#include "mupdf/fitz.h"
#include "fitz-imp.h"

#include <string.h>
#include <assert.h>

// Thoughts for further optimisations:
// All paths start with MoveTo. We could probably avoid most cases where
// we store that. The next thing after a close must be a move.
// Commands are MOVE, LINE, HORIZ, VERT, DEGEN, CURVE, CURVEV, CURVEY, QUAD, RECT.
// We'd need to drop 2 to get us down to 3 bits.
// Commands can be followed by CLOSE. Use 1 bit for close.
// PDF 'RECT' implies close according to the spec, but I suspect
// we can ignore this as filling closes implicitly.
// We use a single bit in the path header to tell us whether we have
// a trailing move. Trailing moves can always be stripped when path
// construction completes.

typedef enum fz_path_command_e
{
	FZ_MOVETO = 'M',
	FZ_LINETO = 'L',
	FZ_DEGENLINETO = 'D',
	FZ_CURVETO = 'C',
	FZ_CURVETOV = 'V',
	FZ_CURVETOY = 'Y',
	FZ_HORIZTO = 'H',
	FZ_VERTTO = 'I',
	FZ_QUADTO = 'Q',
	FZ_RECTTO = 'R',
	FZ_MOVETOCLOSE = 'm',
	FZ_LINETOCLOSE = 'l',
	FZ_DEGENLINETOCLOSE = 'd',
	FZ_CURVETOCLOSE = 'c',
	FZ_CURVETOVCLOSE = 'v',
	FZ_CURVETOYCLOSE = 'y',
	FZ_HORIZTOCLOSE = 'h',
	FZ_VERTTOCLOSE = 'i',
	FZ_QUADTOCLOSE = 'q',
} fz_path_item_kind;

struct fz_path_s
{
	int8_t refs;
	uint8_t packed;
	int cmd_len, cmd_cap;
	unsigned char *cmds;
	int coord_len, coord_cap;
	float *coords;
	fz_point current;
	fz_point begin;
};

typedef struct fz_packed_path_s
{
	int8_t refs;
	uint8_t packed;
	uint8_t coord_len;
	uint8_t cmd_len;
} fz_packed_path;

enum
{
	FZ_PATH_UNPACKED = 0,
	FZ_PATH_PACKED_FLAT = 1,
	FZ_PATH_PACKED_OPEN = 2
};

#define LAST_CMD(path) ((path)->cmd_len > 0 ? (path)->cmds[(path)->cmd_len-1] : 0)

fz_path *
fz_new_path(fz_context *ctx)
{
	fz_path *path;

	path = fz_malloc_struct(ctx, fz_path);
	path->refs = 1;
	path->packed = FZ_PATH_UNPACKED;
	path->current.x = 0;
	path->current.y = 0;
	path->begin.x = 0;
	path->begin.y = 0;

	return path;
}

fz_path *
fz_keep_path(fz_context *ctx, const fz_path *pathc)
{
	fz_path *path = (fz_path *)pathc; /* Explicit cast away of const */

	if (path == NULL)
		return NULL;
	if (path->refs == 1 && path->packed == FZ_PATH_UNPACKED)
		fz_trim_path(ctx, path);
	return fz_keep_imp8(ctx, path, &path->refs);
}

void
fz_drop_path(fz_context *ctx, const fz_path *pathc)
{
	fz_path *path = (fz_path *)pathc; /* Explicit cast away of const */

	if (fz_drop_imp8(ctx, path, &path->refs))
	{
		if (path->packed != FZ_PATH_PACKED_FLAT)
		{
			fz_free(ctx, path->cmds);
			fz_free(ctx, path->coords);
		}
		if (path->packed == FZ_PATH_UNPACKED)
			fz_free(ctx, path);
	}
}

int fz_packed_path_size(const fz_path *path)
{
	switch (path->packed)
	{
	case FZ_PATH_UNPACKED:
		if (path->cmd_len > 255 || path->coord_len > 255)
			return sizeof(fz_path);
		return sizeof(fz_packed_path) + sizeof(float) * path->coord_len + sizeof(uint8_t) * path->cmd_len;
	case FZ_PATH_PACKED_OPEN:
		return sizeof(fz_path);
	case FZ_PATH_PACKED_FLAT:
	{
		fz_packed_path *pack = (fz_packed_path *)path;
		return sizeof(fz_packed_path) + sizeof(float) * pack->coord_len + sizeof(uint8_t) * pack->cmd_len;
	}
	default:
		assert("This never happens" == NULL);
		return 0;
	}
}

int
fz_pack_path(fz_context *ctx, uint8_t *pack_, int max, const fz_path *path)
{
	uint8_t *ptr;
	int size;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Can't repack a packed path");

	size = sizeof(fz_packed_path) + sizeof(float) * path->coord_len + sizeof(uint8_t) * path->cmd_len;

