<div dir="ltr"> <div class="gmail_extra"> <div class="gmail_quote">On Fri, Dec 12, 2014 at 2:43 PM, Carl Worth <<a href="mailto:cworth@cworth.org" target="_blank">cworth@cworth.org</a>> wrote:<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">This new interface allows for writing a series of objects to a chunk of memory (a "blob").. The allocated memory is maintained within the blob itself, (and re-allocated by doubling when necessary). There are also functions for reading objects from a blob as well. If code attempts to read beyond the available memory, the read functions return 0 values (or its moral equivalent) without reading past the allocated memory. Once the caller is done with the reads, it can check blob->overrun to ensure whether any invalid values were previously returned due to attempts to read too far. --- Jason, This second revision of my patch is in response to your review. I went to move the align_blob_reader function down by all the other blob_reader functions, but I decided not to. You had a concern about the alignment code, and it it's wrong then both align_blob() and align_blob_reader() will need to be fixed. So it seems useful to me to keep them close to each other. -Carl src/glsl/Makefile.sources | 3 +- src/glsl/blob.c | 295 ++++++++++++++++++++++++++++++++++++++++++++++ src/glsl/blob.h | 245 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 542 insertions(+), 1 deletion(-) create mode 100644 src/glsl/blob.c create mode 100644 src/glsl/blob.h diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources index 676fa0d..875e4bf 100644 --- a/src/glsl/Makefile.sources +++ b/src/glsl/Makefile.sources @@ -105,7 +105,8 @@ LIBGLSL_FILES = \ $(GLSL_SRCDIR)/opt_swizzle_swizzle.cpp \ $(GLSL_SRCDIR)/opt_tree_grafting.cpp \ $(GLSL_SRCDIR)/opt_vectorize.cpp \ - $(GLSL_SRCDIR)/s_expression.cpp + $(GLSL_SRCDIR)/s_expression.cpp \ + $(GLSL_SRCDIR)/blob.c # glsl_compiler diff --git a/src/glsl/blob.c b/src/glsl/blob.c new file mode 100644 index 0000000..75d3cda --- /dev/null +++ b/src/glsl/blob.c @@ -0,0 +1,295 @@ +/* + * Copyright © 2014 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a <div><div class="h5">+ * 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. + */ + +#include <string.h> + +#include "main/macros.h" +#include "util/ralloc.h" +#include "blob.h" + +#define BLOB_INITIAL_SIZE 4096 + +/* Ensure that \blob will be able to fit an additional object of size + * \additional. The growing (if any) will occur by doubling the existing + * allocation. + */ +static bool +grow_to_fit (struct blob *blob, size_t additional) +{ + size_t to_allocate; + uint8_t *new_data; + + if (blob->size + additional <= blob->allocated) + return true; + </div></div>+ if (blob->allocated == 0) + to_allocate = BLOB_INITIAL_SIZE; + else + to_allocate = MAX2(blob->allocated * 2, additional); </blockquote><div> </div><div>Should be MAX2(blob->allocated * 2, blob->size + additional) </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> + + new_data = reralloc_size(blob, blob->data, to_allocate); + if (new_data == NULL) + return false; + + blob->data = new_data; + blob->allocated = to_allocate; + + return true; +} + +/* Align the blob->size so that reading or writing a value at (blob->data + + * blob->size) will result in an access aligned to a granularity of \alignment + * bytes. + * + * \return True unless allocation fails + */ +static bool +align_blob (struct blob *blob, size_t alignment) +{ + size_t new_size; + + new_size = ALIGN(blob->size, alignment); + + if (! grow_to_fit (blob, new_size - blob->size)) + return false; + + blob->size = new_size; + + return true; +} + +static void +align_blob_reader (struct blob_reader *blob, size_t alignment) +{ + blob->current = blob->data + ALIGN(blob->current - blob->data, alignment); <div><div class="h5">+} + +struct blob * +blob_create (void *mem_ctx) +{ + struct blob *blob; + + blob = ralloc(mem_ctx, struct blob); + if (blob == NULL) + return NULL; + + blob->data = NULL; + blob->allocated = 0; + blob->size = 0; + + return blob; +} + +bool +blob_write_bytes (struct blob *blob, const void *bytes, size_t to_write) +{ + if (! grow_to_fit (blob, to_write)) + return false; + + memcpy (blob->data + blob->size, bytes, to_write); + blob->size += to_write; + + return true; +} + +uint8_t * +blob_reserve_bytes (struct blob *blob, size_t to_write) +{ + uint8_t *ret; + + if (! grow_to_fit (blob, to_write)) + return NULL; + + ret = blob->data + blob->size; + blob->size += to_write; + + return ret; +} + +bool +blob_write_uint32 (struct blob *blob, uint32_t value) +{ + align_blob(blob, sizeof(value)); + + return blob_write_bytes(blob, &value, sizeof(value)); +} + +bool +blob_write_uint64 (struct blob *blob, uint64_t value) +{ + align_blob(blob, sizeof(value)); + + return blob_write_bytes(blob, &value, sizeof(value)); +} + +bool +blob_write_intptr (struct blob *blob, intptr_t value) +{ + align_blob(blob, sizeof(value)); + + return blob_write_bytes(blob, &value, sizeof(value)); +} + +bool +blob_write_string (struct blob *blob, const char *str) +{ + return blob_write_bytes(blob, str, strlen(str) + 1); +} + </div></div>+void +blob_reader_init (struct blob_reader *blob, uint8_t *data, size_t size) +{ + blob->data = data; + blob->end = data + size; + blob->current = data; + blob->overrun = false; +} + +/* Check that an object of size \size can be read from this blob. + * + * If not, set blob->overrun to indicate that we attempted to read too far. + */ +static bool +ensure_can_read (struct blob_reader *blob, size_t size) +{ + if (blob->current < blob->end && blob->end - blob->current >= size) + return true; + + blob->overrun = true; + + return false; +} + +void * +blob_read_bytes (struct blob_reader *blob, size_t size) +{ + void *ret; + + if (! ensure_can_read (blob, size)) + return NULL; + + ret = blob->current; + + blob->current += size; + + return ret; +} + +void +blob_copy_bytes (struct blob_reader *blob, uint8_t *dest, size_t size) +{ + uint8_t *bytes; + + bytes = blob_read_bytes (blob, size); + if (bytes == NULL) + return; + + memcpy (dest, bytes, size); +} + +uint32_t +blob_read_uint32 (struct blob_reader *blob) +{ + uint32_t ret; + int size = sizeof(ret); + + align_blob_reader(blob, size); + + if (! ensure_can_read(blob, size)) + return 0; + + ret = *((uint32_t*) blob->current); + + blob->current += size; + + return ret; +} + +uint64_t +blob_read_uint64 (struct blob_reader *blob) +{ + uint64_t ret; + int size = sizeof(ret); + + align_blob_reader(blob, size); + + if (! ensure_can_read(blob, size)) + return 0; + + ret = *((uint64_t*) blob->current); + + blob->current += size; + + return ret; +} + +intptr_t +blob_read_intptr (struct blob_reader *blob) +{ + intptr_t ret; + int size = sizeof(ret); + + align_blob_reader(blob, size); + + if (! ensure_can_read(blob, size)) + return 0; + + ret = *((intptr_t *) blob->current); + + blob->current += size; + + return ret; +} </blockquote><div> Something to tuck in the back of your brain in case you have a need to grow this datastructure: The above write functions could be generated with three invocations of a macro that takes a function name and a type. That would prevent copy-and-paste typos. For only 3 functions, this probably isn't worth it. However, if we ever expand this to also include uint8, uint16, float, and double, that might not be a bad idea. Same for the writing functions. </div><div>Other than the couple comments here and the alignment thing (different e-mail). Reviewed-by: Jason Ekstrand <<a href="mailto:jason.ekstrand@intel.com">jason.ekstrand@intel.com</a>> </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> + +char * +blob_read_string (struct blob_reader *blob) +{ + int size; + char *ret; + uint8_t *nul; + + /* If we're already at the end, then this is an overrun. */ + if (blob->current >= blob->end) { + blob->overrun = true; + return NULL; + } + + /* Similarly, if there is no zero byte in the data remaining in this blob, + * we also consider that an overrun. */ + nul = memchr (blob->current, 0, blob->end - blob->current); + + if (nul == NULL) { + blob->overrun = true; + return NULL; + } + + size = nul - blob->current + 1; + + assert (ensure_can_read(blob, size)); + + ret = (char *) blob->current; + + blob->current += size; + + return ret; +} diff --git a/src/glsl/blob.h b/src/glsl/blob.h new file mode 100644 index 0000000..8d0d959 --- /dev/null +++ b/src/glsl/blob.h @@ -0,0 +1,245 @@ +/* + * Copyright © 2014 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a <div><div class="h5">+ * 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 <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. + */ + +/* The allocated size is the number of bytes that have actually been allocated + * for the "data" array, while "size" is the number of bytes actually used to + * store data. + */ +struct blob { + uint8_t *data; + size_t allocated; + size_t size; +}; + +/* When done reading, the caller can ensure that everything was consumed by + * checking the following: + * + * 1. blob->data 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); + +/** </div></div><div><div class="h5">+ * 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); + +/** + * 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, (inintializing 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. + */ </div></div>+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). + * + * 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); + <div class="HOEnZb"><div class="h5">+/** + * 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). + * + * 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 * </div></div>+blob_read_string (struct blob_reader *blob); + <div class="HOEnZb"><div class="h5">+#ifdef __cplusplus +} +#endif + +#endif /* BLOB_H */ -- 2.1.1 _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/mesa-dev" target="_blank">http://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </div></div></blockquote></div></div></div>