[fontconfig.git] / src / fccache.c

/*
 * $RCSId: xc/lib/fontconfig/src/fccache.c,v 1.12 2002/08/22 07:36:44 keithp Exp $
 *
 * Copyright © 2000 Keith Packard
 * Copyright © 2005 Patrick Lam
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of Keith Packard not be used in
 * advertising or publicity pertaining to distribution of the software without
 * specific, written prior permission.  Keith Packard makes no
 * representations about the suitability of this software for any purpose.  It
 * is provided "as is" without express or implied warranty.
 *
 * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#include "fcint.h"
#include "../fc-arch/fcarch.h"
#include <stdio.h>
#include <fcntl.h>
#include <dirent.h>
#include <string.h>
#include <sys/types.h>
#if defined(HAVE_MMAP) || defined(__CYGWIN__)
#  include <unistd.h>
#  include <sys/mman.h>
#elif defined(_WIN32)
#  include <windows.h>
#endif

#define ENDIAN_TEST 0x12345678
#define MACHINE_SIGNATURE_SIZE (9 + 5*20 + 1)
/* for when we don't have sysconf: */
#define FC_HARDCODED_PAGESIZE 8192 

#ifndef O_BINARY
#define O_BINARY 0
#endif

static FILE *
FcDirCacheOpen (FcConfig *config, const FcChar8 *dir, FcChar8 **cache_path);

static void *
FcDirCacheProduce (FcFontSet *set, FcCache * metadata);

static off_t
FcCacheNextOffset(off_t w);

static FcBool
FcCacheHaveBank (int bank);

static void
FcCacheAddBankDir (int bank, const char * dir);

struct MD5Context {
        FcChar32 buf[4];
        FcChar32 bits[2];
        unsigned char in[64];
};

static void MD5Init(struct MD5Context *ctx);
static void MD5Update(struct MD5Context *ctx, unsigned char *buf, unsigned len);
static void MD5Final(unsigned char digest[16], struct MD5Context *ctx);
static void MD5Transform(FcChar32 buf[4], FcChar32 in[16]);

#define FC_DBG_CACHE_REF    1024

static char *
FcCacheReadString (FILE *file, char *dest, int len)
{
    int     c;
    char    *d = dest;

    if (len == 0)
        return 0;

    while ((c = getc (file)) != EOF && len > 0) {
        *d++ = c;
        if (c == '\0')
            return dest;
        len--;
    }
    return 0;
}

static FcBool
FcCacheWriteString (int fd, const char *chars)
{
    if (write (fd, chars, strlen(chars)+1) != strlen(chars)+1)
        return FcFalse;
    return FcTrue;
}

/* 
 * Find the next presumably-mmapable offset after the supplied file
 * position.
 */
static off_t
FcCacheNextOffset(off_t w)
{
    static long pagesize = -1;

    if (w == -1)
        return w;

    if (pagesize == -1)
#if defined (HAVE_SYSCONF)
        pagesize = sysconf(_SC_PAGESIZE);
#else
        pagesize = FC_HARDCODED_PAGESIZE;
#endif
    if (w % pagesize == 0) 
        return w;
    else
        return ((w / pagesize)+1)*pagesize;
}

/* Does not check that the cache has the appropriate arch section. */
FcBool
FcDirCacheValid (const FcChar8 *dir, FcConfig *config)
{
    FILE *file;

    file = FcDirCacheOpen (config, dir, NULL);

    if (file == NULL)
        return FcFalse;
    fclose (file);

    return FcTrue;
}

#define CACHEBASE_LEN (1 + 32 + 1 + sizeof (FC_ARCHITECTURE) + sizeof (FC_CACHE_SUFFIX))

static const char bin2hex[] = { '0', '1', '2', '3',
                                '4', '5', '6', '7',
                                '8', '9', 'a', 'b',
                                'c', 'd', 'e', 'f' };

static FcChar8 *
FcDirCacheBasename (const FcChar8 * dir, FcChar8 cache_base[CACHEBASE_LEN])
{
    unsigned char       hash[16];
    FcChar8             *hex_hash;
    int                 cnt;
    struct MD5Context   ctx;

