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#ifndef SRL_BUFFER_H_
#define SRL_BUFFER_H_
#include "assert.h"
#include "srl_inline.h"
#include "srl_common.h"
#include "srl_buffer_types.h"
#ifdef MEMDEBUG
# define BUFFER_GROWTH_FACTOR 1
#else
# define BUFFER_GROWTH_FACTOR 2
#endif
/* The static's below plus the ifndef sort of make this header only
* usable in one place per compilation unit. Drop "static" when necessary.
* For now, potentially smaller code wins. */
/* buffer operations */
#define BUF_POS_OFS(buf) (((buf)->pos) - ((buf)->start))
#define BUF_SPACE(buf) (((buf)->end) - ((buf)->pos))
#define BUF_SIZE(buf) (((buf)->end) - ((buf)->start))
#define BUF_NEED_GROW(buf, minlen) ((size_t)BUF_SPACE(buf) <= minlen)
#define BUF_NEED_GROW_TOTAL(buf, minlen) ((size_t)BUF_SIZE(buf) <= minlen)
#define BUF_NOT_DONE(buf) ((buf)->pos < (buf)->end)
#define BUF_DONE(buf) ((buf)->pos >= (buf)->end)
/* body-position/size related operations */
#define BODY_POS_OFS(buf) (((buf)->pos) - ((buf)->body_pos))
/* these are mostly for right between (de)serializing the header and the body */
#define SRL_SET_BODY_POS(buf, pos_ptr) ((buf)->body_pos = pos_ptr)
#define SRL_UPDATE_BODY_POS(buf, protocol_version) \
STMT_START { \
if (expect_false((protocol_version) == 1)) { \
SRL_SET_BODY_POS((buf), (buf)->start); \
} else { \
SRL_SET_BODY_POS((buf), (buf)->pos-1); \
} \
} STMT_END
/* Internal debugging macros, used only in DEBUG mode */
#ifndef NDEBUG
#define DEBUG_ASSERT_BUF_SPACE(buf, len) STMT_START { \
if((BUF_SPACE(buf) < (ptrdiff_t)(len))) { \
warn("failed assertion check - pos: %ld [%p %p %p] %ld < %ld", \
(long)BUF_POS_OFS(buf), (buf)->start, \
(buf)->pos, (buf)->end, \
(long)BUF_SPACE(buf),(long)(len)); \
} \
assert(BUF_SPACE(buf) >= (ptrdiff_t)(len)); \
} STMT_END
#else
#define DEBUG_ASSERT_BUF_SPACE(buf, len) ((void)0)
#endif
#ifndef NDEBUG
#define DEBUG_ASSERT_BUF_SANE(buf) STMT_START { \
if(!(((buf)->start <= (buf)->pos) && ((buf)->pos <= (buf)->end))){ \
warn("failed sanity assertion check - pos: %ld [%p %p %p] %ld", \
(long)BUF_POS_OFS(buf), (buf)->start, \
(buf)->pos, (buf)->end, (long)BUF_SPACE(buf)); \
} \
assert(((buf)->start <= (buf)->pos) && ((buf)->pos <= (buf)->end)); \
} STMT_END
#else
#define DEBUG_ASSERT_BUF_SANE(buf) \
assert(((buf)->start <= (buf)->pos) && ((buf)->pos <= (buf)->end))
#endif
/* Allocate a virgin buffer (but not the buffer struct) */
SRL_STATIC_INLINE int
srl_buf_init_buffer(pTHX_ srl_buffer_t *buf, const STRLEN init_size)
{
Newx(buf->start, init_size, srl_buffer_char);
if (expect_false( buf->start == NULL ))
return 1;
buf->end = buf->start + init_size - 1;
buf->pos = buf->start;
buf->body_pos = buf->start; /* SRL_SET_BODY_POS(enc, enc->buf.start) equiv */
return 0;
}
/* Free a buffer (but not the buffer struct) */
SRL_STATIC_INLINE void
srl_buf_free_buffer(pTHX_ srl_buffer_t *buf)
{
Safefree(buf->start);
}
/* Copy one buffer to another (shallowly!) */
SRL_STATIC_INLINE void
srl_buf_copy_buffer(pTHX_ srl_buffer_t *src, srl_buffer_t *dest)
{
Copy(src, dest, 1, srl_buffer_t);
}
/* Swap two buffers */
SRL_STATIC_INLINE void
srl_buf_swap_buffer(pTHX_ srl_buffer_t *buf1, srl_buffer_t *buf2)
{
srl_buffer_t tmp;
Copy(buf1, &tmp, 1, srl_buffer_t);
Copy(buf2, buf1, 1, srl_buffer_t);
Copy(&tmp, buf2, 1, srl_buffer_t);
}
SRL_STATIC_INLINE void