	/* If the path can't be packed flat, then pack it open */
	if (path->cmd_len > 255 || path->coord_len > 255 || size > max)
	{
		fz_path *pack = (fz_path *)pack_;

		if (sizeof(fz_path) > max)
			fz_throw(ctx, FZ_ERROR_GENERIC, "Can't pack a path that small!");

		if (pack != NULL)
		{
			pack->refs = 1;
			pack->packed = FZ_PATH_PACKED_OPEN;
			pack->current.x = 0;
			pack->current.y = 0;
			pack->begin.x = 0;
			pack->begin.y = 0;
			pack->coord_cap = path->coord_len;
			pack->coord_len = path->coord_len;
			pack->cmd_cap = path->cmd_len;
			pack->cmd_len = path->cmd_len;
			pack->coords = fz_malloc_array(ctx, path->coord_len, sizeof(float));
			fz_try(ctx)
			{
				pack->cmds = fz_malloc_array(ctx, path->cmd_len, sizeof(uint8_t));
			}
			fz_catch(ctx)
			{
				fz_free(ctx, pack->coords);
				fz_rethrow(ctx);
			}
			memcpy(pack->coords, path->coords, sizeof(float) * path->coord_len);
			memcpy(pack->cmds, path->cmds, sizeof(uint8_t) * path->cmd_len);
		}
		return sizeof(fz_path);
	}
	else
	{
		fz_packed_path *pack = (fz_packed_path *)pack_;

		if (pack != NULL)
		{
			pack->refs = 1;
			pack->packed = FZ_PATH_PACKED_FLAT;
			pack->cmd_len = path->cmd_len;
			pack->coord_len = path->coord_len;
			ptr = (uint8_t *)&pack[1];
			memcpy(ptr, path->coords, sizeof(float) * path->coord_len);
			ptr += sizeof(float) * path->coord_len;
			memcpy(ptr, path->cmds, sizeof(uint8_t) * path->cmd_len);
		}

		return size;
	}
}

static void
push_cmd(fz_context *ctx, fz_path *path, int cmd)
{
	if (path->refs != 1)
		fz_throw(ctx, FZ_ERROR_GENERIC, "cannot modify shared paths");

	if (path->cmd_len + 1 >= path->cmd_cap)
	{
		int new_cmd_cap = fz_maxi(16, path->cmd_cap * 2);
		path->cmds = fz_resize_array(ctx, path->cmds, new_cmd_cap, sizeof(unsigned char));
		path->cmd_cap = new_cmd_cap;
	}

	path->cmds[path->cmd_len++] = cmd;
}

static void
push_coord(fz_context *ctx, fz_path *path, float x, float y)
{
	if (path->coord_len + 2 >= path->coord_cap)
	{
		int new_coord_cap = fz_maxi(32, path->coord_cap * 2);
		path->coords = fz_resize_array(ctx, path->coords, new_coord_cap, sizeof(float));
		path->coord_cap = new_coord_cap;
	}

	path->coords[path->coord_len++] = x;
	path->coords[path->coord_len++] = y;

	path->current.x = x;
	path->current.y = y;
}

static void
push_ord(fz_context *ctx, fz_path *path, float xy, int isx)
{
	if (path->coord_len + 1 >= path->coord_cap)
	{
		int new_coord_cap = fz_maxi(32, path->coord_cap * 2);
		path->coords = fz_resize_array(ctx, path->coords, new_coord_cap, sizeof(float));
		path->coord_cap = new_coord_cap;
	}

	path->coords[path->coord_len++] = xy;

	if (isx)
		path->current.x = xy;
	else
		path->current.y = xy;
}

fz_point
fz_currentpoint(fz_context *ctx, fz_path *path)
{
	return path->current;
}

void
fz_moveto(fz_context *ctx, fz_path *path, float x, float y)
{
	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	if (path->cmd_len > 0 && LAST_CMD(path) == FZ_MOVETO)
	{
		/* Collapse moveto followed by moveto. */
		path->coords[path->coord_len-2] = x;
		path->coords[path->coord_len-1] = y;
		path->current.x = x;
		path->current.y = y;
		path->begin = path->current;
		return;
	}

	push_cmd(ctx, path, FZ_MOVETO);
	push_coord(ctx, path, x, y);

	path->begin = path->current;
}

void
fz_lineto(fz_context *ctx, fz_path *path, float x, float y)
{
	float x0, y0;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	x0 = path->current.x;
	y0 = path->current.y;

	if (path->cmd_len == 0)
	{
		fz_warn(ctx, "lineto with no current point");
		return;
	}

	/* (Anything other than MoveTo) followed by (LineTo the same place) is a nop */
	if (LAST_CMD(path) != FZ_MOVETO && x0 == x && y0 == y)
		return;

	if (x0 == x)
	{
		if (y0 == y)
		{
			if (LAST_CMD(path) != FZ_MOVETO)
				return;
			push_cmd(ctx, path, FZ_DEGENLINETO);
		}
		else
		{
			push_cmd(ctx, path, FZ_VERTTO);
			push_ord(ctx, path, y, 0);
		}
	}
	else if (y0 == y)
	{
		push_cmd(ctx, path, FZ_HORIZTO);
		push_ord(ctx, path, x, 1);
	}
	else
	{
		push_cmd(ctx, path, FZ_LINETO);
		push_coord(ctx, path, x, y);
	}
}

void
fz_curveto(fz_context *ctx, fz_path *path,
	float x1, float y1,
	float x2, float y2,
	float x3, float y3)
{
	float x0, y0;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	x0 = path->current.x;
	y0 = path->current.y;

	if (path->cmd_len == 0)
	{
		fz_warn(ctx, "curveto with no current point");
		return;
	}

