src/basic.c


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#include <unistd.h>
#include <sys/stat.h>

#include <zx/charset.h>
#include <zx/basic.h>

char *zx81_basic_tokens_low[3] = {
    "RND", "INKEY$", "PI",
};

char *zx81_basic_tokens[64] = {
    "\"\"", "AT",     "TAB",   NULL,   "CODE",   "VAL",   "LEN",    "SIN",
    "COS",  "TAN",    "ASN",   "ACS",  "ATN",    "LN",    "EXP",    "INT",
    "SQR",  "SGN",    "ABS",   "PEEK", "USR",    "STR$",  "CHR$",   "NOT",
    "**",   "OR",     "AND",   "<=",   ">=",     "<>",    "THEN",   "TO",
    "STEP", "LPRINT", "LLIST", "STOP", "SLOW",   "FAST",  "NEW",    "SCROLL",
    "CONT", "DIM",    "REM",   "FOR",  "GOTO",   "GOSUB", "INPUT",  "LOAD",
    "LIST", "LET",    "PAUSE", "NEXT", "POKE",   "PRINT", "PLOT",   "RUN",
    "SAVE", "RAND",   "IF",    "CLS",  "UNPLOT", "CLEAR", "RETURN", "COPY",
};

static inline enum zx_basic_token_type zx_basic_token_type_get(uint8_t b) {
    if (ZX81_CHAR_LOW(b)) {
        uint32_t codepoint = zx81_charset[b];

        if ((codepoint >= 'A' && codepoint <= 'Z')
         || (codepoint >= '0' && codepoint <= '9')) {
            return ZX_BASIC_TOKEN_ALNUM;
        } else if (codepoint == '"') {
            return ZX_BASIC_TOKEN_QUOTE;
        } else {
            return ZX_BASIC_TOKEN_SYMBOL;
        }
    } else if (ZX81_CHAR_INVERSE(b)) {
        return zx_basic_token_type_get(b - ZX81_CHAR_INVERSE_START);
    } else if (ZX81_CHAR_TOKEN_LOW(b)) {
        return ZX_BASIC_TOKEN_WORD;
    } else if (ZX81_CHAR_TOKEN_HIGH(b)) {
        char *token = zx81_basic_tokens[b-ZX81_CHAR_TOKEN_HIGH_START];

        if (token[0] >= 'A' && token[0] <= 'Z') {
            return ZX_BASIC_TOKEN_WORD;
        } else {
            return ZX_BASIC_TOKEN_SYMBOL;
        }
    }

    return ZX_BASIC_TOKEN_UNKNOWN;
}

static inline int basic_print(uint8_t c, int tty, FILE *stream) {
    if (ZX81_CHAR_LOW(c)) {
        return zx81_fputc(c, 0, stream);
    } else if (ZX81_CHAR_TOKEN_LOW(c)) {
        return fputs(zx81_basic_tokens_low[c - ZX81_CHAR_TOKEN_LOW_START], stream);
    } else if (ZX81_CHAR_NEWLINE(c)) {
        return putchar('\n');
    } else if (ZX81_CHAR_INVERSE(c)) {
        return zx81_fputc(c - ZX81_CHAR_INVERSE_START, tty, stream);
    } else if (ZX81_CHAR_TOKEN_HIGH(c)) {
        return fputs(zx81_basic_tokens[c - ZX81_CHAR_TOKEN_HIGH_START], stream);
    }

    return 0;
}
ssize_t zx81_basic_dump(int fd, FILE *stream) {
    void *buf;
    ssize_t total = 0;
    int tty = isatty(fileno(stream));
    struct stat st;

    if (fstat(fd, &st) < 0) {
        goto error_fstat;
    }

    if ((buf = malloc(st.st_blksize)) == NULL) {
        goto error_malloc;
    }

    if (lseek(fd, ZX_BASIC_STATE_SIZE, SEEK_CUR) < 0) {
        goto error_io;
    }

    while (1) {
        ssize_t readlen, len, i;
        zx_basic_line line;
        uint8_t last = 0xc0;

        if ((readlen = read(fd, &line, sizeof(line))) < 0) {
            goto error_io;
        } else if (readlen == 0) {
            break;
        }

        len = le16toh(line.len);

        if (be16toh(line.num) == len && len == ZX_BASIC_LINE_LAST) {
            break;
        }

        if (printf("%d ", (int)be16toh(line.num)) < 0) {
            goto error_io;
        }

        if (read(fd, buf, len) < 0) {
            goto error_io;
        }

        for (i=0; i<len; i++) {
            uint8_t c = ((uint8_t *)buf)[i];

            enum zx_basic_token_type type      = zx_basic_token_type_get(c),
                                     type_last = zx_basic_token_type_get(last);

            int space = 0;

            if (type == ZX_BASIC_TOKEN_ALNUM) {
                if (type_last == ZX_BASIC_TOKEN_WORD) {
                    space = 1;
                }
            } else if (type == ZX_BASIC_TOKEN_QUOTE) {
                if (type_last == ZX_BASIC_TOKEN_WORD) {
                    space = 1;
                }
            } else if (type == ZX_BASIC_TOKEN_SYMBOL) {
                space = 0;
            } else if (type == ZX_BASIC_TOKEN_WORD) {
                if (type_last != ZX_BASIC_TOKEN_SYMBOL) {
                    space = 1;
                }
            } else if (ZX81_CHAR_TOKEN_INTEGRAL(c) || ZX81_CHAR_TOKEN_FLOAT(c)) {
                i += 5;
            }

            if (space && fputc(' ', stream) < 0) {
                goto error_io;
            }

            if (basic_print(c, tty, stream) < 0) {
                goto error_io;
            }

            last = c;
        }

        if (!ZX81_CHAR_NEWLINE(((uint8_t *)buf)[i-1])) {
            if (fputc('\n', stream) < 0) {
                goto error_io;
            }
        }
    }

    free(buf);

    return total;

error_io:
    free(buf);

error_malloc:
error_fstat:
    return -1;
}