/* Helper for CAT. Coercion, iterative concat, __concat metamethod. */ TValue *lj_meta_cat(lua_State *L, TValue *top, int left) { int fromc = 0; if (left < 0) { left = -left; fromc = 1; } do { if (!(tvisstr(top) || tvisnumber(top)) || !(tvisstr(top-1) || tvisnumber(top-1))) { cTValue *mo = lj_meta_lookup(L, top-1, MM_concat); if (tvisnil(mo)) { mo = lj_meta_lookup(L, top, MM_concat); if (tvisnil(mo)) { if (tvisstr(top-1) || tvisnumber(top-1)) top++; lj_err_optype(L, top-1, LJ_ERR_OPCAT); return NULL; /* unreachable */ } } /* One of the top two elements is not a string, call __cat metamethod: ** ** before: [...][CAT stack .........................] ** top-1 top top+1 top+2 ** pick two: [...][CAT stack ...] [o1] [o2] ** setup mm: [...][CAT stack ...] [cont|?] [mo|tmtype] [o1] [o2] ** in asm: [...][CAT stack ...] [cont|PC] [mo|delta] [o1] [o2] ** ^-- func base ^-- mm base ** after mm: [...][CAT stack ...] <--push-- [result] ** next step: [...][CAT stack .............] */ copyTV(L, top+2*LJ_FR2+2, top); /* Carefully ordered stack copies! */ copyTV(L, top+2*LJ_FR2+1, top-1); copyTV(L, top+LJ_FR2, mo); setcont(top-1, lj_cont_cat); if (LJ_FR2) { setnilV(top); setnilV(top+2); top += 2; } return top+1; /* Trigger metamethod call. */ } else { /* Pick as many strings as possible from the top and concatenate them: ** ** before: [...][CAT stack ...........................] ** pick str: [...][CAT stack ...] [...... strings ......] ** concat: [...][CAT stack ...] [result] ** next step: [...][CAT stack ............] */ TValue *e, *o = top; uint64_t tlen = tvisstr(o) ? strV(o)->len : STRFMT_MAXBUF_NUM; char *p, *buf; do { o--; tlen += tvisstr(o) ? strV(o)->len : STRFMT_MAXBUF_NUM; } while (--left > 0 && (tvisstr(o-1) || tvisnumber(o-1))); if (tlen >= LJ_MAX_STR) lj_err_msg(L, LJ_ERR_STROV); p = buf = lj_buf_tmp(L, (MSize)tlen); for (e = top, top = o; o <= e; o++) { if (tvisstr(o)) { GCstr *s = strV(o); MSize len = s->len; p = lj_buf_wmem(p, strdata(s), len); } else if (tvisint(o)) { p = lj_strfmt_wint(p, intV(o)); } else { lua_assert(tvisnum(o)); p = lj_strfmt_wnum(p, o); } } setstrV(L, top, lj_str_new(L, buf, (size_t)(p-buf))); } } while (left >= 1); if (LJ_UNLIKELY(G(L)->gc.total >= G(L)->gc.threshold)) { if (!fromc) L->top = curr_topL(L); lj_gc_step(L); } return NULL; }
/* Helper for CAT. Coercion, iterative concat, __concat metamethod. */ TValue *lj_meta_cat(lua_State *L, TValue *top, int left) { int fromc = 0; if (left < 0) { left = -left; fromc = 1; } do { int n = 1; if (!(tvisstr(top-1) || tvisnumber(top-1)) || !tostring(L, top)) { cTValue *mo = lj_meta_lookup(L, top-1, MM_concat); if (tvisnil(mo)) { mo = lj_meta_lookup(L, top, MM_concat); if (tvisnil(mo)) { if (tvisstr(top-1) || tvisnumber(top-1)) top++; lj_err_optype(L, top-1, LJ_ERR_OPCAT); return NULL; /* unreachable */ } } /* One of the top two elements is not a string, call __cat metamethod: ** ** before: [...][CAT stack .........................] ** top-1 top top+1 top+2 ** pick two: [...][CAT stack ...] [o1] [o2] ** setup mm: [...][CAT stack ...] [cont|?] [mo|tmtype] [o1] [o2] ** in asm: [...][CAT stack ...] [cont|PC] [mo|delta] [o1] [o2] ** ^-- func base ^-- mm base ** after mm: [...][CAT stack ...] <--push-- [result] ** next step: [...][CAT stack .............] */ copyTV(L, top+2, top); /* Careful with the order of stack copies! */ copyTV(L, top+1, top-1); copyTV(L, top, mo); setcont(top-1, lj_cont_cat); return top+1; /* Trigger metamethod call. */ } else if (strV(top)->len == 0) { /* Shortcut. */ (void)tostring(L, top-1); } else { /* Pick as many strings as possible from the top and concatenate them: ** ** before: [...][CAT stack ...........................] ** pick str: [...][CAT stack ...] [...... strings ......] ** concat: [...][CAT stack ...] [result] ** next step: [...][CAT stack ............] */ MSize tlen = strV(top)->len; char *buffer; int i; for (n = 1; n <= left && tostring(L, top-n); n++) { MSize len = strV(top-n)->len; if (len >= LJ_MAX_STR - tlen) lj_err_msg(L, LJ_ERR_STROV); tlen += len; } buffer = lj_str_needbuf(L, &G(L)->tmpbuf, tlen); n--; tlen = 0; for (i = n; i >= 0; i--) { MSize len = strV(top-i)->len; memcpy(buffer + tlen, strVdata(top-i), len); tlen += len; } setstrV(L, top-n, lj_str_new(L, buffer, tlen)); } left -= n; top -= n; } while (left >= 1); if (LJ_UNLIKELY(G(L)->gc.total >= G(L)->gc.threshold)) { if (!fromc) L->top = curr_topL(L); lj_gc_step(L); } return NULL; }