Shally Verma(1234sv) replied on github web page:

include/odp/api/spec/comp.h
line 530
@@ -0,0 +1,873 @@
+/* Copyright (c) 2017, Linaro Limited
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier:    BSD-3-Clause
+ */
+
+/**
+ * @file
+ *
+ * ODP Compression
+ */
+
+#ifndef ODP_API_COMP_H_
+#define ODP_API_COMP_H_
+
+#include <odp/visibility_begin.h>
+#include <odp/api/support.h>
+#include <odp/api/packet.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** @defgroup odp_compression ODP COMP
+ *  ODP Compression is an API set to do compression+hash or decompression+hash
+ *  operations on data. Hash is calculated on plaintext.
+ *
+ *  if opcode = ODP_COMP_COMPRESS, then it will apply hash and then compress,
+ *  if opcode = ODP_COMP_DECOMPRESS, then it will decompress and then apply
+ *  hash.
+ *  Independent hash-only operations are not supported. Implementation should
+ *  perform hash along with valid compression algo.
+ *  Macros, enums, types and operations to utilize compression interface.
+ *  @{
+ */
+
+/**
+ * @def ODP_COMP_SESSION_INVALID
+ * Invalid session handle
+ */
+
+/**
+ * @typedef odp_comp_session_t
+ * Compression/Decompression session handle
+ */
+
+/**
+ * Compression API operation mode
+ */
+typedef enum {
+       /** Synchronous, return results immediately */
+       ODP_COMP_SYNC,
+       /** Asynchronous, return results via event queue */
+       ODP_COMP_ASYNC
+} odp_comp_op_mode_t;
+
+/**
+ * Comp API operation type.
+ *
+ */
+typedef enum {
+       /** Compress */
+       ODP_COMP_OP_COMPRESS,
+       /** Decompress */
+       ODP_COMP_OP_DECOMPRESS
+} odp_comp_op_t;
+
+/**
+ * Comp API hash algorithm
+ *
+ */
+typedef enum {
+       /** ODP_COMP_HASH_ALG_NONE - No hash algorithm selected. */
+       ODP_COMP_HASH_ALG_NONE,
+       /** ODP_COMP_HASH_ALG_SHA1 - SHA-1 hash algorithm. */
+       ODP_COMP_HASH_ALG_SHA1,
+       /** ODP_COMP_HASH_ALG_SHA256 - SHA-2 hash algorithm
+        * 256-bit digest length.
+        */
+       ODP_COMP_HASH_ALG_SHA256
+} odp_comp_hash_alg_t;
+
+/**
+ * Comp API compression algorithm
+ *
+ */
+typedef enum {
+       /** No algorithm specified.
+        * Means no compression, output == input.
+        * if provided, no operation (compression/decompression or hash)
+        * applied on input. Added for testing purpose.
+        */
+       ODP_COMP_ALG_NULL,
+       /** DEFLATE - RFC1951 */
+       ODP_COMP_ALG_DEFLATE,
+       /** ZLIB - RFC1950 */
+       ODP_COMP_ALG_ZLIB,
+       /** LZS */
+       ODP_COMP_ALG_LZS
+} odp_comp_alg_t;
+
+/**
+ * Comp API session creation return code
+ *
+ */
+typedef enum {
+       /** Session created */
+       ODP_COMP_SES_CREATE_ERR_NONE,
+       /** Creation failed, no resources */
+       ODP_COMP_SES_CREATE_ERR_ENOMEM,
+       /** Creation failed, bad compression params */
+       ODP_COMP_SES_CREATE_ERR_INV_COMP,
+       /** Creation failed, bad hash params */
+       ODP_COMP_SES_CREATE_ERR_INV_HASH,
+       /** Creation failed,requested configuration not supported*/
+       ODP_COMP_SES_CREATE_ERR_NOT_SUPPORTED
+} odp_comp_ses_create_err_t;
+
+/**
+ * Comp API operation return codes
+ *
+ */
+typedef enum {
+       /** Operation completed successfully*/
+       ODP_COMP_ERR_NONE,
+       /** Operation paused due to insufficient output buffer.
