tkget.c

linux系统下的音频通信

/* 
 * tkGet.c --
 *
 *	This file contains a number of "Tk_GetXXX" procedures, which
 *	parse text strings into useful forms for Tk.  This file has
 *	the simpler procedures, like Tk_GetDirection and Tk_GetUid.
 *	The more complex procedures like Tk_GetColor are in separate
 *	files.
 *
 * Copyright (c) 1991-1994 The Regents of the University of California.
 * Copyright (c) 1994-1995 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * SCCS: @(#) tkGet.c 1.13 96/04/26 10:25:46
 */

#include "tkInt.h"
#include "tkPort.h"

#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif
#ifndef NULL
#define NULL 0
#endif

static int maxExponent = 511;	/* Largest possible base 10 exponent.  Any
				 * exponent larger than this will already
				 * produce underflow or overflow, so there's
				 * no need to worry about additional digits.
				 */
static double powersOf10[] = {	/* Table giving binary powers of 10.  Entry */
    10.,			/* is 10^2^i.  Used to convert decimal */
    100.,			/* exponents into floating-point numbers. */
    1.0e4,
    1.0e8,
    1.0e16,
    1.0e32,
    1.0e64,
    1.0e128,
    1.0e256
};

static double mystrtod _ANSI_ARGS_((CONST char*,char** ));
/*
 *----------------------------------------------------------------------
 *
 * mystrtod --
 *
 *	This procedure converts a floating-point number from an ASCII
 *	decimal representation to internal double-precision format.
 *
 * Results:
 *	The return value is the double-precision floating-point
 *	representation of the characters in string.  If endPtr isn't
 *	NULL, then *endPtr is filled in with the address of the
 *	next character after the last one that was part of the
 *	floating-point number.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static double
mystrtod(string, endPtr)
    CONST char *string;		/* A decimal ASCII floating-point number,
				 * optionally preceded by white space.
				 * Must have form "-I.FE-X", where I is the
				 * integer part of the mantissa, F is the
				 * fractional part of the mantissa, and X
				 * is the exponent.  Either of the signs
				 * may be "+", "-", or omitted.  Either I
				 * or F may be omitted, or both.  The decimal
				 * point isn't necessary unless F is present.
				 * The "E" may actually be an "e".  E and X
				 * may both be omitted (but not just one).
				 */
    char **endPtr;		/* If non-NULL, store terminating character's
				 * address here. */
{
    int sign, expSign = FALSE;
    double fraction, dblExp, *d;
    register CONST char *p;
    register int c;
    int exp = 0;		/* Exponent read from "EX" field. */
    int fracExp = 0;		/* Exponent that derives from the fractional
				 * part.  Under normal circumstatnces, it is
				 * the negative of the number of digits in F.
				 * However, if I is very long, the last digits
				 * of I get dropped (otherwise a long I with a
				 * large negative exponent could cause an
				 * unnecessary overflow on I alone).  In this
				 * case, fracExp is incremented one for each
				 * dropped digit. */
    int mantSize;		/* Number of digits in mantissa. */
    int decPt;			/* Number of mantissa digits BEFORE decimal
				 * point. */
    CONST char *pExp;		/* Temporarily holds location of exponent
				 * in string. */

    /*
     * Strip off leading blanks and check for a sign.
     */

    p = string;
    while (isspace(*p)) {
	p += 1;
    }
    if (*p == '-') {
	sign = TRUE;
	p += 1;
    } else {
	if (*p == '+') {
	    p += 1;
	}
	sign = FALSE;
    }

    /*
     * Count the number of digits in the mantissa (including the decimal
     * point), and also locate the decimal point.
     */

    decPt = -1;
    for (mantSize = 0; ; mantSize += 1)
    {
	c = *p;
	if (!isdigit(c)) {
	    if ((c != '.') || (decPt >= 0)) {
		break;
	    }
	    decPt = mantSize;
	}
	p += 1;
    }

    /*
     * Now suck up the digits in the mantissa.  Use two integers to
     * collect 9 digits each (this is faster than using floating-point).
     * If the mantissa has more than 18 digits, ignore the extras, since
     * they can't affect the value anyway.
     */
    
    pExp  = p;
    p -= mantSize;
    if (decPt < 0) {
	decPt = mantSize;
    } else {
	mantSize -= 1;			/* One of the digits was the point. */
    }
    if (mantSize > 18) {
	fracExp = decPt - 18;
	mantSize = 18;
    } else {
	fracExp = decPt - mantSize;
    }
    if (mantSize == 0) {
	fraction = 0.0;
	p = string;
	goto done;
    } else {
	int frac1, frac2;
	frac1 = 0;
	for ( ; mantSize > 9; mantSize -= 1)
	{
	    c = *p;
	    p += 1;
	    if (c == '.') {
		c = *p;
		p += 1;
	    }
	    frac1 = 10*frac1 + (c - '0');
	}
	frac2 = 0;
	for (; mantSize > 0; mantSize -= 1)
	{
	    c = *p;
	    p += 1;
	    if (c == '.') {
		c = *p;
		p += 1;
	    }
	    frac2 = 10*frac2 + (c - '0');
	}
	fraction = (1.0e9 * frac1) + frac2;
    }

