PacketCrypt/src/ContentMerkle.c at develop · javascriptit/PacketCrypt · GitHub

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/**

* Caleb James DeLisle

* SPDX-License-Identifier: (LGPL-2.1-only OR LGPL-3.0-only)

#include "ContentMerkle.h"

#include "Hash.h"

#include "Util.h"

#include "Buf.h"

static void computeCycle(Buf32_t* outBuf, uint8_t* buf, int realLength, int chunkLength) {

if (realLength <= 32 || chunkLength == 32) {

Buf_OBJSET(outBuf, 0);

memcpy(outBuf->bytes, buf, realLength);

return;

}

int halfLen = chunkLength >> 1;

if (halfLen >= realLength) {

computeCycle(outBuf, buf, realLength, halfLen);

return;

}

Buf64_t b = {{0}};

computeCycle(&b.thirtytwos[0], buf, halfLen, halfLen),

computeCycle(&b.thirtytwos[1], &buf[halfLen], realLength - halfLen, halfLen);

Hash_COMPRESS32_OBJ(outBuf, &b);

}

void ContentMerkle_compute(Buf32_t* outBuf, uint8_t* buf, uint32_t length)

{

computeCycle(outBuf, buf, length, 1 << Util_log2ceil(length));

}

const uint8_t* ContentMerkle_getProofBlock(

uint32_t proofIdx,

Buf32_t* buf,

const uint8_t* content,

uint32_t contentLen

) {

if (contentLen <= 32) { return NULL; }

assert(content);

uint32_t totalBlocks = contentLen / 32;

if (totalBlocks*32 < contentLen) { totalBlocks++; }

uint32_t idx = (proofIdx % totalBlocks) * 32;

if ((idx + 32) > contentLen) {

int len = contentLen - idx;

Buf_OBJSET(buf, 0);

memcpy(buf->bytes, &content[idx], len);

return buf->bytes;

} else {

return &content[idx];

}

PacketCrypt/src/ContentMerkle.c at develop · javascriptit/PacketCrypt · GitHub

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