file.c

#include "file.h"

static FileData load_file(FileHandle32 handle, u32 padding) {
	FileData result = { 0 };

	u64 file_size = query_file_size(handle);
	result.data = alloc_virtual_page(file_size + padding);
	result.size = read_file(handle, result.data, file_size);
	zero(result.data+result.size, 8);

	return result;
}

// ------------------------------------ //

typedef struct Linux_DirectoryEntry64 {
	u64  inode;
	s64  offset;
	u16  length;
	u8   type;
	char name[];
} Linux_DirectoryEntry64;

// void experiment_virtual_pages(void) {
// 	u64* a = (u64*)system_call(LINUX_SYSCALL_MMAP, 0, 4096, 3, 0x21, -1, 0);
// 	*a = 1;
// 	print("*a = %, address = %\n", arg_u64(*a), arg_u64((u64)a));

// 	u64* b = (u64*)system_call(LINUX_SYSCALL_MMAP, 0, 4096, 3, 0x21, -1, 0);
// 	*b = 2;
// 	print("*b = %, address = %\n", arg_u64(*b), arg_u64((u64)b));

// 	u64* c = (u64*)system_call(LINUX_SYSCALL_MREMAP, (u64)b, 4096, 4096, 1|2|4, (u64)a, 0);

// 	print("*a = %, address = %\n", arg_u64(*a), arg_u64((u64)a));
// 	print("*b = %, address = %\n", arg_u64(*b), arg_u64((u64)b));

// 	*b = 3;
// 	print("*a = %, address = %\n", arg_u64(*a), arg_u64((u64)a));
// 	print("*b = %, address = %\n", arg_u64(*b), arg_u64((u64)b));
// }

// static void list_dir(char* dir) {
// 	u64 dirlen = count_cstring(dir);

// 	if (!dirlen) {
// 		dir = "./";
// 		dirlen = 2;
// 	}

// 	FileHandle32 dir_handle = open_file(tostr(dir), FILE_MODE_DIRECTORY, FILE_ACCESS_FLAG_READ);

// 	if (dir_handle == -1) {
// 		print("Invalid directory file handle.\n");
// 		return;
// 	}

// 	#define BUFFER_SIZE 8192
// 	char buffer[BUFFER_SIZE] = { 0 };
// 	char* p;

// 	u64 loc = 0;
// 	while (true) {
// 		p = buffer;
// 		s64 read = system_call(LINUX_SYSCALL_GETDENTS64, dir_handle, (u64)buffer, BUFFER_SIZE, 0, 0, 0);
// 		if (!read) break;

// 		if (read == -1) {
// 			print("Error reading dirs\n");
// 			return;
// 		}

// 		print("read = %\n", arg_s64(read));

// 		while (p < buffer+read) {
// 			Linux_DirectoryEntry64* entry = (Linux_DirectoryEntry64*)p;

// 			u64 name_len = count_cstring(entry->name);
// 			if (name_len >= 3 && compare(entry->name+name_len-2, ".c", 2)) {
// 				print("name = %, type = %, length = %, inode = %, offset = %\n",
// 					arg_cstring(entry->name),
// 					arg_u8(entry->type),
// 					arg_u16(entry->length),
// 					arg_u64(entry->inode),
// 					arg_s64(entry->offset)
// 				);

// 				char path[dirlen+name_len+2];
// 				char* g = path;
// 				copy(g, dir, dirlen);
// 				g += dirlen;

// 				if (g[-1] != '/') {
// 					*g = '/';
// 					g += 1;
// 				}

// 				copy(g, entry->name, name_len);
// 				g += name_len;
// 				*g = 0;
// 			}

// 			p += entry->length;
// 		}
// 	}
// }

// ------------------------------------ //

static void flush_output_buffer(OutputBuffer* buffer) {
	if (!buffer->head)
		return;

	write_file(buffer->file_handle, buffer->buffer, buffer->head);
	buffer->flush_count++;
	buffer->flushed_bytes += buffer->head;
	buffer->head = 0;
}

static void write_output_buffer(OutputBuffer* buffer, const byte* data, u64 length) {
	buffer->written_bytes += length;

	if (buffer->head + length < OUTPUT_BUFFER_SIZE) {
		copy(buffer->buffer + buffer->head, data, length);
		buffer->head += length;
		return;
	}

	if (buffer->head + length < OUTPUT_BUFFER_SIZE*2) {
		u64 precopy_size = OUTPUT_BUFFER_SIZE - buffer->head;
		copy(buffer->buffer + buffer->head, data, precopy_size);
		buffer->head = OUTPUT_BUFFER_SIZE;
		flush_output_buffer(buffer);

		u64 postcopy_size = length - precopy_size;
		copy(buffer->buffer, data+precopy_size, postcopy_size);
		buffer->head = postcopy_size;
		return;
	}

	flush_output_buffer(buffer);
	write_file(buffer->file_handle, data, length);
	buffer->flush_count++;
	buffer->flushed_bytes += length;
}

static void write_output_buffer_b(OutputBuffer* buffer, byte b) {
	if (buffer->head >= OUTPUT_BUFFER_SIZE)
		flush_output_buffer(buffer);

	buffer->buffer[buffer->head] = b;
	buffer->head += 1;
	buffer->written_bytes += 1;
}