color.c

   1 /** \file color.c Functions for printing colored messages. */
   2
   3 /*
   4  * Mostly taken from the git source tree, version 1.6.1.76, January 2009.
   5  */
   6
   7 #include "para.h"
   8 #include "color.h"
   9
  10 static int parse_color(const char *name, int len)
  11 {
  12         static const char * const color_names[] = {
  13                 "normal", "black", "red", "green", "yellow",
  14                 "blue", "magenta", "cyan", "white"
  15         };
  16         char *end;
  17         int i;
  18         for (i = 0; i < ARRAY_SIZE(color_names); i++) {
  19                 const char *str = color_names[i];
  20                 if (!strncasecmp(name, str, len) && !str[len])
  21                         return i - 1;
  22         }
  23         i = strtol(name, &end, 10);
  24         if (end - name == len && i >= -1 && i <= 255)
  25                 return i;
  26         return -2;
  27 }
  28
  29 static int parse_attr(const char *name, int len)
  30 {
  31         static const int attr_values[] = { 1, 2, 4, 5, 7 };
  32         static const char * const attr_names[] = {
  33                 "bold", "dim", "ul", "blink", "reverse"
  34         };
  35         int i;
  36         for (i = 0; i < ARRAY_SIZE(attr_names); i++) {
  37                 const char *str = attr_names[i];
  38                 if (!strncasecmp(name, str, len) && !str[len])
  39                         return attr_values[i];
  40         }
  41         return -1;
  42 }
  43
  44 /**
  45  * Create an escape sequence for colored output.
  46  *
  47  * \param value Human-readable color spec.
  48  * \param dst Result pointer for the escape sequence.
  49  *
  50  * \return -1 on errors, 1 on success.
  51  *
  52  * Format of \a value: [fg [bg]] [attr].
  53  */
  54 int color_parse(const char *value, char *dst)
  55 {
  56         const char *ptr = value;
  57         int attr = -1;
  58         int fg = -2;
  59         int bg = -2;
  60
  61         if (!strcasecmp(value, "reset")) {
  62                 strcpy(dst, COLOR_RESET);
  63                 return 1;
  64         }
  65
  66         /* [fg [bg]] [attr] */
  67         while (*ptr) {
  68                 const char *word = ptr;
  69                 int val, len = 0;
  70
  71                 while (word[len] && !para_isspace(word[len]))
  72                         len++;
  73
  74                 ptr = word + len;
  75                 while (*ptr && para_isspace(*ptr))
  76                         ptr++;
  77
  78                 val = parse_color(word, len);
  79                 if (val >= -1) {
  80                         if (fg == -2) {
  81                                 fg = val;
  82                                 continue;
  83                         }
  84                         if (bg == -2) {
  85                                 bg = val;
  86                                 continue;
  87                         }
  88                         goto bad;
  89                 }
  90                 val = parse_attr(word, len);
  91                 if (val < 0 || attr != -1)
  92                         goto bad;
  93                 attr = val;
  94         }
  95
  96         if (attr >= 0 || fg >= 0 || bg >= 0) {
  97                 int sep = 0;
  98
  99                 *dst++ = '\033';
 100                 *dst++ = '[';
 101                 if (attr >= 0) {
 102                         *dst++ = '0' + attr;
 103                         sep++;
 104                 }
 105                 if (fg >= 0) {
 106                         if (sep++)
 107                                 *dst++ = ';';
 108                         if (fg < 8) {
 109                                 *dst++ = '3';
 110                                 *dst++ = '0' + fg;
 111                         } else {
 112                                 dst += sprintf(dst, "38;5;%d", fg);
 113                         }
 114                 }
 115                 if (bg >= 0) {
 116                         if (sep)
 117                                 *dst++ = ';';
 118                         if (bg < 8) {
 119                                 *dst++ = '4';
 120                                 *dst++ = '0' + bg;
 121                         } else {
 122                                 dst += sprintf(dst, "48;5;%d", bg);
 123                         }
 124                 }
 125                 *dst++ = 'm';
 126         }
 127         *dst = 0;
 128         return 1;
 129 bad:
 130         PARA_ERROR_LOG("bad color value '%s'\n", value);
 131         return -1;
 132 }