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-rw-r--r--utils/rbutilqt/mspack/chmd.c1377
1 files changed, 1377 insertions, 0 deletions
diff --git a/utils/rbutilqt/mspack/chmd.c b/utils/rbutilqt/mspack/chmd.c
new file mode 100644
index 0000000000..6c8481db14
--- /dev/null
+++ b/utils/rbutilqt/mspack/chmd.c
@@ -0,0 +1,1377 @@
+/* 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-mspack.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;
+}