Avoid deadlocks

[llpp.git] / link.c

/* lots of code c&p-ed directly from mupdf */
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define PIGGYBACK

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#define fionread_arg long
#define ssize_t int
#define FMT_ss "d"
#ifdef _WIN64
#define FMT_s "i64u"
#else
#define FMT_s "u"
#endif
#endif

#ifdef _MSC_VER
#pragma warning (disable:4244)
#pragma warning (disable:4996)
#pragma warning (disable:4995)
#define NORETURN __declspec (noreturn)
#define UNUSED
#define OPTIMIZE
#elif defined __GNUC__
#define NORETURN __attribute__ ((noreturn))
#define UNUSED __attribute__ ((unused))
#define OPTIMIZE(n) __attribute__ ((optimize ("O"#n)))
#else
#define NORETURN
#define UNUSED
#define OPTIMIZE
#endif

#ifdef __MINGW32__
/* some versions of MingW have non idempotent %p */
#include <inttypes.h>
#define FMT_ptr PRIxPTR
#define FMT_ptr_cast(p) ((intptr_t *) (p))
#define FMT_ptr_cast2(p) ((intptr_t) (p))
#else
#define FMT_ptr "p"
#define FMT_ptr_cast(p) (p)
#define FMT_ptr_cast2(p) (p)
#endif

#ifdef _WIN32
static void __declspec (noreturn) sockerr (int exitcode, const char *fmt, ...)
{
    va_list ap;

    va_start (ap, fmt);
    vfprintf (stderr, fmt, ap);
    va_end (ap);
    fprintf (stderr, ": wsaerror 0x%x\n", WSAGetLastError ());
    _exit (exitcode);
}
#else
#define FMT_ss "zd"
#define FMT_s "zu"
#define fionread_arg int
#define ioctlsocket ioctl
#define sockerr err
#include <unistd.h>
#endif

#include <regex.h>
#include <ctype.h>
#include <stdarg.h>
#include <limits.h>

#ifndef _WIN32
#include <pthread.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#endif

static void NORETURN err (int exitcode, const char *fmt, ...)
{
    va_list ap;
    int savederrno;

    savederrno = errno;
    va_start (ap, fmt);
    vfprintf (stderr, fmt, ap);
    va_end (ap);
    fprintf (stderr, ": %s\n", strerror (savederrno));
    fflush (stderr);
    _exit (exitcode);
}

static void NORETURN errx (int exitcode, const char *fmt, ...)
{
    va_list ap;

    va_start (ap, fmt);
    vfprintf (stderr, fmt, ap);
    va_end (ap);
    fputc ('\n', stderr);
    fflush (stderr);
    _exit (exitcode);
}

#ifdef __APPLE__
#include <OpenGL/gl.h>
#else
#include <GL/gl.h>
#endif

#ifndef GL_TEXTURE_RECTANGLE_ARB
#define GL_TEXTURE_RECTANGLE_ARB          0x84F5
#endif

#ifndef GL_BGRA
#define GL_BGRA                           0x80E1
#endif

#ifndef GL_UNSIGNED_INT_8_8_8_8
#define GL_UNSIGNED_INT_8_8_8_8           0x8035
#endif

#ifndef GL_UNSIGNED_INT_8_8_8_8_REV
#define GL_UNSIGNED_INT_8_8_8_8_REV       0x8367
#endif

#include <caml/fail.h>
#include <caml/alloc.h>
#include <caml/memory.h>
#include <caml/unixsupport.h>

#include <fitz.h>
#include <mupdf.h>

#include FT_FREETYPE_H

#if 0
#define lprintf printf
#else
#define lprintf(...)
#endif

#define ARSERT(cond) for (;;) {                         \
    if (!(cond)) {                                      \
        errx (1, "%s:%d " #cond, __FILE__, __LINE__);   \
    }                                                   \
    break;                                              \
}

struct slice {
    int h;
    int texindex;
};

struct tile {
    int x, y, w, h;
    int slicecount;
    int sliceheight;
    fz_pixmap *pixmap;
    struct slice slices[1];
};

struct pagedim {
    int pageno;
    int rotate;
    int left;
    int tctmready;
    fz_bbox bounds;
    fz_rect pagebox;
    fz_rect mediabox;
    fz_matrix ctm, zoomctm, lctm, tctm;
};

struct page {
    int gen;
    int pageno;
    int pdimno;
    fz_text_span *text;
    pdf_page *drawpage;
    fz_display_list *dlist;
    struct mark {
        int i;
        fz_text_span *span;
    } fmark, lmark;
};

#if !defined _WIN32 && !defined __APPLE__
#define USE_XSEL
#endif

struct {
    int sock;
    int sliceheight;
    struct pagedim *pagedims;
    int pagecount;
    int pagedimcount;
    pdf_document *doc;
    fz_context *ctx;
    fz_glyph_cache *cache;
    int w, h;

    int texindex;
    int texcount;
    GLuint *texids;

    GLenum texiform;
    GLenum texform;
    GLenum texty;

    fz_colorspace *colorspace;

    struct {
        int w, h;
        struct slice *slice;
    } *texowners;

    int rotate;
    int proportional;
    int trimmargins;
    int needoutline;
    int gen;
    int aalevel;

    int trimanew;
    fz_bbox trimfuzz;
    fz_pixmap *pig;

#ifdef _WIN32
    HANDLE thread;
#else
    pthread_t thread;
#endif
    FILE *xselpipe;

    FT_Face face;
} state;

static void UNUSED debug_rect (const char *cap, fz_rect r)
{
    printf ("%s(rect) %.2f,%.2f,%.2f,%.2f\n", cap, r.x0, r.y0, r.x1, r.y1);
}

static void UNUSED debug_bbox (const char *cap, fz_bbox r)
{
    printf ("%s(bbox) %d,%d,%d,%d\n", cap, r.x0, r.y0, r.x1, r.y1);
}

static void UNUSED debug_matrix (const char *cap, fz_matrix m)
{
    printf ("%s(matrix) %.2f,%.2f,%.2f,%.2f %.2f %.2f\n", cap,
            m.a, m.b, m.c, m.d, m.e, m.f);
}

#ifdef _WIN32
static CRITICAL_SECTION critsec;

static void lock (void *unused)
{
    (void) unused;
    EnterCriticalSection (&critsec);
}

static void unlock (void *unused)
{
    (void) unused;
    LeaveCriticalSection (&critsec);
}

static int trylock (void *unused)
{
    return TryEnterCriticalSection (&critsec) == 0;
}
#else
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

static void lock (const char *cap)
{
    int ret = pthread_mutex_lock (&mutex);
    if (ret) {
        errx (1, "%s: pthread_mutex_lock: %s", cap, strerror (ret));
    }
}

static void unlock (const char *cap)
{
    int ret = pthread_mutex_unlock (&mutex);
    if (ret) {
        errx (1, "%s: pthread_mutex_unlock: %s", cap, strerror (ret));
    }
}

static int trylock (const char *cap)
{
    int ret = pthread_mutex_trylock (&mutex);

    if (ret && ret != EBUSY) {
        errx (1, "%s: pthread_mutex_trylock: %s", cap, strerror (ret));
    }
    return ret == EBUSY;
}
#endif

static void *parse_pointer (const char *cap, const char *s)
{
    int ret;
    void *ptr;

    ret = sscanf (s, "%" FMT_ptr, FMT_ptr_cast (&ptr));
    if (ret != 1) {
        errx (1, "%s: cannot parse pointer in `%s'", cap, s);
    }
    return ptr;
}

static int hasdata (int sock)
{
    int ret;
    fionread_arg avail;
    ret = ioctlsocket (sock, FIONREAD, &avail);
    if (ret) sockerr (1, "hasdata: FIONREAD error ret=%d", ret);
    return avail > 0;
}

static double now (void)
{
#ifdef _WIN32
    FILETIME ft;
    uint64 tmp;

