无论出于何种原因，MinGW的gcc似乎无法找到此变量的'#define'块。完整错误是
.../mapped.c:396:28: error: '_zzip_strcasecmp' undeclared (first use in this function)
mapped.c的内容：
/*
* NOTE: this is part of libzzipmmapped (i.e. it is not libzzip).
* ==================
*
* These routines are fully independent from the traditional zzip
* implementation. They assume a readonly mmapped sharedmem block
* representing a complete zip file. The functions show how to
* parse the structure, find files and return a decoded bytestream.
*
* These routines are a bit simple and really here for documenting
* the way to access a zip file. The complexity of zip access comes
* from staggered reading of bytes and reposition of a filepointer in
* a big archive with lots of files and long compressed datastreams.
* Plus varaints of drop-in stdio replacements, obfuscation routines,
* auto fileextensions, drop-in dirent replacements, and so on...
*
* Author:
* Guido Draheim <guidod@gmx.de>
*
* Copyright (c) 2003,2004,2006 Guido Draheim
* All rights reserved,
* use under the restrictions of the
* Lesser GNU General Public License
* or alternatively the restrictions
* of the Mozilla Public License 1.1
*/
#define _ZZIP_DISK_FILE_STRUCT 1
#ifdef __linux__
#define _GNU_SOURCE _glibc_developers_are_idiots_to_call_strndup_gnu_specific_
#endif
#include <zzip/mmapped.h>
#include <zzip/format.h>
#include <zzip/fetch.h>
#include <zzip/__mmap.h>
#include <zzip/__fnmatch.h>
#include <stdlib.h>
#include <sys/stat.h>
#if defined ZZIP_HAVE_UNISTD_H
#include <unistd.h>
#elif defined ZZIP_HAVE_IO_H
#include <io.h>
#endif
#if defined ZZIP_HAVE_STRING_H
#include <string.h>
#elif defined ZZIP_HAVE_STRINGS_H
#include <strings.h>
#endif
#if __STDC_VERSION__+0 > 199900L
#define ___
#define ____
#else
#define ___ {
#define ____ }
#endif
/** => zzip_disk_mmap
* This function does primary initialization of a disk-buffer struct.
*/
int
zzip_disk_init(ZZIP_DISK* disk, void* buffer, zzip_size_t buflen)
{
disk->buffer = (zzip_byte_t*) buffer;
disk->endbuf = (zzip_byte_t*) buffer + buflen;
disk->reserved = 0;
disk->flags = 0;
disk->mapped = 0;
/* do not touch disk->user */
/* do not touch disk->code */
return 0;
}
/** => zzip_disk_mmap
* This function allocates a new disk-buffer with => malloc(3)
*/
zzip__new__ ZZIP_DISK*
zzip_disk_new(void)
{
ZZIP_DISK* disk = malloc(sizeof(disk));
if (! disk) return disk;
zzip_disk_init (disk, 0, 0);
return disk;
}
/** turn a filehandle into a mmapped zip disk archive handle
*
* This function uses the given file-descriptor to detect the length of the
* file and calls the system => mmap(2) to put it in main memory. If it is
* successful then a newly allocated ZZIP_DISK* is returned with
* disk->buffer pointing to the mapview of the zipdisk content.
*/
zzip__new__ ZZIP_DISK*
zzip_disk_mmap(int fd)
{
struct stat st;
if (fstat (fd, &st) || ! st.st_size) return 0;
___ ZZIP_DISK* disk = zzip_disk_new (); if (! disk) return 0;
disk->buffer = _zzip_mmap (& disk->mapped, fd, 0, st.st_size);
if (disk->buffer == MAP_FAILED) { free (disk); return 0; }
disk->endbuf = disk->buffer + st.st_size;
return disk; ____;
}
/** => zzip_disk_mmap
* This function is the inverse of => zzip_disk_mmap and using the system
* munmap(2) on the buffer area and => free(3) on the ZZIP_DISK structure.
*/
int
zzip_disk_munmap(ZZIP_DISK* disk)
{
if (! disk) return 0;
_zzip_munmap (disk->mapped, disk->buffer, disk->endbuf-disk->buffer);
free (disk);
return 0;
}
/** => zzip_disk_mmap
*
* This function opens the given archive by name and turn the filehandle
* to => zzip_disk_mmap for bringing it to main memory. If it can not
* be => mmap(2)'ed then we slurp the whole file into a newly => malloc(2)'ed
* memory block. Only if that fails too then we return null. Since handling
* of disk->buffer is ambigous it should not be snatched away please.
