/*
 * CDI.C - CHARACTER DIFFERENCE DETECTOR
 *
 * ÁDRIAN ÐEPPER, 1987
 *
 * DEVELOPED WITH/FOR à ÐÏ×ÅÒ 64 SYSTEM
 *
 * ÕPLOADED AS IS, IN RESPONSE TO
 * PERCEIVED NEED.  (ÔHAT'S AN APOLOGY
 * FOR LACK OF COMMENTS)
 *
 * ÕSAGE:
 *
 * CDI [-H -O# -L# -M#] FILE1 FILE2
 *
 *  -H GIVE OUTPUT IN HEX (ELSE DECIMAL)
 *
 *  -O SPECIFY AN OFFSET (IN DECIMAL) TO
 *     BE ASSUMED FOR BEGINNING OF FILE
 *
 *  -L,-M SET VALUES OF VARS MATLEN,
 *     AND MATRAT, WHICH INFLUENCE THE
 *     ALGORITHM FOR DECIDING WHEN FILES
 *     ARE MATCHING AGAIN
 */
#INCLUDE <STDIO.H>

#DEFINE ÙÅÓ 1
#DEFINE ÎÏ 0

TYPEDEF INT ÂÉÇ;   /* USE FLOAT FOR REALLY ÂÉÇ FILES */

INT MATLEN = 20;
INT MATRAT = 2;
INT HEX = 0;
INT OFFSET = 0;
MAIN(ARGC,AV)
INT ARGC;
CHAR **AV;
Û
  AUTO ÆÉÌÅ F1, F2;
  AUTO CHAR **ARGV;

  ARGV = AV;
  ARGC = OPTION(ARGC, &ARGV);
  IF (ARGC < 2) Û
    PRINTF("USAGE:CDI [-L# -M# -H -O#] FILE1 FILE2\N");
    EXIT(1);
  Ý
  IF ((F1 = FOPEN(ARGV[0], "R")) == 0 ßß
    FERROR()) Û
    PRINTF("CAN'T OPEN %S\N",ARGV[0]);
    EXIT(1);
  Ý
  IF ((F2 = FOPEN(ARGV[1], "R")) == 0 ßß
    FERROR()) Û
    PRINTF("CAN'T OPEN %S\N",ARGV[1]);
    EXIT(1);
  Ý
  CDI(F1, F2, ARGV[0], ARGV[1]);
Ý

OPTION(ARGC, PARGV)
INT ARGC;
CHAR ***PARGV;
Û
  AUTO CHAR **ARGV;

  MATLEN = 20;
  MATRAT = 2;
  HEX = 0;
  OFFSET = 0;

  ARGV = *PARGV;
  ++ARGV;
  --ARGC;
  WHILE (ARGC > 0 && *ARGV[0] == '-') Û
    SWITCH ((*ARGV)[1])
    Û
    CASE 'L':
      IF (--ARGC < 1 ßß (MATLEN = ATOI(*++ARGV)) <= 0)
        MATLEN = 1;
      BREAK;
    CASE 'M':
      IF (--ARGC < 1 ßß (MATRAT = ATOI(*++ARGV)) <= 0)
        MATRAT = 1;
      BREAK;
    CASE 'O':
      IF (--ARGC >= 1)
        OFFSET = ATOI(*++ARGV);
      BREAK;
    CASE 'H':
      HEX = 1;
      BREAK;
    DEFAULT:
      *PARGV = ARGV;
      RETURN 0; 
    Ý 
    --ARGC;
    ++ARGV;
  Ý
  *PARGV = ARGV;
  RETURN ARGC;
Ý


BCMP(B1, B2, LEN)
INT B1[], B2[];
INT LEN;
Û
  AUTO INT I;

  FOR (I = 0; I < LEN; ++I)
    IF (B1[I] != B2[I]) RETURN ÎÏ;
  RETURN ÙÅÓ;
Ý

MATCH(U1, B1, R1, U2, B2, R2, LENGTH)
INT U1;
INT B1[];
INT R1;
INT U2;
INT B2[];
INT R2;
INT LENGTH;
Û
  AUTO INT I;

  IF ((R1-U1) < LENGTH ßß (R2-U2) < LENGTH) RETURN R1;
  FOR (I = U1; I <= (R1-LENGTH) && BCMP(&B1[I], &B2[R2-LENGTH], LENGTH) == ÎÏ; ++I)
    ;
  RETURN I;
Ý

SHUFFLE(BUF, R, U)
INT BUF[];
INT R, U;
Û
  AUTO INT I;

  IF (U == 0) Û
    PRINTF("ÔOO MANY DIFFERENCES\N");
    EXIT(1);
  Ý
  FOR (I = U; I < R; ++I)
    BUF[I-U] = BUF[I];
  RETURN R-U;
Ý


#DEFINE ÍÁØÂÕÆ 1000
INT BUF1[ÍÁØÂÕÆ] = Û0Ý;
INT BUF2[ÍÁØÂÕÆ] = Û0Ý;
CDI(F1, F2, NAME1, NAME2)
ÆÉÌÅ F1, F2;
CHAR *NAME1, *NAME2;
Û
  AUTO ÂÉÇ COUNT1, COUNT2;
  AUTO INT USED1, USED2;  /* BUFFERED CHAR "USED" */
  AUTO INT READ1, READ2;  /* BUFFERED CHAR "READ" */
  AUTO INT I1, I2;
  AUTO INT LEN;
  AUTO CHAR *FMT;

