clib.arc

一个表达式解析器

>>> CLIB.H 1617
/*
** CLIB.H -- Definitions for Small-C library functions.
**
** Copyright 1983  L. E. Payne and J. E. Hendrix
*/

/*
** Misc parameters
*/
#define MAXFILES 20  /* maximum open files */
#define DOSEOF   26  /* DOS end-of-file byte */
#define ARCHIVE  32  /* file archive bit */

/*
** DOS function calls
*/
#define CREATE   60  /* make file */
#define OPEN     61  /* open file */
#define CLOSE    62  /* close file or device */
#define READ     63  /* read from a file */
#define WRITE    64  /* write to a file */
#define DELETE   65  /* delete file */
#define SEEK     66  /* seek within a file */
#define CONTROL  68  /* control device */
#define FORCE    70  /* force use of a handle */
#define RETDOS   76  /* close files and return to DOS */
#define FNDFIL   78  /* find first occurrence of a file */
#define FNDNXT   79  /* find next occurrence of a file */
#define RENAME   86  /* rename file */

/*
** File status bits
*/
#define OPNBIT   1  /* open condition */
#define EOFBIT   2  /* end-of-file condition */
#define ERRBIT   4  /* error condition */

/*
** File positioning origins
*/
#define FROM_BEG  0  /* from beginning of file */
#define FROM_CUR  1  /* from current position */
#define FROM_END  2  /* from end of file */

/*
** Buffer usage codes
** NULL means the buffer is not used.
*/
#define EMPTY     1  /* buffer is currently empty */
#define IN        2  /* buffer is currently holding input data */
#define OUT       3  /* buffer is currently holding output data */

/*
** ASCII characters
*/
#define ABORT    3
#define RUB      8
#define PAUSE   19
#define WIPE    24
#define DEL    127

>>> ABS.C 117
/*
** abs -- returns absolute value of nbr
*/
abs(nbr)  int nbr; {
  if(nbr < 0) return (-nbr);
  return (nbr);
  }

>>> ATOI.C 259
/*
** atoi(s) - convert s to integer.
*/
atoi(s) char *s; {
  int sign, n;
  while(isspace(*s)) ++s;
  sign = 1;
  switch(*s) {
    case '-': sign = -1;
    case '+': ++s;
    }
  n = 0;
  while(isdigit(*s)) n = 10 * n + *s++ - '0';
  return (sign * n);
  }

>>> ATOIB.C 435
/*
** atoib(s,b) - Convert s to "unsigned" integer in base b.
**              NOTE: This is a non-standard function.
*/
atoib(s, b) char *s; int b; {
  int n, digit;
  n = 0;
  while(isspace(*s)) ++s;
  while((digit = (127 & *s++)) >= '0') {
    if(digit >= 'a')      digit -= 87;
    else if(digit >= 'A') digit -= 55;
    else                  digit -= '0';
    if(digit >= b) break;
    n = b * n + digit;
    }
  return (n);
  }


>>> AUXBUF.C 786
#include "stdio.h"
#include "clib.h"
extern int
  _bufsiz[MAXFILES],  /* size of buffer */
  _bufptr[MAXFILES];  /* aux buffer address */

/*
** auxbuf -- allocate an auxiliary input buffer for fd
**   fd = file descriptor of an open file
** size = size of buffer to be allocated
** Returns NULL on success, else ERR.
** Note: Ungetc() still works.
**       A 2nd call allocates a new buffer replacing old one.
**       If fd is a device, buffer is allocated but ignored.
**       Buffer stays allocated when fd is closed or new one is allocated.
**       May be used on a closed fd.
*/
auxbuf(fd, size) int fd; char *size; {   /* fake unsigned */
  if(!size || avail(NO) < size) return (ERR);
  _bufptr[fd] = malloc(size);
  _bufsiz[fd] = size;
  _empty(fd, NO);
  return (NULL);
  }

>>> AVAIL.C 347
extern char *_memptr;
/*
** Return the number of bytes of available memory.
** In case of a stack overflow condition, if 'abort'
** is non-zero the program aborts with an 'S' clue,
** otherwise zero is returned.
*/
avail(abort) int abort; {
  char x;
  if(&x < _memptr) {
    if(abort) exit(1);
    return (0);
    }
  return (&x - _memptr);
  }

>>> BSEEK.C 727
#include "stdio.h"
#include "clib.h"
extern int _nextc[], _bufuse[];
/*
** Position fd to the character in file indicated by "offset."
** "Offset" is the address of a long integer or array of two
** integers containing the offset, low word first.
** 
**     BASE     OFFSET-RELATIVE-TO
**       0      beginning of file
**       1      current byte in file
**       2      end of file (minus offset)
**
** Returns NULL on success, else EOF.
*/
bseek(fd, offset, base) int fd, offset[], base; {
  int hi, lo;
  if(!_mode(fd) || !_bufuse[fd]) return (EOF);
  if(_adjust(fd)) return (EOF);
  lo = offset[0];
  hi = offset[1];
  if(!_seek(base, fd, &hi, &lo)) return (EOF);
  _nextc[fd] = EOF;
  _clreof(fd);
  return (NULL);
  }

