wireshark/wsutil/to_str.c

/* wsutil/to_str.c
 * Routines for utilities to convert various other types to strings.
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <stdio.h>
#include <string.h>
#include <time.h>
#include <glib.h>

#include "to_str.h"

#include <wsutil/utf8_entities.h>
#include <wsutil/wslog.h>


static const char fast_strings[][4] = {
	"0", "1", "2", "3", "4", "5", "6", "7",
	"8", "9", "10", "11", "12", "13", "14", "15",
	"16", "17", "18", "19", "20", "21", "22", "23",
	"24", "25", "26", "27", "28", "29", "30", "31",
	"32", "33", "34", "35", "36", "37", "38", "39",
	"40", "41", "42", "43", "44", "45", "46", "47",
	"48", "49", "50", "51", "52", "53", "54", "55",
	"56", "57", "58", "59", "60", "61", "62", "63",
	"64", "65", "66", "67", "68", "69", "70", "71",
	"72", "73", "74", "75", "76", "77", "78", "79",
	"80", "81", "82", "83", "84", "85", "86", "87",
	"88", "89", "90", "91", "92", "93", "94", "95",
	"96", "97", "98", "99", "100", "101", "102", "103",
	"104", "105", "106", "107", "108", "109", "110", "111",
	"112", "113", "114", "115", "116", "117", "118", "119",
	"120", "121", "122", "123", "124", "125", "126", "127",
	"128", "129", "130", "131", "132", "133", "134", "135",
	"136", "137", "138", "139", "140", "141", "142", "143",
	"144", "145", "146", "147", "148", "149", "150", "151",
	"152", "153", "154", "155", "156", "157", "158", "159",
	"160", "161", "162", "163", "164", "165", "166", "167",
	"168", "169", "170", "171", "172", "173", "174", "175",
	"176", "177", "178", "179", "180", "181", "182", "183",
	"184", "185", "186", "187", "188", "189", "190", "191",
	"192", "193", "194", "195", "196", "197", "198", "199",
	"200", "201", "202", "203", "204", "205", "206", "207",
	"208", "209", "210", "211", "212", "213", "214", "215",
	"216", "217", "218", "219", "220", "221", "222", "223",
	"224", "225", "226", "227", "228", "229", "230", "231",
	"232", "233", "234", "235", "236", "237", "238", "239",
	"240", "241", "242", "243", "244", "245", "246", "247",
	"248", "249", "250", "251", "252", "253", "254", "255"
};

static inline char
low_nibble_of_octet_to_hex(guint8 oct)
{
	/* At least one version of Apple's C compiler/linker is buggy, causing
	   a complaint from the linker about the "literal C string section"
	   not ending with '\0' if we initialize a 16-element "char" array with
	   a 16-character string, the fact that initializing such an array with
	   such a string is perfectly legitimate ANSI C nonwithstanding, the 17th
	   '\0' byte in the string nonwithstanding. */
	static const gchar hex_digits[16] =
	{ '0', '1', '2', '3', '4', '5', '6', '7',
	  '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

	return hex_digits[oct & 0xF];
}

static inline char *
byte_to_hex(char *out, guint32 dword)
{
	*out++ = low_nibble_of_octet_to_hex(dword >> 4);
	*out++ = low_nibble_of_octet_to_hex(dword);
	return out;
}

/*
 * This does *not* null-terminate the string.  It returns a pointer
 * to the position in the string following the last character it
 * puts there, so that the caller can either put the null terminator
 * in or can append more stuff to the buffer.
 *
 * There needs to be at least len * 2 bytes left in the buffer.
 */
char *
bytes_to_hexstr(char *out, const guint8 *ad, size_t len)
{
	size_t i;

	ws_return_ptr_if_null(ad, NULL);

	for (i = 0; i < len; i++)
		out = byte_to_hex(out, ad[i]);
	return out;
}

/*
 * This does *not* null-terminate the string.  It returns a pointer
 * to the position in the string following the last character it
 * puts there, so that the caller can either put the null terminator
 * in or can append more stuff to the buffer.
 *
 * There needs to be at least len * 3 - 1 bytes left in the buffer.
 */
char *
bytes_to_hexstr_punct(char *out, const guint8 *ad, size_t len, char punct)
{
	size_t i;

	ws_return_ptr_if_null(ad, NULL);

	out = byte_to_hex(out, ad[0]);
	for (i = 1; i < len; i++) {
		*out++ = punct;
		out = byte_to_hex(out, ad[i]);
	}
	return out;
}

/* Routine to convert a sequence of bytes to a hex string, one byte/two hex
 * digits at at a time, with a specified punctuation character between
 * the bytes.
 *
 * If punct is '\0', no punctuation is applied (and thus
 * the resulting string is (len-1) bytes shorter)
 */
gchar *
bytes_to_str_punct_max(wmem_allocator_t *scope, const guint8 *ad, size_t len, const char punct, size_t max)
{
	gchar *buf;
	size_t buflen = len;
	gchar *buf_ptr;
	int truncated = 0;

	ws_return_str_if_zero(scope, len);
	ws_return_str_if_null(scope, ad);

	if (!punct)
		return bytes_to_str_max(scope, ad, len, max);

	if (max > len * 3)
		max = len * 3;

	buf=(gchar *)wmem_alloc(scope, max+3+1);
	if (buflen > max/3) {
		truncated = 1;
		buflen = max/3;
	}

	buf_ptr = bytes_to_hexstr_punct(buf, ad, buflen, punct); /* maximum max-1 bytes */

	if (truncated) {
		*buf_ptr++ = punct;			/* 1 byte */
		buf_ptr    = g_stpcpy(buf_ptr, UTF8_HORIZONTAL_ELLIPSIS);	/* 3 bytes */
	}

