lstrlib.c

Bug Summary

File:	deps/lua/src/lstrlib.c
Warning:	line 322, column 43 Dereference of null pointer (loaded from variable 's')
Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name lstrlib.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mthread-model posix -mframe-pointer=none -fmath-errno -fno-rounding-math -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -dwarf-column-info -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -D LUA_ANSI -D ENABLE_CJSON_GLOBAL -D REDIS_STATIC= -D LUA_USE_MKSTEMP -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir /home/netto/Desktop/redis-6.2.1/deps/lua/src -ferror-limit 19 -fmessage-length 0 -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -faddrsig -o /tmp/scan-build-2021-03-14-133648-8817-1 -x c lstrlib.c
1/*
2** $Id: lstrlib.c,v 1.132.1.5 2010/05/14 15:34:19 roberto Exp $
3** Standard library for string operations and pattern-matching
4** See Copyright Notice in lua.h
5*/


8#include <ctype.h>
9#include <stddef.h>
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>

14#define lstrlib_c
15#define LUA_LIB

17#include "lua.h"

19#include "lauxlib.h"
20#include "lualib.h"


23/* macro to `unsign' a character */
24#define uchar(c)((unsigned char)(c))        ((unsigned char)(c))



28static int str_len (lua_State *L) {
size_t l;
luaL_checklstring(L, 1, &l);
lua_pushinteger(L, l);
return 1;
33}


36static ptrdiff_t posrelat (ptrdiff_t pos, size_t len) {
/* relative string position: negative means back from end */
if (pos < 0) pos += (ptrdiff_t)len + 1;
return (pos >= 0) ? pos : 0;
40}


43static int str_sub (lua_State *L) {
size_t l;
const char *s = luaL_checklstring(L, 1, &l);
ptrdiff_t start = posrelat(luaL_checkinteger(L, 2), l);
ptrdiff_t end = posrelat(luaL_optinteger(L, 3, -1), l);
if (start < 1) start = 1;
if (end > (ptrdiff_t)l) end = (ptrdiff_t)l;
if (start <= end)
  lua_pushlstring(L, s+start-1, end-start+1);
else lua_pushliteral(L, "")lua_pushlstring(L, "" "", (sizeof("")/sizeof(char))-1);
return 1;
54}


57static int str_reverse (lua_State *L) {
size_t l;
luaL_Buffer b;
const char *s = luaL_checklstring(L, 1, &l);
luaL_buffinit(L, &b);
while (l--) luaL_addchar(&b, s[l])((void)((&b)->p < ((&b)->buffer+8192) || luaL_prepbuffer
(&b)), (*(&b)->p++ = (char)(s[l])));
luaL_pushresult(&b);
return 1;
65}


68static int str_lower (lua_State *L) {
size_t l;
size_t i;
luaL_Buffer b;
const char *s = luaL_checklstring(L, 1, &l);
luaL_buffinit(L, &b);
for (i=0; i<l; i++)
  luaL_addchar(&b, tolower(uchar(s[i])))((void)((&b)->p < ((&b)->buffer+8192) || luaL_prepbuffer
(&b)), (*(&b)->p++ = (char)((__extension__ ({ int __res
; if (sizeof (((unsigned char)(s[i]))) > 1) { if (__builtin_constant_p
 (((unsigned char)(s[i])))) { int __c = (((unsigned char)(s[i
]))); __res = __c < -128 || __c > 255 ? __c : (*__ctype_tolower_loc
 ())[__c]; } else __res = tolower (((unsigned char)(s[i]))); }
 else __res = (*__ctype_tolower_loc ())[(int) (((unsigned char
)(s[i])))]; __res; })))));
luaL_pushresult(&b);
return 1;
78}


81static int str_upper (lua_State *L) {
size_t l;
size_t i;
luaL_Buffer b;
const char *s = luaL_checklstring(L, 1, &l);
luaL_buffinit(L, &b);
for (i=0; i<l; i++)
  luaL_addchar(&b, toupper(uchar(s[i])))((void)((&b)->p < ((&b)->buffer+8192) || luaL_prepbuffer
(&b)), (*(&b)->p++ = (char)((__extension__ ({ int __res
; if (sizeof (((unsigned char)(s[i]))) > 1) { if (__builtin_constant_p
 (((unsigned char)(s[i])))) { int __c = (((unsigned char)(s[i
]))); __res = __c < -128 || __c > 255 ? __c : (*__ctype_toupper_loc
 ())[__c]; } else __res = toupper (((unsigned char)(s[i]))); }
 else __res = (*__ctype_toupper_loc ())[(int) (((unsigned char
)(s[i])))]; __res; })))));
luaL_pushresult(&b);
return 1;
91}

