/*-------------------------------------------------------------------------
 * drawElements Base Portability Library
 * -------------------------------------
 *
 * Copyright 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *//*!
 * \file
 * \brief SHA1 hash functions.
 *//*--------------------------------------------------------------------*/

#include "deSha1.h"

#include "deMemory.h"

DE_BEGIN_EXTERN_C

enum
{
    CHUNK_BIT_SIZE  = 512,
    CHUNK_BYTE_SIZE = CHUNK_BIT_SIZE / 8
};

static uint32_t leftRotate(uint32_t val, uint32_t count)
{
    DE_ASSERT(count < 32);

    return (val << count) | (val >> (32 - count));
}

void deSha1Stream_init(deSha1Stream *stream)
{
    stream->size = 0;

    /* Set the initial 16 deUint32s that contain real data to zeros. */
    deMemset(stream->data, 0, 16 * sizeof(uint32_t));

    stream->hash[0] = 0x67452301u;
    stream->hash[1] = 0xEFCDAB89u;
    stream->hash[2] = 0x98BADCFEu;
    stream->hash[3] = 0x10325476u;
    stream->hash[4] = 0xC3D2E1F0u;
}

static void deSha1Stream_flushChunk(deSha1Stream *stream)
{
    DE_ASSERT(stream->size % CHUNK_BYTE_SIZE == 0 && stream->size > 0);

    {
        size_t ndx;

        /* Expand the 16 uint32s that contain the data to 80. */
        for (ndx = 16; ndx < DE_LENGTH_OF_ARRAY(stream->data); ndx++)
        {
            stream->data[ndx] = leftRotate(
                stream->data[ndx - 3] ^ stream->data[ndx - 8] ^ stream->data[ndx - 14] ^ stream->data[ndx - 16], 1);
        }
    }

    {
        uint32_t a = stream->hash[0];
        uint32_t b = stream->hash[1];
        uint32_t c = stream->hash[2];
        uint32_t d = stream->hash[3];
        uint32_t e = stream->hash[4];
        size_t ndx;

        for (ndx = 0; ndx < DE_LENGTH_OF_ARRAY(stream->data); ndx++)
        {
            uint32_t f;
            uint32_t k;

            if (ndx < 20)
            {
                f = (b & c) | ((~b) & d);
                k = 0x5A827999u;
            }
            else if (ndx < 40)
            {
                f = b ^ c ^ d;
                k = 0x6ED9EBA1u;
            }
            else if (ndx < 60)
            {
                f = (b & c) | (b & d) | (c & d);
                k = 0x8F1BBCDCu;
            }
            else
            {
                f = b ^ c ^ d;
                k = 0xCA62C1D6u;
            }

            {
                const uint32_t tmp = leftRotate(a, 5) + f + e + k + stream->data[ndx];

                e = d;
                d = c;
                c = leftRotate(b, 30);
                b = a;
                a = tmp;
            }
        }

        stream->hash[0] += a;
        stream->hash[1] += b;
        stream->hash[2] += c;
        stream->hash[3] += d;
        stream->hash[4] += e;

        /* Set the initial 16 deUint32s that contain the real data to zeros. */
        deMemset(stream->data, 0, 16 * sizeof(uint32_t));
    }
}

void deSha1Stream_process(deSha1Stream *stream, size_t size, const void *data_)
{
    const uint8_t *const data = (const uint8_t *)data_;
    size_t bytesProcessed     = 0;

    while (bytesProcessed < size)
    {
        do
        {
            const size_t bitOffset = (size_t)(8 * (4 - (1 + (stream->size % 4))));

            stream->data[(stream->size / 4) % 16] |= ((uint32_t)data[bytesProcessed]) << (uint32_t)bitOffset;

            stream->size++;
            bytesProcessed++;
        } while (stream->size % CHUNK_BYTE_SIZE != 0 && bytesProcessed < size);

        if (stream->size % CHUNK_BYTE_SIZE == 0)
            deSha1Stream_flushChunk(stream);
    }

    DE_ASSERT(bytesProcessed == size);
}

void deSha1Stream_finalize(deSha1Stream *stream, deSha1 *hash)
{
    /* \note First element is initialized to 0x80u and rest to 0x0. */
    static const uint8_t padding[CHUNK_BYTE_SIZE] = {0x80u};
    const uint64_t length                         = stream->size * 8;
    uint8_t lengthData[sizeof(uint64_t)];
    size_t ndx;

    DE_ASSERT(padding[0] == 0x80u);
    DE_ASSERT(padding[1] == 0x0u);

    for (ndx = 0; ndx < sizeof(uint64_t); ndx++)
        lengthData[ndx] = (uint8_t)(0xffu & (length >> (8 * (sizeof(uint64_t) - 1 - ndx))));

    {
        const uint64_t spaceLeftInChunk = CHUNK_BYTE_SIZE - (stream->size % CHUNK_BYTE_SIZE);