	/* Check for degenerate cases: */
	if (x0 == x1 && y0 == y1)
	{
		if (x2 == x3 && y2 == y3)
		{
			/* If (x1,y1)==(x2,y2) and prev wasn't a moveto, then skip */
			if (x1 == x2 && y1 == y2 && LAST_CMD(path) != FZ_MOVETO)
				return;
			/* Otherwise a line will suffice */
			fz_lineto(ctx, path, x3, y3);
		}
		else if (x1 == x2 && y1 == y2)
		{
			/* A line will suffice */
			fz_lineto(ctx, path, x3, y3);
		}
		else
			fz_curvetov(ctx, path, x2, y2, x3, y3);
		return;
	}
	else if (x2 == x3 && y2 == y3)
	{
		if (x1 == x2 && y1 == y2)
		{
			/* A line will suffice */
			fz_lineto(ctx, path, x3, y3);
		}
		else
			fz_curvetoy(ctx, path, x1, y1, x3, y3);
		return;
	}

	push_cmd(ctx, path, FZ_CURVETO);
	push_coord(ctx, path, x1, y1);
	push_coord(ctx, path, x2, y2);
	push_coord(ctx, path, x3, y3);
}

void
fz_quadto(fz_context *ctx, fz_path *path,
	float x1, float y1,
	float x2, float y2)
{
	float x0, y0;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	x0 = path->current.x;
	y0 = path->current.y;

	if (path->cmd_len == 0)
	{
		fz_warn(ctx, "quadto with no current point");
		return;
	}

	/* Check for degenerate cases: */
	if ((x0 == x1 && y0 == y1) || (x1 == x2 && y1 == y2))
	{
		if (x0 == x2 && y0 == y2 && LAST_CMD(path) != FZ_MOVETO)
			return;
		/* A line will suffice */
		fz_lineto(ctx, path, x2, y2);
		return;
	}

	push_cmd(ctx, path, FZ_QUADTO);
	push_coord(ctx, path, x1, y1);
	push_coord(ctx, path, x2, y2);
}

void
fz_curvetov(fz_context *ctx, fz_path *path, float x2, float y2, float x3, float y3)
{
	float x0, y0;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	x0 = path->current.x;
	y0 = path->current.y;

	if (path->cmd_len == 0)
	{
		fz_warn(ctx, "curveto with no current point");
		return;
	}

	/* Check for degenerate cases: */
	if (x2 == x3 && y2 == y3)
	{
		/* If (x0,y0)==(x2,y2) and prev wasn't a moveto, then skip */
		if (x0 == x2 && y0 == y2 && LAST_CMD(path) != FZ_MOVETO)
			return;
		/* Otherwise a line will suffice */
		fz_lineto(ctx, path, x3, y3);
	}
	else if (x0 == x2 && y0 == y2)
	{
		/* A line will suffice */
		fz_lineto(ctx, path, x3, y3);
	}

	push_cmd(ctx, path, FZ_CURVETOV);
	push_coord(ctx, path, x2, y2);
	push_coord(ctx, path, x3, y3);
}

void
fz_curvetoy(fz_context *ctx, fz_path *path, float x1, float y1, float x3, float y3)
{
	float x0, y0;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	x0 = path->current.x;
	y0 = path->current.y;

	if (path->cmd_len == 0)
	{
		fz_warn(ctx, "curveto with no current point");
		return;
	}

	/* Check for degenerate cases: */
	if (x1 == x3 && y1 == y3)
	{
		/* If (x0,y0)==(x1,y1) and prev wasn't a moveto, then skip */
		if (x0 == x1 && y0 == y1 && LAST_CMD(path) != FZ_MOVETO)
			return;
		/* Otherwise a line will suffice */
		fz_lineto(ctx, path, x3, y3);
	}

	push_cmd(ctx, path, FZ_CURVETOY);
	push_coord(ctx, path, x1, y1);
	push_coord(ctx, path, x3, y3);
}

void
fz_closepath(fz_context *ctx, fz_path *path)
{
	uint8_t rep;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	if (path->cmd_len == 0)
	{
		fz_warn(ctx, "closepath with no current point");
		return;
	}

	switch(LAST_CMD(path))
	{
	case FZ_MOVETO:
		rep = FZ_MOVETOCLOSE;
		break;
	case FZ_LINETO:
		rep = FZ_LINETOCLOSE;
		break;
	case FZ_DEGENLINETO:
		rep = FZ_DEGENLINETOCLOSE;
		break;
	case FZ_CURVETO:
		rep = FZ_CURVETOCLOSE;
		break;
	case FZ_CURVETOV:
		rep = FZ_CURVETOVCLOSE;
		break;
	case FZ_CURVETOY:
		rep = FZ_CURVETOYCLOSE;
		break;
	case FZ_HORIZTO:
		rep = FZ_HORIZTOCLOSE;
		break;
	case FZ_VERTTO:
		rep = FZ_VERTTOCLOSE;
		break;
	case FZ_QUADTO:
		rep = FZ_QUADTOCLOSE;
		break;
	case FZ_RECTTO:
		/* RectTo implies close */
		return;
	case FZ_MOVETOCLOSE:
	case FZ_LINETOCLOSE:
	case FZ_DEGENLINETOCLOSE:
	case FZ_CURVETOCLOSE:
	case FZ_CURVETOVCLOSE:
	case FZ_CURVETOYCLOSE:
	case FZ_HORIZTOCLOSE:
	case FZ_VERTTOCLOSE:
	case FZ_QUADTOCLOSE:
		/* CLOSE following a CLOSE is a NOP */
		return;
	default: /* default never happens */
	case 0:
		/* Closing an empty path is a NOP */
		return;
	}

	path->cmds[path->cmd_len-1] = rep;

	path->current = path->begin;
}

void
fz_rectto(fz_context *ctx, fz_path *path, float x1, float y1, float x2, float y2)
{
	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot modify a packed path");

	if (path->cmd_len > 0 && LAST_CMD(path) == FZ_MOVETO)
	{
		/* Collapse moveto followed by rectto. */
		path->coord_len -= 2;
		path->cmd_len--;
	}

	push_cmd(ctx, path, FZ_RECTTO);
	push_coord(ctx, path, x1, y1);
	push_coord(ctx, path, x2, y2);