    MD5Init (&ctx);
    MD5Update (&ctx, (unsigned char *)dir, strlen ((char *) dir));

    MD5Final (hash, &ctx);

    cache_base[0] = '/';
    hex_hash = cache_base + 1;
    for (cnt = 0; cnt < 16; ++cnt)
    {
        hex_hash[2*cnt  ] = bin2hex[hash[cnt] >> 4];
        hex_hash[2*cnt+1] = bin2hex[hash[cnt] & 0xf];
    }
    hex_hash[2*cnt] = 0;
    strcat ((char *) cache_base, "-" FC_ARCHITECTURE FC_CACHE_SUFFIX);

    return cache_base;
}

FcBool
FcDirCacheUnlink (const FcChar8 *dir, FcConfig *config)
{
    FcChar8     *cache_hashed = NULL;
    FcChar8     cache_base[CACHEBASE_LEN];
    FcStrList   *list;
    FcChar8     *cache_dir;

    FcDirCacheBasename (dir, cache_base);

    list = FcStrListCreate (config->cacheDirs);
    if (!list)
        return FcFalse;
        
    while ((cache_dir = FcStrListNext (list)))
    {
        cache_hashed = FcStrPlus (cache_dir, cache_base);
        if (!cache_hashed)
            break;
        (void) unlink ((char *) cache_hashed);
    }
    FcStrListDone (list);
    /* return FcFalse if something went wrong */
    if (cache_dir)
        return FcFalse;
    return FcTrue;
}

static int
FcCacheReadDirs (FcConfig * config,
                 FcStrList *list, FcFontSet * set, FcStrSet *processed_dirs)
{
    int                 ret = 0;
    FcChar8             *dir;
    FcStrSet            *subdirs;
    FcStrList           *sublist;

    /*
     * Read in the results from 'list'.
     */
    while ((dir = FcStrListNext (list)))
    {
        if (!FcConfigAcceptFilename (config, dir))
            continue;

        /* Skip this directory if already updated
         * to avoid the looped directories via symlinks
         * Clearly a dir not in fonts.conf shouldn't be globally cached.
         */

        if (FcStrSetMember (processed_dirs, dir))
            continue;
        if (!FcStrSetAdd (processed_dirs, dir))
            continue;

        subdirs = FcStrSetCreate ();
        if (!subdirs)
        {
            fprintf (stderr, "Can't create directory set\n");
            ret++;
            continue;
        }
        
        FcDirScanConfig (set, subdirs,
                         config->blanks, dir, FcFalse, config);
        
        sublist = FcStrListCreate (subdirs);
        FcStrSetDestroy (subdirs);
        if (!sublist)
        {
            fprintf (stderr, "Can't create subdir list in \"%s\"\n", dir);
            ret++;
            continue;
        }
        ret += FcCacheReadDirs (config, sublist, set, processed_dirs);
    }
    FcStrListDone (list);
    return ret;
}

FcFontSet *
FcCacheRead (FcConfig *config)
{
    FcFontSet   *s = FcFontSetCreate();
    FcStrSet    *processed_dirs;

    if (!s) 
        return 0;

    processed_dirs = FcStrSetCreate();
    if (!processed_dirs)
        goto bail;

    if (FcCacheReadDirs (config, FcConfigGetConfigDirs (config), s, processed_dirs))
        goto bail1;

    FcStrSetDestroy (processed_dirs);
    return s;

 bail1:
    FcStrSetDestroy (processed_dirs);
 bail:
    FcFontSetDestroy (s);
    return 0;
}

