/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
 * common.c
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 */
#define SQFS_BUILDING_DLL
#include "internal.h"

static int set_block_size(sqfs_inode_generic_t **inode,
			  sqfs_u32 index, sqfs_u32 size)
{
	size_t min_size = (index + 1) * sizeof(sqfs_u32);
	size_t avail = (*inode)->payload_bytes_available;
	size_t newsz;
	void *new;

	if (avail < min_size) {
		newsz = avail ? avail : (sizeof(sqfs_u32) * 4);
		while (newsz < min_size)
			newsz *= 2;

		if (SZ_ADD_OV(newsz, sizeof(**inode), &newsz))
			return SQFS_ERROR_OVERFLOW;

		if (sizeof(size_t) > sizeof(sqfs_u32)) {
			if ((newsz - sizeof(**inode)) > 0x0FFFFFFFFUL)
				return SQFS_ERROR_OVERFLOW;
		}

		new = realloc((*inode), newsz);
		if (new == NULL)
			return SQFS_ERROR_ALLOC;

		(*inode) = new;
		(*inode)->payload_bytes_available = newsz - sizeof(**inode);
	}

	(*inode)->extra[index] = size;

	if (min_size >= (*inode)->payload_bytes_used)
		(*inode)->payload_bytes_used = min_size;

	return 0;
}

int process_completed_block(sqfs_block_processor_t *proc, sqfs_block_t *blk)
{
	sqfs_u64 location;
	sqfs_u32 size;
	int err;

	err = sqfs_block_writer_write(proc->wr, blk->size, blk->checksum,
				      blk->flags, blk->data, &location);
	if (err)
		return err;

	if (blk->flags & SQFS_BLK_IS_SPARSE) {
		sqfs_inode_make_extended(*(blk->inode));
		(*(blk->inode))->data.file_ext.sparse += blk->size;

		err = set_block_size(blk->inode, blk->index, 0);
		if (err)
			return err;

		proc->stats.sparse_block_count += 1;
	} else if (blk->size != 0) {
		size = blk->size;
		if (!(blk->flags & SQFS_BLK_IS_COMPRESSED))
			size |= 1 << 24;

		if (blk->flags & SQFS_BLK_FRAGMENT_BLOCK) {
			err = sqfs_frag_table_set(proc->frag_tbl, blk->index,
						  location, size);
			if (err)
				return err;
		} else {
			err = set_block_size(blk->inode, blk->index, size);
			if (err)
				return err;
			proc->stats.data_block_count += 1;
		}
	}

	if (blk->flags & SQFS_BLK_LAST_BLOCK)
		sqfs_inode_set_file_block_start(*(blk->inode), location);

	return 0;
}

static bool is_zero_block(unsigned char *ptr, size_t size)
{
	return ptr[0] == 0 && memcmp(ptr, ptr + 1, size - 1) == 0;
}

int block_processor_do_block(sqfs_block_t *block, sqfs_compressor_t *cmp,
			     sqfs_u8 *scratch, size_t scratch_size)
{
	sqfs_s32 ret;

	if (block->size == 0)
		return 0;

	if (is_zero_block(block->data, block->size)) {
		block->flags |= SQFS_BLK_IS_SPARSE;
		return 0;
	}

	block->checksum = xxh32(block->data, block->size);

	if (block->flags & (SQFS_BLK_IS_FRAGMENT | SQFS_BLK_DONT_COMPRESS))
		return 0;

	ret = cmp->do_block(cmp, block->data, block->size,
			    scratch, scratch_size);
	if (ret < 0)
		return ret;

	if (ret > 0) {
		memcpy(block->data, scratch, ret);
		block->size = ret;
		block->flags |= SQFS_BLK_IS_COMPRESSED;
	}
	return 0;
}

int process_completed_fragment(sqfs_block_processor_t *proc, sqfs_block_t *frag,
			       sqfs_block_t **blk_out)
{
	sqfs_u32 index, offset;
	size_t size;
	int err;

	if (frag->flags & SQFS_BLK_IS_SPARSE) {
		sqfs_inode_make_extended(*(frag->inode));
		set_block_size(frag->inode, frag->index, 0);
		(*(frag->inode))->data.file_ext.sparse += frag->size;

		proc->stats.sparse_block_count += 1;
		return 0;
	}

	proc->stats.total_frag_count += 1;

	err = sqfs_frag_table_find_tail_end(proc->frag_tbl, frag->checksum,
					    frag->size, &index, &offset);
	if (err == 0) {
		sqfs_inode_set_frag_location(*(frag->inode), index, offset);
		return 0;
	}

	if (proc->frag_block != NULL) {
		size = proc->frag_block->size + frag->size;

		if (size > proc->max_block_size) {
			*blk_out = proc->frag_block;
			proc->frag_block = NULL;
		}
	}

	if (proc->frag_block == NULL) {
		size = sizeof(sqfs_block_t) + proc->max_block_size;

		err= sqfs_frag_table_append(proc->frag_tbl, 0, 0, &index);
		if (err)
			goto fail;

