luau/VM/src/lstrlib.cpp
2022-08-04 07:22:16 -07:00

1676 lines
46 KiB
C++

// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
// This code is based on Lua 5.x implementation licensed under MIT License; see lua_LICENSE.txt for details
#include "lualib.h"
#include "lstring.h"
#include <ctype.h>
#include <string.h>
#include <stdio.h>
LUAU_FASTFLAGVARIABLE(LuauTostringFormatSpecifier, false);
/* macro to `unsign' a character */
#define uchar(c) ((unsigned char)(c))
static int str_len(lua_State* L)
{
size_t l;
luaL_checklstring(L, 1, &l);
lua_pushinteger(L, (int)l);
return 1;
}
static int posrelat(int pos, size_t len)
{
/* relative string position: negative means back from end */
if (pos < 0)
pos += (int)len + 1;
return (pos >= 0) ? pos : 0;
}
static int str_sub(lua_State* L)
{
size_t l;
const char* s = luaL_checklstring(L, 1, &l);
int start = posrelat(luaL_checkinteger(L, 2), l);
int end = posrelat(luaL_optinteger(L, 3, -1), l);
if (start < 1)
start = 1;
if (end > (int)l)
end = (int)l;
if (start <= end)
lua_pushlstring(L, s + start - 1, end - start + 1);
else
lua_pushliteral(L, "");
return 1;
}
static int str_reverse(lua_State* L)
{
size_t l;
const char* s = luaL_checklstring(L, 1, &l);
luaL_Buffer b;
char* ptr = luaL_buffinitsize(L, &b, l);
while (l--)
*ptr++ = s[l];
luaL_pushresultsize(&b, ptr - b.p);
return 1;
}
static int str_lower(lua_State* L)
{
size_t l;
const char* s = luaL_checklstring(L, 1, &l);
luaL_Buffer b;
char* ptr = luaL_buffinitsize(L, &b, l);
for (size_t i = 0; i < l; i++)
*ptr++ = tolower(uchar(s[i]));
luaL_pushresultsize(&b, l);
return 1;
}
static int str_upper(lua_State* L)
{
size_t l;
const char* s = luaL_checklstring(L, 1, &l);
luaL_Buffer b;
char* ptr = luaL_buffinitsize(L, &b, l);
for (size_t i = 0; i < l; i++)
*ptr++ = toupper(uchar(s[i]));
luaL_pushresultsize(&b, l);
return 1;
}
static int str_rep(lua_State* L)
{
size_t l;
const char* s = luaL_checklstring(L, 1, &l);
int n = luaL_checkinteger(L, 2);
if (n <= 0)
{
lua_pushliteral(L, "");
return 1;
}
if (l > MAXSSIZE / (size_t)n) // may overflow?
luaL_error(L, "resulting string too large");
luaL_Buffer b;
char* ptr = luaL_buffinitsize(L, &b, l * n);
const char* start = ptr;
size_t left = l * n;
size_t step = l;
memcpy(ptr, s, l);
ptr += l;
left -= l;
// use the increasing 'pattern' inside our target buffer to fill the next part
while (step < left)
{
memcpy(ptr, start, step);
ptr += step;
left -= step;
step <<= 1;
}
// fill tail
memcpy(ptr, start, left);
ptr += left;
luaL_pushresultsize(&b, l * n);
return 1;
}
static int str_byte(lua_State* L)
{
size_t l;
const char* s = luaL_checklstring(L, 1, &l);
int posi = posrelat(luaL_optinteger(L, 2, 1), l);
int pose = posrelat(luaL_optinteger(L, 3, posi), l);
int n, i;
if (posi <= 0)
posi = 1;
if ((size_t)pose > l)
pose = (int)l;
if (posi > pose)
return 0; /* empty interval; return no values */
n = (int)(pose - posi + 1);
if (posi + n <= pose) /* overflow? */
luaL_error(L, "string slice too long");
luaL_checkstack(L, n, "string slice too long");
for (i = 0; i < n; i++)
lua_pushinteger(L, uchar(s[posi + i - 1]));
return n;
}
static int str_char(lua_State* L)
{
int n = lua_gettop(L); /* number of arguments */
luaL_Buffer b;
char* ptr = luaL_buffinitsize(L, &b, n);
for (int i = 1; i <= n; i++)
{
int c = luaL_checkinteger(L, i);
luaL_argcheck(L, uchar(c) == c, i, "invalid value");
*ptr++ = uchar(c);
}
luaL_pushresultsize(&b, n);
return 1;
}
/*
** {======================================================
** PATTERN MATCHING
** =======================================================
*/
#define CAP_UNFINISHED (-1)
#define CAP_POSITION (-2)
typedef struct MatchState
{
int matchdepth; /* control for recursive depth (to avoid C stack overflow) */
const char* src_init; /* init of source string */
const char* src_end; /* end ('\0') of source string */
const char* p_end; /* end ('\0') of pattern */
lua_State* L;
int level; /* total number of captures (finished or unfinished) */
struct
{
const char* init;
ptrdiff_t len;
} capture[LUA_MAXCAPTURES];
} MatchState;
/* recursive function */
static const char* match(MatchState* ms, const char* s, const char* p);
