/* This file is part of libmspack.
* (C) 2003-2018 Stuart Caie.
*
* libmspack is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License (LGPL) version 2.1
*
* For further details, see the file COPYING.LIB distributed with libmspack
*/
/* CHM decompression implementation */
#include <system.h>
#include <chm.h>
/* prototypes */
static struct mschmd_header * chmd_open(
struct mschm_decompressor *base, const char *filename);
static struct mschmd_header * chmd_fast_open(
struct mschm_decompressor *base, const char *filename);
static struct mschmd_header *chmd_real_open(
struct mschm_decompressor *base, const char *filename, int entire);
static void chmd_close(
struct mschm_decompressor *base, struct mschmd_header *chm);
static int chmd_read_headers(
struct mspack_system *sys, struct mspack_file *fh,
struct mschmd_header *chm, int entire);
static int chmd_fast_find(
struct mschm_decompressor *base, struct mschmd_header *chm,
const char *filename, struct mschmd_file *f_ptr, int f_size);
static unsigned char *read_chunk(
struct mschm_decompressor_p *self, struct mschmd_header *chm,
struct mspack_file *fh, unsigned int chunk);
static int search_chunk(
struct mschmd_header *chm, const unsigned char *chunk, const char *filename,
const unsigned char **result, const unsigned char **result_end);
static inline int compare(
const char *s1, const char *s2, int l1, int l2);
static int chmd_extract(
struct mschm_decompressor *base, struct mschmd_file *file,
const char *filename);
static int chmd_sys_write(
struct mspack_file *file, void *buffer, int bytes);
static int chmd_init_decomp(
struct mschm_decompressor_p *self, struct mschmd_file *file);
static int read_reset_table(
struct mschm_decompressor_p *self, struct mschmd_sec_mscompressed *sec,
unsigned int entry, off_t *length_ptr, off_t *offset_ptr);
static int read_spaninfo(
struct mschm_decompressor_p *self, struct mschmd_sec_mscompressed *sec,
off_t *length_ptr);
static int find_sys_file(
struct mschm_decompressor_p *self, struct mschmd_sec_mscompressed *sec,
struct mschmd_file **f_ptr, const char *name);
static unsigned char *read_sys_file(
struct mschm_decompressor_p *self, struct mschmd_file *file);
static int chmd_error(
struct mschm_decompressor *base);
static int read_off64(
off_t *var, unsigned char *mem, struct mspack_system *sys,
struct mspack_file *fh);
/* filenames of the system files used for decompression.
* Content and ControlData are essential.
* ResetTable is preferred, but SpanInfo can be used if not available
*/
static const char *content_name = "::DataSpace/Storage/MSCompressed/Content";
static const char *control_name = "::DataSpace/Storage/MSCompressed/ControlData";
static const char *spaninfo_name = "::DataSpace/Storage/MSCompressed/SpanInfo";
static const char *rtable_name = "::DataSpace/Storage/MSCompressed/Transform/"
"{7FC28940-9D31-11D0-9B27-00A0C91E9C7C}/InstanceData/ResetTable";
/***************************************
* MSPACK_CREATE_CHM_DECOMPRESSOR
***************************************
* constructor
*/
struct mschm_decompressor *
mspack_create_chm_decompressor(struct mspack_system *sys)
{
struct mschm_decompressor_p *self = NULL;
if (!sys) sys = mspack_default_system;
if (!mspack_valid_system(sys)) return NULL;
if ((self = (struct mschm_decompressor_p *) sys->alloc(sys, sizeof(struct mschm_decompressor_p)))) {
self->base.open = &chmd_open;
self->base.close = &chmd_close;
self->base.extract = &chmd_extract;
self->base.last_error = &chmd_error;
self->base.fast_open = &chmd_fast_open;
self->base.fast_find = &chmd_fast_find;
self->system = sys;
self->error = MSPACK_ERR_OK;
self->d = NULL;
}
return (struct mschm_decompressor *) self;
}
/***************************************
* MSPACK_DESTROY_CAB_DECOMPRESSOR
***************************************
* destructor
*/
void mspack_destroy_chm_decompressor(struct mschm_decompressor *base) {
struct mschm_decompressor_p *self = (struct mschm_decompressor_p *) base;
if (self) {
struct mspack_system *sys = self->system;
if (self->d) {
if (self->d->infh) sys->close(self->d->infh);
if (self->d->state) lzxd_free(self->d->state);
sys->free(self->d);
}
sys->free(self);
}
}
/***************************************
* CHMD_OPEN
***************************************
* opens a file and tries to read it as a CHM file.
* Calls chmd_real_open() with entire=1.
*/
static struct mschmd_header *chmd_open(struct mschm_decompressor *base,
const char *filename)
{
return chmd_real_open(base, filename, 1);
}
/***************************************
* CHMD_FAST_OPEN
***************************************
* opens a file and tries to read it as a CHM file, but does not read
* the file headers. Calls chmd_real_open() with entire=0
*/
static struct mschmd_header *chmd_fast_open(struct mschm_decompressor *base,
const char *filename)
{
return chmd_real_open(base, filename, 0);
}
/***************************************
* CHMD_REAL_OPEN
***************************************
* the real implementation of chmd_open() and chmd_fast_open(). It simply
* passes the "entire" parameter to chmd_read_headers(), which will then
* either read all headers, or a bare mininum.
