diff options
Diffstat (limited to 'Src/subst.c')
| -rw-r--r-- | Src/subst.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/Src/subst.c b/Src/subst.c index 5f65945a5..c0fb38a48 100644 --- a/Src/subst.c +++ b/Src/subst.c @@ -1371,6 +1371,43 @@ untok_and_escape(char *s, int escapes, int tok_arg) return dst; } +/* + * See if an argument str looks like a subscript or length following + * a colon and parse it. It must be followed by a ':' or nothing. + * If this succeeds, expand and return the evaulated expression if + * found, else return NULL. + * + * We assume this is what is meant if the first character is not + * an alphabetic character or '&', which signify modifiers. + * + * Set *endp to point to the next character following. + */ +static char * +check_colon_subscript(char *str, char **endp) +{ + int sav; + + /* Could this be a modifier (or empty)? */ + if (!*str || ialpha(*str) || *str == '&') + return NULL; + + *endp = parse_subscript(str, 0, ':'); + if (!*endp) { + /* No trailing colon? */ + *endp = parse_subscript(str, 0, '\0'); + if (!*endp) + return NULL; + } + sav = **endp; + **endp = '\0'; + if (parsestr(str = dupstring(str))) + return NULL; + singsub(&str); + + **endp = sav; + return str; +} + /* parameter substitution */ #define isstring(c) ((c) == '$' || (char)(c) == String || (char)(c) == Qstring) @@ -2683,6 +2720,97 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int ssub) } val = dupstring(""); } + if (colf && inbrace) { + /* + * Look for ${PARAM:OFFSET} or ${PARAM:OFFSET:LENGTH}. + * This must appear before modifiers. For compatibility + * with bash we perform both standard string substitutions + * and math eval. + */ + char *check_offset2; + char *check_offset = check_colon_subscript(s, &check_offset2); + if (check_offset) { + zlong offset = mathevali(check_offset); + zlong length = (zlong)-1; + if (errflag) + return NULL; + if ((*check_offset2 && *check_offset2 != ':')) { + zerr("invalid subscript: %s", check_offset); + return NULL; + } + if (*check_offset2) { + check_offset = check_colon_subscript(check_offset2 + 1, + &check_offset2); + if (*check_offset2 && *check_offset2 != ':') { + zerr("invalid length: %s", check_offset); + return NULL; + } + length = mathevali(check_offset); + if (errflag) + return NULL; + if (length < (zlong)0) { + zerr("invalid length: %s", check_offset); + return NULL; + } + } + if (!isset(KSHARRAYS) && offset > 0) + offset--; + if (isarr) { + int alen = arrlen(aval), count; + char **srcptr, **dstptr, **newarr; + + if (offset < 0) { + offset += alen; + if (offset < 0) + offset = 0; + } + if (length < 0) + length = alen; + if (offset > alen) + offset = alen; + if (offset + length > alen) + length = alen - offset; + count = length; + srcptr = aval + offset; + newarr = dstptr = (char **) + zhalloc((length+1)*sizeof(char *)); + while (count--) + *dstptr++ = dupstring(*srcptr++); + *dstptr = (char *)NULL; + aval = newarr; + } else { + char *sptr, *eptr; + if (offset < 0) { + MB_METACHARINIT(); + for (sptr = val; *sptr; ) { + sptr += MB_METACHARLEN(sptr); + offset++; + } + if (offset < 0) + offset = 0; + } + MB_METACHARINIT(); + for (sptr = val; *sptr && offset; ) { + sptr += MB_METACHARLEN(sptr); + offset--; + } + if (length >= 0) { + for (eptr = sptr; *eptr && length; ) { + eptr += MB_METACHARLEN(eptr); + length--; + } + val = dupstrpfx(sptr, eptr - sptr); + } else { + val = dupstring(sptr); + } + } + if (!*check_offset2) { + colf = 0; + } else { + s = check_offset2 + 1; + } + } + } if (colf) { /* * History style colon modifiers. May need to apply |