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split rlp_encode_length into rlp_encode_length and rlp_encode_list_length

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This commit is contained in:
Pavol Rusnak 2016-08-16 14:06:05 +02:00 committed by Alex Beregszaszi
parent 3db323c599
commit 1558d77ea0
1 changed files with 39 additions and 11 deletions
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50
firmware/ethereum.c
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@ -38,28 +38,56 @@ struct SHA3_CTX keccak_ctx;
/*
* Encode length according to RLP.
* FIXME: improve
*/
static int rlp_encode_length(uint8_t *buf, int length, uint8_t firstbyte, bool list)
static int rlp_encode_length(uint8_t *buf, int length, uint8_t firstbyte)
{
if (!list && (length == 1 && firstbyte <= 0x7f)) {
/* Extra-special case: null is encoded differently */
buf[0] = !firstbyte ? 0x80 : firstbyte;
if (length == 1 && firstbyte == 0x00) {
// extra-special case: null is encoded differently
buf[0] = 0x80;
return 1;
} else if (length == 1 && firstbyte <= 0x7f) {
buf[0] = firstbyte;
return 1;
} else if (length <= 55) {
buf[0] = (list ? 0xc0 : 0x80) + length;
buf[0] = 0x80 + length;
return 1;
} else if (length <= 0xff) {
buf[0] = (list ? 0xf7 : 0xb7) + 1;
buf[0] = 0xb7 + 1;
buf[1] = length;
return 2;
} else if (length <= 0xffff) {
buf[0] = (list ? 0xf7 : 0xb7) + 2;
buf[0] = 0xb7 + 2;
buf[1] = length >> 8;
buf[2] = length & 0xff;
return 3;
} else {
buf[0] = (list ? 0xf7 : 0xb7) + 3;
buf[0] = 0xb7 + 3;
buf[1] = length >> 16;
buf[2] = length >> 8;
buf[3] = length & 0xff;
return 4;
}
}
/*
* Encode list length according to RLP.
*/
static int rlp_encode_list_length(uint8_t *buf, int length)
{
if (length <= 55) {
buf[0] = 0xc0 + length;
return 1;
} else if (length <= 0xff) {
buf[0] = 0xf7 + 1;
buf[1] = length;
return 2;
} else if (length <= 0xffff) {
buf[0] = 0xf7 + 2;
buf[1] = length >> 8;
buf[2] = length & 0xff;
return 3;
} else {
buf[0] = 0xf7 + 3;
buf[1] = length >> 16;
buf[2] = length >> 8;
buf[3] = length & 0xff;
@ -97,7 +125,7 @@ static inline void hash_data(const uint8_t *buf, size_t size)
static void hash_rlp_length(int length, uint8_t firstbyte)
{
uint8_t buf[4];
size_t size = rlp_encode_length(buf, length, firstbyte, false);
size_t size = rlp_encode_length(buf, length, firstbyte);
hash_data(buf, size);
}
@ -107,7 +135,7 @@ static void hash_rlp_length(int length, uint8_t firstbyte)
static void hash_rlp_list_length(int length)
{
uint8_t buf[4];
size_t size = rlp_encode_length(buf, length, 0, true);
size_t size = rlp_encode_list_length(buf, length);
hash_data(buf, size);
}