*/
static struct mschmd_header *chmd_real_open(struct mschm_decompressor *base,
const char *filename, int entire)
{
struct mschm_decompressor_p *self = (struct mschm_decompressor_p *) base;
struct mschmd_header *chm = NULL;
struct mspack_system *sys;
struct mspack_file *fh;
int error;
if (!base) return NULL;
sys = self->system;
if ((fh = sys->open(sys, filename, MSPACK_SYS_OPEN_READ))) {
if ((chm = (struct mschmd_header *) sys->alloc(sys, sizeof(struct mschmd_header)))) {
chm->filename = filename;
error = chmd_read_headers(sys, fh, chm, entire);
if (error) {
/* if the error is DATAFORMAT, and there are some results, return
* partial results with a warning, rather than nothing */
if (error == MSPACK_ERR_DATAFORMAT && (chm->files || chm->sysfiles)) {
sys->message(fh, "WARNING; contents are corrupt");
error = MSPACK_ERR_OK;
}
else {
chmd_close(base, chm);
chm = NULL;
}
}
self->error = error;
}
else {
self->error = MSPACK_ERR_NOMEMORY;
}
sys->close(fh);
}
else {
self->error = MSPACK_ERR_OPEN;
}
return chm;
}
/***************************************
* CHMD_CLOSE
***************************************
* frees all memory associated with a given mschmd_header
*/
static void chmd_close(struct mschm_decompressor *base,
struct mschmd_header *chm)
{
struct mschm_decompressor_p *self = (struct mschm_decompressor_p *) base;
struct mschmd_file *fi, *nfi;
struct mspack_system *sys;
unsigned int i;
if (!base) return;
sys = self->system;
self->error = MSPACK_ERR_OK;
/* free files */
for (fi = chm->files; fi; fi = nfi) {
nfi = fi->next;
sys->free(fi);
}
for (fi = chm->sysfiles; fi; fi = nfi) {
nfi = fi->next;
sys->free(fi);
}
/* if this CHM was being decompressed, free decompression state */
if (self->d && (self->d->chm == chm)) {
if (self->d->infh) sys->close(self->d->infh);
if (self->d->state) lzxd_free(self->d->state);
sys->free(self->d);
self->d = NULL;
}
/* if this CHM had a chunk cache, free it and contents */
if (chm->chunk_cache) {
for (i = 0; i < chm->num_chunks; i++) sys->free(chm->chunk_cache[i]);
sys->free(chm->chunk_cache);
}
sys->free(chm);
}
/***************************************
* CHMD_READ_HEADERS
***************************************
* reads the basic CHM file headers. If the "entire" parameter is
* non-zero, all file entries will also be read. fills out a pre-existing
* mschmd_header structure, allocates memory for files as necessary
*/
/* The GUIDs found in CHM headers */
static const unsigned char guids[32] = {
/* {7C01FD10-7BAA-11D0-9E0C-00A0-C922-E6EC} */
0x10, 0xFD, 0x01, 0x7C, 0xAA, 0x7B, 0xD0, 0x11,
0x9E, 0x0C, 0x00, 0xA0, 0xC9, 0x22, 0xE6, 0xEC,
/* {7C01FD11-7BAA-11D0-9E0C-00A0-C922-E6EC} */
0x11, 0xFD, 0x01, 0x7C, 0xAA, 0x7B, 0xD0, 0x11,
0x9E, 0x0C, 0x00, 0xA0, 0xC9, 0x22, 0xE6, 0xEC
};
/* reads an encoded integer into a variable; 7 bits of data per byte,
* the high bit is used to indicate that there is another byte */
#define READ_ENCINT(var) do { \
(var) = 0; \
do { \
if (p >= end) goto chunk_end; \
(var) = ((var) << 7) | (*p & 0x7F); \
} while (*p++ & 0x80); \
} while (0)
static int chmd_read_headers(struct mspack_system *sys, struct mspack_file *fh,
struct mschmd_header *chm, int entire)
{
unsigned int section, name_len, x, errors, num_chunks;
unsigned char buf[0x54], *chunk = NULL, *name, *p, *end;
struct mschmd_file *fi, *link = NULL;
off_t offset, length;
int num_entries;
/* initialise pointers */
chm->files = NULL;
chm->sysfiles = NULL;
chm->chunk_cache = NULL;
chm->sec0.base.chm = chm;
chm->sec0.base.id = 0;
chm->sec1.base.chm = chm;
chm->sec1.base.id = 1;
chm->sec1.content = NULL;
chm->sec1.control = NULL;
chm->sec1.spaninfo = NULL;
chm->sec1.rtable = NULL;
/* read the first header */
if (sys->read(fh, &buf[0], chmhead_SIZEOF) != chmhead_SIZEOF) {
return MSPACK_ERR_READ;
}
/* check ITSF signature */
if (EndGetI32(&buf[chmhead_Signature]) != 0x46535449) {
return MSPACK_ERR_SIGNATURE;
}
/* check both header GUIDs */
if (memcmp(&buf[chmhead_GUID1], &guids[0], 32L) != 0) {
D(("incorrect GUIDs"))
return MSPACK_ERR_SIGNATURE;
}
chm->version = EndGetI32(&buf[chmhead_Version]);
chm->timestamp = EndGetM32(&buf[chmhead_Timestamp]);
chm->language = EndGetI32(&buf[chmhead_LanguageID]);
if (chm->version > 3) {
sys->message(fh, "WARNING; CHM version > 3");
}
/* read the header section table */
if (sys->read(fh, &buf[0], chmhst3_SIZEOF) != chmhst3_SIZEOF) {
return MSPACK_ERR_READ;
}
/* chmhst3_OffsetCS0 does not exist in version 1 or 2 CHM files.
* The offset will be corrected later, once HS1 is read.