#define L_ESC '%'
#define SPECIALS "^$*+?.([%-"
static int check_capture(MatchState* ms, int l)
{
l -= '1';
if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
luaL_error(ms->L, "invalid capture index %%%d", l + 1);
return l;
}
static int capture_to_close(MatchState* ms)
{
int level = ms->level;
for (level--; level >= 0; level--)
if (ms->capture[level].len == CAP_UNFINISHED)
return level;
luaL_error(ms->L, "invalid pattern capture");
}
static const char* classend(MatchState* ms, const char* p)
{
switch (*p++)
{
case L_ESC:
{
if (p == ms->p_end)
luaL_error(ms->L, "malformed pattern (ends with '%%')");
return p + 1;
}
case '[':
{
if (*p == '^')
p++;
do
{ /* look for a `]' */
if (p == ms->p_end)
luaL_error(ms->L, "malformed pattern (missing ']')");
if (*(p++) == L_ESC && p < ms->p_end)
p++; /* skip escapes (e.g. `%]') */
} while (*p != ']');
return p + 1;
}
default:
{
return p;
}
}
}
static int match_class(int c, int cl)
{
int res;
switch (tolower(cl))
{
case 'a':
res = isalpha(c);
break;
case 'c':
res = iscntrl(c);
break;
case 'd':
res = isdigit(c);
break;
case 'g':
res = isgraph(c);
break;
case 'l':
res = islower(c);
break;
case 'p':
res = ispunct(c);
break;
case 's':
res = isspace(c);
break;
case 'u':
res = isupper(c);
break;
case 'w':
res = isalnum(c);
break;
case 'x':
res = isxdigit(c);
break;
case 'z':
res = (c == 0);
break; /* deprecated option */
default:
return (cl == c);
}
return (islower(cl) ? res : !res);
}
static int matchbracketclass(int c, const char* p, const char* ec)
{
int sig = 1;
if (*(p + 1) == '^')
{
sig = 0;
p++; /* skip the `^' */
}
while (++p < ec)
{
if (*p == L_ESC)
{
p++;
if (match_class(c, uchar(*p)))
return sig;
}
else if ((*(p + 1) == '-') && (p + 2 < ec))
{
p += 2;
if (uchar(*(p - 2)) <= c && c <= uchar(*p))
return sig;
}
else if (uchar(*p) == c)
return sig;
}
return !sig;
}
static int singlematch(MatchState* ms, const char* s, const char* p, const char* ep)
{
if (s >= ms->src_end)
return 0;
else
{
int c = uchar(*s);
switch (*p)
{
case '.':
return 1; /* matches any char */
case L_ESC:
return match_class(c, uchar(*(p + 1)));
case '[':
return matchbracketclass(c, p, ep - 1);
default:
return (uchar(*p) == c);
}
}
}
static const char* matchbalance(MatchState* ms, const char* s, const char* p)
{
if (p >= ms->p_end - 1)
luaL_error(ms->L, "malformed pattern (missing arguments to '%%b')");
if (*s != *p)
return NULL;
else
{
int b = *p;
int e = *(p + 1);
int cont = 1;
while (++s < ms->src_end)
{
if (*s == e)
{
if (--cont == 0)
return s + 1;
}
else if (*s == b)
cont++;
}
}
return NULL; /* string ends out of balance */
}
static const char* max_expand(MatchState* ms, const char* s, const char* p, const char* ep)
{
ptrdiff_t i = 0; /* counts maximum expand for item */
while (singlematch(ms, s + i, p, ep))
i++;
/* keeps trying to match with the maximum repetitions */
while (i >= 0)
{
const char* res = match(ms, (s + i), ep + 1);
if (res)
return res;
i--; /* else didn't match; reduce 1 repetition to try again */
}
return NULL;
}
static const char* min_expand(MatchState* ms, const char* s, const char* p, const char* ep)
{
for (;;)
{
const char* res = match(ms, s, ep + 1);
if (res != NULL)
return res;
else if (singlematch(ms, s, p, ep))
s++; /* try with one more repetition */
else
return NULL;
}
}
static const char* start_capture(MatchState* ms, const char* s, const char* p, int what)
{
const char* res;
int level = ms->level;
if (level >= LUA_MAXCAPTURES)
luaL_error(ms->L, "too many captures");
ms->capture[level].init = s;
ms->capture[level].len = what;
ms->level = level + 1;
if ((res = match(ms, s, p)) == NULL) /* match failed? */
ms->level--; /* undo capture */
return res;
}
static const char* end_capture(MatchState* ms, const char* s, const char* p)
{
int l = capture_to_close(ms);
const char* res;
ms->capture[l].len = s - ms->capture[l].init; /* close capture */
if ((res = match(ms, s, p)) == NULL) /* match failed? */
ms->capture[l].len = CAP_UNFINISHED; /* undo capture */
return res;
}
static const char* match_capture(MatchState* ms, const char* s, int l)
{
size_t len;
l = check_capture(ms, l);
len = ms->capture[l].len;