*/
ZZIP_DISK* zzip__new__
zzip_disk_open(char* filename)
{
# ifndef O_BINARY
# define O_BINARY 0
# endif
struct stat st;
if (stat (filename, &st) || ! st.st_size) return 0;
___ int fd = open (filename, O_RDONLY|O_BINARY);
if (fd <= 0) return 0;
___ ZZIP_DISK* disk = zzip_disk_mmap (fd);
if (disk) return disk;
___ zzip_byte_t* buffer = malloc (st.st_size);
if (! buffer) return 0;
if ((st.st_size == read (fd, buffer, st.st_size)) &&
(disk = zzip_disk_new ()))
{
disk->buffer = buffer;
disk->endbuf = buffer+st.st_size;
disk->mapped = -1;
}else free (buffer);
return disk; ____;____;____;
}
/** => zzip_disk_mmap
*
* This function will release all data needed to access a (mmapped)
* zip archive, including any malloc()ed blocks, sharedmem mappings
* and it dumps the handle struct as well.
*/
int
zzip_disk_close(ZZIP_DISK* disk)
{
if (! disk) return 0;
if (disk->mapped != -1) return zzip_disk_munmap (disk);
free (disk->buffer);
free (disk);
return 0;
}
/* ====================================================================== */
/* helper functions */
#ifdef ZZIP_HAVE_STRNDUP
#define _zzip_strndup strndup
#else
/* if your system does not have strndup: */
zzip__new__ static char* _zzip_strndup(char* p, size_t maxlen)
{
if (! p) return 0;
___ zzip_byte_t* r = malloc (maxlen+1);
if (! r) return r;
strncpy (r, p, maxlen);
r[maxlen] = '\0';
return r; ____;
}
#endif
#if defined ZZIP_HAVE_STRCASECMP || defined strcasecmp
#define _zzip_strcasecmp strcasecmp
#else
/* if your system does not have strcasecmp: */
static int _zzip_strcasecmp(char* __zzip_restrict a, char* _zzip_restrict b)
{
if (! a) return (b) ? 1 : 0;
if (! b) return -1;
while (1)
{
int v = tolower(*a) - tolower(*b);
if (v) return v;
if (! *a) return 1;
if (! *b) return -1;
a++; b++;
}
}
#endif
/** helper functions for (mmapped) zip access api
*
* This function augments the other zzip_disk_entry_* helpers: here we move
* a disk_entry pointer (as returned by _find* functions) into a pointer to
* the data block right after the file_header. Only disk->buffer would be
* needed to perform the seek but we check the mmapped range end as well.
*/
zzip_byte_t*
zzip_disk_entry_to_data(ZZIP_DISK* disk, struct zzip_disk_entry* entry)
{
struct zzip_file_header* file =
zzip_disk_entry_to_file_header(disk, entry);
if (file) return zzip_file_header_to_data (file);
return 0;
}
/** => zzip_disk_entry_to_data
* This function does half the job of => zzip_disk_entry_to_data where it
* can augment with => zzip_file_header_to_data helper from format/fetch.h
*/
struct zzip_file_header*
zzip_disk_entry_to_file_header(ZZIP_DISK* disk, struct zzip_disk_entry* entry)
{
zzip_byte_t* file_header = /* (struct zzip_file_header*) */
(disk->buffer + zzip_disk_entry_fileoffset (entry));
if (disk->buffer > file_header || file_header >= disk->endbuf)
return 0;
return (struct zzip_file_header*) file_header;
}
/** => zzip_disk_entry_to_data
* This function is a big helper despite its little name: in a zip file the
* encoded filenames are usually NOT zero-terminated but for common usage
* with libc we need it that way. Secondly, the filename SHOULD be present
* in the zip central directory but if not then we fallback to the filename
* given in the file_header of each compressed data portion.
*/
zzip__new__ char*
zzip_disk_entry_strdup_name(ZZIP_DISK* disk, struct zzip_disk_entry* entry)
{
if (! disk || ! entry) return 0;
___ char* name; zzip_size_t len;
struct zzip_file_header* file;
if ((len = zzip_disk_entry_namlen (entry)))
name = zzip_disk_entry_to_filename (entry);
else if ((file = zzip_disk_entry_to_file_header (disk, entry)) &&
(len = zzip_file_header_namlen (file)))
name = zzip_file_header_to_filename (file);
else
return 0;
if ((zzip_byte_t*) name < disk->buffer ||
(zzip_byte_t*) name+len > disk->endbuf)
return 0;
return _zzip_strndup (name, len); ____;
}
/** => zzip_disk_entry_to_data
* This function is similar creating a reference to a zero terminated
* string but it can only exist in the zip central directory entry.