93static int str_rep (lua_State *L) {
size_t l;
luaL_Buffer b;
const char *s = luaL_checklstring(L, 1, &l);
int n = luaL_checkint(L, 2)((int)luaL_checkinteger(L, (2)));
luaL_buffinit(L, &b);
while (n-- > 0)
  luaL_addlstring(&b, s, l);
luaL_pushresult(&b);
return 1;
103}


106static int str_byte (lua_State *L) {
size_t l;
const char *s = luaL_checklstring(L, 1, &l);
ptrdiff_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
ptrdiff_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
int n, i;
if (posi <= 0) posi = 1;
if ((size_t)pose > l) pose = 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])((unsigned char)(s[posi+i-1])));
return n;
122}


125static int str_char (lua_State *L) {
int n = lua_gettop(L);  /* number of arguments */
int i;
luaL_Buffer b;
luaL_buffinit(L, &b);
for (i=1; i<=n; i++) {
  int c = luaL_checkint(L, i)((int)luaL_checkinteger(L, (i)));
  luaL_argcheck(L, uchar(c) == c, i, "invalid value")((void)((((unsigned char)(c)) == c) || luaL_argerror(L, (i), (
"invalid value"))));
  luaL_addchar(&b, uchar(c))((void)((&b)->p < ((&b)->buffer+8192) || luaL_prepbuffer
(&b)), (*(&b)->p++ = (char)(((unsigned char)(c))))
);
}
luaL_pushresult(&b);
return 1;
137}


140static int writer (lua_State *L, const void* b, size_t size, void* B) {
(void)L;
luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
return 0;
144}


147static int str_dump (lua_State *L) {
luaL_Buffer b;
luaL_checktype(L, 1, LUA_TFUNCTION6);
lua_settop(L, 1);
luaL_buffinit(L,&b);
if (lua_dump(L, writer, &b) != 0)
  luaL_error(L, "unable to dump given function");
luaL_pushresult(&b);
return 1;
156}



160/*
161** {======================================================
162** PATTERN MATCHING
163** =======================================================
164*/


167#define CAP_UNFINISHED(-1)	(-1)
168#define CAP_POSITION(-2)	(-2)

170typedef struct MatchState {
const char *src_init;  /* init of source string */
const char *src_end;  /* end (`\0') of source string */
lua_State *L;
int level;  /* total number of captures (finished or unfinished) */
struct {
  const char *init;
  ptrdiff_t len;
} capture[LUA_MAXCAPTURES32];
179} MatchState;


182#define L_ESC'%'		'%'
183#define SPECIALS"^$*+?.([%-"	"^$*+?.([%-"


186static int check_capture (MatchState *ms, int l) {
l -= '1';
if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED(-1))
  return luaL_error(ms->L, "invalid capture index");
return l;
191}


194static int capture_to_close (MatchState *ms) {
int level = ms->level;
for (level--; level>=0; level--)
  if (ms->capture[level].len == CAP_UNFINISHED(-1)) return level;
return luaL_error(ms->L, "invalid pattern capture");
199}


202static const char *classend (MatchState *ms, const char *p) {
switch (*p++) {
  case L_ESC'%': {
    if (*p == '\0')
      luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%")"'" "%%" "'" ")");
    return p+1;
  }
  case '[': {
    if (*p == '^') p++;
    do {  /* look for a `]' */
      if (*p == '\0')
        luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]")"'" "]" "'" ")");
      if (*(p++) == L_ESC'%' && *p != '\0')
        p++;  /* skip escapes (e.g. `%]') */
    } while (*p != ']');
    return p+1;
  }
  default: {
    return p;
  }
}
223}


