SysIII/usr/src/lib/libc/pdp11/stdio/_print.h
/*
* _print: common code for printf, fprintf, sprintf
* Floating-point code is included or not, depending
* on whether the preprocessor variable FLOAT is 1 or 0.
*/
#include <stdio.h>
#include <ctype.h>
#include <varargs.h>
#include "param.h"
#define max(a,b) ((a) > (b)? (a): (b))
#define min(a,b) ((a) < (b)? (a): (b))
/* If this symbol is nonzero, allow '0' as a flag */
#define FZERO 1
/*
* The following two variables are set by our caller,
* and used in emitchar. If our caller is sprintf, _pfile
* will be gimmicked up so that putc will put the
* outgoing characters in the right place.
*/
FILE *_pfile;
#if FLOAT
/*
* System-supplied routines for floating conversion
*/
char *fcvt();
char *ecvt();
#endif
/* This variable counts output characters. */
static int count;
int _print (format, args)
char *format;
va_list *args;
{
/* Current position in format */
char *cp;
/* Starting and ending points for value to be printed */
char *bp, *p;
/* Field width and precision */
int width, prec;
/* Format code */
char fcode;
/* Number of padding zeroes required on the left */
int lzero;
/* Flags - nonzero if corresponding character appears in format */
bool length; /* l */
bool fplus; /* + */
bool fminus; /* - */
bool fblank; /* blank */
bool fsharp; /* # */
#if FZERO
bool fzero; /* 0 */
#endif
/* Pointer to sign, "0x", "0X", or empty */
char *prefix;
#if FLOAT
/* Exponent or empty */
char *suffix;
/* Buffer to create exponent */
char expbuf[MAXESIZ + 1];
/* Number of padding zeroes required on the right */
int rzero;
/* The value being converted, if real */
double dval;
/* Output values from fcvt and ecvt */
int decpt, sign;
/* Scratch */
int k;
/* Values are developed in this buffer */
char buf[max (MAXDIGS, max (MAXFCVT + MAXEXP, MAXECVT) + 1)];
#else
char buf[MAXDIGS];
#endif
/* The value being converted, if integer */
long val;
/* Set to point to a translate table for digits of whatever radix */
char *tab;
/* Work variables */
int n, hradix, lowbit;
cp = format;
count = 0;
/*
* The main loop -- this loop goes through one iteration
* for each ordinary character or format specification.
*/
while (*cp)
if (*cp != '%') {
/* Ordinary (non-%) character */
putc (*cp++, _pfile);
++count;
} else {
/*
* % has been found.
* First, parse the format specification.
*/
/* Scan the <flags> */
fplus = fminus = fblank = fsharp = 0;
#if FZERO
fzero = 0;
#endif
scan: switch (*++cp) {
case '+':
fplus = 1;
goto scan;
case '-':
fminus = 1;
goto scan;
case ' ':
fblank = 1;
goto scan;
case '#':
fsharp = 1;
goto scan;
#if FZERO
case '0':
fzero = 1;
goto scan;
#endif
}
/* Scan the field width */
if (*cp == '*') {
width = va_arg (*args, int);
if (width < 0) {
width = -width;
fminus = 1;
}
cp++;
} else {
width = 0;
while (isdigit (*cp)) {
n = tonumber (*cp++);
width = width * 10 + n;
}
}
/* Scan the precision */
if (*cp == '.') {
/* '*' instead of digits? */
if (*++cp == '*') {
prec = va_arg (*args, int);
cp++;
} else {
prec = 0;
while (isdigit (*cp)) {
n = tonumber (*cp++);
prec = prec * 10 + n;
}
}
} else
prec = -1;
/* Scan the length modifier */
length = 0;
switch (*cp) {
case 'l':
length = 1;
/* No break */
case 'h':
cp++;
}
/*
* The character addressed by cp must be the
* format letter -- there is nothing left for
* it to be.
*
* The status of the +, -, #, blank, and 0
* flags are reflected in the variables
* "fplus", "fminus", "fsharp", "fblank",
* and "fzero", respectively.
* "width" and "prec" contain numbers
* corresponding to the digit strings
* before and after the decimal point,
* respectively. If there was no decimal
* point, "prec" is -1.
