add helper functions for buffer read & write
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localvar
parent
4563289f94
commit
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/*
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* Copyright (c) 2020 TAOS Data, Inc. <jhtao@taosdata.com>
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*
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* This program is free software: you can use, redistribute, and/or modify
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* it under the terms of the GNU Affero General Public License, version 3
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* or later ("AGPL"), as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stddef.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <setjmp.h>
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#ifndef TDENGINE_TBUFFER_H
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#define TDENGINE_TBUFFER_H
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/*
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SBuffer can be used to read or write a buffer, but cannot be used for both
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read & write at a same time.
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Read example:
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SBuffer rbuf;
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if (tbufBeginOperation(&rbuf) != 0) {
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// handling errors
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}
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tbufInitRead(&rbuf, data, 1024);
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int32_t a = tbufReadInt32(&rbuf);
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// other read functions
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Write example:
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SBuffer wbuf;
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if (tbufBeginOperation(&wbuf) != 0) {
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// handling errors
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}
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tbufInitWrite(&wbuf, 1024);
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tbufWriteInt32(&wbuf, 10);
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// other write functions
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size_t size = tbufGetSize(&wbuf);
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char* data = tbufGetBuffer(&wbuf, true);
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tbufUninitWrite(&wbuf);
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*/
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typedef struct {
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jmp_buf jb;
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char* buf;
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size_t pos;
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size_t size;
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} SBuffer;
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// common functions can be used in both read & write
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#define tbufBeginOperation(buf) setjmp((buf)->jb)
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size_t tbufTell(SBuffer* buf);
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size_t tbufSeekTo(SBuffer* buf, size_t pos);
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size_t tbufSkip(SBuffer* buf, size_t size);
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// basic read functions
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void tbufInitRead(SBuffer* buf, void* data, size_t size);
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char* tbufRead(SBuffer* buf, size_t size);
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void tbufReadToBuffer(SBuffer* buf, void* dst, size_t size);
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const char* tbufReadString(SBuffer* buf, size_t* len);
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size_t tbufReadToString(SBuffer* buf, char* dst, size_t size);
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// basic write functions
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void tbufInitWrite(SBuffer* buf, size_t size);
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void tbufEnsureCapacity(SBuffer* buf, size_t size);
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char* tbufGetResult(SBuffer* buf, bool takeOver);
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void tbufUninitWrite(SBuffer* buf);
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void tbufWrite(SBuffer* buf, const void* data, size_t size);
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void tbufWriteAt(SBuffer* buf, size_t pos, const void* data, size_t size);
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void tbufWriteStringLen(SBuffer* buf, const char* str, size_t len);
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void tbufWriteString(SBuffer* buf, const char* str);
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// read & write function for primitive types
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#ifndef TBUFFER_DEFINE_OPERATION
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#define TBUFFER_DEFINE_OPERATION(type, name) \
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type tbufRead##name(SBuffer* buf); \
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void tbufWrite##name(SBuffer* buf, type data); \
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void tbufWrite##name##At(SBuffer* buf, size_t pos, type data);
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#endif
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TBUFFER_DEFINE_OPERATION( bool, Bool )
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TBUFFER_DEFINE_OPERATION( char, Char )
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TBUFFER_DEFINE_OPERATION( int8_t, Int8 )
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TBUFFER_DEFINE_OPERATION( uint8_t, Unt8 )
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TBUFFER_DEFINE_OPERATION( int16_t, Int16 )
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TBUFFER_DEFINE_OPERATION( uint16_t, Uint16 )
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TBUFFER_DEFINE_OPERATION( int32_t, Int32 )
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TBUFFER_DEFINE_OPERATION( uint32_t, Uint32 )
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TBUFFER_DEFINE_OPERATION( int64_t, Int64 )
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TBUFFER_DEFINE_OPERATION( uint64_t, Uint64 )
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TBUFFER_DEFINE_OPERATION( float, Float )
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TBUFFER_DEFINE_OPERATION( double, Double )
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#endif
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@ -0,0 +1,158 @@
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/*
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* Copyright (c) 2020 TAOS Data, Inc. <jhtao@taosdata.com>
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*
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* This program is free software: you can use, redistribute, and/or modify
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* it under the terms of the GNU Affero General Public License, version 3
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* or later ("AGPL"), as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#define TBUFFER_DEFINE_OPERATION(type, name) \
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type tbufRead##name(SBuffer* buf) { \
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type ret; \
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tbufReadToBuffer(buf, &ret, sizeof(type)); \
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return ret; \
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}\
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void tbufWrite##name(SBuffer* buf, type data) {\
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tbufWrite(buf, &data, sizeof(data));\
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}\
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void tbufWrite##name##At(SBuffer* buf, size_t pos, type data) {\
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tbufWriteAt(buf, pos, &data, sizeof(data));\
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}
