| /* |
| * Copyright © 2014 Intel Corporation |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| */ |
| |
| #pragma once |
| #ifndef BLOB_H |
| #define BLOB_H |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| #include <stdbool.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| /* The blob functions implement a simple, low-level API for serializing and |
| * deserializing. |
| * |
| * All objects written to a blob will be serialized directly, (without any |
| * additional meta-data to describe the data written). Therefore, it is the |
| * caller's responsibility to ensure that any data can be read later, (either |
| * by knowing exactly what data is expected, or by writing to the blob |
| * sufficient meta-data to describe what has been written). |
| * |
| * A blob is efficient in that it dynamically grows by doubling in size, so |
| * allocation costs are logarithmic. |
| */ |
| |
| struct blob { |
| /* The data actually written to the blob. */ |
| uint8_t *data; |
| |
| /** Number of bytes that have been allocated for \c data. */ |
| size_t allocated; |
| |
| /** The number of bytes that have actual data written to them. */ |
| size_t size; |
| }; |
| |
| /* When done reading, the caller can ensure that everything was consumed by |
| * checking the following: |
| * |
| * 1. blob->current should be equal to blob->end, (if not, too little was |
| * read). |
| * |
| * 2. blob->overrun should be false, (otherwise, too much was read). |
| */ |
| struct blob_reader { |
| uint8_t *data; |
| uint8_t *end; |
| uint8_t *current; |
| bool overrun; |
| }; |
| |
| /** |
| * Create a new, empty blob, belonging to \mem_ctx. |
| * |
| * \return The new blob, (or NULL in case of allocation failure). |
| */ |
| struct blob * |
| blob_create (void *mem_ctx); |
| |
| /** |
| * Add some unstructured, fixed-size data to a blob. |
| * |
| * \return True unless allocation failed. |
| */ |
| bool |
| blob_write_bytes (struct blob *blob, const void *bytes, size_t to_write); |
| |
| /** |
| * Reserve space in \blob for a number of bytes. |
| * |
| * Space will be allocated within the blob for these byes, but the bytes will |
| * be left uninitialized. The caller is expected to use the return value to |
| * write directly (and immediately) to these bytes. |
| * |
| * \note The return value is valid immediately upon return, but can be |
| * invalidated by any other call to a blob function. So the caller should call |
| * blob_reserve_byes immediately before writing through the returned pointer. |
| * |
| * This function is intended to be used when interfacing with an existing API |
| * that is not aware of the blob API, (so that blob_write_bytes cannot be |
| * called). |
| * |
| * \return A pointer to space allocated within \blob to which \to_write bytes |
| * can be written, (or NULL in case of any allocation error). |
| */ |
| uint8_t * |
| blob_reserve_bytes (struct blob *blob, size_t to_write); |
| |
| /** |
| * Overwrite some data previously written to the blob. |
| * |
| * Writes data to an existing portion of the blob at an offset of \offset. |
| * This data range must have previously been written to the blob by one of the |
| * blob_write_* calls. |
| * |
| * For example usage, see blob_overwrite_uint32 |
| * |
| * \return True unless the requested offset or offset+to_write lie outside |
| * the current blob's size. |
| */ |
| bool |
| blob_overwrite_bytes (struct blob *blob, |
| size_t offset, |
| const void *bytes, |
| size_t to_write); |
| |
| /** |
| * Add a uint32_t to a blob. |
| * |
| * \note This function will only write to a uint32_t-aligned offset from the |
| * beginning of the blob's data, so some padding bytes may be added to the |
| * blob if this write follows some unaligned write (such as |
| * blob_write_string). |
| * |
| * \return True unless allocation failed. |
| */ |
| bool |
| blob_write_uint32 (struct blob *blob, uint32_t value); |
| |
| /** |
| * Overwrite a uint32_t previously written to the blob. |
| * |
| * Writes a uint32_t value to an existing portion of the blob at an offset of |
| * \offset. This data range must have previously been written to the blob by |
| * one of the blob_write_* calls. |
| * |
| * |
| * The expected usage is something like the following pattern: |
| * |
| * size_t offset; |
| * |
| * offset = blob->size; |
| * blob_write_uint32 (blob, 0); // placeholder |
| * ... various blob write calls, writing N items ... |
| * blob_overwrite_uint32 (blob, offset, N); |
| * |