/* Opens the cache file for 'dir' for reading.
 * This searches the list of cache dirs for the relevant cache file,
 * returning the first one found.
 */
static FILE *
FcDirCacheOpen (FcConfig *config, const FcChar8 *dir, FcChar8 **cache_path)
{
    FILE        *file = NULL;
    FcChar8     *cache_hashed = NULL;
    FcChar8     cache_base[CACHEBASE_LEN];
    FcStrList   *list;
    FcChar8     *cache_dir;
    struct stat file_stat, dir_stat;

    if (stat ((char *) dir, &dir_stat) < 0)
        return NULL;

    FcDirCacheBasename (dir, cache_base);

    list = FcStrListCreate (config->cacheDirs);
    if (!list)
        return NULL;
        
    while ((cache_dir = FcStrListNext (list)))
    {
        cache_hashed = FcStrPlus (cache_dir, cache_base);
        if (!cache_hashed)
            break;
        file = fopen((char *) cache_hashed, "rb");
        if (file != NULL) {
            if (fstat (fileno (file), &file_stat) >= 0 &&
                dir_stat.st_mtime <= file_stat.st_mtime)
            {
                break;
            }
            fclose (file);
            file = NULL;
        }
        FcStrFree (cache_hashed);
        cache_hashed = NULL;
    }
    FcStrListDone (list);

    if (file == NULL)
        return NULL;
    
    if (cache_path)
        *cache_path = cache_hashed;
    else
        FcStrFree (cache_hashed);

    return file;
}

/* read serialized state from the cache file */
FcBool
FcDirCacheConsume (FILE *file, FcFontSet *set, FcStrSet *dirs,
                   const FcChar8 *dir, char *dirname)
{
    FcCache     metadata;
    void        *current_dir_block;
    char        subdir_name[FC_MAX_FILE_LEN + 1 + 12 + 1];
    int         i;

    if (fread(&metadata, sizeof(FcCache), 1, file) != 1)
        goto bail;
    if (metadata.magic != FC_CACHE_MAGIC)
        goto bail;

    /* skip directory name; it's just for fc-cat */
    if (!FcCacheReadString (file, subdir_name, sizeof (subdir_name)))
        goto bail;
    
    if (dirname)
        strcpy (dirname, subdir_name);

    for (i = 0; i < metadata.subdirs; i++) {
        if (!FcCacheReadString (file, subdir_name, sizeof (subdir_name)))
            goto bail;
        FcStrSetAdd (dirs, (FcChar8 *)subdir_name);
    }

    if (metadata.count)
    {
        int     fd = fileno (file);
#if defined(HAVE_MMAP) || defined(__CYGWIN__)
        current_dir_block = mmap (0, metadata.count, 
                                  PROT_READ, MAP_SHARED, fd, metadata.pos);
        if (current_dir_block == MAP_FAILED)
            goto bail;
#elif defined(_WIN32)
        {
            HANDLE hFileMap;

            hFileMap = CreateFileMapping((HANDLE) _get_osfhandle(fd), NULL, PAGE_READONLY, 0, 0, NULL);
            if (hFileMap == NULL)
                goto bail;

            current_dir_block = MapViewOfFile (hFileMap, FILE_MAP_READ, 0, metadata.pos, metadata.count);
            if (current_dir_block == NULL)
            {
                CloseHandle (hFileMap);
                goto bail;
            }
        }
#else
        if (lseek (fd, metatdata.pos, SEEK_SET) == -1)
            goto bail;

        current_dir_block = malloc (metadata.count);
        if (!current_dir_block)
            goto bail;

        /* could also use CreateMappedViewOfFile under MinGW... */
        if (read (fd, current_dir_block, metadata.count) != metadata.count)
        {
            free (current_dir_block);
            goto bail;
        }
#endif
        FcCacheAddBankDir (metadata.bank, (char *) dir);
        if (!FcFontSetUnserialize (&metadata, set, current_dir_block))
            goto bail;
    }

    return FcTrue;

 bail:
    return FcFalse;
}

FcBool
FcDirCacheRead (FcFontSet * set, FcStrSet * dirs, 
                const FcChar8 *dir, FcConfig *config)
{
    FILE    *file;

