.c b/color.c index 7941e932d2..3afda9d9dc 100644 --- a/color.c +++ b/color.c @@ -26,23 +26,77 @@ const char *column_colors_ansi[] = { /* Ignore the RESET at the end when giving the size */ const int column_colors_ansi_max = ARRAY_SIZE(column_colors_ansi) - 1; -static int parse_color(const char *name, int len) +/* An individual foreground or background color. */ +struct color { + enum { + COLOR_UNSPECIFIED = 0, + COLOR_NORMAL, + COLOR_ANSI, /* basic 0-7 ANSI colors */ + COLOR_256 + } type; + /* The numeric value for ANSI and 256-color modes */ + unsigned char value; +}; + +/* + * "word" is a buffer of length "len"; does it match the NUL-terminated + * "match" exactly? + */ +static int match_word(const char *word, int len, const char *match) { + return !strncasecmp(word, match, len) && !match[len]; +} + +static int parse_color(struct color *out, const char *name, int len) +{ + /* Positions in array must match ANSI color codes */ static const char * const color_names[] = { - "normal", "black", "red", "green", "yellow", + "black", "red", "green", "yellow", "blue", "magenta", "cyan", "white" }; char *end; int i; + long val; + + /* First try the special word "normal"... */ + if (match_word(name, len, "normal")) { + out->type = COLOR_NORMAL; + return 0; + } + + /* Then pick from our human-readable color names... */ for (i = 0; i < ARRAY_SIZE(color_names); i++) { - const char *str = color_names[i]; - if (!strncasecmp(name, str, len) && !str[len]) - return i - 1; + if (match_word(name, len, color_names[i])) { + out->type = COLOR_ANSI; + out->value = i; + return 0; + } } - i = strtol(name, &end, 10); - if (end - name == len && i >= -1 && i <= 255) - return i; - return -2; + + /* And finally try a literal 256-color-mode number */ + val = strtol(name, &end, 10); + if (end - name == len) { + /* + * Allow "-1" as an alias for "normal", but other negative + * numbers are bogus. + */ + if (val < -1) + ; /* fall through to error */ + else if (val < 0) { + out->type = COLOR_NORMAL; + return 0; + /* Rewrite low numbers as more-portable standard colors. */ + } else if (val < 8) { + out->type = COLOR_ANSI; + out->value = val; + } else if (val < 256) { + out->type = COLOR_256; + out->value = val; + return 0; + } + } + + return -1; } static int parse_attr(const char *name, int len) @@ -65,13 +119,43 @@ int color_parse(const char *value, char *dst) return color_parse_mem(value, strlen(value), dst); } +#define COLOR_FOREGROUND '3' +#define COLOR_BACKGROUND '4' + +/* + * Write the ANSI color codes for "c" to "out"; the string should + * already have the ANSI escape code in it. "out" should have enough + * space in it to fit any color. + */ +static char *color_output(char *out, const struct color *c, char type) +{ + switch (c->type) { + case COLOR_UNSPECIFIED: + case COLOR_NORMAL: + break; + case COLOR_ANSI: + *out++ = type; + *out++ = '0' + c->value; + break; + case COLOR_256: + out += sprintf(out, "%c8;5;%d", type, c->value); + break; + } + return out; +} + +static int color_empty(const struct color *c) +{ + return c->type <= COLOR_NORMAL; +} + int color_parse_mem(const char *value, int value_len, char *dst) { const char *ptr = value; int len = value_len; unsigned int attr = 0; - int fg = -2; - int bg = -2; + struct color fg = { COLOR_UNSPECIFIED }; + struct color bg = { COLOR_UNSPECIFIED }; if (!strncasecmp(value, "reset", len)) { strcpy(dst, GIT_COLOR_RESET); @@ -81,6 +165,7 @@ int color_parse_mem(const char *value, int value_len, char *dst) /* [fg [bg]] [attr]... */ while (len > 0) { const char *word = ptr; + struct color c; int val, wordlen = 0; while (len > 0 && !isspace(word[wordlen])) { @@ -94,14 +179,13 @@ int color_parse_mem(const char *value, int value_len, char *dst) len--; } - val = parse_color(word, wordlen); - if (val >= -1) { - if (fg == -2) { - fg = val; + if (!parse_color(&c, word, wordlen)) { + if (fg.type == COLOR_UNSPECIFIED) { + fg = c; continue; } - if (bg == -2) { - bg = val; + if (bg.type == COLOR_UNSPECIFIED) { + bg = c; continue; } goto bad; @@ -113,7 +197,7 @@ int color_parse_mem(const char *value, int value_len, char *dst) goto bad; } - if (attr || fg >= 0 || bg >= 0) { + if (attr || !color_empty(&fg) || !color_empty(&bg)) { int sep = 0; int i; @@ -129,25 +213,15 @@ int color_parse_mem(const char *value, int value_len, char *dst) *dst++ = ';'; *dst++ = '0' + i; } - if (fg >= 0) { + if (!color_empty(&fg)) { if (sep++) *dst++ = ';'; - if (fg < 8) { - *dst++ = '3'; - *dst++ = '0' + fg; - } else { - dst += sprintf(dst, "38;5;%d", fg); - } + dst = color_output(dst, &fg, COLOR_FOREGROUND); } - if (bg >= 0) { + if (!color_empty(&bg)) { if (sep++) *dst++ = ';'; - if (bg < 8) { - *dst++ = '4'; - *dst++ = '0' + bg; - } else { - dst += sprintf(dst, "48;5;%d", bg); - } + dst = color_output(dst, &bg, COLOR_BACKGROUND); } *dst++ = 'm'; } -- 2.11.4.GIT