| * \return True unless the requested position or position+to_write lie outside |
| * the current blob's size. |
| */ |
| bool |
| blob_overwrite_uint32 (struct blob *blob, |
| size_t offset, |
| uint32_t value); |
| |
| /** |
| * Add a uint64_t to a blob. |
| * |
| * \note This function will only write to a uint64_t-aligned offset from the |
| * beginning of the blob's data, so some padding bytes may be added to the |
| * blob if this write follows some unaligned write (such as |
| * blob_write_string). |
| * |
| * \return True unless allocation failed. |
| */ |
| bool |
| blob_write_uint64 (struct blob *blob, uint64_t value); |
| |
| /** |
| * Add an intptr_t to a blob. |
| * |
| * \note This function will only write to an intptr_t-aligned offset from the |
| * beginning of the blob's data, so some padding bytes may be added to the |
| * blob if this write follows some unaligned write (such as |
| * blob_write_string). |
| * |
| * \return True unless allocation failed. |
| */ |
| bool |
| blob_write_intptr (struct blob *blob, intptr_t value); |
| |
| /** |
| * Add a NULL-terminated string to a blob, (including the NULL terminator). |
| * |
| * \return True unless allocation failed. |
| */ |
| bool |
| blob_write_string (struct blob *blob, const char *str); |
| |
| /** |
| * Start reading a blob, (initializing the contents of \blob for reading). |
| * |
| * After this call, the caller can use the various blob_read_* functions to |
| * read elements from the data array. |
| * |
| * For all of the blob_read_* functions, if there is insufficient data |
| * remaining, the functions will do nothing, (perhaps returning default values |
| * such as 0). The caller can detect this by noting that the blob_reader's |
| * current value is unchanged before and after the call. |
| */ |
| void |
| blob_reader_init (struct blob_reader *blob, uint8_t *data, size_t size); |
| |
| /** |
| * Read some unstructured, fixed-size data from the current location, (and |
| * update the current location to just past this data). |
| * |
| * \note The memory returned belongs to the data underlying the blob reader. The |
| * caller must copy the data in order to use it after the lifetime of the data |
| * underlying the blob reader. |
| * |
| * \return The bytes read (see note above about memory lifetime). |
| */ |
| void * |
| blob_read_bytes (struct blob_reader *blob, size_t size); |
| |
| /** |
| * Read some unstructured, fixed-size data from the current location, copying |
| * it to \dest (and update the current location to just past this data) |
| */ |
| void |
| blob_copy_bytes (struct blob_reader *blob, uint8_t *dest, size_t size); |
| |
| /** |
| * Read a uint32_t from the current location, (and update the current location |
| * to just past this uint32_t). |
| * |
| * \note This function will only read from a uint32_t-aligned offset from the |
| * beginning of the blob's data, so some padding bytes may be skipped. |
| * |
| * \return The uint32_t read |
| */ |
| uint32_t |
| blob_read_uint32 (struct blob_reader *blob); |
| |
| /** |
| * Read a uint64_t from the current location, (and update the current location |
| * to just past this uint64_t). |
| * |
| * \note This function will only read from a uint64_t-aligned offset from the |
| * beginning of the blob's data, so some padding bytes may be skipped. |
| * |
| * \return The uint64_t read |
| */ |
| uint64_t |
| blob_read_uint64 (struct blob_reader *blob); |
| |
| /** |
| * Read an intptr_t value from the current location, (and update the |
| * current location to just past this intptr_t). |
| * |
| * \note This function will only read from an intptr_t-aligned offset from the |
| * beginning of the blob's data, so some padding bytes may be skipped. |
| * |
| * \return The intptr_t read |
| */ |
| intptr_t |
| blob_read_intptr (struct blob_reader *blob); |
| |
| /** |
| * Read a NULL-terminated string from the current location, (and update the |
| * current location to just past this string). |
| * |
| * \note The memory returned belongs to the data underlying the blob reader. The |
| * caller must copy the string in order to use the string after the lifetime |
| * of the data underlying the blob reader. |
| * |
| * \return The string read (see note above about memory lifetime). However, if |
| * there is no NULL byte remaining within the blob, this function returns |
| * NULL. |
| */ |
| char * |
| blob_read_string (struct blob_reader *blob); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* BLOB_H */ |