*/
if (read_off64(&offset, &buf[chmhst_OffsetHS0], sys, fh) ||
read_off64(&chm->dir_offset, &buf[chmhst_OffsetHS1], sys, fh) ||
read_off64(&chm->sec0.offset, &buf[chmhst3_OffsetCS0], sys, fh))
{
return MSPACK_ERR_DATAFORMAT;
}
/* seek to header section 0 */
if (sys->seek(fh, offset, MSPACK_SYS_SEEK_START)) {
return MSPACK_ERR_SEEK;
}
/* read header section 0 */
if (sys->read(fh, &buf[0], chmhs0_SIZEOF) != chmhs0_SIZEOF) {
return MSPACK_ERR_READ;
}
if (read_off64(&chm->length, &buf[chmhs0_FileLen], sys, fh)) {
return MSPACK_ERR_DATAFORMAT;
}
/* seek to header section 1 */
if (sys->seek(fh, chm->dir_offset, MSPACK_SYS_SEEK_START)) {
return MSPACK_ERR_SEEK;
}
/* read header section 1 */
if (sys->read(fh, &buf[0], chmhs1_SIZEOF) != chmhs1_SIZEOF) {
return MSPACK_ERR_READ;
}
chm->dir_offset = sys->tell(fh);
chm->chunk_size = EndGetI32(&buf[chmhs1_ChunkSize]);
chm->density = EndGetI32(&buf[chmhs1_Density]);
chm->depth = EndGetI32(&buf[chmhs1_Depth]);
chm->index_root = EndGetI32(&buf[chmhs1_IndexRoot]);
chm->num_chunks = EndGetI32(&buf[chmhs1_NumChunks]);
chm->first_pmgl = EndGetI32(&buf[chmhs1_FirstPMGL]);
chm->last_pmgl = EndGetI32(&buf[chmhs1_LastPMGL]);
if (chm->version < 3) {
/* versions before 3 don't have chmhst3_OffsetCS0 */
chm->sec0.offset = chm->dir_offset + (chm->chunk_size * chm->num_chunks);
}
/* check if content offset or file size is wrong */
if (chm->sec0.offset > chm->length) {
D(("content section begins after file has ended"))
return MSPACK_ERR_DATAFORMAT;
}
/* ensure there are chunks and that chunk size is
* large enough for signature and num_entries */
if (chm->chunk_size < (pmgl_Entries + 2)) {
D(("chunk size not large enough"))
return MSPACK_ERR_DATAFORMAT;
}
if (chm->num_chunks == 0) {
D(("no chunks"))
return MSPACK_ERR_DATAFORMAT;
}
/* The chunk_cache data structure is not great; large values for num_chunks
* or num_chunks*chunk_size can exhaust all memory. Until a better chunk
* cache is implemented, put arbitrary limits on num_chunks and chunk size.
*/
if (chm->num_chunks > 100000) {
D(("more than 100,000 chunks"))
return MSPACK_ERR_DATAFORMAT;
}
if (chm->chunk_size > 8192) {
D(("chunk size over 8192 (get in touch if this is valid)"))
return MSPACK_ERR_DATAFORMAT;
}
if ((off_t)chm->chunk_size * (off_t)chm->num_chunks > chm->length) {
D(("chunks larger than entire file"))
return MSPACK_ERR_DATAFORMAT;
}
/* common sense checks on header section 1 fields */
if (chm->chunk_size != 4096) {
sys->message(fh, "WARNING; chunk size is not 4096");
}
if (chm->first_pmgl != 0) {
sys->message(fh, "WARNING; first PMGL chunk is not zero");
}
if (chm->first_pmgl > chm->last_pmgl) {
D(("first pmgl chunk is after last pmgl chunk"))
return MSPACK_ERR_DATAFORMAT;
}
if (chm->index_root != 0xFFFFFFFF && chm->index_root >= chm->num_chunks) {
D(("index_root outside valid range"))
return MSPACK_ERR_DATAFORMAT;
}
/* if we are doing a quick read, stop here! */
if (!entire) {
return MSPACK_ERR_OK;
}
/* seek to the first PMGL chunk, and reduce the number of chunks to read */
if ((x = chm->first_pmgl) != 0) {
if (sys->seek(fh,(off_t) (x * chm->chunk_size), MSPACK_SYS_SEEK_CUR)) {
return MSPACK_ERR_SEEK;
}
}
num_chunks = chm->last_pmgl - x + 1;
if (!(chunk = (unsigned char *) sys->alloc(sys, (size_t)chm->chunk_size))) {
return MSPACK_ERR_NOMEMORY;
}
/* read and process all chunks from FirstPMGL to LastPMGL */
errors = 0;
while (num_chunks--) {
/* read next chunk */
if (sys->read(fh, chunk, (int)chm->chunk_size) != (int)chm->chunk_size) {
sys->free(chunk);
return MSPACK_ERR_READ;
}
/* process only directory (PMGL) chunks */
if (EndGetI32(&chunk[pmgl_Signature]) != 0x4C474D50) continue;
if (EndGetI32(&chunk[pmgl_QuickRefSize]) < 2) {
sys->message(fh, "WARNING; PMGL quickref area is too small");
}
if (EndGetI32(&chunk[pmgl_QuickRefSize]) >
(chm->chunk_size - pmgl_Entries))
{
sys->message(fh, "WARNING; PMGL quickref area is too large");
}
p = &chunk[pmgl_Entries];
end = &chunk[chm->chunk_size - 2];
num_entries = EndGetI16(end);
while (num_entries--) {
READ_ENCINT(name_len);
if (name_len > (unsigned int) (end - p)) goto chunk_end;
name = p; p += name_len;
READ_ENCINT(section);
READ_ENCINT(offset);
READ_ENCINT(length);
/* ignore blank or one-char (e.g. "/") filenames we'd return as blank */
if (name_len < 2 || !name[0] || !name[1]) continue;
/* empty files and directory names are stored as a file entry at
* offset 0 with length 0. We want to keep empty files, but not
* directory names, which end with a "/" */
if ((offset == 0) && (length == 0)) {
if ((name_len > 0) && (name[name_len-1] == '/')) continue;
}
if (section > 1) {
sys->message(fh, "invalid section number '%u'.", section);
continue;
}
if (!(fi = (struct mschmd_file *) sys->alloc(sys, sizeof(struct mschmd_file) + name_len + 1))) {
sys->free(chunk);
return MSPACK_ERR_NOMEMORY;
}
fi->next = NULL;
fi->filename = (char *) &fi[1];
fi->section = ((section == 0) ? (struct mschmd_section *) (&chm->sec0)
: (struct mschmd_section *) (&chm->sec1));
fi->offset = offset;
fi->length = length;
sys->copy(name, fi->filename, (size_t) name_len);
fi->filename[name_len] = '\0';
if (name[0] == ':' && name[1] == ':') {
/* system file */
if (name_len == 40 && memcmp(name, content_name, 40) == 0) {
chm->sec1.content = fi;
}
else if (name_len == 44 && memcmp(name, control_name, 44) == 0) {
