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#ifndef SRL_READER_MISC_H_
#define SRL_READER_MISC_H_
#include "srl_inline.h"
#include "srl_common.h"
#include "srl_reader.h"
#include "srl_protocol.h"
/* not sure that this's the best location for this function */
SRL_STATIC_INLINE IV
srl_validate_header_version(pTHX_ srl_reader_char_ptr strdata, STRLEN len)
{
if ( len >= SRL_MAGIC_STRLEN + 3 ) {
/* + 3 above because:
* at least one version/flag byte,
* one byte for header len,
* one type byte (smallest payload)
*/
/* Do NOT do *((U32*)strdata at least for these reasons:
* (1) Unaligned access can "Bus error" on you
* (char* can be much less aligned than U32).
* (2) In ILP64 even if aligned the U32 would be 64 bits wide,
* and the deref would read 8 bytes, more than the smallest
* (valid) message.
* (3) Endianness.
*/
U8 version_encoding= strdata[SRL_MAGIC_STRLEN];
U8 version= version_encoding & SRL_PROTOCOL_VERSION_MASK;
if ( memEQ(SRL_MAGIC_STRING, strdata, SRL_MAGIC_STRLEN) ) {
if ( 0 < version && version < 3 ) {
return version_encoding;
}
}
else
if ( memEQ(SRL_MAGIC_STRING_HIGHBIT, strdata, SRL_MAGIC_STRLEN) ) {
if ( 3 <= version ) {
return version_encoding;
}
}
else
if ( memEQ(SRL_MAGIC_STRING_HIGHBIT_UTF8, strdata, SRL_MAGIC_STRLEN) ) {
return 0;
}
}
return -1;
}
#endif
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