morse -- Morse encoder and decoder C library

Encode text messages into Morse code and decode them using a binary search tree (AVL tree) structure. It supports customizable encoding options, including separators and prosigns, to facilitate Morse code transmission and decoding.

Features

• Initialize and destroy Morse code binary trees.
• Encode strings into Morse code with configurable options.
• Support for Morse separators (spaces between characters and words).
• Support for prosigns such as "SK", "AR", and "CT" for special transmission signals.
• Uses an AVL tree for efficient character lookup and encoding based on Morse priority.

Data structure

• morse_tree_td. An AVL binary search tree representing Morse code characters and their encoding.

Usage

Initialization

Create a new Morse code tree:

morse_tree_td *morse_tree = morse_init();
if (morse_tree == NULL) {
    /* Handle error */
}

Encoding a message

Encode an ASCII string into Morse code:

char encoded[MORSE_MESSAGE_MAX_LENGTH];
const char *inpupt = "Hello, World";

if (morse_encode(morse_tree, morse_message, input,
             MORSE_USE_SEPARATORS | MORSE_USE_PROSIGNS) != 0) {
    fprintf(stderr, "Encoding failed\n");
    morse_destroy(morse_tree);
    return -1;
}
printf("Encoded: %s\n", encoded);

Decoding a message

Decode a Morse code string into ASCII:

char decoded[MORSE_MESSAGE_MAX_LENGTH + 1] = {'\0'};
const char *input = "...   ---   ...       .-   .-.";   /* "SOS AR" */

if (morse_decode(morse_tree, decoded, input, MORSE_USE_SEPARATORS) != 0) {
    fprintf(stderr, "Decoding failed\n");
    morse_destroy(morse_tree);
    return -1;
}
printf("Decoded: '%s'\n", decoded);

Flags

• MORSE_NO_FLAGS. No special features.
• MORSE_USE_SEPARATORS. Use spaces to separate characters and words.
• MORSE_USE_PROSIGNS. Include prosigns like "AR", "SK", "CT" at start and end.

Cleanup

Destroy the Morse tree when done:

morse_destroy(morse_tree);

Constants and macros

• MORSE_MAX_NODES. Maximum number of nodes in the Morse tree.
• MORSE_MESSAGE_MAX_LENGTH. Maximum length of the Morse message.
• MORSE_DIT / MORSE_DAH. Representations of dot ("dit") and dash ("dah").
• Separator constants. Define spacing between characters and words.
• Prosigns. Special Morse signals such as "AR", "SK", "CT".

Notes

• The Morse tree is organized according to Morse code priority, stored as an AVL tree for efficient encoding.
• Supports encoding of alphabetic characters, digits, and some punctuation.
• Punctuation characters are ignored in tree construction but influence insertion order.

License

• ISC License
• Copyright (c) 2025, J. A. Corbal
• Read the file LICENSE for more details