    file = FcDirCacheOpen (config, dir, NULL);
    if (file == NULL)
        goto bail;

    if (!FcDirCacheConsume (file, set, dirs, dir, NULL))
        goto bail1;

    if (config)
        FcConfigAddFontDir (config, (FcChar8 *)dir);
    
    fclose (file);
    return FcTrue;

bail1:
    fclose (file);
bail:
    return FcFalse;
}
    

static void *
FcDirCacheProduce (FcFontSet *set, FcCache *metadata)
{
    void * current_dir_block, * final_dir_block;
    static unsigned int rand_state = 0;
    int bank, needed_bytes_no_align;

#if defined (HAVE_RAND_R)
    if (!rand_state) 
        rand_state = time(0L);
    bank = rand_r(&rand_state);

    while (FcCacheHaveBank(bank))
        bank = rand_r(&rand_state);
#else
    if (!rand_state)
    {
        rand_state = 1;
        srand (time (0L));
    }
    bank = rand();

    while (FcCacheHaveBank(bank))
        bank = rand();
#endif

    memset (metadata, 0, sizeof(FcCache));
    FcFontSetNewBank();
    needed_bytes_no_align = FcFontSetNeededBytes (set);
    metadata->count = needed_bytes_no_align + 
        FcFontSetNeededBytesAlign ();
    metadata->magic = FC_CACHE_MAGIC;
    metadata->bank = bank;

    if (!needed_bytes_no_align) /* not a failure, no fonts to write */
    {
        /* no, you don't really need to write any bytes at all. */
        metadata->count = 0;
        return 0;
    }

    current_dir_block = malloc (metadata->count);
    if (!current_dir_block)
        goto bail;
    /* shut up valgrind */
    memset (current_dir_block, 0, metadata->count);
    final_dir_block = FcFontSetDistributeBytes (metadata, current_dir_block);

    if ((void *)((char *)current_dir_block+metadata->count) < final_dir_block)
        goto bail;
                              
    if (!FcFontSetSerialize (bank, set))
        goto bail;

    return current_dir_block;

 bail:
    free (current_dir_block);
    return 0;
}

static FcBool
FcMakeDirectory (const FcChar8 *dir)
{
    FcChar8 *parent;
    FcBool  ret;
    
    if (strlen ((char *) dir) == 0)
        return FcFalse;
    
    parent = FcStrDirname (dir);
    if (!parent)
        return FcFalse;
    if (access ((char *) parent, W_OK|X_OK) == 0)
        ret = mkdir ((char *) dir, 0777) == 0;
    else if (access ((char *) parent, F_OK) == -1)
        ret = FcMakeDirectory (parent) && (mkdir ((char *) dir, 0777) == 0);
    else
        ret = FcFalse;
    FcStrFree (parent);
    return ret;
}

/* write serialized state to the cache file */
FcBool
FcDirCacheWrite (FcFontSet *set, FcStrSet *dirs, const FcChar8 *dir, FcConfig *config)
{
    FcChar8         cache_base[CACHEBASE_LEN];
    FcChar8         *cache_hashed;
    int             fd, i;
    FcAtomic        *atomic;
    FcCache         metadata;
    void            *current_dir_block = 0;
    FcStrList       *list;
    FcChar8         *cache_dir = NULL;
    FcChar8         *test_dir;
    off_t           header_len;

    /*
     * Write it to the first directory in the list which is writable
     */
    
    list = FcStrListCreate (config->cacheDirs);
    if (!list)
        return FcFalse;
    while ((test_dir = FcStrListNext (list))) {
        if (access ((char *) test_dir, W_OK|X_OK) == 0)
        {
            cache_dir = test_dir;
            break;
        }
        else
        {
            /*
             * If the directory doesn't exist, try to create it
             */
            if (access ((char *) test_dir, F_OK) == -1) {
                if (FcMakeDirectory (test_dir))
                {
                    cache_dir = test_dir;
                    break;
                }
            }
        }
    }
    FcStrListDone (list);
    if (!cache_dir)
        return FcFalse;
    FcDirCacheBasename (dir, cache_base);
    cache_hashed = FcStrPlus (cache_dir, cache_base);
    if (!cache_hashed)
        return FcFalse;

