static int str_packsize (lua_State *L) {
Header h;
const char *fmt = luaL_checkstring(L, 1); /* format string */
size_t totalsize = 0; /* accumulate total size of result */
initheader(L, &h);
while (*fmt != '\0') {
int size, ntoalign;
KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
luaL_argcheck(L, opt != Kstring && opt != Kzstr, 1,
"variable-length format");
size += ntoalign; /* total space used by option */
luaL_argcheck(L, totalsize <= MAXSIZE - size, 1,
"format result too large");
totalsize += size;
}
lua_pushinteger(L, (lua_Integer)totalsize);
return 1;
}
static int str_packsize (lua_State *L) {
Header h;
const char *fmt = luaL_checkstring(L, 1); /* format string */
size_t totalsize = 0; /* accumulate total size of result */
initheader(L, &h);
while (*fmt != '\0') {
int size, ntoalign;
KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
size += ntoalign; /* total space used by option */
luaL_argcheck(L, totalsize <= MAXSIZE - size, 1,
"format result too large");
totalsize += size;
switch (opt) {
case Kstring: /* strings with length count */
case Kzstr: /* zero-terminated string */
luaL_argerror(L, 1, "variable-length format");
break;
default: break;
}
}
lua_pushinteger(L, (lua_Integer)totalsize);
return 1;
}
static int str_unpack (lua_State *L) {
Header h;
const char *fmt = luaL_checkstring(L, 1);
size_t ld;
const char *data = luaL_checklstring(L, 2, &ld);
size_t pos = (size_t)posrelat(luaL_optinteger(L, 3, 1), ld) - 1;
int n = 0; /* number of results */
luaL_argcheck(L, pos <= ld, 3, "initial position out of string");
initheader(L, &h);
while (*fmt != '\0') {
int size, ntoalign;
KOption opt = getdetails(&h, pos, &fmt, &size, &ntoalign);
luaL_argcheck(L, (size_t)ntoalign + size <= ld - pos, 2,
"data string too short");
pos += ntoalign; /* skip alignment */
/* stack space for item + next position */
luaL_checkstack(L, 2, "too many results");
n++;
switch (opt) {
case Kint:
case Kuint: {
lua_Integer res = unpackint(L, data + pos, h.islittle, size,
(opt == Kint));
lua_pushinteger(L, res);
break;
}
case Kfloat: {
volatile Ftypes u;
lua_Number num;
copywithendian(u.buff, data + pos, size, h.islittle);
if (size == sizeof(u.f)) num = (lua_Number)u.f;
else if (size == sizeof(u.d)) num = (lua_Number)u.d;
else num = u.n;
lua_pushnumber(L, num);
break;
}
case Kchar: {
lua_pushlstring(L, data + pos, size);
break;
}
case Kstring: {
size_t len = (size_t)unpackint(L, data + pos, h.islittle, size, 0);
luaL_argcheck(L, len <= ld - pos - size, 2, "data string too short");
lua_pushlstring(L, data + pos + size, len);
pos += len; /* skip string */
break;
}
case Kzstr: {
size_t len = (int)strlen(data + pos);
luaL_argcheck(L, pos + len < ld, 2,
"unfinished string for format 'z'");
lua_pushlstring(L, data + pos, len);
pos += len + 1; /* skip string plus final '\0' */
break;
}
case Kpaddalign: case Kpadding: case Knop:
n--; /* undo increment */
break;
}
pos += size;
}
lua_pushinteger(L, pos + 1); /* next position */
return n + 1;
}
static int str_pack (lua_State *L) {
luaL_Buffer b;
Header h;
const char *fmt = luaL_checkstring(L, 1); /* format string */
int arg = 1; /* current argument to pack */
size_t totalsize = 0; /* accumulate total size of result */
initheader(L, &h);
lua_pushnil(L); /* mark to separate arguments from string buffer */
luaL_buffinit(L, &b);
while (*fmt != '\0') {
int size, ntoalign;
KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
totalsize += ntoalign + size;
while (ntoalign-- > 0)
luaL_addchar(&b, LUAL_PACKPADBYTE); /* fill alignment */
arg++;
switch (opt) {
case Kint: { /* signed integers */
lua_Integer n = luaL_checkinteger(L, arg);
if (size < SZINT) { /* need overflow check? */
lua_Integer lim = (lua_Integer)1 << ((size * NB) - 1);
luaL_argcheck(L, -lim <= n && n < lim, arg, "integer overflow");
}
packint(&b, (lua_Unsigned)n, h.islittle, size, (n < 0));
break;
}
case Kuint: { /* unsigned integers */
lua_Integer n = luaL_checkinteger(L, arg);
if (size < SZINT) /* need overflow check? */
luaL_argcheck(L, (lua_Unsigned)n < ((lua_Unsigned)1 << (size * NB)),
arg, "unsigned overflow");
packint(&b, (lua_Unsigned)n, h.islittle, size, 0);
break;
}
case Kfloat: { /* floating-point options */
volatile Ftypes u;
char *buff = luaL_prepbuffsize(&b, size);
lua_Number n = luaL_checknumber(L, arg); /* get argument */
if (size == sizeof(u.f)) u.f = (float)n; /* copy it into 'u' */
else if (size == sizeof(u.d)) u.d = (double)n;
else u.n = n;
/* move 'u' to final result, correcting endianness if needed */
copywithendian(buff, u.buff, size, h.islittle);
luaL_addsize(&b, size);
break;
}
case Kchar: { /* fixed-size string */
size_t len;
const char *s = luaL_checklstring(L, arg, &len);
luaL_argcheck(L, len <= (size_t)size, arg,
"string longer than given size");
luaL_addlstring(&b, s, len); /* add string */
while (len++ < (size_t)size) /* pad extra space */
luaL_addchar(&b, LUAL_PACKPADBYTE);
break;
}
case Kstring: { /* strings with length count */
size_t len;
const char *s = luaL_checklstring(L, arg, &len);
luaL_argcheck(L, size >= (int)sizeof(size_t) ||
len < ((size_t)1 << (size * NB)),
arg, "string length does not fit in given size");
packint(&b, (lua_Unsigned)len, h.islittle, size, 0); /* pack length */
luaL_addlstring(&b, s, len);
totalsize += len;
break;
}
case Kzstr: { /* zero-terminated string */
size_t len;
const char *s = luaL_checklstring(L, arg, &len);
luaL_argcheck(L, strlen(s) == len, arg, "string contains zeros");
luaL_addlstring(&b, s, len);
luaL_addchar(&b, '\0'); /* add zero at the end */
totalsize += len + 1;
break;
}
case Kpadding: luaL_addchar(&b, LUAL_PACKPADBYTE); /* FALLTHROUGH */
case Kpaddalign: case Knop:
arg--; /* undo increment */
break;
}
}
luaL_pushresult(&b);
return 1;
}
