diff options
Diffstat (limited to 'src/cmd/mk/varsub.c')
| -rw-r--r-- | src/cmd/mk/varsub.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/src/cmd/mk/varsub.c b/src/cmd/mk/varsub.c new file mode 100644 index 00000000..2a9ad987 --- /dev/null +++ b/src/cmd/mk/varsub.c @@ -0,0 +1,256 @@ +#include "mk.h" + +static Word *subsub(Word*, char*, char*); +static Word *expandvar(char**); +static Bufblock *varname(char**); +static Word *extractpat(char*, char**, char*, char*); +static int submatch(char*, Word*, Word*, int*, char**); +static Word *varmatch(char *, char**); + +Word * +varsub(char **s) +{ + Bufblock *b; + Word *w; + + if(**s == '{') /* either ${name} or ${name: A%B==C%D}*/ + return expandvar(s); + + b = varname(s); + if(b == 0) + return 0; + + w = varmatch(b->start, s); + freebuf(b); + return w; +} + +/* + * extract a variable name + */ +static Bufblock* +varname(char **s) +{ + Bufblock *b; + char *cp; + Rune r; + int n; + + b = newbuf(); + cp = *s; + for(;;){ + n = chartorune(&r, cp); + if (!WORDCHR(r)) + break; + rinsert(b, r); + cp += n; + } + if (b->current == b->start){ + SYNERR(-1); + fprint(2, "missing variable name <%s>\n", *s); + freebuf(b); + return 0; + } + *s = cp; + insert(b, 0); + return b; +} + +static Word* +varmatch(char *name, char **s) +{ + Word *w; + Symtab *sym; + char *cp; + + sym = symlook(name, S_VAR, 0); + if(sym){ + /* check for at least one non-NULL value */ + for (w = (Word*)sym->value; w; w = w->next) + if(w->s && *w->s) + return wdup(w); + } + for(cp = *s; *cp == ' ' || *cp == '\t'; cp++) /* skip trailing whitespace */ + ; + *s = cp; + return 0; +} + +static Word* +expandvar(char **s) +{ + Word *w; + Bufblock *buf; + Symtab *sym; + char *cp, *begin, *end; + + begin = *s; + (*s)++; /* skip the '{' */ + buf = varname(s); + if (buf == 0) + return 0; + cp = *s; + if (*cp == '}') { /* ${name} variant*/ + (*s)++; /* skip the '}' */ + w = varmatch(buf->start, s); + freebuf(buf); + return w; + } + if (*cp != ':') { + SYNERR(-1); + fprint(2, "bad variable name <%s>\n", buf->start); + freebuf(buf); + return 0; + } + cp++; + end = charin(cp , "}"); + if(end == 0){ + SYNERR(-1); + fprint(2, "missing '}': %s\n", begin); + Exit(); + } + *end = 0; + *s = end+1; + + sym = symlook(buf->start, S_VAR, 0); + if(sym == 0 || sym->value == 0) + w = newword(buf->start); + else + w = subsub((Word*) sym->value, cp, end); + freebuf(buf); + return w; +} + +static Word* +extractpat(char *s, char **r, char *term, char *end) +{ + int save; + char *cp; + Word *w; + + cp = charin(s, term); + if(cp){ + *r = cp; + if(cp == s) + return 0; + save = *cp; + *cp = 0; + w = stow(s); + *cp = save; + } else { + *r = end; + w = stow(s); + } + return w; +} + +static Word* +subsub(Word *v, char *s, char *end) +{ + int nmid; + Word *head, *tail, *w, *h; + Word *a, *b, *c, *d; + Bufblock *buf; + char *cp, *enda; + + a = extractpat(s, &cp, "=%&", end); + b = c = d = 0; + if(PERCENT(*cp)) + b = extractpat(cp+1, &cp, "=", end); + if(*cp == '=') + c = extractpat(cp+1, &cp, "&%", end); + if(PERCENT(*cp)) + d = stow(cp+1); + else if(*cp) + d = stow(cp); + + head = tail = 0; + buf = newbuf(); + for(; v; v = v->next){ + h = w = 0; + if(submatch(v->s, a, b, &nmid, &enda)){ + /* enda points to end of A match in source; + * nmid = number of chars between end of A and start of B + */ + if(c){ + h = w = wdup(c); + while(w->next) + w = w->next; + } + if(PERCENT(*cp) && nmid > 0){ + if(w){ + bufcpy(buf, w->s, strlen(w->s)); + bufcpy(buf, enda, nmid); + insert(buf, 0); + free(w->s); + w->s = strdup(buf->start); + } else { + bufcpy(buf, enda, nmid); + insert(buf, 0); + h = w = newword(buf->start); + } + buf->current = buf->start; + } + if(d && *d->s){ + if(w){ + + bufcpy(buf, w->s, strlen(w->s)); + bufcpy(buf, d->s, strlen(d->s)); + insert(buf, 0); + free(w->s); + w->s = strdup(buf->start); + w->next = wdup(d->next); + while(w->next) + w = w->next; + buf->current = buf->start; + } else + h = w = wdup(d); + } + } + if(w == 0) + h = w = newword(v->s); + + if(head == 0) + head = h; + else + tail->next = h; + tail = w; + } + freebuf(buf); + delword(a); + delword(b); + delword(c); + delword(d); + return head; +} + +static int +submatch(char *s, Word *a, Word *b, int *nmid, char **enda) +{ + Word *w; + int n; + char *end; + + n = 0; + for(w = a; w; w = w->next){ + n = strlen(w->s); + if(strncmp(s, w->s, n) == 0) + break; + } + if(a && w == 0) /* a == NULL matches everything*/ + return 0; + + *enda = s+n; /* pointer to end a A part match */ + *nmid = strlen(s)-n; /* size of remainder of source */ + end = *enda+*nmid; + for(w = b; w; w = w->next){ + n = strlen(w->s); + if(strcmp(w->s, end-n) == 0){ + *nmid -= n; + break; + } + } + if(b && w == 0) /* b == NULL matches everything */ + return 0; + return 1; +} |