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bc: disallow invalid syntax like "{ print 1 print 2 }"

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statement parsing must NOT eat the terminator: caller needs to know
what it was, to correctly decide whether it is a valid one.

function                                             old     new   delta
zxc_program_read                                       -     234    +234
zdc_program_printStream                                -     144    +144
zbc_parse_stmt_possibly_auto                        1413    1460     +47
zxc_vm_process                                       869     859     -10
zxc_program_exec                                    4116    4101     -15
zdc_program_asciify                                  368       -    -368
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 1/2 up/down: 425/-393)           Total: 32 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2019-01-08 18:08:48 +01:00
parent ce51140664
commit fc7aa7a296
1 changed files with 21 additions and 15 deletions
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36
miscutils/bc.c
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@@ -4554,11 +4554,11 @@ static BC_STATUS zbc_parse_stmt_possibly_auto(bool auto_allowed)
if (p->lex == XC_LEX_NLINE) {
dbg_lex_done("%s:%d done (seen XC_LEX_NLINE)", __func__, __LINE__);
RETURN_STATUS(zxc_lex_next());
RETURN_STATUS(s);
}
if (p->lex == BC_LEX_SCOLON) {
dbg_lex_done("%s:%d done (seen BC_LEX_SCOLON)", __func__, __LINE__);
RETURN_STATUS(zxc_lex_next());
RETURN_STATUS(s);
}
if (p->lex == BC_LEX_LBRACE) {
@@ -4574,9 +4574,19 @@ static BC_STATUS zbc_parse_stmt_possibly_auto(bool auto_allowed)
}
while (p->lex != BC_LEX_RBRACE) {
dbg_lex("%s:%d block parsing loop", __func__, __LINE__);
//FIXME: prevent wrong syntax such as "{ print 1 print 2 }"
s = zbc_parse_stmt();
if (s) RETURN_STATUS(s);
// Check that next token is a correct stmt delimiter -
// disallows "print 1 print 2" and such.
if (p->lex == BC_LEX_RBRACE)
break;
if (p->lex != BC_LEX_SCOLON
&& p->lex != XC_LEX_NLINE
) {
RETURN_STATUS(bc_error_at("bad statement terminator"));
}
s = zxc_lex_next();
if (s) RETURN_STATUS(s);
}
s = zxc_lex_next();
dbg_lex_done("%s:%d done (seen BC_LEX_RBRACE)", __func__, __LINE__);
@@ -4665,9 +4675,11 @@ static BC_STATUS zbc_parse_stmt_or_funcdef(void)
BcStatus s;
dbg_lex_enter("%s:%d entered", __func__, __LINE__);
if (p->lex == XC_LEX_EOF)
s = bc_error("end of file");
else if (p->lex == BC_LEX_KEY_DEFINE) {
//why?
// if (p->lex == XC_LEX_EOF)
// s = bc_error("end of file");
// else
if (p->lex == BC_LEX_KEY_DEFINE) {
dbg_lex("%s:%d p->lex:BC_LEX_KEY_DEFINE", __func__, __LINE__);
s = zbc_parse_funcdef();
} else {
@@ -6781,7 +6793,6 @@ static BC_STATUS zxc_vm_process(const char *text)
s = zxc_parse_text_init(text); // does the first zxc_lex_next()
if (s) RETURN_STATUS(s);
IF_BC(check_eof:)
while (G.prs.lex != XC_LEX_EOF) {
BcInstPtr *ip;
BcFunc *f;
@@ -6789,14 +6800,6 @@ static BC_STATUS zxc_vm_process(const char *text)
dbg_lex("%s:%d G.prs.lex:%d, parsing...", __func__, __LINE__, G.prs.lex);
if (IS_BC) {
#if ENABLE_BC
if (G.prs.lex == BC_LEX_SCOLON
|| G.prs.lex == XC_LEX_NLINE
) {
s = zxc_lex_next();
if (s) goto err;
goto check_eof;
}
s = zbc_parse_stmt_or_funcdef();
if (s) goto err;
@@ -6855,6 +6858,9 @@ static BC_STATUS zxc_vm_process(const char *text)
#endif
IF_BC(bc_vec_pop_all(&f->strs);)
IF_BC(bc_vec_pop_all(&f->consts);)
// We are at SCOLON/NLINE, skip it:
s = zxc_lex_next();
if (s) goto err;
} else {
if (G.prog.results.len == 0
&& G.prog.vars.len == 0