1/* Copyright (c) 2013-2015 Jeffrey Pfau
  2 *
  3 * This Source Code Form is subject to the terms of the Mozilla Public
  4 * License, v. 2.0. If a copy of the MPL was not distributed with this
  5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  6#include "util/vfs.h"
  7
  8#include "util/memory.h"
  9
 10#include <errno.h>
 11#include <stdio.h>
 12
 13struct VFileFILE {
 14	struct VFile d;
 15	FILE* file;
 16	bool writable;
 17};
 18
 19static bool _vffClose(struct VFile* vf);
 20static off_t _vffSeek(struct VFile* vf, off_t offset, int whence);
 21static ssize_t _vffRead(struct VFile* vf, void* buffer, size_t size);
 22static ssize_t _vffWrite(struct VFile* vf, const void* buffer, size_t size);
 23static void* _vffMap(struct VFile* vf, size_t size, int flags);
 24static void _vffUnmap(struct VFile* vf, void* memory, size_t size);
 25static void _vffTruncate(struct VFile* vf, size_t size);
 26static ssize_t _vffSize(struct VFile* vf);
 27
 28struct VFile* VFileFOpen(const char* path, const char* mode) {
 29	if (!path && !mode) {
 30		return 0;
 31	}
 32	FILE* file = fopen(path, mode);
 33	if (!file && errno == ENOENT && strcmp(mode, "r+b") == 0) {
 34		file = fopen(path, "w+b");
 35	}
 36	return VFileFromFILE(file);
 37}
 38
 39struct VFile* VFileFromFILE(FILE* file) {
 40	if (!file) {
 41		return 0;
 42	}
 43
 44	struct VFileFILE* vff = malloc(sizeof(struct VFileFILE));
 45	if (!vff) {
 46		return 0;
 47	}
 48
 49	vff->file = file;
 50	vff->writable = false;
 51	vff->d.close = _vffClose;
 52	vff->d.seek = _vffSeek;
 53	vff->d.read = _vffRead;
 54	vff->d.readline = VFileReadline;
 55	vff->d.write = _vffWrite;
 56	vff->d.map = _vffMap;
 57	vff->d.unmap = _vffUnmap;
 58	vff->d.truncate = _vffTruncate;
 59	vff->d.size = _vffSize;
 60
 61	return &vff->d;
 62}
 63
 64bool _vffClose(struct VFile* vf) {
 65	struct VFileFILE* vff = (struct VFileFILE*) vf;
 66	if (fclose(vff->file) < 0) {
 67		return false;
 68	}
 69	free(vff);
 70	return true;
 71}
 72
 73off_t _vffSeek(struct VFile* vf, off_t offset, int whence) {
 74	struct VFileFILE* vff = (struct VFileFILE*) vf;
 75	return fseek(vff->file, offset, whence);
 76}
 77
 78ssize_t _vffRead(struct VFile* vf, void* buffer, size_t size) {
 79	struct VFileFILE* vff = (struct VFileFILE*) vf;
 80	return fread(buffer, size, 1, vff->file);
 81}
 82
 83ssize_t _vffWrite(struct VFile* vf, const void* buffer, size_t size) {
 84	struct VFileFILE* vff = (struct VFileFILE*) vf;
 85	return fwrite(buffer, size, 1, vff->file);
 86}
 87
 88static void* _vffMap(struct VFile* vf, size_t size, int flags) {
 89	struct VFileFILE* vff = (struct VFileFILE*) vf;
 90	if (flags & MAP_WRITE) {
 91		vff->writable = true;
 92	}
 93	void* mem = anonymousMemoryMap(size);
 94	if (!mem) {
 95		return 0;
 96	}
 97	long pos = ftell(vff->file);
 98	fseek(vff->file, 0, SEEK_SET);
 99	fread(mem, size, 1, vff->file);
100	fseek(vff->file, pos, SEEK_SET);
101	return mem;
102}
103
104static void _vffUnmap(struct VFile* vf, void* memory, size_t size) {
105	struct VFileFILE* vff = (struct VFileFILE*) vf;
106	if (vff->writable) {
107		long pos = ftell(vff->file);
108		fseek(vff->file, 0, SEEK_SET);
109		fwrite(memory, size, 1, vff->file);
110		fseek(vff->file, pos, SEEK_SET);
111	}
112	mappedMemoryFree(memory, size);
113}
114
115static void _vffTruncate(struct VFile* vf, size_t size) {
116	struct VFileFILE* vff = (struct VFileFILE*) vf;
117	long pos = ftell(vff->file);
118	fseek(vff->file, 0, SEEK_END);
119	ssize_t realSize = ftell(vff->file);
120	if (realSize < 0) {
121		return;
122	}
123	while (size > (size_t) realSize) {
124		static const char zeros[128] = "";
125		size_t diff = size - realSize;
126		if (diff > sizeof(zeros)) {
127			diff = sizeof(zeros);
128		}
129		fwrite(zeros, diff, 1, vff->file);
130		realSize += diff;
131	}
132	fseek(vff->file, pos, SEEK_SET);
133}
134
135static ssize_t _vffSize(struct VFile* vf) {
136	struct VFileFILE* vff = (struct VFileFILE*) vf;
137	long pos = ftell(vff->file);
138	fseek(vff->file, 0, SEEK_END);
139	ssize_t size = ftell(vff->file);
140	fseek(vff->file, pos, SEEK_SET);
141	return size;
142}