    GetSystemTimeAsFileTime (&ft);
    tmp = ft.dwHighDateTime;
    tmp <<= 32;
    tmp |= ft.dwLowDateTime;
    return tmp * 1e-7;
#else
    struct timeval tv;

    if (gettimeofday (&tv, NULL)) {
        err (1, "gettimeofday");
    }
    return tv.tv_sec + tv.tv_usec*1e-6;
#endif
}

static void readdata (int fd, char *p, int size)
{
    ssize_t n;

    n = recv (fd, p, size, 0);
    if (n - size) {
        if (!n) errx (1, "EOF while reading");
        sockerr (1, "recv (req %d, ret %" FMT_ss ")", size, n);
    }
}

static void writedata (int fd, char *p, int size)
{
    char buf[4];
    ssize_t n;

    buf[0] = (size >> 24) & 0xff;
    buf[1] = (size >> 16) & 0xff;
    buf[2] = (size >>  8) & 0xff;
    buf[3] = (size >>  0) & 0xff;

    n = send (fd, buf, 4, 0);
    if (n != 4) {
        if (!n) errx (1, "EOF while writing length");
        sockerr (1, "send %" FMT_ss, n);
    }

    n = send (fd, p, size, 0);
    if (n - size) {
        if (!n) errx (1, "EOF while writing data");
        sockerr (1, "send (req %d, ret %" FMT_ss ")", size, n);
    }
}

static void
#ifdef __GNUC__
__attribute__ ((format (printf, 2, 3)))
#endif
    printd (int fd, const char *fmt, ...)
{
    int size = 200, len;
    va_list ap;
    char *buf;

    buf = malloc (size);
    for (;;) {
        if (!buf) err (errno, "malloc for temp buf (%d bytes) failed", size);

        va_start (ap, fmt);
        len = vsnprintf (buf, size, fmt, ap);
        va_end (ap);

        if (len > -1 && len < size) {
            writedata (fd, buf, len);
            break;
        }

        if (len > -1) {
            size = len + 1;
        }
        else  {
            size *= 2;
        }
        buf = realloc (buf, size);
    }
    free (buf);
}

static void openxref (char *filename, char *password)
{
    int i;

    for (i = 0; i < state.texcount; ++i)  {
        state.texowners[i].w = -1;
        state.texowners[i].slice = NULL;
    }

   if (state.doc) {
        pdf_close_document (state.doc);
        state.doc = NULL;
    }

    if (state.pagedims) {
        free (state.pagedims);
        state.pagedims = NULL;
    }
    state.pagedimcount = 0;

    fz_set_aa_level (state.ctx, state.aalevel);
    state.doc = pdf_open_document (state.ctx, filename);
    if (pdf_needs_password (state.doc)) {
        int okay = pdf_authenticate_password (state.doc, password);
        if (!okay) {
            errx (1, "invalid password");
        }
    }
    state.pagecount = pdf_count_pages (state.doc);
}

static void pdfinfo (void)
{
    fz_obj *infoobj;

    printd (state.sock, "info PDF version\t%d.%d",
            state.doc->version / 10, state.doc->version % 10);

    infoobj = fz_dict_gets (state.doc->trailer, "Info");
    if (infoobj) {
        int i;
        char *s;
        char *items[] = { "Title", "Author", "Creator",
                          "Producer", "CreationDate" };

        for (i = 0; i < sizeof (items) / sizeof (*items); ++i) {
            fz_obj *obj = fz_dict_gets (infoobj, items[i]);
            s = pdf_to_utf8 (state.ctx, obj);
            if (*s) {
                if (i == 0) {
                    printd (state.sock, "title %s", s);
                }
                printd (state.sock, "info %s\t%s", items[i], s);
            }
            fz_free (state.ctx, s);
        }
    }
    printd (state.sock, "info Pages\t%d", state.pagecount);
    printd (state.sock, "info Dimensions\t%d", state.pagedimcount);
    printd (state.sock, "infoend");
}

static int readlen (int fd)
{
    ssize_t n;
    unsigned char p[4];

    n = recv (fd, p, 4, 0);
    if (n != 4) {
        if (!n) errx (1, "EOF while reading length");
        sockerr (1, "recv %" FMT_ss, n);
    }

    return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
}

static void unlinktile (struct tile *tile)
{
    int i;

    for (i = 0; i < tile->slicecount; ++i) {
        struct slice *s = &tile->slices[i];

        if (s->texindex != -1) {
            if (state.texowners[s->texindex].slice == s) {
                state.texowners[s->texindex].slice = NULL;
            }
        }
    }
}

static void freepage (struct page *page)
{
    if (page->text) {
        fz_free_text_span (state.ctx, page->text);
    }
    pdf_free_page (state.ctx, page->drawpage);
    fz_free_display_list (state.ctx, page->dlist);
    free (page);
}

static void freetile (struct tile *tile)
{
    unlinktile (tile);
#ifndef PIGGYBACK
    fz_drop_pixmap (state.ctx, tile->pixmap);
#else
    if (state.pig) {
        fz_drop_pixmap (state.ctx, state.pig);
    }
    state.pig = tile->pixmap;
#endif
    free (tile);
}

#ifdef __ALTIVEC__
#include <altivec.h>

static int cacheline32bytes;
extern char **environ;

static void __attribute__ ((constructor)) clcheck (void)
{
    char **envp = environ;
    unsigned long *auxv;

    while (*envp++);

    for (auxv = (unsigned long *) envp; *auxv != 0; auxv += 2) {
        if (*auxv == 19) {
            cacheline32bytes = auxv[1] == 32;
            return;
        }
    }
}

static void OPTIMIZE (3) clearpixmap (fz_pixmap *pixmap)
{
    if (cacheline32bytes) {
        intptr_t a1, a2, diff;
        size_t sizea, i, size = pixmap->w * pixmap->h * pixmap->n;
        vector unsigned char v = vec_splat_u8 (-1);
        vector unsigned char *p;

        a1 = a2 = (intptr_t) pixmap->samples;
        a2 = (a1 + 31) & ~31;
        diff = a2 - a1;
        sizea = size - diff;
        p = (void *) a2;

        while (a1 != a2) *(char *) a1++ = 0xff;
        for (i = 0; i < (sizea & ~31); i += 32)  {
            __asm volatile ("dcbz %0, %1"::"b"(a2),"r"(i));
            vec_st (v, i, p);
            vec_st (v, i + 16, p);
        }
        while (i < sizea) *((char *) a1 + i++) = 0xff;
    }
    else fz_clear_pixmap_with_color (pixmap, 0xff);
}
#else
#define clearpixmap(p) fz_clear_pixmap_with_color (p, 0xff)
#endif

static fz_matrix trimctm (pdf_page *page, int pindex)
{
    fz_matrix ctm;
    struct pagedim *pdim = &state.pagedims[pindex];

    if (!pdim->tctmready) {
        if (state.trimmargins) {
            fz_rect realbox;

            ctm = fz_concat (fz_rotate (-pdim->rotate), fz_scale (1, -1));
            realbox = fz_transform_rect (ctm, pdim->mediabox);
            ctm = fz_concat (ctm, fz_translate (-realbox.x0, -realbox.y0));
            ctm = fz_concat (fz_invert_matrix (page->ctm), ctm);
        }
        else {
            ctm = fz_identity;
        }
        pdim->tctm = ctm;
        pdim->tctmready = 1;
    }
    return pdim->tctm;
}

static fz_matrix pagectm (struct page *page)
{
    return fz_concat (trimctm (page->drawpage, page->pdimno),
                      state.pagedims[page->pdimno].ctm);
}

static void *loadpage (int pageno, int pindex)
{
    fz_device *dev;
    struct page *page = NULL;

    page = calloc (sizeof (struct page), 1);
    if (!page) {
        err (1, "calloc page %d", pageno);
    }

    page->drawpage = pdf_load_page (state.doc, pageno);
    page->dlist = fz_new_display_list (state.ctx);
    dev = fz_new_list_device (state.ctx, page->dlist);
    pdf_run_page (state.doc, page->drawpage, dev, fz_identity, NULL);
    fz_free_device (dev);

    page->pdimno = pindex;
    page->pageno = pageno;
    page->gen = state.gen;

    return page;
}

static struct tile *alloctile (int h)
{
    int i;
    int slicecount;
    size_t tilesize;
    struct tile *tile;

    slicecount = (h + state.sliceheight - 1) / state.sliceheight;
    tilesize = sizeof (*tile) + ((slicecount - 1) * sizeof (struct slice));
    tile = calloc (tilesize, 1);
    if (!tile) {
        err (1, "can not allocate tile (%" FMT_s " bytes)", tilesize);
    }
    for (i = 0; i < slicecount; ++i) {
        int sh = MIN (h, state.sliceheight);
        tile->slices[i].h = sh;
        tile->slices[i].texindex = -1;
        h -= sh;
    }
    tile->slicecount = slicecount;
    tile->sliceheight = state.sliceheight;
    return tile;
}

