input.c

/*
 * input.c
 *
 * Input routines
 *
 */

#include "ztypes.h"

/* Statically defined word separator list */

static const char *separators = " \t\n\f.,?";
static zword_t dictionary_offset = 0;
static short dictionary_size = 0;
static unsigned int entry_size = 0;

#ifdef __STDC__
static void tokenise_line (zword_t, zword_t, zword_t, zword_t);
static const char *next_token (const char *, const char **, int *, const char *);
static zword_t find_word (int, const char *, long);
#else
static void tokenise_line ();
static const char *next_token ();
static zword_t find_word ();
#endif

/*
 * read_character
 *
 * Read one character with optional timeout
 *
 *    argv[0] = # of characters to read (only 1 supported currently)
 *    argv[1] = timeout value in seconds (optional)
 *    argv[2] = timeout action routine (optional)
 *
 */

#ifdef __STDC__
void read_character (int argc, zword_t *argv)
#else
void read_character (argc, argv)
int argc;
zword_t *argv;
#endif
{
    int c;
    zword_t arg_list[2];

    /* Supply default parameters */

    if (argc < 3)
        argv[2] = 0;
    if (argc < 2)
        argv[1] = 0;

    /* Flush any buffered output before read */

    flush_buffer (FALSE);

    /* Reset line count */

    lines_written = 0;

    /* If more than one characters was asked for then fail the call */

    if (argv[0] != 1)

        c = 0;

    else {

        if ((c = playback_key ()) == -1) {

            /* Setup the timeout routine argument list */

            arg_list[0] = argv[2];
            arg_list[1] = argv[1];

            /* Read a character with a timeout. If the input timed out then
               call the timeout action routine. If the return status from the
               timeout routine was 0 then try to read a character again */

            do {
                c = input_character ((int) argv[1]);
            } while (c == -1 && call (2, arg_list, ASYNC) == 0);

            /* Fail call if input timed out */

            if (c == -1)
                c = 0;
            else
                record_key (c);
        }
    }

    store_operand (c);

}/* read_character */

/*
 * read_line
 *
 * Read a line of input with optional timeout.
 *
 *    argv[0] = character buffer address
 *    argv[1] = token buffer address
 *    argv[2] = timeout value in seconds (optional)
 *    argv[3] = timeout action routine (optional)
 *
 */

#ifdef __STDC__
void read_line (int argc, zword_t *argv)
#else
void read_line (argc, argv)
int argc;
zword_t *argv;
#endif
{
    int i, in_size, out_size, terminator;
    char *cbuf, *buffer;

    /* Supply default parameters */

    if (argc < 4)
        argv[3] = 0;
    if (argc < 3)
        argv[2] = 0;
    if (argc < 2)
        argv[1] = 0;

    /* Refresh status line */

    if (h_type < V4)
        display_status_line ();

    /* Flush any buffered output before read */

    flush_buffer (TRUE);

    /* Reset line count */

    lines_written = 0;

    /* Initialise character pointer and initial read size */

    cbuf = (char *) &datap[argv[0]];
    in_size = (h_type > V4) ? cbuf[1] : 0;

    /* Read the line then script and record it */

    terminator = get_line (cbuf, argv[2], argv[3]);
    script_line ((h_type > V4) ? &cbuf[2] : &cbuf[1]);
    record_line ((h_type > V4) ? &cbuf[2] : &cbuf[1]);

    /* Convert new text in line to lowercase */

    if (h_type > V4) {
        buffer = &cbuf[2];
        out_size = cbuf[1];
    } else {
        buffer = &cbuf[1];
        out_size = strlen (buffer);
    }

    if (out_size > in_size)
        for (i = in_size; i < out_size; i++)
            if ( isupper (buffer[i]) )
                buffer[i] = (char) tolower (buffer[i]);

    /* Tokenise the line, if a token buffer is present */

    if (argv[1])
        tokenise_line (argv[0], argv[1], h_words_offset, 0);

    /* Return the line terminator */

    if (h_type > V4)
        store_operand ((zword_t) terminator);

}/* read_line */

/*
 * get_line
 *
 * Read a line of input and lower case it.
 *
 */

#ifdef __STDC__
int get_line (char *cbuf, zword_t timeout, zword_t action_routine)
#else
int get_line (cbuf, timeout, action_routine)
char *cbuf;
zword_t timeout;
zword_t action_routine;
#endif
{
    char *buffer;
    int buflen, read_size, status, c;
    zword_t arg_list[2];

