ref: 6ff5c10ffb06d10eee06f1d432f9cc4738496c07
dir: /sys/src/cmd/cpp/lex.c/
#include <u.h> #include <libc.h> #include <stdio.h> #include "cpp.h" /* * lexical FSM encoding * when in state state, and one of the characters * in ch arrives, enter nextstate. * States >= S_SELF are either final, or at least require special action. * In 'fsm' there is a line for each state X charset X nextstate. * List chars that overwrite previous entries later (e.g. C_ALPH * can be overridden by '_' by a later entry; and C_XX is the * the universal set, and should always be first. * States above S_SELF are represented in the big table as negative values. * S_SELF and S_SELFB encode the resulting token type in the upper bits. * These actions differ in that S_SELF doesn't have a lookahead char, * S_SELFB does. * * The encoding is blown out into a big table for time-efficiency. * Entries have * nextstate: 6 bits; ?\ marker: 1 bit; tokentype: 9 bits. */ #define MAXSTATE 32 #define ACT(tok,act) ((tok<<7)+act) #define QBSBIT 0100 #define GETACT(st) (st>>7)&0x1ff #define UTF2(c) ((c)>=0xA0 && (c)<0xE0) /* 2-char UTF seq */ #define UTF3(c) ((c)>=0xE0 && (c)<0xF0) /* 3-char UTF seq */ #define UTF4(c) ((c)>=0xF0 && (c)<0xF8) /* 4-char UTF seq */ /* character classes */ #define C_WS 1 #define C_ALPH 2 #define C_NUM 3 #define C_EOF 4 #define C_XX 5 enum state { START=0, NUM1, NUM2, NUM3, ID1, ST1, ST2, ST3, COM1, COM2, COM3, COM4, CC1, CC2, WS1, PLUS1, MINUS1, STAR1, SLASH1, PCT1, SHARP1, CIRC1, GT1, GT2, LT1, LT2, OR1, AND1, ASG1, NOT1, DOTS1, S_SELF=MAXSTATE, S_SELFB, S_EOF, S_NL, S_EOFSTR, S_STNL, S_COMNL, S_EOFCOM, S_COMMENT, S_WS, S_NAME }; int tottok; int tokkind[256]; struct fsm { int state; /* if in this state */ uchar ch[4]; /* and see one of these characters */ int nextstate; /* enter this state if +ve */ }; /*const*/ struct fsm fsm[] = { /* start state */ START, { C_XX }, ACT(UNCLASS,S_SELF), START, { ' ', '\t', '\v', '\r' }, WS1, START, { C_NUM }, NUM1, START, { '.' }, NUM3, START, { C_ALPH }, ID1, START, { 'L' }, ST1, START, { '"' }, ST2, START, { '\'' }, CC1, START, { '/' }, COM1, START, { EOFC }, S_EOF, START, { '\n' }, S_NL, START, { '-' }, MINUS1, START, { '+' }, PLUS1, START, { '<' }, LT1, START, { '>' }, GT1, START, { '=' }, ASG1, START, { '!' }, NOT1, START, { '&' }, AND1, START, { '|' }, OR1, START, { '#' }, SHARP1, START, { '%' }, PCT1, START, { '[' }, ACT(SBRA,S_SELF), START, { ']' }, ACT(SKET,S_SELF), START, { '(' }, ACT(LP,S_SELF), START, { ')' }, ACT(RP,S_SELF), START, { '*' }, STAR1, START, { ',' }, ACT(COMMA,S_SELF), START, { '?' }, ACT(QUEST,S_SELF), START, { ':' }, ACT(COLON,S_SELF), START, { ';' }, ACT(SEMIC,S_SELF), START, { '{' }, ACT(CBRA,S_SELF), START, { '}' }, ACT(CKET,S_SELF), START, { '~' }, ACT(TILDE,S_SELF), START, { '^' }, CIRC1, /* saw a digit */ NUM1, { C_XX }, ACT(NUMBER,S_SELFB), NUM1, { C_NUM, C_ALPH, '.' }, NUM1, NUM1, { 'E', 'e' }, NUM2, NUM1, { '_' }, ACT(NUMBER,S_SELFB), /* saw possible start of exponent, digits-e */ NUM2, { C_XX }, ACT(NUMBER,S_SELFB), NUM2, { '+', '-' }, NUM1, NUM2, { C_NUM, C_ALPH }, NUM1, NUM2, { '_' }, ACT(NUMBER,S_SELFB), /* saw a '.', which could be a number or an operator */ NUM3, { C_XX }, ACT(DOT,S_SELFB), NUM3, { '.' }, DOTS1, NUM3, { C_NUM }, NUM1, DOTS1, { C_XX }, ACT(UNCLASS, S_SELFB), DOTS1, { C_NUM }, NUM1, DOTS1, { '.' }, ACT(ELLIPS, S_SELF), /* saw a letter or _ */ ID1, { C_XX }, ACT(NAME,S_NAME), ID1, { C_ALPH, C_NUM }, ID1, /* saw L (start of wide string?) */ ST1, { C_XX }, ACT(NAME,S_NAME), ST1, { C_ALPH, C_NUM }, ID1, ST1, { '"' }, ST2, ST1, { '\'' }, CC1, /* saw " beginning string */ ST2, { C_XX }, ST2, ST2, { '"' }, ACT(STRING, S_SELF), ST2, { '\\' }, ST3, ST2, { '\n' }, S_STNL, ST2, { EOFC }, S_EOFSTR, /* saw \ in string */ ST3, { C_XX }, ST2, ST3, { '\n' }, S_STNL, ST3, { EOFC }, S_EOFSTR, /* saw ' beginning character const */ CC1, { C_XX }, CC1, CC1, { '\'' }, ACT(CCON, S_SELF), CC1, { '\\' }, CC2, CC1, { '\n' }, S_STNL, CC1, { EOFC }, S_EOFSTR, /* saw \ in ccon */ CC2, { C_XX }, CC1, CC2, { '\n' }, S_STNL, CC2, { EOFC }, S_EOFSTR, /* saw /, perhaps start of comment */ COM1, { C_XX }, ACT(SLASH, S_SELFB), COM1, { '=' }, ACT(ASSLASH, S_SELF), COM1, { '*' }, COM2, COM1, { '/' }, COM4, /* saw "/*", start of comment */ COM2, { C_XX }, COM2, COM2, { '\n' }, S_COMNL, COM2, { '*' }, COM3, COM2, { EOFC }, S_EOFCOM, /* saw the * possibly ending a comment */ COM3, { C_XX }, COM2, COM3, { '\n' }, S_COMNL, COM3, { '*' }, COM3, COM3, { '/' }, S_COMMENT, COM3, { EOFC }, S_EOFCOM, /* // comment */ COM4, { C_XX }, COM4, COM4, { '\n' }, S_NL, COM4, { EOFC }, S_EOFCOM, /* saw white space, eat it up */ WS1, { C_XX }, S_WS, WS1, { ' ', '\t', '\v', '\r'}, WS1, /* saw -, check --, -=, -> */ MINUS1, { C_XX }, ACT(MINUS, S_SELFB), MINUS1, { '-' }, ACT(MMINUS, S_SELF), MINUS1, { '=' }, ACT(ASMINUS,S_SELF), MINUS1, { '>' }, ACT(ARROW,S_SELF), /* saw +, check ++, += */ PLUS1, { C_XX }, ACT(PLUS, S_SELFB), PLUS1, { '+' }, ACT(PPLUS, S_SELF), PLUS1, { '=' }, ACT(ASPLUS, S_SELF), /* saw <, check <<, <<=, <= */ LT1, { C_XX }, ACT(LT, S_SELFB), LT1, { '<' }, LT2, LT1, { '=' }, ACT(LEQ, S_SELF), LT2, { C_XX }, ACT(LSH, S_SELFB), LT2, { '=' }, ACT(ASLSH, S_SELF), /* saw >, check >>, >>=, >= */ GT1, { C_XX }, ACT(GT, S_SELFB), GT1, { '>' }, GT2, GT1, { '=' }, ACT(GEQ, S_SELF), GT2, { C_XX }, ACT(RSH, S_SELFB), GT2, { '=' }, ACT(ASRSH, S_SELF), /* = */ ASG1, { C_XX }, ACT(ASGN, S_SELFB), ASG1, { '=' }, ACT(EQ, S_SELF), /* ! */ NOT1, { C_XX }, ACT(NOT, S_SELFB), NOT1, { '=' }, ACT(NEQ, S_SELF), /* & */ AND1, { C_XX }, ACT(AND, S_SELFB), AND1, { '&' }, ACT(LAND, S_SELF), AND1, { '=' }, ACT(ASAND, S_SELF), /* | */ OR1, { C_XX }, ACT(OR, S_SELFB), OR1, { '|' }, ACT(LOR, S_SELF), OR1, { '=' }, ACT(ASOR, S_SELF), /* # */ SHARP1, { C_XX }, ACT(SHARP, S_SELFB), SHARP1, { '#' }, ACT(DSHARP, S_SELF), /* % */ PCT1, { C_XX }, ACT(PCT, S_SELFB), PCT1, { '=' }, ACT(ASPCT, S_SELF), /* * */ STAR1, { C_XX }, ACT(STAR, S_SELFB), STAR1, { '=' }, ACT(ASSTAR, S_SELF), /* ^ */ CIRC1, { C_XX }, ACT(CIRC, S_SELFB), CIRC1, { '=' }, ACT(ASCIRC, S_SELF), -1 }; /* first index is char, second is state */ /* increase #states to power of 2 to encourage use of shift */ short bigfsm[256][MAXSTATE]; void expandlex(void) { /*const*/ struct fsm *fp; int i, j, nstate; for (fp = fsm; fp->state>=0; fp++) { for (i=0; fp->ch[i]; i++) { nstate = fp->nextstate; if (nstate >= S_SELF) nstate = ~nstate; switch (fp->ch[i]) { case C_XX: /* random characters */ for (j=0; j<256; j++) bigfsm[j][fp->state] = nstate; continue; case C_ALPH: for (j=0; j<=256; j++) if ('a'<=j&&j<='z' || 'A'<=j&&j<='Z' || UTF2(j) || UTF3(j) || UTF4(j) || j=='_') bigfsm[j][fp->state] = nstate; continue; case C_NUM: for (j='0'; j<='9'; j++) bigfsm[j][fp->state] = nstate; continue; default: bigfsm[fp->ch[i]][fp->state] = nstate; } } } /* install special cases for ? (trigraphs), \ (splicing), runes */ for (i=0; i<MAXSTATE; i++) { for (j=0; j<0xFF; j++) if (j=='?' || j=='\\' || UTF2(j) || UTF3(j) || UTF4(j)) { if (bigfsm[j][i]>0) bigfsm[j][i] = ~bigfsm[j][i]; bigfsm[j][i] &= ~QBSBIT; } if (bigfsm[EOFC][i]>=0) bigfsm[EOFC][i] = ~S_EOF; } } void fixlex(void) { /* do C++ comments? */ if (Cplusplus==0) bigfsm['/'][COM1] = bigfsm['x'][COM1]; } /* * fill in a row of tokens from input, terminated by NL or END * First token is put at trp->lp. * Reset is non-zero when the input buffer can be "rewound." * The value is a flag indicating that possible macros have * been seen in the row. */ int gettokens(Tokenrow *trp, int reset) { register int c, state, oldstate; register uchar *ip; register Token *tp, *maxp; int runelen; Source *s = cursource; int nmac = 0; tp = trp->lp; ip = s->inp; if (reset) s->lineinc = 0; maxp = &trp->bp[trp->max]; runelen = 1; for (;;) { continue2: if (tp>=maxp) { trp->lp = tp; tp = growtokenrow(trp); maxp = &trp->bp[trp->max]; } tp->type = UNCLASS; tp->hideset = 0; tp->t = ip; tp->wslen = 0; tp->flag = 0; state = START; for (;;) { oldstate = state; c = *ip; if ((state = bigfsm[c][state]) >= 0) { ip += runelen; runelen = 1; continue; } state = ~state; reswitch: switch (state&0177) { case S_SELF: ip += runelen; runelen = 1; case S_SELFB: tp->type = GETACT(state); tp->len = ip - tp->t; tp++; goto continue2; case S_NAME: /* like S_SELFB but with nmac check */ tp->type = NAME; tp->len = ip - tp->t; nmac |= quicklook(tp->t[0], tp->len>1?tp->t[1]:0); tp++; goto continue2; case S_WS: tp->wslen = ip - tp->t; tp->t = ip; state = START; continue; default: if ((state&QBSBIT)==0) { ip += runelen; runelen = 1; continue; } state &= ~QBSBIT; s->inp = ip; if (c=='?') { /* check trigraph */ if (trigraph(s)) { state = oldstate; continue; } goto reswitch; } if (c=='\\') { /* line-folding */ if (foldline(s)) { s->lineinc++; state = oldstate; continue; } goto reswitch; } if (UTF2(c)) { runelen = 2; goto reswitch; } if (UTF3(c)) { runelen = 3; goto reswitch; } if (UTF4(c)) { runelen = 4; goto reswitch; } error(WARNING, "Lexical botch in cpp"); ip += runelen; runelen = 1; continue; case S_EOF: tp->type = END; tp->len = 0; s->inp = ip; if (tp!=trp->bp && (tp-1)->type!=NL && cursource->fd!=-1) error(WARNING,"No newline at end of file"); trp->lp = tp+1; return nmac; case S_STNL: error(ERROR, "Unterminated string or char const"); case S_NL: tp->t = ip; tp->type = NL; tp->len = 1; tp->wslen = 0; s->lineinc++; s->inp = ip+1; trp->lp = tp+1; return nmac; case S_EOFSTR: error(FATAL, "EOF in string or char constant"); break; case S_COMNL: s->lineinc++; state = COM2; ip += runelen; runelen = 1; continue; case S_EOFCOM: error(WARNING, "EOF inside comment"); --ip; case S_COMMENT: ++ip; tp->t = ip; tp->t[-1] = ' '; tp->wslen = 1; state = START; continue; } break; } ip += runelen; runelen = 1; tp->len = ip - tp->t; tp++; } } /* have seen ?; handle the trigraph it starts (if any) else 0 */ int trigraph(Source *s) { int c; if (s->inp[1]!='?') return 0; c = 0; switch(s->inp[2]) { case '=': c = '#'; break; case '(': c = '['; break; case '/': c = '\\'; break; case ')': c = ']'; break; case '\'': c = '^'; break; case '<': c = '{'; break; case '!': c = '|'; break; case '>': c = '}'; break; case '-': c = '~'; break; } if (c) { *s->inp = c; memmove(s->inp+1, s->inp+3, s->inl-s->inp+2); s->inl -= 2; } return c; } int foldline(Source *s) { int ncr = 0; recheck: if (s->inp[ncr+1] == '\r') { /* nonstandardly, ignore CR before line-folding */ ncr++; goto recheck; } if (s->inp[ncr+1] == '\n') { memmove(s->inp, s->inp+2+ncr, s->inl-s->inp+3-ncr); s->inl -= 2+ncr; return 1; } return 0; } /* * Push down to new source of characters. * If fd>0 and str==NULL, then from a file `name'; * if fd==-1 and str, then from the string. */ Source * setsource(char *name, int fd, char *str) { Source *s = new(Source); int n, len; s->line = 1; s->lineinc = 0; s->fd = fd; s->filename = name; s->next = cursource; s->ifdepth = 0; cursource = s; /* slop at right for EOFC */ if (str) { len = strlen(str); s->inb = domalloc(len+4); strncpy((char *)s->inb, str, len); } else { len = 0; s->inb = nil; for(;;){ s->inb = dorealloc(s->inb, len + INS); if (s->fd<0 || (n=read(s->fd, (char *)s->inb + len, INS)) <= 0) break; len += n; } s->inb = dorealloc(s->inb, len + 4); } s->inp = s->inb; s->inl = s->inp+len; s->inl[0] = s->inl[1] = s->inl[2] = s->inl[3] = EOFC; return s; } void unsetsource(void) { Source *s = cursource; if (s->fd>=0) { close(s->fd); dofree(s->inb); } cursource = s->next; dofree(s); }