grammar.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

        mem_free ((void **) re);
    }
}

static byte regbyte_ctx_extract (regbyte_ctx **re, map_byte *reg)
{
    /* first lookup in the register stack */
    while (*re != NULL)
    {
        if ((**re).m_regbyte == reg)
            return (**re).m_current_value;

        re = &(**re).m_prev;
    }

    /* if not found - return the default value */
    return reg->data;
}

/*
    emit type typedef
*/
typedef enum emit_type_
{
    et_byte,            /* explicit number */
    et_stream,          /* eaten character */
    et_position         /* current position */
} emit_type;

/*
    emit destination typedef
*/
typedef enum emit_dest_
{
    ed_output,          /* write to the output buffer */
    ed_regbyte          /* write a particular regbyte */
} emit_dest;

/*
    emit typedef
*/
typedef struct emit_
{
    emit_dest m_emit_dest;
    emit_type m_emit_type;      /* ed_output */
    byte m_byte;                /* et_byte */
    map_byte *m_regbyte;        /* ed_regbyte */
    byte *m_regname;            /* ed_regbyte - temporary */
    struct emit_ *m_next;
} emit;

static void emit_create (emit **em)
{
    *em = (emit *) mem_alloc (sizeof (emit));
    if (*em)
    {
        (**em).m_emit_dest = ed_output;
        (**em).m_emit_type = et_byte;
        (**em).m_byte = '\0';
        (**em).m_regbyte = NULL;
        (**em).m_regname = NULL;
        (**em).m_next = NULL;
    }
}

static void emit_destroy (emit **em)
{
    if (*em)
    {
        emit_destroy (&(**em).m_next);
        mem_free ((void **) &(**em).m_regname);
        mem_free ((void **) em);
    }
}

static unsigned int emit_size (emit *_E)
{
    unsigned int n = 0;

    while (_E != NULL)
    {
        if (_E->m_emit_dest == ed_output)
        {
            if (_E->m_emit_type == et_position)
                n += 4;     /* position is a 32-bit unsigned integer */
            else
                n++;
        }
        _E = _E->m_next;
    }

    return n;
}

static int emit_push (emit *_E, byte *_P, byte c, unsigned int _Pos, regbyte_ctx **_Ctx)
{
    while (_E != NULL)
    {
        if (_E->m_emit_dest == ed_output)
        {
            if (_E->m_emit_type == et_byte)
                *_P++ = _E->m_byte;
            else if (_E->m_emit_type == et_stream)
                *_P++ = c;
            else /* _Em->type == et_position */
            {
                *_P++ = (byte) (_Pos);
                *_P++ = (byte) (_Pos >> 8);
                *_P++ = (byte) (_Pos >> 16);
                *_P++ = (byte) (_Pos >> 24);
            }
        }
        else
        {
            regbyte_ctx *new_rbc;
            regbyte_ctx_create (&new_rbc);
            if (new_rbc == NULL)
                return 1;

            new_rbc->m_prev = *_Ctx;
            new_rbc->m_regbyte = _E->m_regbyte;
            *_Ctx = new_rbc;

            if (_E->m_emit_type == et_byte)
                new_rbc->m_current_value = _E->m_byte;
            else if (_E->m_emit_type == et_stream)
                new_rbc->m_current_value = c;
        }

        _E = _E->m_next;
    }

    return 0;
}

/*
    error typedef
*/
typedef struct error_
{
    byte *m_text;
    byte *m_token_name;
    struct rule_ *m_token;
} error;

static void error_create (error **er)
{
    *er = (error *) mem_alloc (sizeof (error));
    if (*er)
    {
        (**er).m_text = NULL;
        (**er).m_token_name = NULL;
        (**er).m_token = NULL;
    }
}

static void error_destroy (error **er)
{
    if (*er)
    {
        mem_free ((void **) &(**er).m_text);
        mem_free ((void **) &(**er).m_token_name);
        mem_free ((void **) er);
    }
}

struct dict_;
static byte *error_get_token (error *, struct dict_ *, const byte *, unsigned int);

/*
    condition operand type typedef
*/
typedef enum cond_oper_type_
{
    cot_byte,               /* constant 8-bit unsigned integer */
    cot_regbyte             /* pointer to byte register containing the current value */
} cond_oper_type;

/*
    condition operand typedef
*/
typedef struct cond_oper_
{
    cond_oper_type m_type;
    byte m_byte;            /* cot_byte */
    map_byte *m_regbyte;    /* cot_regbyte */
    byte *m_regname;        /* cot_regbyte - temporary */
} cond_oper;

/*
    condition type typedef
*/
typedef enum cond_type_
{
    ct_equal,
    ct_not_equal
} cond_type;

/*
    condition typedef
*/
typedef struct cond_
{
    cond_type m_type;
    cond_oper m_operands[2];
} cond;

static void cond_create (cond **co)
{
    *co = (cond *) mem_alloc (sizeof (cond));
    if (*co)
    {
        (**co).m_operands[0].m_regname = NULL;
        (**co).m_operands[1].m_regname = NULL;
    }
}

static void cond_destroy (cond **co)
{
    if (*co)
    {
        mem_free ((void **) &(**co).m_operands[0].m_regname);
        mem_free ((void **) &(**co).m_operands[1].m_regname);
        mem_free ((void **) co);
    }
}

/*
    specifier type typedef
*/
typedef enum spec_type_
{
    st_false,
    st_true,
    st_byte,
    st_byte_range,
    st_string,
    st_identifier,
    st_identifier_loop,
    st_debug
} spec_type;