    /* Set maximum buffer size to width of screen minus any
       right margin and 1 character for a terminating NULL */

    buflen = (screen_cols > 127) ? 127 : screen_cols;
    buflen -= right_margin + 1;
    if ((int) cbuf[0] <= buflen)
        buflen = cbuf[0];

    /* Set read size and start of read buffer. The buffer may already be
       primed with same text in V5 games. The Z-code will have already
       displayed the text so we don't have to do that */

    if (h_type > V4) {
        read_size = cbuf[1];
        buffer = &cbuf[2];
    } else {
        read_size = 0;
        buffer = &cbuf[1];
    }

    /* Try to read input from command file */

    c = playback_line (buflen, buffer, &read_size);

    if (c == -1) {

        /* Setup the timeout routine argument list */

        arg_list[0] = action_routine;
        arg_list[1] = timeout;

        /* Read a line with a timeout. If the input timed out then
           call the timeout action routine. If the return status from the
           timeout routine was 0 then try to read the line again */

        do {
            c = input_line (buflen, buffer, timeout, &read_size);
            status = 0;
        } while (c == -1 && (status = call (2, arg_list, ASYNC)) == 0);

        /* Throw away any input if timeout returns success */

        if (status)
            read_size = 0;

    }

    /* Zero terminate line */

    buffer[read_size] = '\0';

    if (h_type > V4)
        cbuf[1] = (char) read_size;

    return (c);

}/* get_line */

/*
 * tokenise_line
 *
 * Convert a typed input line into tokens. The token buffer needs some
 * additional explanation. The first byte is the maximum number of tokens
 * allowed. The second byte is set to the actual number of token read. Each
 * token is composed of 3 fields. The first (word) field contains the word
 * offset in the dictionary, the second (byte) field contains the token length,
 * and the third (byte) field contains the start offset of the token in the
 * character buffer.
 *
 */

#ifdef __STDC__
static void tokenise_line (zword_t char_buf, zword_t token_buf, zword_t dictionary, zword_t flag)
#else
static void tokenise_line (char_buf, token_buf, dictionary, flag)
zword_t char_buf;
zword_t token_buf;
zword_t dictionary;
zword_t flag;
#endif
{
    int i, count, words, token_length;
    long word_index, chop = 0;
    char *cbuf, *tbuf, *tp;
    const char *cp, *token;
    char punctuation[16];
    zword_t word;

    /* Initialise character and token buffer pointers */

    cbuf = (char *) &datap[char_buf];
    tbuf = (char *) &datap[token_buf];

    /* Initialise word count and pointers */

    words = 0;
    cp = (h_type > V4) ? cbuf + 2 : cbuf + 1;
    tp = tbuf + 2;

    /* Initialise dictionary */

    count = get_byte (dictionary++);
    for (i = 0; i < count; i++)
        punctuation[i] = get_byte (dictionary++);
    punctuation[i] = '\0';
    entry_size = get_byte (dictionary++);
    dictionary_size = (short) get_word (dictionary);
    dictionary_offset = dictionary + 2;

    /* Calculate the binary chop start position */

    if (dictionary_size > 0) {
        word_index = dictionary_size / 2;
        chop = 1;
        do
            chop *= 2;
        while (word_index /= 2);
    }

    /* Tokenise the line */

    do {

        /* Skip to next token */

        cp = next_token (cp, &token, &token_length, punctuation);
        if (token_length)

            /* If still space in token buffer then store word */

            if (words <= tbuf[0]) {

                /* Get the word offset from the dictionary */

                word = find_word (token_length, token, chop);

                /* Store the dictionary offset, token length and offset */

                if (word || flag == 0) {
                    tp[0] = (char) (word >> 8);
                    tp[1] = (char) (word & 0xff);
                }
                tp[2] = (char) token_length;
                tp[3] = (char) (token - cbuf);

                /* Step to next token position and count the word */

                tp += 4;
                words++;
            } else {

                /* Moan if token buffer space exhausted */

                output_string ("Too many words typed, discarding: ");
                output_line (token);
            }
    } while (token_length);

    /* Store word count */

    tbuf[1] = (char) words;

