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ootp/common/str.c

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/*
* Copyright (c) 2005 Mark Fullmer
* Copyright (c) 2009 Mark Fullmer and the Ohio State University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $Id: str.c 15 2009-11-26 18:29:41Z maf $
*/
#include <termios.h>
#if HAVE_STRINGS_H
#include <strings.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "str.h"
/*
* function: chr_hex_l()
*
* convert ASCII hex left digit to binary
*
* arguments:
* h - 8 bit value to convert
*
* example, i = 15:
* i = chr_hex_r(0xF0)
*
* returns binary representation of left ASCII hex character h
*
*/
char chr_hex_l(u_char h)
{
u_char t;
t = ((h&0xF0)>>4);
if (t > 9)
return (t-10) + 'A';
return t + '0';
} /* chr_hex_l */
/*
* function: chr_hex_r()
*
* convert ASCII hex right digit to binary
*
* example, i = 0:
* i = chr_hex_r(0xF0)
*
* arguments:
* h - 8 bit value to convert
*
* returns binary representation of right ASCII hex character h
*
*/
char chr_hex_r(u_char h)
{
u_char t;
t = (h&0x0F);
if (t > 9)
return (t-10) + 'A';
return t + '0';
} /* chr_hex_r */
/*
* function: chr_hex_decode()
*
* convert 4 bit ASCII hex to binary
*
* example, i = 15
* i = chr_hex_decode('F');
*
* returns binary representation of ASCII hex character h (0..15)
* or 0xFF on error
*
*/
u_char chr_hex_decode(char h)
{
if ((h >= '0') && (h <= '9'))
return h - '0';
if ((h >= 'A') && (h <= 'F'))
return h - 'A' + 10;
if ((h >= 'a') && (h <= 'f'))
return h - 'a' + 10;
/* fatal */
return 0xFF;
} /* chr_hex_decode */
/*
* function: chr_ishex()
*
* example, i = 0
* i = ishex('F')
* example, i = -1
* i = ishex('g')
*
* returns:
* 0 d is ASCII hex character
* -1 d is not ASCII hex character
*
*/
int chr_ishex(char d)
{
if ((d >= '0') && (d <= '9'))
return 0;
if ((d >= 'A') && (d <= 'F'))
return 0;
if ((d >= 'a') && (d <= 'f'))
return 0;
return -1;
} /* chr_ishex */
/*
* function: str_hex_dump()
*
* dumps n bytes of b into buf as hex digits
* caller is responsible for allocating buf
* each input byte translates to two bytes in output buffer + 1 null terminator
*
* arguments:
* buf - output buffer (allocated by caller)
* b - bit stream to decode
* n - length of b in bytes
*
*/
void str_hex_dump(char *buf, u_char *b, size_t n)
{
int i, j;
for (i = 0, j = 0; i < n; ++i) {
buf[j++] = chr_hex_l(*b);
buf[j++] = chr_hex_r(*b++);
}
buf[j] = 0;
}
/*
* function: str_hex_decode()
*
* decode max of in_len bytes from in as hex, store result in out.
* out is out_len bytes
*
* arguments:
* in - null terminated character string to decode.
* in_len - max hex digits to decode (may be > strlen(in)
* out - decoded bits
* out_len - length of out buffer
*
* returns: <0 error (non hex digit encountered)
* 0 successful decode
*
*/
int str_hex_decode(char *in, size_t in_len, u_char *out, size_t out_len)
{
int i, l;
unsigned char v, odd;
bzero(out, out_len);
l = strlen(in);
odd = 0;
out += out_len-1;
if (l > in_len)
return -1;
in += l-1;
for (i = 0; i < l; ++i) {
if (*in >= '0' && *in <= '9')
v = *in - '0';
else if (*in >= 'a' && *in <= 'f')
v = *in - 'a' + 10;
else if (*in >= 'A' && *in <= 'F')
v = *in - 'A' + 10;
else return -1;
if (!odd) {
*out |= v;
} else {
*out |= v<<4;
--out;
}
--in;
odd = odd ? 0 : 1;
}
return 0;
} /* str_hex_decode */
/*
* function: str_ftoc()
*
* convert fixed length string to null terminated C string.