	path->current = path->begin;
}

static inline void bound_expand(fz_rect *r, fz_point p)
{
	if (p.x < r->x0) r->x0 = p.x;
	if (p.y < r->y0) r->y0 = p.y;
	if (p.x > r->x1) r->x1 = p.x;
	if (p.y > r->y1) r->y1 = p.y;
}

void fz_walk_path(fz_context *ctx, const fz_path *path, const fz_path_walker *proc, void *arg)
{
	int i, k, cmd_len;
	float x, y, sx, sy;
	uint8_t *cmds;
	float *coords;

	switch (path->packed)
	{
	case FZ_PATH_UNPACKED:
	case FZ_PATH_PACKED_OPEN:
		cmd_len = path->cmd_len;
		coords = path->coords;
		cmds = path->cmds;
		break;
	case FZ_PATH_PACKED_FLAT:
		cmd_len = ((fz_packed_path *)path)->cmd_len;
		coords = (float *)&((fz_packed_path *)path)[1];
		cmds = (uint8_t *)&coords[((fz_packed_path *)path)->coord_len];
		break;
	default:
		assert("This never happens" == NULL);
		return;
	}

	if (cmd_len == 0)
		return;

	for (k=0, i = 0; i < cmd_len; i++)
	{
		uint8_t cmd = cmds[i];

		switch (cmd)
		{
		case FZ_CURVETO:
		case FZ_CURVETOCLOSE:
			proc->curveto(ctx, arg,
					coords[k],
					coords[k+1],
					coords[k+2],
					coords[k+3],
					x = coords[k+4],
					y = coords[k+5]);
			k += 6;
			if (cmd == FZ_CURVETOCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_CURVETOV:
		case FZ_CURVETOVCLOSE:
			if (proc->curvetov)
				proc->curvetov(ctx, arg,
						coords[k],
						coords[k+1],
						x = coords[k+2],
						y = coords[k+3]);
			else
			{
				proc->curveto(ctx, arg,
						x,
						y,
						coords[k],
						coords[k+1],
						coords[k+2],
						coords[k+3]);
				x = coords[k+2];
				y = coords[k+3];
			}
			k += 4;
			if (cmd == FZ_CURVETOVCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_CURVETOY:
		case FZ_CURVETOYCLOSE:
			if (proc->curvetoy)
				proc->curvetoy(ctx, arg,
						coords[k],
						coords[k+1],
						x = coords[k+2],
						y = coords[k+3]);
			else
				proc->curveto(ctx, arg,
						coords[k],
						coords[k+1],
						coords[k+2],
						coords[k+3],
						x = coords[k+2],
						y = coords[k+3]);
			k += 4;
			if (cmd == FZ_CURVETOYCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_QUADTO:
		case FZ_QUADTOCLOSE:
			if (proc->quadto)
				proc->quadto(ctx, arg,
					coords[k],
					coords[k+1],
					x = coords[k+2],
					y = coords[k+3]);
			else
			{
				float c2x = coords[k] * 2;
				float c2y = coords[k+1] * 2;
				float c1x = (x + c2x) / 3;
				float c1y = (y + c2y) / 3;
				x = coords[k+2];
				y = coords[k+3];
				c2x = (c2x + x) / 3;
				c2y = (c2y + y) / 3;

				proc->curveto(ctx, arg,
					c1x,
					c1y,
					c2x,
					c2y,
					x,
					y);
			}
			k += 4;
			if (cmd == FZ_QUADTOCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_MOVETO:
		case FZ_MOVETOCLOSE:
			proc->moveto(ctx, arg,
				x = coords[k],
				y = coords[k+1]);
			k += 2;
			sx = x;
			sy = y;
			if (cmd == FZ_MOVETOCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_LINETO:
		case FZ_LINETOCLOSE:
			proc->lineto(ctx, arg,
				x = coords[k],
				y = coords[k+1]);
			k += 2;
			if (cmd == FZ_LINETOCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_HORIZTO:
		case FZ_HORIZTOCLOSE:
			proc->lineto(ctx, arg,
				x = coords[k],
				y);
			k += 1;
			if (cmd == FZ_HORIZTOCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_VERTTO:
		case FZ_VERTTOCLOSE:
			proc->lineto(ctx, arg,
				x,
				y = coords[k]);
			k += 1;
			if (cmd == FZ_VERTTOCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_DEGENLINETO:
		case FZ_DEGENLINETOCLOSE:
			proc->lineto(ctx, arg,
				x,
				y);
			if (cmd == FZ_DEGENLINETOCLOSE)
			{
				if (proc->closepath)
					proc->closepath(ctx, arg);
				x = sx;
				y = sy;
			}
			break;
		case FZ_RECTTO:
			if (proc->rectto)
			{
				proc->rectto(ctx, arg,
						x = coords[k],
						y = coords[k+1],
						coords[k+2],
						coords[k+3]);
			}
			else
			{
				proc->moveto(ctx, arg,
					x = coords[k],
					y = coords[k+1]);
				proc->lineto(ctx, arg,
					coords[k+2],
					coords[k+1]);
				proc->lineto(ctx, arg,
					coords[k+2],
					coords[k+3]);
				proc->lineto(ctx, arg,
					coords[k],
					coords[k+3]);
				if (proc->closepath)
					proc->closepath(ctx, arg);
			}
			sx = x;
			sy = y;
			k += 4;
			break;
		}
	}
}

typedef struct
{
	fz_matrix ctm;
	fz_rect rect;
	fz_point move;
	int trailing_move;
	int first;
} bound_path_arg;

static void
bound_moveto(fz_context *ctx, void *arg_, float x, float y)
{
	bound_path_arg *arg = (bound_path_arg *)arg_;
	arg->move = fz_transform_point_xy(x, y, arg->ctm);
	arg->trailing_move = 1;
}