226static int match_class (int c, int cl) {
int res;
switch (tolower(cl)(__extension__ ({ int __res; if (sizeof (cl) > 1) { if (__builtin_constant_p
 (cl)) { int __c = (cl); __res = __c < -128 || __c > 255
 ? __c : (*__ctype_tolower_loc ())[__c]; } else __res = tolower
 (cl); } else __res = (*__ctype_tolower_loc ())[(int) (cl)]; __res
; }))) {
  case 'a' : res = isalpha(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISalpha
); break;
  case 'c' : res = iscntrl(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _IScntrl
); break;
  case 'd' : res = isdigit(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISdigit
); break;
  case 'l' : res = islower(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISlower
); break;
  case 'p' : res = ispunct(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISpunct
); break;
  case 's' : res = isspace(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISspace
); break;
  case 'u' : res = isupper(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISupper
); break;
  case 'w' : res = isalnum(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISalnum
); break;
  case 'x' : res = isxdigit(c)((*__ctype_b_loc ())[(int) ((c))] & (unsigned short int) _ISxdigit
); break;
  case 'z' : res = (c == 0); break;
  default: return (cl == c);
}
return (islower(cl)((*__ctype_b_loc ())[(int) ((cl))] & (unsigned short int)
 _ISlower) ? res : !res);
242}


245static 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)((unsigned char)(*p))))
      return sig;
  }
  else if ((*(p+1) == '-') && (p+2 < ec)) {
    p+=2;
    if (uchar(*(p-2))((unsigned char)(*(p-2))) <= c && c <= uchar(*p)((unsigned char)(*p)))
      return sig;
  }
  else if (uchar(*p)((unsigned char)(*p)) == c) return sig;
}
return !sig;
265}


268static int singlematch (int c, const char *p, const char *ep) {
switch (*p) {
  case '.': return 1;  /* matches any char */
  case L_ESC'%': return match_class(c, uchar(*(p+1))((unsigned char)(*(p+1))));
  case '[': return matchbracketclass(c, p, ep-1);
  default:  return (uchar(*p)((unsigned char)(*p)) == c);
}
275}


278static const char *match (MatchState *ms, const char *s, const char *p);


281static const char *matchbalance (MatchState *ms, const char *s,
                                 const char *p) {
if (*p == 0 || *(p+1) == 0)
  luaL_error(ms->L, "unbalanced pattern");
if (*s != *p) return NULL((void*)0);
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((void*)0);  /* string ends out of balance */
298}


301static 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 ((s+i)<ms->src_end && singlematch(uchar(*(s+i))((unsigned char)(*(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((void*)0);
313}


316static const char *min_expand (MatchState *ms, const char *s,
                               const char *p, const char *ep) {
for (;;) {
14
←
Loop condition is true.  Entering loop body→
  const char *res = match(ms, s, ep+1);
  if (res != NULL((void*)0))
15
←
Assuming 'res' is equal to NULL→
16
←
Taking false branch→
    return res;
  else if (s16.1
's' is < field 'src_end'
<ms->src_end && singlematch(uchar(*s)((unsigned char)(*s)), p, ep))
17
←
Dereference of null pointer (loaded from variable 's')
    s++;  /* try with one more repetition */
  else return NULL((void*)0);
}
326}


329static const char *start_capture (MatchState *ms, const char *s,
                                  const char *p, int what) {
const char *res;
int level = ms->level;
if (level >= LUA_MAXCAPTURES32) 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((void*)0))  /* match failed? */
  ms->level--;  /* undo capture */
return res;
340}


343static 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((void*)0))  /* match failed? */
  ms->capture[l].len = CAP_UNFINISHED(-1);  /* undo capture */
return res;
351}


