c1bc70b711
A lot of files were missing copyright field in the header and
the Blender Foundation contributed to them in a sense of bug
fixing and general maintenance.
This change makes it explicit that those files are at least
partially copyrighted by the Blender Foundation.
Note that this does not make it so the Blender Foundation is
the only holder of the copyright in those files, and developers
who do not have a signed contract with the foundation still
hold the copyright as well.
Another aspect of this change is using SPDX format for the
header. We already used it for the license specification,
and now we state it for the copyright as well, following the
FAQ:
https://reuse.software/faq/
131 lines
3.0 KiB
C
131 lines
3.0 KiB
C
/* SPDX-FileCopyrightText: 2004-2021 Blender Foundation
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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/** \file
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* \ingroup bli
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*/
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#include <string.h>
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#include "BLI_blenlib.h"
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#include "BLI_filereader.h"
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#include "BLI_mmap.h"
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#include "MEM_guardedalloc.h"
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/* This file implements both memory-backed and memory-mapped-file-backed reading. */
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typedef struct {
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FileReader reader;
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const char *data;
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BLI_mmap_file *mmap;
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size_t length;
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} MemoryReader;
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static ssize_t memory_read_raw(FileReader *reader, void *buffer, size_t size)
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{
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MemoryReader *mem = (MemoryReader *)reader;
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/* Don't read more bytes than there are available in the buffer. */
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size_t readsize = MIN2(size, (size_t)(mem->length - mem->reader.offset));
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memcpy(buffer, mem->data + mem->reader.offset, readsize);
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mem->reader.offset += readsize;
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return readsize;
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}
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static off64_t memory_seek(FileReader *reader, off64_t offset, int whence)
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{
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MemoryReader *mem = (MemoryReader *)reader;
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off64_t new_pos;
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if (whence == SEEK_CUR) {
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new_pos = mem->reader.offset + offset;
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}
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else if (whence == SEEK_SET) {
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new_pos = offset;
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}
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else if (whence == SEEK_END) {
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new_pos = mem->length + offset;
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}
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else {
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return -1;
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}
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if (new_pos < 0 || new_pos > mem->length) {
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return -1;
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}
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mem->reader.offset = new_pos;
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return mem->reader.offset;
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}
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static void memory_close_raw(FileReader *reader)
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{
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MEM_freeN(reader);
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}
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FileReader *BLI_filereader_new_memory(const void *data, size_t len)
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{
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MemoryReader *mem = MEM_callocN(sizeof(MemoryReader), __func__);
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mem->data = (const char *)data;
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mem->length = len;
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mem->reader.read = memory_read_raw;
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mem->reader.seek = memory_seek;
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mem->reader.close = memory_close_raw;
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return (FileReader *)mem;
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}
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/* Memory-mapped file reading.
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* By using `mmap()`, we can map a file so that it can be treated like normal memory,
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* meaning that we can just read from it with `memcpy()` etc.
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* This avoids system call overhead and can significantly speed up file loading.
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*/
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static ssize_t memory_read_mmap(FileReader *reader, void *buffer, size_t size)
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{
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MemoryReader *mem = (MemoryReader *)reader;
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/* Don't read more bytes than there are available in the buffer. */
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size_t readsize = MIN2(size, (size_t)(mem->length - mem->reader.offset));
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if (!BLI_mmap_read(mem->mmap, buffer, mem->reader.offset, readsize)) {
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return 0;
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}
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mem->reader.offset += readsize;
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return readsize;
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}
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static void memory_close_mmap(FileReader *reader)
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{
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MemoryReader *mem = (MemoryReader *)reader;
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BLI_mmap_free(mem->mmap);
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MEM_freeN(mem);
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}
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FileReader *BLI_filereader_new_mmap(int filedes)
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{
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BLI_mmap_file *mmap = BLI_mmap_open(filedes);
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if (mmap == NULL) {
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return NULL;
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}
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MemoryReader *mem = MEM_callocN(sizeof(MemoryReader), __func__);
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mem->mmap = mmap;
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mem->length = BLI_lseek(filedes, 0, SEEK_END);
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mem->reader.read = memory_read_mmap;
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mem->reader.seek = memory_seek;
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mem->reader.close = memory_close_mmap;
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return (FileReader *)mem;
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}
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