static void
bound_lineto(fz_context *ctx, void *arg_, float x, float y)
{
	bound_path_arg *arg = (bound_path_arg *)arg_;
	fz_point p = fz_transform_point_xy(x, y, arg->ctm);
	if (arg->first)
	{
		arg->rect.x0 = arg->rect.x1 = p.x;
		arg->rect.y0 = arg->rect.y1 = p.y;
		arg->first = 0;
	}
	else
		bound_expand(&arg->rect, p);
	if (arg->trailing_move)
	{
		arg->trailing_move = 0;
		bound_expand(&arg->rect, arg->move);
	}
}

static void
bound_curveto(fz_context *ctx, void *arg_, float x1, float y1, float x2, float y2, float x3, float y3)
{
	bound_path_arg *arg = (bound_path_arg *)arg_;
	fz_point p = fz_transform_point_xy(x1, y1, arg->ctm);
	if (arg->first)
	{
		arg->rect.x0 = arg->rect.x1 = p.x;
		arg->rect.y0 = arg->rect.y1 = p.y;
		arg->first = 0;
	}
	else
		bound_expand(&arg->rect, p);
	bound_expand(&arg->rect, fz_transform_point_xy(x2, y2, arg->ctm));
	bound_expand(&arg->rect, fz_transform_point_xy(x3, y3, arg->ctm));
	if (arg->trailing_move)
	{
		arg->trailing_move = 0;
		bound_expand(&arg->rect, arg->move);
	}
}

static const fz_path_walker bound_path_walker =
{
	bound_moveto,
	bound_lineto,
	bound_curveto,
	NULL
};

fz_rect
fz_bound_path(fz_context *ctx, const fz_path *path, const fz_stroke_state *stroke, fz_matrix ctm)
{
	bound_path_arg arg;

	arg.ctm = ctm;
	arg.rect = fz_empty_rect;
	arg.trailing_move = 0;
	arg.first = 1;

	fz_walk_path(ctx, path, &bound_path_walker, &arg);

	if (!arg.first && stroke)
	{
		arg.rect = fz_adjust_rect_for_stroke(ctx, arg.rect, stroke, ctm);
	}

	return arg.rect;
}

fz_rect
fz_adjust_rect_for_stroke(fz_context *ctx, fz_rect r, const fz_stroke_state *stroke, fz_matrix ctm)
{
	float expand;

	if (!stroke)
		return r;

	expand = stroke->linewidth;
	if (expand == 0)
		expand = 1.0f;
	expand *= fz_matrix_max_expansion(ctm);
	if ((stroke->linejoin == FZ_LINEJOIN_MITER || stroke->linejoin == FZ_LINEJOIN_MITER_XPS) && stroke->miterlimit > 1)
		expand *= stroke->miterlimit;

	r.x0 -= expand;
	r.y0 -= expand;
	r.x1 += expand;
	r.y1 += expand;
	return r;
}

void
fz_transform_path(fz_context *ctx, fz_path *path, fz_matrix ctm)
{
	int i, k, n;
	fz_point p, p1, p2, p3, q, s;

	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Cannot transform a packed path");

	if (ctm.b == 0 && ctm.c == 0)
	{
		/* Simple, in place transform */
		i = 0;
		k = 0;
		while (i < path->cmd_len)
		{
			uint8_t cmd = path->cmds[i];

			switch (cmd)
			{
			case FZ_MOVETO:
			case FZ_LINETO:
			case FZ_MOVETOCLOSE:
			case FZ_LINETOCLOSE:
				n = 1;
				break;
			case FZ_DEGENLINETO:
			case FZ_DEGENLINETOCLOSE:
				n = 0;
				break;
			case FZ_CURVETO:
			case FZ_CURVETOCLOSE:
				n = 3;
				break;
			case FZ_RECTTO:
				s.x = path->coords[k];
				s.y = path->coords[k+1];
				n = 2;
				break;
			case FZ_CURVETOV:
			case FZ_CURVETOY:
			case FZ_QUADTO:
			case FZ_CURVETOVCLOSE:
			case FZ_CURVETOYCLOSE:
			case FZ_QUADTOCLOSE:
				n = 2;
				break;
			case FZ_HORIZTO:
			case FZ_HORIZTOCLOSE:
				q.x = path->coords[k];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.x;
				n = 0;
				break;
			case FZ_VERTTO:
			case FZ_VERTTOCLOSE:
				q.y = path->coords[k];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.y;
				n = 0;
				break;
			default:
				assert("Unknown path cmd" == NULL);
			}
			while (n > 0)
			{
				q.x = path->coords[k];
				q.y = path->coords[k+1];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.x;
				path->coords[k++] = p.y;
				n--;
			}
			switch (cmd)
			{
			case FZ_MOVETO:
			case FZ_MOVETOCLOSE:
				s = q;
				break;
			case FZ_LINETOCLOSE:
			case FZ_DEGENLINETOCLOSE:
			case FZ_CURVETOCLOSE:
			case FZ_CURVETOVCLOSE:
			case FZ_CURVETOYCLOSE:
			case FZ_QUADTOCLOSE:
			case FZ_HORIZTOCLOSE:
			case FZ_VERTTOCLOSE:
			case FZ_RECTTO:
				q = s;
				break;
			}
			i++;
		}
	}
	else if (ctm.a == 0 && ctm.d == 0)
	{
		/* In place transform with command rewriting */
		i = 0;
		k = 0;
		while (i < path->cmd_len)
		{
			uint8_t cmd = path->cmds[i];