        /* The stream must be a multiple of 512 bits (CHUNK_BYTE_SIZE) and is terminated by a single bit set to 1,
         * then 7 or more 0 bits, then finally the last 64 bits are the message length. */

        if (spaceLeftInChunk >= 1 + sizeof(lengthData))
        {
            /* There's room for a 0x80 byte and zero or more 0x0 padding bytes. */
            deSha1Stream_process(stream, (size_t)(spaceLeftInChunk - sizeof(lengthData)), padding);
        }
        else
        {
            /* 0x80 and the message length won't fit in this chunk, we need to add a whole new chunk of zero padding,
             * which will include the message length at the end. */
            deSha1Stream_process(stream, (size_t)(spaceLeftInChunk), padding);
            deSha1Stream_process(stream, (size_t)(CHUNK_BYTE_SIZE - sizeof(lengthData)), padding + spaceLeftInChunk);
        }
    }

    deSha1Stream_process(stream, sizeof(lengthData), lengthData);
    DE_ASSERT(stream->size % CHUNK_BYTE_SIZE == 0);

    deMemcpy(hash->hash, stream->hash, sizeof(hash->hash));
}

void deSha1_compute(deSha1 *hash, size_t size, const void *data)
{
    deSha1Stream stream;

    deSha1Stream_init(&stream);
    deSha1Stream_process(&stream, size, data);
    deSha1Stream_finalize(&stream, hash);
}

void deSha1_render(const deSha1 *hash, char *buffer)
{
    size_t charNdx;

    for (charNdx = 0; charNdx < 40; charNdx++)
    {
        const uint32_t val32 = hash->hash[charNdx / 8];
        const uint8_t val8   = (uint8_t)(0x0fu & (val32 >> (4 * (8 - 1 - (charNdx % 8)))));

        if (val8 < 10)
            buffer[charNdx] = (char)('0' + val8);
        else
            buffer[charNdx] = (char)('a' + val8 - 10);
    }
}

bool deSha1_parse(deSha1 *hash, const char *buffer)
{
    size_t charNdx;

    deMemset(hash->hash, 0, sizeof(hash->hash));

    for (charNdx = 0; charNdx < 40; charNdx++)
    {
        uint8_t val4;

        if (buffer[charNdx] >= '0' && buffer[charNdx] <= '9')
            val4 = (uint8_t)(buffer[charNdx] - '0');
        else if (buffer[charNdx] >= 'a' && buffer[charNdx] <= 'f')
            val4 = (uint8_t)(10 + (buffer[charNdx] - 'a'));
        else if (buffer[charNdx] >= 'A' && buffer[charNdx] <= 'F')
            val4 = (uint8_t)(10 + (buffer[charNdx] - 'A'));
        else
            return false;

        hash->hash[charNdx / 8] |= ((uint32_t)val4) << (4 * (8u - 1u - (charNdx % 8u)));
    }

    return true;
}

bool deSha1_equal(const deSha1 *a, const deSha1 *b)
{
    /* \note deMemcmp() can only be used for equality. It doesn't provide correct ordering between hashes. */
    return deMemCmp(a->hash, b->hash, sizeof(b->hash)) == 0;
}

void deSha1_selfTest(void)
{
    const char *const validHashStrings[] = {"ac890cfca05717c05dc831996b2289251da2984e",
                                            "0f87ba807acb3e6effe617249f30453a524a2ea3",
                                            "6f483cc3fa820e58ed9f83c83bdf8d213293b3ad"};

    const char *const invalidHashStrings[] = {
        " c890cfca05717c05dc831996b2289251da2984e",  "0f87ba807acb3e6 ffe617249f30453a524a2ea3",
        "6f483cc3fa820e58ed9f83c83bdf8d213293b3a ",

        "mc890cfca05717c05dc831996b2289251da2984e",  "0f87ba807acb3e6effe617249fm0453a524a2ea3",
        "6f483cc3fa820e58ed9f83c83bdf8d213293b3an",

        "ac890cfca05717c05dc83\n996b2289251da2984e", "0f87ba807acb3e6effe617\t49f30453a524a2ea3",
        "ac890cfca05717c05dc831\096b2289251da2984e", "6f483cc3fa{20e58ed9f83c83bdf8d213293b3ad"};

    const struct
    {
        const char *const hash;
        const char *const data;
    } stringHashPairs[] = {
        /* Generated using sha1sum. */
        {"da39a3ee5e6b4b0d3255bfef95601890afd80709", ""},
        {"aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d", "hello"},
        {"ec1919e856540f42bd0e6f6c1ffe2fbd73419975",
         "Cherry is a browser-based GUI for controlling deqp test runs and analysing the test results."},
        {"27a4485e4fe6dff5bcc1cc3093639e27c65c55c0", "This message has exactly 56 characters and that's tricky"}};

    const int garbage = 0xde;