+        *
+        * This is not an error condition. On seeing this situation,
+        * Implementation should maintain context of in-progress operation and
+        * application should call packet processing API again with valid
+        * output buffer but no other alteration to operation params
+        * (odp_comp_op_param_t).
+        *
+        * if using async mode, application should either make sure to
+        * provide sufficient output buffer size OR maintain relevant
+        * context (or ordering) information with respect to each input packet
+        * en-queued for processing.
+        *
+        */
+       ODP_COMP_ERR_OUT_OF_SPACE,
+       /** Invalid user data pointers */
+       ODP_COMP_ERR_DATA_PTR,
+       /** Invalid input data size */
+       ODP_COMP_ERR_DATA_SIZE,
+       /**  Compression Algo failure */
+       ODP_COMP_ERR_ALGO_FAIL,
+       /** Error if operation has been requested in an invalid state */
+       ODP_COMP_ERR_INV_STATE,
+       /** Error if API does not support any of the operational parameter. */
+       ODP_COMP_ERR_NOT_SUPPORTED,
+       /** Error if session is invalid. */
+       ODP_COMP_ERR_INV_SESS
+} odp_comp_err_t;
+
+/**
+ * Comp API enumeration for preferred compression level/speed. Applicable
+ * only for compression operation not decompression.
+ * Value provided defines a trade-off between speed and compression ratio.
+ *
+ * If compression level == ODP_COMP_LEVEL_MIN, output will be produced at
+ * fastest possible rate,
+ *
+ * If compression level == ODP_COMP_LEVEL_MAX, output will be highest possible
+ * compression,
+ *
+ * compression level == ODP_COMP_LEVEL_DEFAULT means implementation will use
+ * its default choice of compression level.
+ *
+ */
+typedef enum {
+       /* Use implementation default */
+       ODP_COMP_LEVEL_DEFAULT = 0,
+       /** Minimum compression (fastest in speed) */
+       ODP_COMP_LEVEL_MIN,
+       /** Maximum compression (slowest in speed) */
+       ODP_COMP_LEVEL_MAX,
+} odp_comp_level_t;
+
+/**
+ * Comp API enumeration for huffman encoding. Valid for compression operation.
+ *
+ */
+typedef enum {
+       /** use implementation default to choose between compression codes  */
+       ODP_COMP_HUFFMAN_CODE_DEFAULT = 0,
+       /** use fixed huffman codes */
+       ODP_COMP_HUFFMAN_CODE_FIXED,
+       /** use dynamic huffman coding */
+       ODP_COMP_HUFFMAN_CODE_DYNAMIC,
+} odp_comp_huffman_code_t;
+
+/**
+ * Hash algorithms in a bit field structure
+ *
+ */
+typedef union odp_comp_hash_algos_t {
+       /** hash algorithms */
+       struct {
+               /** ODP_COMP_HASH_ALG_SHA1 */
+               uint32_t sha1  : 1;
+
+               /** ODP_COMP_HASH_ALG_SHA256 */
+               uint32_t sha256 : 1;
+
+       } bit;
+
+       /** All bits of the bit field structure
+        *
+        * This field can be used to set/clear all flags, or bitwise
+        * operations over the entire structure.
+        */
+       uint32_t all_bits;
+} odp_comp_hash_algos_t;
+
+/**
+ * Comp algorithms in a bit field structure
+ *
+ */
+typedef union odp_comp_algos_t {
+       /** Compression algorithms */
+       struct {
+               /** ODP_COMP_ALG_NULL */
+               uint32_t null       : 1;
+
+               /** ODP_COMP_ALG_DEFLATE */
+               uint32_t deflate    : 1;
+
+               /** ODP_COMP_ALG_ZLIB */
+               uint32_t zlib       : 1;
+
+               /** ODP_COMP_ALG_LZS */
+               uint32_t lzs        :1;
+       } bit;
+
+       /** All bits of the bit field structure
+        * This field can be used to set/clear all flags, or bitwise
+        * operations over the entire structure.
