tclbinary.c

tcl是工具命令语言

				 * Initialized to avoid compiler warning. */
    char cmd;			/* Current format character. */
    int count;			/* Count associated with current format
				 * character. */
    char *format;		/* Pointer to current position in format
				 * string. */
    Tcl_Obj *resultPtr;		/* Object holding result buffer. */
    unsigned char *buffer;	/* Start of result buffer. */
    unsigned char *cursor;	/* Current position within result buffer. */
    unsigned char *maxPos;	/* Greatest position within result buffer that
				 * cursor has visited.*/
    char *errorString, *errorValue, *str;
    int offset, size, length, index;
    static CONST char *options[] = { 
	"format",	"scan",		NULL 
    };
    enum options { 
	BINARY_FORMAT,	BINARY_SCAN
    };

    if (objc < 2) {
    	Tcl_WrongNumArgs(interp, 1, objv, "option ?arg arg ...?");
	return TCL_ERROR;
    }

    if (Tcl_GetIndexFromObj(interp, objv[1], options, "option", 0,
	    &index) != TCL_OK) {
    	return TCL_ERROR;
    }

    switch ((enum options) index) {
	case BINARY_FORMAT: {
	    if (objc < 3) {
		Tcl_WrongNumArgs(interp, 2, objv, "formatString ?arg arg ...?");
		return TCL_ERROR;
	    }

	    /*
	     * To avoid copying the data, we format the string in two passes.
	     * The first pass computes the size of the output buffer.  The
	     * second pass places the formatted data into the buffer.
	     */

	    format = Tcl_GetString(objv[2]);
	    arg = 3;
	    offset = 0;
	    length = 0;
	    while (*format != '\0') {
		str = format;
		if (!GetFormatSpec(&format, &cmd, &count)) {
		    break;
		}
		switch (cmd) {
		    case 'a':
		    case 'A':
		    case 'b':
		    case 'B':
		    case 'h':
		    case 'H': {
			/*
			 * For string-type specifiers, the count corresponds
			 * to the number of bytes in a single argument.
			 */

			if (arg >= objc) {
			    goto badIndex;
			}
			if (count == BINARY_ALL) {
			    Tcl_GetByteArrayFromObj(objv[arg], &count);
			} else if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			arg++;
			if (cmd == 'a' || cmd == 'A') {
			    offset += count;
			} else if (cmd == 'b' || cmd == 'B') {
			    offset += (count + 7) / 8;
			} else {
			    offset += (count + 1) / 2;
			}
			break;
		    }
		    case 'c': {
			size = 1;
			goto doNumbers;
		    }
		    case 's':
		    case 'S': {
			size = 2;
			goto doNumbers;
		    }
		    case 'i':
		    case 'I': {
			size = 4;
			goto doNumbers;
		    }
		    case 'w':
		    case 'W': {
			size = 8;
			goto doNumbers;
		    }
		    case 'f': {
			size = sizeof(float);
			goto doNumbers;
		    }
		    case 'd': {
			size = sizeof(double);
			
			doNumbers:
			if (arg >= objc) {
			    goto badIndex;
			}

			/*
			 * For number-type specifiers, the count corresponds
			 * to the number of elements in the list stored in
			 * a single argument.  If no count is specified, then
			 * the argument is taken as a single non-list value.
			 */

			if (count == BINARY_NOCOUNT) {
			    arg++;
			    count = 1;
			} else {
			    int listc;
			    Tcl_Obj **listv;
			    if (Tcl_ListObjGetElements(interp, objv[arg++],
				    &listc, &listv) != TCL_OK) {
				return TCL_ERROR;
			    }
			    if (count == BINARY_ALL) {
				count = listc;
			    } else if (count > listc) {
			        Tcl_AppendResult(interp, 
					"number of elements in list does not match count",
					(char *) NULL);
				return TCL_ERROR;
			    }
			}
			offset += count*size;
			break;
		    }
		    case 'x': {
			if (count == BINARY_ALL) {
			    Tcl_AppendResult(interp, 
				    "cannot use \"*\" in format string with \"x\"",
				    (char *) NULL);
			    return TCL_ERROR;
			} else if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			offset += count;
			break;
		    }
		    case 'X': {
			if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			if ((count > offset) || (count == BINARY_ALL)) {
			    count = offset;
			}
			if (offset > length) {
			    length = offset;
			}
			offset -= count;
			break;
		    }
		    case '@': {
			if (offset > length) {
			    length = offset;
			}
			if (count == BINARY_ALL) {
			    offset = length;
			} else if (count == BINARY_NOCOUNT) {
			    goto badCount;
			} else {
			    offset = count;
			}
			break;
		    }
		    default: {
			errorString = str;
			goto badfield;
		    }
		}
	    }
	    if (offset > length) {
		length = offset;
	    }
	    if (length == 0) {
		return TCL_OK;
	    }

