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/*
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/*
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 * a variety of helper functions
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 * a variety of helper functions
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 * Copyright (C) 2021 Mateusz Viste
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 * Copyright (C) 2021 Mateusz Viste
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 */
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 */
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 5 
 
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#include "helpers.h"
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#include "helpers.h"
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 7 
 
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/* case-insensitive comparison of strings, returns non-zero on equality */
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/* case-insensitive comparison of strings, returns non-zero on equality */
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int imatch(const char *s1, const char *s2) {
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int imatch(const char *s1, const char *s2) {
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  for (;;) {
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  for (;;) {
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    char c1, c2;
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    char c1, c2;
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    c1 = *s1;
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    c1 = *s1;
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    c2 = *s2;
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    c2 = *s2;
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    if ((c1 >= 'a') && (c1 <= 'z')) c1 -= ('a' - 'A');
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    if ((c1 >= 'a') && (c1 <= 'z')) c1 -= ('a' - 'A');
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    if ((c2 >= 'a') && (c2 <= 'z')) c2 -= ('a' - 'A');
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    if ((c2 >= 'a') && (c2 <= 'z')) c2 -= ('a' - 'A');
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    /* */
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    /* */
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    if (c1 != c2) return(0);
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    if (c1 != c2) return(0);
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    if (c1 == 0) return(1);
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    if (c1 == 0) return(1);
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    s1++;
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    s1++;
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    s2++;
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    s2++;
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  }
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  }
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}
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}
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 24 
 
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/* returns zero if s1 starts with s2 */
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/* returns zero if s1 starts with s2 */
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int strstartswith(const char *s1, const char *s2) {
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int strstartswith(const char *s1, const char *s2) {
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  while (*s2 != 0) {
 27 
  while (*s2 != 0) {
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    if (*s1 != *s2) return(-1);
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    if (*s1 != *s2) return(-1);
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    s1++;
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    s1++;
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    s2++;
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    s2++;
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  }
 31 
  }
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  return(0);
 32 
  return(0);
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}
 33 
}
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 34 
 
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 35 
 
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/* outputs a NULL-terminated string to stdout */
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/* outputs a NULL-terminated string to stdout */
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void output_internal(const char *s, unsigned short nl) {
 37 
void output_internal(const char *s, unsigned short nl) {
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  _asm {
 38 
  _asm {
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    mov ah, 0x02 /* AH=9 - write character in DL to stdout */
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    mov ah, 0x02 /* AH=9 - write character in DL to stdout */
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    mov si, s
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    mov si, s
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    cld          /* clear DF so lodsb increments SI */
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    cld          /* clear DF so lodsb increments SI */
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    NEXTBYTE:
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    NEXTBYTE:
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    lodsb /* load byte from DS:SI into AL, SI++ */
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    lodsb /* load byte from DS:SI into AL, SI++ */
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    mov dl, al
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    mov dl, al
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    or al, 0  /* is al == 0? */
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    or al, 0  /* is al == 0? */
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    jz DONE
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    jz DONE
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    int 0x21
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    int 0x21
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    jmp NEXTBYTE
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    jmp NEXTBYTE
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    DONE:
 49 
    DONE:
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    or nl, 0
 50 
    or nl, 0
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    jz FINITO
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    jz FINITO
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    /* print out a CR/LF trailer if nl set */
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    /* print out a CR/LF trailer if nl set */
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    mov dl, 0x0D /* CR */
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    mov dl, 0x0D /* CR */
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    int 0x21
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    int 0x21
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    mov dl, 0x0A /* LF */
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    mov dl, 0x0A /* LF */
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    int 0x21
 56 
    int 0x21
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    FINITO:
 57 
    FINITO:
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  }
 58 
  }
59 
}
 59 
}
60 
 
 60 
 
61 
 
 61 
 
62 
/* find first matching files using a FindFirst DOS call
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/* find first matching files using a FindFirst DOS call
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 * returns 0 on success or a DOS err code on failure */
 63 
 * returns 0 on success or a DOS err code on failure */
64 
unsigned short findfirst(struct DTA *dta, const char *pattern, unsigned short attr) {
 64 
unsigned short findfirst(struct DTA *dta, const char *pattern, unsigned short attr) {
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  unsigned short res = 0;
 65 
  unsigned short res = 0;
66 
  _asm {
 66 
  _asm {
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    /* set DTA location */
 67 
    /* set DTA location */
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    mov ah, 0x1a
 68 
    mov ah, 0x1a
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    mov dx, dta
 69 
    mov dx, dta
70 
    int 0x21
 70 
    int 0x21
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    /* */
 71 
    /* */
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    mov ah, 0x4e    /* FindFirst */
 72 
    mov ah, 0x4e    /* FindFirst */
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    mov dx, pattern
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    mov dx, pattern
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    mov cx, attr
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    mov cx, attr
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    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
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    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
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    jnc DONE
 76 
    jnc DONE
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    mov [res], ax
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    mov [res], ax
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    DONE:
 78 
    DONE:
79 
  }
 79 
  }
80 
  return(res);
 80 
  return(res);
81 
}
 81 
}
82 
 
