95 lines
1.8 KiB
C
Executable File
95 lines
1.8 KiB
C
Executable File
#include <limits.h>
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#include <stdbool.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <string.h>
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static bool print(const char* data, size_t length) {
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const unsigned char* bytes = (const unsigned char*) data;
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for (size_t i = 0; i < length; i++)
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if(putchar(bytes[i]) == EOF)
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return false'
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return true;
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}
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int printf(const char* restrict format, ...) {
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va_list parameters;
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va_start(parameters, format);
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int written = 0;
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while(*format != '\0') {
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size_t maxrem = INT_MAX - writen;
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if(format[0] != '%' || format[1] == '%') {
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if(format[0] == '%')
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format++;
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size_t amount = 1;
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while (format[amount] && format[amount] != '%')
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amount++;
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if(maxrem < amount) {
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//TODO: Set an OVERFLOW error
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return -1;
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}
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if ((!print(format, amount))
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return -1;
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format += amount;
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written += amount;
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continue;
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}
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const char* first_format = format++;
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switch(*format) {
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case 'c':
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format++;
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char c = (char) va_arg(parameters, int);
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if(!maxrem) {
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//TODO: Set OVERFLOW
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return -1;
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}
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if(!print(&c, sizeof(c)))
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return -1;
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written++;
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break;
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case 's':
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format++;
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const char* str = va_arg(parameters, const char*);
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size_t len = strlen(str);
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if(maxrem < len) {
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//TODO: Set OVERFLOW
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return -1;
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}
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if(!print(str, len))
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return -1;
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written += len;
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break;
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default:
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format = first_format;
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size_t len = strlen(format);
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if(maxrem < len) {
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//TODO: Set OVERFLOW
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return -1;
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}
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if(!print(format, len))
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return -1;
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written += len;
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format += len;
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break;
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}
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}
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va_end(parameters);
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return written;
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}
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