diff options
Diffstat (limited to 'toys')
-rw-r--r-- | toys/posix/expand.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/toys/posix/expand.c b/toys/posix/expand.c new file mode 100644 index 00000000..739c326d --- /dev/null +++ b/toys/posix/expand.c @@ -0,0 +1,141 @@ +/* expand.c - expands tabs to space + * + * FIXME: handle backspace. + * + * Copyright 2012 Jonathan Clairembault <jonathan at clairembault dot fr> + * + * See http://http://pubs.opengroup.org/onlinepubs/9699919799/nframe.html + +USE_EXPAND(NEWTOY(expand, "t:", TOYFLAG_USR|TOYFLAG_BIN)) + +config EXPAND + bool "expand" + default n + help + usage: expand [-t tablist] [file...] + + Command expand. Expands tabs to space according to tabstops. + + -t tablist + Specify the tab stops. The argument tablist consists of either a single + strictly positive decimal integer or a list of tabstops. If a single number + is given, tabs are set that number of column positions apart instead of the + default 8. + + If a list of tabstops is given, the list is made of two or more strictly + positive decimal integers, separated by <blank> or <comma> characters, in + strictly ascending order. The <tab> characters are set at those specific + column positions. + + In the event of expand having to process a <tab> at a position beyond the + last of those specified in a multiple tab-stop list, the <tab> is replaced + by a single <space> in the output. + + Any <backspace> characters shall be copied to the output and cause the + column position count for tab stop calculations to be decremented; the + column position count shall not be decremented below zero. +*/ + +#define FOR_expand +#include "toys.h" + +GLOBALS( + char *t_flags; + struct offset_list tablist; +) + +static void build_tablist(char *tabstops) +{ + char *ctx; + struct offset_list *tablist = &TT.tablist; + char *s, *ref; + off_t stop, last_stop; + + /* for every tabstop decode and add to list */ + for (stop = last_stop = 0, s = ref = xstrdup(tabstops); ; + last_stop = stop, s = NULL) { + char *tabstop = strtok_r(s, " ,", &ctx); + + if (!tabstop) return; + + stop = xstrtoul(tabstop, NULL, 0); + if (stop <= last_stop) { + free(ref); + toys.exithelp = 1; + error_exit("tablist ascending order"); + } + tablist->next = xzalloc(sizeof(*tablist)); + tablist->next->off = stop; + tablist = tablist->next; + } + + free(ref); +} + +static void expand_file(int fd, char *name) +{ + ssize_t rdn; + char *rdbuf, *wrbuf; + size_t wrbuflen, rdbuflen; + ssize_t rdbufi = 0, wrbufi = 0; + ssize_t wrlinei; + int hastablist = !!TT.tablist.next->next; + struct offset_list *tablist = TT.tablist.next; + ssize_t stop = tablist->off; + + wrbuflen = rdbuflen = ARRAY_LEN(toybuf)/2; + rdbuf = toybuf; + wrbuf = toybuf + rdbuflen; + do { + rdn = readall(fd, rdbuf, rdbuflen); + if (rdn < 0) perror_exit("%s", name); + for (rdbufi=0, wrbufi=0; rdbufi<rdn; rdbufi++) { + if (wrbufi == wrbuflen) { /* flush expand buffer when full */ + writeall(STDOUT_FILENO, wrbuf, wrbuflen); + wrbufi = 0; + } + if (rdbuf[rdbufi] == '\t') { /* expand tab */ + size_t count; + size_t tabsize; + + /* search next tab stop */ + while(tablist && (stop <= wrlinei)) { + stop = hastablist ? tablist->off : stop + tablist->off; + tablist = hastablist ? tablist->next : tablist; + } + tabsize = ((stop - wrlinei < 2)) ? 1 : stop - wrlinei; + while (tabsize) { /* long expand */ + count = min(tabsize, wrbuflen - wrbufi); + memset(wrbuf + wrbufi, ' ', count); + tabsize -= count; + if (tabsize) { /* flush expand buffer when full */ + writeall(STDOUT_FILENO, wrbuf, wrbuflen); + wrbufi = 0; + } else wrbufi += count; + } + wrlinei += count; + } else { /* copy input to output */ + wrbuf[wrbufi++] = rdbuf[rdbufi]; + wrlinei += 1; + /* flush expand buffer and reset tablist at newline */ + if (rdbuf[rdbufi] == '\n') { + writeall(STDOUT_FILENO, wrbuf, wrbufi); + tablist = TT.tablist.next; + stop = tablist->off; + wrbufi = wrlinei = 0; + } + } + } + } while (rdn == rdbuflen); + /* flush last expand buffer */ + writeall(STDOUT_FILENO, wrbuf, wrbufi); +} + +void expand_main(void) +{ + build_tablist((toys.optflags & FLAG_t) ? TT.t_flags : "8"); + /* expand every file */ + loopfiles(toys.optargs, expand_file); + /* free tablist */ + llist_traverse(TT.tablist.next, free); +} |