54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
#include <stdio.h>
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extern void printx(int);
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extern void printd(int);
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int myprintf(const char* format, ...) {
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int* varArg = (int*)(&format + 1);
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int varArgIndex = 0; // Offset by one
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int i = 0;
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char* varArgChar = (char*)(varArg);
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char** varArgStr = (char**)(varArg);
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int* varArgInt = (int*)(varArg);
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while (format[i] != '\0') {
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if (format[i] == '%') {
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i++;
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if (format[i] == 'c') {
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// print var arg char.
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putchar(varArgChar[varArgIndex]);
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varArgIndex++;
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} else if (format[i] == 's') {
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// loop through each char of string in var arg.
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int j = 0;
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while (varArgStr[varArgIndex][j] != '\0') {
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putchar(varArgStr[varArgIndex][j]);
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j++;
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}
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varArgIndex++;
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} else if (format[i] == 'x') {
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// print the var arg's value in hex through assembly.
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printx(varArgInt[varArgIndex]);
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varArgIndex++;
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} else if (format[i] == 'd') {
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// print the var arg's value in decimal through assembly.
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printd(varArgInt[varArgIndex]);
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varArgIndex++;
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} else if (format[i] == '%') {
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// print an escaped percent symbol.
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putchar('%');
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} else {
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printf("An invalid flag was encountered: %c.", format[i]);
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return 1;
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}
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} else {
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putchar(format[i]);
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}
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i++;
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}
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return 0;
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}
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