#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h> // close()
#include <string.h> // strcpy, memset(), and memcpy()
#include <stdarg.h>
#include <errno.h> // errno, perror()
#include <stdbool.h>
//==================== 加密方法 sha1哈希 ====================
// SHA1 = SHA160 
typedef struct SHA1Context
{
    uint32_t Message_Digest[5];
    uint32_t Length_Low;
    uint32_t Length_High;
    uint8_t Message_Block[64];
    int32_t Message_Block_Index;
    int32_t Computed;
    int32_t Corrupted;
} SHA1Context;

#define SHA1CircularShift(bits, word) ((((word) << (bits)) & 0xFFFFFFFF) | ((word) >> (32 - (bits))))

static void SHA1ProcessMessageBlock(SHA1Context *context)
{
    const uint32_t K[] = {0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6};
    int32_t t;
    uint32_t temp;
    uint32_t W[80];
    uint32_t A, B, C, D, E;

    for (t = 0; t < 16; t++)
    {
        W[t] = ((uint32_t)context->Message_Block[t * 4]) << 24;
        W[t] |= ((uint32_t)context->Message_Block[t * 4 + 1]) << 16;
        W[t] |= ((uint32_t)context->Message_Block[t * 4 + 2]) << 8;
        W[t] |= ((uint32_t)context->Message_Block[t * 4 + 3]);
    }

    for (t = 16; t < 80; t++)
        W[t] = SHA1CircularShift(1, W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]);

    A = context->Message_Digest[0];
    B = context->Message_Digest[1];
    C = context->Message_Digest[2];
    D = context->Message_Digest[3];
    E = context->Message_Digest[4];

    for (t = 0; t < 20; t++)
    {
        temp = SHA1CircularShift(5, A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0];
        temp &= 0xFFFFFFFF;
        E = D;
        D = C;
        C = SHA1CircularShift(30, B);
        B = A;
        A = temp;
    }
    for (t = 20; t < 40; t++)
    {
        temp = SHA1CircularShift(5, A) + (B ^ C ^ D) + E + W[t] + K[1];
        temp &= 0xFFFFFFFF;
        E = D;
        D = C;
        C = SHA1CircularShift(30, B);
        B = A;
        A = temp;
    }
    for (t = 40; t < 60; t++)
    {
        temp = SHA1CircularShift(5, A) + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
        temp &= 0xFFFFFFFF;
        E = D;
        D = C;
        C = SHA1CircularShift(30, B);
        B = A;
        A = temp;
    }
    for (t = 60; t < 80; t++)
    {
        temp = SHA1CircularShift(5, A) + (B ^ C ^ D) + E + W[t] + K[3];
        temp &= 0xFFFFFFFF;
        E = D;
        D = C;
        C = SHA1CircularShift(30, B);
        B = A;
        A = temp;
    }
    context->Message_Digest[0] = (context->Message_Digest[0] + A) & 0xFFFFFFFF;
    context->Message_Digest[1] = (context->Message_Digest[1] + B) & 0xFFFFFFFF;
    context->Message_Digest[2] = (context->Message_Digest[2] + C) & 0xFFFFFFFF;
    context->Message_Digest[3] = (context->Message_Digest[3] + D) & 0xFFFFFFFF;
    context->Message_Digest[4] = (context->Message_Digest[4] + E) & 0xFFFFFFFF;
    context->Message_Block_Index = 0;
}

static void SHA1Reset(SHA1Context* context)
{
    context->Length_Low = 0;
    context->Length_High = 0;
    context->Message_Block_Index = 0;

    context->Message_Digest[0] = 0x67452301;
    context->Message_Digest[1] = 0xEFCDAB89;
    context->Message_Digest[2] = 0x98BADCFE;
    context->Message_Digest[3] = 0x10325476;
    context->Message_Digest[4] = 0xC3D2E1F0;

    context->Computed = 0;
    context->Corrupted = 0;
}

static void SHA1PadMessage(SHA1Context* context)
{
    if (context->Message_Block_Index > 55)
    {
        context->Message_Block[context->Message_Block_Index++] = 0x80;
        while (context->Message_Block_Index < 64)
            context->Message_Block[context->Message_Block_Index++] = 0;
        SHA1ProcessMessageBlock(context);
        while (context->Message_Block_Index < 56)
            context->Message_Block[context->Message_Block_Index++] = 0;
    }
    else
    {
        context->Message_Block[context->Message_Block_Index++] = 0x80;
        while (context->Message_Block_Index < 56)
            context->Message_Block[context->Message_Block_Index++] = 0;
    }
    context->Message_Block[56] = (context->Length_High >> 24) & 0xFF;
    context->Message_Block[57] = (context->Length_High >> 16) & 0xFF;
    context->Message_Block[58] = (context->Length_High >> 8) & 0xFF;
    context->Message_Block[59] = (context->Length_High) & 0xFF;
    context->Message_Block[60] = (context->Length_Low >> 24) & 0xFF;
    context->Message_Block[61] = (context->Length_Low >> 16) & 0xFF;
    context->Message_Block[62] = (context->Length_Low >> 8) & 0xFF;
    context->Message_Block[63] = (context->Length_Low) & 0xFF;

    SHA1ProcessMessageBlock(context);
}

static int32_t SHA1Result(SHA1Context* context)
{
    if (context->Corrupted)
    {
        return 0;
    }
    if (!context->Computed)
    {
        SHA1PadMessage(context);
        context->Computed = 1;
    }
    return 1;
}

static void SHA1Input(SHA1Context* context, const char* message_array, uint32_t length)
{
    if (!length)
        return;

    if (context->Computed || context->Corrupted)
    {
        context->Corrupted = 1;
        return;
    }

    while (length-- && !context->Corrupted)
    {
        context->Message_Block[context->Message_Block_Index++] = (*message_array & 0xFF);

        context->Length_Low += 8;

        context->Length_Low &= 0xFFFFFFFF;
        if (context->Length_Low == 0)
        {
            context->Length_High++;
            context->Length_High &= 0xFFFFFFFF;
            if (context->Length_High == 0)
                context->Corrupted = 1;
        }

        if (context->Message_Block_Index == 64)
        {
            SHA1ProcessMessageBlock(context);
        }
        message_array++;
    }
}

int SHA1_Hash(char* out, const char* xin)
{
    SHA1Context sha;
    char* buff = NULL;

    SHA1Reset(&sha);
    SHA1Input(&sha, xin, strlen(xin));

    if (!SHA1Result(&sha))
    {
        memset(out, 0, 40);
        printf("SHA1 ERROR: Could not compute message digest.\r\n");
    }
    else
    {
        sprintf(out, 
                "%08X%08X%08X%08X%08X",
                sha.Message_Digest[0],
                sha.Message_Digest[1],
                sha.Message_Digest[2],
                sha.Message_Digest[3],
                sha.Message_Digest[4]);
    }
    return 40;
}