*
* The following switch sets things up
* for printing. What ultimately gets
* printed will be padding blanks, a prefix,
* left padding zeroes, a value, right padding
* zeroes, a suffix, and more padding
* blanks. Padding blanks will not appear
* simultaneously on both the left and the
* right. Each case in this switch will
* compute the value, and leave in several
* variables the information necessary to
* construct what is to be printed.
*
* The prefix is a sign, a blank, "0x", "0X",
* or null, and is addressed by "prefix".
*
* The suffix is either null or an exponent,
* and is addressed by "suffix".
*
* The value to be printed starts at "bp"
* and continues up to and not including "p".
*
* "lzero" and "rzero" will contain the number
* of padding zeroes required on the left
* and right, respectively. If either of
* these variables is negative, it will be
* treated as if it were zero.
*
* The number of padding blanks, and whether
* they go on the left or the right, will be
* computed on exit from the switch.
*/
lzero = 0;
prefix = "";
#if FLOAT
rzero = lzero;
suffix = prefix;
#endif
switch (fcode = *cp++) {
/*
* fixed point representations
*
* "hradix" is half the radix for the conversion.
* Conversion is unsigned unless fcode is 'd'.
* HIBIT is 1000...000 binary, and is equal to
* the maximum negative number.
* We assume a 2's complement machine
*/
case 'd':
case 'u':
hradix = 5;
goto fixed;
case 'o':
hradix = 4;
goto fixed;
case 'X':
case 'x':
hradix = 8;
fixed:
/* Establish default precision */
if (prec < 0)
prec = 1;
/* Fetch the argument to be printed */
if (length)
val = va_arg (*args, long);
else if (fcode == 'd')
val = va_arg (*args, int);
else
val = va_arg (*args, unsigned);
/* If signed conversion, establish sign */
if (fcode == 'd') {
if (val < 0) {
prefix = "-";
/*
* Negate, checking in
* advance for possible
* overflow.
*/
if (val != HIBIT)
val = -val;
} else if (fplus)
prefix = "+";
else if (fblank)
prefix = " ";
}
#if FZERO
if (fzero) {
int n = width - strlen (prefix);
if (n > prec)
prec = n;
}
#endif
/* Set translate table for digits */
if (fcode == 'X')
tab = "0123456789ABCDEF";
else
tab = "0123456789abcdef";
/* Develop the digits of the value */
p = bp = buf + MAXDIGS;
while (val) {
lowbit = val & 1;
val = (val >> 1) & ~HIBIT;
*--bp = tab[val % hradix * 2 + lowbit];
val /= hradix;
}
/* Calculate padding zero requirement */
lzero = bp - p + prec;
/* Handle the # flag */
if (fsharp && bp != p)
switch (fcode) {
case 'o':
if (lzero < 1)
lzero = 1;
break;
case 'x':
prefix = "0x";
break;
case 'X':
prefix = "0X";
break;
}
break;
#if FLOAT
case 'E':
case 'e':
/*
* E-format. The general strategy
* here is fairly easy: we take
* what ecvt gives us and re-format it.
*/
/* Establish default precision */
if (prec < 0)
prec = 6;
/* Fetch the value */
dval = va_arg (*args, double);
/* Develop the mantissa */
bp = ecvt (dval,
min (prec + 1, MAXECVT),
&decpt,
&sign);
/* Determine the prefix */
e_merge:
if (sign)
prefix = "-";
else if (fplus)
prefix = "+";
else if (fblank)
prefix = " ";
/* Place the first digit in the buffer */
p = &buf[0];
*p++ = *bp != '\0'? *bp++: '0';
/* Put in a decimal point if needed */
if (prec != 0 || fsharp)
*p++ = '.';
/* Create the rest of the mantissa */
rzero = prec;
while (rzero > 0 && *bp!= '\0') {
--rzero;
*p++ = *bp++;
}
bp = &buf[0];
/* Create the exponent */
suffix = &expbuf[MAXESIZ];
*suffix = '\0';
if (dval != 0) {
n = decpt - 1;
if (n < 0)
n = -n;
while (n != 0) {
*--suffix = todigit (n % 10);
n /= 10;
}
}
/* Prepend leading zeroes to the exponent */
while (suffix > &expbuf[MAXESIZ - 2])
*--suffix = '0';
/* Put in the exponent sign */
*--suffix = (decpt > 0 || dval == 0)? '+': '-';
/* Put in the e */
*--suffix = isupper(fcode)? 'E' : 'e';
break;
case 'f':
/*
* F-format floating point. This is
* a good deal less simple than E-format.
* The overall strategy will be to call
* fcvt, reformat its result into buf,
* and calculate how many trailing
* zeroes will be required. There will
* never be any leading zeroes needed.
*/
/* Establish default precision */
if (prec < 0)
prec = 6;
/* Fetch the value */
dval = va_arg (*args, double);
/* Do the conversion */
bp = fcvt (dval,
min (prec, MAXFCVT),
&decpt,
&sign);
/* Determine the prefix */
f_merge:
if (sign && decpt > -prec &&
*bp != '\0' && *bp != '0')
prefix = "-";
else if (fplus)
prefix = "+";
else if (fblank)
prefix = " ";
/* Initialize buffer pointer */
p = &buf[0];
/* Emit the digits before the decimal point */
n = decpt;
k = 0;
if (n <= 0)
*p++ = '0';
else
do if (*bp == '\0' || k >= MAXFSIG)
*p++ = '0';
else {
*p++ = *bp++;
++k;
}
while (--n != 0);
/* Decide whether we need a decimal point */
if (fsharp || prec > 0)
*p++ = '.';
/* Digits (if any) after the decimal point */
n = min (prec, MAXFCVT);
rzero = prec - n;
while (--n >= 0)
if (++decpt <= 0
|| *bp == '\0'
|| k >= MAXFSIG)
*p++ = '0';
else {
*p++ = *bp++;
++k;
}
bp = &buf[0];
break;
case 'G':
case 'g':
/*
* g-format. We play around a bit
* and then jump into e or f, as needed.
*/
/* Establish default precision */
if (prec < 0)
prec = 6;
/* Fetch the value */
dval = va_arg (*args, double);
/* Do the conversion */
bp = ecvt (dval,
min (prec, MAXECVT),
&decpt,
&sign);
if (dval == 0)
decpt = 1;
k = prec;
if (!fsharp) {
n = strlen (bp);
if (n < k)
k = n;
while (k >= 1 && bp[k-1] == '0')
--k;
}
if (decpt < -3 || decpt > prec) {
prec = k - 1;
goto e_merge;
} else {
prec = k - decpt;
goto f_merge;
}
#endif
case 'c':
buf[0] = va_arg (*args, int);
bp = &buf[0];
p = bp + 1;
break;
case 's':
bp = va_arg (*args, char *);
if (prec < 0)
prec = MAXINT;
for (n=0; *bp++ != '\0' && n < prec; n++);
p = --bp;
bp -= n;
break;
case '\0':
cp--;
break;
/* case '%': */
default:
p = bp = &fcode;
p++;
break;
}
if (fcode != '\0') {
/* Calculate number of padding blanks */
int nblank;
nblank = width
#if FLOAT
- (rzero < 0? 0: rzero)
- strlen (suffix)
#endif
- (p - bp)
- (lzero < 0? 0: lzero)
- strlen (prefix);
/* Blanks on left if required */
if (!fminus)
while (--nblank >= 0)
emitchar (' ');
/* Prefix, if any */
while (*prefix != '\0')
emitchar (*prefix++);
/* Zeroes on the left */
while (--lzero >= 0)
emitchar ('0');
/* The value itself */
while (bp < p)
emitchar (*bp++);
#if FLOAT
/* Zeroes on the right */
while (--rzero >= 0)
emitchar ('0');
/* The suffix */
while (*suffix != '\0')
emitchar (*suffix++);
#endif
/* Blanks on the right if required */
if (fminus)
while (--nblank >= 0)
emitchar (' ');
}
}
return (_pfile != NULL && ferror (_pfile))? EOF: count;
}
/* Send a character to the output */
static
emitchar (c)
char c;
{
putc (c, _pfile);
++count;
}