	*buf_ptr = '\0';
	return buf;
}

char *
bytes_to_str_max(wmem_allocator_t *scope, const guint8 *bd, size_t bd_len, size_t max)
{
	gchar *cur;
	gchar *cur_ptr;
	int truncated = 0;

	ws_return_str_if_zero(scope, bd_len);
	ws_return_str_if_null(scope, bd);

	if (max > bd_len * 2)
		max = bd_len * 2;

	cur=(gchar *)wmem_alloc(scope, max+3+1);
	if (bd_len > max/2) {
		truncated = 1;
		bd_len = max/2;
	}

	cur_ptr = bytes_to_hexstr(cur, bd, bd_len);	/* max MAX_BYTE_STR_LEN bytes */

	if (truncated)
		cur_ptr = g_stpcpy(cur_ptr, UTF8_HORIZONTAL_ELLIPSIS);	/* 3 bytes */

	*cur_ptr = '\0';				/* 1 byte */
	return cur;
}

/*
 * The *_to_str_back() functions measured approx. a x7.5 speed-up versus
 * snprintf() on my Linux system with GNU libc.
 */

char *
oct_to_str_back(char *ptr, guint32 value)
{
	while (value) {
		*(--ptr) = '0' + (value & 0x7);
		value >>= 3;
	}

	*(--ptr) = '0';
	return ptr;
}

char *
oct64_to_str_back(char *ptr, guint64 value)
{
	while (value) {
		*(--ptr) = '0' + (value & 0x7);
		value >>= 3;
	}

	*(--ptr) = '0';
	return ptr;
}

char *
hex_to_str_back_len(char *ptr, guint32 value, int len)
{
	do {
		*(--ptr) = low_nibble_of_octet_to_hex(value);
		value >>= 4;
		len--;
	} while (value);

	/* pad */
	while (len > 0) {
		*(--ptr) = '0';
		len--;
	}

	*(--ptr) = 'x';
	*(--ptr) = '0';

	return ptr;
}

char *
hex64_to_str_back_len(char *ptr, guint64 value, int len)
{
	do {
		*(--ptr) = low_nibble_of_octet_to_hex(value & 0xF);
		value >>= 4;
		len--;
	} while (value);

	/* pad */
	while (len > 0) {
		*(--ptr) = '0';
		len--;
	}

	*(--ptr) = 'x';
	*(--ptr) = '0';

	return ptr;
}

char *
uint_to_str_back(char *ptr, guint32 value)
{
	char const *p;

	/* special case */
	if (value == 0)
		*(--ptr) = '0';

	while (value >= 10) {
		p = fast_strings[100 + (value % 100)];

		value /= 100;

		*(--ptr) = p[2];
		*(--ptr) = p[1];
	}

	if (value)
		*(--ptr) = (value) | '0';

	return ptr;
}

char *
uint64_to_str_back(char *ptr, guint64 value)
{
	char const *p;

	/* special case */
	if (value == 0)
		*(--ptr) = '0';

	while (value >= 10) {
		p = fast_strings[100 + (value % 100)];

		value /= 100;

		*(--ptr) = p[2];
		*(--ptr) = p[1];
	}

	/* value will be 0..9, so using '& 0xF' is safe, and faster than '% 10' */
	if (value)
		*(--ptr) = (value & 0xF) | '0';

	return ptr;
}

char *
uint_to_str_back_len(char *ptr, guint32 value, int len)
{
	char *new_ptr;

	new_ptr = uint_to_str_back(ptr, value);

	/* substract from len number of generated characters */
	len -= (int)(ptr - new_ptr);

	/* pad remaining with '0' */
	while (len > 0)
	{
		*(--new_ptr) = '0';
		len--;
	}

	return new_ptr;
}

char *
uint64_to_str_back_len(char *ptr, guint64 value, int len)
{
	char *new_ptr;

	new_ptr = uint64_to_str_back(ptr, value);

	/* substract from len number of generated characters */
	len -= (int)(ptr - new_ptr);

	/* pad remaining with '0' */
	while (len > 0)
	{
		*(--new_ptr) = '0';
		len--;
	}

	return new_ptr;
}

char *
int_to_str_back(char *ptr, gint32 value)
{
	if (value < 0) {
		ptr = uint_to_str_back(ptr, -value);
		*(--ptr) = '-';
	} else
		ptr = uint_to_str_back(ptr, value);

	return ptr;
}

char *
int64_to_str_back(char *ptr, gint64 value)
{
	if (value < 0) {
		ptr = uint64_to_str_back(ptr, -value);
		*(--ptr) = '-';
	} else
		ptr = uint64_to_str_back(ptr, value);

	return ptr;
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */