42sh/src/lexer/lexer.c

#include "lexer.h"

#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#include "io_backend/io_backend.h"

static char *end_last_token;
static ssize_t remaining_chars;

char *new_token(char *begin, ssize_t size)
{
    char *res = calloc(size + 1, sizeof(char));
    if (res == NULL)
        return NULL;
    strncpy(res, begin, size);
    return res;
}

char *stream_init(void)
{
    char *stream;

    if (remaining_chars == 0)
    {
        remaining_chars = stream_read(&stream);
    }
    else
    {
        stream = end_last_token;
    }

    return stream;
}

char *get_token(void)
{
    char *stream = stream_init();

    bool inquotes = false;
    ssize_t i = 0;

    while (i < remaining_chars)
    {
        switch (stream[i])
        {
        case '\'':
            inquotes = !inquotes;
            break;

        case ' ' | '\n' | '\t':
            if (inquotes)
                break;
            else
            {
                // token creation
                // skip blank char
                // exit from loop
                char *token = new_token(stream, i);
                return token;
            }
        default:
            break;
        }
        i++;
    }

    remaining_chars -= i;
    return NULL;
}