degrade some of the characters in a string */
| 117 | |
| 118 | /* degrade some of the characters in a string */ |
| 119 | void |
| 120 | wipeout_text( |
| 121 | char *engr, /* engraving text */ |
| 122 | int cnt, /* number of chars to degrade */ |
| 123 | unsigned seed) /* for semi-controlled randomization */ |
| 124 | { |
| 125 | char *s; |
| 126 | int i, j, nxt, use_rubout; |
| 127 | unsigned lth = (unsigned) strlen(engr); |
| 128 | |
| 129 | if (lth && cnt > 0) { |
| 130 | while (cnt--) { |
| 131 | /* pick next character */ |
| 132 | if (!seed) { |
| 133 | /* random */ |
| 134 | nxt = rn2((int) lth); |
| 135 | use_rubout = rn2(4); |
| 136 | } else { |
| 137 | /* predictable; caller can reproduce the same sequence by |
| 138 | supplying the same arguments later, or a pseudo-random |
| 139 | sequence by varying any of them */ |
| 140 | nxt = seed % lth; |
| 141 | seed *= 31, seed %= (BUFSZ - 1); |
| 142 | use_rubout = seed & 3; |
| 143 | } |
| 144 | s = &engr[nxt]; |
| 145 | if (*s == ' ') |
| 146 | continue; |
| 147 | |
| 148 | /* rub out unreadable & small punctuation marks */ |
| 149 | if (strchr("?.,'`-|_", *s)) { |
| 150 | *s = ' '; |
| 151 | continue; |
| 152 | } |
| 153 | |
| 154 | if (!use_rubout) { |
| 155 | i = SIZE(rubouts); |
| 156 | } else { |
| 157 | for (i = 0; i < SIZE(rubouts); i++) |
| 158 | if (*s == rubouts[i].wipefrom) { |
| 159 | unsigned ln = (unsigned) strlen(rubouts[i].wipeto); |
| 160 | /* |
| 161 | * Pick one of the substitutes at random. |
| 162 | */ |
| 163 | if (!seed) { |
| 164 | j = rn2((int) ln); |
| 165 | } else { |
| 166 | seed *= 31, seed %= (BUFSZ - 1); |
| 167 | j = seed % ln; |
| 168 | } |
| 169 | *s = rubouts[i].wipeto[j]; |
| 170 | break; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | /* didn't pick rubout; use '?' for unreadable character */ |
| 175 | if (i == SIZE(rubouts)) |
| 176 | *s = '?'; |
no test coverage detected