    /* Test parsing valid sha1 strings. */
    {
        size_t stringNdx;

        for (stringNdx = 0; stringNdx < DE_LENGTH_OF_ARRAY(validHashStrings); stringNdx++)
        {
            deSha1 hash;
            deMemset(&hash, garbage, sizeof(deSha1));
            DE_TEST_ASSERT(deSha1_parse(&hash, validHashStrings[stringNdx]));
        }
    }

    /* Test parsing invalid sha1 strings. */
    {
        size_t stringNdx;

        for (stringNdx = 0; stringNdx < DE_LENGTH_OF_ARRAY(invalidHashStrings); stringNdx++)
        {
            deSha1 hash;
            deMemset(&hash, garbage, sizeof(deSha1));
            DE_TEST_ASSERT(!deSha1_parse(&hash, invalidHashStrings[stringNdx]));
        }
    }

    /* Compare valid hash strings for equality. */
    {
        size_t stringNdx;

        for (stringNdx = 0; stringNdx < DE_LENGTH_OF_ARRAY(validHashStrings); stringNdx++)
        {
            deSha1 hashA;
            deSha1 hashB;

            deMemset(&hashA, garbage, sizeof(deSha1));
            deMemset(&hashB, garbage, sizeof(deSha1));

            DE_TEST_ASSERT(deSha1_parse(&hashA, validHashStrings[stringNdx]));
            DE_TEST_ASSERT(deSha1_parse(&hashB, validHashStrings[stringNdx]));

            DE_TEST_ASSERT(deSha1_equal(&hashA, &hashA));
            DE_TEST_ASSERT(deSha1_equal(&hashA, &hashB));
            DE_TEST_ASSERT(deSha1_equal(&hashB, &hashA));
        }
    }

    /* Compare valid different hash strings for equality. */
    {
        size_t stringANdx;
        size_t stringBNdx;

        for (stringANdx = 0; stringANdx < DE_LENGTH_OF_ARRAY(validHashStrings); stringANdx++)
            for (stringBNdx = 0; stringBNdx < DE_LENGTH_OF_ARRAY(validHashStrings); stringBNdx++)
            {
                deSha1 hashA;
                deSha1 hashB;

                if (stringANdx == stringBNdx)
                    continue;

                deMemset(&hashA, garbage, sizeof(deSha1));
                deMemset(&hashB, garbage, sizeof(deSha1));

                DE_TEST_ASSERT(deSha1_parse(&hashA, validHashStrings[stringANdx]));
                DE_TEST_ASSERT(deSha1_parse(&hashB, validHashStrings[stringBNdx]));

                DE_TEST_ASSERT(!deSha1_equal(&hashA, &hashB));
                DE_TEST_ASSERT(!deSha1_equal(&hashB, &hashA));
            }
    }

    /* Test rendering hash as string. */
    {
        size_t stringNdx;

        for (stringNdx = 0; stringNdx < DE_LENGTH_OF_ARRAY(validHashStrings); stringNdx++)
        {
            char result[40];
            deSha1 hash;

            deMemset(&hash, garbage, sizeof(hash));
            deMemset(&result, garbage, sizeof(result));

            DE_TEST_ASSERT(deSha1_parse(&hash, validHashStrings[stringNdx]));
            deSha1_render(&hash, result);

            DE_TEST_ASSERT(strncmp(result, validHashStrings[stringNdx], 40) == 0);
        }
    }

    /* Test hash against few pre-computed cases. */
    {
        size_t ndx;

        for (ndx = 0; ndx < DE_LENGTH_OF_ARRAY(stringHashPairs); ndx++)
        {
            deSha1 result;
            deSha1 reference;

            deSha1_compute(&result, strlen(stringHashPairs[ndx].data), stringHashPairs[ndx].data);
            DE_TEST_ASSERT(deSha1_parse(&reference, stringHashPairs[ndx].hash));

            DE_TEST_ASSERT(deSha1_equal(&reference, &result));
        }
    }

    /* Test hash stream against few pre-computed cases. */
    {
        size_t ndx;

        for (ndx = 0; ndx < DE_LENGTH_OF_ARRAY(stringHashPairs); ndx++)
        {
            const char *const data = stringHashPairs[ndx].data;
            const size_t size      = strlen(data);

            deSha1Stream stream;
            deSha1 result;
            deSha1 reference;

            deSha1Stream_init(&stream);

            deSha1Stream_process(&stream, size / 2, data);
            deSha1Stream_process(&stream, size - (size / 2), data + size / 2);

            deSha1Stream_finalize(&stream, &result);

            deSha1_compute(&result, strlen(stringHashPairs[ndx].data), stringHashPairs[ndx].data);
            DE_TEST_ASSERT(deSha1_parse(&reference, stringHashPairs[ndx].hash));

            DE_TEST_ASSERT(deSha1_equal(&reference, &result));
        }
    }
}

DE_END_EXTERN_C