354static 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((void*)0);
362}


365static const char *match (MatchState *ms, const char *s, const char *p) {
init: /* using goto's to optimize tail recursion */
switch (*p) {
9
←
Control jumps to the 'default' case at line 414→
  case '(': {  /* start capture */
    if (*(p+1) == ')')  /* position capture? */
      return start_capture(ms, s, p+2, CAP_POSITION(-2));
    else
      return start_capture(ms, s, p+1, CAP_UNFINISHED(-1));
  }
  case ')': {  /* end capture */
    return end_capture(ms, s, p+1);
  }
  case L_ESC'%': {
    switch (*(p+1)) {
      case 'b': {  /* balanced string? */
        s = matchbalance(ms, s, p+2);
        if (s == NULL((void*)0)) return NULL((void*)0);
        p+=4; goto init;  /* else return match(ms, s, p+4); */
      }
      case 'f': {  /* frontier? */
        const char *ep; char previous;
        p += 2;
        if (*p != '[')
          luaL_error(ms->L, "missing " LUA_QL("[")"'" "[" "'" " after "
                             LUA_QL("%%f")"'" "%%f" "'" " in pattern");
        ep = classend(ms, p);  /* points to what is next */
        previous = (s == ms->src_init) ? '\0' : *(s-1);
        if (matchbracketclass(uchar(previous)((unsigned char)(previous)), p, ep-1) ||
           !matchbracketclass(uchar(*s)((unsigned char)(*s)), p, ep-1)) return NULL((void*)0);
        p=ep; goto init;  /* else return match(ms, s, ep); */
      }
      default: {
        if (isdigit(uchar(*(p+1)))((*__ctype_b_loc ())[(int) ((((unsigned char)(*(p+1)))))] &
 (unsigned short int) _ISdigit)) {  /* capture results (%0-%9)? */
          s = match_capture(ms, s, uchar(*(p+1))((unsigned char)(*(p+1))));
          if (s == NULL((void*)0)) return NULL((void*)0);
          p+=2; goto init;  /* else return match(ms, s, p+2) */
        }
        goto dflt;  /* case default */
      }
    }
  }
  case '\0': {  /* end of pattern */
    return s;  /* match succeeded */
  }
  case '$': {
    if (*(p+1) == '\0')  /* is the `$' the last char in pattern? */
      return (s == ms->src_end) ? s : NULL((void*)0);  /* check end of string */
    else goto dflt;
  }
  default: dflt: {  /* it is a pattern item */
    const char *ep = classend(ms, p);  /* points to what is next */
    int m = s<ms->src_end && singlematch(uchar(*s)((unsigned char)(*s)), p, ep);
10
←
Assuming 's' is >= field 'src_end'→
    switch (*ep) {
11
←
Control jumps to 'case 45:'  at line 430→
      case '?': {  /* optional */
        const char *res;
        if (m && ((res=match(ms, s+1, ep+1)) != NULL((void*)0)))
          return res;
        p=ep+1; goto init;  /* else return match(ms, s, ep+1); */
      }
      case '*': {  /* 0 or more repetitions */
        return max_expand(ms, s, p, ep);
      }
      case '+': {  /* 1 or more repetitions */
        return (m ? max_expand(ms, s+1, p, ep) : NULL((void*)0));
      }
      case '-': {  /* 0 or more repetitions (minimum) */
        return min_expand(ms, s, p, ep);
12
←
Passing value via 2nd parameter 's'→
13
←
Calling 'min_expand'→
      }
      default: {
        if (!m) return NULL((void*)0);
        s++; p=ep; goto init;  /* else return match(ms, s+1, ep); */
      }
    }
  }
}
440}



444static 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((void*)0);  /* 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((void*)0)) {
    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((void*)0);  /* not found */
}
463}


466static 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(-1)) luaL_error(ms->L, "unfinished capture");
  if (l == CAP_POSITION(-2))
    lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
  else
    lua_pushlstring(ms->L, ms->capture[i].init, l);
}
482}


485static 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 */
492}


495static int str_find_aux (lua_State *L, int find) {
size_t l1, l2;
const char *s = luaL_checklstring(L, 1, &l1);
const char *p = luaL_checklstring(L, 2, &l2);
ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;
if (init < 0) init = 0;
else if ((size_t)(init) > l1) init = (ptrdiff_t)l1;
if (find && (lua_toboolean(L, 4) ||  /* explicit request? */
    strpbrk(p, SPECIALS"^$*+?.([%-") == NULL((void*)0))) {  /* or no special characters? */
  /* do a plain search */
  const char *s2 = lmemfind(s+init, l1-init, p, l2);
  if (s2) {
    lua_pushinteger(L, s2-s+1);
    lua_pushinteger(L, s2-s+l2);
    return 2;
  }
}
else {
  MatchState ms;
  int anchor = (*p == '^') ? (p++, 1) : 0;
  const char *s1=s+init;
  ms.L = L;
  ms.src_init = s;
  ms.src_end = s+l1;
  do {
    const char *res;
    ms.level = 0;
    if ((res=match(&ms, s1, p)) != NULL((void*)0)) {
      if (find) {
        lua_pushinteger(L, s1-s+1);  /* start */
        lua_pushinteger(L, res-s);   /* end */
        return push_captures(&ms, NULL((void*)0), 0) + 2;
      }
      else
        return push_captures(&ms, s1, res);
    }
  } while (s1++ < ms.src_end && !anchor);
}
lua_pushnil(L);  /* not found */
return 1;
535}