*/
zzip__new__ char*
zzip_disk_entry_strdup_comment(ZZIP_DISK* disk, struct zzip_disk_entry* entry)
{
if (! disk || ! entry) return 0;
___ char* text; zzip_size_t len;
if ((len = zzip_disk_entry_comment (entry)))
text = zzip_disk_entry_to_comment (entry);
else
return 0;
if ((zzip_byte_t*) text < disk->buffer ||
(zzip_byte_t*) text+len > disk->endbuf)
return 0;
return _zzip_strndup (text, len); ____;
}
/* ====================================================================== */
/** => zzip_disk_findfile
*
* This function is the first call of all the zip access functions here.
* It contains the code to find the first entry of the zip central directory.
* Here we require the mmapped block to represent a real zip file where the
* disk_trailer is _last_ in the file area, so that its position would be at
* a fixed offset from the end of the file area if not for the comment field
* allowed to be of variable length (which needs us to do a little search
* for the disk_tailer). However, in this simple implementation we disregard
* any disk_trailer info telling about multidisk archives, so we just return
* a pointer to the zip central directory.
*
* For an actual means, we are going to search backwards from the end
* of the mmaped block looking for the PK-magic signature of a
* disk_trailer. If we see one then we check the rootseek value to
* find the first disk_entry of the root central directory. If we find
* the correct PK-magic signature of a disk_entry over there then we
* assume we are done and we are going to return a pointer to that label.
*
* The return value is a pointer to the first zzip_disk_entry being checked
* to be within the bounds of the file area specified by the arguments. If
* no disk_trailer was found then null is returned, and likewise we only
* accept a disk_trailer with a seekvalue that points to a disk_entry and
* both parts have valid PK-magic parts. Beyond some sanity check we try to
* catch a common brokeness with zip archives that still allows us to find
* the start of the zip central directory.
*/
struct zzip_disk_entry*
zzip_disk_findfirst(ZZIP_DISK* disk)
{
if (disk->buffer > disk->endbuf-sizeof(struct zzip_disk_trailer))
return 0;
___ zzip_byte_t* p = disk->endbuf-sizeof(struct zzip_disk_trailer);
for (; p >= disk->buffer ; p--)
{
zzip_byte_t* root; /* (struct zzip_disk_entry*) */
if (zzip_disk_trailer_check_magic(p)) {
root = disk->buffer + zzip_disk_trailer_get_rootseek (
(struct zzip_disk_trailer*)p);
if (root > p)
{ /* the first disk_entry is after the disk_trailer? can't be! */
zzip_size_t rootsize = zzip_disk_trailer_get_rootsize (
(struct zzip_disk_trailer*)p);
if (disk->buffer+rootsize > p) continue;
/* a common brokeness that can be fixed: we just assume the
* central directory was written directly before the trailer:*/
root = p - rootsize;
}
} else if (zzip_disk64_trailer_check_magic(p)) {
if (sizeof(void*) < 8) return 0; /* EOVERFLOW */
root = disk->buffer + zzip_disk64_trailer_get_rootseek (
(struct zzip_disk64_trailer*)p);
if (root > p) continue;
} else continue;
if (root < disk->buffer) continue;
if (zzip_disk_entry_check_magic(root))
return (struct zzip_disk_entry*) root;
}____;
return 0;
}
/** => zzip_disk_findfile
*
* This function takes an existing disk_entry in the central root directory
* (e.g. from zzip_disk_findfirst) and returns the next entry within in
* the given bounds of the mmapped file area.
*/
struct zzip_disk_entry*
zzip_disk_findnext(ZZIP_DISK* disk, struct zzip_disk_entry* entry)
{
if ((zzip_byte_t*)entry < disk->buffer ||
(zzip_byte_t*)entry > disk->endbuf-sizeof(entry) ||
! zzip_disk_entry_check_magic (entry) ||
zzip_disk_entry_sizeto_end (entry) > 64*1024)
return 0;
entry = zzip_disk_entry_to_next_entry (entry);
if ((zzip_byte_t*)entry > disk->endbuf-sizeof(entry) ||
! zzip_disk_entry_check_magic (entry) ||
zzip_disk_entry_sizeto_end (entry) > 64*1024 ||
zzip_disk_entry_skipto_end (entry) + sizeof(entry) > disk->endbuf)
return 0;
else
return entry;
}
/** search for files in the (mmapped) zip central directory
*
* This function is given a filename as an additional argument, to find the
* disk_entry matching a given filename. The compare-function is usually
* strcmp or strcasecmp or perhaps strcoll, if null then strcmp is used.