if ((size_t)(ms->src_end - s) >= len && memcmp(ms->capture[l].init, s, len) == 0)
return s + len;
else
return NULL;
}
static const char* match(MatchState* ms, const char* s, const char* p)
{
if (ms->matchdepth-- == 0)
luaL_error(ms->L, "pattern too complex");
init: /* using goto's to optimize tail recursion */
if (p != ms->p_end)
{ /* end of pattern? */
switch (*p)
{
case '(':
{ /* start capture */
if (*(p + 1) == ')') /* position capture? */
s = start_capture(ms, s, p + 2, CAP_POSITION);
else
s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
break;
}
case ')':
{ /* end capture */
s = end_capture(ms, s, p + 1);
break;
}
case '$':
{
if ((p + 1) != ms->p_end) /* is the `$' the last char in pattern? */
goto dflt; /* no; go to default */
s = (s == ms->src_end) ? s : NULL; /* check end of string */
break;
}
case L_ESC:
{ /* escaped sequences not in the format class[*+?-]? */
switch (*(p + 1))
{
case 'b':
{ /* balanced string? */
s = matchbalance(ms, s, p + 2);
if (s != NULL)
{
p += 4;
goto init; /* return match(ms, s, p + 4); */
} /* else fail (s == NULL) */
break;
}
case 'f':
{ /* frontier? */
const char* ep;
char previous;
p += 2;
if (*p != '[')
luaL_error(ms->L, "missing '[' after '%%f' in pattern");
ep = classend(ms, p); /* points to what is next */
previous = (s == ms->src_init) ? '\0' : *(s - 1);
if (!matchbracketclass(uchar(previous), p, ep - 1) && matchbracketclass(uchar(*s), p, ep - 1))
{
p = ep;
goto init; /* return match(ms, s, ep); */
}
s = NULL; /* match failed */
break;
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
{ /* capture results (%0-%9)? */
s = match_capture(ms, s, uchar(*(p + 1)));
if (s != NULL)
{
p += 2;
goto init; /* return match(ms, s, p + 2) */
}
break;
}
default:
goto dflt;
}
break;
}
default:
dflt:
{ /* pattern class plus optional suffix */
const char* ep = classend(ms, p); /* points to optional suffix */
/* does not match at least once? */
if (!singlematch(ms, s, p, ep))
{
if (*ep == '*' || *ep == '?' || *ep == '-')
{ /* accept empty? */
p = ep + 1;
goto init; /* return match(ms, s, ep + 1); */
}
else /* '+' or no suffix */
s = NULL; /* fail */
}
else
{ /* matched once */
switch (*ep)
{ /* handle optional suffix */
case '?':
{ /* optional */
const char* res;
if ((res = match(ms, s + 1, ep + 1)) != NULL)
s = res;
else
{
p = ep + 1;
goto init; /* else return match(ms, s, ep + 1); */
}
break;
}
case '+': /* 1 or more repetitions */
s++; /* 1 match already done */
/* go through */
case '*': /* 0 or more repetitions */
s = max_expand(ms, s, p, ep);
break;
case '-': /* 0 or more repetitions (minimum) */
s = min_expand(ms, s, p, ep);
break;
default: /* no suffix */
s++;
p = ep;
goto init; /* return match(ms, s + 1, ep); */
}
}
break;
}
}
}
ms->matchdepth++;
return s;
}
static const char* lmemfind(const char* s1, size_t l1, const char* s2, size_t l2)
{
if (l2 == 0)
return s1; /* empty strings are everywhere */
else if (l2 > l1)
return NULL; /* avoids a negative `l1' */
else
{
const char* init; /* to search for a `*s2' inside `s1' */
l2--; /* 1st char will be checked by `memchr' */
l1 = l1 - l2; /* `s2' cannot be found after that */
while (l1 > 0 && (init = (const char*)memchr(s1, *s2, l1)) != NULL)
{
init++; /* 1st char is already checked */
if (memcmp(init, s2 + 1, l2) == 0)
return init - 1;
else
{ /* correct `l1' and `s1' to try again */
l1 -= init - s1;
s1 = init;
}
}
return NULL; /* not found */
}
}
static void push_onecapture(MatchState* ms, int i, const char* s, const char* e)
{
if (i >= ms->level)
{
if (i == 0) /* ms->level == 0, too */
lua_pushlstring(ms->L, s, e - s); /* add whole match */
else
luaL_error(ms->L, "invalid capture index");
}
else
{
ptrdiff_t l = ms->capture[i].len;
if (l == CAP_UNFINISHED)
luaL_error(ms->L, "unfinished capture");
if (l == CAP_POSITION)
lua_pushinteger(ms->L, (int)(ms->capture[i].init - ms->src_init) + 1);
else
lua_pushlstring(ms->L, ms->capture[i].init, l);
}
}
static int push_captures(MatchState* ms, const char* s, const char* e)
{
int i;
int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
luaL_checkstack(ms->L, nlevels, "too many captures");
for (i = 0; i < nlevels; i++)