538static int str_find (lua_State *L) {
return str_find_aux(L, 1);
540}


543static int str_match (lua_State *L) {
return str_find_aux(L, 0);
545}


548static int gmatch_aux (lua_State *L) {
MatchState ms;
size_t ls;
const char *s = lua_tolstring(L, lua_upvalueindex(1)((-10002)-(1)), &ls);
const char *p = lua_tostring(L, lua_upvalueindex(2))lua_tolstring(L, (((-10002)-(2))), ((void*)0));
const char *src;
ms.L = L;
ms.src_init = s;
ms.src_end = s+ls;
for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3)((-10002)-(3)));
     src <= ms.src_end;
     src++) {
  const char *e;
  ms.level = 0;
  if ((e = match(&ms, src, p)) != NULL((void*)0)) {
    lua_Integer newstart = e-s;
    if (e == src) newstart++;  /* empty match? go at least one position */
    lua_pushinteger(L, newstart);
    lua_replace(L, lua_upvalueindex(3)((-10002)-(3)));
    return push_captures(&ms, src, e);
  }
}
return 0;  /* not found */
571}


574static int gmatch (lua_State *L) {
luaL_checkstring(L, 1)(luaL_checklstring(L, (1), ((void*)0)));
luaL_checkstring(L, 2)(luaL_checklstring(L, (2), ((void*)0)));
lua_settop(L, 2);
lua_pushinteger(L, 0);
lua_pushcclosure(L, gmatch_aux, 3);
return 1;
581}


584static int gfind_nodef (lua_State *L) {
return luaL_error(L, LUA_QL("string.gfind")"'" "string.gfind" "'" " was renamed to "
                     LUA_QL("string.gmatch")"'" "string.gmatch" "'");
587}


590static 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);
for (i = 0; i < l; i++) {
  if (news[i] != L_ESC'%')
    luaL_addchar(b, news[i])((void)((b)->p < ((b)->buffer+8192) || luaL_prepbuffer
(b)), (*(b)->p++ = (char)(news[i])));
  else {
    i++;  /* skip ESC */
    if (!isdigit(uchar(news[i]))((*__ctype_b_loc ())[(int) ((((unsigned char)(news[i]))))] &
 (unsigned short int) _ISdigit))
      luaL_addchar(b, news[i])((void)((b)->p < ((b)->buffer+8192) || luaL_prepbuffer
(b)), (*(b)->p++ = (char)(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 */
    }
  }
}
609}


612static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
                                                     const char *e) {
lua_State *L = ms->L;
switch (lua_type(L, 3)) {
  case LUA_TNUMBER3:
  case LUA_TSTRING4: {
    add_s(ms, b, s, e);
    return;
  }
  case LUA_TFUNCTION6: {
    int n;
    lua_pushvalue(L, 3);
    n = push_captures(ms, s, e);
    lua_call(L, n, 1);
    break;
  }
  case LUA_TTABLE5: {
    push_onecapture(ms, 0, s, e);
    lua_gettable(L, 3);
    break;
  }
}
if (!lua_toboolean(L, -1)) {  /* nil or false? */
  lua_pop(L, 1)lua_settop(L, -(1)-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)lua_typename(L, lua_type(L,(-1)))); 
luaL_addvalue(b);  /* add result to accumulator */
641}