	    /*
	     * Prepare the result object by preallocating the caclulated
	     * number of bytes and filling with nulls.
	     */

	    resultPtr = Tcl_GetObjResult(interp);
	    buffer = Tcl_SetByteArrayLength(resultPtr, length);
	    memset((VOID *) buffer, 0, (size_t) length);

	    /*
	     * Pack the data into the result object.  Note that we can skip
	     * the error checking during this pass, since we have already
	     * parsed the string once.
	     */

	    arg = 3;
	    format = Tcl_GetString(objv[2]);
	    cursor = buffer;
	    maxPos = cursor;
	    while (*format != 0) {
		if (!GetFormatSpec(&format, &cmd, &count)) {
		    break;
		}
		if ((count == 0) && (cmd != '@')) {
		    arg++;
		    continue;
		}
		switch (cmd) {
		    case 'a':
		    case 'A': {
			char pad = (char) (cmd == 'a' ? '\0' : ' ');
			unsigned char *bytes;

			bytes = Tcl_GetByteArrayFromObj(objv[arg++], &length);

			if (count == BINARY_ALL) {
			    count = length;
			} else if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			if (length >= count) {
			    memcpy((VOID *) cursor, (VOID *) bytes,
				    (size_t) count);
			} else {
			    memcpy((VOID *) cursor, (VOID *) bytes,
				    (size_t) length);
			    memset((VOID *) (cursor + length), pad,
			            (size_t) (count - length));
			}
			cursor += count;
			break;
		    }
		    case 'b':
		    case 'B': {
			unsigned char *last;
			
			str = Tcl_GetStringFromObj(objv[arg++], &length);
			if (count == BINARY_ALL) {
			    count = length;
			} else if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			last = cursor + ((count + 7) / 8);
			if (count > length) {
			    count = length;
			}
			value = 0;
			errorString = "binary";
			if (cmd == 'B') {
			    for (offset = 0; offset < count; offset++) {
				value <<= 1;
				if (str[offset] == '1') {
				    value |= 1;
				} else if (str[offset] != '0') {
				    errorValue = str;
				    goto badValue;
				}
				if (((offset + 1) % 8) == 0) {
				    *cursor++ = (unsigned char) value;
				    value = 0;
				}
			    }
			} else {
			    for (offset = 0; offset < count; offset++) {
				value >>= 1;
				if (str[offset] == '1') {
				    value |= 128;
				} else if (str[offset] != '0') {
				    errorValue = str;
				    goto badValue;
				}
				if (!((offset + 1) % 8)) {
				    *cursor++ = (unsigned char) value;
				    value = 0;
				}
			    }
			}
			if ((offset % 8) != 0) {
			    if (cmd == 'B') {
				value <<= 8 - (offset % 8);
			    } else {
				value >>= 8 - (offset % 8);
			    }
			    *cursor++ = (unsigned char) value;
			}
			while (cursor < last) {
			    *cursor++ = '\0';
			}
			break;
		    }
		    case 'h':
		    case 'H': {
			unsigned char *last;
			int c;
			
			str = Tcl_GetStringFromObj(objv[arg++], &length);
			if (count == BINARY_ALL) {
			    count = length;
			} else if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			last = cursor + ((count + 1) / 2);
			if (count > length) {
			    count = length;
			}
			value = 0;
			errorString = "hexadecimal";
			if (cmd == 'H') {
			    for (offset = 0; offset < count; offset++) {
				value <<= 4;
				if (!isxdigit(UCHAR(str[offset]))) { /* INTL: digit */
				    errorValue = str;
				    goto badValue;
				}
				c = str[offset] - '0';
				if (c > 9) {
				    c += ('0' - 'A') + 10;
				}
				if (c > 16) {
				    c += ('A' - 'a');
				}
				value |= (c & 0xf);
				if (offset % 2) {
				    *cursor++ = (char) value;
				    value = 0;
				}
			    }
			} else {
			    for (offset = 0; offset < count; offset++) {
				value >>= 4;

				if (!isxdigit(UCHAR(str[offset]))) { /* INTL: digit */
				    errorValue = str;
				    goto badValue;
				}
				c = str[offset] - '0';
				if (c > 9) {
				    c += ('0' - 'A') + 10;
				}
				if (c > 16) {
				    c += ('A' - 'a');
				}
				value |= ((c << 4) & 0xf0);
				if (offset % 2) {
				    *cursor++ = (unsigned char)(value & 0xff);
				    value = 0;
				}
			    }
			}
			if (offset % 2) {
			    if (cmd == 'H') {
				value <<= 4;
			    } else {
				value >>= 4;
			    }
			    *cursor++ = (unsigned char) value;
			}

			while (cursor < last) {
			    *cursor++ = '\0';
			}
			break;
		    }
		    case 'c':
		    case 's':
		    case 'S':
		    case 'i':
		    case 'I':
		    case 'w':
		    case 'W':
		    case 'd':
		    case 'f': {
			int listc, i;
			Tcl_Obj **listv;