static struct tile *rendertile (struct page *page, int x, int y, int w, int h)
{
    fz_bbox bbox;
    fz_device *dev;
    struct tile *tile;
    struct pagedim *pdim;

    tile = alloctile (h);
    pdim = &state.pagedims[page->pdimno];

    bbox = pdim->bounds;
    bbox.x0 += x;
    bbox.y0 += y;
    bbox.x1 = bbox.x0 + w;
    bbox.y1 = bbox.y0 + h;

    if (state.pig) {
        if (state.pig->w == w
            && state.pig->h == h
            && state.pig->colorspace == state.colorspace) {
            tile->pixmap = state.pig;
            tile->pixmap->x = bbox.x0;
            tile->pixmap->y = bbox.y0;
        }
        else {
            fz_drop_pixmap (state.ctx, state.pig);
        }
        state.pig = NULL;
    }
    if (!tile->pixmap) {
        tile->pixmap =
            fz_new_pixmap_with_rect (state.ctx, state.colorspace, bbox);
    }

    tile->w = w;
    tile->h = h;
    clearpixmap (tile->pixmap);
    dev = fz_new_draw_device (state.ctx, tile->pixmap);
    fz_execute_display_list (page->dlist, dev, pagectm (page), bbox, NULL);
    fz_free_device (dev);

    return tile;
}

static void initpdims (void)
{
    int pageno;
    double start, end;

    start = now ();
    for (pageno = 0; pageno < state.pagecount; ++pageno) {
        int rotate;
        fz_obj *pageobj;
        struct pagedim *p;
        fz_rect mediabox, cropbox;

        pageobj = state.doc->page_objs[pageno];

        if (state.trimmargins) {
            fz_obj *obj;
            pdf_page *page;

            page = pdf_load_page (state.doc, pageno);
            obj = fz_dict_gets (pageobj, "llpp.TrimBox");
            if (state.trimanew || !obj) {
                fz_rect rect;
                fz_bbox bbox;
                fz_matrix ctm;
                fz_device *dev;

                dev = fz_new_bbox_device (state.ctx, &bbox);
                dev->hints |= FZ_IGNORE_SHADE;
                ctm = fz_invert_matrix (page->ctm);
                pdf_run_page (state.doc, page, dev, fz_identity, NULL);
                fz_free_device (dev);

                rect.x0 = bbox.x0 + state.trimfuzz.x0;
                rect.x1 = bbox.x1 + state.trimfuzz.x1;
                rect.y0 = bbox.y0 + state.trimfuzz.y0;
                rect.y1 = bbox.y1 + state.trimfuzz.y1;
                rect = fz_transform_rect (ctm, rect);
                rect = fz_intersect_rect (rect, page->mediabox);

                if (fz_is_empty_rect (rect)) {
                    mediabox = page->mediabox;
                }
                else {
                    mediabox = rect;
                }

                obj = fz_new_array (state.ctx, 4);
                fz_array_push (obj, fz_new_real (state.ctx, mediabox.x0));
                fz_array_push (obj, fz_new_real (state.ctx, mediabox.y0));
                fz_array_push (obj, fz_new_real (state.ctx, mediabox.x1));
                fz_array_push (obj, fz_new_real (state.ctx, mediabox.y1));
                fz_dict_puts (pageobj, "llpp.TrimBox", obj);
            }
            else {
                mediabox.x0 = fz_to_real (fz_array_get (obj, 0));
                mediabox.y0 = fz_to_real (fz_array_get (obj, 1));
                mediabox.x1 = fz_to_real (fz_array_get (obj, 2));
                mediabox.y1 = fz_to_real (fz_array_get (obj, 3));
            }

            rotate = page->rotate;
            pdf_free_page (state.ctx, page);

            printd (state.sock, "progress %f Trimming %d",
                    (double) (pageno + 1) / state.pagecount,
                    pageno + 1);
        }
        else {
            mediabox = pdf_to_rect (state.ctx, fz_dict_gets (pageobj, "MediaBox"));
            if (fz_is_empty_rect (mediabox)) {
                fprintf (stderr, "cannot find page size for page %d\n", pageno+1);
                mediabox.x0 = 0;
                mediabox.y0 = 0;
                mediabox.x1 = 612;
                mediabox.y1 = 792;
            }

            cropbox = pdf_to_rect (state.ctx, fz_dict_gets (pageobj, "CropBox"));
            if (!fz_is_empty_rect (cropbox)) {
                mediabox = fz_intersect_rect (mediabox, cropbox);
            }
            rotate = fz_to_int (fz_dict_gets (pageobj, "Rotate"));
        }

        if (state.pagedimcount == 0
            || (p = &state.pagedims[state.pagedimcount-1], p->rotate != rotate)
            || memcmp (&p->mediabox, &mediabox, sizeof (mediabox))) {
            size_t size;

            size = (state.pagedimcount + 1) * sizeof (*state.pagedims);
            state.pagedims = realloc (state.pagedims, size);
            if (!state.pagedims) {
                err (1, "realloc pagedims to %" FMT_s " (%d elems)",
                     size, state.pagedimcount + 1);
            }

            p = &state.pagedims[state.pagedimcount++];
            p->rotate = rotate;
            p->mediabox = mediabox;
            p->pageno = pageno;
        }
    }
    end = now ();
    if (state.trimmargins) {
        printd (state.sock, "progress 1 Trimmed %d pages in %f seconds",
                state.pagecount, end - start);
    }
    else {
        printd (state.sock, "vmsg Processed %d pages in %f seconds",
                state.pagecount, end - start);
    }
    state.trimanew = 0;
}

static void layout (void)
{
    int pindex;
    fz_rect box;
    fz_matrix ctm;
    double zoom, w, maxw = 0;
    struct pagedim *p = state.pagedims;

    if (state.proportional) {
        for (pindex = 0; pindex < state.pagedimcount; ++pindex, ++p) {
            box = fz_transform_rect (fz_rotate (p->rotate + state.rotate),
                                     p->mediabox);
            w = box.x1 - box.x0;
            maxw = MAX (w, maxw);
        }
    }

    p = state.pagedims;
    for (pindex = 0; pindex < state.pagedimcount; ++pindex, ++p) {
        fz_bbox bbox;

        ctm = fz_rotate (state.rotate);
        box = fz_transform_rect (fz_rotate (p->rotate + state.rotate),
                                 p->mediabox);
        w = box.x1 - box.x0;

        if (state.proportional) {
            double scale = w / maxw;
            zoom = (state.w / w) * scale;
        }
        else {
            zoom = state.w / w;
        }

        p->zoomctm = fz_scale (zoom, zoom);
        ctm = fz_concat (p->zoomctm, ctm);

        p->pagebox = fz_transform_rect (fz_rotate (p->rotate), p->mediabox);
        p->pagebox.x1 -= p->pagebox.x0;
        p->pagebox.y1 -= p->pagebox.y0;
        p->pagebox.x0 = 0;
        p->pagebox.y0 = 0;
        bbox = fz_round_rect (fz_transform_rect (ctm, p->pagebox));

        p->bounds = bbox;
        p->left = state.proportional ? ((maxw - w) * zoom) / 2.0 : 0;
        p->ctm = ctm;

        ctm = fz_identity;
        ctm = fz_concat (ctm, fz_translate (0, -p->mediabox.y1));
        ctm = fz_concat (ctm, fz_scale (zoom, -zoom));
        ctm = fz_concat (ctm, fz_rotate (p->rotate + state.rotate));
        p->lctm = ctm;

        p->tctmready = 0;
    }

    while (p-- != state.pagedims)  {
        int w = p->bounds.x1 - p->bounds.x0;
        int h = p->bounds.y1 - p->bounds.y0;

        printd (state.sock, "pdim %d %d %d %d", p->pageno, w, h, p->left);
    }
}

static void recurse_outline (fz_outline *outline, int level)
{
    while (outline) {
        fz_link_dest *dest;
        int i, top = 0;
        struct pagedim *pdim = state.pagedims;

        dest = &outline->dest;
        for (i = 0; i < state.pagedimcount; ++i) {
            if (state.pagedims[i].pageno > dest->ld.gotor.page)
                break;
            pdim = &state.pagedims[i];
        }
        if (dest->ld.gotor.flags & fz_link_flag_t_valid) {
            fz_point p;
            p.x = 0;
            p.y = dest->ld.gotor.lt.y;
            p = fz_transform_point (pdim->lctm, p);
            top = p.y;
        }
        if (dest->ld.gotor.page >= 0 && dest->ld.gotor.page < 1<<30) {
            int h;
            double y0, y1;

            y0 = MIN (pdim->bounds.y0, pdim->bounds.y1);
            y1 = MAX (pdim->bounds.y0, pdim->bounds.y1);
            h = y1 - y0;
            printd (state.sock, "o %d %d %d %d %s",
                    level, dest->ld.gotor.page, top, h, outline->title);
        }
        if (outline->down) {
            recurse_outline (outline->down, level + 1);
        }
        outline = outline->next;
    }
}

static void process_outline (void)
{
    fz_outline *outline;

    if (!state.needoutline) return;

    state.needoutline = 0;
    outline = pdf_load_outline (state.doc);
    if (outline) {
        recurse_outline (outline, 0);
        fz_free_outline (outline);
    }
}

static int comparespans (const void *l, const void *r)
{
    fz_text_span const *const*ls = l;
    fz_text_span const *const*rs = r;
    return (*ls)->text->bbox.y0 - (*rs)->text->bbox.y0;
}

