push.c

a little DFA compiler.

/* Generated by re2c */
#line 1 "push.re"
/*
 *  A push-model scanner example for re2c -f
 *  Written Mon Apr 11 2005 by [e-mail]
 *  This file is in the public domain.
 *
 */

// ----------------------------------------------------------------------

#include <fcntl.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#if defined(WIN32)

    typedef signed char     int8_t;
    typedef signed short    int16_t;
    typedef signed int      int32_t;

    typedef unsigned char   uint8_t;
    typedef unsigned short  uint16_t;
    typedef unsigned int    uint32_t;

#else

    #include <stdint.h>
    #include <unistd.h>

    #ifndef O_BINARY
        #define O_BINARY 0
    #endif

#endif

// ----------------------------------------------------------------------
#define TOKENS              \
                            \
    TOK(kEOF)               \
    TOK(kEOL)               \
    TOK(kUnknown)           \
    TOK(kIdentifier)        \
    TOK(kDecimalConstant)   \
                            \
    TOK(kEqual)             \
    TOK(kLeftParen)         \
    TOK(kRightParen)        \
    TOK(kMinus)             \
    TOK(kPlus)              \
    TOK(kStar)              \
    TOK(kSlash)             \
                            \
    TOK(kIf)                \
    TOK(kFor)               \
    TOK(kElse)              \
    TOK(kGoto)              \
    TOK(kBreak)             \
    TOK(kWhile)             \
    TOK(kReturn)            \


// ----------------------------------------------------------------------
static const char *tokenNames[] =
{
    #define TOK(x) #x,
        TOKENS
    #undef TOK
};

// ----------------------------------------------------------------------
class PushScanner
{
public:

    enum Token
    {
        #define TOK(x) x,
            TOKENS
        #undef TOK
    };

private:

    bool        eof;
    int32_t     state;

    uint8_t     *limit;
    uint8_t     *start;
    uint8_t     *cursor;
    uint8_t     *marker;

    uint8_t     *buffer;
    uint8_t     *bufferEnd;

    uint8_t     yych;
    uint32_t    yyaccept;

public:

    // ----------------------------------------------------------------------
    PushScanner()
    {
        limit = 0;
        start = 0;
        state = -1;
        cursor = 0;
        marker = 0;
        buffer = 0;
        eof = false;
        bufferEnd = 0;
    }

    // ----------------------------------------------------------------------
    ~PushScanner()
    {
    }

    // ----------------------------------------------------------------------
    void send(
        Token token
    )
    {
        size_t tokenSize = cursor-start;
        const char *tokenName = tokenNames[token];
        printf(
            "scanner is pushing out a token of type %d (%s)",
            token,
            tokenName
        );

        if(token==kEOF) putchar('\n');
        else
        {
            size_t tokenNameSize = strlen(tokenNames[token]);
            size_t padSize = 20-(20<tokenNameSize ? 20 : tokenNameSize);
            for(size_t i=0; i<padSize; ++i) putchar(' ');
            printf(" : ---->");

            fwrite(
                start,
                tokenSize,
                1,
                stdout
            );

            printf("<----\n");
        }
    }

    // ----------------------------------------------------------------------
    uint32_t push(
        const void  *input,
        ssize_t     inputSize
    )
    {
        printf(
            "scanner is receiving a new data batch of length %d\n"
            "scanner continues with saved state = %d\n",
            inputSize,
            state
        );

        /*
         * Data source is signaling end of file when batch size
         * is less than maxFill. This is slightly annoying because
         * maxFill is a value that can only be known after re2c does
         * its thing. Practically though, maxFill is never bigger than
         * the longest keyword, so given our grammar, 32 is a safe bet.
         */
        uint8_t null[64];
        const ssize_t maxFill = 32;
        if(inputSize<maxFill)
        {
            eof = true;
            input = null;
            inputSize = sizeof(null);
            memset(null, 0, sizeof(null));
        }

