read.c

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/*****************************************************************************
 *   (c) 2020 Ledger SAS.
 *
 *  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.
 *****************************************************************************/
 
#include <stdint.h>  // uint*_t
#include <stddef.h>  // size_t
 
uint16_t read_u16_be(const uint8_t *ptr, size_t offset)
{
    return (uint16_t) ptr[offset + 0] << 8 |  //
           (uint16_t) ptr[offset + 1] << 0;
}
 
uint32_t read_u32_be(const uint8_t *ptr, size_t offset)
{
    return (uint32_t) ptr[offset + 0] << 24 |  //
           (uint32_t) ptr[offset + 1] << 16 |  //
           (uint32_t) ptr[offset + 2] << 8 |   //
           (uint32_t) ptr[offset + 3] << 0;
}
 
uint64_t read_u64_be(const uint8_t *ptr, size_t offset)
{
    return (uint64_t) ptr[offset + 0] << 56 |  //
           (uint64_t) ptr[offset + 1] << 48 |  //
           (uint64_t) ptr[offset + 2] << 40 |  //
           (uint64_t) ptr[offset + 3] << 32 |  //
           (uint64_t) ptr[offset + 4] << 24 |  //
           (uint64_t) ptr[offset + 5] << 16 |  //
           (uint64_t) ptr[offset + 6] << 8 |   //
           (uint64_t) ptr[offset + 7] << 0;
}
 
uint16_t read_u16_le(const uint8_t *ptr, size_t offset)
{
    return (uint16_t) ptr[offset + 0] << 0 |  //
           (uint16_t) ptr[offset + 1] << 8;
}
 
uint32_t read_u32_le(const uint8_t *ptr, size_t offset)
{
    return (uint32_t) ptr[offset + 0] << 0 |   //
           (uint32_t) ptr[offset + 1] << 8 |   //
           (uint32_t) ptr[offset + 2] << 16 |  //
           (uint32_t) ptr[offset + 3] << 24;
}
 
uint64_t read_u64_le(const uint8_t *ptr, size_t offset)
{
    return (uint64_t) ptr[offset + 0] << 0 |   //
           (uint64_t) ptr[offset + 1] << 8 |   //
           (uint64_t) ptr[offset + 2] << 16 |  //
           (uint64_t) ptr[offset + 3] << 24 |  //
           (uint64_t) ptr[offset + 4] << 32 |  //
           (uint64_t) ptr[offset + 5] << 40 |  //
           (uint64_t) ptr[offset + 6] << 48 |  //
           (uint64_t) ptr[offset + 7] << 56;
}