chm->sec1.control = fi;
}
else if (name_len == 41 && memcmp(name, spaninfo_name, 41) == 0) {
chm->sec1.spaninfo = fi;
}
else if (name_len == 105 && memcmp(name, rtable_name, 105) == 0) {
chm->sec1.rtable = fi;
}
fi->next = chm->sysfiles;
chm->sysfiles = fi;
}
else {
/* normal file */
if (link) link->next = fi; else chm->files = fi;
link = fi;
}
}
/* this is reached either when num_entries runs out, or if
* reading data from the chunk reached a premature end of chunk */
chunk_end:
if (num_entries >= 0) {
D(("chunk ended before all entries could be read"))
errors++;
}
}
sys->free(chunk);
return (errors > 0) ? MSPACK_ERR_DATAFORMAT : MSPACK_ERR_OK;
}
/***************************************
* CHMD_FAST_FIND
***************************************
* uses PMGI index chunks and quickref data to quickly locate a file
* directly from the on-disk index.
*
* TODO: protect against infinite loops in chunks (where pgml_NextChunk
* or a PMGI index entry point to an already visited chunk)
*/
static int chmd_fast_find(struct mschm_decompressor *base,
struct mschmd_header *chm, const char *filename,
struct mschmd_file *f_ptr, int f_size)
{
struct mschm_decompressor_p *self = (struct mschm_decompressor_p *) base;
struct mspack_system *sys;
struct mspack_file *fh;
/* p and end are initialised to prevent MSVC warning about "potentially"
* uninitialised usage. This is provably untrue, but MS won't fix:
* https://developercommunity.visualstudio.com/content/problem/363489/c4701-false-positive-warning.html */
const unsigned char *chunk, *p = NULL, *end = NULL;
int err = MSPACK_ERR_OK, result = -1;
unsigned int n, sec;
if (!self || !chm || !f_ptr || (f_size != sizeof(struct mschmd_file))) {
return MSPACK_ERR_ARGS;
}
sys = self->system;
/* clear the results structure */
memset(f_ptr, 0, f_size);
if (!(fh = sys->open(sys, chm->filename, MSPACK_SYS_OPEN_READ))) {
return MSPACK_ERR_OPEN;
}
/* go through PMGI chunk hierarchy to reach PMGL chunk */
if (chm->index_root < chm->num_chunks) {
n = chm->index_root;
for (;;) {
if (!(chunk = read_chunk(self, chm, fh, n))) {
sys->close(fh);
return self->error;
}
/* search PMGI/PMGL chunk. exit early if no entry found */
if ((result = search_chunk(chm, chunk, filename, &p, &end)) <= 0) {
break;
}
/* found result. loop around for next chunk if this is PMGI */
if (chunk[3] == 0x4C) break; else READ_ENCINT(n);
}
}
else {
/* PMGL chunks only, search from first_pmgl to last_pmgl */
for (n = chm->first_pmgl; n <= chm->last_pmgl;
n = EndGetI32(&chunk[pmgl_NextChunk]))
{
if (!(chunk = read_chunk(self, chm, fh, n))) {
err = self->error;
break;
}
/* search PMGL chunk. exit if file found */
if ((result = search_chunk(chm, chunk, filename, &p, &end)) > 0) {
break;
}
/* stop simple infinite loops: can't visit the same chunk twice */
if (n == EndGetI32(&chunk[pmgl_NextChunk])) {
break;
}
}
}
/* if we found a file, read it */
if (result > 0) {
READ_ENCINT(sec);
f_ptr->section = (sec == 0) ? (struct mschmd_section *) &chm->sec0
: (struct mschmd_section *) &chm->sec1;
READ_ENCINT(f_ptr->offset);
READ_ENCINT(f_ptr->length);
}
else if (result < 0) {
err = MSPACK_ERR_DATAFORMAT;
}
sys->close(fh);
return self->error = err;
chunk_end:
D(("read beyond end of chunk entries"))
sys->close(fh);
return self->error = MSPACK_ERR_DATAFORMAT;
}
/* reads the given chunk into memory, storing it in a chunk cache
* so it doesn't need to be read from disk more than once
*/
static unsigned char *read_chunk(struct mschm_decompressor_p *self,
struct mschmd_header *chm,
struct mspack_file *fh,
unsigned int chunk_num)
{
struct mspack_system *sys = self->system;
unsigned char *buf;
/* check arguments - most are already checked by chmd_fast_find */
if (chunk_num >= chm->num_chunks) return NULL;
/* ensure chunk cache is available */
if (!chm->chunk_cache) {
size_t size = sizeof(unsigned char *) * chm->num_chunks;
if (!(chm->chunk_cache = (unsigned char **) sys->alloc(sys, size))) {
self->error = MSPACK_ERR_NOMEMORY;
return NULL;
}
memset(chm->chunk_cache, 0, size);
}
/* try to answer out of chunk cache */
if (chm->chunk_cache[chunk_num]) return chm->chunk_cache[chunk_num];
/* need to read chunk - allocate memory for it */
if (!(buf = (unsigned char *) sys->alloc(sys, chm->chunk_size))) {
self->error = MSPACK_ERR_NOMEMORY;
return NULL;
}
/* seek to block and read it */
if (sys->seek(fh, (off_t) (chm->dir_offset + (chunk_num * chm->chunk_size)),
MSPACK_SYS_SEEK_START))
{
self->error = MSPACK_ERR_SEEK;
sys->free(buf);
return NULL;
}
if (sys->read(fh, buf, (int)chm->chunk_size) != (int)chm->chunk_size) {
self->error = MSPACK_ERR_READ;
sys->free(buf);
return NULL;
}
/* check the signature. Is is PMGL or PMGI? */
if (!((buf[0] == 0x50) && (buf[1] == 0x4D) && (buf[2] == 0x47) &&
((buf[3] == 0x4C) || (buf[3] == 0x49))))
{
self->error = MSPACK_ERR_SEEK;
sys->free(buf);
return NULL;
}
/* all OK. Store chunk in cache and return it */
return chm->chunk_cache[chunk_num] = buf;
}
/* searches a PMGI/PMGL chunk for a given filename entry. Returns -1 on
* data format error, 0 if entry definitely not found, 1 if entry
* found. In the latter case, *result and *result_end are set pointing
* to that entry's data (either the "next chunk" ENCINT for a PMGI or
* the section, offset and length ENCINTs for a PMGL).