push_onecapture(ms, i, s, e);
return nlevels; /* number of strings pushed */
}
/* check whether pattern has no special characters */
static int nospecials(const char* p, size_t l)
{
size_t upto = 0;
do
{
if (strpbrk(p + upto, SPECIALS))
return 0; /* pattern has a special character */
upto += strlen(p + upto) + 1; /* may have more after \0 */
} while (upto <= l);
return 1; /* no special chars found */
}
static void prepstate(MatchState* ms, lua_State* L, const char* s, size_t ls, const char* p, size_t lp)
{
ms->L = L;
ms->matchdepth = LUAI_MAXCCALLS;
ms->src_init = s;
ms->src_end = s + ls;
ms->p_end = p + lp;
}
static void reprepstate(MatchState* ms)
{
ms->level = 0;
LUAU_ASSERT(ms->matchdepth == LUAI_MAXCCALLS);
}
static int str_find_aux(lua_State* L, int find)
{
size_t ls, lp;
const char* s = luaL_checklstring(L, 1, &ls);
const char* p = luaL_checklstring(L, 2, &lp);
int init = posrelat(luaL_optinteger(L, 3, 1), ls);
if (init < 1)
init = 1;
else if (init > (int)ls + 1)
{ /* start after string's end? */
lua_pushnil(L); /* cannot find anything */
return 1;
}
/* explicit request or no special characters? */
if (find && (lua_toboolean(L, 4) || nospecials(p, lp)))
{
/* do a plain search */
const char* s2 = lmemfind(s + init - 1, ls - init + 1, p, lp);
if (s2)
{
lua_pushinteger(L, (int)(s2 - s + 1));
lua_pushinteger(L, (int)(s2 - s + lp));
return 2;
}
}
else
{
MatchState ms;
const char* s1 = s + init - 1;
int anchor = (*p == '^');
if (anchor)
{
p++;
lp--; /* skip anchor character */
}
prepstate(&ms, L, s, ls, p, lp);
do
{
const char* res;
reprepstate(&ms);
if ((res = match(&ms, s1, p)) != NULL)
{
if (find)
{
lua_pushinteger(L, (int)(s1 - s + 1)); /* start */
lua_pushinteger(L, (int)(res - s)); /* end */
return push_captures(&ms, NULL, 0) + 2;
}
else
return push_captures(&ms, s1, res);
}
} while (s1++ < ms.src_end && !anchor);
}
lua_pushnil(L); /* not found */
return 1;
}
static int str_find(lua_State* L)
{
return str_find_aux(L, 1);
}
static int str_match(lua_State* L)
{
return str_find_aux(L, 0);
}
static int gmatch_aux(lua_State* L)
{
MatchState ms;
size_t ls, lp;
const char* s = lua_tolstring(L, lua_upvalueindex(1), &ls);
const char* p = lua_tolstring(L, lua_upvalueindex(2), &lp);
const char* src;
prepstate(&ms, L, s, ls, p, lp);
for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3)); src <= ms.src_end; src++)
{
const char* e;
reprepstate(&ms);
if ((e = match(&ms, src, p)) != NULL)
{
int newstart = (int)(e - s);
if (e == src)
newstart++; /* empty match? go at least one position */
lua_pushinteger(L, newstart);
lua_replace(L, lua_upvalueindex(3));
return push_captures(&ms, src, e);
}
}
return 0; /* not found */
}
static int gmatch(lua_State* L)
{
luaL_checkstring(L, 1);
luaL_checkstring(L, 2);
lua_settop(L, 2);
lua_pushinteger(L, 0);
lua_pushcclosure(L, gmatch_aux, NULL, 3);
return 1;
}
static void add_s(MatchState* ms, luaL_Buffer* b, const char* s, const char* e)
{
size_t l, i;
const char* news = lua_tolstring(ms->L, 3, &l);
luaL_reservebuffer(b, l, -1);
for (i = 0; i < l; i++)
{
if (news[i] != L_ESC)
luaL_addchar(b, news[i]);
else
{
i++; /* skip ESC */
if (!isdigit(uchar(news[i])))
{
if (news[i] != L_ESC)
luaL_error(ms->L, "invalid use of '%c' in replacement string", L_ESC);
luaL_addchar(b, news[i]);
}
else if (news[i] == '0')
luaL_addlstring(b, s, e - s);
else
{
push_onecapture(ms, news[i] - '1', s, e);
luaL_addvalue(b); /* add capture to accumulated result */
}
}
}
}
static void add_value(MatchState* ms, luaL_Buffer* b, const char* s, const char* e, int tr)
{
lua_State* L = ms->L;
switch (tr)
{
case LUA_TFUNCTION:
{
int n;
lua_pushvalue(L, 3);
n = push_captures(ms, s, e);
lua_call(L, n, 1);
break;
}
case LUA_TTABLE:
{
push_onecapture(ms, 0, s, e);
lua_gettable(L, 3);
break;
}
default:
{ /* LUA_TNUMBER or LUA_TSTRING */
add_s(ms, b, s, e);
return;
}
}
if (!lua_toboolean(L, -1))
{ /* nil or false? */
lua_pop(L, 1);
lua_pushlstring(L, s, e - s); /* keep original text */
}
else if (!lua_isstring(L, -1))
luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
luaL_addvalue(b); /* add result to accumulator */
}
static int str_gsub(lua_State* L)
