X-Git-Url: https://git.draconx.ca/gitweb/liblbx.git/blobdiff_plain/97ae1755d995159117c16a9410f696b936d3d4f0..6eccd43bbac449f6fd939278381d0e6219ba2e16:/src/lbx.c?ds=sidebyside diff --git a/src/lbx.c b/src/lbx.c index 3eac708..253da5e 100644 --- a/src/lbx.c +++ b/src/lbx.c @@ -1,8 +1,16 @@ +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + #include #include #include #include #include +#include + +#include +#include #include "byteorder.h" #include "lbx.h" @@ -15,6 +23,8 @@ int lbx_errno = 0; struct lbx_state { const char *name; + unsigned char *mem; + size_t memsize; FILE *f; long foff; @@ -70,6 +80,59 @@ readerr: return NULL; } +static int _lbx_memcpy(void *dest, struct lbx_state *src, size_t size) +{ + if (src->foff + size > src->memsize) + return -1; + memcpy(dest, src->mem + src->foff, size); + src->foff += size; + return 0; +} + +struct lbx_state *lbx_mopen(void *_mem, size_t size, const char *name) +{ + struct lbx_state *new = NULL; + struct lbx_state tmp = { .mem = _mem, .memsize = size }; + uint16_t nfiles, version; + uint32_t magic; + + if (_lbx_memcpy(&nfiles, &tmp, sizeof nfiles) == -1) goto eof; + if (_lbx_memcpy(&magic, &tmp, sizeof magic) == -1) goto eof; + if (_lbx_memcpy(&version, &tmp, sizeof version) == -1) goto eof; + + nfiles = letohs(nfiles); + magic = letohl(magic); + version = letohs(version); + + if (magic != LBX_MAGIC) { + lbx_errno = LBX_EMAGIC; + return NULL; + } + + new = malloc(sizeof *new + (nfiles+1)*(sizeof *new->offsets)); + if (!new) { + lbx_errno = -errno; + return NULL; + } + + *new = (struct lbx_state){ + .name = name, + .nfiles = nfiles, + .mem = _mem, + .memsize = size, + .foff = tmp.foff, + }; + + if (_lbx_memcpy(new->offsets, new, (nfiles+1)*(sizeof *new->offsets))) + goto eof; + + return new; +eof: + free(new); + lbx_errno = LBX_EEOF; + return NULL; +} + struct lbx_state *lbx_open(const char *path) { struct lbx_state *new = NULL; @@ -106,74 +169,78 @@ int lbx_stat(struct lbx_state *lbx, size_t index, struct lbx_statbuf *buf) return 0; } -/* - * Read and discard len bytes from the file. On success, returns 0. On - * failure, returns -1 and sets lbx_errno. - */ -static int skipdata(FILE *f, size_t len) +/* Advance to the beginning of the index'th file by either fseek or reading. */ +static int _lbx_fseek(struct lbx_state *lbx, size_t base) { - unsigned char buf[1024]; - - while (len) { - if (fread(buf, MIN(sizeof buf, len), 1, f) != 1) { - if (feof(f)) { - lbx_errno = LBX_EEOF; - } else { - lbx_errno = -errno; + static unsigned char oblivion[1024]; + long dist; + + if (lbx->foff < base) { + dist = base - lbx->foff; + } else if (lbx->foff > base) { + dist = -(long)(lbx->foff - base); + } else { + return 0; + } + + if (fseek(lbx->f, dist, SEEK_CUR) == 0) { + lbx->foff += dist; + } else if (lbx->foff < base) { + while (dist) { + size_t rc, amt = MIN(sizeof oblivion, dist); + rc = fread(oblivion, 1, amt, lbx->f); + lbx->foff += rc; + dist -= rc; + if (rc < amt) { + if (feof(lbx->f)) + lbx_errno = LBX_EEOF; + else + lbx_errno = -errno; + return -1; } - return -1; } - len -= MIN(sizeof buf, len); + } else { + lbx_errno = -errno; + return -1; } - return 0; } -size_t lbx_extract(struct lbx_state *lbx, size_t index, FILE *of) +static size_t +_lbx_mextract(struct lbx_state *lbx, size_t base, size_t len, FILE *of) +{ + size_t rc; + + assert(lbx->mem); + assert(base + len <= lbx->memsize); + + rc = fwrite(lbx->mem + base, 1, len, of); + if (rc < len) + lbx_errno = -errno; + + return rc; +} + +static size_t +_lbx_fextract(struct lbx_state *lbx, size_t base, size_t len, FILE *of) { unsigned char buf[1024]; - size_t rc, written = 0, base, len; + size_t rc, written = 0; - if (index >= lbx->nfiles) { - lbx_errno = LBX_ERANGE; + assert(lbx->f); + + if (_lbx_fseek(lbx, base) == -1) return 0; - } - base = lbx->offsets[index]; - len = lbx->offsets[index+1] - lbx->offsets[index]; - - /* Seek to the beginning of the file. */ - if (lbx->foff != base) { - int seekrc; - long dist = (lbx->foff < base) ? (base - lbx->foff) - : -(lbx->foff - base); - - seekrc = fseek(lbx->f, dist, SEEK_CUR); - if (seekrc == -1 && lbx->foff < base) { - if (skipdata(lbx->f, dist) == -1) { - /* lbx_errno set by skipdata */ - return 0; - } - } else if (seekrc == -1) { - lbx_errno = -errno; - return 0; - } - lbx->foff += dist; /* FIXME: failed skipdata breaks this. */ - } - - /* Copy file data */ while (len) { - size_t amt = MIN(sizeof buf, len); + size_t amt = MIN(len, sizeof buf); rc = fread(buf, 1, amt, lbx->f); lbx->foff += rc; len -= rc; if (rc < amt) { - if (feof(lbx->f)) { - lbx_errno = LBX_EEOF; - } else { - lbx_errno = -errno; - } + if (feof(lbx->f)) lbx_errno = LBX_EEOF; + else lbx_errno = -errno; break; } @@ -188,11 +255,67 @@ size_t lbx_extract(struct lbx_state *lbx, size_t index, FILE *of) return written; } +size_t lbx_extract(struct lbx_state *lbx, size_t index, FILE *of) +{ + size_t base, len; + + if (index >= lbx->nfiles) { + lbx_errno = LBX_ERANGE; + return 0; + } + + base = lbx->offsets[index]; + len = lbx->offsets[index+1] - lbx->offsets[index]; + + if (lbx->mem) + return _lbx_mextract(lbx, base, len, of); + return _lbx_fextract(lbx, base, len, of); +} + +void *lbx_mmap(struct lbx_state *lbx, size_t index, size_t *len) +{ + unsigned char *mapping; + struct stat statbuf; + size_t base; + + if (index >= lbx->nfiles) { + lbx_errno = LBX_ERANGE; + return NULL; + } + + base = lbx->offsets[index]; + *len = lbx->offsets[index+1] - lbx->offsets[index]; + + if (lbx->mem) + return lbx->mem + base; + + if (fstat(fileno(lbx->f), &statbuf) == -1) { + lbx_errno = -errno; + return NULL; + } + + mapping = mmap(NULL, statbuf.st_size, PROT_READ, 0, fileno(lbx->f), 0); + if (mapping == MAP_FAILED) { + lbx_errno = -errno; + return NULL; + } + + lbx->mem = mapping; + lbx->memsize = statbuf.st_size; + return mapping + base; +} + void lbx_close(struct lbx_state *lbx) { if (!lbx) return; - fclose(lbx->f); + if (lbx->f) { + fclose(lbx->f); + if (lbx->mem) { + munmap(lbx->mem, lbx->memsize); + } + } + free(lbx); }