*
* In the case of PMGL chunks, the entry has definitely been
* found. In the case of PMGI chunks, the entry which points to the
* chunk that may eventually contain that entry has been found.
*/
static int search_chunk(struct mschmd_header *chm,
const unsigned char *chunk,
const char *filename,
const unsigned char **result,
const unsigned char **result_end)
{
const unsigned char *start, *end, *p;
unsigned int qr_size, num_entries, qr_entries, qr_density, name_len;
unsigned int L, R, M, fname_len, entries_off, is_pmgl;
int cmp;
fname_len = strlen(filename);
/* PMGL chunk or PMGI chunk? (note: read_chunk() has already
* checked the rest of the characters in the chunk signature) */
if (chunk[3] == 0x4C) {
is_pmgl = 1;
entries_off = pmgl_Entries;
}
else {
is_pmgl = 0;
entries_off = pmgi_Entries;
}
/* Step 1: binary search first filename of each QR entry
* - target filename == entry
* found file
* - target filename < all entries
* file not found
* - target filename > all entries
* proceed to step 2 using final entry
* - target filename between two searched entries
* proceed to step 2
*/
qr_size = EndGetI32(&chunk[pmgl_QuickRefSize]);
start = &chunk[chm->chunk_size - 2];
end = &chunk[chm->chunk_size - qr_size];
num_entries = EndGetI16(start);
qr_density = 1 + (1 << chm->density);
qr_entries = (num_entries + qr_density-1) / qr_density;
if (num_entries == 0) {
D(("chunk has no entries"))
return -1;
}
if (qr_size > chm->chunk_size) {
D(("quickref size > chunk size"))
return -1;
}
*result_end = end;
if (((int)qr_entries * 2) > (start - end)) {
D(("WARNING; more quickrefs than quickref space"))
qr_entries = 0; /* but we can live with it */
}
if (qr_entries > 0) {
L = 0;
R = qr_entries - 1;
do {
/* pick new midpoint */
M = (L + R) >> 1;
/* compare filename with entry QR points to */
p = &chunk[entries_off + (M ? EndGetI16(start - (M << 1)) : 0)];
READ_ENCINT(name_len);
if (name_len > (unsigned int) (end - p)) goto chunk_end;
cmp = compare(filename, (char *)p, fname_len, name_len);
if (cmp == 0) break;
else if (cmp < 0) { if (M) R = M - 1; else return 0; }
else if (cmp > 0) L = M + 1;
} while (L <= R);
M = (L + R) >> 1;
if (cmp == 0) {
/* exact match! */
p += name_len;
*result = p;
return 1;
}
/* otherwise, read the group of entries for QR entry M */
p = &chunk[entries_off + (M ? EndGetI16(start - (M << 1)) : 0)];
num_entries -= (M * qr_density);
if (num_entries > qr_density) num_entries = qr_density;
}
else {
p = &chunk[entries_off];
}
/* Step 2: linear search through the set of entries reached in step 1.
* - filename == any entry
* found entry
* - filename < all entries (PMGI) or any entry (PMGL)
* entry not found, stop now
* - filename > all entries
* entry not found (PMGL) / maybe found (PMGI)
* -
*/
*result = NULL;
while (num_entries-- > 0) {
READ_ENCINT(name_len);
if (name_len > (unsigned int) (end - p)) goto chunk_end;
cmp = compare(filename, (char *)p, fname_len, name_len);
p += name_len;
if (cmp == 0) {
/* entry found */
*result = p;
return 1;
}
if (cmp < 0) {
/* entry not found (PMGL) / maybe found (PMGI) */
break;
}
/* read and ignore the rest of this entry */
if (is_pmgl) {
READ_ENCINT(R); /* skip section */
READ_ENCINT(R); /* skip offset */
READ_ENCINT(R); /* skip length */
}
else {
*result = p; /* store potential final result */
READ_ENCINT(R); /* skip chunk number */
}
}
/* PMGL? not found. PMGI? maybe found */
return (is_pmgl) ? 0 : (*result ? 1 : 0);
chunk_end:
D(("reached end of chunk data while searching"))
return -1;
}
#if HAVE_TOWLOWER
# include <wctype.h>
# define TOLOWER(x) towlower(x)
#else
# include <ctype.h>
# define TOLOWER(x) tolower(x)
#endif
/* decodes a UTF-8 character from s[] into c. Will not read past e.
