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nghttp2/lib/nghttp2_hd.h

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/*
* nghttp2 - HTTP/2.0 C Library
*
* Copyright (c) 2013 Tatsuhiro Tsujikawa
*
* 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 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.
*/
#ifndef NGHTTP2_HD_COMP_H
#define NGHTTP2_HD_COMP_H
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <nghttp2/nghttp2.h>
#define NGHTTP2_HD_DEFAULT_MAX_BUFFER_SIZE (1 << 12)
#define NGHTTP2_HD_ENTRY_OVERHEAD 32
/* Default size of maximum table buffer size for encoder. Even if
remote decoder notifies larger buffer size for its decoding,
encoder only uses the memory up to this value. */
#define NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE (1 << 12)
typedef enum {
NGHTTP2_HD_SIDE_REQUEST = 0,
NGHTTP2_HD_SIDE_RESPONSE = 1
} nghttp2_hd_side;
typedef enum {
NGHTTP2_HD_ROLE_DEFLATE,
NGHTTP2_HD_ROLE_INFLATE
} nghttp2_hd_role;
typedef enum {
NGHTTP2_HD_FLAG_NONE = 0,
/* Indicates name was dynamically allocated and must be freed */
NGHTTP2_HD_FLAG_NAME_ALLOC = 1,
/* Indicates value was dynamically allocated and must be freed */
NGHTTP2_HD_FLAG_VALUE_ALLOC = 1 << 1,
/* Indicates that the entry is in the reference set */
NGHTTP2_HD_FLAG_REFSET = 1 << 2,
/* Indicates that the entry is emitted in the current header
processing. */
NGHTTP2_HD_FLAG_EMIT = 1 << 3,
NGHTTP2_HD_FLAG_IMPLICIT_EMIT = 1 << 4,
/* Indicates that the name was gifted to the entry and no copying
necessary. */
NGHTTP2_HD_FLAG_NAME_GIFT = 1 << 5,
/* Indicates that the value was gifted to the entry and no copying
necessary. */
NGHTTP2_HD_FLAG_VALUE_GIFT = 1 << 6
} nghttp2_hd_flags;
typedef struct {
nghttp2_nv nv;
uint32_t name_hash;
uint32_t value_hash;
/* Reference count */
uint8_t ref;
uint8_t flags;
} nghttp2_hd_entry;
typedef struct {
nghttp2_hd_entry ent;
size_t index;
} nghttp2_hd_static_entry;
typedef struct {
nghttp2_hd_entry **buffer;
size_t mask;
size_t first;
size_t len;
} nghttp2_hd_ringbuf;
typedef struct {
/* dynamic header table */
nghttp2_hd_ringbuf hd_table;
/* Pointer to the nghttp2_hd_entry which is used current header
emission. This is required because in some cases the
ent_keep->ref == 0 and we have to keep track of it. */
nghttp2_hd_entry *ent_keep;
/* Pointers to the name/value pair which are used current header
emission. They are usually used to keep track of malloc'ed memory
for huffman decoding. */
uint8_t *name_keep, *value_keep;
/* The index of header table to toggle off the entry from reference
set at the end of decompression. */
size_t end_headers_index;
/* Abstract buffer size of hd_table as described in the spec. This
is the sum of length of name/value in hd_table +
NGHTTP2_HD_ENTRY_OVERHEAD bytes overhead per each entry. */
size_t hd_table_bufsize;
/* The header table size for decoding. If the context is initialized
as encoder, this value is advertised by remote endpoint
decoder. */
size_t hd_table_bufsize_max;
/* The current effective header table size for encoding. This value
is always equal to |hd_table_bufsize| on decoder
context. |deflate_hd_table_bufsize| <= |hd_table_bufsize| must be
hold. */
size_t deflate_hd_table_bufsize;
/* The maximum effective header table for encoding. Although header
table size is bounded by |hd_table_bufsize_max|, the encoder can
use smaller buffer by not retaining the header name/values beyond
the |deflate_hd_table_bufsize_max| and not referencing those
entries. This value is always equal to |hd_table_bufsize_max| on
decoder context. */
size_t deflate_hd_table_bufsize_max;
/* The number of effective entry in |hd_table|. This value is always
equal to hd_table.len on decoder side. */
size_t deflate_hd_tablelen;
/* Role of this context; deflate or infalte */
nghttp2_hd_role role;
/* NGHTTP2_HD_SIDE_REQUEST for processing request, otherwise
response. */
nghttp2_hd_side side;
/* If inflate/deflate error occurred, this value is set to 1 and
further invocation of inflate/deflate will fail with
NGHTTP2_ERR_HEADER_COMP. */
uint8_t bad;
/* Set to this nonzero to clear reference set on each deflation each
time. */
uint8_t no_refset;
} nghttp2_hd_context;
/*
* Initializes the |ent| members. If NGHTTP2_HD_FLAG_NAME_ALLOC bit
* set in the |flags|, the content pointed by the |name| with length
* |namelen| is copied. Likewise, if NGHTTP2_HD_FLAG_VALUE_ALLOC bit
* set in the |flags|, the content pointed by the |value| with length
* |valuelen| is copied.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_entry_init(nghttp2_hd_entry *ent, uint8_t flags,
uint8_t *name, uint16_t namelen,
uint8_t *value, uint16_t valuelen);
void nghttp2_hd_entry_free(nghttp2_hd_entry *ent);
/*
* Initializes |deflater| for deflating name/values pairs.