/* wishful thinking function */
static void search (regex_t *re, int pageno, int y, int forward)
{
    int i, j;
    int ret;
    char *p;
    char buf[256];
    fz_matrix ctm;
    fz_device *tdev;
    pdf_page *drawpage;
    fz_text_span *text, *span, **pspan;
    struct pagedim *pdim, *pdimprev;
    int stop = 0;
    int niters = 0;
    int nspans;
    double start, end;

    start = now ();
    while (pageno >= 0 && pageno < state.pagecount && !stop) {
        if (niters++ == 5) {
            niters = 0;
            if (hasdata (state.sock)) {
                printd (state.sock,
                        "progress 1 attention requested aborting search at %d",
                        pageno);
                stop = 1;
            }
            else {
                printd (state.sock, "progress %f searching in page %d",
                        (double) (pageno + 1) / state.pagecount,
                        pageno);
            }
        }
        pdimprev = NULL;
        for (i = 0; i < state.pagedimcount; ++i) {
            pdim = &state.pagedims[i];
            if (pdim->pageno == pageno)  {
                goto found;
            }
            if (pdim->pageno > pageno) {
                pdim = pdimprev;
                goto found;
            }
            pdimprev = pdim;
        }
        pdim = pdimprev;
    found:

        drawpage = pdf_load_page (state.doc, pageno);

        text = fz_new_text_span (state.ctx);
        tdev = fz_new_text_device (state.ctx, text);
        pdf_run_page (state.doc, drawpage, tdev, fz_identity, NULL);
        fz_free_device (tdev);

        nspans = 0;
        for (span = text; span; span = span->next) {
            nspans++;
        }
        pspan = malloc (sizeof (void *) * nspans);
        if (!pspan) {
            err (1, "malloc span pointers %" FMT_s, sizeof (void *) * nspans);
        }
        for (i = 0, span = text; span; span = span->next, ++i) {
            pspan[i] = span;
        }
        qsort (pspan, nspans, sizeof (fz_text_span *), comparespans);

        j = forward ? 0 : nspans - 1;
        while (nspans--) {
            regmatch_t rm;

            span = pspan[j];
            j += forward ? 1 : -1;
            p = buf;
            for (i = 0; i < MIN (span->len, (int) sizeof (buf) - 1); ++i) {
                if (forward) {
                    if (span->text[i].bbox.y0 < y + 1) {
                        continue;
                    }
                }
                else {
                    if (span->text[i].bbox.y0 > y - 1) {
                        continue;
                    }
                }
                if (span->text[i].c < 256) {
                    *p++ = span->text[i].c;
                }
                else  {
                    *p++ = '?';
                }
            }
            if (p == buf) {
                continue;
            }
            *p++ = 0;

            ret = regexec (re, buf, 1, &rm, 0);
            if (ret)  {
                if (ret != REG_NOMATCH) {
                    size_t size;
                    char errbuf[80];
                    size = regerror (ret, re, errbuf, sizeof (errbuf));
                    printd (state.sock,
                            "msg regexec error `%.*s'",
                            (int) size, errbuf);
                    fz_free_text_span (state.ctx, text);
                    pdf_free_page (state.ctx, drawpage);
                    free (pspan);
                    return;
                }
            }
            else  {
                fz_bbox *sb, *eb;
                fz_point p1, p2, p3, p4;

                sb = &span->text[rm.rm_so].bbox;
                eb = &span->text[rm.rm_eo - 1].bbox;

                p1.x = sb->x0;
                p1.y = sb->y0;
                p2.x = eb->x1;
                p2.y = sb->y0;
                p3.x = eb->x1;
                p3.y = eb->y1;
                p4.x = sb->x0;
                p4.y = eb->y1;

                trimctm (drawpage, pdim - state.pagedims);
                ctm = fz_concat (pdim->tctm, pdim->zoomctm);

                p1 = fz_transform_point (ctm, p1);
                p2 = fz_transform_point (ctm, p2);
                p3 = fz_transform_point (ctm, p3);
                p4 = fz_transform_point (ctm, p4);

                if (!stop) {
                    printd (state.sock,
                            "firstmatch %d %d %f %f %f %f %f %f %f %f",
                            pageno, 1,
                            p1.x, p1.y,
                            p2.x, p2.y,
                            p3.x, p3.y,
                            p4.x, p4.y);

                    printd (state.sock,
                            "progress 1 found at %d `%.*s' in %f sec",
                            pageno, (int) (rm.rm_eo - rm.rm_so), &buf[rm.rm_so],
                            now () - start);
                }
                else  {
                    printd (state.sock,
                            "match %d %d %f %f %f %f %f %f %f %f",
                            pageno, 2,
                            p1.x, p1.y,
                            p2.x, p2.y,
                            p3.x, p3.y,
                            p4.x, p4.y);
                }
                stop = 1;
            }
        }
        if (forward) {
            pageno += 1;
            y = 0;
        }
        else {
            pageno -= 1;
            y = INT_MAX;
        }
        fz_free_text_span (state.ctx, text);
        pdf_free_page (state.ctx, drawpage);
        free (pspan);
    }
    end = now ();
    if (!stop)  {
        printd (state.sock, "progress 1 no matches %f sec", end - start);
    }
    printd (state.sock, "clearrects");
}

static void set_tex_params (int colorspace)
{
    switch (colorspace) {
    case 0:
        state.texiform = GL_RGBA8;
        state.texform = GL_RGBA;
        state.texty = GL_UNSIGNED_BYTE;
        state.colorspace = fz_device_rgb;
        break;
    case 1:
        state.texiform = GL_RGBA8;
        state.texform = GL_BGRA;
        state.texty = fz_is_big_endian ()
            ? GL_UNSIGNED_INT_8_8_8_8
            : GL_UNSIGNED_INT_8_8_8_8_REV;
        state.colorspace = fz_device_bgr;
        break;
    case 2:
        state.texiform = GL_LUMINANCE_ALPHA;
        state.texform = GL_LUMINANCE_ALPHA;
        state.texty = GL_UNSIGNED_BYTE;
        state.colorspace = fz_device_gray;
        break;
    default:
        errx (1, "invalid colorspce %d", colorspace);
    }
}

static void realloctexts (int texcount)
{
    size_t size;

    if (texcount == state.texcount) return;

    if (texcount < state.texcount) {
        glDeleteTextures (state.texcount - texcount,
                          state.texids + texcount);
    }

    size = texcount * sizeof (*state.texids);
    state.texids = realloc (state.texids, size);
    if (!state.texids) {
        err (1, "realloc texids %" FMT_s, size);
    }

    size = texcount * sizeof (*state.texowners);
    state.texowners = realloc (state.texowners, size);
    if (!state.texowners) {
        err (1, "realloc texowners %" FMT_s, size);
    }
    if (texcount > state.texcount) {
        int i;

        glGenTextures (texcount - state.texcount,
                       state.texids + state.texcount);
        for (i = state.texcount; i < texcount; ++i) {
            state.texowners[i].w = -1;
            state.texowners[i].slice = NULL;
        }
    }
    state.texcount = texcount;
    state.texindex = 0;
}

static
#ifdef _WIN32
DWORD _stdcall
#else
void *
#endif
mainloop (void *unused)
{
    char *p = NULL;
    int len, ret, oldlen = 0;

    for (;;) {
        len = readlen (state.sock);
        if (len == 0) {
            errx (1, "readlen returned 0");
        }