		proc->frag_block = calloc(1, size);
		if (proc->frag_block == NULL) {
			err = SQFS_ERROR_ALLOC;
			goto fail;
		}

		proc->frag_block->index = index;
		proc->frag_block->flags = SQFS_BLK_FRAGMENT_BLOCK;
		proc->stats.frag_block_count += 1;
	}

	err = sqfs_frag_table_add_tail_end(proc->frag_tbl,
					   proc->frag_block->index,
					   proc->frag_block->size,
					   frag->size, frag->checksum);
	if (err)
		goto fail;

	sqfs_inode_set_frag_location(*(frag->inode), proc->frag_block->index,
				     proc->frag_block->size);

	memcpy(proc->frag_block->data + proc->frag_block->size,
	       frag->data, frag->size);

	proc->frag_block->flags |= (frag->flags & SQFS_BLK_DONT_COMPRESS);
	proc->frag_block->size += frag->size;
	proc->stats.actual_frag_count += 1;
	return 0;
fail:
	free(*blk_out);
	*blk_out = NULL;
	return err;
}

static int add_sentinel_block(sqfs_block_processor_t *proc)
{
	sqfs_block_t *blk = calloc(1, sizeof(*blk));

	if (blk == NULL)
		return SQFS_ERROR_ALLOC;

	blk->inode = proc->inode;
	blk->flags = proc->blk_flags | SQFS_BLK_LAST_BLOCK;

	return append_to_work_queue(proc, blk);
}

static int flush_block(sqfs_block_processor_t *proc)
{
	sqfs_block_t *block = proc->blk_current;

	proc->blk_current = NULL;

	if (block->size < proc->max_block_size &&
	    !(block->flags & SQFS_BLK_DONT_FRAGMENT)) {
		block->flags |= SQFS_BLK_IS_FRAGMENT;
	} else {
		proc->blk_flags &= ~SQFS_BLK_FIRST_BLOCK;
	}

	block->index = proc->blk_index++;
	return append_to_work_queue(proc, block);
}

int sqfs_block_processor_begin_file(sqfs_block_processor_t *proc,
				    sqfs_inode_generic_t **inode, sqfs_u32 flags)
{
	if (proc->inode != NULL)
		return SQFS_ERROR_SEQUENCE;

	if (flags & ~SQFS_BLK_USER_SETTABLE_FLAGS)
		return SQFS_ERROR_UNSUPPORTED;

	(*inode) = calloc(1, sizeof(sqfs_inode_generic_t));
	if ((*inode) == NULL)
		return SQFS_ERROR_ALLOC;

	(*inode)->base.type = SQFS_INODE_FILE;
	sqfs_inode_set_frag_location(*inode, 0xFFFFFFFF, 0xFFFFFFFF);

	proc->inode = inode;
	proc->blk_flags = flags | SQFS_BLK_FIRST_BLOCK;
	proc->blk_index = 0;
	return 0;
}

int sqfs_block_processor_append(sqfs_block_processor_t *proc, const void *data,
				size_t size)
{
	sqfs_block_t *new;
	sqfs_u64 filesize;
	size_t diff;
	int err;

	sqfs_inode_get_file_size(*(proc->inode), &filesize);
	sqfs_inode_set_file_size(*(proc->inode), filesize + size);

	while (size > 0) {
		if (proc->blk_current == NULL) {
			new = alloc_flex(sizeof(*new), 1, proc->max_block_size);
			if (new == NULL)
				return SQFS_ERROR_ALLOC;

			proc->blk_current = new;
			proc->blk_current->flags = proc->blk_flags;
			proc->blk_current->inode = proc->inode;
		}

		diff = proc->max_block_size - proc->blk_current->size;

		if (diff == 0) {
			err = flush_block(proc);
			if (err)
				return err;
			continue;
		}

		if (diff > size)
			diff = size;

		memcpy(proc->blk_current->data + proc->blk_current->size,
		       data, diff);

		size -= diff;
		proc->blk_current->size += diff;
		data = (const char *)data + diff;

		proc->stats.input_bytes_read += diff;
	}

	if (proc->blk_current != NULL &&
	    proc->blk_current->size == proc->max_block_size) {
		return flush_block(proc);
	}

	return 0;
}

int sqfs_block_processor_end_file(sqfs_block_processor_t *proc)
{
	int err;

	if (proc->inode == NULL)
		return SQFS_ERROR_SEQUENCE;

	if (!(proc->blk_flags & SQFS_BLK_FIRST_BLOCK)) {
		if (proc->blk_current != NULL &&
		    (proc->blk_flags & SQFS_BLK_DONT_FRAGMENT)) {
			proc->blk_flags |= SQFS_BLK_LAST_BLOCK;
		} else {
			err = add_sentinel_block(proc);
			if (err)
				return err;
		}
	}

	if (proc->blk_current != NULL) {
		err = flush_block(proc);
		if (err)
			return err;
	}

	proc->inode = NULL;
	proc->blk_flags = 0;
	return 0;
}

const sqfs_block_processor_stats_t
*sqfs_block_processor_get_stats(const sqfs_block_processor_t *proc)
{
	return &proc->stats;
}