    current_dir_block = FcDirCacheProduce (set, &metadata);

    if (metadata.count && !current_dir_block)
        goto bail1;

    if (FcDebug () & FC_DBG_CACHE)
        printf ("FcDirCacheWriteDir dir \"%s\" file \"%s\"\n",
                dir, cache_hashed);

    atomic = FcAtomicCreate ((FcChar8 *)cache_hashed);
    if (!atomic)
        goto bail1;

    if (!FcAtomicLock (atomic))
        goto bail2;

    fd = open((char *)FcAtomicNewFile (atomic), O_RDWR | O_CREAT | O_BINARY, 0666);
    if (fd == -1)
        goto bail3;
    
    /*
     * Compute file header length -- the FcCache followed by the subdir names
     */
    header_len = sizeof (FcCache);
    header_len += strlen ((char *) dir) + 1;
    for (i = 0; i < dirs->size; i++)
        header_len += strlen ((char *)dirs->strs[i]) + 1;
    
    metadata.pos = FcCacheNextOffset (lseek (fd, 0, SEEK_CUR) + header_len);
    metadata.subdirs = dirs->size;
    
    /*
     * Write out the header
     */
    if (write (fd, &metadata, sizeof(FcCache)) != sizeof(FcCache)) 
    {
        perror("write metadata");
        goto bail5;
    }
    
    FcCacheWriteString (fd, (char *) dir);
    
    for (i = 0; i < dirs->size; i++)
        FcCacheWriteString (fd, (char *)dirs->strs[i]);

    if (metadata.count)
    {
        if (lseek (fd, metadata.pos, SEEK_SET) != metadata.pos)
            perror("lseek");
        else if (write (fd, current_dir_block, metadata.count) !=
                 metadata.count)
            perror("write current_dir_block");
        free (current_dir_block);
        current_dir_block = 0;
    }

    close(fd);
    if (!FcAtomicReplaceOrig(atomic))
        goto bail3;
    FcStrFree ((FcChar8 *)cache_hashed);
    FcAtomicUnlock (atomic);
    FcAtomicDestroy (atomic);
    return FcTrue;

 bail5:
    close (fd);
 bail3:
    FcAtomicUnlock (atomic);
 bail2:
    FcAtomicDestroy (atomic);
 bail1:
    FcStrFree ((FcChar8 *)cache_hashed);
    if (current_dir_block)
        free (current_dir_block);
    return FcFalse;
}

static int banks_ptr = 0, banks_alloc = 0;
int * _fcBankId = 0, * _fcBankIdx = 0;
static const char ** bankDirs = 0;

static FcBool
FcCacheHaveBank (int bank)
{
    int i;

    if (bank < FC_BANK_FIRST)
        return FcTrue;

    for (i = 0; i < banks_ptr; i++)
        if (_fcBankId[i] == bank)
            return FcTrue;

    return FcFalse;
}

int
FcCacheBankToIndexMTF (int bank)
{
    int i, j;

    for (i = 0; i < banks_ptr; i++)
        if (_fcBankId[_fcBankIdx[i]] == bank)
        {
            int t = _fcBankIdx[i];

            for (j = i; j > 0; j--)
                _fcBankIdx[j] = _fcBankIdx[j-1];
            _fcBankIdx[0] = t;
            return t;
        }

    if (banks_ptr >= banks_alloc)
    {
        int * b, * bidx;
        const char ** bds;

        b = realloc (_fcBankId, (banks_alloc + 4) * sizeof(int));
        if (!b)
            return -1;
        _fcBankId = b;

        bidx = realloc (_fcBankIdx, (banks_alloc + 4) * sizeof(int));
        if (!bidx)
            return -1;
        _fcBankIdx = bidx;

