static void
build_prepend_package_length(GArray *package, unsigned length, bool incl_self)
{
uint8_t byte;
unsigned length_bytes;
if (length + 1 < (1 << PACKAGE_LENGTH_1BYTE_SHIFT)) {
length_bytes = 1;
} else if (length + 2 < (1 << PACKAGE_LENGTH_3BYTE_SHIFT)) {
length_bytes = 2;
} else if (length + 3 < (1 << PACKAGE_LENGTH_4BYTE_SHIFT)) {
length_bytes = 3;
} else {
length_bytes = 4;
}
/*
* NamedField uses PkgLength encoding but it doesn't include length
* of PkgLength itself.
*/
if (incl_self) {
/*
* PkgLength is the length of the inclusive length of the data
* and PkgLength's length itself when used for terms with
* explitit length.
*/
length += length_bytes;
}
switch (length_bytes) {
case 1:
byte = length;
build_prepend_byte(package, byte);
return;
case 4:
byte = length >> PACKAGE_LENGTH_4BYTE_SHIFT;
build_prepend_byte(package, byte);
length &= (1 << PACKAGE_LENGTH_4BYTE_SHIFT) - 1;
/* fall through */
case 3:
byte = length >> PACKAGE_LENGTH_3BYTE_SHIFT;
build_prepend_byte(package, byte);
length &= (1 << PACKAGE_LENGTH_3BYTE_SHIFT) - 1;
/* fall through */
case 2:
byte = length >> PACKAGE_LENGTH_2BYTE_SHIFT;
build_prepend_byte(package, byte);
length &= (1 << PACKAGE_LENGTH_2BYTE_SHIFT) - 1;
/* fall through */
}
/*
* Most significant two bits of byte zero indicate how many following bytes
* are in PkgLength encoding.
*/
byte = ((length_bytes - 1) << PACKAGE_LENGTH_1BYTE_SHIFT) | length;
build_prepend_byte(package, byte);
}
static void build_prepend_package_length(GArray *package, unsigned min_bytes)
{
uint8_t byte;
unsigned length = package->len;
unsigned length_bytes;
if (length + 1 < (1 << PACKAGE_LENGTH_1BYTE_SHIFT)) {
length_bytes = 1;
} else if (length + 2 < (1 << PACKAGE_LENGTH_3BYTE_SHIFT)) {
length_bytes = 2;
} else if (length + 3 < (1 << PACKAGE_LENGTH_4BYTE_SHIFT)) {
length_bytes = 3;
} else {
length_bytes = 4;
}
/* Force length to at least min_bytes.
* This wastes memory but that's how bios did it.
*/
length_bytes = MAX(length_bytes, min_bytes);
/* PkgLength is the length of the inclusive length of the data. */
length += length_bytes;
switch (length_bytes) {
case 1:
byte = length;
build_prepend_byte(package, byte);
return;
case 4:
byte = length >> PACKAGE_LENGTH_4BYTE_SHIFT;
build_prepend_byte(package, byte);
length &= (1 << PACKAGE_LENGTH_4BYTE_SHIFT) - 1;
/* fall through */
case 3:
byte = length >> PACKAGE_LENGTH_3BYTE_SHIFT;
build_prepend_byte(package, byte);
length &= (1 << PACKAGE_LENGTH_3BYTE_SHIFT) - 1;
/* fall through */
case 2:
byte = length >> PACKAGE_LENGTH_2BYTE_SHIFT;
build_prepend_byte(package, byte);
length &= (1 << PACKAGE_LENGTH_2BYTE_SHIFT) - 1;
/* fall through */
}
/*
* Most significant two bits of byte zero indicate how many following bytes
* are in PkgLength encoding.
*/
byte = ((length_bytes - 1) << PACKAGE_LENGTH_1BYTE_SHIFT) | length;
build_prepend_byte(package, byte);
}
static void build_extop_package(GArray *package, uint8_t op)
{
build_package(package, op);
build_prepend_byte(package, 0x5B); /* ExtOpPrefix */
}
static void build_package(GArray *package, uint8_t op)
{
build_prepend_package_length(package, package->len, true);
build_prepend_byte(package, op);
}
static void build_package(GArray *package, uint8_t op, unsigned min_bytes)
{
build_prepend_package_length(package, min_bytes);
build_prepend_byte(package, op);
}