* - use null as argument for "after"-entry when searching the first
* matching entry, otherwise the last returned value if you look for other
* entries with a special "compare" function (if null then a doubled search
* is rather useless with this variant of _findfile).
*/
struct zzip_disk_entry*
zzip_disk_findfile(ZZIP_DISK* disk, char* filename,
struct zzip_disk_entry* after, zzip_strcmp_fn_t compare)
{
struct zzip_disk_entry* entry = (! after ? zzip_disk_findfirst (disk)
: zzip_disk_findnext (disk, after));
if (! compare)
compare = (zzip_strcmp_fn_t)( (disk->flags&1) ?
(_zzip_strcasecmp) : (strcmp));
for (; entry ; entry = zzip_disk_findnext (disk, entry))
{
/* filenames within zip files are often not null-terminated! */
char* realname = zzip_disk_entry_strdup_name (disk, entry);
if (realname && ! compare(filename, realname))
{
free (realname);
return entry;
}
free (realname);
}
return 0;
}
/** => zzip_disk_findfile
*
* This function uses a compare-function with an additional argument
* and it is called just like fnmatch(3) from POSIX.2 AD:1993), i.e.
* the argument filespec first and the ziplocal filename second with
* the integer-flags put in as third to the indirect call. If the
* platform has fnmatch available then null-compare will use that one
* and otherwise we fall back to mere strcmp, so if you need fnmatch
* searching then please provide an implementation somewhere else.
* - use null as argument for "after"-entry when searching the first
* matching entry, or the last disk_entry return-value to find the
* next entry matching the given filespec.
*/
struct zzip_disk_entry*
zzip_disk_findmatch(ZZIP_DISK* disk, char* filespec,
struct zzip_disk_entry* after,
zzip_fnmatch_fn_t compare, int flags)
{
struct zzip_disk_entry* entry = (! after ? zzip_disk_findfirst (disk)
: zzip_disk_findnext (disk, after));
if (! compare) {
compare = (zzip_fnmatch_fn_t) _zzip_fnmatch;
if (disk->flags&1) disk->flags |= _zzip_fnmatch_CASEFOLD;
}
for (; entry ; entry = zzip_disk_findnext (disk, entry))
{
/* filenames within zip files are often not null-terminated! */
char* realname = zzip_disk_entry_strdup_name(disk, entry);
if (realname && ! compare(filespec, realname, flags))
{
free (realname);
return entry;
}
free (realname);
}
return 0;
}
/* ====================================================================== */
/** => zzip_disk_fopen
*
* the ZZIP_DISK_FILE* is rather simple in just encapsulating the
* arguments given to this function plus a zlib deflate buffer.
* Note that the ZZIP_DISK pointer does already contain the full
* mmapped file area of a zip disk, so open()ing a file part within
* that area happens to be a lookup of its bounds and encoding. That
* information is memorized on the ZZIP_DISK_FILE so that subsequent
* _read() operations will be able to get the next data portion or
* return an eof condition for that file part wrapped in the zip archive.
