// SPDX-License-Identifier: MIT

#include "util.hpp"

#include <stdint.h>
#include <stdio.h>

#include "helpers.hpp" // assume

bool isNewline(int c) {
	return c == '\r' || c == '\n';
}

bool isBlankSpace(int c) {
	return c == ' ' || c == '\t';
}

bool isWhitespace(int c) {
	return isBlankSpace(c) || isNewline(c);
}

bool isPrintable(int c) {
	return c >= ' ' && c <= '~';
}

bool isLetter(int c) {
	return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
}

bool isDigit(int c) {
	return c >= '0' && c <= '9';
}

bool isOctDigit(int c) {
	return c >= '0' && c <= '7';
}

bool isHexDigit(int c) {
	return isDigit(c) || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f');
}

bool isAlphanumeric(int c) {
	return isLetter(c) || isDigit(c);
}

bool startsIdentifier(int c) {
	// This returns false for anonymous labels, which internally start with a '!',
	// and for section fragment literal labels, which internally start with a '$'.
	return isLetter(c) || c == '.' || c == '_';
}

bool continuesIdentifier(int c) {
	return startsIdentifier(c) || isDigit(c) || c == '#' || c == '$' || c == '@';
}

uint8_t parseHexDigit(int c) {
	if (c >= 'A' && c <= 'F') {
		return c - 'A' + 10;
	} else if (c >= 'a' && c <= 'f') {
		return c - 'a' + 10;
	} else {
		assume(isDigit(c));
		return c - '0';
	}
}

char const *printChar(int c) {
	// "'A'" + '\0': 4 bytes
	// "'\\n'" + '\0': 5 bytes
	// "0xFF" + '\0': 5 bytes
	static char buf[5];

	if (c == EOF) {
		return "EOF";
	}

	// Handle printable ASCII characters
	if (isPrintable(c)) {
		buf[0] = '\'';
		buf[1] = c;
		buf[2] = '\'';
		buf[3] = '\0';
		return buf;
	}

	switch (c) {
	case '\n':
		buf[2] = 'n';
		break;
	case '\r':
		buf[2] = 'r';
		break;
	case '\t':
		buf[2] = 't';
		break;
	case '\0':
		buf[2] = '0';
		break;

	default: // Print as hex
		buf[0] = '0';
		buf[1] = 'x';
		snprintf(&buf[2], 3, "%02hhX", static_cast<uint8_t>(c)); // includes the '\0'
		return buf;
	}
	buf[0] = '\'';
	buf[1] = '\\';
	buf[3] = '\'';
	buf[4] = '\0';
	return buf;
}