>>> BTELL.C 447
#include "stdio.h"
#include "clib.h"
extern int _bufuse[];
/*
** Retrieve offset to next character in fd.
** "Offset" must be the address of a long int or
** a 2-element int array.  The offset is placed in
** offset in low, high order.
*/
btell(fd, offset) int fd, offset[]; {
  if(!_mode(fd) || !_bufuse[fd]) return (EOF);
  if(_adjust(fd)) return (EOF);
  offset[0] = offset[1] = 0;
  _seek(FROM_CUR, fd, offset+1, offset);
  return (NULL);
  }
>>> CALL.ASM 3939
;
; Small-C Run Time Library for MS/PC-DOS
;
        extrn   __main: near
        extrn    _exit: near
        extrn   __memptr: word

data   segment public
        dw      1
data   ends

stack   segment stack
        dw      32 dup(?)
stack   ends

code    segment public
        assume  cs:code
start:
        mov     ax,data         ; set data segment for program
        mov     ds,ax
        mov     ax,es:[2]       ; paragraphs of memory on system
        sub     ax,data         ; paragraphs beyond code segment
        cmp     ah,10h          ; more than 64K?
        jb      start_1         ; no
        mov     ax,1000h        ; only use 64K
start_1:
        mov     cl,4
        shl     ax,cl           ; byte offset to end of data/free/stack
        cli                     ; disable interrupts
        mov     bx,ds
        mov     ss,bx           ; make data and stack segments coincide
        mov     sp,ax           ; top of stack = end of data/free/stack
        push    ax              ; force sp non-zero (if 64K used)
        sti                     ; reenable interrupts
        mov     ax,stack        ; paragraph following data
        sub     ax,data         ; number of data paragraphs
        shl     ax,cl           ; number of data bytes (offset to free/stack)
        mov     bx,ax
        inc     bh              ; adjust for minimum stack space
        cmp     bx,sp           ; enough memory?
        jb      start_2         ; yes
        mov     ax,1            ; no, terminate with exit code 1
        push    ax
        call    _exit
start_2:
        mov     __memptr,ax     ; set memory allocation pointer
;
; ------------ release unused memory -----------
; ------ cannot run debug with this code -------
;        mov     bx,sp
;        mov     ah,4AH
;        int     21H
; ----------------------------------------------
;
; make sure that es -> psp, because __main requires it
;
        jmp     __main          ; __main never returns

        public  _ccargc
_ccargc:
        mov     al,cl
        xor     ah,ah
        ret

;
; Test if Secondary (BX) <oper> Primary (AX)
;-------------------------- MASM version
;compare macro   name, cond
;        public  __&name
;__&name:
;        cmp     ax,bx
;        j&cond  true
;        xor     ax,ax   ; returns zero
;        ret
;        endm
;-------------------------- ASM version
compare macro   name, cond
        public  __?1
__?1:
        cmp     ax,bx
        j?2     true
        xor     ax,ax   ; returns zero
        ret
        endm
;--------------------------
        compare ult,a
        compare ugt,b
        compare ule,ae
        compare uge,be
        compare eq,e
        compare ne,ne
        compare lt,g
        compare gt,l
        compare le,ge
        compare ge,le

;
; Logical Negate of Primary
;
        public  __lneg
__lneg:
        or      ax,ax
        jnz     false
true:   mov     ax,1    ; returns one
        ret
false:  xor     ax,ax   ; returns zero
        ret
;
;
; execute "switch" statement
;
;  ax  =  switch value
; (sp) -> switch table
;         dw addr1, value1
;         dw addr2, value2
;         ...
;         dw 0
;        [jmp default]
;         continuation
;
        public  __switch
__switch:
        pop     bx              ; bx -> switch table
        jmp     skip            ; skip the pre-increment
back:
        add     bx,4
skip:   mov     cx,cs:[bx]
        jcxz    default         ; end of table -- jump out
        cmp     ax,cs:[bx+2]
        jnz     back
        jmp     cx              ; match -- jump to case
default:
        inc     bx
        inc     bx
        jmp     bx              ; jump to default/continuation
;
; dummy entry point to resolve the external reference _LINK
; which is no longer generated by Small-C but which exists in
; library modules and .OBJ files compiled by earlier versions
; of Small-C
        public  __link
__link: ret

code ends
        end     start

>>> CALLOC.C 315
#include "stdio.h"
/*
** Cleared-memory allocation of n items of size bytes.
** n     = Number of items to allocate space for.
** size  = Size of the items in bytes.
** Returns the address of the allocated block,
** else NULL for failure.
*/
calloc(n, size) unsigned n, size; {
  return (_alloc(n*size, YES));
  }

>>> CLEARERR.C 152
#include "stdio.h"
#include "clib.h"
extern int _status[];
/*
** Clear error status for fd.
*/
clearerr(fd) int fd; {
  if(_mode(fd)) _clrerr(fd);
  }

