"

 COPYRIGHT (c) 1988 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libbasic' }"

PositionableStream subclass:#ReadStream

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'Streams'

!

!ReadStream class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1988 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    ReadStream defines protocol for reading streamwise over collections. 

    [author:]

	Claus Gittinger

"

! !

!ReadStream methodsFor:'converting'!

readStream

    "return a readStream from the receiver. Since this is already

     a readStream, return self."

    ^ self

! !

!ReadStream methodsFor:'emphasis'!

emphasis

    "return the emphasis of the current (i.e. next returned by #next)

     element. Streams on a string will return nil for all elements.

     Streams on collections which nothing at all about emphasises, 

     will report an error."

    ^ collection emphasisAt:(position - ZeroPosition + 1).

    "

     |t s|

     t := 'hello world' asText

                emphasizeFrom:1 to:5 with:#bold;

                emphasizeFrom:7 to:11 with:#italic.

     s := t readStream.

     [s atEnd] whileFalse:[

        Transcript show:(s emphasis); show:' '.

        Transcript show:''''; show:(s next); showCR:''''.

     ].

    "

    "Modified: 15.5.1996 / 17:30:33 / cg"

! !

!ReadStream methodsFor:'queries'!

copyFrom:beginning to:end

    ^ collection copyFrom:beginning to:end

!

isReadable

    "return true, if reading is supported by the recevier.

     Here, true is always returned."

    ^ true

    "Modified: 4.10.1997 / 17:59:21 / cg"

!

isWritable

    "return true, if writing is supported by the recevier.

     This has to be redefined in concrete subclasses."

    ^ false

!

size

    "return the number of elements in the streamed collection."

    ^ collection size

    "Created: 13.9.1996 / 18:14:35 / cg"

    "Modified: 4.10.1997 / 17:59:45 / cg"

! !

!ReadStream methodsFor:'reading'!

next

    "return the next element; advance read pointer.

     return nil, if there is no next element.

     - tuned for a bit more speed on String/ByteArray/Array-Streams"

    |ret|

%{  /* NOCONTEXT */

    REGISTER int pos;

    unsigned ch;

    OBJ coll, p, l;

    coll = __INST(collection);

    p = __INST(position);

    l = __INST(readLimit);

    if (__isNonNilObject(coll) && __bothSmallInteger(p, l)) {

    }

%}.

    ((position + 1 - ZeroPosition) > readLimit) ifTrue:[^ self pastEnd].

    ret := collection at:(position + 1 - ZeroPosition).

    position := position + 1.

    ^ ret

!

nextAlphaNumericWord

    "read the next word (i.e. up to non letter-or-digit).

     return a string containing those characters.

     Skips any non-alphanumeric chars first.

     - tuned for speed on String-Streams for faster scanning"

%{

    /* speedup, if collection is a string */

    int pos, limit, sz;

    int len;

    char buffer[256];

    REGISTER unsigned char *cp;

    REGISTER unsigned ch;

    OBJ coll, p, l;

    coll = __INST(collection);

    p = __INST(position);

    l = __INST(readLimit);

    if (__isString(coll) && __bothSmallInteger(p, l)) {

	pos = __intVal(p);

	/* make 1-based */

	pos = pos + 1 - __intVal( @global(PositionableStream:ZeroPosition));

	limit = __intVal(l);

	sz = __qSize(coll) - OHDR_SIZE;

	if (sz < limit)

	    limit = sz; 

	cp = __stringVal(coll) + pos - 1;

	for (;;) {

	    if (pos > limit) break;

	    ch = *cp;

	    if (((ch >= 'a') && (ch <= 'z')) ||

		((ch >= 'A') && (ch <= 'Z')) ||

		((ch >= '0') && (ch <= '9')))

		break;

	    cp++;

	    pos++;

	}

	len = 0;

	for (;;) {

	    if (pos > limit) break;

	    ch = *cp & 0xFF;

	    if (! (((ch >= 'a') && (ch <= 'z')) ||

		   ((ch >= 'A') && (ch <= 'Z')) ||

		   ((ch >= '0') && (ch <= '9'))))

		break;

	    buffer[len++] = ch;

	    if (len >= (sizeof(buffer)-1)) {

		/* emergency */

		break;

	    }

	    pos++;

	    cp++;

	}

	/* make ZeroPosition-based */

	pos = pos - 1 + __intVal( @global(PositionableStream:ZeroPosition));

	__INST(position) = __MKSMALLINT(pos);

	buffer[len] = '\0';

	RETURN ( (len != 0) ? __MKSTRING_L(buffer, len) : nil );

    }

%}

.

    ^ super nextAlphaNumericWord

!

nextByte

    "return the next element; advance read pointer.

     return nil, if there is no next element.

     - tuned for a bit more speed on String/ByteArray/Array-Streams"

    |ret|

%{  /* NOCONTEXT */

    REGISTER int pos;

    unsigned ch;

    OBJ coll, p, l;

    coll = __INST(collection);

    p = __INST(position);

    l = __INST(readLimit);

    if (__isNonNilObject(coll) && __bothSmallInteger(p, l)) {

    }

%}.

    ((position + 1 - ZeroPosition) > readLimit) ifTrue:[^ self pastEnd].

    ret := collection at:(position + 1 -ZeroPosition).

    position := position + 1.

!

nextDecimalInteger

    "read the next integer in radix 10. dont skip whitespace.

