diff options
| -rw-r--r-- | miscutils/less.c | 45 |
1 files changed, 38 insertions, 7 deletions
diff --git a/miscutils/less.c b/miscutils/less.c index d6b71b9f2..58c1ec217 100644 --- a/miscutils/less.c +++ b/miscutils/less.c @@ -204,7 +204,27 @@ static void fill_match_lines(unsigned pos); #define fill_match_lines(pos) ((void)0) #endif - +/* Devilishly complex routine. + * + * Has to deal with EOF and EPIPE on input, + * with line wrapping, with last line not ending in '\n' + * (possibly not ending YET!), with backspace and tabs. + * + * Variables used: + * flines[] - array of lines already read. Linewrap may cause + * one source file line to occupy several flines[n]. + * flines[max_fline] - last line, possibly incomplete. + * terminated - 1 if flines[max_fline] is 'terminated' + * (if there was '\n' [which isn't stored itself, we just remember + * that it was seen]) + * max_lineno - last line's number, this one doesn't increment + * on line wrap, only on "real" new lines. + * readbuf[0..readeof-1] - small preliminary buffer. + * readbuf[readpos] - next character to add to current line. + * linepos - screen line position of next char to be read + * (takes into account tabs and backspaces) + * eof_error - < 0 error, == 0 EOF, > 0 not EOF/error + */ static void read_lines(void) { #define readbuf bb_common_bufsiz1 @@ -225,6 +245,7 @@ static void read_lines(void) cp += 8; strcpy(current_line, cp); p += strlen(current_line); + /* linepos is still valid from previous read_lines() */ } else { linepos = 0; } @@ -275,17 +296,27 @@ static void read_lines(void) if (c == '\x8' && linepos && p[-1] != '\t') { readpos++; /* eat it */ linepos--; + /* was buggy (p could end up <= current_line)... */ *--p = '\0'; continue; } - if (c == '\t') - linepos += (linepos^7) & 7; - linepos++; - if (linepos >= w) - break; + { + size_t new_linepos = linepos + 1; + if (c == '\t') { + new_linepos += 7; + new_linepos &= (~7); + } + if (new_linepos >= w) + break; + linepos = new_linepos; + } /* ok, we will eat this char */ readpos++; - if (c == '\n') { terminated = 1; break; } + if (c == '\n') { + terminated = 1; + linepos = 0; + break; + } /* NUL is substituted by '\n'! */ if (c == '\0') c = '\n'; *p++ = c; |