        if (oldlen < len + 1) {
            p = realloc (p, len + 1);
            if (!p) {
                err (1, "realloc %d failed", len + 1);
            }
            oldlen = len + 1;
        }
        readdata (state.sock, p, len);
        p[len] = 0;

        if (!strncmp ("open", p, 4)) {
            size_t filenamelen;
            char *password;
            char *filename = p + 5;

            filenamelen = strlen (filename);
            password = filename + filenamelen + 1;

            openxref (filename, password);
            printd (state.sock, "msg Opened %s (press h/F1 to get help)",
                    filename);
            pdfinfo ();
            initpdims ();
            state.needoutline = 1;
        }
        else if (!strncmp ("cs", p, 2)) {
            int i, colorspace;

            ret = sscanf (p + 2, " %d", &colorspace);
            if (ret != 1) {
                errx (1, "malformed cs `%.*s' ret=%d", len, p, ret);
            }
            lock ("cs");
            set_tex_params (colorspace);
            for (i = 0; i < state.texcount; ++i)  {
                state.texowners[i].w = -1;
                state.texowners[i].slice = NULL;
            }
            unlock ("cs");
        }
        else if (!strncmp ("freepage", p, 8)) {
            void *ptr;

            ret = sscanf (p + 8, " %" FMT_ptr, FMT_ptr_cast (&ptr));
            if (ret != 1) {
                errx (1, "malformed freepage `%.*s' ret=%d", len, p, ret);
            }
            freepage (ptr);
        }
        else if (!strncmp ("freetile", p, 8)) {
            void *ptr;

            ret = sscanf (p + 8, " %" FMT_ptr, FMT_ptr_cast (&ptr));
            if (ret != 1) {
                errx (1, "malformed freetile `%.*s' ret=%d", len, p, ret);
            }
            freetile (ptr);
        }
        else if (!strncmp ("search", p, 6)) {
            int icase, pageno, y, ret, len2, forward;
            char *pattern;
            regex_t re;

            ret = sscanf (p + 6, " %d %d %d %d,%n",
                          &icase, &pageno, &y, &forward, &len2);
            if (ret != 4) {
                errx (1, "malformed search `%s' ret=%d", p, ret);
            }

            pattern = p + 6 + len2;
            ret = regcomp (&re, pattern,
                           REG_EXTENDED | (icase ? REG_ICASE : 0));
            if (ret) {
                char errbuf[80];
                size_t size;

                size = regerror (ret, &re, errbuf, sizeof (errbuf));
                printd (state.sock, "msg regcomp failed `%.*s'",
                        (int) size, errbuf);
            }
            else  {
                search (&re, pageno, y, forward);
                regfree (&re);
            }
        }
        else if (!strncmp ("geometry", p, 8)) {
            int w, h;

            printd (state.sock, "clear");
            ret = sscanf (p + 8, " %d %d", &w, &h);
            if (ret != 2) {
                errx (1, "malformed geometry `%.*s' ret=%d", len, p, ret);
            }

            lock ("geometry");
            state.h = h;
            if (w != state.w) {
                int i;
                state.w = w;
                for (i = 0; i < state.texcount; ++i)  {
                    state.texowners[i].slice = NULL;
                }
            }
            layout ();
            process_outline ();
            state.gen++;
            unlock ("geometry");
            printd (state.sock, "continue %d", state.pagecount);
        }
        else if (!strncmp ("reqlayout", p, 9)) {
            int rotate, proportional;

            printd (state.sock, "clear");
            ret = sscanf (p + 9, " %d %d", &rotate, &proportional);
            if (ret != 2) {
                errx (1, "bad reqlayout line `%.*s' ret=%d", len, p, ret);
            }
            lock ("reqlayout");
            state.rotate = rotate;
            state.proportional = proportional;
            layout ();
            unlock ("reqlayout");
            printd (state.sock, "continue %d", state.pagecount);
        }
        else if (!strncmp ("page", p, 4)) {
            double a, b;
            struct page *page;
            int pageno, pindex, ret;

            ret = sscanf (p + 4, " %d %d", &pageno, &pindex);
            if (ret != 2) {
                errx (1, "bad render line `%.*s' ret=%d", len, p, ret);
            }

            lock ("page");
            a = now ();
            page = loadpage (pageno, pindex);
            b = now ();
            unlock ("page");

            printd (state.sock, "page %" FMT_ptr " %f",
                    FMT_ptr_cast2 (page), b - a);
        }
        else if (!strncmp ("tile", p, 4)) {
            int x, y, w, h, ret;
            struct page *page;
            struct tile *tile;
            double a, b;

            ret = sscanf (p + 4, " %" FMT_ptr " %d %d %d %d",
                          FMT_ptr_cast (&page), &x, &y, &w, &h);
            if (ret != 5) {
                errx (1, "bad tile line `%.*s' ret=%d", len, p, ret);
            }

            lock ("tile");
            a = now ();
            tile = rendertile (page, x, y, w, h);
            b = now ();
            unlock ("tile");

            printd (state.sock, "tile %d %d %" FMT_ptr " %u %f",
                    x, y,
                    FMT_ptr_cast2 (tile),
                    tile->w * tile->h * tile->pixmap->n,
                    b - a);
        }
        else if (!strncmp ("settrim", p, 7))  {
            int trimmargins;
            fz_bbox fuzz;

            ret = sscanf (p + 7, " %d %d %d %d %d", &trimmargins,
                          &fuzz.x0, &fuzz.y0, &fuzz.x1, &fuzz.y1);
            if (ret != 5) {
                errx (1, "malformed settrim `%.*s' ret=%d", len, p, ret);
            }
            printd (state.sock, "clear");
            lock ("settrim");
            state.trimmargins = trimmargins;
            state.needoutline = 1;
            if (memcmp (&fuzz, &state.trimfuzz, sizeof (fuzz))) {
                state.trimanew = 1;
                state.trimfuzz = fuzz;
            }
            state.pagedimcount = 0;
            free (state.pagedims);
            state.pagedims = NULL;
            initpdims ();
            layout ();
            process_outline ();
            unlock ("settrim");
            printd (state.sock, "continue %d", state.pagecount);
        }
        else if (!strncmp ("sliceh", p, 6)) {
            int h;

            ret = sscanf (p + 6, " %d", &h);
            if (ret != 1) {
                errx (1, "malformed sliceh `%.*s' ret=%d", len, p, ret);
            }
            if (h != state.sliceheight) {
                int i;

                state.sliceheight = h;
                for (i = 0; i < state.texcount; ++i) {
                    state.texowners[i].w = -1;
                    state.texowners[i].h = -1;
                    state.texowners[i].slice = NULL;
                }
            }
        }
        else if (!strncmp ("interrupt", p, 9)) {
            printd (state.sock, "vmsg interrupted");
        }
        else if (!strncmp ("quit", p, 4)) {
            return 0;
        }
        else {
            errx (1, "unknown command %.*s", len, p);
        }
    }
    return 0;
}

CAMLprim value ml_realloctexts (value texcount_v)
{
    CAMLparam1 (texcount_v);
    int ok;

    if (trylock ("ml_realloctexts")) {
        ok = 0;
        goto done;
    }
    realloctexts (Int_val (texcount_v));
    ok = 1;
    unlock ("ml_realloctexts");

 done:
    CAMLreturn (Val_bool (ok));
}

static void showsel (struct page *page, int ox, int oy)
{
    fz_bbox bbox;
    fz_text_span *span;
    struct mark first, last;

    first = page->fmark;
    last = page->lmark;

    if (!first.span || !last.span) return;

    glEnable (GL_BLEND);
    glBlendFunc (GL_SRC_ALPHA, GL_SRC_ALPHA);
    glColor4f (0.5f, 0.5f, 0.0f, 0.6f);

    ox -= state.pagedims[page->pdimno].bounds.x0;
    oy -= state.pagedims[page->pdimno].bounds.y0;
    for (span = first.span; span; span = span->next) {
        int i, j, k;

        bbox.x0 = bbox.y0 = bbox.x1 = bbox.y1 = 0;

        j = 0;
        k = span->len - 1;

        if (span == page->fmark.span && span == page->lmark.span) {
            j = MIN (first.i, last.i);
            k = MAX (first.i, last.i);
        }
        else if (span == first.span) {
            j = first.i;
        }
        else if (span == last.span) {
            k = last.i;
        }

        for (i = j; i <= k; ++i) {
            bbox = fz_union_bbox (bbox, span->text[i].bbox);
        }
        lprintf ("%d %d %d %d oy=%d ox=%d\n",
                 bbox.x0,
                 bbox.y0,
                 bbox.x1,
                 bbox.y1,
                 oy, ox);