			switch (cmd)
			{
			case FZ_MOVETO:
			case FZ_LINETO:
			case FZ_MOVETOCLOSE:
			case FZ_LINETOCLOSE:
				n = 1;
				break;
			case FZ_DEGENLINETO:
			case FZ_DEGENLINETOCLOSE:
				n = 0;
				break;
			case FZ_CURVETO:
			case FZ_CURVETOCLOSE:
				n = 3;
				break;
			case FZ_RECTTO:
				s.x = path->coords[k];
				s.y = path->coords[k+1];
				n = 2;
				break;
			case FZ_CURVETOV:
			case FZ_CURVETOY:
			case FZ_QUADTO:
			case FZ_CURVETOVCLOSE:
			case FZ_CURVETOYCLOSE:
			case FZ_QUADTOCLOSE:
				n = 2;
				break;
			case FZ_HORIZTO:
				q.x = path->coords[k];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.y;
				path->cmds[i] = FZ_VERTTO;
				n = 0;
				break;
			case FZ_HORIZTOCLOSE:
				q.x = path->coords[k];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.y;
				path->cmds[i] = FZ_VERTTOCLOSE;
				n = 0;
				break;
			case FZ_VERTTO:
				q.y = path->coords[k];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.x;
				path->cmds[i] = FZ_HORIZTO;
				n = 0;
				break;
			case FZ_VERTTOCLOSE:
				q.y = path->coords[k];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.x;
				path->cmds[i] = FZ_HORIZTOCLOSE;
				n = 0;
				break;
			default:
				assert("Unknown path cmd" == NULL);
			}
			while (n > 0)
			{
				q.x = path->coords[k];
				q.y = path->coords[k+1];
				p = fz_transform_point(q, ctm);
				path->coords[k++] = p.x;
				path->coords[k++] = p.y;
				n--;
			}
			switch (cmd)
			{
			case FZ_MOVETO:
			case FZ_MOVETOCLOSE:
				s = q;
				break;
			case FZ_LINETOCLOSE:
			case FZ_DEGENLINETOCLOSE:
			case FZ_CURVETOCLOSE:
			case FZ_CURVETOVCLOSE:
			case FZ_CURVETOYCLOSE:
			case FZ_QUADTOCLOSE:
			case FZ_HORIZTOCLOSE:
			case FZ_VERTTOCLOSE:
			case FZ_RECTTO:
				q = s;
				break;
			}
			i++;
		}
	}
	else
	{
		int extra_coord = 0;
		int extra_cmd = 0;
		int coord_read, coord_write, cmd_read, cmd_write;

		/* General case. Have to allow for rects/horiz/verts
		 * becoming non-rects/horiz/verts. */
		for (i = 0; i < path->cmd_len; i++)
		{
			uint8_t cmd = path->cmds[i];
			switch (cmd)
			{
			case FZ_HORIZTO:
			case FZ_VERTTO:
			case FZ_HORIZTOCLOSE:
			case FZ_VERTTOCLOSE:
				extra_coord += 1;
				break;
			case FZ_RECTTO:
				extra_coord += 2;
				extra_cmd += 3;
				break;
			default:
				/* Do nothing */
				break;
			}
		}
		if (path->cmd_len + extra_cmd < path->cmd_cap)
		{
			path->cmds = fz_resize_array(ctx, path->cmds, path->cmd_len + extra_cmd, sizeof(unsigned char));
			path->cmd_cap = path->cmd_len + extra_cmd;
		}
		if (path->coord_len + extra_coord < path->coord_cap)
		{
			path->coords = fz_resize_array(ctx, path->coords, path->coord_len + extra_coord, sizeof(float));
			path->coord_cap = path->coord_len + extra_coord;
		}
		memmove(path->cmds + extra_cmd, path->cmds, path->cmd_len * sizeof(unsigned char));
		path->cmd_len += extra_cmd;
		memmove(path->coords + extra_coord, path->coords, path->coord_len * sizeof(float));
		path->coord_len += extra_coord;

		for (cmd_write = 0, cmd_read = extra_cmd, coord_write = 0, coord_read = extra_coord; cmd_read < path->cmd_len; i += 2)
		{
			uint8_t cmd = path->cmds[cmd_write++] = path->cmds[cmd_read++];