srl_buf_grow_nocheck(pTHX_ srl_buffer_t *buf, size_t minlen)
{
const size_t pos_ofs= BUF_POS_OFS(buf); /* have to store the offset of pos */
const size_t body_ofs= buf->body_pos - buf->start; /* have to store the offset of the body */
#ifdef MEMDEBUG
const size_t new_size = minlen;
#else
const size_t cur_size = BUF_SIZE(buf);
const size_t grown_len = (size_t)(cur_size * BUFFER_GROWTH_FACTOR);
const size_t new_size = 100 + (minlen > grown_len ? minlen : grown_len);
#endif
DEBUG_ASSERT_BUF_SANE(buf);
/* assert that Renew means GROWING the buffer */
assert(buf->start + new_size > buf->end);
Renew(buf->start, new_size, srl_buffer_char);
if (buf->start == NULL)
croak("Out of memory!");
buf->end = (srl_buffer_char*) (buf->start + new_size);
buf->pos = buf->start + pos_ofs;
SRL_SET_BODY_POS(buf, buf->start + body_ofs);
DEBUG_ASSERT_BUF_SANE(buf);
assert(buf->end - buf->start > (ptrdiff_t)0);
assert(buf->pos - buf->start >= (ptrdiff_t)0);
/* The following is checking against -1 because SRL_UPDATE_BODY_POS
* will actually set the body_pos to pos-1, where pos can be 0.
* This works out fine in the end, but is admittedly a bit shady.
* FIXME */
assert(buf->body_pos - buf->start >= (ptrdiff_t)-1);
}
#define BUF_SIZE_ASSERT(buf, minlen) \
STMT_START { \
DEBUG_ASSERT_BUF_SANE(buf); \
if (BUF_NEED_GROW(buf, minlen)) \
srl_buf_grow_nocheck(aTHX_ (buf), (BUF_SIZE(buf) + minlen)); \
DEBUG_ASSERT_BUF_SANE(buf); \
} STMT_END
#define BUF_SIZE_ASSERT_TOTAL(buf, minlen) \
STMT_START { \
DEBUG_ASSERT_BUF_SANE(buf); \
if (BUF_NEED_GROW_TOTAL(buf, minlen)) \
srl_buf_grow_nocheck(aTHX_ (buf), (minlen)); \
DEBUG_ASSERT_BUF_SANE(buf); \
} STMT_END
SRL_STATIC_INLINE void
srl_buf_cat_str_int(pTHX_ srl_buffer_t *buf, const char *str, size_t len)
{
BUF_SIZE_ASSERT(buf, len);
Copy(str, buf->pos, len, char);
buf->pos += len;
DEBUG_ASSERT_BUF_SANE(buf);
}
#define srl_buf_cat_str(buf, str, len) srl_buf_cat_str_int(aTHX_ buf, str, len)
/* see perl.git:handy.h STR_WITH_LEN macro for explanation of the below code */
#define srl_buf_cat_str_s(buf, str) srl_buf_cat_str(buf, ("" str ""), sizeof(str)-1)
SRL_STATIC_INLINE void
srl_buf_cat_str_nocheck_int(pTHX_ srl_buffer_t *buf, const char *str, size_t len)
{
DEBUG_ASSERT_BUF_SANE(buf);
DEBUG_ASSERT_BUF_SPACE(buf, len);
Copy(str, buf->pos, len, char);
buf->pos += len;
DEBUG_ASSERT_BUF_SANE(buf);
}
#define srl_buf_cat_str_nocheck(buf, str, len) srl_buf_cat_str_nocheck_int(aTHX_ buf, str, len)
/* see perl.git:handy.h STR_WITH_LEN macro for explanation of the below code */
#define srl_buf_cat_str_s_nocheck(buf, str) srl_buf_cat_str_nocheck(buf, ("" str ""), sizeof(str)-1)
SRL_STATIC_INLINE void
srl_buf_cat_char_int(pTHX_ srl_buffer_t *buf, const char c)
{
DEBUG_ASSERT_BUF_SANE(buf);
BUF_SIZE_ASSERT(buf, 1);
DEBUG_ASSERT_BUF_SPACE(buf, 1);
*buf->pos++ = c;
DEBUG_ASSERT_BUF_SANE(buf);
}
#define srl_buf_cat_char(buf, c) srl_buf_cat_char_int(aTHX_ buf, c)
SRL_STATIC_INLINE void
srl_buf_cat_char_nocheck_int(pTHX_ srl_buffer_t *buf, const char c)
{
DEBUG_ASSERT_BUF_SANE(buf);
DEBUG_ASSERT_BUF_SPACE(buf, 1);
*buf->pos++ = c;
DEBUG_ASSERT_BUF_SANE(buf);
}
#define srl_buf_cat_char_nocheck(buf, c) srl_buf_cat_char_nocheck_int(aTHX_ buf, c)
/* define constant for other code to use in preallocations */
#define SRL_MAX_VARINT_LENGTH 11
/*
* This implements "varint" and "zigzag varint" types as used in protobufs, etc.