        glRecti (bbox.x0 + ox, bbox.y0 + oy, bbox.x1 + ox, bbox.y1 + oy);

        if (span == last.span) break;
    }
    glDisable (GL_BLEND);
}

static void highlightlinks (struct page *page, int xoff, int yoff)
{
    fz_link *link;
    fz_matrix ctm;

    glPolygonMode (GL_FRONT_AND_BACK, GL_LINE);
    glEnable (GL_LINE_STIPPLE);
    glLineStipple (0.5, 0xcccc);

    ctm = fz_concat (pagectm (page), fz_translate (xoff, yoff));

    glBegin (GL_QUADS);
    for (link = page->drawpage->links; link; link = link->next) {
        fz_point p1, p2, p3, p4;

        p1.x = link->rect.x0;
        p1.y = link->rect.y0;

        p2.x = link->rect.x1;
        p2.y = link->rect.y0;

        p3.x = link->rect.x1;
        p3.y = link->rect.y1;

        p4.x = link->rect.x0;
        p4.y = link->rect.y1;

        p1 = fz_transform_point (ctm, p1);
        p2 = fz_transform_point (ctm, p2);
        p3 = fz_transform_point (ctm, p3);
        p4 = fz_transform_point (ctm, p4);

        switch (link->dest.kind) {
        case FZ_LINK_GOTO: glColor3ub (255, 0, 0); break;
        case FZ_LINK_URI: glColor3ub (0, 0, 255); break;
        default: glColor3ub (0, 0, 0); break;
        }

        glVertex2f (p1.x, p1.y);
        glVertex2f (p2.x, p2.y);
        glVertex2f (p3.x, p3.y);
        glVertex2f (p4.x, p4.y);
    }
    glEnd ();

    glPolygonMode (GL_FRONT_AND_BACK, GL_FILL);
    glDisable (GL_LINE_STIPPLE);
}

static void uploadslice (struct tile *tile, struct slice *slice)
{
    int offset;
    struct slice *slice1;

    offset = 0;
    for (slice1 = tile->slices; slice != slice1; slice1++) {
        offset += slice1->h * tile->w * tile->pixmap->n;
    }
    if (slice->texindex != -1 && slice->texindex < state.texcount
        && state.texowners[slice->texindex].slice == slice) {
        glBindTexture (GL_TEXTURE_RECTANGLE_ARB, state.texids[slice->texindex]);
    }
    else {
        int subimage = 0;
        int texindex = state.texindex++ % state.texcount;

        if (state.texowners[texindex].w == tile->w) {
            if (state.texowners[texindex].h >= slice->h) {
                subimage = 1;
            }
            else {
                state.texowners[texindex].h = slice->h;
            }
        }
        else  {
            state.texowners[texindex].h = slice->h;
        }

        state.texowners[texindex].w = tile->w;
        state.texowners[texindex].slice = slice;
        slice->texindex = texindex;

        glBindTexture (GL_TEXTURE_RECTANGLE_ARB, state.texids[texindex]);
        if (subimage) {
            glTexSubImage2D (GL_TEXTURE_RECTANGLE_ARB,
                             0,
                             0,
                             0,
                             tile->w,
                             slice->h,
                             state.texform,
                             state.texty,
                             tile->pixmap->samples+offset
                );
        }
        else {
            glTexImage2D (GL_TEXTURE_RECTANGLE_ARB,
                          0,
                          state.texiform,
                          tile->w,
                          slice->h,
                          0,
                          state.texform,
                          state.texty,
                          tile->pixmap->samples+offset
                );
        }
    }
}

CAMLprim value ml_drawtile (value args_v, value ptr_v)
{
    CAMLparam2 (args_v, ptr_v);
    int dispx = Int_val (Field (args_v, 0));
    int dispy = Int_val (Field (args_v, 1));
    int dispw = Int_val (Field (args_v, 2));
    int disph = Int_val (Field (args_v, 3));
    int tilex = Int_val (Field (args_v, 4));
    int tiley = Int_val (Field (args_v, 5));
    char *s = String_val (ptr_v);
    struct tile *tile = parse_pointer ("ml_drawtile", s);

    glEnable (GL_TEXTURE_RECTANGLE_ARB);
    {
        int slicey, firstslice;
        struct slice *slice;

        firstslice = tiley / tile->sliceheight;
        slice = &tile->slices[firstslice];
        slicey = tiley % tile->sliceheight;

        while (disph > 0) {
            int dh;

            dh = slice->h - slicey;
            dh = MIN (disph, dh);
            uploadslice (tile, slice);

            glBegin (GL_QUADS);
            {
                glTexCoord2i (tilex, slicey);
                glVertex2i (dispx, dispy);

                glTexCoord2i (tilex+dispw, slicey);
                glVertex2i (dispx+dispw, dispy);

                glTexCoord2i (tilex+dispw, slicey+dh);
                glVertex2i (dispx+dispw, dispy+dh);

                glTexCoord2i (tilex, slicey+dh);
                glVertex2i (dispx, dispy+dh);
            }
            glEnd ();

            dispy += dh;
            disph -= dh;
            slice++;
            ARSERT (!(slice - tile->slices >= tile->slicecount && disph > 0));
            slicey = 0;
        }
    }
    glDisable (GL_TEXTURE_RECTANGLE_ARB);
    CAMLreturn (Val_unit);
}

CAMLprim value ml_postprocess (value ptr_v, value hlinks_v,
                               value xoff_v, value yoff_v)
{
    CAMLparam4 (ptr_v, hlinks_v, xoff_v, yoff_v);
    int xoff = Int_val (xoff_v);
    int yoff = Int_val (yoff_v);
    char *s = String_val (ptr_v);
    struct page *page = parse_pointer ("ml_postprocess", s);

    if (Bool_val (hlinks_v)) highlightlinks (page, xoff, yoff);

    if (trylock ("ml_postprocess")) {
        goto done;
    }
    showsel (page, xoff, yoff);
    unlock ("ml_postprocess");

 done:
    CAMLreturn (Val_unit);
}

static fz_link *getlink (struct page *page, int x, int y)
{
    fz_point p;
    fz_matrix ctm;
    fz_link *link;

    p.x = x;
    p.y = y;

    ctm = fz_concat (trimctm (page->drawpage, page->pdimno),
                     state.pagedims[page->pdimno].ctm);
    ctm = fz_invert_matrix (ctm);
    p = fz_transform_point (ctm, p);

    for (link = page->drawpage->links; link; link = link->next) {
        if (p.x >= link->rect.x0 && p.x <= link->rect.x1) {
            if (p.y >= link->rect.y0 && p.y <= link->rect.y1) {
                return link;
            }
        }
    }
    return NULL;
}

static void droptext (struct page *page)
{
    if (page->text) {
        fz_free_text_span (state.ctx, page->text);
        page->fmark.i = -1;
        page->lmark.i = -1;
        page->fmark.span = NULL;
        page->lmark.span = NULL;
        page->text = NULL;
    }
}

static void ensuretext (struct page *page)
{
    if (state.gen != page->gen) {
        droptext (page);
        page->gen = state.gen;
    }
    if (!page->text) {
        fz_device *tdev;

        page->text = fz_new_text_span (state.ctx);
        tdev = fz_new_text_device (state.ctx, page->text);
        fz_execute_display_list (page->dlist,
                                 tdev,
                                 pagectm (page),
                                 fz_infinite_bbox, NULL);
        fz_free_device (tdev);
    }
}