}/* tokenise_line */

/*
 * next_token
 *
 * Find next token in a string. The token (word) is delimited by a statically
 * defined and a game specific set of word separators. The game specific set
 * of separators look like real word separators, but the parser wants to know
 * about them. An example would be: 'grue, take the axe. go north'. The
 * parser wants to know about the comma and the period so that it can correctly
 * parse the line. The 'interesting' word separators normally appear at the
 * start of the dictionary, and are also put in a separate list in the game
 * file.
 *
 */

#ifdef __STDC__
static const char *next_token (const char *s, const char **token, int *length, const char *punctuation)
#else
static const char *next_token (s, token, length, punctuation)
const char *s;
const char **token;
int *length;
const char *punctuation;
#endif
{
    int i;

    /* Set the token length to zero */

    *length = 0;

    /* Step through the string looking for separators */

    for (; *s; s++) {

        /* Look for game specific word separators first */

        for (i = 0; punctuation[i] && *s != punctuation[i]; i++)
            ;

        /* If a separator is found then return the information */

        if (punctuation[i]) {

            /* If length has been set then just return the word position */

            if (*length)
                return (s);
            else {

                /* End of word, so set length, token pointer and return string */

                (*length)++;
                *token = s;
                return (++s);
            }
        }

        /* Look for statically defined separators last */

        for (i = 0; separators[i] && *s != separators[i]; i++)
            ;

        /* If a separator is found then return the information */

        if (separators[i]) {

            /* If length has been set then just return the word position */

            if (*length)
                return (++s);
        } else {

            /* If first token character then remember its position */

            if (*length == 0)
                *token = s;
            (*length)++;
        }
    }

    return (s);

}/* next_token */

/*
 * find_word
 *
 * Search the dictionary for a word. Just encode the word and binary chop the
 * dictionary looking for it.
 *
 */

#ifdef __STDC__
static zword_t find_word (int len, const char *cp, long chop)
#else
static zword_t find_word (len, cp, chop)
int len;
const char *cp;
long chop;
#endif
{
    short int word[3];
    long word_index, offset, status;

    /* Don't look up the word if there are no dictionary entries */

    if (dictionary_size == 0)
        return (0);

    /* Encode target word */

    encode_text (len, cp, word);

    /* Do a binary chop search on the main dictionary, otherwise do
       a linear search */

    word_index = chop - 1;

    if (dictionary_size > 0) {

        /* Binary chop until the word is found */

        while (chop) {

            chop /= 2;

            /* Calculate dictionary offset */

            if (word_index > (dictionary_size - 1))
                word_index = dictionary_size - 1;

            offset = dictionary_offset + (word_index * entry_size);

            /* If word matches then return dictionary offset */

            if ((status = word[0] - (short) get_word (offset + 0)) == 0 &&
                (status = word[1] - (short) get_word (offset + 2)) == 0 &&
                (h_type < V4 ||
                (status = word[2] - (short) get_word (offset + 4)) == 0))
                return ((zword_t) offset);

            /* Set next position depending on direction of overshoot */

            if (status > 0) {
                word_index += chop;

                /* Deal with end of dictionary case */

                if (word_index >= (int) dictionary_size)
                    word_index = dictionary_size - 1;
            } else {
                word_index -= chop;

                /* Deal with start of dictionary case */

                if (word_index < 0)
                    word_index = 0;
            }
        }
    } else {

        for (word_index = 0; word_index < -dictionary_size; word_index++) {

            /* Calculate dictionary offset */

            offset = dictionary_offset + (word_index * entry_size);

            /* If word matches then return dictionary offset */

            if ((status = word[0] - (short) get_word (offset + 0)) == 0 &&
                (status = word[1] - (short) get_word (offset + 2)) == 0 &&
                (h_type < V4 ||
                (status = word[2] - (short) get_word (offset + 4)) == 0))
                return ((zword_t) offset);
        }
    }

    return (0);

}/* find_word */

/*
 * tokenise
 *
 *    argv[0] = character buffer address
 *    argv[1] = token buffer address
 *    argv[2] = alternate vocabulary table
 *    argv[3] = ignore unknown words flag
 *
 */

#ifdef __STDC__
void tokenise (int argc, zword_t *argv)
#else
void tokenise (argc, argv)
int argc;
zword_t *argv;
#endif
{

    /* Supply default parameters */

    if (argc < 4)
        argv[3] = 0;
    if (argc < 3)
        argv[2] = h_words_offset;

    /* Convert the line to tokens */

    tokenise_line (argv[0], argv[1], argv[2], argv[3]);

}/* tokenise */