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1
#include "mupdf/fitz.h"

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#include <jbig2.h>

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typedef struct fz_jbig2d_s fz_jbig2d;

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struct fz_jbig2_globals_s

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{

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	fz_storable storable;

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	Jbig2GlobalCtx *gctx;

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};

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struct fz_jbig2d_s

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{

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	fz_stream *chain;

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	Jbig2Ctx *ctx;

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	fz_jbig2_globals *gctx;

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	Jbig2Image *page;

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	int idx;

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	unsigned char buffer[4096];

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};

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static void

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fz_drop_jbig2_globals(fz_context *ctx, fz_jbig2_globals *globals)

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{

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	fz_drop_storable(ctx, &globals->storable);

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}

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static void

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close_jbig2d(fz_context *ctx, void *state_)

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{

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	fz_jbig2d *state = (fz_jbig2d *)state_;

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	if (state->page)

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		jbig2_release_page(state->ctx, state->page);

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	if (state->gctx)

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		fz_drop_jbig2_globals(ctx, state->gctx);

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	jbig2_ctx_free(state->ctx);

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	fz_drop_stream(ctx, state->chain);

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	fz_free(ctx, state);

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}

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static int

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next_jbig2d(fz_context *ctx, fz_stream *stm, int len)

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{

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	fz_jbig2d *state = stm->state;

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	unsigned char tmp[4096];

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	unsigned char *buf = state->buffer;

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	unsigned char *p = buf;

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	unsigned char *ep;

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	unsigned char *s;

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	int x, w, n;

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	if (len > sizeof(state->buffer))

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		len = sizeof(state->buffer);

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	ep = buf + len;

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	if (!state->page)

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	{

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		while (1)

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		{

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			n = fz_read(ctx, state->chain, tmp, sizeof tmp);

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			if (n == 0)

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				break;

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			jbig2_data_in(state->ctx, tmp, n);

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		}

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		jbig2_complete_page(state->ctx);

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		state->page = jbig2_page_out(state->ctx);

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		if (!state->page)

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			fz_throw(ctx, FZ_ERROR_GENERIC, "jbig2_page_out failed");

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	}

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	s = state->page->data;

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	w = state->page->height * state->page->stride;

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	x = state->idx;

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	while (p < ep && x < w)

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		*p++ = s[x++] ^ 0xff;

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	state->idx = x;

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	stm->rp = buf;

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	stm->wp = p;

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	if (p == buf)

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		return EOF;

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	stm->pos += p - buf;

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	return *stm->rp++;

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}

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static int

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error_callback(void *data, const char *msg, Jbig2Severity severity, int32_t seg_idx)

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{

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	fz_context *ctx = data;

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	if (severity == JBIG2_SEVERITY_FATAL)

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		fz_warn(ctx, "jbig2dec error: %s (segment %d)", msg, seg_idx);

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	else if (severity == JBIG2_SEVERITY_WARNING)

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		fz_warn(ctx, "jbig2dec warning: %s (segment %d)", msg, seg_idx);

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	return 0;

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}

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fz_jbig2_globals *

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fz_load_jbig2_globals(fz_context *ctx, unsigned char *data, int size)

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{

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	fz_jbig2_globals *globals = fz_malloc_struct(ctx, fz_jbig2_globals);

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	Jbig2Ctx *jctx = jbig2_ctx_new(NULL, JBIG2_OPTIONS_EMBEDDED, NULL, error_callback, ctx);

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	jbig2_data_in(jctx, data, size);

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	FZ_INIT_STORABLE(globals, 1, fz_drop_jbig2_globals_imp);

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	globals->gctx = jbig2_make_global_ctx(jctx);

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	return globals;

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}

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void

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fz_drop_jbig2_globals_imp(fz_context *ctx, fz_storable *globals_)

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{

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	fz_jbig2_globals *globals = (fz_jbig2_globals *)globals_;

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	jbig2_global_ctx_free(globals->gctx);

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	fz_free(ctx, globals);

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}

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fz_stream *

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fz_open_jbig2d(fz_context *ctx, fz_stream *chain, fz_jbig2_globals *globals)

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{

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	fz_jbig2d *state = NULL;

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	fz_var(state);

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	fz_try(ctx)

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	{

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		state = fz_malloc_struct(ctx, fz_jbig2d);

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		state->ctx = NULL;

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		state->gctx = globals;

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		state->chain = chain;

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		state->ctx = jbig2_ctx_new(NULL, JBIG2_OPTIONS_EMBEDDED, globals ? globals->gctx : NULL, error_callback, ctx);

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		state->page = NULL;

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		state->idx = 0;

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	}

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	fz_catch(ctx)

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	{

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		if (state)

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		{

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			fz_drop_jbig2_globals(ctx, state->gctx);

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			if (state->ctx)

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				jbig2_ctx_free(state->ctx);

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		}

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		fz_free(ctx, state);

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		fz_drop_stream(ctx, chain);

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		fz_rethrow(ctx);

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	}

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	return fz_new_stream(ctx, state, next_jbig2d, close_jbig2d);

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}

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