+        */
+       uint32_t all_bits;
+} odp_comp_algos_t;
+
+/**
+ * Compression Interface Capabilities
+ *
+ */
+typedef struct odp_comp_capability_t {
+       /** Maximum number of  sessions */
+       uint32_t max_sessions;
+
+       /** Supported compression algorithms */
+       odp_comp_algos_t comp_algos;
+
+       /** Supported hash algorithms. */
+       odp_comp_hash_algos_t hash_algos;
+
+       /** Support type for synchronous operation mode (ODP_COMP_SYNC).
+        *  User should set odp_comp_session_param_t:mode based on
+        *  support level as indicated by this param.
+        */
+       odp_support_t sync;
+
+       /** Support type for asynchronous operation mode (ODP_COMP_ASYNC).
+        *  User should set odp_comp_session_param_t:mode param based on
+        *  support level as indicated by this param.
+        */
+       odp_support_t async;
+} odp_comp_capability_t;
+
+/**
+ * Hash algorithm capabilities
+ *
+ */
+typedef struct odp_comp_hash_alg_capability_t {
+       /** Digest length in bytes */
+       uint32_t digest_len;
+} odp_comp_hash_alg_capability_t;
+
+/**
+ * Compression algorithm capabilities structure for each algorithm.
+ *
+ */
+typedef struct odp_comp_alg_capability_t {
+       /** Enumeration indicating algorithm support for dictionary load */
+       odp_support_t support_dict;
+
+       /** Optional Maximum length of dictionary supported
+        *  by implementation of an algorithm.
+        *
+        *  Invalid if support_dict == ODP_SUPPORT_NO.
+        *
+        *  Implementation use dictionary of length less than or equal to value
+        *  indicated by dict_len. if set to 0 and if support_dict ==
+        *  ODP_SUPPORT_YES, then implementation will use dictionary length
+        *  less than or equal to user input length in odp_comp_set_dict()
+        *  and update used dictionary length at output of the call.
+        *
+        */
+       uint32_t dict_len;
+
+       /** Maximum compression level supported by implementation of this algo.
+        * Indicates number of compression levels supported by implementation,
+        *
+        * where,
+        *
+        * 1 means fastest compression i.e. output produced at
+        * best possible speed at the expense of compression quality, and
+        *
+        * max_level means best compression i.e.output produced is best possible
+        * compressed content at the expense of speed.
+        *
+        * Example, if max_level = 4 , it means algorithm supports four levels
+        * of compression from value 1 up to 4. User can set this value from
+        * 1 (fastest compression) to 4 (best compression).
+        * See RFC1950 for an example explanation to level.
+        *
+        * Value 0 mean implementation use its default value.
+        *
+        */
+       uint32_t max_level;
+
+       /* Supported hash algorithms */
+       odp_comp_hash_algos_t hash_algo;
+} odp_comp_alg_capability_t;
+
+/**
+ * Comp API dictionary type
+ * Consists of pointer to byte buffer. length of dictionary
+ * indicated by length parameter.
+ */
+typedef struct odp_comp_dict_t {
+       /** pointer to byte array */
+       uint8_t *buf;
+       /** length of the dictionary. */
+       uint32_t len;
+} odp_comp_dict_t;
+
+/**
+ * Comp API algorithm specific parameters
+ *
+ */
+typedef struct odp_comp_algo_param_t {
+       /** struct for defining deflate algorithm parameters.
+       * Also initialized by other deflate based algorithms , ex. ZLIB
+       */
+       struct comp_alg_def_param {
+               /** compression level where
+                * ODP_COMP_LEVEL_MIN <= level <= ODP_COMP_LEVEL_MAX
+                */
+               odp_comp_level_t level;
+               /** huffman code to use */
+               odp_comp_huffman_code_t comp_code;
+       } deflate;
+
+       /** struct for defining zlib algorithm parameters.
+        */
+       struct comp_alg_zlib_param {
+                       /** deflate algo params */
+                       struct comp_alg_def_param def;
+       } zlib;
+} odp_comp_alg_param_t;
+
+ /**
+ * Comp API session creation parameters
+ *
+ */
+typedef struct odp_comp_session_param_t {
+       /** Compress vs. Decompress operation */
+       odp_comp_op_t op;
+
+       /** Sync vs Async mode
+        *
+        * When mode = ODP_COMP_SYNC, odp_comp_xxx()
+        * should be called.
