mlx/mlx/io/load.cpp
2024-01-06 12:44:02 -08:00

248 lines
7.0 KiB
C++

// Copyright © 2023 Apple Inc.
#include <algorithm>
#include <cstring>
#include <fstream>
#include <limits>
#include <sstream>
#include "mlx/io/load.h"
#include "mlx/ops.h"
#include "mlx/primitives.h"
#include "mlx/utils.h"
// Adapted from
// https://github.com/angeloskath/supervised-lda/blob/master/include/ldaplusplus/NumpyFormat.hpp
namespace mlx::core {
namespace {
static constexpr uint8_t MAGIC[] = {
0x93,
0x4e,
0x55,
0x4d,
0x50,
0x59,
};
inline bool is_big_endian_() {
union ByteOrder {
int32_t i;
uint8_t c[4];
};
ByteOrder b = {0x01234567};
return b.c[0] == 0x01;
}
} // namespace
/** Save array to out stream in .npy format */
void save(std::shared_ptr<io::Writer> out_stream, array a, bool retain_graph) {
////////////////////////////////////////////////////////
// Check array
a.eval(retain_graph);
if (a.nbytes() == 0) {
throw std::invalid_argument("[save] cannot serialize an empty array");
}
if (!(a.flags().row_contiguous || a.flags().col_contiguous)) {
a = reshape(flatten(a), a.shape());
a.eval(retain_graph);
}
// Check once more in-case the above ops change
if (!(a.flags().row_contiguous || a.flags().col_contiguous)) {
throw std::invalid_argument(
"[save] can only serialize row or col contiguous arrays");
}
////////////////////////////////////////////////////////
// Check file
if (!out_stream->good() || !out_stream->is_open()) {
throw std::runtime_error("[save] Failed to open " + out_stream->label());
}
////////////////////////////////////////////////////////
// Prepare header
std::ostringstream magic_ver_len;
magic_ver_len.write(reinterpret_cast<const char*>(MAGIC), 6);
std::string fortran_order = a.flags().col_contiguous ? "True" : "False";
std::ostringstream header;
header << "{'descr': '" << dtype_to_array_protocol(a.dtype()) << "',"
<< " 'fortran_order': " << fortran_order << ","
<< " 'shape': (";
for (auto i : a.shape()) {
header << i << ", ";
}
header << ")}";
size_t header_len = static_cast<size_t>(header.tellp());
bool is_v1 = header_len + 15 < std::numeric_limits<uint16_t>::max();
// Pad out magic + version + header_len + header + \n to be divisible by 16
size_t padding = (6 + 2 + (2 + 2 * is_v1) + header_len + 1) % 16;
header << std::string(padding, ' ') << '\n';
if (is_v1) {
magic_ver_len << (char)0x01 << (char)0x00;
uint16_t v1_header_len = header.tellp();
const char* len_bytes = reinterpret_cast<const char*>(&v1_header_len);
if (!is_big_endian_()) {
magic_ver_len.write(len_bytes, 2);
} else {
magic_ver_len.write(len_bytes + 1, 1);
magic_ver_len.write(len_bytes, 1);
}
} else {
magic_ver_len << (char)0x02 << (char)0x00;
uint32_t v2_header_len = header.tellp();
const char* len_bytes = reinterpret_cast<const char*>(&v2_header_len);
if (!is_big_endian_()) {
magic_ver_len.write(len_bytes, 4);
} else {
magic_ver_len.write(len_bytes + 3, 1);
magic_ver_len.write(len_bytes + 2, 1);
magic_ver_len.write(len_bytes + 1, 1);
magic_ver_len.write(len_bytes, 1);
}
}
////////////////////////////////////////////////////////
// Serialize array
out_stream->write(magic_ver_len.str().c_str(), magic_ver_len.str().length());
out_stream->write(header.str().c_str(), header.str().length());
out_stream->write(a.data<char>(), a.nbytes());
return;
}
/** Save array to file in .npy format */
void save(const std::string& file_, array a, bool retain_graph) {
// Open and check file
std::string file = file_;
// Add .npy to file name if it is not there
if (file.length() < 4 || file.substr(file.length() - 4, 4) != ".npy")
file += ".npy";
// Serialize array
save(std::make_shared<io::FileWriter>(file), a, retain_graph);
}
/** Load array from reader in .npy format */
array load(std::shared_ptr<io::Reader> in_stream, StreamOrDevice s) {
////////////////////////////////////////////////////////
// Open and check file
if (!in_stream->good() || !in_stream->is_open()) {
throw std::runtime_error("[load] Failed to open " + in_stream->label());
}
////////////////////////////////////////////////////////
// Read header and prepare array details
// Read and check magic
char read_magic_and_ver[8];
in_stream->read(read_magic_and_ver, 8);
if (std::memcmp(read_magic_and_ver, MAGIC, 6) != 0) {
throw std::runtime_error("[load] Invalid header in " + in_stream->label());
}
// Read and check version
if (read_magic_and_ver[6] != 1 && read_magic_and_ver[6] != 2) {
throw std::runtime_error(
"[load] Unsupported npy format version in " + in_stream->label());
}
// Read header len and header
int header_len_size = read_magic_and_ver[6] == 1 ? 2 : 4;
size_t header_len;
if (header_len_size == 2) {
uint16_t v1_header_len;
in_stream->read(reinterpret_cast<char*>(&v1_header_len), header_len_size);
header_len = v1_header_len;
} else {
uint32_t v2_header_len;
in_stream->read(reinterpret_cast<char*>(&v2_header_len), header_len_size);
header_len = v2_header_len;
}
// Read the header
std::vector<char> buffer(header_len + 1);
in_stream->read(&buffer[0], header_len);
buffer[header_len] = 0;
std::string header(&buffer[0]);
// Read data type from header
std::string dtype_str = header.substr(11, 3);
bool read_is_big_endian = dtype_str[0] == '>';
Dtype dtype = dtype_from_array_protocol(dtype_str);
// Read contiguity order
bool col_contiguous = header[34] == 'T';
// Read array shape from header
std::vector<int> shape;
size_t st = header.find_last_of('(') + 1;
size_t ed = header.find_last_of(')');
std::string shape_str = header.substr(st, ed - st);
while (!shape_str.empty()) {
// Read current number and get position of comma
size_t pos;
int dim = std::stoi(shape_str, &pos);
shape.push_back(dim);
// Skip the comma and space and read the next number
if (pos + 2 <= shape_str.length())
shape_str = shape_str.substr(pos + 2);
else {
shape_str = shape_str.substr(pos);
if (!shape_str.empty() && shape_str != " " && shape_str != ",") {
throw std::runtime_error(
"[load] Unknown error while parsing header in " +
in_stream->label());
}
shape_str = "";
}
}
////////////////////////////////////////////////////////
// Build primitive
size_t offset = 8 + header_len_size + header.length();
bool swap_endianness = read_is_big_endian != is_big_endian_();
if (col_contiguous) {
std::reverse(shape.begin(), shape.end());
}
auto loaded_array = array(
shape,
dtype,
std::make_unique<Load>(to_stream(s), in_stream, offset, swap_endianness),
std::vector<array>{});
if (col_contiguous) {
loaded_array = transpose(loaded_array, s);
}
return loaded_array;
}
/** Load array from file in .npy format */
array load(const std::string& file, StreamOrDevice s) {
return load(std::make_shared<io::FileReader>(file), s);
}
} // namespace mlx::core