* doesn't test that extension bytes are %10xxxxxx.
* allows some overlong encodings.
*/
#define GET_UTF8_CHAR(s, e, c) do { \
unsigned char x = *s++; \
if (x < 0x80) c = x; \
else if (x >= 0xC2 && x < 0xE0 && s < e) { \
c = (x & 0x1F) << 6 | (*s++ & 0x3F); \
} \
else if (x >= 0xE0 && x < 0xF0 && s+1 < e) { \
c = (x & 0x0F) << 12 | (s[0] & 0x3F) << 6 | (s[1] & 0x3F); \
s += 2; \
} \
else if (x >= 0xF0 && x <= 0xF5 && s+2 < e) { \
c = (x & 0x07) << 18 | (s[0] & 0x3F) << 12 | \
(s[1] & 0x3F) << 6 | (s[2] & 0x3F); \
if (c > 0x10FFFF) c = 0xFFFD; \
s += 3; \
} \
else c = 0xFFFD; \
} while (0)
/* case-insensitively compares two UTF8 encoded strings. String length for
* both strings must be provided, null bytes are not terminators */
static inline int compare(const char *s1, const char *s2, int l1, int l2) {
register const unsigned char *p1 = (const unsigned char *) s1;
register const unsigned char *p2 = (const unsigned char *) s2;
register const unsigned char *e1 = p1 + l1, *e2 = p2 + l2;
int c1, c2;
while (p1 < e1 && p2 < e2) {
GET_UTF8_CHAR(p1, e1, c1);
GET_UTF8_CHAR(p2, e2, c2);
if (c1 == c2) continue;
c1 = TOLOWER(c1);
c2 = TOLOWER(c2);
if (c1 != c2) return c1 - c2;
}
return l1 - l2;
}
/***************************************
* CHMD_EXTRACT
***************************************
* extracts a file from a CHM helpfile
*/
static int chmd_extract(struct mschm_decompressor *base,
struct mschmd_file *file, const char *filename)
{
struct mschm_decompressor_p *self = (struct mschm_decompressor_p *) base;
struct mspack_system *sys;
struct mschmd_header *chm;
struct mspack_file *fh;
off_t bytes;
if (!self) return MSPACK_ERR_ARGS;
if (!file || !file->section) return self->error = MSPACK_ERR_ARGS;
sys = self->system;
chm = file->section->chm;
/* create decompression state if it doesn't exist */
if (!self->d) {
self->d = (struct mschmd_decompress_state *) sys->alloc(sys, sizeof(struct mschmd_decompress_state));
if (!self->d) return self->error = MSPACK_ERR_NOMEMORY;
self->d->chm = chm;
self->d->offset = 0;
self->d->state = NULL;
self->d->sys = *sys;
self->d->sys.write = &chmd_sys_write;
self->d->infh = NULL;
self->d->outfh = NULL;
}
/* open input chm file if not open, or the open one is a different chm */
if (!self->d->infh || (self->d->chm != chm)) {
if (self->d->infh) sys->close(self->d->infh);
if (self->d->state) lzxd_free(self->d->state);
self->d->chm = chm;
self->d->offset = 0;
self->d->state = NULL;
self->d->infh = sys->open(sys, chm->filename, MSPACK_SYS_OPEN_READ);
if (!self->d->infh) return self->error = MSPACK_ERR_OPEN;
}
/* open file for output */
if (!(fh = sys->open(sys, filename, MSPACK_SYS_OPEN_WRITE))) {
return self->error = MSPACK_ERR_OPEN;
}
/* if file is empty, simply creating it is enough */
if (!file->length) {
sys->close(fh);
return self->error = MSPACK_ERR_OK;
}
self->error = MSPACK_ERR_OK;
switch (file->section->id) {
case 0: /* Uncompressed section file */
/* simple seek + copy */
if (sys->seek(self->d->infh, file->section->chm->sec0.offset
+ file->offset, MSPACK_SYS_SEEK_START))
{
self->error = MSPACK_ERR_SEEK;
}
else {
unsigned char buf[512];
off_t length = file->length;
while (length > 0) {
int run = sizeof(buf);
if ((off_t)run > length) run = (int)length;
if (sys->read(self->d->infh, &buf[0], run) != run) {
self->error = MSPACK_ERR_READ;
break;
}
if (sys->write(fh, &buf[0], run) != run) {
self->error = MSPACK_ERR_WRITE;
break;
}
length -= run;
}
}
break;
case 1: /* MSCompressed section file */
/* (re)initialise compression state if we it is not yet initialised,
* or we have advanced too far and have to backtrack
*/
if (!self->d->state || (file->offset < self->d->offset)) {
if (self->d->state) {
lzxd_free(self->d->state);
self->d->state = NULL;
}
if (chmd_init_decomp(self, file)) break;
}
/* seek to input data */
if (sys->seek(self->d->infh, self->d->inoffset, MSPACK_SYS_SEEK_START)) {
self->error = MSPACK_ERR_SEEK;
break;
}
/* get to correct offset. */
self->d->outfh = NULL;
if ((bytes = file->offset - self->d->offset)) {
self->error = lzxd_decompress(self->d->state, bytes);
}
/* if getting to the correct offset was error free, unpack file */
if (!self->error) {
self->d->outfh = fh;
self->error = lzxd_decompress(self->d->state, file->length);
}
/* save offset in input source stream, in case there is a section 0
* file between now and the next section 1 file extracted */
self->d->inoffset = sys->tell(self->d->infh);
/* if an LZX error occured, the LZX decompressor is now useless */
if (self->error) {
if (self->d->state) lzxd_free(self->d->state);
self->d->state = NULL;
}
break;
}
sys->close(fh);
return self->error;
}
/***************************************
* CHMD_SYS_WRITE
***************************************
* chmd_sys_write is the internal writer function which the decompressor
* uses. If either writes data to disk (self->d->outfh) with the real
* sys->write() function, or does nothing with the data when
* self->d->outfh == NULL. advances self->d->offset.