{
size_t srcl, lp;
const char* src = luaL_checklstring(L, 1, &srcl);
const char* p = luaL_checklstring(L, 2, &lp);
int tr = lua_type(L, 3);
int max_s = luaL_optinteger(L, 4, (int)srcl + 1);
int anchor = (*p == '^');
int n = 0;
MatchState ms;
luaL_Buffer b;
luaL_argexpected(L, tr == LUA_TNUMBER || tr == LUA_TSTRING || tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3, "string/function/table");
luaL_buffinit(L, &b);
if (anchor)
{
p++;
lp--; /* skip anchor character */
}
prepstate(&ms, L, src, srcl, p, lp);
while (n < max_s)
{
const char* e;
reprepstate(&ms);
e = match(&ms, src, p);
if (e)
{
n++;
add_value(&ms, &b, src, e, tr);
}
if (e && e > src) /* non empty match? */
src = e; /* skip it */
else if (src < ms.src_end)
luaL_addchar(&b, *src++);
else
break;
if (anchor)
break;
}
luaL_addlstring(&b, src, ms.src_end - src);
luaL_pushresult(&b);
lua_pushinteger(L, n); /* number of substitutions */
return 2;
}
/* }====================================================== */
/* valid flags in a format specification */
#define FLAGS "-+ #0"
/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
#define MAX_ITEM 512
/* maximum size of each format specification (such as '%-099.99d') */
#define MAX_FORMAT 32
static void addquoted(lua_State* L, luaL_Buffer* b, int arg)
{
size_t l;
const char* s = luaL_checklstring(L, arg, &l);
luaL_reservebuffer(b, l + 2, -1);
luaL_addchar(b, '"');
while (l--)
{
switch (*s)
{
case '"':
case '\\':
case '\n':
{
luaL_addchar(b, '\\');
luaL_addchar(b, *s);
break;
}
case '\r':
{
luaL_addlstring(b, "\\r", 2);
break;
}
case '\0':
{
luaL_addlstring(b, "\\000", 4);
break;
}
default:
{
luaL_addchar(b, *s);
break;
}
}
s++;
}
luaL_addchar(b, '"');
}
static const char* scanformat(lua_State* L, const char* strfrmt, char* form, size_t* size)
{
const char* p = strfrmt;
while (*p != '\0' && strchr(FLAGS, *p) != NULL)
p++; /* skip flags */
if ((size_t)(p - strfrmt) >= sizeof(FLAGS))
luaL_error(L, "invalid format (repeated flags)");
if (isdigit(uchar(*p)))
p++; /* skip width */
if (isdigit(uchar(*p)))
p++; /* (2 digits at most) */
if (*p == '.')
{
p++;
if (isdigit(uchar(*p)))
p++; /* skip precision */
if (isdigit(uchar(*p)))
p++; /* (2 digits at most) */
}
if (isdigit(uchar(*p)))
luaL_error(L, "invalid format (width or precision too long)");
*(form++) = '%';
*size = p - strfrmt + 1;
strncpy(form, strfrmt, *size);
form += *size;
*form = '\0';
return p;
}
static void addInt64Format(char form[MAX_FORMAT], char formatIndicator, size_t formatItemSize)
{
LUAU_ASSERT((formatItemSize + 3) <= MAX_FORMAT);
LUAU_ASSERT(form[0] == '%');
LUAU_ASSERT(form[formatItemSize] != 0);
LUAU_ASSERT(form[formatItemSize + 1] == 0);
form[formatItemSize + 0] = 'l';
form[formatItemSize + 1] = 'l';
form[formatItemSize + 2] = formatIndicator;
form[formatItemSize + 3] = 0;
}
static int str_format(lua_State* L)
{
int top = lua_gettop(L);
int arg = 1;
size_t sfl;
const char* strfrmt = luaL_checklstring(L, arg, &sfl);
const char* strfrmt_end = strfrmt + sfl;
luaL_Buffer b;
luaL_buffinit(L, &b);
while (strfrmt < strfrmt_end)
{
if (*strfrmt != L_ESC)
luaL_addchar(&b, *strfrmt++);
else if (*++strfrmt == L_ESC)
luaL_addchar(&b, *strfrmt++); /* %% */
else
{ /* format item */
char form[MAX_FORMAT]; /* to store the format (`%...') */
char buff[MAX_ITEM]; /* to store the formatted item */
if (++arg > top)
luaL_error(L, "missing argument #%d", arg);
size_t formatItemSize = 0;
strfrmt = scanformat(L, strfrmt, form, &formatItemSize);
char formatIndicator = *strfrmt++;
switch (formatIndicator)
{
case 'c':
{
snprintf(buff, sizeof(buff), form, (int)luaL_checknumber(L, arg));
break;
}
case 'd':
case 'i':
{
addInt64Format(form, formatIndicator, formatItemSize);
snprintf(buff, sizeof(buff), form, (long long)luaL_checknumber(L, arg));
break;
}
case 'o':
case 'u':
case 'x':
case 'X':
{
double argValue = luaL_checknumber(L, arg);
addInt64Format(form, formatIndicator, formatItemSize);
unsigned long long v = (argValue < 0) ? (unsigned long long)(long long)argValue : (unsigned long long)argValue;
snprintf(buff, sizeof(buff), form, v);
break;
}
case 'e':
case 'E':
case 'f':
case 'g':