+        *
+        * When mode = ODP_COMP_ASYNC, odp_comp_xxx_enq()
+        * should be called.
+        *
+        * Use odp_comp_capability() for supported mode.
+        *
+        */
+       odp_comp_op_mode_t mode;
+
+       /** Compression algorithm
+        *
+        *  Use odp_comp_capability() for supported algorithms.
+        */
+       odp_comp_alg_t comp_algo;
+
+       /** Hash algorithm
+        *
+        *  Use odp_comp_alg_capability() for supported hash algo for
+        *  compression algo given as comp_alg. Implementation should not
+        *  support hash only operation on data. output should always contain
+        *  data + hash.
+        *
+        */
+       odp_comp_hash_alg_t hash_algo;
+
+       /** parameters specific to compression */
+       odp_comp_alg_param_t algo_param;
+
+       /** Async mode completion event queue
+        *
+        * When mode = ODP_COMP_ASYNC, user should wait on ODP_EVENT_PACKET
+        * with subtype ODP_EVENT_PACKET_COMP on this queue.
+        *
+        * By default, implementation enques completion events in-order-of
+        * request submission and thus queue is considered ordered.
+        *
+        * Please note, behavior could be changed or enhanced
+        * to queue event in-order-of their completion to enable
+        * performance-oriented application to leverage hw offered parallelism.
+        * However, this will be subject to application requirement and more
+        * explicit defined use-case.
+        *
+        */
+       odp_queue_t compl_queue;
+} odp_comp_session_param_t;
+
+/**
+ * Comp API per packet operation result
+ *
+ */
+typedef struct odp_comp_packet_op_result_t {
+       /** Operation Return Code */
+       odp_comp_err_t err;
+
+       /** Output packet data range. Where,
+        *
+        *  offset = base offset within packet, current data is written at.
+        *
+        *  length = length of data written.
+        *
+        */
+       odp_packet_data_range_t out_data_range;
+} odp_comp_packet_op_result_t;
+
+/**
+ * Comp packet API per packet operation parameters
+ */
+typedef struct odp_comp_packet_op_param_t {
+       /** Session handle from creation */
+       odp_comp_session_t session;
+
+       /** Boolean indicating if current input is last chunk of data, where
+        *
+        *   true : last chunk
+        *
+        *   false: more to follow
+        *
+        * If set to true, indicates this is the last chunk of
+        * data. After processing of last chunk of data is complete i.e.
+        * call returned with any error code except ODP_COMP_ERR_OUT_OF_SPACE,
+        * implementation should move algorithm to stateless mode
+        * for next of batch of operation i.e. reset history,
+        * insert 'End of Block' marker into compressed data stream(if
+        * supported by algo).See deflate/zlib for interpretation of
+        * stateless/stateful.
+        *
+        * For stateless compressions (ex ipcomp), last should be set to 'true'
+        * for every input packet processing call.
+        *
+        * For compression + hash, digest will be available after
+        * last chunk is processed completely. In case of
+        * ODP_COMP_ERR_OUT_OF_SPACE, application should keep on calling
+        * odp_comp_xxx() API with more output buffer unless call returns
+        * with ODP_COMP_ERR_NONE or other failure code except
+        *  ODP_COMP_ERR_OUT_OF_SPACE.
+        */
+       odp_bool_t last;
+
+       /** Input data range to process */
+       odp_packet_data_range_t in_data_range;
+
+       /** Output packet data range.
+        * Indicates where processed packet will be written
+        * where length specifies,
+        * length of available packet buffer at input, and
+        * length of data written at output
+        */
+       odp_packet_data_range_t out_data_range;
+} odp_comp_packet_op_param_t;
+
+/**
+ * Query comp capabilities
+ *
+ * Output comp capabilities on success.