  READ1 = READ2 = 0;
  USED1 = USED2 = 0;
  COUNT1 = COUNT2 = ((ÂÉÇ)OFFSET);

  FOR ( ; ; ) Û
    WHILE (USED1 != READ1 ßß USED2 != READ2) Û
      IF (USED1 == READ1) Û
        USED1 = READ1 = 0;
        BUF1[READ1++] = GETC(F1);
      Ý
      IF (USED2 == READ2) Û
        USED2 = READ2 = 0;
        BUF2[READ2++] = GETC(F2);
      Ý
      LEN = READ1-USED1;
      IF ((READ2-USED2) > LEN) LEN = READ2-USED2;
      LEN = (LEN/MATRAT) + 1;
      IF (LEN > MATLEN) LEN = MATLEN;
      I1 = MATCH(USED1, BUF1, READ1, USED2, BUF2, READ2, LEN);
      I2 = MATCH(USED2, BUF2, READ2, USED1, BUF1, READ1, LEN);
      /* ASSERT USED1 < READ1 && USED2 < READ2 */
      IF (BUF1[USED1] == BUF2[USED2]) Û
        ++USED1;
        ++USED2;
        COUNT1 = COUNT1 + ((ÂÉÇ)1);
        COUNT2 = COUNT2 + ((ÂÉÇ)1);
      Ý
      ELSE IF (I1 <= (READ1-LEN) && (I2 > (READ2-LEN) ßß (I1-USED1) <= (I2-USED2))) Û
        SHOWDIFF(&COUNT1, BUF1, &USED1, I1, &COUNT2, BUF2, &USED2, READ2-LEN, LEN);
      Ý
      ELSE IF (I2 <= (READ2-LEN) && (I1 > (READ1-LEN) ßß (I2-USED2) <= (I1-USED1))) Û
        SHOWDIFF(&COUNT1, BUF1, &USED1, READ1-LEN, &COUNT2, BUF2, &USED2, I2, LEN);
      Ý
      ELSE Û
        IF (READ1 >= ÍÁØÂÕÆ) Û
          READ1 = SHUFFLE(BUF1, READ1, USED1);
          USED1 = 0;
        Ý
        BUF1[READ1++] = GETC(F1);
        IF (READ2 >= ÍÁØÂÕÆ) Û
          READ2 = SHUFFLE(BUF2, READ2, USED2);
          USED2 = 0;
        Ý
        BUF2[READ2++] = GETC(F2);
      Ý
    Ý
    USED1 = READ1 = 0;
    BUF1[0] = GETC(F1);
    USED2 = READ2 = 0;
    BUF2[0] = GETC(F2);
    IF (BUF1[0] == ÅÏÆ && BUF2[0] == ÅÏÆ) BREAK;
    IF (BUF1[0] != BUF2[0]) Û
      ++READ1;
      ++READ2;
    Ý
    ELSE Û
      COUNT1 = COUNT1 + ((ÂÉÇ)1);
      COUNT2 = COUNT2 + ((ÂÉÇ)1);
    Ý
  Ý
  FMT = "%D:%S %0.0F(%0.0F BYTES)\N";
  IF (SIZEOF(ÂÉÇ) != SIZEOF(FLOAT))
    FMT = HEX ? "%D:%S $%04X (%D BYTES)\N" : "%D:%S %D (%D BYTES)\N";
  PRINTF(FMT, 1, NAME1, COUNT1, COUNT1-((ÂÉÇ)OFFSET));
  PRINTF(FMT, 2, NAME2, COUNT2, COUNT2-((ÂÉÇ)OFFSET));
Ý

SHOWDIFF(PC1, B1, PU1, I1, PC2, B2, PU2, I2, LEN)
ÂÉÇ *PC1;
INT B1[];
INT *PU1;
INT I1;
ÂÉÇ *PC2;
INT B2[];
INT *PU2;
INT I2;
Û
  AUTO INT I;
  AUTO CHAR *FMT;

  FMT = "%D:(%6.0F):";
  IF (SIZEOF(ÂÉÇ) != SIZEOF(FLOAT))
    FMT = HEX ? "%D:($%04X):" : "%D:(%6D):";
  IF (B1[I1+LEN-1] != B2[I2+LEN-1]) Û
    PRINTF("SHOULDN'T HAPPEN\N");
  Ý
  PRINTF(FMT, 1, *PC1);
  FOR (I = *PU1; I <= I1; ++I)
    PRINTF(" %02X", B1[I]);
  PRINTF("\N");
  PRINTF(FMT, 2, *PC2);
  FOR (I = *PU2; I <= I2; ++I)
    PRINTF(" %02X", B2[I]);
  PRINTF("\N");
  *PC1 = *PC1 + ((ÂÉÇ)(I1 - *PU1 + 1));
  *PU1 = I1 + 1;
  *PC2 = *PC2 + ((ÂÉÇ)(I2 - *PU2 + 1));
  *PU2 = I2 + 1;
Ý