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copied!<p>The following functions pack/unpack bytes representing a single precision floating point value to/from a buffer in network byte order. Only the pack method needs to take endianness into account since the unpack method explicitly constructs the 32-bit value from the individual bytes by bit shifting them the appropriate amount and then OR-ing them together. These functions are only valid for C/C++ implementations that store a float in 32-bits. This is true for <a href="http://en.wikipedia.org/wiki/IEEE_754-1985" rel="nofollow noreferrer">IEEE 754-1985</a> floating point implementations.</p> <pre><code>// unpack method for retrieving data in network byte, // big endian, order (MSB first) // increments index i by the number of bytes unpacked // usage: // int i = 0; // float x = unpackFloat(&buffer[i], &i); // float y = unpackFloat(&buffer[i], &i); // float z = unpackFloat(&buffer[i], &i); float unpackFloat(const void *buf, int *i) { const unsigned char *b = (const unsigned char *)buf; uint32_t temp = 0; *i += 4; temp = ((b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3]); return *((float *) &temp); } // pack method for storing data in network, // big endian, byte order (MSB first) // returns number of bytes packed // usage: // float x, y, z; // int i = 0; // i += packFloat(&buffer[i], x); // i += packFloat(&buffer[i], y); // i += packFloat(&buffer[i], z); int packFloat(void *buf, float x) { unsigned char *b = (unsigned char *)buf; unsigned char *p = (unsigned char *) &x; #if defined (_M_IX86) || (defined (CPU_FAMILY) && (CPU_FAMILY == I80X86)) b[0] = p[3]; b[1] = p[2]; b[2] = p[1]; b[3] = p[0]; #else b[0] = p[0]; b[1] = p[1]; b[2] = p[2]; b[3] = p[3]; #endif return 4; } </code></pre>

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