* a fixed length string may not have terminating null if it
* is the max length
*
* arguments:
* buf - null terminated output buffer (allocated by caller, min n+1 bytes)
* f - fixed length string
* n - max length of f in bytes
*
*/
void str_ftoc(char *buf, char *f, size_t n)
{
int i;
for (i = 0; i < n; ++i)
if (!(buf[i] = f[i]))
break;
buf[i] = 0;
} /* str_ftoc */
/*
* function: str_input()
*
* input a string of maximum length buf_size-1 characters from stdin,
* null terminate unless input has overflowed.
*
*
* arguments:
* prompt - user prompt
* buf - input buffer (allocated by caller)
* buf_size - size in bytes of input buffer
* flags - STR_FLAGS_*
* STR_ECHO_OFF - disable echo
*
* returns: < 0 fatal error
* 0 success
* -2 not all input read, buffer too short
*
*/
int str_input(const char *prompt, char *buf, size_t buf_size, int flags)
{
struct termios t;
int i, r, ret;
char c;
ret = -1; /* fail */
/* sanity check */
if (buf_size <= 1)
return -1;
/* change tty mode? */
if (flags & STR_FLAGS_ECHO_OFF) {
if (tcgetattr(STDIN_FILENO, &t) < 0)
return -1;
t.c_lflag &= ~ECHO;
}
printf("%s", prompt); fflush(stdout);
i = 0;
while (1) {
/* get 1 char */
if ((r = read(STDIN_FILENO, &c, 1)) < 0)
goto str_input_out;
/* EOF? */
if (r == 0) {
buf[i] = 0;
break;
}
/* \n */
if (c == '\n') {
buf[i] = 0;
break;
}
/* copy input to buf, check overflow */
if ((i+1) == buf_size) {
ret = -2;
buf[i] = 0;
goto str_input_out;
} else {
buf[i++] = c;
}
} /* forever */
ret = 0; /* success */
str_input_out:
/* restore tty? */
if (flags & STR_FLAGS_ECHO_OFF) {
if (tcgetattr(STDIN_FILENO, &t) < 0)
return -1;
t.c_lflag |= ECHO;
}
return ret;
} /* str_input */
/*
* function: str_safe
*
* Ensure length of string is not > len
* note n is the length of the string
* where n+1 bytes are required to store
* it with trailing null.
*
* Ensure string is limited to [a-zA-Z0-9.]
*
* First invalid character is set to 0.
*
* returns "safe" string
*
*/
int str_safe(char *input, size_t len)
{
size_t n;
int ret;
ret = 0; /* success */
n = strlen(input);
/* bounds verification */
if (n > len) {
input[len] = 0;
ret = -1;
}
for (n = 0; n < len; ++n) {
/* a-z */
if ((input[n] >= 'a') && (input[n] <= 'z'))
continue;
/* A-Z */
if ((input[n] >= 'A') && (input[n] <= 'Z'))
continue;
/* 0-9 */
if ((input[n] >= '0') && (input[n] <= '9'))
continue;
/* . */
if (input[n] == '.')
continue;
/* unsafe */
input[n] = 0;
ret = -1;
break;
} /* for each byte in input */
return ret;
} /* str_safe */
#ifdef STR_EXAMPLE
#include <stdio.h>
#include "str.h"
main()
{
char buf[1024];
unsigned char b[4];
int i;
i = str_input("prompt: ", buf, 2, STR_FLAGS_ECHO_OFF);
printf("i=%d\n", i);
printf("buf=%s\n", buf);
b[0] = 0x1A;
b[1] = 0x2B;
b[2] = 0x3C;
b[3] = 0x4D;
str_hex_dump(buf, b, 4);
printf("%s\n", buf);
b[0] = 'A';
b[1] = 'B';
b[2] = 0;
str_ftoc(buf, b, 4);
printf("%s\n", buf);
b[0] = 'A';
b[1] = 'B';
b[2] = 'C';
b[3] = 'D';
str_ftoc(buf, b, 4);
printf("%s\n", buf);
}
#endif /* STR_EXAMPLE */
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