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/* ISC license. */
#include <string.h>
#include <skalibs/bytestr.h>
#include <skalibs/stralloc.h>
#include <skalibs/genalloc.h>
#include <execline/execline.h>
typedef struct elsubsu_s elsubsu_t, *elsubsu_t_ref ;
struct elsubsu_s
{
elsubst_t const *subst ;
size_t pos ;
} ;
typedef struct subsuinfo_s subsuinfo_t, *subsuinfo_t_ref ;
struct subsuinfo_s
{
stralloc dst ;
stralloc sa ;
genalloc list ; /* array of elsubsu_t */
char const *values ;
} ;
#define SUBSUINFO_ZERO { .dst = STRALLOC_ZERO, .sa = STRALLOC_ZERO, .list = GENALLOC_ZERO, .values = 0 }
#define TEST 0x80
#define MARK 0x40
#define KEEPESC 0x20
#define INCRESC 0x10
#define STATE 0x07
#define INWORD 0x00
#define INDOLL 0x01
#define INDBR 0x02
#define INVAR 0x03
#define INVARBR 0x04
#define ACCEPT 0x05
static ssize_t parseword (stralloc *sa, genalloc *list, char const *s, char const *vars, elsubst_t const *substs, unsigned int nsubst)
{
static char const class[5] = "\0\\${}" ;
static unsigned char const table[6][5] =
{
{ ACCEPT, ACCEPT, ACCEPT, ACCEPT | TEST, ACCEPT },
{ INWORD | KEEPESC | INCRESC, INWORD | INCRESC, INWORD | INCRESC, INWORD | TEST | INCRESC, INWORD | INCRESC },
{ INDOLL | KEEPESC, INDOLL, INDOLL, INDOLL | TEST, INDOLL },
{ INWORD, INDBR | KEEPESC, INWORD, INWORD | TEST, INWORD },
{ INWORD, INWORD, INWORD, INWORD | TEST, INWORD | TEST },
{ INWORD, INVAR | MARK | KEEPESC, INVARBR | MARK | KEEPESC, INVAR | KEEPESC, INVARBR | KEEPESC }
} ;
size_t mark = 0, offset = 0, esc = 0, salen = sa->len, listlen = genalloc_len(elsubsu_t, list) ;
ssize_t pos = 0 ;
unsigned char state = INWORD ;
while (state != ACCEPT)
{
int nopush = 0 ;
unsigned char c = table[byte_chr(class, 5, s[pos])][state] ;
if (c & TEST)
{
unsigned int supp = (state == INVARBR) ;
unsigned int i = 0 ;
for (; i < nsubst ; i++)
{
if (!strncmp(vars + substs[i].var, s + mark, pos - mark) && !vars[substs[i].var + pos - mark])
{
sa->len -= esc >> 1 ; offset += esc >> 1 ;
if (esc & 1)
{
memmove(sa->s + mark - offset - 2 - supp, sa->s + mark - offset + (esc>>1) - 1 - supp, pos - mark + 1 + supp) ;
sa->len-- ; offset++ ;
}
else
{
elsubsu_t cur ;
cur.subst = substs + i ;
cur.pos = mark - offset - 1 - supp ;
if (!genalloc_append(elsubsu_t, list, &cur)) goto err ;
offset += sa->len - cur.pos ;
sa->len = cur.pos ;
if (supp) nopush = 1 ;
}
break ;
}
}
}
if (nopush) offset++ ;
else if (!stralloc_catb(sa, s+pos, 1)) goto err ;
if (c & MARK) mark = pos ;
if (!(c & KEEPESC)) esc = 0 ;
if (c & INCRESC) esc++ ;
state = c & STATE ; pos++ ;
}
sa->len-- ;
return pos ;
err:
sa->len = salen ;
list->len = listlen ;
return -1 ;
}
static int substword (subsuinfo_t *info, size_t wordstart, size_t wordlen, unsigned int n, size_t offset)
{
if (n < genalloc_len(elsubsu_t, &info->list))
{
elsubsu_t *list = genalloc_s(elsubsu_t, &info->list) ;
char const *p = info->values + list[n].subst->value ;
size_t l = list[n].pos + offset ;
size_t dstbase = info->dst.len ;
size_t sabase = info->sa.len ;
unsigned int i = 0 ;
int nc = 0 ;
if (!stralloc_readyplus(&info->sa, l)) return -1 ;
stralloc_catb(&info->sa, info->sa.s + wordstart, l) ;
for (; i < list[n].subst->n ; i++)
{
size_t plen = strlen(p) ;
int r ;
info->sa.len = sabase + l ;
if (!stralloc_readyplus(&info->sa, plen + wordlen - l)) goto err ;
stralloc_catb(&info->sa, p, plen) ;
stralloc_catb(&info->sa, info->sa.s + wordstart + l, wordlen - l) ;
r = substword(info, sabase, info->sa.len - sabase, n+1, offset + plen) ;
if (r < 0) goto err ;
nc += r ;
p += plen+1 ;
}
return nc ;
err:
info->sa.len = sabase ;
info->dst.len = dstbase ;
return -1 ;
}
else
{
if (!stralloc_readyplus(&info->dst, wordlen+1)) return -1 ;
stralloc_catb(&info->dst, info->sa.s + wordstart, wordlen) ;
stralloc_0(&info->dst) ;
return 1 ;
}
}
int el_substitute (stralloc *dst, char const *src, size_t len, char const *vars, char const *values, elsubst_t const *substs, unsigned int nsubst)
{
subsuinfo_t info = SUBSUINFO_ZERO ;
size_t i = 0 ;
size_t dstbase = dst->len ;
int nc = 0 ;
int wasnull = !dst->s ;
info.dst = *dst ;
info.values = values ;
while (i < len)
{
genalloc_setlen(elsubsu_t, &info.list, 0) ;
info.sa.len = 0 ;
{
ssize_t r = parseword(&info.sa, &info.list, src + i, vars, substs, nsubst) ;
if (r < 0) goto err ;
i += r ;
}
{
int r = substword(&info, 0, info.sa.len, 0, 0) ;
if (r < 0) goto err ;
nc += r ;
}
}
genalloc_free(elsubsu_t, &info.list) ;
stralloc_free(&info.sa) ;
if (!wasnull) stralloc_free(dst) ;
*dst = info.dst ;
return nc ;
err :
genalloc_free(elsubsu_t, &info.list) ;
stralloc_free(&info.sa) ;
if (wasnull) stralloc_free(&info.dst) ; else info.dst.len = dstbase ;
*dst = info.dst ;
return -1 ;
}
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