liblbx: Parameterise I/O functions to allow custom streams.

[liblbx.git] / src / lbx.c

diff --git a/src/lbx.c b/src/lbx.c
index fc52680c47c0a57c19fec6a074de4ff0af5f884c..4b5d7f3fe8f483c9003df780b6fa6f44fd6ba6c6 100644 (file)
--- a/src/lbx.c
+++ b/src/lbx.c
@@ -42,10 +42,9 @@ int lbx_errno = 0;
 struct lbx_state {
        const char *name;
 
-       unsigned char *mem;
-       size_t memsize;
-       FILE *f;
-       long foff;
+       const struct lbx_file_ops *fops;
+       int (*dtor)(void *handle);
+       void *f;
 
        uint16_t nfiles;
        uint32_t offsets[];
@@ -76,12 +75,13 @@ static struct lbx_state *lbx_init(unsigned char hdr[static LBX_HDR_SIZE])
        return lbx;
 }
 
-struct lbx_state *lbx_fopen(FILE *f, const char *name)
+struct lbx_state *lbx_open(void *f, const struct lbx_file_ops *fops,
+                           int (*destructor)(void *), const char *name)
 {
        unsigned char hdr_buf[LBX_HDR_SIZE];
        struct lbx_state *lbx;
 
-       if (fread(hdr_buf, 1, sizeof hdr_buf, f) != sizeof hdr_buf) {
+       if (fops->read(hdr_buf, sizeof hdr_buf, f) != sizeof hdr_buf) {
                lbx_errno = -errno;
                return NULL;
        }
@@ -90,79 +90,31 @@ struct lbx_state *lbx_fopen(FILE *f, const char *name)
        if (!lbx)
                return NULL;
 
+       lbx->dtor = destructor;
        lbx->name = name;
+       lbx->fops = fops;
        lbx->f    = f;
-       lbx->foff = sizeof hdr_buf;
 
        for (unsigned i = 0; i <= lbx->nfiles; i++) {
                unsigned char buf[4];
 
-               if (fread(buf, 1, sizeof buf, f) != sizeof buf) {
+               if (fops->read(buf, sizeof buf, f) != sizeof buf) {
                        lbx_errno = -errno;
-                       if (feof(f))
+                       if (fops->eof(f))
                                lbx_errno = LBX_EEOF;
                        free(lbx);
                        return NULL;
                }
 
                lbx->offsets[i] = unpack_32_le(buf);
-               lbx->foff += sizeof buf;
        }
 
        return lbx;
 }
 
-static int _lbx_memcpy(void *dest, struct lbx_state *src, size_t size)
+struct lbx_state *lbx_fopen(FILE *f, const char *name)
 {
-       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;
+       return lbx_open(f, &lbx_default_fops, NULL, name);
 }
 
 size_t lbx_numfiles(struct lbx_state *lbx)
@@ -186,21 +138,6 @@ int lbx_stat(struct lbx_state *lbx, size_t index, struct lbx_statbuf *buf)
        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)
 {
@@ -209,17 +146,18 @@ _lbx_fextract(struct lbx_state *lbx, size_t base, size_t len, FILE *of)
 
        assert(lbx->f);
 
-       if (_lbx_fseek(lbx->f, &lbx->foff, base) == -1)
+       if (lbx->fops->seek(lbx->f, base, SEEK_SET) != 0) {
+               lbx_errno = -errno;
                return 0;
+       }
        
        while (len) {
                size_t amt = MIN(len, sizeof buf);
 
-               rc = fread(buf, 1, amt, lbx->f);
-               lbx->foff += rc;
+               rc = lbx->fops->read(buf, amt, lbx->f);
                len -= rc;
                if (rc < amt) {
-                       if (feof(lbx->f)) lbx_errno = LBX_EEOF;
+                       if (lbx->fops->eof(lbx->f)) lbx_errno = LBX_EEOF;
                        else lbx_errno = -errno;
                        break;
                }
@@ -246,9 +184,6 @@ size_t lbx_extract(struct lbx_state *lbx, size_t index, FILE *of)
        
        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);
 }
 
@@ -256,13 +191,10 @@ int lbx_close(struct lbx_state *lbx)
 {
        int rc = 0;
 
-       if (!lbx)
-               return 0;
-
-       if (lbx->f)
-               rc = fclose(lbx->f);
-
+       if (lbx && lbx->dtor)
+               rc = lbx->dtor(lbx->f);
        free(lbx);
+
        return rc;
 }