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CFAReader.cpp
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CFAReader.cpp
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#if !defined(_WIN32) && !defined(_WIN64)
#include <sys/types.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <stdint.h>
#else
typedef unsigned short uint16_t;
#endif
#include <errno.h>
#include <stdio.h> // for NULL
#include "CFAReader.h"
CFAReader::CFAReader()
#if defined(_WIN32) || defined(_WIN64)
: m_buf(NULL), m_fd(INVALID_HANDLE_VALUE),
#else
: m_buf((uint8_t *)MAP_FAILED), m_fd(-1),
#endif
m_filesz(0)
{
}
CFAReader::~CFAReader()
{
#if defined(_WIN32) || defined(_WIN64)
if (m_buf != NULL)
UnmapViewOfFile(m_buf);
if (m_map_handle != NULL)
CloseHandle(m_map_handle);
if (m_fd != INVALID_HANDLE_VALUE)
CloseHandle(m_fd);
#else
if (m_buf != MAP_FAILED) {
::munmap(m_buf, m_filesz);
m_buf = NULL;
}
if (m_fd != -1) {
::close(m_fd);
m_fd = -1;
}
#endif
}
int CFAReader::open(const char *fname, size_t expected_size)
{
#if defined(_WIN32) || defined(_WIN64)
m_fd =
CreateFile(fname, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (INVALID_HANDLE_VALUE == m_fd)
return GetLastError();
m_filesz = GetFileSize(m_fd, NULL);
if (INVALID_FILE_SIZE == m_filesz)
return GetLastError();
if (m_filesz != expected_size)
return EINVAL;
m_map_handle = CreateFileMapping(m_fd, NULL, PAGE_READONLY, 0, m_filesz, NULL);
if (NULL == m_map_handle)
return GetLastError();
m_buf = (uint8_t *)MapViewOfFile(m_map_handle, FILE_MAP_READ, 0, 0, 0);
if (NULL == m_buf)
return GetLastError();
#else
#ifdef O_NOATIME
m_fd = ::open(fname, O_NOATIME | O_RDONLY);
#else
m_fd = ::open(fname, O_RDONLY);
#endif
if (-1 == m_fd)
return errno;
m_filesz = expected_size;
#ifdef MAP_POPULATE
m_buf = (uint8_t *)::mmap(NULL, m_filesz, PROT_READ, MAP_PRIVATE | MAP_POPULATE, m_fd, 0);
#else
m_buf = (uint8_t *)::mmap(NULL, m_filesz, PROT_READ, MAP_PRIVATE, m_fd, 0);
#endif
if (MAP_FAILED == m_buf)
return errno;
posix_madvise(m_buf, m_filesz, POSIX_MADV_SEQUENTIAL);
#endif
return 0;
}
void CFAReader::read(uint8_t *out_buf, size_t x, size_t y, size_t stride)
{
uint8_t *bCurrByte = m_buf;
bool byteAligned = true;
for (size_t i = 0; i < y; ++i) {
for (size_t j = 0; j < x; ++j, out_buf += 2) {
if (byteAligned) {
// layout: 22223333 XXXX1111
out_buf[1] = bCurrByte[1] & 0x0F;
out_buf[0] = bCurrByte[0];
++bCurrByte;
} else {
#if defined(_WIN32) || defined(_WIN64)
_mm_prefetch((const CHAR *)bCurrByte + 2, _MM_HINT_T0);
#endif
#if defined(__GNUC__)
__builtin_prefetch(bCurrByte + 2);
#endif
// layout: 3333XXXX 11112222
out_buf[1] = (uint8_t)(bCurrByte[1] >> 4);
out_buf[0] = (uint8_t)((bCurrByte[1] << 4) | (bCurrByte[0] >> 4));
bCurrByte += 2;
}
byteAligned = !byteAligned;
}
bCurrByte += stride;
byteAligned = true;
}
}
void CFAReader::read(uint8_t *out_buf, size_t total)
{
uint8_t *bCurrByte = m_buf;
bool byteAligned = true;
for (size_t i = 0; i < total; ++i, out_buf += 2) {
if (byteAligned) {
// layout: 22223333 XXXX1111
out_buf[1] = bCurrByte[1] & 0x0F;
out_buf[0] = bCurrByte[0];
++bCurrByte;
} else {
#if defined(_WIN32) || defined(_WIN64)
_mm_prefetch((const CHAR *)bCurrByte + 2, _MM_HINT_T0);
#endif
#if defined(__GNUC__)
__builtin_prefetch(bCurrByte + 2);
#endif
// layout: 3333XXXX 11112222
out_buf[1] = (uint8_t)(bCurrByte[1] >> 4);
out_buf[0] = (uint8_t)((bCurrByte[1] << 4) | (bCurrByte[0] >> 4));
bCurrByte += 2;
}
byteAligned = !byteAligned;
}
}