			if (count == BINARY_NOCOUNT) {
			    /*
			     * Note that we are casting away the const-ness of
			     * objv, but this is safe since we aren't going to
			     * modify the array.
			     */

			    listv = (Tcl_Obj**)(objv + arg);
			    listc = 1;
			    count = 1;
			} else {
			    Tcl_ListObjGetElements(interp, objv[arg],
				    &listc, &listv);
			    if (count == BINARY_ALL) {
				count = listc;
			    }
			}
			arg++;
			for (i = 0; i < count; i++) {
			    if (FormatNumber(interp, cmd, listv[i], &cursor)
				    != TCL_OK) {
				return TCL_ERROR;
			    }
			}
			break;
		    }
		    case 'x': {
			if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			memset(cursor, 0, (size_t) count);
			cursor += count;
			break;
		    }
		    case 'X': {
			if (cursor > maxPos) {
			    maxPos = cursor;
			}
			if (count == BINARY_NOCOUNT) {
			    count = 1;
			}
			if ((count == BINARY_ALL)
				|| (count > (cursor - buffer))) {
			    cursor = buffer;
			} else {
			    cursor -= count;
			}
			break;
		    }
		    case '@': {
			if (cursor > maxPos) {
			    maxPos = cursor;
			}
			if (count == BINARY_ALL) {
			    cursor = maxPos;
			} else {
			    cursor = buffer + count;
			}
			break;
		    }
		}
	    }
	    break;
	}
	case BINARY_SCAN: {
	    int i;
	    Tcl_Obj *valuePtr, *elementPtr;
	    Tcl_HashTable numberCacheHash;
	    Tcl_HashTable *numberCachePtr;

	    if (objc < 4) {
		Tcl_WrongNumArgs(interp, 2, objv,
			"value formatString ?varName varName ...?");
		return TCL_ERROR;
	    }
	    numberCachePtr = &numberCacheHash;
	    Tcl_InitHashTable(numberCachePtr, TCL_ONE_WORD_KEYS);
	    buffer = Tcl_GetByteArrayFromObj(objv[2], &length);
	    format = Tcl_GetString(objv[3]);
	    cursor = buffer;
	    arg = 4;
	    offset = 0;
	    while (*format != '\0') {
		str = format;
		if (!GetFormatSpec(&format, &cmd, &count)) {
		    goto done;
		}
		switch (cmd) {
		    case 'a':
		    case 'A': {
			unsigned char *src;

			if (arg >= objc) {
			    if (numberCachePtr != NULL) {
				Tcl_DeleteHashTable(numberCachePtr);
			    }
			    goto badIndex;
			}
			if (count == BINARY_ALL) {
			    count = length - offset;
			} else {
			    if (count == BINARY_NOCOUNT) {
				count = 1;
			    }
			    if (count > (length - offset)) {
				goto done;
			    }
			}

			src = buffer + offset;
			size = count;

			/*
			 * Trim trailing nulls and spaces, if necessary.
			 */

			if (cmd == 'A') {
			    while (size > 0) {
				if (src[size-1] != '\0' && src[size-1] != ' ') {
				    break;
				}
				size--;
			    }
			}
			valuePtr = Tcl_NewByteArrayObj(src, size);
			resultPtr = Tcl_ObjSetVar2(interp, objv[arg],
				NULL, valuePtr, TCL_LEAVE_ERR_MSG);
			arg++;
			if (resultPtr == NULL) {
			    if (numberCachePtr != NULL) {
				Tcl_DeleteHashTable(numberCachePtr);
			    }
			    Tcl_DecrRefCount(valuePtr);	/* unneeded */
			    return TCL_ERROR;
			}
			offset += count;
			break;
		    }
		    case 'b':
		    case 'B': {
			unsigned char *src;
			char *dest;

			if (arg >= objc) {
			    if (numberCachePtr != NULL) {
				Tcl_DeleteHashTable(numberCachePtr);
			    }
			    goto badIndex;
			}
			if (count == BINARY_ALL) {
			    count = (length - offset) * 8;
			} else {
			    if (count == BINARY_NOCOUNT) {
				count = 1;
			    }
			    if (count > (length - offset) * 8) {
				goto done;
			    }
			}
			src = buffer + offset;
			valuePtr = Tcl_NewObj();
			Tcl_SetObjLength(valuePtr, count);
			dest = Tcl_GetString(valuePtr);

			if (cmd == 'b') {
			    for (i = 0; i < count; i++) {
				if (i % 8) {
				    value >>= 1;
				} else {
				    value = *src++;
				}
				*dest++ = (char) ((value & 1) ? '1' : '0');
			    }
			} else {
			    for (i = 0; i < count; i++) {
				if (i % 8) {
				    value <<= 1;
				} else {
				    value = *src++;
				}
				*dest++ = (char) ((value & 0x80) ? '1' : '0');
			    }
			}