case 'G':
{
snprintf(buff, sizeof(buff), form, (double)luaL_checknumber(L, arg));
break;
}
case 'q':
{
addquoted(L, &b, arg);
continue; /* skip the 'addsize' at the end */
}
case 's':
{
size_t l;
const char* s = luaL_checklstring(L, arg, &l);
if (!strchr(form, '.') && l >= 100)
{
/* no precision and string is too long to be formatted;
keep original string */
lua_pushvalue(L, arg);
luaL_addvalue(&b);
continue; /* skip the `addsize' at the end */
}
else
{
snprintf(buff, sizeof(buff), form, s);
break;
}
}
case '*':
{
if (!FFlag::LuauTostringFormatSpecifier)
{
luaL_error(L, "invalid option '%%*' to 'format'");
break;
}
if (formatItemSize != 1)
{
luaL_error(L, "'%%*' does not take a form");
}
size_t length;
const char* string = luaL_tolstring(L, arg, &length);
luaL_addlstring(&b, string, length);
continue; /* skip the `addsize' at the end */
}
default:
{ /* also treat cases `pnLlh' */
luaL_error(L, "invalid option '%%%c' to 'format'", *(strfrmt - 1));
}
}
luaL_addlstring(&b, buff, strlen(buff));
}
}
luaL_pushresult(&b);
return 1;
}
static int str_split(lua_State* L)
{
size_t haystackLen;
const char* haystack = luaL_checklstring(L, 1, &haystackLen);
size_t needleLen;
const char* needle = luaL_optlstring(L, 2, ",", &needleLen);
const char* begin = haystack;
const char* end = haystack + haystackLen;
const char* spanStart = begin;
int numMatches = 0;
lua_createtable(L, 0, 0);
if (needleLen == 0)
begin++;
// Don't iterate the last needleLen - 1 bytes of the string - they are
// impossible to be splits and would let us memcmp past the end of the
// buffer.
for (const char* iter = begin; iter <= end - needleLen; iter++)
{
// Use of memcmp here instead of strncmp is so that we allow embedded
// nulls to be used in either of the haystack or the needle strings.
// Most Lua string APIs allow embedded nulls, and this should be no
// exception.
if (memcmp(iter, needle, needleLen) == 0)
{
lua_pushinteger(L, ++numMatches);
lua_pushlstring(L, spanStart, iter - spanStart);
lua_settable(L, -3);
spanStart = iter + needleLen;
if (needleLen > 0)
iter += needleLen - 1;
}
}
if (needleLen > 0)
{
lua_pushinteger(L, ++numMatches);
lua_pushlstring(L, spanStart, end - spanStart);
lua_settable(L, -3);
}
return 1;
}
/*
** {======================================================
** PACK/UNPACK
** =======================================================
*/
/* value used for padding */
#if !defined(LUAL_PACKPADBYTE)
#define LUAL_PACKPADBYTE 0x00
#endif
/* maximum size for the binary representation of an integer */
#define MAXINTSIZE 16
/* number of bits in a character */
#define NB CHAR_BIT
/* mask for one character (NB 1's) */
#define MC ((1 << NB) - 1)
/* internal size of integers used for pack/unpack */
#define SZINT (int)sizeof(long long)
/* dummy union to get native endianness */
static const union
{
int dummy;
char little; /* true iff machine is little endian */
} nativeendian = {1};
/* assume we need to align for double & pointers */
#define MAXALIGN 8
/*
** Union for serializing floats
*/
typedef union Ftypes
{
float f;
double d;
double n;
char buff[5 * sizeof(double)]; /* enough for any float type */
} Ftypes;
/*
** information to pack/unpack stuff
*/
typedef struct Header
{
lua_State* L;
int islittle;
int maxalign;
} Header;
/*
** options for pack/unpack
*/
typedef enum KOption
{
Kint, /* signed integers */
Kuint, /* unsigned integers */
Kfloat, /* floating-point numbers */
Kchar, /* fixed-length strings */
Kstring, /* strings with prefixed length */
Kzstr, /* zero-terminated strings */
Kpadding, /* padding */
Kpaddalign, /* padding for alignment */
Knop /* no-op (configuration or spaces) */
} KOption;
/*
** Read an integer numeral from string 'fmt' or return 'df' if
** there is no numeral
*/
static int digit(int c)
{
return '0' <= c && c <= '9';
}
static int getnum(Header* h, const char** fmt, int df)
{
if (!digit(**fmt)) /* no number? */
return df; /* return default value */
else
{
int a = 0;
do
{
a = a * 10 + (*((*fmt)++) - '0');
} while (digit(**fmt) && a <= (INT_MAX - 9) / 10);
if (a > MAXSSIZE || digit(**fmt))
luaL_error(h->L, "size specifier is too large");
return a;