*
* The encoder only uses up to
* NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE bytes for header table
* even if the larger value is specified later in
* nghttp2_hd_change_table_size().
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_deflate_init(nghttp2_hd_context *deflater,
nghttp2_hd_side side);
/*
* Initializes |deflater| for deflating name/values pairs.
*
* The encoder only uses up to |deflate_hd_table_bufsize_max| bytes
* for header table even if the larger value is specified later in
* nghttp2_hd_change_table_size().
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_deflate_init2(nghttp2_hd_context *deflater,
nghttp2_hd_side side,
size_t deflate_hd_table_bufsize_max);
/*
* Initializes |inflater| for inflating name/values pairs.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_inflate_init(nghttp2_hd_context *inflater,
nghttp2_hd_side side);
/*
* Deallocates any resources allocated for |deflater|.
*/
void nghttp2_hd_deflate_free(nghttp2_hd_context *deflater);
/*
* Deallocates any resources allocated for |inflater|.
*/
void nghttp2_hd_inflate_free(nghttp2_hd_context *inflater);
/*
* Sets the availability of reference set in the |deflater|. If
* |no_refset| is nonzero, the deflater will first emit index=0 in the
* each invocation of nghttp2_hd_deflate_hd() to clear up reference
* set. By default, the deflater uses reference set.
*/
void nghttp2_hd_deflate_set_no_refset(nghttp2_hd_context *deflater,
uint8_t no_refset);
/*
* Changes header table size in |context|. This may trigger eviction
* in the dynamic table.
*
* This function can be used for deflater and inflater.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_hd_change_table_size(nghttp2_hd_context *context,
size_t hd_table_bufsize_max);
/*
* Deflates the |nva|, which has the |nvlen| name/value pairs, into
* the buffer pointed by the |*buf_ptr| with the length |*buflen_ptr|.
* The output starts after |nv_offset| bytes from |*buf_ptr|.
*
* This function expands |*buf_ptr| as necessary to store the
* result. When expansion occurred, memory previously pointed by
* |*buf_ptr| may change. |*buf_ptr| and |*buflen_ptr| are updated
* accordingly.
*
* This function copies necessary data into |*buf_ptr|. After this
* function returns, it is safe to delete the |nva|.
*
* TODO: The rest of the code call nghttp2_hd_end_headers() after this
* call, but it is just a regacy of the first implementation. Now it
* is not required to be called as of now.
*
* This function returns the number of bytes outputted if it succeeds,
* or one of the following negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_HEADER_COMP
* Deflation process has failed.
*/
ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_context *deflater,
uint8_t **buf_ptr, size_t *buflen_ptr,
size_t nv_offset,
nghttp2_nv *nva, size_t nvlen);
/*
* Inflates name/value block stored in |in| with length |inlen|. This
* function performs decompression. For each successful emission of
* header name/value pair, name/value pair is assigned to the
* |nv_out| and the function returns. The caller must not free
* the members of |nv_out|.
*
* The |nv_out| includes pointers to the memory region in the
* |in|. The caller must retain the |in| while the |nv_out| is used.
*
* The application should call this function repeatedly until the
* |*final| is nonzero and return value is non-negative. This means
* the all input values are processed successfully. If |*final| is
* nonzero, no header name/value is emitted. Then the application must
* call `nghttp2_hd_inflate_end_headers()` to prepare for the next
* header block input.
