#include #include /* #include */ #include #include /* returns 1 for true, adhering to suckless */ static int print(const char* data, size_t length) { const unsigned char* bytes = (const unsigned char*) data; for (size_t i = 0; i < length; i++) { if (putchar(bytes[i]) == EOF) { return 0; } } return 1; } /* todo: set errno to eoverflow for some cases in which errno should not be used */ int printf(const char* restrict format, ...) { va_list parameters; va_start(parameters, format); int written = 0; while (*format != '\0') { size_t maxrem = INT_MAX - written; if (format[0] != '%' || format[1] == '%') { if (format[0] == '%') format++; size_t amount = 1; while (format[amount] && format[amount] != '%') amount++; if (maxrem < amount) { return -1; } if (!print(format, amount)) return -1; format += amount; written += amount; continue; } const char* format_begun_at = format++; if (*format == 'c') { format++; char c = (char) va_arg(parameters, int /* char promotes to int */); if (!maxrem) { return -1; } if (!print(&c, sizeof(c))) { return -1; } written++; } else if (*format == 's') { format++; const char* str = va_arg(parameters, const char*); size_t len = strlen(str); if (maxrem < len) { return -1; } if (!print(str, len)) { return -1; } written += len; } else { format = format_begun_at; size_t len = strlen(format); if (maxrem < len) { return -1; } if (!print(format, len)) { return -1; } written += len; format += len; } } va_end(parameters); return written; } /* todo: Implement stdio and the write system call. */ int putchar(int ic) { return ic; } int puts(const char* string) { return printf("%s\n", string); }