root/src/xz/util.c

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DEFINITIONS

This source file includes following definitions.
  1. xrealloc
  2. xstrdup
  3. str_to_uint64
  4. round_up_to_mib
  5. check_thousand_sep
  6. uint64_to_str
  7. uint64_to_nicestr
  8. my_snprintf
  9. is_empty_filename
  10. is_tty_stdin
  11. is_tty_stdout

///////////////////////////////////////////////////////////////////////////////
//
/// \file       util.c
/// \brief      Miscellaneous utility functions
//
//  Author:     Lasse Collin
//
//  This file has been put into the public domain.
//  You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////

#include "private.h"
#include <stdarg.h>


/// Buffers for uint64_to_str() and uint64_to_nicestr()
static char bufs[4][128];

/// Thousand separator support in uint64_to_str() and uint64_to_nicestr()
static enum { UNKNOWN, WORKS, BROKEN } thousand = UNKNOWN;


extern void *
xrealloc(void *ptr, size_t size)
{
        assert(size > 0);

        ptr = realloc(ptr, size);
        if (ptr == NULL)
                message_fatal("%s", strerror(errno));

        return ptr;
}


extern char *
xstrdup(const char *src)
{
        assert(src != NULL);
        const size_t size = strlen(src) + 1;
        char *dest = xmalloc(size);
        return memcpy(dest, src, size);
}


extern uint64_t
str_to_uint64(const char *name, const char *value, uint64_t min, uint64_t max)
{
        uint64_t result = 0;

        // Skip blanks.
        while (*value == ' ' || *value == '\t')
                ++value;

        // Accept special value "max". Supporting "min" doesn't seem useful.
        if (strcmp(value, "max") == 0)
                return max;

        if (*value < '0' || *value > '9')
                message_fatal(_("%s: Value is not a non-negative "
                                "decimal integer"), value);

        do {
                // Don't overflow.
                if (result > UINT64_MAX / 10)
                        goto error;

                result *= 10;

                // Another overflow check
                const uint32_t add = *value - '0';
                if (UINT64_MAX - add < result)
                        goto error;

                result += add;
                ++value;
        } while (*value >= '0' && *value <= '9');

        if (*value != '\0') {
                // Look for suffix. Originally this supported both base-2
                // and base-10, but since there seems to be little need
                // for base-10 in this program, treat everything as base-2
                // and also be more relaxed about the case of the first
                // letter of the suffix.
                uint64_t multiplier = 0;
                if (*value == 'k' || *value == 'K')
                        multiplier = UINT64_C(1) << 10;
                else if (*value == 'm' || *value == 'M')
                        multiplier = UINT64_C(1) << 20;
                else if (*value == 'g' || *value == 'G')
                        multiplier = UINT64_C(1) << 30;

                ++value;

                // Allow also e.g. Ki, KiB, and KB.
                if (*value != '\0' && strcmp(value, "i") != 0
                                && strcmp(value, "iB") != 0
                                && strcmp(value, "B") != 0)
                        multiplier = 0;

                if (multiplier == 0) {
                        message(V_ERROR, _("%s: Invalid multiplier suffix"),
                                        value - 1);
                        message_fatal(_("Valid suffixes are `KiB' (2^10), "
                                        "`MiB' (2^20), and `GiB' (2^30)."));
                }

                // Don't overflow here either.
                if (result > UINT64_MAX / multiplier)
                        goto error;

                result *= multiplier;
        }

        if (result < min || result > max)
                goto error;

        return result;

error:
        message_fatal(_("Value of the option `%s' must be in the range "
                                "[%" PRIu64 ", %" PRIu64 "]"),
                                name, min, max);
}


extern uint64_t
round_up_to_mib(uint64_t n)
{
        return (n >> 20) + ((n & ((UINT32_C(1) << 20) - 1)) != 0);
}