}
}
/*
** Read an integer numeral and raises an error if it is larger
** than the maximum size for integers.
*/
static int getnumlimit(Header* h, const char** fmt, int df)
{
int sz = getnum(h, fmt, df);
if (sz > MAXINTSIZE || sz <= 0)
luaL_error(h->L, "integral size (%d) out of limits [1,%d]", sz, MAXINTSIZE);
return sz;
}
/*
** Initialize Header
*/
static void initheader(lua_State* L, Header* h)
{
h->L = L;
h->islittle = nativeendian.little;
h->maxalign = 1;
}
/*
** Read and classify next option. 'size' is filled with option's size.
*/
static KOption getoption(Header* h, const char** fmt, int* size)
{
int opt = *((*fmt)++);
*size = 0; /* default */
switch (opt)
{
case 'b':
*size = 1;
return Kint;
case 'B':
*size = 1;
return Kuint;
case 'h':
*size = 2;
return Kint;
case 'H':
*size = 2;
return Kuint;
case 'l':
*size = 8;
return Kint;
case 'L':
*size = 8;
return Kuint;
case 'j':
*size = 4;
return Kint;
case 'J':
*size = 4;
return Kuint;
case 'T':
*size = 4;
return Kuint;
case 'f':
*size = 4;
return Kfloat;
case 'd':
*size = 8;
return Kfloat;
case 'n':
*size = 8;
return Kfloat;
case 'i':
*size = getnumlimit(h, fmt, 4);
return Kint;
case 'I':
*size = getnumlimit(h, fmt, 4);
return Kuint;
case 's':
*size = getnumlimit(h, fmt, 4);
return Kstring;
case 'c':
*size = getnum(h, fmt, -1);
if (*size == -1)
luaL_error(h->L, "missing size for format option 'c'");
return Kchar;
case 'z':
return Kzstr;
case 'x':
*size = 1;
return Kpadding;
case 'X':
return Kpaddalign;
case ' ':
break;
case '<':
h->islittle = 1;
break;
case '>':
h->islittle = 0;
break;
case '=':
h->islittle = nativeendian.little;
break;
case '!':
h->maxalign = getnumlimit(h, fmt, MAXALIGN);
break;
default:
luaL_error(h->L, "invalid format option '%c'", opt);
}
return Knop;
}
/*
** Read, classify, and fill other details about the next option.
** 'psize' is filled with option's size, 'notoalign' with its
** alignment requirements.
** Local variable 'size' gets the size to be aligned. (Kpadal option
** always gets its full alignment, other options are limited by
** the maximum alignment ('maxalign'). Kchar option needs no alignment
** despite its size.
*/
static KOption getdetails(Header* h, size_t totalsize, const char** fmt, int* psize, int* ntoalign)
{
KOption opt = getoption(h, fmt, psize);
int align = *psize; /* usually, alignment follows size */
if (opt == Kpaddalign)
{ /* 'X' gets alignment from following option */
if (**fmt == '\0' || getoption(h, fmt, &align) == Kchar || align == 0)
luaL_argerror(h->L, 1, "invalid next option for option 'X'");
}
if (align <= 1 || opt == Kchar) /* need no alignment? */
*ntoalign = 0;
else
{
if (align > h->maxalign) /* enforce maximum alignment */
align = h->maxalign;
if ((align & (align - 1)) != 0) /* is 'align' not a power of 2? */
luaL_argerror(h->L, 1, "format asks for alignment not power of 2");
*ntoalign = (align - (int)(totalsize & (align - 1))) & (align - 1);
}
return opt;
}
/*
** Pack integer 'n' with 'size' bytes and 'islittle' endianness.
** The final 'if' handles the case when 'size' is larger than
** the size of a Lua integer, correcting the extra sign-extension
** bytes if necessary (by default they would be zeros).
*/
static void packint(luaL_Buffer* b, unsigned long long n, int islittle, int size, int neg)
{
LUAU_ASSERT(size <= MAXINTSIZE);
char buff[MAXINTSIZE];
int i;
buff[islittle ? 0 : size - 1] = (char)(n & MC); /* first byte */
for (i = 1; i < size; i++)
{
n >>= NB;
buff[islittle ? i : size - 1 - i] = (char)(n & MC);
}
if (neg && size > SZINT)
{ /* negative number need sign extension? */
for (i = SZINT; i < size; i++) /* correct extra bytes */
buff[islittle ? i : size - 1 - i] = (char)MC;
