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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. * 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)) { if (length == 1 && firstbyte == 0x00) {
/* Extra-special case: null is encoded differently */ // extra-special case: null is encoded differently
buf[0] = !firstbyte ? 0x80 : firstbyte; buf[0] = 0x80;
return 1;
} else if (length == 1 && firstbyte <= 0x7f) {
buf[0] = firstbyte;
return 1; return 1;
} else if (length <= 55) { } else if (length <= 55) {
buf[0] = (list ? 0xc0 : 0x80) + length; buf[0] = 0x80 + length;
return 1; return 1;
} else if (length <= 0xff) { } else if (length <= 0xff) {
buf[0] = (list ? 0xf7 : 0xb7) + 1; buf[0] = 0xb7 + 1;
buf[1] = length; buf[1] = length;
return 2; return 2;
} else if (length <= 0xffff) { } else if (length <= 0xffff) {
buf[0] = (list ? 0xf7 : 0xb7) + 2; buf[0] = 0xb7 + 2;
buf[1] = length >> 8; buf[1] = length >> 8;
buf[2] = length & 0xff; buf[2] = length & 0xff;
return 3; return 3;
} else { } 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[1] = length >> 16;
buf[2] = length >> 8; buf[2] = length >> 8;
buf[3] = length & 0xff; 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) static void hash_rlp_length(int length, uint8_t firstbyte)
{ {
uint8_t buf[4]; 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); 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) static void hash_rlp_list_length(int length)
{ {
uint8_t buf[4]; 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); hash_data(buf, size);
} }