644static int str_gsub (lua_State *L) {
size_t srcl;
const char *src = luaL_checklstring(L, 1, &srcl);
1
'src' initialized here→
const char *p = luaL_checkstring(L, 2)(luaL_checklstring(L, (2), ((void*)0)));
int  tr = lua_type(L, 3);
int max_s = luaL_optint(L, 4, srcl+1)((int)luaL_optinteger(L, (4), (srcl+1)));
int anchor = (*p == '^') ? (p++, 1) : 0;
2
←
Assuming the condition is false→
3
←
'?' condition is false→
int n = 0;
MatchState ms;
luaL_Buffer b;
luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||((void)((tr == 3 || tr == 4 || tr == 6 || tr == 5) || luaL_argerror
(L, (3), ("string/function/table expected"))))
4
←
Assuming 'tr' is equal to 3→
                 tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,((void)((tr == 3 || tr == 4 || tr == 6 || tr == 5) || luaL_argerror
(L, (3), ("string/function/table expected"))))
                    "string/function/table expected")((void)((tr == 3 || tr == 4 || tr == 6 || tr == 5) || luaL_argerror
(L, (3), ("string/function/table expected"))));
luaL_buffinit(L, &b);
ms.L = L;
ms.src_init = src;
ms.src_end = src+srcl;
while (n < max_s) {
5
←
Assuming 'n' is < 'max_s'→
6
←
Loop condition is true.  Entering loop body→
  const char *e;
  ms.level = 0;
  e = match(&ms, src, p);
7
←
Passing value via 2nd parameter 's'→
8
←
Calling 'match'→
  if (e) {
    n++;
    add_value(&ms, &b, src, e);
  }
  if (e && e>src) /* non empty match? */
    src = e;  /* skip it */
  else if (src < ms.src_end)
    luaL_addchar(&b, *src++)((void)((&b)->p < ((&b)->buffer+8192) || luaL_prepbuffer
(&b)), (*(&b)->p++ = (char)(*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;
680}

682/* }====================================================== */


685/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
686#define MAX_ITEM512	512
687/* valid flags in a format specification */
688#define FLAGS"-+ #0"	"-+ #0"
689/*
690** maximum size of each format specification (such as '%-099.99d')
691** (+10 accounts for %99.99x plus margin of error)
692*/
693#define MAX_FORMAT(sizeof("-+ #0") + sizeof("l") + 10)	(sizeof(FLAGS"-+ #0") + sizeof(LUA_INTFRMLEN"l") + 10)


696static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
size_t l;
const char *s = luaL_checklstring(L, arg, &l);
luaL_addchar(b, '"')((void)((b)->p < ((b)->buffer+8192) || luaL_prepbuffer
(b)), (*(b)->p++ = (char)('"')));
while (l--) {
  switch (*s) {
    case '"': case '\\': case '\n': {
      luaL_addchar(b, '\\')((void)((b)->p < ((b)->buffer+8192) || luaL_prepbuffer
(b)), (*(b)->p++ = (char)('\\')));
      luaL_addchar(b, *s)((void)((b)->p < ((b)->buffer+8192) || luaL_prepbuffer
(b)), (*(b)->p++ = (char)(*s)));
      break;
    }
    case '\r': {
      luaL_addlstring(b, "\\r", 2);
      break;
    }
    case '\0': {
      luaL_addlstring(b, "\\000", 4);
      break;
    }
    default: {
      luaL_addchar(b, *s)((void)((b)->p < ((b)->buffer+8192) || luaL_prepbuffer
(b)), (*(b)->p++ = (char)(*s)));
      break;
    }
  }
  s++;
}
luaL_addchar(b, '"')((void)((b)->p < ((b)->buffer+8192) || luaL_prepbuffer
(b)), (*(b)->p++ = (char)('"')));
723}

725static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
const char *p = strfrmt;
while (*p != '\0' && strchr(FLAGS"-+ #0", *p) != NULL((void*)0)) p++;  /* skip flags */
if ((size_t)(p - strfrmt) >= sizeof(FLAGS"-+ #0"))
  luaL_error(L, "invalid format (repeated flags)");
if (isdigit(uchar(*p))((*__ctype_b_loc ())[(int) ((((unsigned char)(*p))))] & (
unsigned short int) _ISdigit)) p++;  /* skip width */
if (isdigit(uchar(*p))((*__ctype_b_loc ())[(int) ((((unsigned char)(*p))))] & (
unsigned short int) _ISdigit)) p++;  /* (2 digits at most) */
if (*p == '.') {
  p++;
  if (isdigit(uchar(*p))((*__ctype_b_loc ())[(int) ((((unsigned char)(*p))))] & (
unsigned short int) _ISdigit)) p++;  /* skip precision */
  if (isdigit(uchar(*p))((*__ctype_b_loc ())[(int) ((((unsigned char)(*p))))] & (
unsigned short int) _ISdigit)) p++;  /* (2 digits at most) */
}
if (isdigit(uchar(*p))((*__ctype_b_loc ())[(int) ((((unsigned char)(*p))))] & (
unsigned short int) _ISdigit))
  luaL_error(L, "invalid format (width or precision too long)");
*(form++) = '%';
strncpy(form, strfrmt, p - strfrmt + 1);
form += p - strfrmt + 1;
*form = '\0';
return p;
744}