}
luaL_addlstring(b, buff, size); /* add result to buffer */
}
/*
** Copy 'size' bytes from 'src' to 'dest', correcting endianness if
** given 'islittle' is different from native endianness.
*/
static void copywithendian(volatile char* dest, volatile const char* src, int size, int islittle)
{
if (islittle == nativeendian.little)
{
while (size-- != 0)
*(dest++) = *(src++);
}
else
{
dest += size - 1;
while (size-- != 0)
*(dest--) = *(src++);
}
}
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 */
long long n = (long long)luaL_checknumber(L, arg);
if (size < SZINT)
{ /* need overflow check? */
long long lim = (long long)1 << ((size * NB) - 1);
luaL_argcheck(L, -lim <= n && n < lim, arg, "integer overflow");
}
packint(&b, n, h.islittle, size, (n < 0));
break;
}
case Kuint:
{ /* unsigned integers */
long long n = (long long)luaL_checknumber(L, arg);
if (size < SZINT) /* need overflow check? */
luaL_argcheck(L, (unsigned long long)n < ((unsigned long long)1 << (size * NB)), arg, "unsigned overflow");
packint(&b, (unsigned long long)n, h.islittle, size, 0);
break;
}
case Kfloat:
{ /* floating-point options */
volatile Ftypes u;
char buff[MAXINTSIZE];
double 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_addlstring(&b, buff, 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, 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;
}
static int str_packsize(lua_State* L)
{
Header h;
const char* fmt = luaL_checkstring(L, 1); /* format string */
int 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 <= MAXSSIZE - size, 1, "format result too large");
totalsize += size;
}
lua_pushinteger(L, totalsize);
return 1;
}
/*
** Unpack an integer with 'size' bytes and 'islittle' endianness.
** If size is smaller than the size of a Lua integer and integer
** is signed, must do sign extension (propagating the sign to the
** higher bits); if size is larger than the size of a Lua integer,
** it must check the unread bytes to see whether they do not cause an
** overflow.
*/
static long long unpackint(lua_State* L, const char* str, int islittle, int size, int issigned)
{
unsigned long long res = 0;
int i;
int limit = (size <= SZINT) ? size : SZINT;
for (i = limit - 1; i >= 0; i--)
{
res <<= NB;
res |= (unsigned char)str[islittle ? i : size - 1 - i];
}
if (size < SZINT)
{ /* real size smaller than int? */
if (issigned)
{ /* needs sign extension? */
unsigned long long mask = (unsigned long long)1 << (size * NB - 1);
res = ((res ^ mask) - mask); /* do sign extension */
}
}
else if (size > SZINT)
{ /* must check unread bytes */
int mask = (!issigned || (long long)res >= 0) ? 0 : MC;
for (i = limit; i < size; i++)
{
if ((unsigned char)str[islittle ? i : size - 1 - i] != mask)
luaL_error(L, "%d-byte integer does not fit into Lua Integer", size);
}
}
return (long long)res;
}
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);
int pos = posrelat(luaL_optinteger(L, 3, 1), ld) - 1;
if (pos < 0)
pos = 0;
int n = 0; /* number of results */
luaL_argcheck(L, size_t(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:
{
long long res = unpackint(L, data + pos, h.islittle, size, true);
lua_pushnumber(L, (double)res);
break;
}
case Kuint:
{
unsigned long long res = unpackint(L, data + pos, h.islittle, size, false);
lua_pushnumber(L, (double)res);
break;
}
case Kfloat:
{
volatile Ftypes u;
double num;
copywithendian(u.buff, data + pos, size, h.islittle);
if (size == sizeof(u.f))
num = (double)u.f;
else if (size == sizeof(u.d))
num = (double)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 += (int)len; /* skip string */
break;
}
case Kzstr:
{
size_t len = strlen(data + pos);
luaL_argcheck(L, pos + len < ld, 2, "unfinished string for format 'z'");
lua_pushlstring(L, data + pos, len);
pos += (int)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 const luaL_Reg strlib[] = {
{"byte", str_byte},
{"char", str_char},
{"find", str_find},
{"format", str_format},
{"gmatch", gmatch},
{"gsub", str_gsub},
{"len", str_len},
{"lower", str_lower},
{"match", str_match},
{"rep", str_rep},
{"reverse", str_reverse},
{"sub", str_sub},
{"upper", str_upper},
{"split", str_split},
{"pack", str_pack},
{"packsize", str_packsize},
{"unpack", str_unpack},
{NULL, NULL},
};
static void createmetatable(lua_State* L)
{
lua_createtable(L, 0, 1); /* create metatable for strings */
lua_pushliteral(L, ""); /* dummy string */
lua_pushvalue(L, -2);
lua_setmetatable(L, -2); /* set string metatable */
lua_pop(L, 1); /* pop dummy string */
lua_pushvalue(L, -2); /* string library... */
lua_setfield(L, -2, "__index"); /* ...is the __index metamethod */
lua_pop(L, 1); /* pop metatable */
}
/*
** Open string library
*/
int luaopen_string(lua_State* L)
{
luaL_register(L, LUA_STRLIBNAME, strlib);
createmetatable(L);
return 1;
}