X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=src%2Fresource.c;h=5237b88a37fd646613770df5768e3f56625cd2ab;hb=f3e97b29c4a8c564d54b0fd11cd43a9b4cd6a8ad;hp=7a5d1718a631cae9b24c194b531850bacf7de8cb;hpb=062465170ddb4520ca6fbc64a0f6e27e786de101;p=wimlib diff --git a/src/resource.c b/src/resource.c index 7a5d1718..5237b88a 100644 --- a/src/resource.c +++ b/src/resource.c @@ -38,6 +38,10 @@ #include #include +#ifdef HAVE_ALLOCA_H +# include +#endif + /* Write @n bytes from @buf to the file descriptor @fd, retrying on internupt * and on short writes. * @@ -90,10 +94,13 @@ full_read(int fd, void *buf, size_t n) * Returns zero on success, nonzero on failure. */ static int -read_compressed_resource(FILE *fp, u64 resource_compressed_size, +read_compressed_resource(FILE *fp, + u64 resource_compressed_size, u64 resource_uncompressed_size, - u64 resource_offset, int resource_ctype, - u64 len, u64 offset, + u64 resource_offset, + int resource_ctype, + u64 len, + u64 offset, consume_data_callback_t cb, void *ctx_or_buf) { @@ -122,7 +129,8 @@ read_compressed_resource(FILE *fp, u64 resource_compressed_size, * follows the chunk table and therefore must have an offset of 0. */ - /* Calculate how many chunks the resource conists of in its entirety. */ + /* Calculate how many chunks the resource consists of in its entirety. + * */ u64 num_chunks = (resource_uncompressed_size + WIM_CHUNK_SIZE - 1) / WIM_CHUNK_SIZE; /* As mentioned, the first chunk has no entry in the chunk table. */ @@ -149,9 +157,22 @@ read_compressed_resource(FILE *fp, u64 resource_compressed_size, if (end_chunk != num_chunks - 1) num_needed_chunks++; - /* Declare the chunk table. It will only contain offsets for the chunks - * that are actually needed for this read. */ - u64 chunk_offsets[num_needed_chunks]; + /* Allocate the chunk table. It will only contain offsets for the + * chunks that are actually needed for this read. */ + u64 *chunk_offsets; + bool chunk_offsets_malloced; + if (num_needed_chunks < 1000) { + chunk_offsets = alloca(num_needed_chunks * sizeof(u64)); + chunk_offsets_malloced = false; + } else { + chunk_offsets = malloc(num_needed_chunks * sizeof(u64)); + if (!chunk_offsets) { + ERROR("Failed to allocate chunk table " + "with %"PRIu64" entries", num_needed_chunks); + return WIMLIB_ERR_NOMEM; + } + chunk_offsets_malloced = true; + } /* Set the implicit offset of the first chunk if it is included in the * needed chunks. @@ -193,28 +214,28 @@ read_compressed_resource(FILE *fp, u64 resource_compressed_size, /* Number of bytes we need to read from the chunk table. */ size_t size = num_needed_chunk_entries * chunk_entry_size; - { - u8 chunk_tab_buf[size]; + /* Read the raw data into the end of the chunk_offsets array to + * avoid allocating another array. */ + void *chunk_tab_buf = (void*)&chunk_offsets[num_needed_chunks] - size; - if (fread(chunk_tab_buf, 1, size, fp) != size) - goto read_error; + if (fread(chunk_tab_buf, 1, size, fp) != size) + goto read_error; - /* Now fill in chunk_offsets from the entries we have read in - * chunk_tab_buf. */ + /* Now fill in chunk_offsets from the entries we have read in + * chunk_tab_buf. */ - u64 *chunk_tab_p = chunk_offsets; - if (start_chunk == 0) - chunk_tab_p++; + u64 *chunk_tab_p = chunk_offsets; + if (start_chunk == 0) + chunk_tab_p++; - if (chunk_entry_size == 4) { - u32 *entries = (u32*)chunk_tab_buf; - while (num_needed_chunk_entries--) - *chunk_tab_p++ = le32_to_cpu(*entries++); - } else { - u64 *entries = (u64*)chunk_tab_buf; - while (num_needed_chunk_entries--) - *chunk_tab_p++ = le64_to_cpu(*entries++); - } + if (chunk_entry_size == 4) { + u32 *entries = (u32*)chunk_tab_buf; + while (num_needed_chunk_entries--) + *chunk_tab_p++ = le32_to_cpu(*entries++); + } else { + u64 *entries = (u64*)chunk_tab_buf; + while (num_needed_chunk_entries--) + *chunk_tab_p++ = le64_to_cpu(*entries++); } /* Done with the chunk table now. We must now seek to the first chunk @@ -226,10 +247,11 @@ read_compressed_resource(FILE *fp, u64 resource_compressed_size, goto read_error; /* Pointer to current position in the output buffer for uncompressed - * data. */ + * data. Alternatively, if using a callback function, we repeatedly + * fill a temporary buffer to feed data into the callback function. */ u8 *out_p; if (cb) - out_p = alloca(32768); + out_p = alloca(WIM_CHUNK_SIZE); else out_p = ctx_or_buf; @@ -341,7 +363,8 @@ read_compressed_resource(FILE *fp, u64 resource_compressed_size, } if (cb) { /* Feed the data to the callback function */ - ret = cb(out_p, partial_chunk_size, ctx_or_buf); + ret = cb(out_p + start_offset, + partial_chunk_size, ctx_or_buf); if (ret) goto out; } else { @@ -355,6 +378,8 @@ read_compressed_resource(FILE *fp, u64 resource_compressed_size, ret = 0; out: + if (chunk_offsets_malloced) + FREE(chunk_offsets); return ret; read_error: @@ -512,7 +537,7 @@ read_partial_wim_resource(const struct wim_lookup_table_entry *lte, wim = lte->wim; - if (flags & WIMLIB_RESOURCE_FLAG_MULTITHREADED) { + if (flags & WIMLIB_RESOURCE_FLAG_THREADSAFE_READ) { wim_fp = wim_get_fp(wim); if (!wim_fp) { ret = -1; @@ -571,7 +596,7 @@ read_error: ERROR_WITH_ERRNO("Error reading data from WIM"); ret = WIMLIB_ERR_READ; out_release_fp: - if (flags & WIMLIB_RESOURCE_FLAG_MULTITHREADED) + if (flags & WIMLIB_RESOURCE_FLAG_THREADSAFE_READ) ret |= wim_release_fp(wim, wim_fp); out: if (ret) { @@ -588,7 +613,7 @@ read_partial_wim_resource_into_buf(const struct wim_lookup_table_entry *lte, bool threadsafe) { return read_partial_wim_resource(lte, size, NULL, buf, - threadsafe ? WIMLIB_RESOURCE_FLAG_MULTITHREADED : 0, + threadsafe ? WIMLIB_RESOURCE_FLAG_THREADSAFE_READ : 0, offset); } @@ -691,10 +716,12 @@ typedef int (*read_resource_prefix_handler_t)(const struct wim_lookup_table_entr * When using a callback function, it is called with chunks up to 32768 bytes in * size until the resource is exhausted. * - * If the resource is located in a WIM file, @flags can be - * WIMLIB_RESOURCE_FLAG_MULTITHREADED if it must be safe to access the resource - * concurrently by multiple threads, or WIMLIB_RESOURCE_FLAG_RAW if the raw - * compressed data is to be supplied instead of the uncompressed data. + * If the resource is located in a WIM file, @flags can be: + * * WIMLIB_RESOURCE_FLAG_THREADSAFE_READ if it must be safe to access the resource + * concurrently by multiple threads. + * * WIMLIB_RESOURCE_FLAG_RAW if the raw compressed data is to be supplied + * instead of the uncompressed data. + * Otherwise, the @flags are ignored. */ int read_resource_prefix(const struct wim_lookup_table_entry *lte, @@ -728,7 +755,7 @@ read_full_resource_into_buf(const struct wim_lookup_table_entry *lte, return read_resource_prefix(lte, wim_resource_size(lte), NULL, buf, - thread_safe ? WIMLIB_RESOURCE_FLAG_MULTITHREADED : 0); + thread_safe ? WIMLIB_RESOURCE_FLAG_THREADSAFE_READ : 0); } struct extract_ctx {