+ *
+ * @param[out] capa   Pointer to capability structure for output
+ *
+ * @retval 0 on success
+ * @retval <0 on failure
+ */
+int odp_comp_capability(odp_comp_capability_t *capa);
+
+/**
+ * Query supported compression algorithm capabilities
+ *
+ * Output algorithm capabilities.
+ *
+ * @param      comp     Compression algorithm
+ * @param[out] capa     Array of capability structures for output
+ * @param      num     Maximum number of capability structures to output
+ *
+ * @return Number of capability structures for the algorithm. If this is larger
+ *         than 'num', only 'num' first structures were output and application
+ *         may call the function again with a larger value of 'num'.
+ * @retval <0 on failure
+ */
+int odp_comp_alg_capability(odp_comp_alg_t comp,
+                           odp_comp_alg_capability_t capa[], int num);
+
+/**
+ * Query supported hash algorithm capabilities
+ *
+ * Outputs all supported configuration options for the algorithm.
+ *
+ * @param      hash     Hash algorithm
+ * @param[out] capa     Array of capability structures for output
+ * @param      num      Maximum number of capability structures to output
+ *
+ * @return Number of capability structures for the algorithm. If this is larger
+ *         than 'num', only 'num' first structures were output and application
+ *         may call the function again with a larger value of 'num'.
+ * @retval <0 on failure
+ */
+int odp_comp_hash_alg_capability(odp_comp_hash_alg_t hash,
+                                odp_comp_hash_alg_capability_t capa[],
+                                int num);
+


Comment:
Can this return more than one hash_alg_capa (== digest_len) per hash_alg?
>>No. ideally, an implementation should return only 1 single capability per 
>>hash algorithm. I cannot think why a valid implementation would return more 
>>than 1 capability according to capability structure we have here. 
This API signature has been retained to keep consistency with other interface 
capability API. 

> Shally Verma(1234sv) wrote:
> offset is not updated by spec as compression does not support auto-allocation 
> of packet and starts data write at given offset only. For description, I 
> rephrased it as below. 
>  "    /** Output packet data range.
>        *
>        * out_data_range.offset = offset in output packet data buffer to start
>        * write at,
>        *
>        * out_data_range.length = length of available space for output
>        * from given offset.
>        *
>        */
>> Shally Verma(1234sv) wrote:
>> Ok. 
>>> Shally Verma(1234sv) wrote:
>>> "then we should document that the value is ignored."
>>> >> Sorry, I didn't get that. You referring to which value to be ignored?
>>>> Shally Verma(1234sv) wrote:
>>>> Did you refer to note starting here " * Please note, behavior could be 
>>>> changed or enhanced........"? if yes, okay I will remove that text. Please 
>>>> confirm.
>>>>> Shally Verma(1234sv) wrote:
>>>>> accepted.
>>>>>> Shally Verma(1234sv) wrote:
>>>>>> 1.comp_algo is always set. It should be e.g. ALG_NULL by default. 
>>>>>> >> I am bit confused. Are you suggesting adding a description to "comp 
>>>>>> >> ALG_NULL+hash"? We agreed in past that " user must use crypto for 
>>>>>> >> standalone hashing and compression algo NULL is only for testing 
>>>>>> >> purpose" and current description on usage of hash and ALG_NULL abide 
>>>>>> >> that.  So, we can leave current description as is.
>>>>>> 2. What this means: "output should always contain data + hash" ? If we 
>>>>>> enable hashing, hash is always calculated. It's not optional for 
>>>>>> implementation to calculate it - right.
>>>>>> >> I will rephrase it to "output *will* always contain data + hash". 
>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>> " This should be specified at operation documentation" means which 
>>>>>>> place? user guide Or ?
>>>>>>> 
>>>>>>> Do you mean I should remove this description from here? Or 
>>>>>>> "+ *  if opcode = ODP_COMP_COMPRESS, then it will apply hash and then 
>>>>>>> compress,
>>>>>>>  + *  if opcode = ODP_COMP_DECOMPRESS, then it will decompress and then 
>>>>>>> apply
>>>>>>>  + *  hash."