     - tuned for speed on String-Streams for faster scanning"

    |value nextOne|

%{

    int pos, limit, sz;

    REGISTER unsigned char *cp;

    REGISTER unsigned ch;

    int val = 0;

    OBJ coll, p, l;

    coll = __INST(collection);

    p = __INST(position);

    l = __INST(readLimit);

    if (__isString(coll) && __bothSmallInteger(p, l)) {

	pos = __intVal(p);

	/* make 1-based */

	pos = pos + 1 - __intVal( @global(PositionableStream:ZeroPosition));

	limit = __intVal(l);

	sz = __qSize(coll) - OHDR_SIZE;

	if (sz < limit)

	    limit = sz; 

	cp = __stringVal(coll) + pos - 1;

	for (;;) {

	    if (pos > limit) break;

	    ch = *cp;

	    if ((ch < '0') || (ch > '9')) break;

	    val = val * 10 + (ch - '0');

	    pos++;

	    if (val > (_MAX_INT / 10)) goto oops;

	    cp++;

	}

	/* make ZeroPosition-based */

	pos = pos - 1 + __intVal( @global(PositionableStream:ZeroPosition));

	__INST(position) = __MKSMALLINT(pos);

	RETURN (__MKSMALLINT(val));

    }

oops:

    value = __MKSMALLINT(val);

%}

.

    "fall-back for non-string streams - we have to continue where

     above primitive left off, in case of a large integer ...

     (instead of doing a super nextDecimalInteger)"

    nextOne := self peek.

    [nextOne notNil and:[nextOne isDigitRadix:10]] whileTrue:[

	value = (value * 10) + nextOne digitValue.

	nextOne := self nextPeek

    ].

    ^ value

!

nextPeek

    "advance read pointer return the peek element.

     this is equivalent to (self next; peek).

     - tuned for speed on String-Streams for faster scanning"

%{  /* NOCONTEXT */

    OBJ coll, l, p;

    coll = __INST(collection);

    p = __INST(position);

    l = __INST(readLimit);

    if (__isString(coll) && __bothSmallInteger(p, l)) {

	REGISTER int pos;

	unsigned ch;

	pos = __intVal(p);

	/* make 1-based */

	pos = pos + 1 - __intVal( @global(PositionableStream:ZeroPosition));

	if ((pos > 0) && (pos < __intVal(l)) && (pos < __stringSize(coll))) {

	    pos = pos + 1;

	    ch = __stringVal(coll)[pos-1];

	    /* make ZeroPosition-based */

	    pos = pos - 1 + __intVal( @global(PositionableStream:ZeroPosition));

	    __INST(position) = __MKSMALLINT(pos);

	    RETURN ( __MKCHARACTER(ch) );

	}

    }

%}.

    ((position + 1 - ZeroPosition) > readLimit) ifTrue:[^ self pastEnd].

    position := position + 1.

    ((position + 1 - ZeroPosition) > readLimit) ifTrue:[^ self pastEnd].

    ^ collection at:(position + 1 - ZeroPosition)

!

nextSymbol

    "read the next selector-symbol (i.e. up to non letter-or-digit).

     return a string containing those characters.

     - tuned for speed on String-Streams for faster scanning"

%{

    int pos, limit, sz;

    int len;

    char buffer[256];

    REGISTER unsigned char *cp;

    REGISTER unsigned ch;

    OBJ coll, p, l;

    coll = __INST(collection);

    p = __INST(position);

    l = __INST(readLimit);

    if (__isString(coll) && __bothSmallInteger(p, l)) {

	pos = __intVal(p);

	/* make 1-based */

	pos = pos + 1 - __intVal( @global(PositionableStream:ZeroPosition));

	limit = __intVal(l);

	sz = __qSize(coll) - OHDR_SIZE;

	if (sz < limit)

	    limit = sz; 

	cp = __stringVal(coll) + pos - 1;

	len = 0;

	for (;;) {

	    if (pos > limit) break;

	    ch = *cp;

	    if (! (((ch >= 'a') && (ch <= 'z')) ||

		   ((ch >= 'A') && (ch <= 'Z')) ||

		   ((ch >= '0') && (ch <= '9')) ||

		   (ch == ':')))

		break;

	    buffer[len++] = ch;

	    if (len >= (sizeof(buffer)-1)) {

		/* emergency */

		break;

	    }

	    pos++;

	    cp++;

	}

	/* make ZeroPosition-based */

	pos = pos - 1 + __intVal( @global(PositionableStream:ZeroPosition));

	__INST(position) = __MKSMALLINT(pos);

	buffer[len] = '\0';

	RETURN ( (len != 0) ? __MKSTRING_L(buffer, len) : nil );

    }

%}

.

    ^ super nextSymbol

!

peek

    "return the next element; do NOT advance read pointer.

     return nil, if there is no next element.

     - tuned for a bit more speed on String/ByteArray/Array-Streams"

%{  /* NOCONTEXT */

    REGISTER int pos;

    unsigned ch;

    OBJ coll;

    OBJ cls, p, l;

    coll = __INST(collection);

    p = __INST(position);

    l = __INST(readLimit);

    if (__isNonNilObject(coll) && __bothSmallInteger(p, l)) {

	pos = __intVal(p);

	/* make 1-based */

	pos = pos + 1 - __intVal( @global(PositionableStream:ZeroPosition));

	if (pos <= __intVal(l) && pos > 0) {

	    cls = __qClass(coll);

	    if (cls == @global(String)) {

		if (pos <= __stringSize(coll)) {

		    ch = __stringVal(coll)[pos-1];

		    RETURN ( __MKCHARACTER(ch) );

		}

	    } else if (cls == @global(ByteArray)) {

		if (pos <= __byteArraySize(coll)) {

		    ch = __ByteArrayInstPtr(coll)->ba_element[pos-1];

		    RETURN ( __MKSMALLINT(ch) );

		}

	    } else if (cls == @global(Array)) {

		if (pos <= __arraySize(coll)) {

		    RETURN ( __ArrayInstPtr(coll)->a_element[pos-1]);

		}

	    }

	}

    }