/*
 * Copyright (c) 1984 through 2008, William LeFebvre
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 * 
 *     * Neither the name of William LeFebvre nor the names of other
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 *  Top users/processes display for Unix
 *  Version 3
 */

/*
 *  This file contains various handy utilities used by top.
 */

#include "os.h"
#include <ctype.h>
#ifdef HAVE_STDARG_H
#include <stdarg.h>
#else
#undef DEBUG
#endif
#include "top.h"
#include "utils.h"

static int
alldigits(char *s)

{
    int ch;

    while ((ch = *s++) != '\0')
    {
	if (!isdigit(ch))
	{
	    return 0;
	}
    }
    return 1;
}

int
atoiwi(char *str)

{
    register int len;

    len = strlen(str);
    if (len != 0)
    {
	if (strncmp(str, "infinity", len) == 0 ||
	    strncmp(str, "all",      len) == 0 ||
	    strncmp(str, "maximum",  len) == 0)
	{
	    return(Infinity);
	}
	else if (alldigits(str))
	{
	    return(atoi(str));
	}
	else
	{
	    return(Invalid);
	}
    }
    return(0);
}

/*
 *  itoa - convert integer (decimal) to ascii string for positive numbers
 *  	   only (we don't bother with negative numbers since we know we
 *	   don't use them).
 */

				/*
				 * How do we know that 16 will suffice?
				 * Because the biggest number that we will
				 * ever convert will be 2^32-1, which is 10
				 * digits.
				 */

char *
itoa(int val)

{
    register char *ptr;
    static char buffer[16];	/* result is built here */
    				/* 16 is sufficient since the largest number
				   we will ever convert will be 2^32-1,
				   which is 10 digits. */

    ptr = buffer + sizeof(buffer);
    *--ptr = '\0';
    if (val == 0)
    {
	*--ptr = '0';
    }
    else while (val != 0)
    {
	*--ptr = (val % 10) + '0';
	val /= 10;
    }
    return(ptr);
}

/*
 *  itoa7(val) - like itoa, except the number is right justified in a 7
 *	character field.  This code is a duplication of itoa instead of
 *	a front end to a more general routine for efficiency.
 */

char *
itoa_w(int val, int w)

{
    char *ptr;
    char *eptr;
    static char buffer[16];	/* result is built here */
    				/* 16 is sufficient since the largest number
				   we will ever convert will be 2^32-1,
				   which is 10 digits. */

    if (w > 15)
    {
	w = 15;
    }
    eptr = ptr = buffer + sizeof(buffer);
    *--ptr = '\0';
    if (val == 0)
    {
	*--ptr = '0';
    }
    else while (val != 0)
    {
	*--ptr = (val % 10) + '0';
	val /= 10;
    }
    while (ptr >= eptr - w)
    {
	*--ptr = ' ';
    }
    return(ptr);
}

char *
itoa7(int val)

{
    return itoa_w(val, 7);
}

/*
 *  digits(val) - return number of decimal digits in val.  Only works for
 *	positive numbers.  If val < 0 then digits(val) == 0, but
 *      digits(0) == 1.
 */

int
digits(int val)

{
    register int cnt = 0;

    if (val == 0)
    {
	return 1;
    }
    while (val > 0)
    {
	cnt++;
	val /= 10;
    }
    return(cnt);
}

/*
 *  printable(char *str) - make the string pointed to by "str" into one that is
 *	printable (i.e.: all ascii), by converting all non-printable
 *	characters into '?'.  Replacements are done in place and a pointer
 *	to the original buffer is returned.
 */

char *
printable(char *str)

{
    register char *ptr;
    register int ch;

    ptr = str;
    while ((ch = *ptr) != '\0')
    {
	if (!isprint(ch))
	{
	    *ptr = '?';
	}
	ptr++;
    }
    return(str);
}

/*
 *  strcpyend(to, from) - copy string "from" into "to" and return a pointer
 *	to the END of the string "to".
 */

char *
strcpyend(char *to, char *from)