>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>> First, async call can reuse sync call spec by saying: "... processes 
>>>>>>>> packets otherwise identically to odp_comp_op(), but outputs resulting 
>>>>>>>> packets as ODP_EVENT_PACKET events ...". Then the remaining text can 
>>>>>>>> concentrate on what is unique on async vs sync operation.
>>>>>>>> 
>>>>>>>> I think OUT_OF_SPACE spec might need re-thinking:
>>>>>>>> 1) user sees a partial packet (error on a received packet)
>>>>>>>> 2) implementation waits that user calls op_enq() again
>>>>>>>> 3) what input packet should be given on the new call? I think the 
>>>>>>>> previous operation already consumed the input packet which contains 
>>>>>>>> the input data for operation. Did implementation store it?
>>>>>>>> 4) how long implementation waits for new output packet to arrive from 
>>>>>>>> user, what if user don't send new output packets.
>>>>>>>> 
>>>>>>>> Async spec (and also sync) spec would be more robust if implementation 
>>>>>>>> would allocate output packets. 
>>>>>>>>  
>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>> Application does not allocate buffers but packets.
>>>>>>>>> 
>>>>>>>>> Does the partially processed packet contain valid data or not == does 
>>>>>>>>> application keep or discard the packet?
>>>>>>>>> 
>>>>>>>>> Is there any way for application to prepare large enough packet in 
>>>>>>>>> advance? E.g. a per algo capability of worst case decompression 
>>>>>>>>> ratio? Should "pkt_out = INVALID" be supported? ==> implementation 
>>>>>>>>> allocates large enough packet.
>>>>>>>>> 
>>>>>>>>> Single packet handle should **not** be defined as const.
>>>>>>>>> 
>>>>>>>>> There is out_data_range defined in both op_param_t and op_result_t. 
>>>>>>>>> Which one is updated on output? May be operation output comments 
>>>>>>>>> should be removed from op_param_t documentation.
>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>> Simply say that:
>>>>>>>>>> This operation does de/-compression in synchronous mode 
>>>>>>>>>> (ODP_COMP_SYNC).
>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>> "implementation should update length of dictionary used at output."
>>>>>>>>>>> This is too vague: either length is updated or it's not. In which 
>>>>>>>>>>> cases the update would be done and what that would mean? Also, I 
>>>>>>>>>>> assume that implementation copies the data, so that application is 
>>>>>>>>>>> free to overwrite the memory after the call. That (copies data) 
>>>>>>>>>>> should be mentioned also.
>>>>>>>>>>> 
>>>>>>>>>>> Is there a benefit on output param here, especially if it updates 
>>>>>>>>>>> only the length and not the pointer. Maybe API would be cleaner, if 
>>>>>>>>>>> also *dict is input only param (and thus const*). Function may 
>>>>>>>>>>> return e.g. number of bytes copied/used.
>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>> This can be simply
>>>>>>>>>>>> 
>>>>>>>>>>>> odp_comp_session_t odp_comp_session_create(const 
>>>>>>>>>>>> odp_comp_session_param_t *param)
>>>>>>>>>>>> 
>>>>>>>>>>>> Extra error codes may be returned through odp_errno(). Usually, we 
>>>>>>>>>>>> have not defined error codes, since it's implementation defines 
>>>>>>>>>>>> what all things can possibly go wrong, and typically application 
>>>>>>>>>>>> logic is just interested on success vs fail - not so much why we 
>>>>>>>>>>>> failed.
>>>>>>>>>>>> 
>>>>>>>>>>>> This function prototype is copy-paste from crypto API, but all 
>>>>>>>>>>>> other APIs are the type I suggested above.
>>>>>>>>>>>> 
>>>>>>>>>>>> Note: const pointer for "param"
>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>> It would be good to define default values for 
>>>>>>>>>>>>> odp_comp_session_param_t (at the type documentation). Otherwise, 
>>>>>>>>>>>>> application needs to always set every param.
>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>> Can this return more than one hash_alg_capa (== digest_len) per 
>>>>>>>>>>>>>> hash_alg? Currently, application cannot select digest length. 
>>>>>>>>>>>>>> So, what application should do if this returns more than one 
>>>>>>>>>>>>>> capa.