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#include "../inc/tbuffer.h"
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////////////////////////////////////////////////////////////////////////////////
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// common functions
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size_t tbufTell(SBuffer* buf) {
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return buf->pos;
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}
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size_t tbufSeekTo(SBuffer* buf, size_t pos) {
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if (pos > buf->size) {
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longjmp(buf->jb, 1);
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}
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size_t old = buf->pos;
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buf->pos = pos;
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return old;
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}
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size_t tbufSkip(SBuffer* buf, size_t size) {
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return tbufSeekTo(buf, buf->pos + size);
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}
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////////////////////////////////////////////////////////////////////////////////
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// read functions
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void tbufInitRead(SBuffer* buf, void* data, size_t size) {
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buf->buf = (char*)data;
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buf->pos = 0;
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// empty buffer is not an error, but read an empty buffer is
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buf->size = (data == NULL) ? 0 : size;
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}
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char* tbufRead(SBuffer* buf, size_t size) {
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char* ret = buf->buf + buf->pos;
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tbufSkip(buf, size);
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return ret;
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}
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void tbufReadToBuffer(SBuffer* buf, void* dst, size_t size) {
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assert(dst != NULL);
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// always using memcpy, leave optimization to compiler
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memcpy(dst, tbufRead(buf, size), size);
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}
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const char* tbufReadString(SBuffer* buf, size_t* len) {
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uint16_t l = tbufReadUint16();
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char* ret = buf->buf + buf->pos;
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tbufSkip(buf, l + 1);
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ret[l] = 0; // ensure the string end with '\0'
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if (len != NULL) {
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*len = l;
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}
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return ret;
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}
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size_t tbufReadToString(SBuffer* buf, char* dst, size_t size) {
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size_t len;
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const char* str = tbufReadString(buf, &len);
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if (len >= size) len = size - 1;
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memcpy(dst, str, len);
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dst[len] = 0;
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return len;
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}
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////////////////////////////////////////////////////////////////////////////////
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// write functions
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void tbufEnsureCapacity(SBuffer* buf, size_t size) {
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size += buf->pos;
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if (size > buf->size) {
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char* nbuf = NULL;
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size_t nsize = size + buf->size;
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nbuf = realloc(buf->buf, nsize);
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if (nbuf == NULL) {
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longjmp(buf->jb, 2);
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}
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buf->buf = nbuf;
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buf->size = nsize;
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}
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}
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void tbufInitWrite(SBuffer* buf, size_t size) {
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buf->buf = NULL;
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buf->pos = 0;
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buf->size = 0;
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tbufEnsureCapacity(buf, size);
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}
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char* tbufGetResult(SBuffer* buf, bool takeOver) {
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char* ret = buf->buf;
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if (takeOver) {
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buf->pos = 0;
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buf->size = 0;
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buf->buf = NULL;
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}
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return ret;
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}
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void tbufUninitWrite(SBuffer* buf) {
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free(buf->buf);
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}
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void tbufWrite(SBuffer* buf, const void* data, size_t size) {
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tbufEnsureCapacity(size);
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memcpy(buf->buf + buf->pos, data, size);
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buf->pos += size;
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}
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void tbufWriteAt(SBuffer* buf, size_t pos, const void* data, size_t size) {
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// this function can only be called to fill the gap on previous writes,
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// so 'pos + size <= buf->pos' must be true
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if (pos + size > buf->pos) {
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longjmp(buf->jb, 3);
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}
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memcpy(buf->buf + pos, data, size);
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}
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void tbufWriteStringLen(SBuffer* buf, const char* str, size_t len) {
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if (len > 0xffff) {
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longjmp(buf->jb , 4);
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}
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tbufWriteUint16(buf, (uint16_t)len);
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tbufWrite(buf, str, len + 1);
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}
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void tbufWriteString(SBuffer* buf, const char* str) {
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tbufWriteStringLen(buf, str, strlen(str));
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}
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