{
    while ((*to++ = *from++) != '\0');
    return(--to);
}

/*
 * char *
 * homogenize(char *str)
 *
 * Remove unwanted characters from "str" and make everything lower case.
 * Newly allocated string is returned: the original is not altered.
 */

char *homogenize(char *str)

{
    char *ans;
    char *fr;
    char *to;
    int ch;

    to = fr = ans = strdup(str);
    while ((ch = *fr++) != '\0')
    {
	if (isalnum(ch))
	{
	    *to++ = tolower(ch);
	}
    }

    *to = '\0';
    return ans;
}

/*
 * string_index(string, array) - find string in array and return index
 */

int
string_index(char *string, char **array)

{
    register int i = 0;

    while (*array != NULL)
    {
	if (strcmp(string, *array) == 0)
	{
	    return(i);
	}
	array++;
	i++;
    }
    return(-1);
}

/*
 * char *string_list(char **strings)
 *
 * Create a comma-separated list of the strings in the NULL-terminated
 * "strings".  Returned string is malloc-ed and should be freed when the
 * caller is done.  Note that this is not an efficient function.
 */

char *string_list(char **strings)

{
    int cnt = 0;
    char **pp;
    char *p;
    char *result = NULL;
    char *resp = NULL;

    pp = strings;
    while ((p = *pp++) != NULL)
    {
	cnt += strlen(p) + 2;
    }

    if (cnt > 0)
    {
	resp = result = (char *)malloc(cnt);
	pp = strings;
	while ((p = *pp++) != NULL)
	{
	    resp = strcpyend(resp, p);
	    if (*pp != NULL)
	    {
		resp = strcpyend(resp, ", ");
	    }
	}
    }

    return result;
}

/*
 * argparse(line, cntp) - parse arguments in string "line", separating them
 *	out into an argv-like array, and setting *cntp to the number of
 *	arguments encountered.  This is a simple parser that doesn't understand
 *	squat about quotes.
 */

char **
argparse(char *line, int *cntp)

{
    register char *from;
    register char *to;
    register int cnt;
    register int ch;
    int length;
    int lastch;
    register char **argv;
    char **argarray;
    char *args;

    /* unfortunately, the only real way to do this is to go thru the
       input string twice. */

    /* step thru the string counting the white space sections */
    from = line;
    lastch = cnt = length = 0;
    while ((ch = *from++) != '\0')
    {
	length++;
	if (ch == ' ' && lastch != ' ')
	{
	    cnt++;
	}
	lastch = ch;
    }

    /* add three to the count:  one for the initial "dummy" argument,
       one for the last argument and one for NULL */
    cnt += 3;

    /* allocate a char * array to hold the pointers */
    argarray = (char **)malloc(cnt * sizeof(char *));

    /* allocate another array to hold the strings themselves */
    args = (char *)malloc(length+2);

    /* initialization for main loop */
    from = line;
    to = args;
    argv = argarray;
    lastch = '\0';

    /* create a dummy argument to keep getopt happy */
    *argv++ = to;
    *to++ = '\0';
    cnt = 2;

    /* now build argv while copying characters */
    *argv++ = to;
    while ((ch = *from++) != '\0')
    {
	if (ch != ' ')
	{
	    if (lastch == ' ')
	    {
		*to++ = '\0';
		*argv++ = to;
		cnt++;
	    }
	    *to++ = ch;
	}
	lastch = ch;
    }
    *to++ = '\0';

    /* set cntp and return the allocated array */
    *cntp = cnt;
    return(argarray);
}

/*
 *  percentages(cnt, out, new, old, diffs) - calculate percentage change
 *	between array "old" and "new", putting the percentages i "out".
 *	"cnt" is size of each array and "diffs" is used for scratch space.
 *	The array "old" is updated on each call.
 *	The routine assumes modulo arithmetic.  This function is especially
 *	useful on BSD mchines for calculating cpu state percentages.
 */

long
percentages(int cnt, int *out, long *new, long *old, long *diffs)

{
    register int i;
    register long change;
    register long total_change;
    register long *dp;
    long half_total;

    /* initialization */
    total_change = 0;
    dp = diffs;

    /* calculate changes for each state and the overall change */
    for (i = 0; i < cnt; i++)
    {
	if ((change = *new - *old) < 0)
	{
	    /* this only happens when the counter wraps */
	    change = (int)
		((unsigned long)*new-(unsigned long)*old);
	}
	total_change += (*dp++ = change);
	*old++ = *new++;
    }

    /* avoid divide by zero potential */
    if (total_change == 0)
    {
	total_change = 1;
    }

    /* calculate percentages based on overall change, rounding up */
    half_total = total_change / 2l;
    for (i = 0; i < cnt; i++)
    {
	*out++ = (int)((*diffs++ * 1000 + half_total) / total_change);
    }

    /* return the total in case the caller wants to use it */
    return(total_change);
}

/*
 * errmsg(errnum) - return an error message string appropriate to the
 *           error number "errnum".  This is a substitute for the System V
 *           function "strerror".  There appears to be no reliable way to
 *           determine if "strerror" exists at compile time, so I make do
 *           by providing something of similar functionality.  For those
 *           systems that have strerror and NOT errlist, define
 *           -DHAVE_STRERROR in the module file and this function will
 *           use strerror.
 */

/* externs referenced by errmsg */

#ifndef HAVE_STRERROR
#if !HAVE_DECL_SYS_ERRLIST
extern char *sys_errlist[];
#endif

extern int sys_nerr;
#endif

char *
errmsg(int errnum)

{
#ifdef HAVE_STRERROR
    char *msg = strerror(errnum);
    if (msg != NULL)
    {
	return msg;
    }
#else
    if (errnum > 0 && errnum < sys_nerr)
    {
	return((char *)(sys_errlist[errnum]));
    }
#endif
    return("No error");
}

/* format_percent(v) - format a double as a percentage in a manner that
 *		does not exceed 5 characters (excluding any trailing
 *		percent sign).  Since it is possible for the value
 *		to exceed 100%, we format such values with no fractional
 *		component to fit within the 5 characters.
 */

char *
format_percent(double v)

{
    static char result[10];

    /* enumerate the possibilities */
    if (v < 0 || v >= 100000.)
    {
	/* we dont want to try extreme values */
	strcpy(result, "  ???");
    }
    else if (v > 99.99)
    {
	sprintf(result, "%5.0f", v);
    }
    else
    {
	sprintf(result, "%5.2f", v);
    }

    return result;
}

/* format_time(seconds) - format number of seconds into a suitable
 *		display that will fit within 6 characters.  Note that this
 *		routine builds its string in a static area.  If it needs
 *		to be called more than once without overwriting previous data,
 *		then we will need to adopt a technique similar to the
 *		one used for format_k.
 */

/* Explanation:
   We want to keep the output within 6 characters.  For low values we use
   the format mm:ss.  For values that exceed 999:59, we switch to a format
   that displays hours and fractions:  hhh.tH.  For values that exceed
   999.9, we use hhhh.t and drop the "H" designator.  For values that
   exceed 9999.9, we use "???".
 */

void *
format_time(long seconds, char *result, int len)

{
    /* sanity protection */
    if (seconds < 0 || seconds > (99999l * 360l))
    {
	strcpy(result, "   ???");
    }
    else if (seconds >= (1000l * 60l))
    {
	/* alternate (slow) method displaying hours and tenths */
	snprintf(result, len - 1, "%5.1fH", (double)seconds / (double)(60l * 60l));

	/* It is possible that the sprintf took more than 6 characters.
	   If so, then the "H" appears as result[6].  If not, then there
	   is a \0 in result[6].  Either way, it is safe to step on.
	 */
	if (len / sizeof(result[0]) > 6)
	    result[6] = '\0';
    }
    else
    {
	/* standard method produces MMM:SS */
	/* we avoid printf as must as possible to make this quick */
	snprintf(result, len - 1, "%3ld:%02ld", seconds / 60l, seconds % 60l);
    }
    return(result);
}

