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| -rw-r--r-- | ext/atom.lv2/atom-buffer.h | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/ext/atom.lv2/atom-buffer.h b/ext/atom.lv2/atom-buffer.h new file mode 100644 index 0000000..2ac71e3 --- /dev/null +++ b/ext/atom.lv2/atom-buffer.h @@ -0,0 +1,170 @@ +/* + Copyright 2008-2011 David Robillard <http://drobilla.net> + + Permission to use, copy, modify, and/or distribute this software for any + purpose with or without fee is hereby granted, provided that the above + copyright notice and this permission notice appear in all copies. + + THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + +/** + @file atom-event-buffer.h Helper functions for atom:EventBuffer. + + Note that these functions are all static inline which basically means: + do not take the address of these functions. +*/ + +#ifndef LV2_ATOM_EVENT_BUFFER_H +#define LV2_ATOM_EVENT_BUFFER_H + +#include <stdint.h> +#include <stdbool.h> +#include <string.h> +#include <stdlib.h> +#include <assert.h> + +#include "lv2/lv2plug.in/ns/ext/atom/atom.h" + +/** + Pad a size to 64 bits. +*/ +static inline uint32_t +lv2_atom_pad_size(uint32_t size) +{ + return (size + 7) & (~7); +} + +/** + Initialize an existing atom buffer. + All fields of @c buf are reset, except capacity which is unmodified. +*/ +static inline void +lv2_atom_buffer_reset(LV2_Atom_Buffer* buf) +{ + buf->event_count = 0; + buf->size = 0; +} + +/** + Allocate a new, empty atom buffer. +*/ +static inline LV2_Atom_Buffer* +lv2_atom_buffer_new(uint32_t capacity) +{ + const uint32_t size = sizeof(LV2_Atom_Buffer) + capacity; + LV2_Atom_Buffer* buf = (LV2_Atom_Buffer*)malloc(size); + if (buf) { + buf->data = (uint8_t*)(buf + 1); + buf->capacity = capacity; + lv2_atom_buffer_reset(buf); + } + return buf; +} + +/** + Free an atom buffer allocated with lv2_atom_buffer_new(). +*/ +static inline void +lv2_atom_buffer_free(LV2_Atom_Buffer* buf) +{ + free(buf); +} + +/** + An iterator over an LV2_Atom_Buffer. +*/ +typedef struct { + LV2_Atom_Buffer* buf; + uint32_t offset; +} LV2_Atom_Buffer_Iterator; + +/** + Return an iterator to the beginning of @c buf. +*/ +static inline LV2_Atom_Buffer_Iterator +lv2_atom_buffer_begin(LV2_Atom_Buffer* buf) +{ + const LV2_Atom_Buffer_Iterator i = { buf, 0 }; + return i; +} + +/** + Return true iff @c i points to a valid atom. +*/ +static inline bool +lv2_atom_buffer_is_valid(LV2_Atom_Buffer_Iterator i) +{ + return i.offset < i.buf->size; +} + +/** + Return the iterator to the next element after @c i. + @param i A valid iterator to an atom in a buffer. +*/ +static inline LV2_Atom_Buffer_Iterator +lv2_atom_buffer_next(LV2_Atom_Buffer_Iterator i) +{ + assert(lv2_atom_buffer_is_valid(i)); + const LV2_Atom_Event* const ev = (LV2_Atom_Event*)( + i.buf->data + i.offset); + i.offset += lv2_atom_pad_size(sizeof(LV2_Atom_Event) + ev->body.size); + return i; +} + +/** + Return a pointer to the atom currently pointed to by @c i. +*/ +static inline LV2_Atom_Event* +lv2_atom_buffer_get(LV2_Atom_Buffer_Iterator i) +{ + assert(lv2_event_is_valid(i)); + return (LV2_Atom_Event*)(i.buf->data + i.offset); +} + +/** + Write an atom to a buffer. + + The atom will be written at the location pointed to by @c i, which will be + incremented to point to the location where the next atom should be written + (which is likely now garbage). Thus, this function can be called repeatedly + with a single @c i to write a sequence of atoms to the buffer. + + @return True if atom was written, otherwise false (buffer is full). +*/ +static inline bool +lv2_atom_buffer_write(LV2_Atom_Buffer_Iterator* i, + uint32_t frames, + uint32_t subframes, + uint32_t type, + uint32_t size, + const uint8_t* data) +{ + const uint32_t free_space = i->buf->capacity - i->buf->size; + if (free_space < sizeof(LV2_Atom_Event) + size) { + return false; + } + + LV2_Atom_Event* const ev = (LV2_Atom_Event*)(i->buf->data + i->offset); + + ev->frames = frames; + ev->subframes = subframes; + ev->body.type = type; + ev->body.size = size; + memcpy((uint8_t*)ev + sizeof(LV2_Atom_Event), data, size); + ++i->buf->event_count; + + size = lv2_atom_pad_size(sizeof(LV2_Atom_Event) + size); + i->buf->size += size; + i->offset += size; + + return true; +} + +#endif /* LV2_ATOM_EVENT_BUFFER_H */ |