scan.c

Apriori 的C语言实现 .是非常好的

/*----------------------------------------------------------------------
  File    : scan.c
  Contents: scanner (lexical analysis of a character stream)
  Author  : Christian Borgelt
  History : 16.01.1996 file created
            21.02.1996 identifier recognition made more flexible
            17.03.1996 keyword tokens removed
            15.04.1996 duplicate state removed from sc_next
            29.07.1997 < and > declared active (for decision trees)
            08.09.1997 escape sequences in strings made possible
            11.09.1997 single characters stored also in scn->value
            08.02.1998 recover and error message functions added
            09.02.1998 bug in state S_NUMPT concerning "-." removed
            13.02.1998 token T_RGT ('->') added
            04.03.1998 returned tokens changed for some states
            17.04.1998 token T_LFT ('<-') added
            27.05.1998 token T_CMP (two char comparison operator) added
            31.05.1998 token conversion to number removed
            08.02.1999 reading from standard input made possible
            29.04.1999 quoted string parsing improved
            13.11.1999 token string length stored in scn->len
            23.11.2000 functions sc_fmtlen and sc_format added
            15.07.2001 scanner made an object, state definitions added
            16.07.2001 characters with code > 127 made printable
                       look ahead functionality added (sc_back)
            02.02.2006 token T_DASH (undirected edge '--') added
----------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <assert.h>
#include "scan.h"
#ifdef STORAGE
#include "storage.h"
#endif

/*----------------------------------------------------------------------
  Preprocessor Definitions
----------------------------------------------------------------------*/
#ifdef SC_SCAN
/* --- character classes --- */
#define C_ILLEGAL    0          /* illegal character */
#define C_SPACE      1          /* white space, e.g. ' ' '\t' '\n' */
#define C_LETTER     2          /* letter or underscore '_' */
#define C_DIGIT      3          /* digit */
#define C_POINT      4          /* point, '.' */
#define C_SIGN       5          /* sign,  '+' or '-' */
#define C_SLASH      6          /* slash, '/' */
#define C_QUOTE      7          /* quote, e.g. '"' '`' */
#define C_CMPOP      8          /* comparison operator, e.g. '<' */
#define C_ACTIVE     9          /* active characters, e.g. ',' '(' */

/* --- scanner states --- */
#define S_SPACE      0          /* skipping white space */
#define S_ID         1          /* reading identifier */
#define S_NUMDIG     2          /* reading number, digit */
#define S_NUMPT      3          /* reading number, decimal point */
#define S_FRAC       4          /* reading number, digit and point */
#define S_EXPIND     5          /* reading exponent, indicator */
#define S_EXPSGN     6          /* reading exponent, sign */
#define S_EXPDIG     7          /* reading exponent, digit */
#define S_SIGN       8          /* sign read */
#define S_CMPOP      9          /* reading comparison operator */
#define S_STRING    10          /* reading quoted string */
#define S_ESC       11          /* reading escaped character */
#define S_OCT1      12          /* reading octal  number, 1 digit */
#define S_OCT2      13          /* reading octal  number, 2 digits */
#define S_HEX1      14          /* reading hexad. number, 1 digit */
#define S_HEX2      15          /* reading hexad. number, 2 digits */
#define S_SLASH     16          /* slash read */
#define S_CPPCOM    17          /* reading C++ comment */
#define S_CCOM1     18          /* reading C comment */
#define S_CCOM2     19          /* reading C comment, possible end */
#define S_CCOM3     20          /* reading C comment, possible start */

/* --- functions --- */
#define UNGETC(s,c)  do { if ((c) ==  EOF) break; \
                          if ((c) == '\n') (s)->line--; \
                          ungetc(c, (s)->file); } while (0)

/* --- additional error codes --- */
#define E_UNKNOWN   (-11)       /* unknown error */
#define MSGOFFSET   (-16)       /* offset for add. error messages */

/* --- texts --- */
#ifdef GERMAN                   /* deutsche Texte */
#define FILETXT     "Datei"
#define LINETXT     "Zeile"
#else                           /* English texts */
#define FILETXT     "file"
#define LINETXT     "line"
#endif  /* #ifdef GERMAN .. #else .. */
#endif  /* #ifdef SC_SCAN */