			switch (cmd)
			{
			case FZ_MOVETO:
			case FZ_LINETO:
			case FZ_MOVETOCLOSE:
			case FZ_LINETOCLOSE:
				n = 1;
				break;
			case FZ_DEGENLINETO:
			case FZ_DEGENLINETOCLOSE:
				n = 0;
				break;
			case FZ_CURVETO:
			case FZ_CURVETOCLOSE:
				n = 3;
				break;
			case FZ_CURVETOV:
			case FZ_CURVETOY:
			case FZ_QUADTO:
			case FZ_CURVETOVCLOSE:
			case FZ_CURVETOYCLOSE:
			case FZ_QUADTOCLOSE:
				n = 2;
				break;
			case FZ_RECTTO:
				p.x = path->coords[coord_read++];
				p.y = path->coords[coord_read++];
				p2.x = path->coords[coord_read++];
				p2.y = path->coords[coord_read++];
				p1.x = p2.x;
				p1.y = p.y;
				p3.x = p.x;
				p3.y = p2.y;
				s = p;
				p = fz_transform_point(p, ctm);
				p1 = fz_transform_point(p1, ctm);
				p2 = fz_transform_point(p2, ctm);
				p3 = fz_transform_point(p3, ctm);
				path->coords[coord_write++] = p.x;
				path->coords[coord_write++] = p.y;
				path->coords[coord_write++] = p1.x;
				path->coords[coord_write++] = p1.y;
				path->coords[coord_write++] = p2.x;
				path->coords[coord_write++] = p2.y;
				path->coords[coord_write++] = p3.x;
				path->coords[coord_write++] = p3.y;
				path->cmds[cmd_write-1] = FZ_MOVETO;
				path->cmds[cmd_write++] = FZ_LINETO;
				path->cmds[cmd_write++] = FZ_LINETO;
				path->cmds[cmd_write++] = FZ_LINETOCLOSE;
				n = 0;
				break;
			case FZ_HORIZTO:
				q.x = path->coords[coord_read++];
				p = fz_transform_point(q, ctm);
				path->coords[coord_write++] = p.x;
				path->coords[coord_write++] = p.y;
				path->cmds[cmd_write-1] = FZ_LINETO;
				n = 0;
				break;
			case FZ_HORIZTOCLOSE:
				p.x = path->coords[coord_read++];
				p.y = q.y;
				p = fz_transform_point(p, ctm);
				path->coords[coord_write++] = p.x;
				path->coords[coord_write++] = p.y;
				path->cmds[cmd_write-1] = FZ_LINETOCLOSE;
				q = s;
				n = 0;
				break;
			case FZ_VERTTO:
				q.y = path->coords[coord_read++];
				p = fz_transform_point(q, ctm);
				path->coords[coord_write++] = p.x;
				path->coords[coord_write++] = p.y;
				path->cmds[cmd_write-1] = FZ_LINETO;
				n = 0;
				break;
			case FZ_VERTTOCLOSE:
				p.x = q.x;
				p.y = path->coords[coord_read++];
				p = fz_transform_point(p, ctm);
				path->coords[coord_write++] = p.x;
				path->coords[coord_write++] = p.y;
				path->cmds[cmd_write-1] = FZ_LINETOCLOSE;
				q = s;
				n = 0;
				break;
			default:
				assert("Unknown path cmd" == NULL);
			}
			while (n > 0)
			{
				q.x = path->coords[coord_read++];
				q.y = path->coords[coord_read++];
				p = fz_transform_point(q, ctm);
				path->coords[coord_write++] = p.x;
				path->coords[coord_write++] = p.y;
				n--;
			}
			switch (cmd)
			{
			case FZ_MOVETO:
			case FZ_MOVETOCLOSE:
				s = q;
				break;
			case FZ_LINETOCLOSE:
			case FZ_DEGENLINETOCLOSE:
			case FZ_CURVETOCLOSE:
			case FZ_CURVETOYCLOSE:
			case FZ_CURVETOVCLOSE:
			case FZ_QUADTOCLOSE:
			case FZ_HORIZTOCLOSE:
			case FZ_VERTTOCLOSE:
			case FZ_RECTTO:
				q = s;
				break;
			}
		}
	}
}

void fz_trim_path(fz_context *ctx, fz_path *path)
{
	if (path->packed)
		fz_throw(ctx, FZ_ERROR_GENERIC, "Can't trim a packed path");
	if (path->cmd_cap > path->cmd_len)
	{
		path->cmds = fz_resize_array(ctx, path->cmds, path->cmd_len, sizeof(unsigned char));
		path->cmd_cap = path->cmd_len;
	}
	if (path->coord_cap > path->coord_len)
	{
		path->coords = fz_resize_array(ctx, path->coords, path->coord_len, sizeof(float));
		path->coord_cap = path->coord_len;
	}
}

const fz_stroke_state fz_default_stroke_state = {
	-2, /* -2 is the magic number we use when we have stroke states stored on the stack */
	FZ_LINECAP_BUTT, FZ_LINECAP_BUTT, FZ_LINECAP_BUTT,
	FZ_LINEJOIN_MITER,
	1, 10,
	0, 0, { 0 }
};

fz_stroke_state *
fz_keep_stroke_state(fz_context *ctx, const fz_stroke_state *strokec)
{
	fz_stroke_state *stroke = (fz_stroke_state *)strokec; /* Explicit cast away of const */

	if (!stroke)
		return NULL;

	/* -2 is the magic number we use when we have stroke states stored on the stack */
	if (stroke->refs == -2)
		return fz_clone_stroke_state(ctx, stroke);

	return fz_keep_imp(ctx, stroke, &stroke->refs);
}

void
fz_drop_stroke_state(fz_context *ctx, const fz_stroke_state *strokec)
{
	fz_stroke_state *stroke = (fz_stroke_state *)strokec; /* Explicit cast away of const */

	if (fz_drop_imp(ctx, stroke, &stroke->refs))
		fz_free(ctx, stroke);
}

fz_stroke_state *
fz_new_stroke_state_with_dash_len(fz_context *ctx, int len)
{
	fz_stroke_state *state;

	len -= nelem(state->dash_list);
	if (len < 0)
		len = 0;

	state = Memento_label(fz_malloc(ctx, sizeof(*state) + sizeof(state->dash_list[0]) * len), "fz_stroke_state");
	state->refs = 1;
	state->start_cap = FZ_LINECAP_BUTT;
	state->dash_cap = FZ_LINECAP_BUTT;
	state->end_cap = FZ_LINECAP_BUTT;
	state->linejoin = FZ_LINEJOIN_MITER;
	state->linewidth = 1;
	state->miterlimit = 10;
	state->dash_phase = 0;
	state->dash_len = 0;
	memset(state->dash_list, 0, sizeof(state->dash_list[0]) * (len + nelem(state->dash_list)));

	return state;
}

fz_stroke_state *
fz_new_stroke_state(fz_context *ctx)
{
	return fz_new_stroke_state_with_dash_len(ctx, 0);
}

