util.h

/*
 * This file is part of hx - a hex editor for the terminal.
 *
 * Copyright (c) 2016 Kevin Pors. See LICENSE for details.
 */

#ifndef HX_UTIL_H
#define HX_UTIL_H

#include <stdbool.h>
#include <termios.h>

// Key enumeration, returned by read_key().
enum key_codes {
	KEY_NULL      = 0,
	KEY_CTRL_B    = 0x02,
	KEY_CTRL_D    = 0x04,
	KEY_CTRL_F    = 0x06,
	KEY_CTRL_H    = 0x08,
	KEY_CTRL_Q    = 0x11, // DC1, to exit the program.
	KEY_CTRL_R    = 0x12, // DC2, to redo an action.
	KEY_CTRL_S    = 0x13, // DC3, to save the current buffer.
	KEY_CTRL_U    = 0x15,
	KEY_ESC       = 0x1b, // ESC, for things like keys up, down, left, right, delete, ...
	KEY_ENTER     = 0x0d,
	KEY_BACKSPACE = 0x7f,

	// 'Virtual keys', i.e. not corresponding to terminal escape sequences
	// or any other ANSI stuff. Merely to identify keys returned by read_key().
	KEY_UP      = 1000, // [A
	KEY_DOWN,           // [B
	KEY_RIGHT,          // [C
	KEY_LEFT,           // [D
	KEY_DEL,            // . = 1b, [ = 5b, 3 = 33, ~ = 7e,
	KEY_HOME,           // [H
	KEY_END,            // [F
	KEY_PAGEUP,         // ??
	KEY_PAGEDOWN,       // ??
};

// Errors which may be returned by parse_search_string.
enum parse_errors {
	PARSE_SUCCESS,
	PARSE_INCOMPLETE_BACKSLASH,  // "...\"
	PARSE_INCOMPLETE_HEX,        // "...\x" or "...\xA"
	PARSE_INVALID_HEX,           // "...\xXY..." and X or Y not in [a-zA-Z0-9]
	PARSE_INVALID_ESCAPE,        // "...\a..." and a is not '\' or 'x'
};

/*
 * Saves the current terminal state (the contents) so it can be restored
 * later, when hx exits. This behaviour is like any other terminal GUI
 * application. Currently, this writes the 'smcup' terminal capability.
 * I'm unsure how this will behave when the cap is not available.
 */
void term_state_save();

/*
 * This restores the previously saved terminal contents. This will write
 * the termcap `rmcup' to stdout. Like term_state_save, I'm not sure how
 * this will behave when the cap is unavailable.
 */
void term_state_restore();

void enable_raw_mode();
void disable_raw_mode();
void clear_screen();
int  read_key();
int  hex2bin(const char* s);
bool get_window_size(int* rows, int* cols);

/*
 * Returns true when the given char can be successfully parsed as a positive
 * integer, or return false if otherwise.
 */
bool is_pos_num(const char* s);

/*
 * Returns true when the given string is a valid hexadecimal string, or false
 * if othwerise.
 */
bool is_hex(const char* s);

int hex2int(const char* s);

/*
 * Clamps the given integer i to the given min or max. If i is smaller than
 * min, min is returned. If i is larger than max, max is returned. In all
 * other cases, i is returned.
 */
int clampi(int i, int min, int max);

/*
 * Parses a string to an integer and returns it. In case of errors, the default
 * `def' will be returned. When the `min' > parsed_value > `max', then the
 * default `def' will also be returned.
 *
 * XXX: probably return some error indicator instead, and exit with a message?
 */
int str2int(const char* s, int min, int max, int def);

#endif // HX_UTIL_H