        bds = realloc (bankDirs, (banks_alloc + 4) * sizeof (char *));
        if (!bds)
            return -1;
        bankDirs = bds;

        banks_alloc += 4;
    }

    i = banks_ptr++;
    _fcBankId[i] = bank;
    _fcBankIdx[i] = i;
    return i;
}

static void
FcCacheAddBankDir (int bank, const char * dir)
{
    int bi = FcCacheBankToIndexMTF (bank);

    if (bi < 0)
        return;

    bankDirs[bi] = (const char *)FcStrCopy ((FcChar8 *)dir);
}

const char *
FcCacheFindBankDir (int bank)
{
    int bi = FcCacheBankToIndex (bank);
    return bankDirs[bi];
}

/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD5Context structure, pass it to MD5Init, call MD5Update as
 * needed on buffers full of bytes, and then call MD5Final, which
 * will fill a supplied 16-byte array with the digest.
 */

#ifndef HIGHFIRST
#define byteReverse(buf, len)   /* Nothing */
#else
/*
 * Note: this code is harmless on little-endian machines.
 */
void byteReverse(unsigned char *buf, unsigned longs)
{
    FcChar32 t;
    do {
        t = (FcChar32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
            ((unsigned) buf[1] << 8 | buf[0]);
        *(FcChar32 *) buf = t;
        buf += 4;
    } while (--longs);
}
#endif

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
static void MD5Init(struct MD5Context *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bits[0] = 0;
    ctx->bits[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void MD5Update(struct MD5Context *ctx, unsigned char *buf, unsigned len)
{
    FcChar32 t;

    /* Update bitcount */

    t = ctx->bits[0];
    if ((ctx->bits[0] = t + ((FcChar32) len << 3)) < t)
        ctx->bits[1]++;         /* Carry from low to high */
    ctx->bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */

    /* Handle any leading odd-sized chunks */

    if (t) {
        unsigned char *p = (unsigned char *) ctx->in + t;

        t = 64 - t;
        if (len < t) {
            memcpy(p, buf, len);
            return;
        }
        memcpy(p, buf, t);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (FcChar32 *) ctx->in);
        buf += t;
        len -= t;
    }
    /* Process data in 64-byte chunks */

    while (len >= 64) {
        memcpy(ctx->in, buf, 64);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (FcChar32 *) ctx->in);
        buf += 64;
        len -= 64;
    }

    /* Handle any remaining bytes of data. */

    memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
{
    unsigned count;
    unsigned char *p;

    /* Compute number of bytes mod 64 */
    count = (ctx->bits[0] >> 3) & 0x3F;

    /* Set the first char of padding to 0x80.  This is safe since there is
       always at least one byte free */
    p = ctx->in + count;
    *p++ = 0x80;

    /* Bytes of padding needed to make 64 bytes */
    count = 64 - 1 - count;

    /* Pad out to 56 mod 64 */
    if (count < 8) {
        /* Two lots of padding:  Pad the first block to 64 bytes */
        memset(p, 0, count);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (FcChar32 *) ctx->in);

        /* Now fill the next block with 56 bytes */
        memset(ctx->in, 0, 56);
    } else {
        /* Pad block to 56 bytes */
        memset(p, 0, count - 8);
    }
    byteReverse(ctx->in, 14);

    /* Append length in bits and transform */
    ((FcChar32 *) ctx->in)[14] = ctx->bits[0];
    ((FcChar32 *) ctx->in)[15] = ctx->bits[1];

    MD5Transform(ctx->buf, (FcChar32 *) ctx->in);
    byteReverse((unsigned char *) ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset(ctx, 0, sizeof(ctx));        /* In case it's sensitive */
}


/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
        ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void MD5Transform(FcChar32 buf[4], FcChar32 in[16])
{
    register FcChar32 a, b, c, d;

    a = buf[0];
    b = buf[1];
    c = buf[2];
    d = buf[3];

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}