*/
static int chmd_sys_write(struct mspack_file *file, void *buffer, int bytes) {
struct mschm_decompressor_p *self = (struct mschm_decompressor_p *) file;
self->d->offset += bytes;
if (self->d->outfh) {
return self->system->write(self->d->outfh, buffer, bytes);
}
return bytes;
}
/***************************************
* CHMD_INIT_DECOMP
***************************************
* Initialises the LZX decompressor to decompress the compressed stream,
* from the nearest reset offset and length that is needed for the given
* file.
*/
static int chmd_init_decomp(struct mschm_decompressor_p *self,
struct mschmd_file *file)
{
int window_size, window_bits, reset_interval, entry, err;
struct mspack_system *sys = self->system;
struct mschmd_sec_mscompressed *sec;
unsigned char *data;
off_t length, offset;
sec = (struct mschmd_sec_mscompressed *) file->section;
/* ensure we have a mscompressed content section */
err = find_sys_file(self, sec, &sec->content, content_name);
if (err) return self->error = err;
/* ensure we have a ControlData file */
err = find_sys_file(self, sec, &sec->control, control_name);
if (err) return self->error = err;
/* read ControlData */
if (sec->control->length < lzxcd_SIZEOF) {
D(("ControlData file is too short"))
return self->error = MSPACK_ERR_DATAFORMAT;
}
if (!(data = read_sys_file(self, sec->control))) {
D(("can't read mscompressed control data file"))
return self->error;
}
/* check LZXC signature */
if (EndGetI32(&data[lzxcd_Signature]) != 0x43585A4C) {
sys->free(data);
return self->error = MSPACK_ERR_SIGNATURE;
}
/* read reset_interval and window_size and validate version number */
switch (EndGetI32(&data[lzxcd_Version])) {
case 1:
reset_interval = EndGetI32(&data[lzxcd_ResetInterval]);
window_size = EndGetI32(&data[lzxcd_WindowSize]);
break;
case 2:
reset_interval = EndGetI32(&data[lzxcd_ResetInterval]) * LZX_FRAME_SIZE;
window_size = EndGetI32(&data[lzxcd_WindowSize]) * LZX_FRAME_SIZE;
break;
default:
D(("bad controldata version"))
sys->free(data);
return self->error = MSPACK_ERR_DATAFORMAT;
}
/* free ControlData */
sys->free(data);
/* find window_bits from window_size */
switch (window_size) {
case 0x008000: window_bits = 15; break;
case 0x010000: window_bits = 16; break;
case 0x020000: window_bits = 17; break;
case 0x040000: window_bits = 18; break;
case 0x080000: window_bits = 19; break;
case 0x100000: window_bits = 20; break;
case 0x200000: window_bits = 21; break;
default:
D(("bad controldata window size"))
return self->error = MSPACK_ERR_DATAFORMAT;
}
/* validate reset_interval */
if (reset_interval == 0 || reset_interval % LZX_FRAME_SIZE) {
D(("bad controldata reset interval"))
return self->error = MSPACK_ERR_DATAFORMAT;
}
/* which reset table entry would we like? */
entry = file->offset / reset_interval;
/* convert from reset interval multiple (usually 64k) to 32k frames */
entry *= reset_interval / LZX_FRAME_SIZE;
/* read the reset table entry */
if (read_reset_table(self, sec, entry, &length, &offset)) {
/* the uncompressed length given in the reset table is dishonest.
* the uncompressed data is always padded out from the given
* uncompressed length up to the next reset interval */
length += reset_interval - 1;
length &= -reset_interval;
}
else {
/* if we can't read the reset table entry, just start from
* the beginning. Use spaninfo to get the uncompressed length */
entry = 0;
offset = 0;
err = read_spaninfo(self, sec, &length);
}
if (err) return self->error = err;
/* get offset of compressed data stream:
* = offset of uncompressed section from start of file
* + offset of compressed stream from start of uncompressed section
* + offset of chosen reset interval from start of compressed stream */
self->d->inoffset = file->section->chm->sec0.offset + sec->content->offset + offset;
/* set start offset and overall remaining stream length */
self->d->offset = entry * LZX_FRAME_SIZE;
length -= self->d->offset;
/* initialise LZX stream */
self->d->state = lzxd_init(&self->d->sys, self->d->infh,
(struct mspack_file *) self, window_bits,
reset_interval / LZX_FRAME_SIZE,
4096, length, 0);
if (!self->d->state) self->error = MSPACK_ERR_NOMEMORY;
return self->error;
}
/***************************************
* READ_RESET_TABLE
***************************************
* Reads one entry out of the reset table. Also reads the uncompressed
* data length. Writes these to offset_ptr and length_ptr respectively.
* Returns non-zero for success, zero for failure.