/*----------------------------------------------------------------------
  Constants
----------------------------------------------------------------------*/
static const char _scftab[256] = {  /* scanable form classes */
        /* NUL  SOH  STX  ETX  EOT  ENQ  ACK  BEL */
/* 00 */    2,   2,   2,   2,   2,   2,   2,  'a',
        /*  BS   HT   LF   VT   FF   CR   SO   SI */
           'b', 't', 'n', 'v', 'f', 'r',  2,   2,
        /* DLE  DC1  DC2  DC3  DC4  NAK  SYN  ETB */
/* 10 */    2,   2,   2,   2,   2,   2,   2,   2,
        /* CAN   EM  SUB  ESC   FS   GS   RS   US */
            2,   2,   2,   2,   2,   2,   2,   2,
        /* ' '  '!'  '"'  '#'  '$'  '%'  '&'  ''' */
/* 20 */    1,   1,  '"',  1,   1,   1,   1,   1,
        /* '('  ')'  '*'  '+'  ','  '-'  '.'  '/' */
            1,   1,   1,   0,   1,   0,   0,   1,
        /* '0'  '1'  '2'  '3'  '4'  '5'  '6'  '7' */
/* 30 */    0,   0,   0,   0,   0,   0,   0,   0,
        /* '8'  '9'  ':'  ';'  '<'  '='  '>'  '?' */
            0,   0,   1,   1,   1,   1,   1,   1,
        /* '@'  'A'  'B'  'C'  'D'  'E'  'F'  'G' */
/* 40 */    1,   0,   0,   0,   0,   0,   0,   0,
        /* 'H'  'I'  'J'  'K'  'L'  'M'  'N'  'O' */
            0,   0,   0,   0,   0,   0,   0,   0,
        /* 'P'  'Q'  'R'  'S'  'T'  'U'  'V'  'W' */
/* 50 */    0,   0,   0,   0,   0,   0,   0,   0,
        /* 'X'  'Y'  'Z'  '['  '\'  ']'  '^'  '_' */
            0,   0,   0,   1, '\\',  1,   1,   0,
        /* '`'  'a'  'b'  'c'  'd'  'e'  'f'  'g' */
/* 60 */    1,   0,   0,   0,   0,   0,   0,   0,
        /* 'h'  'i'  'j'  'k'  'l'  'm'  'n'  'o' */
            0,   0,   0,   0,   0,   0,   0,   0,
        /* 'p'  'q'  'r'  's'  't'  'u'  'v'  'w' */
/* 70 */    0,   0,   0,   0,   0,   0,   0,   0,
        /* 'x'  'y'  'z'  '{'  '|'  '}'  '~'  DEL */
            0,   0,   0,   1,   1,   1,   1,   2,
/* 80 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1,
/* 90 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1,
/* a0 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1,
/* b0 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1,
/* c0 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1,
/* d0 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1,
/* e0 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1,
/* f0 */    1,   1,   1,   1,   1,   1,   1,   1,
            1,   1,   1,   1,   1,   1,   1,   1 };