        /*
         * When we get here, we have a partially
         * consumed buffer which is in the following state:
         *                                                                last valid char        last valid buffer spot
         *                                                                v                      v
         * +-------------------+-------------+---------------+-------------+----------------------+
         * ^                   ^             ^               ^             ^                      ^
         * buffer              start         marker          cursor        limit                  bufferEnd
         * 
         * We need to stretch the buffer and concatenate the new chunk of input to it
         *
         */
        size_t used = limit-buffer;
        size_t needed = used+inputSize;
        size_t allocated = bufferEnd-buffer;
        if(allocated<needed)
        {
            size_t limitOffset = limit-buffer;
            size_t startOffset = start-buffer;
            size_t markerOffset = marker-buffer;
            size_t cursorOffset = cursor-buffer;

                buffer = (uint8_t*)realloc(buffer, needed);
                bufferEnd = needed+buffer;

            marker = markerOffset + buffer;
            cursor = cursorOffset + buffer;
            start = buffer + startOffset;
            limit = limitOffset + buffer;
        }
        memcpy(limit, input, inputSize);
        limit += inputSize;

        // The scanner starts here
        #define YYLIMIT         limit
        #define YYCURSOR        cursor
        #define YYMARKER        marker
        #define YYCTYPE         uint8_t

        #define SKIP(x)         { start = cursor; goto yy0; }
        #define SEND(x)         { send(x); SKIP();          }
        #define YYFILL(n)       { goto fill;                }

        #define YYGETSTATE()    state
        #define YYSETSTATE(x)   { state = (x);  }

    start:

        
#line 233 "<stdout>"
{
	YYCTYPE yych;
yy0:
	if((YYLIMIT - YYCURSOR) < 7) YYFILL(7);
	yych = *YYCURSOR;
	switch(yych) {
	case 0x00:	goto yy32;
	case 0x09:
	case 0x0B:
	case 0x0C:
	case 0x0D:
	case ' ':	goto yy30;
	case 0x0A:	goto yy28;
	case '(':	goto yy16;
	case ')':	goto yy18;
	case '*':	goto yy24;
	case '+':	goto yy22;
	case '-':	goto yy20;
	case '/':	goto yy26;
	case '0':
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
	case '9':	goto yy12;
	case '=':	goto yy14;
	case 'A':
	case 'B':
	case 'C':
	case 'D':
	case 'E':
	case 'F':
	case 'G':
	case 'H':
	case 'I':
	case 'J':
	case 'K':
	case 'L':
	case 'M':
	case 'N':
	case 'O':
	case 'P':
	case 'Q':
	case 'R':
	case 'S':
	case 'T':
	case 'U':
	case 'V':
	case 'W':
	case 'X':
	case 'Y':
	case 'Z':
	case '_':
	case 'a':
	case 'c':
	case 'd':
	case 'j':
	case 'k':
	case 'l':
	case 'm':
	case 'n':
	case 'o':
	case 'p':
	case 'q':
	case 's':
	case 't':
	case 'u':
	case 'v':
	case 'x':
	case 'y':
	case 'z':	goto yy10;
	case 'b':	goto yy7;
	case 'e':	goto yy5;
	case 'f':	goto yy4;
	case 'g':	goto yy6;
	case 'h':	goto yy11;
	case 'i':	goto yy2;
	case 'r':	goto yy9;
	case 'w':	goto yy8;
	default:	goto yy34;
	}
yy2:
	++YYCURSOR;
	switch((yych = *YYCURSOR)) {
	case 'f':	goto yy67;
	default:	goto yy39;
	}
yy3:
#line 246 "push.re"
	{ SEND(kIdentifier);     }
#line 328 "<stdout>"
yy4:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'o':	goto yy64;
	default:	goto yy39;
	}
yy5:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'l':	goto yy60;
	default:	goto yy39;
	}
yy6:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'o':	goto yy56;
	default:	goto yy39;
	}
yy7:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'r':	goto yy51;
	default:	goto yy39;
	}
yy8:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'h':	goto yy46;
	default:	goto yy39;
	}
yy9:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'e':	goto yy40;
	default:	goto yy39;
	}
yy10:
	yych = *++YYCURSOR;
	goto yy39;
yy11:
	yych = *++YYCURSOR;
	goto yy39;
yy12:
	++YYCURSOR;
	yych = *YYCURSOR;
	goto yy37;
yy13:
#line 247 "push.re"
	{ SEND(kDecimalConstant);}
#line 378 "<stdout>"
yy14:
	++YYCURSOR;
#line 249 "push.re"
	{ SEND(kEqual);          }
#line 383 "<stdout>"
yy16:
	++YYCURSOR;
#line 250 "push.re"
	{ SEND(kLeftParen);      }
#line 388 "<stdout>"
yy18:
	++YYCURSOR;
#line 251 "push.re"
	{ SEND(kRightParen);     }
#line 393 "<stdout>"
yy20:
	++YYCURSOR;
#line 252 "push.re"
	{ SEND(kMinus);          }
#line 398 "<stdout>"
yy22:
	++YYCURSOR;
#line 253 "push.re"
	{ SEND(kPlus);           }
#line 403 "<stdout>"
yy24:
	++YYCURSOR;
#line 254 "push.re"
	{ SEND(kStar);           }
#line 408 "<stdout>"
yy26:
	++YYCURSOR;
#line 255 "push.re"
	{ SEND(kSlash);          }
#line 413 "<stdout>"
yy28:
	++YYCURSOR;
#line 257 "push.re"
	{ SKIP();                }
#line 418 "<stdout>"
yy30:
	++YYCURSOR;
#line 258 "push.re"
	{ SKIP();                }
#line 423 "<stdout>"
yy32:
	++YYCURSOR;
#line 259 "push.re"
	{ send(kEOF); return 1;  }
#line 428 "<stdout>"
yy34:
	++YYCURSOR;
#line 260 "push.re"
	{ SEND(kUnknown);        }
#line 433 "<stdout>"
yy36:
	++YYCURSOR;
	if(YYLIMIT == YYCURSOR) YYFILL(1);
	yych = *YYCURSOR;
yy37:
	switch(yych) {
	case '0':
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
	case '9':	goto yy36;
	default:	goto yy13;
	}
yy38:
	++YYCURSOR;
	if(YYLIMIT == YYCURSOR) YYFILL(1);
	yych = *YYCURSOR;
yy39:
	switch(yych) {
	case '0':
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
	case '9':
	case 'A':
	case 'B':
	case 'C':
	case 'D':
	case 'E':
	case 'F':
	case 'G':
	case 'H':
	case 'I':
	case 'J':
	case 'K':
	case 'L':
	case 'M':
	case 'N':
	case 'O':
	case 'P':
	case 'Q':
	case 'R':
	case 'S':
	case 'T':
	case 'U':
	case 'V':
	case 'W':
	case 'X':
	case 'Y':
	case 'Z':
	case '_':
	case 'a':
	case 'b':
	case 'c':
	case 'd':
	case 'e':
	case 'f':
	case 'g':
	case 'h':
	case 'i':
	case 'j':
	case 'k':
	case 'l':
	case 'm':
	case 'n':
	case 'o':
	case 'p':
	case 'q':
	case 'r':
	case 's':
	case 't':
	case 'u':
	case 'v':
	case 'w':
	case 'x':
	case 'y':
	case 'z':	goto yy38;
	default:	goto yy3;
	}
yy40:
	yych = *++YYCURSOR;
	switch(yych) {
	case 't':	goto yy41;
	default:	goto yy39;
	}
yy41:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'u':	goto yy42;
	default:	goto yy39;
	}
yy42:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'r':	goto yy43;
	default:	goto yy39;
	}
yy43:
	yych = *++YYCURSOR;
	switch(yych) {
	case 'n':	goto yy44;
	default:	goto yy39;
	}
yy44:
	++YYCURSOR;
	switch((yych = *YYCURSOR)) {
	case '0':
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
	case '9':
	case 'A':
	case 'B':
	case 'C':
	case 'D':
	case 'E':
	case 'F':
	case 'G':
	case 'H':
	case 'I':
	case 'J':
	case 'K':
	case 'L':
	case 'M':
	case 'N':
	case 'O':
	case 'P':
	case 'Q':
	case 'R':
	case 'S':
	case 'T':
	case 'U':
	case 'V':
	case 'W':
	case 'X':
	case 'Y':
	case 'Z':
	case '_':
	case 'a':
	case 'b':
	case 'c':
	case 'd':
	case 'e':
	case 'f':
	case 'g':
	case 'h':
	case 'i':
	case 'j':
	case 'k':
	case 'l':
	case 'm':
	case 'n':