CAMLprim value ml_whatsunder (value ptr_v, value x_v, value y_v)
{
    CAMLparam3 (ptr_v, x_v, y_v);
    CAMLlocal3 (ret_v, tup_v, str_v);
    fz_link *link;
    struct page *page;
    char *s = String_val (ptr_v);
    int x = Int_val (x_v), y = Int_val (y_v);
    struct pagedim *pdim;

    ret_v = Val_int (0);
    if (trylock ("ml_whatsunder")) {
        goto done;
    }

    page = parse_pointer ("ml_whatsunder", s);
    pdim = &state.pagedims[page->pdimno];
    x += pdim->bounds.x0;
    y += pdim->bounds.y0;
    link = getlink (page, x, y);
    if (link) {
        switch (link->dest.kind) {
        case FZ_LINK_GOTO:
            {
                int pageno;
                fz_point p;

                pageno = link->dest.ld.gotor.page;
                p.x = 0;
                p.y = 0;

                if (link->dest.ld.gotor.flags & fz_link_flag_t_valid) {
                    p.y = link->dest.ld.gotor.lt.y;
                    p = fz_transform_point (pdim->lctm, p);
                }
                tup_v = caml_alloc_tuple (2);
                ret_v = caml_alloc_small (1, 1);
                Field (tup_v, 0) = Val_int (pageno);
                Field (tup_v, 1) = Val_int (p.y);
                Field (ret_v, 0) = tup_v;
            }
            break;

        case FZ_LINK_URI:
            str_v = caml_copy_string (link->dest.ld.uri.uri);
            ret_v = caml_alloc_small (1, 0);
            Field (ret_v, 0) = str_v;
            break;

        default:
            printd (state.sock, "msg unhandled link kind %d", link->dest.kind);
            break;
        }
    }
    else {
        int i;
        fz_text_span *span;

        ensuretext (page);
        for (span = page->text; span; span = span->next) {
            for (i = 0; i < span->len; ++i) {
                fz_bbox *b;
                b = &span->text[i].bbox;
                if ((x >= b->x0 && x <= b->x1 && y >= b->y0 && y <= b->y1)) {
                    const char *n2 =
                        span->font && span->font->name
                        ? span->font->name
                        : "Span has no font name"
                        ;
                    FT_FaceRec *face = span->font->ft_face;
                    if (face && face->family_name) {
                        char *s;
                        char *n1 = face->family_name;
                        size_t l1 = strlen (n1);
                        size_t l2 = strlen (n2);

                        if (l1 != l2 || memcmp (n1, n2, l1)) {
                            s = malloc (l1 + l2 + 2);
                            if (s) {
                                memcpy (s, n2, l2);
                                s[l2] = '=';
                                memcpy (s + l2 + 1, n1, l1 + 1);
                                str_v = caml_copy_string (s);
                                free (s);
                            }
                        }
                    }
                    if (str_v == 0) {
                        str_v = caml_copy_string (n2);
                    }
                    ret_v = caml_alloc_small (1, 2);
                    Field (ret_v, 0) = str_v;
                    goto unlock;
                }
            }
        }
    }
 unlock:
    unlock ("ml_whatsunder");

 done:
    CAMLreturn (ret_v);
}

CAMLprim value ml_seltext (value ptr_v, value rect_v)
{
    CAMLparam2 (ptr_v, rect_v);
    fz_bbox *b;
    struct page *page;
    fz_text_span *span;
    struct mark first, last;
    int i, x0, x1, y0, y1;
    struct pagedim *pdim;
    char *s = String_val (ptr_v);

    if (trylock ("ml_seltext")) {
        goto done;
    }

    page = parse_pointer ("ml_seltext", s);
    ensuretext (page);

    pdim = &state.pagedims[page->pdimno];

    x0 = Int_val (Field (rect_v, 0)) + pdim->bounds.x0;
    y0 = Int_val (Field (rect_v, 1)) + pdim->bounds.y0;
    x1 = Int_val (Field (rect_v, 2)) + pdim->bounds.x0;
    y1 = Int_val (Field (rect_v, 3)) + pdim->bounds.y0;

    if (0) {
        glPolygonMode (GL_FRONT_AND_BACK, GL_LINE);
        glColor3ub (128, 128, 128);
        glRecti (x0, y0, x1, y1);
        glPolygonMode (GL_FRONT_AND_BACK, GL_FILL);
    }

    first.span = NULL;
    last.span = NULL;

    last.i = first.i = 0;
    first.span = page->text;
    for (span = page->text; span; span = span->next) {
        for (i = 0; i < span->len; ++i) {
            b = &span->text[i].bbox;
            int selected = 0;

            if (x0 >= b->x0 && x0 <= b->x1 && y0 >= b->y0 && y0 <= b->y1) {
                first.i = i;
                first.span = span;
                selected = 1;
            }
            if (x1 >= b->x0 && x1 <= b->x1 && y1 >= b->y0 && y1 <= b->y1) {
                last.i = i;
                last.span = span;
                selected = 1;
            }
            if (0 && selected) {
                glPolygonMode (GL_FRONT_AND_BACK, GL_LINE);
                glColor3ub (128, 128, 128);
                glRecti (b->x0, b->y0, b->x1, b->y1);
                glPolygonMode (GL_FRONT_AND_BACK, GL_FILL);
            }
        }
    }

    if (y1 < y0 || x1 < x0) {
        int swap = 0;

        if (first.span == last.span)  {
            swap = 1;
        }
        else {
            if (y1 < y0) {
                for (span = first.span; span && span != last.span;
                     span = span->next) {
                    if (span->eol) {
                        swap = 1;
                        break;
                    }
                }
            }
        }

        if (swap) {
            i = first.i;
            span = first.span;
            first.i = last.i;
            first.span = last.span;
            last.i = i;
            last.span = span;
        }
    }

    page->fmark = first;
    page->lmark = last;

    unlock ("ml_seltext");

 done:
    CAMLreturn (Val_unit);
}

static int pipespan (FILE *f, fz_text_span *span, int a, int b)
{
    char buf[4];
    int i, len, ret;

    for (i = a; i <= b; ++i) {
        len = runetochar (buf, &span->text[i].c);
        ret = fwrite (buf, len, 1, f);

        if (ret != 1) {
            printd (state.sock, "msg failed to write %d bytes ret=%d: %s",
                    len, ret, strerror (errno));
            return -1;
        }
    }
    return 0;
}

CAMLprim value ml_copysel (value ptr_v)
{
    CAMLparam1 (ptr_v);
    FILE *f;
    struct page *page;
    char *s = String_val (ptr_v);

    if (trylock ("ml_copysel")) {
        goto done;
    }

    if (!*s)  {
    close:
#ifdef USE_XSEL
        if (state.xselpipe) {
            int ret = pclose (state.xselpipe);
            if (ret)  {
                printd (state.sock, "msg failed to close xsel pipe `%s'",
                        strerror (errno));
            }
            state.xselpipe = NULL;
        }
#else
        printf ("========================================\n");
#endif
    }
    else {
        fz_text_span *span;

        page = parse_pointer ("ml_sopysel", s);

        if (!page->fmark.span || !page->lmark.span) {
            printd (state.sock, "msg nothing to copy");
            goto unlock;
        }

        f = stdout;
#ifdef USE_XSEL
        if (!state.xselpipe) {
            state.xselpipe = popen ("xsel -i", "w");
            if (!state.xselpipe) {
                printd (state.sock, "msg failed to open xsel pipe `%s'",
                        strerror (errno));
            }
            else {
                f = state.xselpipe;
            }
        }
        else  {
            f = state.xselpipe;
        }
#endif

        for (span = page->fmark.span;
             span && span != page->lmark.span->next;
             span = span->next) {
            int a = span == page->fmark.span ? page->fmark.i : 0;
            int b = span == page->lmark.span ? page->lmark.i : span->len - 1;
            if (pipespan (f, span, a, b))  {
                goto close;
            }
            if (span->eol)  {
                if (putc ('\n', f) == EOF) {
                    printd (state.sock,
                            "msg failed break line on xsel pipe `%s'",
                            strerror (errno));
                    goto close;
                }
            }
        }
        page->lmark.span = NULL;
        page->fmark.span = NULL;
    }

 unlock:
    unlock ("ml_copysel");

 done:
    CAMLreturn (Val_unit);
}

CAMLprim value ml_getpdimrect (value pagedimno_v)
{
    CAMLparam1 (pagedimno_v);
    CAMLlocal1 (ret_v);
    int pagedimno = Int_val (pagedimno_v);
    fz_rect box;

    ret_v = caml_alloc_small (4 * Double_wosize, Double_array_tag);
    if (trylock ("ml_getpdimrect")) {
        box = fz_empty_rect;
    }
    else {
        box = state.pagedims[pagedimno].mediabox;
        unlock ("ml_getpdimrect");
    }

    Store_double_field (ret_v, 0, box.x0);
    Store_double_field (ret_v, 1, box.x1);
    Store_double_field (ret_v, 2, box.y0);
    Store_double_field (ret_v, 3, box.y1);

