From: Michael Gernoth <michael@gernoth.net>
Date: Thu, 30 May 2013 10:27:00 +0000 (+0200)
Subject: get rid of strtoul/printf for ascii-hex/bin conversion
X-Git-Tag: v0.100~97
X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/hmcfgusb/commitdiff_plain/51d4ece67f9843cef2eaebc84fb7e98716fe28ab

get rid of strtoul/printf for ascii-hex/bin conversion
---

diff --git a/hmland.c b/hmland.c
index 8e5a8e9..c8781a9 100644
--- a/hmland.c
+++ b/hmland.c
@@ -56,6 +56,8 @@ static int verbose = 0;
 
 static int format_part_out(uint8_t **inpos, int inlen, uint8_t **outpos, int outlen, int len, int flags)
 {
+	const uint8_t nibble[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+		'A', 'B', 'C', 'D', 'E', 'F'};
 	uint8_t *buf_out = *outpos;
 	uint8_t *outend = *outpos + outlen;
 	uint8_t *inend = *inpos + inlen;
@@ -74,20 +76,13 @@ static int format_part_out(uint8_t **inpos, int inlen, uint8_t **outpos, int out
 	}
 
 	if (flags & FLAG_FORMAT_HEX) {
-		char hex[3];
-
-		memset(hex, 0, sizeof(hex));
-
 		CHECK_AVAIL(len);
 		CHECK_SPACE(len*2);
 		for (i = 0; i < len; i++) {
-			if (snprintf(hex, sizeof(hex), "%02X", **inpos) != 2) {
-				fprintf(stderr, "Can't format hex-string!\n");
-				return 0;
-			}
-			*inpos += 1;
-			memcpy(*outpos, hex, 2);
-			*outpos += 2;
+			**outpos = nibble[((**inpos) & 0xf0) >> 4];
+			*outpos += 1;
+			**outpos = nibble[((**inpos) & 0xf)];
+			*inpos += 1; *outpos += 1;
 		}
 	} else {
 		CHECK_AVAIL(len);
@@ -114,14 +109,26 @@ static int format_part_out(uint8_t **inpos, int inlen, uint8_t **outpos, int out
 	return *outpos - buf_out;
 }
 
+static uint8_t ascii_to_nibble(uint8_t a)
+{
+	uint8_t c = 0x00;
+
+	if ((a >= '0') && (a <= '9')) {
+		c = a - '0';
+	} else if ((a >= 'A') && (a <= 'F')) {
+		c = (a - 'A') + 10;
+	} else if ((a >= 'a') && (a <= 'f')) {
+		c = (a - 'a') + 10;
+	}
+
+	return c;
+}
+
 static int parse_part_in(uint8_t **inpos, int inlen, uint8_t **outpos, int outlen, int flags)
 {
 	uint8_t *buf_out = *outpos;
 	uint8_t *outend = *outpos + outlen;
 	uint8_t *inend = *inpos + inlen;
-	char hex[3];
-
-	memset(hex, 0, sizeof(hex));
 
 	if (flags & FLAG_LENGTH_BYTE) {
 		int len = 0;
@@ -155,11 +162,11 @@ static int parse_part_in(uint8_t **inpos, int inlen, uint8_t **outpos, int outle
 
 		CHECK_SPACE(1);
 		CHECK_AVAIL(2);
-		memcpy(hex, *inpos, 2);
-		*inpos += 2;
 
-		**outpos = strtoul(hex, NULL, 16);
-		*outpos += 1;
+		**outpos = ascii_to_nibble(**inpos) << 4;
+		*inpos += 1;
+		**outpos |= ascii_to_nibble(**inpos);
+		*inpos += 1; *outpos += 1;
 	}
 
 	return *outpos - buf_out;