*/
static int read_reset_table(struct mschm_decompressor_p *self,
struct mschmd_sec_mscompressed *sec,
unsigned int entry,
off_t *length_ptr, off_t *offset_ptr)
{
struct mspack_system *sys = self->system;
unsigned char *data;
unsigned int pos, entrysize;
/* do we have a ResetTable file? */
int err = find_sys_file(self, sec, &sec->rtable, rtable_name);
if (err) return 0;
/* read ResetTable file */
if (sec->rtable->length < lzxrt_headerSIZEOF) {
D(("ResetTable file is too short"))
return 0;
}
if (!(data = read_sys_file(self, sec->rtable))) {
D(("can't read reset table"))
return 0;
}
/* check sanity of reset table */
if (EndGetI32(&data[lzxrt_FrameLen]) != LZX_FRAME_SIZE) {
D(("bad reset table frame length"))
sys->free(data);
return 0;
}
/* get the uncompressed length of the LZX stream */
if (read_off64(length_ptr, &data[lzxrt_UncompLen], sys, self->d->infh)) {
sys->free(data);
return 0;
}
entrysize = EndGetI32(&data[lzxrt_EntrySize]);
pos = EndGetI32(&data[lzxrt_TableOffset]) + (entry * entrysize);
/* ensure reset table entry for this offset exists */
if (entry < EndGetI32(&data[lzxrt_NumEntries]) &&
pos <= (sec->rtable->length - entrysize))
{
switch (entrysize) {
case 4:
*offset_ptr = EndGetI32(&data[pos]);
err = 0;
break;
case 8:
err = read_off64(offset_ptr, &data[pos], sys, self->d->infh);
break;
default:
D(("reset table entry size neither 4 nor 8"))
err = 1;
break;
}
}
else {
D(("bad reset interval"))
err = 1;
}
/* free the reset table */
sys->free(data);
/* return success */
return (err == 0);
}
/***************************************
* READ_SPANINFO
***************************************
* Reads the uncompressed data length from the spaninfo file.
* Returns zero for success or a non-zero error code for failure.
*/
static int read_spaninfo(struct mschm_decompressor_p *self,
struct mschmd_sec_mscompressed *sec,
off_t *length_ptr)
{
struct mspack_system *sys = self->system;
unsigned char *data;
/* find SpanInfo file */
int err = find_sys_file(self, sec, &sec->spaninfo, spaninfo_name);
if (err) return MSPACK_ERR_DATAFORMAT;
/* check it's large enough */
if (sec->spaninfo->length != 8) {
D(("SpanInfo file is wrong size"))
return MSPACK_ERR_DATAFORMAT;
}
/* read the SpanInfo file */
if (!(data = read_sys_file(self, sec->spaninfo))) {
D(("can't read SpanInfo file"))
return self->error;
}
/* get the uncompressed length of the LZX stream */
err = read_off64(length_ptr, data, sys, self->d->infh);
sys->free(data);
if (err) return MSPACK_ERR_DATAFORMAT;
if (*length_ptr <= 0) {
D(("output length is invalid"))
return MSPACK_ERR_DATAFORMAT;
}
return MSPACK_ERR_OK;
}
/***************************************
* FIND_SYS_FILE
***************************************
* Uses chmd_fast_find to locate a system file, and fills out that system
* file's entry and links it into the list of system files. Returns zero
* for success, non-zero for both failure and the file not existing.
*/
static int find_sys_file(struct mschm_decompressor_p *self,
struct mschmd_sec_mscompressed *sec,
struct mschmd_file **f_ptr, const char *name)
{
struct mspack_system *sys = self->system;
struct mschmd_file result;
/* already loaded */
if (*f_ptr) return MSPACK_ERR_OK;
/* try using fast_find to find the file - return DATAFORMAT error if
* it fails, or successfully doesn't find the file */
if (chmd_fast_find((struct mschm_decompressor *) self, sec->base.chm,
name, &result, (int)sizeof(result)) || !result.section)
{
return MSPACK_ERR_DATAFORMAT;
}
if (!(*f_ptr = (struct mschmd_file *) sys->alloc(sys, sizeof(result)))) {
return MSPACK_ERR_NOMEMORY;
}
/* copy result */
*(*f_ptr) = result;
(*f_ptr)->filename = (char *) name;
/* link file into sysfiles list */
(*f_ptr)->next = sec->base.chm->sysfiles;
sec->base.chm->sysfiles = *f_ptr;
return MSPACK_ERR_OK;
}
/***************************************
* READ_SYS_FILE
***************************************
* Allocates memory for a section 0 (uncompressed) file and reads it into
* memory.
*/
static unsigned char *read_sys_file(struct mschm_decompressor_p *self,
struct mschmd_file *file)
{
struct mspack_system *sys = self->system;
unsigned char *data = NULL;
int len;
if (!file || !file->section || (file->section->id != 0)) {
self->error = MSPACK_ERR_DATAFORMAT;
return NULL;
}
len = (int) file->length;
if (!(data = (unsigned char *) sys->alloc(sys, (size_t) len))) {
self->error = MSPACK_ERR_NOMEMORY;
return NULL;
}
if (sys->seek(self->d->infh, file->section->chm->sec0.offset
+ file->offset, MSPACK_SYS_SEEK_START))
{
self->error = MSPACK_ERR_SEEK;
sys->free(data);
return NULL;
}
if (sys->read(self->d->infh, data, len) != len) {
self->error = MSPACK_ERR_READ;
sys->free(data);
return NULL;
}
return data;
}
/***************************************
* CHMD_ERROR
***************************************
* returns the last error that occurred
*/
static int chmd_error(struct mschm_decompressor *base) {
struct mschm_decompressor_p *self = (struct mschm_decompressor_p *) base;
return (self) ? self->error : MSPACK_ERR_ARGS;
}
/***************************************
* READ_OFF64
***************************************
* Reads a 64-bit signed integer from memory in Intel byte order.
* If running on a system with a 64-bit off_t, this is simply done.
* If running on a system with a 32-bit off_t, offsets up to 0x7FFFFFFF
* are accepted, offsets beyond that cause an error message.
*/
static int read_off64(off_t *var, unsigned char *mem,
struct mspack_system *sys, struct mspack_file *fh)
{
#if LARGEFILE_SUPPORT
*var = EndGetI64(mem);
#else
*var = EndGetI32(mem);
if ((*var & 0x80000000) || EndGetI32(mem+4)) {
sys->message(fh, (char *)largefile_msg);
return 1;
}
#endif
return 0;
}