 82 
 
83 
 
 83 
 
84 
/* find next matching, ie. continues an action intiated by findfirst() */
 84 
/* find next matching, ie. continues an action intiated by findfirst() */
85 
unsigned short findnext(struct DTA *dta) {
 85 
unsigned short findnext(struct DTA *dta) {
86 
  unsigned short res = 0;
 86 
  unsigned short res = 0;
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  _asm {
 87 
  _asm {
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    mov ah, 0x4f    /* FindNext */
 88 
    mov ah, 0x4f    /* FindNext */
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    mov dx, dta
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    mov dx, dta
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    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
 90 
    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
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    jnc DONE
 91 
    jnc DONE
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    mov [res], ax
 92 
    mov [res], ax
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    DONE:
 93 
    DONE:
94 
  }
 94 
  }
95 
  return(res);
 95 
  return(res);
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}
 96 
}
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 97 
 
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 98 
 
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 99 
/* print s string and wait for a single key press from stdin. accepts only
- 
 
 100 
 * key presses defined in the c ASCIIZ string. returns offset of pressed key
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 101 
 * in string. keys in c MUST BE UPPERCASE! */
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 102 
unsigned short askchoice(const char *s, const char *c) {
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 103 
  unsigned short res;
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 104 
  char key = 0;
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 105 
 
- 
 
 106 
  AGAIN:
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 107 
  output(s);
- 
 
 108 
  output(" ");
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 109 
 
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 110 
  _asm {
- 
 
 111 
    push ax
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 112 
    push dx
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 113 
 
- 
 
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    mov ax, 0x0c01 /* clear input buffer and execute getchar (INT 21h,AH=1) */
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 115 
    int 0x21
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    /* if AL == 0 then this is an extended character */
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    test al, al
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    jnz GOTCHAR
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 119 
    mov ah, 0x08   /* read again to flush extended char from input buffer */
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 120 
    int 0x21
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    xor al, al     /* all extended chars are ignored */
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 122 
    GOTCHAR:       /* received key is in AL now */
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    mov [key], al  /* save key */
- 
 
 124 
 
- 
 
 125 
    /* print a cr/lf */
- 
 
 126 
    mov ah, 0x02
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 127 
    mov dl, 0x0D
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 128 
    int 0x21
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    mov dl, 0x0A
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 130 
    int 0x21
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 131 
 
- 
 
 132 
    pop dx
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 133 
    pop ax
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 134 
  }
- 
 
 135 
 
- 
 
 136 
  /* ucase() result */
- 
 
 137 
  if ((key >= 'a') && (key <= 'z')) key -= ('a' - 'A');
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 138 
 
- 
 
 139 
  /* is there a match? */
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  for (res = 0; c[res] != 0; res++) if (c[res] == key) return(res);
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 141 
 
- 
 
 142 
  goto AGAIN;
- 
 
 143 
}
- 
 
 144 
 
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 145 
 
- 
 
 146 
/* converts a path to its canonic representation */
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 147 
void file_truename(const char *src, char *dst) {
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 148 
  _asm {
- 
 
 149 
    mov ah, 0x60  /* query truename, DS:SI=src, ES:DI=dst */
- 
 
 150 
    push ds
- 
 
 151 
    pop es
- 
 
 152 
    mov si, src
- 
 
 153 
    mov di, dst
- 
 
 154 
    int 0x21
- 
 
 155 
  }
- 
 
 156 
}
- 
 
 157 
 
- 
 
 158 
 
- 
 
 159 
/* returns DOS attributes of file, or -1 on error */
- 
 
 160 
int file_getattr(const char *fname) {
- 
 
 161 
  int res = -1;
- 
 
 162 
  _asm {
- 
 
 163 
    mov ax, 0x4300  /* query file attributes, fname at DS:DX */
- 
 
 164 
    mov dx, fname
- 
 
 165 
    int 0x21        /* CX=attributes if CF=0, otherwise AX=errno */
- 
 
 166 
    jc DONE
- 
 
 167 
    mov [res], cx
- 
 
 168 
    DONE:
- 
 
 169 
  }
- 
 
 170 
  return(res);
- 
 
 171 
}
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 172