    /*
     * Skim off the exponent.
     */

    p = pExp;
    if ((*p == 'E') || (*p == 'e')) {
	p += 1;
	if (*p == '-') {
	    expSign = TRUE;
	    p += 1;
	} else {
	    if (*p == '+') {
		p += 1;
	    }
	    expSign = FALSE;
	}
	while (isdigit(*p)) {
	    exp = exp * 10 + (*p - '0');
	    p += 1;
	}
    }
    if (expSign) {
	exp = fracExp - exp;
    } else {
	exp = fracExp + exp;
    }

    /*
     * Generate a floating-point number that represents the exponent.
     * Do this by processing the exponent one bit at a time to combine
     * many powers of 2 of 10. Then combine the exponent with the
     * fraction.
     */
    
    if (exp < 0) {
	expSign = TRUE;
	exp = -exp;
    } else {
	expSign = FALSE;
    }
    if (exp > maxExponent) {
	exp = maxExponent;
    }
    dblExp = 1.0;
    for (d = powersOf10; exp != 0; exp >>= 1, d += 1) {
	if (exp & 01) {
	    dblExp *= *d;
	}
    }
    if (expSign) {
	fraction /= dblExp;
    } else {
	fraction *= dblExp;
    }

done:
    if (endPtr != NULL) {
	*endPtr = (char *) p;
    }

    if (sign) {
	return -fraction;
    }
    return fraction;
}

/*
 * The hash table below is used to keep track of all the Tk_Uids created
 * so far.
 */

static Tcl_HashTable uidTable;
static int initialized = 0;

/*
 *--------------------------------------------------------------
 *
 * Tk_GetAnchor --
 *
 *	Given a string, return the corresponding Tk_Anchor.
 *
 * Results:
 *	The return value is a standard Tcl return result.  If
 *	TCL_OK is returned, then everything went well and the
 *	position is stored at *anchorPtr;  otherwise TCL_ERROR
 *	is returned and an error message is left in
 *	interp->result.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

int
Tk_GetAnchor(interp, string, anchorPtr)
    Tcl_Interp *interp;		/* Use this for error reporting. */
    char *string;		/* String describing a direction. */
    Tk_Anchor *anchorPtr;	/* Where to store Tk_Anchor corresponding
				 * to string. */
{
    switch (string[0]) {
	case 'n':
	    if (string[1] == 0) {
		*anchorPtr = TK_ANCHOR_N;
		return TCL_OK;
	    } else if ((string[1] == 'e') && (string[2] == 0)) {
		*anchorPtr = TK_ANCHOR_NE;
		return TCL_OK;
	    } else if ((string[1] == 'w') && (string[2] == 0)) {
		*anchorPtr = TK_ANCHOR_NW;
		return TCL_OK;
	    }
	    goto error;
	case 's':
	    if (string[1] == 0) {
		*anchorPtr = TK_ANCHOR_S;
		return TCL_OK;
	    } else if ((string[1] == 'e') && (string[2] == 0)) {
		*anchorPtr = TK_ANCHOR_SE;
		return TCL_OK;
	    } else if ((string[1] == 'w') && (string[2] == 0)) {
		*anchorPtr = TK_ANCHOR_SW;
		return TCL_OK;
	    } else {
		goto error;
	    }
	case 'e':
	    if (string[1] == 0) {
		*anchorPtr = TK_ANCHOR_E;
		return TCL_OK;
	    }
	    goto error;
	case 'w':
	    if (string[1] == 0) {
		*anchorPtr = TK_ANCHOR_W;
		return TCL_OK;
	    }
	    goto error;
	case 'c':
	    if (strncmp(string, "center", strlen(string)) == 0) {
		*anchorPtr = TK_ANCHOR_CENTER;
		return TCL_OK;
	    }
	    goto error;
    }

    error:
    Tcl_AppendResult(interp, "bad anchor position \"", string,
	    "\": must be n, ne, e, se, s, sw, w, nw, or center",
	    (char *) NULL);
    return TCL_ERROR;
}

/*
 *--------------------------------------------------------------
 *
 * Tk_NameOfAnchor --
 *
 *	Given a Tk_Anchor, return the string that corresponds
 *	to it.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

char *
Tk_NameOfAnchor(anchor)
    Tk_Anchor anchor;		/* Anchor for which identifying string
				 * is desired. */
{
    switch (anchor) {
	case TK_ANCHOR_N: return "n";
	case TK_ANCHOR_NE: return "ne";
	case TK_ANCHOR_E: return "e";
	case TK_ANCHOR_SE: return "se";
	case TK_ANCHOR_S: return "s";
	case TK_ANCHOR_SW: return "sw";
	case TK_ANCHOR_W: return "w";
	case TK_ANCHOR_NW: return "nw";
	case TK_ANCHOR_CENTER: return "center";
    }
    return "unknown anchor position";
}

/*
 *--------------------------------------------------------------
 *
 * Tk_GetJoinStyle --
 *
 *	Given a string, return the corresponding Tk_JoinStyle.
 *
 * Results:
 *	The return value is a standard Tcl return result.  If
 *	TCL_OK is returned, then everything went well and the
 *	justification is stored at *joinPtr;  otherwise
 *	TCL_ERROR is returned and an error message is left in
 *	interp->result.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

int
Tk_GetJoinStyle(interp, string, joinPtr)
    Tcl_Interp *interp;		/* Use this for error reporting. */
    char *string;		/* String describing a justification style. */
    int *joinPtr;		/* Where to store join style corresponding
				 * to string. */
{
    int c;
    size_t length;