[안드로이드]Android OTA image verification 관련 SHA 초기화 부분

xref: /system/core/libmincrypt/sha.c

void SHA_init(SHA_CTX* ctx) {
    ctx->state[0] = 0x67452301;
    ctx->state[1] = 0xEFCDAB89;
    ctx->state[2] = 0x98BADCFE;
    ctx->state[3] = 0x10325476;
    ctx->state[4] = 0xC3D2E1F0;
    ctx->count = 0;
}

/system/core/include/mincrypt/sha.h

typedef struct SHA_CTX {
    uint64_t count;
    uint32_t state[5];
#if defined(HAVE_ENDIAN_H) && defined(HAVE_LITTLE_ENDIAN)
    union {
        uint8_t b[64];
        uint32_t w[16];
    } buf;
#else
    uint8_t buf[64];
#endif
} SHA_CTX;

xref: /system/core/libmincrypt/sha.c

void SHA_update(SHA_CTX* ctx, const void* data, int len) {
    int i = ctx->count % sizeof(ctx->buf);
    const uint8_t* p = (const uint8_t*)data;

    ctx->count += len;

    while (len > sizeof(ctx->buf) - i) {
        memcpy(&ctx->buf.b[i], p, sizeof(ctx->buf) - i);
        len -= sizeof(ctx->buf) - i;
        p += sizeof(ctx->buf) - i;
        SHA1_Transform(ctx);
        i = 0;
    }

    while (len--) {
        ctx->buf.b[i++] = *p++;
        if (i == sizeof(ctx->buf)) {
            SHA1_Transform(ctx);
            i = 0;
        }
    }
}