747static void addintlen (char *form) {
size_t l = strlen(form);
char spec = form[l - 1];
strcpy(form + l - 1, LUA_INTFRMLEN"l");
form[l + sizeof(LUA_INTFRMLEN"l") - 2] = spec;
form[l + sizeof(LUA_INTFRMLEN"l") - 1] = '\0';
753}


756static 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++)((void)((&b)->p < ((&b)->buffer+8192) || luaL_prepbuffer
(&b)), (*(&b)->p++ = (char)(*strfrmt++)));
  else if (*++strfrmt == L_ESC'%')
    luaL_addchar(&b, *strfrmt++)((void)((&b)->p < ((&b)->buffer+8192) || luaL_prepbuffer
(&b)), (*(&b)->p++ = (char)(*strfrmt++)));  /* %% */
  else { /* format item */
    char form[MAX_FORMAT(sizeof("-+ #0") + sizeof("l") + 10)];  /* to store the format (`%...') */
    char buff[MAX_ITEM512];  /* to store the formatted item */
    if (++arg > top)
      luaL_argerror(L, arg, "no value");
    strfrmt = scanformat(L, strfrmt, form);
    switch (*strfrmt++) {
      case 'c': {
        sprintf(buff, form, (int)luaL_checknumber(L, arg));
        break;
      }
      case 'd':  case 'i': {
        addintlen(form);
        sprintf(buff, form, (LUA_INTFRM_Tlong)luaL_checknumber(L, arg));
        break;
      }
      case 'o':  case 'u':  case 'x':  case 'X': {
        addintlen(form);
        sprintf(buff, form, (unsigned LUA_INTFRM_Tlong)luaL_checknumber(L, arg));
        break;
      }
      case 'e':  case 'E': case 'f':
      case 'g': case 'G': {
        sprintf(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 {
          sprintf(buff, form, s);
          break;
        }
      }
      default: {  /* also treat cases `pnLlh' */
        return luaL_error(L, "invalid option " LUA_QL("%%%c")"'" "%%%c" "'" " to "
                             LUA_QL("format")"'" "format" "'", *(strfrmt - 1));
      }
    }
    luaL_addlstring(&b, buff, strlen(buff));
  }
}
luaL_pushresult(&b);
return 1;
824}


827static const luaL_Reg strlib[] = {
{"byte", str_byte},
{"char", str_char},
{"dump", str_dump},
{"find", str_find},
{"format", str_format},
{"gfind", gfind_nodef},
{"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},
{NULL((void*)0), NULL((void*)0)}
844};


847static void createmetatable (lua_State *L) {
lua_createtable(L, 0, 1);  /* create metatable for strings */
lua_pushliteral(L, "")lua_pushlstring(L, "" "", (sizeof("")/sizeof(char))-1);  /* dummy string */
lua_pushvalue(L, -2);
lua_setmetatable(L, -2);  /* set string metatable */
lua_pop(L, 1)lua_settop(L, -(1)-1);  /* pop dummy string */
lua_pushvalue(L, -2);  /* string library... */
lua_setfield(L, -2, "__index");  /* ...is the __index metamethod */
lua_pop(L, 1)lua_settop(L, -(1)-1);  /* pop metatable */
856}


859/*
860** Open string library
861*/
862LUALIB_APIextern int luaopen_string (lua_State *L) {
luaL_register(L, LUA_STRLIBNAME"string", strlib);
864#if defined(LUA_COMPAT_GFIND)
lua_getfield(L, -1, "gmatch");
lua_setfield(L, -2, "gfind");
867#endif
createmetatable(L);
return 1;
870}