*/
zzip__new__ ZZIP_DISK_FILE*
zzip_disk_entry_fopen (ZZIP_DISK* disk, ZZIP_DISK_ENTRY* entry)
{
/* keep this in sync with zzip_mem_entry_fopen */
struct zzip_file_header* header =
zzip_disk_entry_to_file_header (disk, entry);
if (! header) return 0;
___ ZZIP_DISK_FILE* file = malloc(sizeof(ZZIP_DISK_FILE));
if (! file) return file;
file->buffer = disk->buffer;
file->endbuf = disk->endbuf;
file->avail = zzip_file_header_usize (header);
if (! file->avail || zzip_file_header_data_stored (header))
{ file->stored = zzip_file_header_to_data (header); return file; }
file->stored = 0;
file->zlib.opaque = 0;
file->zlib.zalloc = Z_NULL;
file->zlib.zfree = Z_NULL;
file->zlib.avail_in = zzip_file_header_csize (header);
file->zlib.next_in = zzip_file_header_to_data (header);
if (! zzip_file_header_data_deflated(header) ||
inflateInit2(&file->zlib, -MAX_WBITS) != Z_OK)
{ free (file); return 0; }
return file;
____;
}
/** openening a file part wrapped within a (mmapped) zip archive
*
* This function opens a file found by name, so it does a search into
* the zip central directory with => zzip_disk_findfile and whatever
* is found first is given to => zzip_disk_entry_fopen
*/
zzip__new__ ZZIP_DISK_FILE*
zzip_disk_fopen (ZZIP_DISK* disk, char* filename)
{
ZZIP_DISK_ENTRY* entry = zzip_disk_findfile (disk, filename, 0, 0);
if (! entry) return 0; else return zzip_disk_entry_fopen (disk, entry);
}
/** => zzip_disk_fopen
*
* This function reads more bytes into the output buffer specified as
* arguments. The return value is null on eof or error, the stdio-like
* interface can not distinguish between these so you need to check
* with => zzip_disk_feof for the difference.
*/
zzip_size_t
zzip_disk_fread (void* ptr, zzip_size_t sized, zzip_size_t nmemb,
ZZIP_DISK_FILE* file)
{
zzip_size_t size = sized*nmemb;
if (size > file->avail) size = file->avail;
if (file->stored)
{
memcpy (ptr, file->stored, size);
file->stored += size;
file->avail -= size;
return size;
}
file->zlib.avail_out = sized*nmemb;
file->zlib.next_out = ptr;
___ zzip_size_t total_old = file->zlib.total_out;
___ int err = inflate (& file->zlib, Z_NO_FLUSH);
if (err == Z_STREAM_END)
file->avail = 0;
else if (err == Z_OK)
file->avail -= file->zlib.total_out - total_old;
else
return 0;
return file->zlib.total_out - total_old;
____;____;
}
/** => zzip_disk_fopen
* This function releases any zlib decoder info needed for decompression
* and dumps the ZZIP_DISK_FILE* then.
*/
int
zzip_disk_fclose (ZZIP_DISK_FILE* file)
{
if (! file->stored)
inflateEnd (& file->zlib);
free (file);
return 0;
}
/** => zzip_disk_fopen
*
* This function allows to distinguish an error from an eof condition.
* Actually, if we found an error but we did already reach eof then we
* just keep on saying that it was an eof, so the app can just continue.
*/
int
zzip_disk_feof (ZZIP_DISK_FILE* file)
{
return ! file || ! file->avail;
}
有谁知道发生了什么事？对不起，如果你们中的一些人看起来很明显，我就是这个东西的新手。
谢谢！
编辑：由于我无法弄清楚什么是错的，我决定使用源代码附带的visual studio解决方案，最后我成功地构建了它。感谢所有试图帮助我的人。
答案 0 :(得分：4)
您的错误的原因是，()中包含的C语言名称不被视为宏。这实际上是专门为此目的而存在的语言的一个特性：让你有机会在你想要的时候“忽略”宏定义。
当您尝试使用GCC编译代码时，似乎strcasecmp可用。 #if的真正分支由编译器获取，这意味着_zzip_strcasecmp被定义为宏
#define _zzip_strcasecmp strcasecmp
只要您将其称为
，这将正常工作_zzip_strcasecmp( /* whatever */ )
但是当您将其称为(_zzip_strcasecmp)
compare = (zzip_strcmp_fn_t)( (disk->flags&1) ?
(_zzip_strcasecmp) : (strcmp));
编译器在查找(_zzip_strcasecmp)时将_zzip_strcasecmp视为忽略宏的请求。编译器将查找_zzip_strcasecmp的非宏定义，并失败并显示错误消息，因为此类定义不存在。
在Visual Siudio中编译时，strcasecmp不可用。取#if的假分支，_zzip_strcasecmp在内部定义为普通函数。所以，一切正常。
修复宏版本的一种方法是在有问题的错误陈述中删除这些过多的()函数名称
compare = (zzip_strcmp_fn_t)( (disk->flags&1) ?
_zzip_strcasecmp : strcmp);
这应该在GCC中编译，假设strcasecmp确实可用。
我不知道为什么他们将这些多余的()放在原始版本中。可能是“猖獗的括号”和错误的“更安全而不是抱歉”情绪的一个例子。实际上可能是故意做的，以防止在这种情况下使用宏（在这种情况下，坏人就是那个写#if的人。）