    CAMLreturn (ret_v);
}

static double getmaxw (void)
{
    int i;
    struct pagedim *p;
    double maxw = 0.0;

    for (i = 0, p = state.pagedims; i < state.pagedimcount; ++i, ++p) {
        double x0, x1, w;

        x0 = MIN (p->mediabox.x0, p->mediabox.x1);
        x1 = MAX (p->mediabox.x0, p->mediabox.x1);

        w = x1 - x0;
        maxw = MAX (w, maxw);
    }
    return maxw;
}

CAMLprim value ml_getmaxw (value unit_v)
{
    CAMLparam1 (unit_v);
    CAMLlocal1 (ret_v);
    double maxw = 0.0;

    if (trylock ("ml_getmaxw")) {
        goto done;
    }
    maxw = getmaxw ();
    unlock ("ml_getmaxw");
 done:
    ret_v = caml_copy_double (maxw);
    CAMLreturn (ret_v);
}

CAMLprim value ml_zoom_for_height (value winw_v, value winh_v, value dw_v)
{
    CAMLparam3 (winw_v, winh_v, dw_v);
    CAMLlocal1 (ret_v);
    int i;
    double zoom = 1.0;
    double maxw = 0.0, maxh = 0.0;
    struct pagedim *p;
    double winw = Int_val (winw_v);
    double winh = Int_val (winh_v);
    double dw = Int_val (dw_v);
    double pw = 1.0, ph = 1.0, num, den;

    if (trylock ("ml_zoom_for_height")) {
        goto done;
    }

    if (state.proportional) {
        maxw = getmaxw ();
    }

    for (i = 0, p = state.pagedims; i < state.pagedimcount; ++i, ++p) {
        double x0, x1, y0, y1, w, h, scaledh, scale;

        x0 = MIN (p->mediabox.x0, p->mediabox.x1);
        x1 = MAX (p->mediabox.x0, p->mediabox.x1);
        y0 = MIN (p->mediabox.y0, p->mediabox.y1);
        y1 = MAX (p->mediabox.y0, p->mediabox.y1);

        w = x1 - x0;
        h = y1 - y0;

        if (state.proportional) {
            scale = w / maxw;
            scaledh = h * scale;
        }
        else  {
            scale = 1.0;
            scaledh = h;
        }

        if (scaledh > maxh) {
            maxh = scaledh;
            ph = scaledh;
            pw = w * scale;
        }
    }

    num = (winh * pw) + (ph * dw);
    den = ph * winw;
    zoom = num / den;

    unlock ("ml_zoom_for_height");
 done:
    ret_v = caml_copy_double (zoom);
    CAMLreturn (ret_v);
}

#include "glfont.c"

CAMLprim value ml_draw_string (value pt_v, value x_v, value y_v, value string_v)
{
    CAMLparam4 (pt_v, x_v, y_v, string_v);
    CAMLlocal1 (ret_v);
    int pt = Int_val(pt_v);
    int x = Int_val (x_v);
    int y = Int_val (y_v);
    double w;

    w = draw_string (state.face, pt, x, y, String_val (string_v));
    ret_v = caml_copy_double (w);
    CAMLreturn (ret_v);
}

CAMLprim value ml_measure_string (value pt_v, value string_v)
{
    CAMLparam2 (pt_v, string_v);
    CAMLlocal1 (ret_v);
    int pt = Int_val (pt_v);
    double w;

    w = measure_string (state.face, pt, String_val (string_v));
    ret_v = caml_copy_double (w);
    CAMLreturn (ret_v);
}

CAMLprim value ml_getpagebox (value opaque_v)
{
    CAMLparam1 (opaque_v);
    CAMLlocal1 (ret_v);
    fz_bbox bbox;
    fz_device *dev;
    char *s = String_val (opaque_v);
    struct page *page = parse_pointer ("ml_getpagebox", s);

    ret_v = caml_alloc_tuple (4);
    dev = fz_new_bbox_device (state.ctx, &bbox);
    dev->hints |= FZ_IGNORE_SHADE;
    pdf_run_page (state.doc, page->drawpage, dev, pagectm (page), NULL);
    fz_free_device (dev);

    Field (ret_v, 0) = Val_int (bbox.x0);
    Field (ret_v, 1) = Val_int (bbox.y0);
    Field (ret_v, 2) = Val_int (bbox.x1);
    Field (ret_v, 3) = Val_int (bbox.y1);

    CAMLreturn (ret_v);
}

CAMLprim value ml_setaalevel (value level_v)
{
    CAMLparam1 (level_v);

    state.aalevel = Int_val (level_v);
    CAMLreturn (Val_unit);
}

#if !defined _WIN32 && !defined __APPLE__
#undef pixel
#include <X11/X.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <GL/glx.h>

static void set_wm_class (int hack)
{
    if (hack) {
        Display *dpy;
        Window win;
        XClassHint hint;
        char *display;

        display = getenv ("DISPLAY");
        dpy = XOpenDisplay (display);
        if (!dpy) {
            fprintf (stderr, "XOpenDisplay `%s' failed\n",
                     display ? display : "null");
            return;
        }
        hint.res_name = "llpp";
        hint.res_class = "llpp";
        win = glXGetCurrentDrawable ();
        if (win == None) {
            fprintf (stderr, "glXGetCurrentDrawable returned None\n");
            XCloseDisplay (dpy);
            return;
        }
        XSetClassHint (dpy, win, &hint);
        XCloseDisplay (dpy);
    }
}
#else
#define set_wm_class(h) (void) (h)
#endif

enum { piunknown, pilinux, piwindows, piosx,
       pisun, pifreebsd, pidragonflybsd,
       piopenbsd, pimingw, picygwin };

CAMLprim value ml_platform (value unit_v)
{
    CAMLparam1 (unit_v);
    int platid = piunknown;

#if defined __linux__
    platid = pilinux;
#elif defined __CYGWIN__
    platid = picygwin;
#elif defined __MINGW32__
    platid = pimingw;
#elif defined _WIN32
    platid = piwindows;
#elif defined __DragonFly__
    platid = pidragonflybsd;
#elif defined __FreeBSD__
    platid = pifreebsd;
#elif defined __OpenBSD__
    platid = piopenbsd;
#elif defined __sun__
    platid = pisun;
#elif defined __APPLE__
    platid = piosx;
#endif
    CAMLreturn (Val_int (platid));
}

CAMLprim value ml_init (value sock_v, value params_v)
{
    CAMLparam2 (sock_v, params_v);
    CAMLlocal2 (trim_v, fuzz_v);
#ifndef _WIN32
    int ret;
#endif
    char *fontpath;
    int texcount;
    int wmclasshack;
    int colorspace;
    int mumemlimit;

    state.rotate = Int_val (Field (params_v, 0));
    state.proportional = Bool_val (Field (params_v, 1));
    trim_v = Field (params_v, 2);
    texcount = Int_val (Field (params_v, 3));
    state.sliceheight = Int_val (Field (params_v, 4));
    mumemlimit = Int_val (Field (params_v, 5));
    state.ctx = fz_new_context (&fz_alloc_default, mumemlimit);
    colorspace = Int_val (Field (params_v, 6));
    wmclasshack = Bool_val (Field (params_v, 7));
    fontpath = String_val (Field (params_v, 8));

    state.trimmargins = Bool_val (Field (trim_v, 0));
    fuzz_v = Field (trim_v, 1);
    state.trimfuzz.x0 = Int_val (Field (fuzz_v, 0));
    state.trimfuzz.y0 = Int_val (Field (fuzz_v, 1));
    state.trimfuzz.x1 = Int_val (Field (fuzz_v, 2));
    state.trimfuzz.y1 = Int_val (Field (fuzz_v, 3));

    set_tex_params (colorspace);
    set_wm_class (wmclasshack);

    if (*fontpath) {
        state.face = load_font (fontpath);
    }
    else {
        unsigned int len;
        void *base = pdf_find_substitute_font (0, 0, 0, 0, &len);

        state.face = load_builtin_font (base, len);
    }
    if (!state.face) _exit (1);

    fz_accelerate ();
    realloctexts (texcount);

#ifdef _WIN32
    state.sock = Socket_val (sock_v);
    InitializeCriticalSection (&critsec);
    state.thread = CreateThread (NULL, 0, mainloop, NULL, 0, NULL);
    if (state.thread == INVALID_HANDLE_VALUE) {
        errx (1, "CreateThread failed: %lx", GetLastError ());
    }
#else
    state.sock = Int_val (sock_v);
    ret = pthread_create (&state.thread, NULL, mainloop, NULL);
    if (ret) {
        errx (1, "pthread_create: %s", strerror (ret));
    }
#endif

    CAMLreturn (Val_unit);
}