#include <string.h>
#include <stdint.h>
#include <errno.h>
+#include <assert.h>
+
+#include <sys/stat.h>
+#include <sys/mman.h>
#include "byteorder.h"
#include "lbx.h"
#define LBX_MAGIC 0x0000fead
+#define MIN(a,b) (((a)<(b))?(a):(b))
int lbx_errno = 0;
struct lbx_state {
const char *name;
+ unsigned char *mem;
+ size_t memsize;
FILE *f;
long foff;
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;
return lbx->nfiles;
}
+int lbx_stat(struct lbx_state *lbx, size_t index, struct lbx_statbuf *buf)
+{
+ static char str[256]; /* FIXME */
+
+ if (index >= lbx->nfiles) {
+ buf->name = NULL;
+ lbx_errno = LBX_ERANGE;
+ return -1;
+ }
+
+ snprintf(str, sizeof str, "%s.%03d", lbx->name, index);
+ buf->name = str;
+ buf->size = lbx->offsets[index+1] - lbx->offsets[index];
+ return 0;
+}
+
+/* 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)
+{
+ 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;
+ }
+ }
+ } else {
+ lbx_errno = -errno;
+ return -1;
+ }
+ return 0;
+}
+
+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;
+
+ assert(lbx->f);
+
+ if (_lbx_fseek(lbx, base) == -1)
+ return 0;
+
+ while (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;
+ break;
+ }
+
+ rc = fwrite(buf, 1, amt, of);
+ written += rc;
+ if (rc < amt) {
+ lbx_errno = -errno;
+ break;
+ }
+ }
+
+ 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);
}
case LBX_ESUCCESS: return "Success";
case LBX_EMAGIC: return "Bad magic number";
case LBX_EEOF: return "Unexpected end-of-file";
+ case LBX_ERANGE: return "Index out of range";
}
return "Unknown error";
projects / liblbx.git / blobdiff