>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>> Is array of capabilities needed with comp algorithms? It would 
>>>>>>>>>>>>>>> be needed if user would need to select between multiple 
>>>>>>>>>>>>>>> discrete options - e.g. if only some dict_len values would make 
>>>>>>>>>>>>>>> sense (1kB, 4kB, 16kB), but nothing in between.
>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>> "where length specifies,
>>>>>>>>>>>>>>>> length of available packet buffer at input, and
>>>>>>>>>>>>>>>> length of data written at output"
>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>> This specification should be clarified. "Input" refers refers 
>>>>>>>>>>>>>>>> to out_data_range.length as operation input param and  
>>>>>>>>>>>>>>>> "output" refers to the same as operation output parameter.
>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>> In addition to length, offset may be updated at operation 
>>>>>>>>>>>>>>>> output (at least when new packet was allocated). That should 
>>>>>>>>>>>>>>>> be mentioned also.
>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>> This last chuck: 
>>>>>>>>>>>>>>>>> "In case of
>>>>>>>>>>>>>>>>> ODP_COMP_ERR_OUT_OF_SPACE, application should keep on calling
>>>>>>>>>>>>>>>>> odp_comp_xxx() API with more output buffer unless call returns
>>>>>>>>>>>>>>>>> with ODP_COMP_ERR_NONE or other failure code except
>>>>>>>>>>>>>>>>> ODP_COMP_ERR_OUT_OF_SPACE. "
>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>> Documents operation return / error codes rather than "last" 
>>>>>>>>>>>>>>>>> field usage. So, I'd remove it from here.
>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>> If only option for a stateless algorithm is true, then we 
>>>>>>>>>>>>>>>>>> should document that the value is ignored.
>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>> Typo: "enques" -> enqueues"
>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>> Remove this block text since it's speculation of what 
>>>>>>>>>>>>>>>>>>>> could be specified.
>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>> Typo: "... given as comp_alg" -> "... given as comp_algo"
>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>> There are two SHOULDs, but I think those are not needed:
>>>>>>>>>>>>>>>>>>>>> 1) comp_algo is always set. It should be e.g. ALG_NULL by 
>>>>>>>>>>>>>>>>>>>>> default. We have defined that NULL does not have hash 
>>>>>>>>>>>>>>>>>>>>> capability. It would be also possible to leave NULL + 
>>>>>>>>>>>>>>>>>>>>> hash to be implementation defined capability. When we say 
>>>>>>>>>>>>>>>>>>>>> that ALG_NULL is only for test, it should be enough to 
>>>>>>>>>>>>>>>>>>>>> discourage people from misusing this API for hashing.
>>>>>>>>>>>>>>>>>>>>> 2) What this means: "output should always contain data + 
>>>>>>>>>>>>>>>>>>>>> hash" ? If we enable hashing, hash is always calculated. 
>>>>>>>>>>>>>>>>>>>>> It's not optional for implementation to calculate it - 
>>>>>>>>>>>>>>>>>>>>> right.
>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>> Field name should match the type == "hash_algos" (many 
>>>>>>>>>>>>>>>>>>>>>> algorithms in a bit field). Underneath "hash_algo" is 
>>>>>>>>>>>>>>>>>>>>>> used with enum odp_comp_hash_alg_t (one algo).
>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>> I did comment the same a month back:
>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>> Is the data input only? If it is, then this should be 
>>>>>>>>>>>>>>>>>>>>>>> "const uint8_t *buf"
>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>> What is expected about the format of the data? Null 
>>>>>>>>>>>>>>>>>>>>>>> terminated strings? If it's strings, then e.g. "const 
>>>>>>>>>>>>>>>>>>>>>>> char *str" would be better.
>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>> Also the type documentation should be updated:
>>>>>>>>>>>>>>>>>>>>>>> * This is not dictionary type, but pointer into 
>>>>>>>>>>>>>>>>>>>>>>> dictionary data - right?
