hexUtils.c

/*
*******************************************************************************    
*   BTChip Bitcoin Hardware Wallet C test interface
*   (c) 2014 BTChip - 1BTChip7VfTnrPra5jqci7ejnMguuHogTn
*   
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
*   Unless required by applicable law or agreed to in writing, software
*   distributed under the License is distributed on an "AS IS" BASIS,
*   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*   limitations under the License.
********************************************************************************/

#include "hexUtils.h"

int getNibble(char x) {
	if ((x >= '0') && (x <= '9')) {
		return (x - '0');
	}
	if ((x >= 'A') && (x <= 'F')) {
		return ((x - 'A') + 10);
	}
	if ((x >= 'a') && (x <= 'f')) {
		return ((x - 'a') + 10);
	}
	return -1;
}

size_t hexToBin(const char *data, unsigned char *out, size_t outLength) {
	int i;
	int length = strlen(data);
	if ((length % 2) != 0) {
		return 0;
	}
	if (outLength < (length / 2)) {
		return 0;
	}
	for (i=0; i<length; i+=2) {
		int nibbleHigh = getNibble(data[i]);
		int nibbleLow = getNibble(data[i + 1]);	
		if ((nibbleHigh < 0) || (nibbleLow < 0)) {
			return 0;
		}
		out[i / 2] = ((nibbleHigh << 4) | nibbleLow);
	}
	return (length / 2);
} 

void displayBinary(unsigned char *buffer, size_t length) {
	size_t i;
	for (i=0; i<length; i++) {
		printf("%.2x", buffer[i]);
	}
	printf("\n");
}