#ifdef SC_SCAN
static const char _ccltab[256] = {  /* character classes */
        /* NUL  SOH  STX  ETX  EOT  ENQ  ACK  BEL */
/* 00 */    0,   0,   0,   0,   0,   0,   0,   0,
        /*  BS   HT   LF   VT   FF   CR   SO   SI */
            0,   1,   1,   1,   1,   1,   0,   0,
        /* DLE  DC1  DC2  DC3  DC4  NAK  SYN  ETB */
/* 10 */    0,   0,   0,   0,   0,   0,   0,   0,
        /* CAN   EM  SUB  ESC   FS   GS   RS   US */
            0,   0,   0,   0,   0,   0,   0,   0,
        /* ' '  '!'  '"'  '#'  '$'  '%'  '&'  ''' */
/* 20 */    1,   8,   7,   9,   9,   9,   9,   7,
        /* '('  ')'  '*'  '+'  ','  '-'  '.'  '/' */
            9,   9,   9,   5,   9,   5,   4,   6,
        /* '0'  '1'  '2'  '3'  '4'  '5'  '6'  '7' */
/* 30 */    3,   3,   3,   3,   3,   3,   3,   3,
        /* '8'  '9'  ':'  ';'  '<'  '='  '>'  '?' */
            3,   3,   9,   9,   8,   8,   8,   9,
        /* '@'  'A'  'B'  'C'  'D'  'E'  'F'  'G' */
/* 40 */    0,   2,   2,   2,   2,   2,   2,   2,
        /* 'H'  'I'  'J'  'K'  'L'  'M'  'N'  'O' */
            2,   2,   2,   2,   2,   2,   2,   2,
        /* 'P'  'Q'  'R'  'S'  'T'  'U'  'V'  'W' */
/* 50 */    2,   2,   2,   2,   2,   2,   2,   2,
        /* 'X'  'Y'  'Z'  '['  '\'  ']'  '^'  '_' */
            2,   2,   2,   9,   9,   9,   9,   2,
        /* '`'  'a'  'b'  'c'  'd'  'e'  'f'  'g' */
/* 60 */    7,   2,   2,   2,   2,   2,   2,   2,
        /* 'h'  'i'  'j'  'k'  'l'  'm'  'n'  'o' */
            2,   2,   2,   2,   2,   2,   2,   2,
        /* 'p'  'q'  'r'  's'  't'  'u'  'v'  'w' */
/* 70 */    2,   2,   2,   2,   2,   2,   2,   2,
        /* 'x'  'y'  'z'  '{'  '|'  '}'  '~'  DEL */
            2,   2,   2,   9,   9,   9,   9,   0,
/* 80 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0,
/* 90 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0,
/* a0 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0,
/* b0 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0,
/* c0 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0,
/* d0 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0,
/* e0 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0,
/* f0 */    0,   0,   0,   0,   0,   0,   0,   0,
            0,   0,   0,   0,   0,   0,   0,   0 };

#ifdef GERMAN                      /* deutsche Texte */
static const char *_errmsgs[] = {  /* error messages */
  /* E_NONE      0 */  "kein Fehler",
  /* E_NOMEM    -1 */  "nicht genug Speicher",
  /* E_FOPEN    -2 */  "謋fnen fehlgeschlagen",
  /* E_FREAD    -3 */  "Lesefehler",
  /* E_FWRITE   -4 */  "Schreibfehler",
  /* E_ILLCHR   -5 */  "ung黮tiges Zeichen '%c' (0x%02x)",
  /* E_BUFOVF   -6 */  "Puffer黚erlauf",
  /* E_UNTSTR   -7 */  "unbeendete Zeichenkette",
  /* E_UNTCOM   -8 */  "unerwartetes Dateiende in Kommentar "
                       "(Anfang in Zeile %d)",
  /* E_STATE    -9 */  "ung黮tiger Scannerzustand",
  /* E_GARBAGE -10 */  "ung黮tiger Text am Dateiende",
  /* E_UNKNOWN -11 */  "unbekannter Fehler"
};
#else                              /* English texts */
static const char *_errmsgs[] = {  /* error messages */
  /* E_NONE      0 */  "no error",
  /* E_NOMEM    -1 */  "not enough memory",
  /* E_FOPEN    -2 */  "file open failed",
  /* E_FREAD    -3 */  "file read failed",
  /* E_FWRITE   -4 */  "file write failed",
  /* E_ILLCHR   -5 */  "illegal character '%c' (0x%02x)",
  /* E_BUFOVF   -6 */  "scan buffer overflow",
  /* E_UNTSTR   -7 */  "unterminated string",
  /* E_UNTCOM   -8 */  "unexpected end of file in comment "
                       "started on line %d",
  /* E_STATE    -9 */  "illegal scanner state",
  /* E_GARBAGE -10 */  "garbage at end of file",
  /* E_UNKNOWN -11 */  "unknown error"
};
#endif  /* #ifdef GERMAN .. #else .. */
#endif  /* #ifdef SC_SCAN */

/*----------------------------------------------------------------------
  Auxiliary Functions
----------------------------------------------------------------------*/
#ifdef SC_SCAN

static int _swap (SCAN *scan)
{                               /* --- swap token information */
  int t;                        /* swap buffer */

  if (scan->value == scan->buf[0]) scan->value = scan->buf[1];
  else                             scan->value = scan->buf[0];
  t = scan->plen;   scan->plen   = scan->len;   scan->len   = t;
  t = scan->pline;  scan->pline  = scan->line;  scan->line  = t;
  t = scan->ptoken; scan->ptoken = scan->token; scan->token = t;
  return t;                     /* return the new token */
}  /* _swap() */

#endif
/*----------------------------------------------------------------------
  Main Functions
----------------------------------------------------------------------*/