fz_stroke_state *
fz_clone_stroke_state(fz_context *ctx, fz_stroke_state *stroke)
{
	fz_stroke_state *clone = fz_new_stroke_state_with_dash_len(ctx, stroke->dash_len);
	int extra = stroke->dash_len - nelem(stroke->dash_list);
	int size = sizeof(*stroke) + sizeof(stroke->dash_list[0]) * extra;
	memcpy(clone, stroke, size);
	clone->refs = 1;
	return clone;
}

fz_stroke_state *
fz_unshare_stroke_state_with_dash_len(fz_context *ctx, fz_stroke_state *shared, int len)
{
	int single, unsize, shsize, shlen;
	fz_stroke_state *unshared;

	fz_lock(ctx, FZ_LOCK_ALLOC);
	single = (shared->refs == 1);
	fz_unlock(ctx, FZ_LOCK_ALLOC);

	shlen = shared->dash_len - nelem(shared->dash_list);
	if (shlen < 0)
		shlen = 0;
	shsize = sizeof(*shared) + sizeof(shared->dash_list[0]) * shlen;
	len -= nelem(shared->dash_list);
	if (len < 0)
		len = 0;
	if (single && shlen >= len)
		return shared;

	unsize = sizeof(*unshared) + sizeof(unshared->dash_list[0]) * len;
	unshared = Memento_label(fz_malloc(ctx, unsize), "fz_stroke_state");
	memcpy(unshared, shared, (shsize > unsize ? unsize : shsize));
	unshared->refs = 1;

	if (fz_drop_imp(ctx, shared, &shared->refs))
		fz_free(ctx, shared);
	return unshared;
}

fz_stroke_state *
fz_unshare_stroke_state(fz_context *ctx, fz_stroke_state *shared)
{
	return fz_unshare_stroke_state_with_dash_len(ctx, shared, shared->dash_len);
}

static void *
clone_block(fz_context *ctx, void *block, size_t len)
{
	void *target;

	if (len == 0 || block == NULL)
		return NULL;

	target = fz_malloc(ctx, len);
	memcpy(target, block, len);
	return target;
}

fz_path *
fz_clone_path(fz_context *ctx, fz_path *path)
{
	fz_path *new_path;

	assert(ctx != NULL);

	if (path == NULL)
		return NULL;

	new_path = fz_malloc_struct(ctx, fz_path);
	new_path->refs = 1;
	new_path->packed = FZ_PATH_UNPACKED;
	fz_try(ctx)
	{
		switch(path->packed)
		{
		case FZ_PATH_UNPACKED:
		case FZ_PATH_PACKED_OPEN:
			new_path->cmd_len = path->cmd_len;
			new_path->cmd_cap = path->cmd_cap;
			new_path->cmds = clone_block(ctx, path->cmds, path->cmd_cap);
			new_path->coord_len = path->coord_len;
			new_path->coord_cap = path->coord_cap;
			new_path->coords = clone_block(ctx, path->coords, sizeof(float)*path->coord_cap);
			new_path->current = path->current;
			new_path->begin = path->begin;
			break;
		case FZ_PATH_PACKED_FLAT:
			{
				uint8_t *data;
				float *xy;
				int i;
				fz_packed_path *ppath = (fz_packed_path *)path;

				new_path->cmd_len = ppath->cmd_len;
				new_path->cmd_cap = ppath->cmd_len;
				new_path->coord_len = ppath->coord_len;
				new_path->coord_cap = ppath->coord_len;
				data = (uint8_t *)&ppath[1];
				new_path->coords = clone_block(ctx, data, sizeof(float)*path->coord_cap);
				data += sizeof(float) * path->coord_cap;
				new_path->cmds = clone_block(ctx, data, path->cmd_cap);
				xy = new_path->coords;
				for (i = 0; i < new_path->cmd_len; i++)
				{
					switch (new_path->cmds[i])
					{
					case FZ_MOVETOCLOSE:
					case FZ_MOVETO:
						new_path->current.x = *xy++;
						new_path->current.y = *xy++;
						new_path->begin.x = new_path->current.x;
						new_path->begin.y = new_path->current.y;
						break;
					case FZ_CURVETO:
						xy += 2;
						/* fallthrough */
					case FZ_CURVETOV:
					case FZ_CURVETOY:
					case FZ_QUADTO:
						/* fallthrough */
						xy += 2;
					case FZ_LINETO:
						new_path->current.x = *xy++;
						new_path->current.y = *xy++;
						break;
					case FZ_DEGENLINETO:
						break;
					case FZ_HORIZTO:
						new_path->current.x = *xy++;
						break;
					case FZ_VERTTO:
						new_path->current.y = *xy++;
						break;
					case FZ_RECTTO:
						xy += 2;
						break;
					case FZ_CURVETOCLOSE:
						xy += 2;
						/* fallthrough */
					case FZ_CURVETOVCLOSE:
					case FZ_CURVETOYCLOSE:
					case FZ_QUADTOCLOSE:
					case FZ_LINETOCLOSE:
						xy++;
						/* fallthrough */
					case FZ_HORIZTOCLOSE:
					case FZ_VERTTOCLOSE:
						xy++;
						/* fallthrough */
					case FZ_DEGENLINETOCLOSE:
						new_path->current.x = new_path->begin.x;
						new_path->current.y = new_path->begin.y;
						break;
					}
				}
			}
		default:
			fz_throw(ctx, FZ_ERROR_GENERIC, "Unknown packing method found in path");
		}
	}
	fz_catch(ctx)
	{
		fz_free(ctx, new_path->coords);
		fz_free(ctx, new_path->cmds);
		fz_free(ctx, new_path);
		fz_rethrow(ctx);
	}
	return new_path;
}