diff options
author | Florian Westphal <fw@strlen.de> | 2021-03-08 18:18:33 +0100 |
---|---|---|
committer | Florian Westphal <fw@strlen.de> | 2021-03-11 13:43:30 +0100 |
commit | 5896772fe3c5f01696188ea04957a825ee601b12 (patch) | |
tree | 42c1971b34a17ea7107bbeb0b60c11d863dd05d1 /src/scanner.l | |
parent | f8d5fa7c0523d8058e11c823c4664c9ba9ccf121 (diff) |
scanner: introduce start condition stack
Add a small initial chunk of flex start conditionals.
This starts with two low-hanging fruits, numgen and j/symhash.
NUMGEN and HASH start conditions are entered from flex when
the corresponding expression token is encountered.
Flex returns to the INIT condition when the bison parser
has seen a complete numgen/hash statement.
This intentionally uses a stack rather than BEGIN()
to eventually support nested states.
The scanner_pop_start_cond() function argument is not used yet, but
will need to be used later to deal with nesting.
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'src/scanner.l')
-rw-r--r-- | src/scanner.l | 36 |
1 files changed, 29 insertions, 7 deletions
diff --git a/src/scanner.l b/src/scanner.l index 1da3b5e0..94225c29 100644 --- a/src/scanner.l +++ b/src/scanner.l @@ -98,6 +98,8 @@ static void reset_pos(struct parser_state *state, struct location *loc) state->indesc->column = 1; } +static void scanner_push_start_cond(void *scanner, enum startcond_type type); + #define YY_USER_ACTION { \ update_pos(yyget_extra(yyscanner), yylloc, yyleng); \ update_offset(yyget_extra(yyscanner), yylloc, yyleng); \ @@ -193,6 +195,9 @@ addrstring ({macaddr}|{ip4addr}|{ip6addr}) %option yylineno %option nodefault %option warn +%option stack +%s SCANSTATE_EXPR_HASH +%s SCANSTATE_EXPR_NUMGEN %% @@ -548,15 +553,21 @@ addrstring ({macaddr}|{ip4addr}|{ip6addr}) "state" { return STATE; } "status" { return STATUS; } -"numgen" { return NUMGEN; } -"inc" { return INC; } -"mod" { return MOD; } -"offset" { return OFFSET; } +"numgen" { scanner_push_start_cond(yyscanner, SCANSTATE_EXPR_NUMGEN); return NUMGEN; } +<SCANSTATE_EXPR_NUMGEN>{ + "inc" { return INC; } +} -"jhash" { return JHASH; } -"symhash" { return SYMHASH; } -"seed" { return SEED; } +"jhash" { scanner_push_start_cond(yyscanner, SCANSTATE_EXPR_HASH); return JHASH; } +"symhash" { scanner_push_start_cond(yyscanner, SCANSTATE_EXPR_HASH); return SYMHASH; } +<SCANSTATE_EXPR_HASH>{ + "seed" { return SEED; } +} +<SCANSTATE_EXPR_HASH,SCANSTATE_EXPR_NUMGEN>{ + "mod" { return MOD; } + "offset" { return OFFSET; } +} "dup" { return DUP; } "fwd" { return FWD; } @@ -967,3 +978,14 @@ void scanner_destroy(struct nft_ctx *nft) input_descriptor_list_destroy(state); yylex_destroy(nft->scanner); } + +static void scanner_push_start_cond(void *scanner, enum startcond_type type) +{ + yy_push_state((int)type, scanner); +} + +void scanner_pop_start_cond(void *scanner, enum startcond_type t) +{ + yy_pop_state(scanner); + (void)yy_top_state(scanner); /* suppress gcc warning wrt. unused function */ +} |