/*
    specifier typedef
*/
typedef struct spec_
{
    spec_type m_spec_type;
    byte m_byte[2];                 /* st_byte, st_byte_range */
    byte *m_string;                 /* st_string */
    struct rule_ *m_rule;           /* st_identifier, st_identifier_loop */
    emit *m_emits;
    error *m_errtext;
    cond *m_cond;
    struct spec_ *next;
} spec;

static void spec_create (spec **sp)
{
    *sp = (spec *) mem_alloc (sizeof (spec));
    if (*sp)
    {
        (**sp).m_spec_type = st_false;
        (**sp).m_byte[0] = '\0';
        (**sp).m_byte[1] = '\0';
        (**sp).m_string = NULL;
        (**sp).m_rule = NULL;
        (**sp).m_emits = NULL;
        (**sp).m_errtext = NULL;
        (**sp).m_cond = NULL;
        (**sp).next = NULL;
    }
}

static void spec_destroy (spec **sp)
{
    if (*sp)
    {
        spec_destroy (&(**sp).next);
        emit_destroy (&(**sp).m_emits);
        error_destroy (&(**sp).m_errtext);
        mem_free ((void **) &(**sp).m_string);
        cond_destroy (&(**sp).m_cond);
        mem_free ((void **) sp);
    }
}

GRAMMAR_IMPLEMENT_LIST_APPEND(spec)

/*
    operator typedef
*/
typedef enum oper_
{
    op_none,
    op_and,
    op_or
} oper;

/*
    rule typedef
*/
typedef struct rule_
{
    oper m_oper;
    spec *m_specs;
    struct rule_ *next;
    int m_referenced;
} rule;

static void rule_create (rule **ru)
{
    *ru = (rule *) mem_alloc (sizeof (rule));
    if (*ru)
    {
        (**ru).m_oper = op_none;
        (**ru).m_specs = NULL;
        (**ru).next = NULL;
        (**ru).m_referenced = 0;
    }
}

static void rule_destroy (rule **ru)
{
    if (*ru)
    {
        rule_destroy (&(**ru).next);
        spec_destroy (&(**ru).m_specs);
        mem_free ((void **) ru);
    }
}

GRAMMAR_IMPLEMENT_LIST_APPEND(rule)

/*
    returns unique grammar id
*/
static grammar next_valid_grammar_id (void)
{
    static grammar id = 0;

    return ++id;
}

/*
    dictionary typedef
*/
typedef struct dict_
{
    rule *m_rulez;
    rule *m_syntax;
    rule *m_string;
    map_byte *m_regbytes;
    grammar m_id;
    struct dict_ *next;
} dict;

static void dict_create (dict **di)
{
    *di = (dict *) mem_alloc (sizeof (dict));
    if (*di)
    {
        (**di).m_rulez = NULL;
        (**di).m_syntax = NULL;
        (**di).m_string = NULL;
        (**di).m_regbytes = NULL;
        (**di).m_id = next_valid_grammar_id ();
        (**di).next = NULL;
    }
}

static void dict_destroy (dict **di)
{
    if (*di)
    {
        rule_destroy (&(**di).m_rulez);
        map_byte_destroy (&(**di).m_regbytes);
        mem_free ((void **) di);
    }
}

GRAMMAR_IMPLEMENT_LIST_APPEND(dict)

static void dict_find (dict **di, grammar key, dict **data)
{
    while (*di)
    {
        if ((**di).m_id == key)
        {
            *data = *di;
            return;
        }

        di = &(**di).next;
    }

    *data = NULL;
}

static dict *g_dicts = NULL;

/*
    byte array typedef
*/
typedef struct barray_
{
    byte *data;
    unsigned int len;
} barray;

static void barray_create (barray **ba)
{
    *ba = (barray *) mem_alloc (sizeof (barray));
    if (*ba)
    {
        (**ba).data = NULL;
        (**ba).len = 0;
    }
}

static void barray_destroy (barray **ba)
{
    if (*ba)
    {
        mem_free ((void **) &(**ba).data);
        mem_free ((void **) ba);
    }
}

/*
    reallocates byte array to requested size,
    returns 0 on success,
    returns 1 otherwise
*/
static int barray_resize (barray **ba, unsigned int nlen)
{
    byte *new_pointer;

    if (nlen == 0)
    {
        mem_free ((void **) &(**ba).data);
        (**ba).data = NULL;
        (**ba).len = 0;

        return 0;
    }
    else
    {
        new_pointer = (byte *) mem_realloc ((**ba).data, (**ba).len * sizeof (byte),
            nlen * sizeof (byte));
        if (new_pointer)
        {
            (**ba).data = new_pointer;
            (**ba).len = nlen;

            return 0;
        }
    }

    return 1;
}

/*
    adds byte array pointed by *nb to the end of array pointed by *ba,
    returns 0 on success,
    returns 1 otherwise
*/
static int barray_append (barray **ba, barray **nb)
{
    const unsigned int len = (**ba).len;

    if (barray_resize (ba, (**ba).len + (**nb).len))
        return 1;

    mem_copy ((**ba).data + len, (**nb).data, (**nb).len);

    return 0;
}

/*
    adds emit chain pointed by em to the end of array pointed by *ba,
    returns 0 on success,
    returns 1 otherwise
*/
static int barray_push (barray **ba, emit *em, byte c, unsigned int pos, regbyte_ctx **rbc)
{
    unsigned int count = emit_size (em);

    if (barray_resize (ba, (**ba).len + count))
        return 1;