/// Check if thousand separator is supported. Run-time checking is easiest,
/// because it seems to be sometimes lacking even on POSIXish system.
static void
check_thousand_sep(uint32_t slot)
{
        if (thousand == UNKNOWN) {
                bufs[slot][0] = '\0';
                snprintf(bufs[slot], sizeof(bufs[slot]), "%'u", 1U);
                thousand = bufs[slot][0] == '1' ? WORKS : BROKEN;
        }

        return;
}


extern const char *
uint64_to_str(uint64_t value, uint32_t slot)
{
        assert(slot < ARRAY_SIZE(bufs));

        check_thousand_sep(slot);

        if (thousand == WORKS)
                snprintf(bufs[slot], sizeof(bufs[slot]), "%'" PRIu64, value);
        else
                snprintf(bufs[slot], sizeof(bufs[slot]), "%" PRIu64, value);

        return bufs[slot];
}


extern const char *
uint64_to_nicestr(uint64_t value, enum nicestr_unit unit_min,
                enum nicestr_unit unit_max, bool always_also_bytes,
                uint32_t slot)
{
        assert(unit_min <= unit_max);
        assert(unit_max <= NICESTR_TIB);
        assert(slot < ARRAY_SIZE(bufs));

        check_thousand_sep(slot);

        enum nicestr_unit unit = NICESTR_B;
        char *pos = bufs[slot];
        size_t left = sizeof(bufs[slot]);

        if ((unit_min == NICESTR_B && value < 10000)
                        || unit_max == NICESTR_B) {
                // The value is shown as bytes.
                if (thousand == WORKS)
                        my_snprintf(&pos, &left, "%'u", (unsigned int)value);
                else
                        my_snprintf(&pos, &left, "%u", (unsigned int)value);
        } else {
                // Scale the value to a nicer unit. Unless unit_min and
                // unit_max limit us, we will show at most five significant
                // digits with one decimal place.
                double d = (double)(value);
                do {
                        d /= 1024.0;
                        ++unit;
                } while (unit < unit_min || (d > 9999.9 && unit < unit_max));

                if (thousand == WORKS)
                        my_snprintf(&pos, &left, "%'.1f", d);
                else
                        my_snprintf(&pos, &left, "%.1f", d);
        }

        static const char suffix[5][4] = { "B", "KiB", "MiB", "GiB", "TiB" };
        my_snprintf(&pos, &left, " %s", suffix[unit]);

        if (always_also_bytes && value >= 10000) {
                if (thousand == WORKS)
                        snprintf(pos, left, " (%'" PRIu64 " B)", value);
                else
                        snprintf(pos, left, " (%" PRIu64 " B)", value);
        }

        return bufs[slot];
}


extern void
my_snprintf(char **pos, size_t *left, const char *fmt, ...)
{
        va_list ap;
        va_start(ap, fmt);
        const int len = vsnprintf(*pos, *left, fmt, ap);
        va_end(ap);

        // If an error occurred, we want the caller to think that the whole
        // buffer was used. This way no more data will be written to the
        // buffer. We don't need better error handling here, although it
        // is possible that the result looks garbage on the terminal if
        // e.g. an UTF-8 character gets split. That shouldn't (easily)
        // happen though, because the buffers used have some extra room.
        if (len < 0 || (size_t)(len) >= *left) {
                *left = 0;
        } else {
                *pos += len;
                *left -= len;
        }

        return;
}


extern bool
is_empty_filename(const char *filename)
{
        if (filename[0] == '\0') {
                message_error(_("Empty filename, skipping"));
                return true;
        }

        return false;
}


extern bool
is_tty_stdin(void)
{
        const bool ret = isatty(STDIN_FILENO);

        if (ret)
                message_error(_("Compressed data cannot be read from "
                                "a terminal"));

        return ret;
}


extern bool
is_tty_stdout(void)
{
        const bool ret = isatty(STDOUT_FILENO);

        if (ret)
                message_error(_("Compressed data cannot be written to "
                                "a terminal"));

        return ret;
}

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