>>>>>>>>>>>>>>>>>>>>>>> * "Consists of pointer to byte buffer. length of 
>>>>>>>>>>>>>>>>>>>>>>> dictionary indicated by length parameter. ", this needs 
>>>>>>>>>>>>>>>>>>>>>>> clarification.  What is expected about the data behind 
>>>>>>>>>>>>>>>>>>>>>>> the pointer?
>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>> @psavol Hmm. I thought that the user should use this 
>>>>>>>>>>>>>>>>>>>>>>>> value. And `odp_comp_level_t` should be dropped from 
>>>>>>>>>>>>>>>>>>>>>>>> the spec.
>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>> How this relates to odp_comp_level_t enumeration ? 
>>>>>>>>>>>>>>>>>>>>>>>>> Shouldn't user use those levels and not a number from 
>>>>>>>>>>>>>>>>>>>>>>>>> 0 to this one ?
>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>> This is description of how de/-compression operation 
>>>>>>>>>>>>>>>>>>>>>>>>>> work. This should be specified at operation 
>>>>>>>>>>>>>>>>>>>>>>>>>> documentation, and optimally only there. Otherwise, 
>>>>>>>>>>>>>>>>>>>>>>>>>> we are in danger of this spec getting deprecated (== 
>>>>>>>>>>>>>>>>>>>>>>>>>> in conflict with operation documentation) without 
>>>>>>>>>>>>>>>>>>>>>>>>>> noticing. 
>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>> True, all types need to be odp_ prefixed. Also this 
>>>>>>>>>>>>>>>>>>>>>>>>>>> type would be better to typedef and pull out (from 
>>>>>>>>>>>>>>>>>>>>>>>>>>> inside of algo_param_t) since it's used in two 
>>>>>>>>>>>>>>>>>>>>>>>>>>> places already.
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>> As a side note: it might be logical, we might want 
>>>>>>>>>>>>>>>>>>>>>>>>>>>> to add `odp_support_t` field to notify user if 
>>>>>>>>>>>>>>>>>>>>>>>>>>>> implementation supports stateful compression. I 
>>>>>>>>>>>>>>>>>>>>>>>>>>>> can easily assume that there might be 
>>>>>>>>>>>>>>>>>>>>>>>>>>>> implementations implementing only stateless 
>>>>>>>>>>>>>>>>>>>>>>>>>>>> compression. 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_comp_alg_deflate_param, please.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Please check the see list. It mentions 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> non-existing functions.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> no result here
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> s/Else/Otherwise/
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ... an error....
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ... with valid  pkt_out and pkt_in being 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ODP_PACKET_INVALID...
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> It is an error to call this api when 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> session was created in ODP_COMP_ASYNC mode.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> As said, single and multi versions are 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> possible, but not as proposed in this 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> patch. Both versions should have the same 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> param structure and specification. Only 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> difference would be pkt_in[] vs pkt_in, 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> pkt_out[] vs pkt_out, param[] vs. param ...
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Then I propose to add a new API like
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_comp_compress_multi(const 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_packet_t pkt_in[], odp_packet_t 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> pkt_out[], const 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_comp_compress_param_t param[], int 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> num_pkt);
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> which takes of handling multiple packets 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and retain current version for single 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> packet handling.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> @bala-manoharan 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Results for both sync and async through 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> result function:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> int 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_comp_result(odp_comp_packet_result_t 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> *result, odp_packet_t packet);
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> OR have the results as output parameter. 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Results function is needed any way for 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the async operation.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shally Verma(1234sv) wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> int odp_comp_compress(const 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_packet_t pkt_in[], odp_packet_t 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> pkt_out[], const 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_comp_compress_param_t param[], int 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> num_pkt);
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Single packet version may be also 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> added, but is not necessary since 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> couple of additional if-clauses does 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> not significant overhead when compare 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> CPU cycles of the entire comp operation.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> int 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_comp_compress_single(odp_packet_t 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> pkt_in, odp_packet_t pkt_out, const 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> odp_comp_compress_param_t param);
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> The two prototypes would be the same 
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> except [] and num_pkt.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
https://github.com/Linaro/odp/pull/156#discussion_r137735561
updated_at 2017-09-08 08:27:13

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