*
* Currently, the whole compressed header block must be given in the
* |in| and |inlen|. Otherwise, it may lead to NGHTTP2_ERR_HEADER_COMP
* error.
*
* This function returns the number of bytes processed if it succeeds,
* or one of the following negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_HEADER_COMP
* Inflation process has failed.
*/
ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_context *inflater,
nghttp2_nv *nv_out, int *final,
uint8_t *in, size_t inlen);
/*
* Signals the end of decompression for one header block.
*
* This function returns 0 if it succeeds. Currently this function
* always succeeds.
*/
int nghttp2_hd_inflate_end_headers(nghttp2_hd_context *inflater);
/* For unittesting purpose */
int nghttp2_hd_emit_indname_block(uint8_t **buf_ptr, size_t *buflen_ptr,
size_t *offset_ptr, size_t index,
const uint8_t *value, size_t valuelen,
int inc_indexing,
nghttp2_hd_side side);
/* For unittesting purpose */
int nghttp2_hd_emit_newname_block(uint8_t **buf_ptr, size_t *buflen_ptr,
size_t *offset_ptr, nghttp2_nv *nv,
int inc_indexing,
nghttp2_hd_side side);
/* For unittesting purpose */
int nghttp2_hd_emit_subst_indname_block(uint8_t **buf_ptr, size_t *buflen_ptr,
size_t *offset_ptr, size_t index,
const uint8_t *value, size_t valuelen,
size_t subindex);
/* For unittesting purpose */
int nghttp2_hd_emit_subst_newname_block(uint8_t **buf_ptr, size_t *buflen_ptr,
size_t *offset_ptr, nghttp2_nv *nv,
size_t subindex);
/* For unittesting purpose */
nghttp2_hd_entry* nghttp2_hd_table_get(nghttp2_hd_context *context,
size_t index);
/* Huffman encoding/decoding functions */
/*
* Counts the required bytes to encode |src| with length |len|. If
* |side| is NGHTTP2_HD_SIDE_REQUEST, the request huffman code table
* is used. Otherwise, the response code table is used.
*
* This function returns the number of required bytes to encode given
* data, including padding of prefix of terminal symbol code. This
* function always succeeds.
*/
size_t nghttp2_hd_huff_encode_count(const uint8_t *src, size_t len,
nghttp2_hd_side side);
/*
* Encodes the given data |src| with length |srclen| to the given
* memory location pointed by |dest|, allocated at lest |destlen|
* bytes. The caller is responsible to specify |destlen| at least the
* length that nghttp2_hd_huff_encode_count() returns. If |side| is
* NGHTTP2_HD_SIDE_REQUEST, the request huffman code table is
* used. Otherwise, the response code table is used.
*
* This function returns the number of written bytes, including
* padding of prefix of terminal symbol code. This return value is
* exactly the same with the return value of
* nghttp2_hd_huff_encode_count() if it is given with the same |src|,
* |srclen|, and |side|. This function always succeeds.
*/
ssize_t nghttp2_hd_huff_encode(uint8_t *dest, size_t destlen,
const uint8_t *src, size_t srclen,
nghttp2_hd_side side);
/*
* Counts the number of required bytes to decode |src| with length
* |srclen|. The given input must be padded with the prefix of
* terminal code. If |side| is NGHTTP2_HD_SIDE_REQUEST, the request
* huffman code table is used. Otherwise, the response code table is
* used.
*
* This function returns the number of required bytes to decode given
* data if it succeeds, or -1.
*/
ssize_t nghttp2_hd_huff_decode_count(const uint8_t *src, size_t srclen,
nghttp2_hd_side side);
/*
* Decodes the given data |src| with length |srclen|. This function
* allocates memory to store the result and assigns the its pointer to
* |*dest_ptr| on success. The caller is responsible to release the
* memory pointed by |*dest_ptr| if this function succeeds. If |side|
* is NGHTTP2_HD_SIDE_REQUEST, the request huffman code table is
* used. Otherwise, the response code table is used.
*
* This function returns the number of written bytes. This return
* value is exactly the same with the return value of
* nghttp2_hd_huff_decode_count() if it is given with the same |src|,
* |srclen|, and |side|.
*
* If this function fails, it returns one of the following negative
* return codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_HEADER_COMP
* Decoding process has failed.
*/
ssize_t nghttp2_hd_huff_decode(uint8_t **dest_ptr,
const uint8_t *src, size_t srclen,
nghttp2_hd_side side);
#endif /* NGHTTP2_HD_COMP_H */
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