/*
 * format_k(amt) - format a kilobyte memory value, returning a string
 *		suitable for display.  Returns a pointer to a static
 *		area that changes each call.  "amt" is converted to a
 *		string with a trailing "K".  If "amt" is 10000 or greater,
 *		then it is formatted as megabytes (rounded) with a
 *		trailing "M".
 */

/*
 * Compromise time.  We need to return a string, but we don't want the
 * caller to have to worry about freeing a dynamically allocated string.
 * Unfortunately, we can't just return a pointer to a static area as one
 * of the common uses of this function is in a large call to sprintf where
 * it might get invoked several times.  Our compromise is to maintain an
 * array of strings and cycle thru them with each invocation.  We make the
 * array large enough to handle the above mentioned case.  The constant
 * NUM_STRINGS defines the number of strings in this array:  we can tolerate
 * up to NUM_STRINGS calls before we start overwriting old information.
 * Keeping NUM_STRINGS a power of two will allow an intelligent optimizer
 * to convert the modulo operation into something quicker.  What a hack!
 */

#define NUM_STRINGS 8

char *
format_k(long amt)

{
    static char retarray[NUM_STRINGS][16];
    static int index = 0;
    register char *ret;
    register char tag = 'K';

    ret = retarray[index];
    index = (index + 1) % NUM_STRINGS;

    if (amt >= 10000)
    {
	amt = (amt + 512) / 1024;
	tag = 'M';
	if (amt >= 10000)
	{
	    amt = (amt + 512) / 1024;
	    tag = 'G';
	}
    }

    snprintf(ret, sizeof(retarray[index])-1, "%ld%c", amt, tag);

    return(ret);
}

/*
 * Time keeping functions.  
 */

static struct timeval lasttime = { 0, 0 };
static unsigned int elapsed_msecs = 0;

void
time_get(struct timeval *tv)

{
    /* get the current time */
#ifdef HAVE_GETTIMEOFDAY
    gettimeofday(tv, NULL);
#else
    tv->tv_sec = (long)time(NULL);
    tv->tv_usec = 0;
#endif
}

void
time_mark(struct timeval *tv)

{
    struct timeval thistime;
    struct timeval timediff;

    /* if the caller didnt provide one then use our own */
    if (tv == NULL)
    {
	tv = &thistime;
    }

    /* get the current time */
#ifdef HAVE_GETTIMEOFDAY
    gettimeofday(tv, NULL);
#else
    tv->tv_sec = (long)time(NULL);
    tv->tv_usec = 0;
#endif

    /* calculate the difference */
    timediff.tv_sec = tv->tv_sec - lasttime.tv_sec;
    timediff.tv_usec = tv->tv_usec - lasttime.tv_usec;
    if (timediff.tv_usec < 0) {
	timediff.tv_sec--;
	timediff.tv_usec += 1000000;
    }

    /* convert to milliseconds */
    elapsed_msecs = timediff.tv_sec * 1000 + timediff.tv_usec / 1000;
    if (elapsed_msecs == 0)
    {
	elapsed_msecs = 1;
    }

    /* save for next time */
    lasttime = *tv;
}

unsigned int
time_elapsed()

{
    return elapsed_msecs;
}

unsigned int
diff_per_second(unsigned int x, unsigned int y)

{
    return (y > x ? UINT_MAX - y + x + 1 : x - y) * 1000 / elapsed_msecs;
}

static int debug_on = 0;

#ifdef DEBUG
FILE *debugfile;
#endif

void
debug_set(int i)

{
    debug_on = i;
#ifdef DEBUG
    debugfile = fopen("/tmp/top.debug", "w");
#endif
}

#ifdef DEBUG
void
xdprintf(char *fmt, ...)

{
    va_list argp;

    va_start(argp, fmt);

    if (debug_on)
    {
	vfprintf(debugfile, fmt, argp);
	fflush(debugfile);
    }

    va_end(argp);
}
#endif