*
* varint is a variable length encoding of unsigned integers, where the low
* 7 bits of the input value are encoded into each byte of output, with the high bit
* used as a flag to indicate there is another byte worth of bits to be read.
*
* zigzag is a way of encoding signed integers as an unsigned integer in such a way
* that positive and negative numbers are interleaved, so that z0=0, z1=-1, z2=1,
* z3=-2, z4=2, etc. When the zigzag form is represented as a varint, the result is
* that both negative and positive number take space proportional to their distance
* from zero.
*
* see: https://developers.google.com/protocol-buffers/docs/encoding#types
*
*/
#define srl_varint_size(x) ( \
z <= (1UL << 7) ? 1 : \
z <= (1UL << 14) ? 2 : \
z <= (1UL << 21) ? 3 : \
z <= (1UL << 28) ? 4 : \
z <= (1UL << 35) ? 5 : \
z <= (1UL << 42) ? 6 : \
z <= (1UL << 49) ? 7 : \
z <= (1UL << 56) ? 8 : \
z <= (1UL << 63) ? 9 : \
10 )
SRL_STATIC_INLINE void
srl_buf_cat_varint_raw_nocheck(pTHX_ srl_buffer_t *buf, UV value) {
DEBUG_ASSERT_BUF_SANE(buf);
DEBUG_ASSERT_BUF_SPACE(buf, SRL_MAX_VARINT_LENGTH);
while (value >= 0x80) { /* while we are larger than 7 bits long */
*buf->pos++ = (value & 0x7f) | 0x80; /* write out the least significant 7 bits, set the high bit */
value >>= 7; /* shift off the 7 least significant bits */
}
*buf->pos++ = (U8)value; /* encode the last 7 bits without the high bit being set */
DEBUG_ASSERT_BUF_SANE(buf);
}
SRL_STATIC_INLINE UV
srl_zigzag_iv(IV value) {
return (UV)((value << 1) ^ (value >> (sizeof(IV) * 8 - 1)));
}
SRL_STATIC_INLINE void
srl_buf_cat_zigzag_raw_nocheck(pTHX_ srl_buffer_t *buf, const IV value) {
srl_buf_cat_varint_raw_nocheck(aTHX_ buf, srl_zigzag_iv(value));
}
SRL_STATIC_INLINE void
srl_buf_cat_varint_nocheck(pTHX_ srl_buffer_t *buf, const char tag, UV value) {
DEBUG_ASSERT_BUF_SPACE(buf, 1);
if (expect_true( tag ))
*buf->pos++ = tag;
srl_buf_cat_varint_raw_nocheck(aTHX_ buf, value);
}
SRL_STATIC_INLINE void
srl_buf_cat_zigzag_nocheck(pTHX_ srl_buffer_t *buf, const char tag, const IV value) {
srl_buf_cat_varint_nocheck(aTHX_ buf, tag, srl_zigzag_iv(value));
}
SRL_STATIC_INLINE void
srl_buf_cat_varint(pTHX_ srl_buffer_t *buf, const char tag, const UV value) {
/* this implements "varint" from google protocol buffers */
BUF_SIZE_ASSERT(buf, SRL_MAX_VARINT_LENGTH + 1); /* always allocate space for the tag, overalloc is harmless */
srl_buf_cat_varint_nocheck(aTHX_ buf, tag, value);
}
SRL_STATIC_INLINE void
srl_buf_cat_zigzag(pTHX_ srl_buffer_t *buf, const char tag, const IV value) {
srl_buf_cat_varint(aTHX_ buf, tag, srl_zigzag_iv(value));
}
#endif
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