Initial data commit

Task/Calendar---for-REAL-programmers/C/calendar---for-real-programmers.c

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+/* UPPER CASE ONLY VERSION OF THE ORIGINAL CALENDAR.C, CHANGES MOSTLY TO AVOID NEEDING #INCLUDES */
+/* ERROR MESSAGES GO TO STDOUT TO SLIGHTLY SIMPLIFY THE I/O HANDLING                             */
+/* WHEN COMPILING THIS, THE COMMAND LINE SHOULD SPECIFY -D OPTIONS FOR THE FOLLOWING WORDS:      */
+/*    STRUCT, VOID, INT, CHAR, CONST, MAIN, IF, ELSE, WHILE, FOR, DO, BREAK, RETURN, PUTCHAR     */
+/* THE VALUE OF EACH MACRO SHOULD BE THE WORD IN LOWER-CASE                                      */
+
+INT PUTCHAR(INT);
+
+INT WIDTH = 80, YEAR = 1969;
+INT COLS, LEAD, GAP;
+
+CONST CHAR *WDAYS[] = { "SU", "MO", "TU", "WE", "TH", "FR", "SA" };
+STRUCT MONTHS {
+    CONST CHAR *NAME;
+    INT DAYS, START_WDAY, AT;
+} MONTHS[12] = {
+    { "JANUARY",    31, 0, 0 },
+    { "FEBRUARY",    28, 0, 0 },
+    { "MARCH",    31, 0, 0 },
+    { "APRIL",    30, 0, 0 },
+    { "MAY",    31, 0, 0 },
+    { "JUNE",    30, 0, 0 },
+    { "JULY",    31, 0, 0 },
+    { "AUGUST",    31, 0, 0 },
+    { "SEPTEMBER",    30, 0, 0 },
+    { "OCTOBER",    31, 0, 0 },
+    { "NOVEMBER",    30, 0, 0 },
+    { "DECEMBER",    31, 0, 0 }
+};
+
+VOID SPACE(INT N) { WHILE (N-- > 0) PUTCHAR(' '); }
+VOID PRINT(CONST CHAR * S){ WHILE (*S != '\0') { PUTCHAR(*S++); } }
+INT  STRLEN(CONST CHAR * S)
+{
+   INT L = 0;
+   WHILE (*S++ != '\0') { L ++; };
+RETURN L;
+}
+INT ATOI(CONST CHAR * S)
+{
+    INT I = 0;
+    INT SIGN = 1;
+    CHAR C;
+    WHILE ((C = *S++) != '\0') {
+        IF (C == '-')
+            SIGN *= -1;
+        ELSE {
+            I *= 10;
+            I += (C - '0');
+        }
+    }
+RETURN I * SIGN;
+}
+
+VOID INIT_MONTHS(VOID)
+{
+    INT I;
+
+    IF ((!(YEAR % 4) && (YEAR % 100)) || !(YEAR % 400))
+        MONTHS[1].DAYS = 29;
+
+    YEAR--;
+    MONTHS[0].START_WDAY
+        = (YEAR * 365 + YEAR/4 - YEAR/100 + YEAR/400 + 1) % 7;
+
+    FOR (I = 1; I < 12; I++)
+        MONTHS[I].START_WDAY =
+            (MONTHS[I-1].START_WDAY + MONTHS[I-1].DAYS) % 7;
+
+    COLS = (WIDTH + 2) / 22;
+    WHILE (12 % COLS) COLS--;
+    GAP = COLS - 1 ? (WIDTH - 20 * COLS) / (COLS - 1) : 0;
+    IF (GAP > 4) GAP = 4;
+    LEAD = (WIDTH - (20 + GAP) * COLS + GAP + 1) / 2;
+        YEAR++;
+}
+
+VOID PRINT_ROW(INT ROW)
+{
+    INT C, I, FROM = ROW * COLS, TO = FROM + COLS;
+    SPACE(LEAD);
+    FOR (C = FROM; C < TO; C++) {
+        I = STRLEN(MONTHS[C].NAME);
+        SPACE((20 - I)/2);
+        PRINT(MONTHS[C].NAME);
+        SPACE(20 - I - (20 - I)/2 + ((C == TO - 1) ? 0 : GAP));
+    }
+    PUTCHAR('\012');
+
+    SPACE(LEAD);
+    FOR (C = FROM; C < TO; C++) {
+        FOR (I = 0; I < 7; I++) {
+            PRINT(WDAYS[I]);
+            PRINT(I == 6 ? "" : " ");
+        }
+        IF (C < TO - 1) SPACE(GAP);
+        ELSE PUTCHAR('\012');
+    }
+
+    WHILE (1) {
+        FOR (C = FROM; C < TO; C++)
+            IF (MONTHS[C].AT < MONTHS[C].DAYS) BREAK;
+        IF (C == TO) BREAK;
+
+        SPACE(LEAD);
+        FOR (C = FROM; C < TO; C++) {
+            FOR (I = 0; I < MONTHS[C].START_WDAY; I++) SPACE(3);
+            WHILE(I++ < 7 && MONTHS[C].AT < MONTHS[C].DAYS) {
+                INT MM = ++MONTHS[C].AT;
+                PUTCHAR((MM < 10) ? ' ' : '0' + (MM /10));
+                PUTCHAR('0' + (MM %10));
+                IF (I < 7 || C < TO - 1) PUTCHAR(' ');
+            }
+            WHILE (I++ <= 7 && C < TO - 1) SPACE(3);
+            IF (C < TO - 1) SPACE(GAP - 1);
+            MONTHS[C].START_WDAY = 0;
+        }
+        PUTCHAR('\012');
+    }
+    PUTCHAR('\012');
+}
+
+VOID PRINT_YEAR(VOID)
+{
+    INT Y = YEAR;
+    INT ROW;
+    CHAR BUF[32];
+    CHAR * B = &(BUF[31]);
+    *B-- = '\0';
+    DO {
+        *B-- = '0' + (Y % 10);
+        Y /= 10;
+    } WHILE (Y > 0);
+    B++;
+    SPACE((WIDTH - STRLEN(B)) / 2);
+    PRINT(B);PUTCHAR('\012');PUTCHAR('\012');
+    FOR (ROW = 0; ROW * COLS < 12; ROW++)
+        PRINT_ROW(ROW);
+}
+
+INT MAIN(INT C, CHAR **V)
+{
+    INT I, YEAR_SET = 0, RESULT = 0;
+    FOR (I = 1; I < C && RESULT == 0; I++) {
+        IF (V[I][0] == '-' && V[I][1] == 'W' && V[I][2] == '\0') {
+            IF (++I == C || (WIDTH = ATOI(V[I])) < 20)
+                RESULT = 1;
+        } ELSE IF (!YEAR_SET) {
+            YEAR = ATOI(V[I]);
+            IF (YEAR <= 0)
+                YEAR = 1969;
+            YEAR_SET = 1;
+        } ELSE
+            RESULT = 1;
+    }
+
+    IF (RESULT == 0) {
+        INIT_MONTHS();
+        PRINT_YEAR();
+    } ELSE {
+        PRINT("BAD ARGS\012USAGE: ");
+        PRINT(V[0]);
+        PRINT(" YEAR [-W WIDTH (>= 20)]\012");
+    }
+RETURN RESULT;
+}