>>> CSEEK.C 1539
#include "stdio.h"
#include "clib.h"
extern int _nextc[], _bufuse[];
/*
** Position fd to the 128-byte record indicated by
** "offset" relative to the point indicated by "base."
** 
**     BASE     OFFSET-RELATIVE-TO
**       0      first record
**       1      current record
**       2      end of file (last record + 1)
**              (offset should be minus)
**
** Returns NULL on success, else EOF.
*/
cseek(fd, offset, base) int fd, offset, base; {
  int newrec, oldrec, hi, lo;
  if(!_mode(fd) || !_bufuse[fd]) return (EOF);
  if(_adjust(fd)) return (EOF);
  switch (base) {
     case 0: newrec = offset;
             break;
     case 1: oldrec = ctell(fd);
             goto calc;
     case 2: hi = lo = 0;
             if(!_seek(FROM_END, fd, &hi, &lo)) return (EOF);
             oldrec = ((lo >> 7) & 511) | (hi << 9);
     calc:
             newrec = oldrec + offset;
             break;
    default: return (EOF);
    }
  lo = (newrec << 7);       /* convert newrec to long int */
  hi = (newrec >> 9) & 127;
  if(!_seek(FROM_BEG, fd, &hi, &lo)) return (EOF);
  _nextc[fd] = EOF;
  _clreof(fd);
  return (NULL);
  }

/*
** Position fd to the character indicated by
** "offset" within current 128-byte record.
** Must be on record boundary.
**
** Returns NULL on success, else EOF.
*/
cseekc(fd, offset) int fd, offset; {
  int hi, lo;
  if(!_mode(fd) || isatty(fd) ||
     ctellc(fd) || offset < 0 || offset > 127) return (EOF);
  hi = 0; lo = offset;
  if(!_seek(FROM_CUR, fd, &hi, &lo)) return (EOF);
  return (NULL);
  }

>>> CSYSLIB.C 9708
/*
** CSYSLIB -- System-Level Library Functions
*/

#include "stdio.h"
#include "clib.h"

/*
****************** System Variables ********************
*/

int
  _cnt=1,             /* arg count for main */
  _vec[20],           /* arg vectors for main */
  _status[MAXFILES] = {OPNBIT, OPNBIT, OPNBIT, OPNBIT, OPNBIT},
  _cons  [MAXFILES],  /* fast way to tell if file is the console */
  _nextc [MAXFILES] = {EOF, EOF, EOF, EOF, EOF},
  _bufuse[MAXFILES],  /* current buffer usage: NULL, EMPTY, IN, OUT */
  _bufsiz[MAXFILES],  /* size of buffer */
  _bufptr[MAXFILES],  /* aux buffer address */
  _bufnxt[MAXFILES],  /* address of next byte in buffer */
  _bufend[MAXFILES],  /* address of end-of-data in buffer */
  _bufeof[MAXFILES];  /* true if current buffer ends file */

char
 *_memptr,           /* pointer to free memory. */
  _arg1[]="*";       /* first arg for main */

/*
*************** System-Level Functions *****************
*/

/*
**  Process command line, allocate default buffer to each fd,
**  execute main(), and exit to DOS.  Must be executed with es=psp.
**  Small default buffers are allocated because a high price is paid for
**  byte-by-byte calls to DOS.  Tests gave these results for a simple
**  copy program:
**
**          chunk size       copy time in seconds
**              1                    36
**              5                    12
**             25                     6
**             50                     6
*/
_main() {
  int fd;
  _parse();
  for(fd = 0; fd < MAXFILES; ++fd) auxbuf(fd, 32);
  if(!isatty(stdin))  _bufuse[stdin]  = EMPTY;
  if(!isatty(stdout)) _bufuse[stdout] = EMPTY;
  main(_cnt, _vec);
  exit(0);
  }

/*
** Parse command line and setup argc and argv.
** Must be executed with es == psp
*/
_parse() {
  char *ptr;
#asm
  mov     cl,es:[80h]  ; get parameter string length
  mov     ch,0       
  push    cx           ; save it
  inc     cx
  push    cx           ; 1st __alloc() arg
  mov     ax,1
  push    ax           ; 2nd __alloc() arg
  call    __alloc      ; allocate zeroed memory for args
  add     sp,4
  mov     [bp-2],ax    ; ptr = addr of allocated memory
  pop     cx
  push    es           ; exchange
  push    ds           ; es         (source)
  pop     es           ;    and
  pop     ds           ;        ds  (destination)
  mov     si,81h       ; source offset
  mov     di,[bp-2]    ; destination offset
  rep     movsb        ; move string
  mov     al,0
  stosb                ; terminate with null byte
  push    es
  pop     ds           ; restore ds
#endasm
  _vec[0]=_arg1;       /* first arg = "*" */
  while (*ptr) {
    if(isspace(*ptr)) {++ptr; continue;}
    if(_cnt < 20) _vec[_cnt++] = ptr;
    while(*ptr) {
      if(isspace(*ptr)) {*ptr = NULL; ++ptr; break;}
      ++ptr;
      }
    }
  }