FlapJackApps/libdivecomputer
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Do not attempt to read data if it's not required.

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This commit is contained in:
Jef Driesen 2007-11-17 09:40:24 +00:00
parent 5e9279b99d
commit b847086ad7
1 changed files with 21 additions and 15 deletions
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36
suunto_vyper.c
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@ -248,6 +248,9 @@ suunto_vyper_transfer (vyper *device, const unsigned char command[], unsigned in
return rc; return rc;
} }
// Initial checksum value.
unsigned char ccrc = 0x00;
// FIXME: Give the DC extra answer time to send its first byte, // FIXME: Give the DC extra answer time to send its first byte,
// then let the standard timeout apply. // then let the standard timeout apply.
@ -260,18 +263,19 @@ suunto_vyper_transfer (vyper *device, const unsigned char command[], unsigned in
} }
return EXITCODE (rc, hsize); return EXITCODE (rc, hsize);
} }
// Update the checksum.
// Receive the contents of the package.
rc = serial_read (device->port, data, size);
if (rc != size) {
WARNING ("Unexpected EOF in answer.");
return EXITCODE (rc, size);
}
// Calculate the checksum.
unsigned char ccrc = 0x00;
ccrc = suunto_vyper_checksum (header, hsize, ccrc); ccrc = suunto_vyper_checksum (header, hsize, ccrc);
ccrc = suunto_vyper_checksum (data, size, ccrc);
if (data) {
// Receive the contents of the package.
rc = serial_read (device->port, data, size);
if (rc != size) {
WARNING ("Unexpected EOF in answer.");
return EXITCODE (rc, size);
}
// Update the checksum.
ccrc = suunto_vyper_checksum (data, size, ccrc);
}
// Receive (and verify) the checksum of the package. // Receive (and verify) the checksum of the package.
unsigned char crc = 0x00; unsigned char crc = 0x00;
@ -409,6 +413,9 @@ suunto_vyper_read_dive (vyper *device, unsigned char data[], unsigned int size,
unsigned int nbytes = 0; unsigned int nbytes = 0;
for (;;) { for (;;) {
// Initial checksum value.
unsigned char ccrc = 0x00;
// Receive the header of the package. // Receive the header of the package.
unsigned char header[2] = {0}; unsigned char header[2] = {0};
rc = serial_read (device->port, header, 2); rc = serial_read (device->port, header, 2);
@ -428,6 +435,8 @@ suunto_vyper_read_dive (vyper *device, unsigned char data[], unsigned int size,
WARNING ("Unexpected answer start byte(s)."); WARNING ("Unexpected answer start byte(s).");
return EXITCODE (rc, 2); return EXITCODE (rc, 2);
} }
// Update the checksum.
ccrc = suunto_vyper_checksum (header, 2, ccrc);
// Receive the contents of the package. // Receive the contents of the package.
unsigned char len = header[1]; unsigned char len = header[1];
@ -437,10 +446,7 @@ suunto_vyper_read_dive (vyper *device, unsigned char data[], unsigned int size,
WARNING ("Unexpected EOF in answer."); WARNING ("Unexpected EOF in answer.");
return EXITCODE (rc, len); return EXITCODE (rc, len);
} }
// Update the checksum.
// Calculate the checksum.
unsigned char ccrc = 0x00;
ccrc = suunto_vyper_checksum (header, 2, ccrc);
ccrc = suunto_vyper_checksum (package, len, ccrc); ccrc = suunto_vyper_checksum (package, len, ccrc);
// Receive (and verify) the checksum of the package. // Receive (and verify) the checksum of the package.