| // Copyright 2017 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // https://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| // |
| // SPDX-License-Identifier: Apache-2.0 OR MIT |
| |
| // ---------------- I/O |
| // |
| // See (/doc/note/io-input-output.md). |
| |
| // wuffs_base__io_buffer_meta is the metadata for a wuffs_base__io_buffer's |
| // data. |
| typedef struct wuffs_base__io_buffer_meta__struct { |
| size_t wi; // Write index. Invariant: wi <= len. |
| size_t ri; // Read index. Invariant: ri <= wi. |
| uint64_t pos; // Buffer position (relative to the start of stream). |
| bool closed; // No further writes are expected. |
| } wuffs_base__io_buffer_meta; |
| |
| // wuffs_base__io_buffer is a 1-dimensional buffer (a pointer and length) plus |
| // additional metadata. |
| // |
| // A value with all fields zero is a valid, empty buffer. |
| typedef struct wuffs_base__io_buffer__struct { |
| wuffs_base__slice_u8 data; |
| wuffs_base__io_buffer_meta meta; |
| |
| #ifdef __cplusplus |
| inline bool is_valid() const; |
| inline void compact(); |
| inline void compact_retaining(uint64_t history_retain_length); |
| inline size_t reader_length() const; |
| inline uint8_t* reader_pointer() const; |
| inline uint64_t reader_position() const; |
| inline wuffs_base__slice_u8 reader_slice() const; |
| inline size_t writer_length() const; |
| inline uint8_t* writer_pointer() const; |
| inline uint64_t writer_position() const; |
| inline wuffs_base__slice_u8 writer_slice() const; |
| #endif // __cplusplus |
| |
| } wuffs_base__io_buffer; |
| |
| static inline wuffs_base__io_buffer // |
| wuffs_base__make_io_buffer(wuffs_base__slice_u8 data, |
| wuffs_base__io_buffer_meta meta) { |
| wuffs_base__io_buffer ret; |
| ret.data = data; |
| ret.meta = meta; |
| return ret; |
| } |
| |
| static inline wuffs_base__io_buffer_meta // |
| wuffs_base__make_io_buffer_meta(size_t wi, |
| size_t ri, |
| uint64_t pos, |
| bool closed) { |
| wuffs_base__io_buffer_meta ret; |
| ret.wi = wi; |
| ret.ri = ri; |
| ret.pos = pos; |
| ret.closed = closed; |
| return ret; |
| } |
| |
| static inline wuffs_base__io_buffer // |
| wuffs_base__ptr_u8__reader(uint8_t* ptr, size_t len, bool closed) { |
| wuffs_base__io_buffer ret; |
| ret.data.ptr = ptr; |
| ret.data.len = len; |
| ret.meta.wi = len; |
| ret.meta.ri = 0; |
| ret.meta.pos = 0; |
| ret.meta.closed = closed; |
| return ret; |
| } |
| |
| static inline wuffs_base__io_buffer // |
| wuffs_base__ptr_u8__writer(uint8_t* ptr, size_t len) { |
| wuffs_base__io_buffer ret; |
| ret.data.ptr = ptr; |
| ret.data.len = len; |
| ret.meta.wi = 0; |
| ret.meta.ri = 0; |
| ret.meta.pos = 0; |
| ret.meta.closed = false; |
| return ret; |
| } |
| |
| static inline wuffs_base__io_buffer // |
| wuffs_base__slice_u8__reader(wuffs_base__slice_u8 s, bool closed) { |
| wuffs_base__io_buffer ret; |
| ret.data.ptr = s.ptr; |
| ret.data.len = s.len; |
| ret.meta.wi = s.len; |
| ret.meta.ri = 0; |
| ret.meta.pos = 0; |
| ret.meta.closed = closed; |
| return ret; |
| } |
| |
| static inline wuffs_base__io_buffer // |
| wuffs_base__slice_u8__writer(wuffs_base__slice_u8 s) { |
| wuffs_base__io_buffer ret; |
| ret.data.ptr = s.ptr; |
| ret.data.len = s.len; |
| ret.meta.wi = 0; |
| ret.meta.ri = 0; |
| ret.meta.pos = 0; |
| ret.meta.closed = false; |
| return ret; |
| } |
| |
| static inline wuffs_base__io_buffer // |
| wuffs_base__empty_io_buffer(void) { |
| wuffs_base__io_buffer ret; |
| ret.data.ptr = NULL; |
| ret.data.len = 0; |
| ret.meta.wi = 0; |
| ret.meta.ri = 0; |
| ret.meta.pos = 0; |
| ret.meta.closed = false; |
| return ret; |
| } |
| |
| static inline wuffs_base__io_buffer_meta // |
| wuffs_base__empty_io_buffer_meta(void) { |
| wuffs_base__io_buffer_meta ret; |
| ret.wi = 0; |
| ret.ri = 0; |
| ret.pos = 0; |
| ret.closed = false; |
| return ret; |
| } |
| |
| static inline bool // |
| wuffs_base__io_buffer__is_valid(const wuffs_base__io_buffer* buf) { |
| if (buf) { |
| if (buf->data.ptr) { |
| return (buf->meta.ri <= buf->meta.wi) && (buf->meta.wi <= buf->data.len); |
| } else { |
| return (buf->meta.ri == 0) && (buf->meta.wi == 0) && (buf->data.len == 0); |
| } |
| } |
| return false; |
| } |
| |
| // wuffs_base__io_buffer__compact moves any written but unread bytes to the |
| // start of the buffer. |
| static inline void // |
| wuffs_base__io_buffer__compact(wuffs_base__io_buffer* buf) { |
| if (!buf || (buf->meta.ri == 0)) { |
| return; |
| } |
| buf->meta.pos = wuffs_base__u64__sat_add(buf->meta.pos, buf->meta.ri); |
| size_t new_wi = buf->meta.wi - buf->meta.ri; |
| if (new_wi != 0) { |
| memmove(buf->data.ptr, buf->data.ptr + buf->meta.ri, new_wi); |
| } |
| buf->meta.wi = new_wi; |
| buf->meta.ri = 0; |
| } |
| |
| // wuffs_base__io_buffer__compact_retaining moves any written but unread bytes |
| // closer to the start of the buffer. It retains H bytes of history (the most |
| // recently read bytes), where H is min(buf->meta.ri, history_retain_length). |
| // It is therefore a no-op if history_retain_length is UINT64_MAX. A |
| // postcondition is that buf->meta.ri == H. |
| // |
| // wuffs_base__io_buffer__compact_retaining(0) is equivalent to |
| // wuffs_base__io_buffer__compact(). |
| // |
| // For example, if buf started like this: |
| // |
| // +--- ri = 3 |
| // v |
| // abcdefgh?? len = 10, pos = 900 |
| // ^ |
| // +--- wi = 8 |
| // |
| // Then, depending on history_retain_length, the resultant buf would be: |
| // |
| // HRL = 0 defgh????? ri = 0 wi = 5 pos = 903 |
| // HRL = 1 cdefgh???? ri = 1 wi = 6 pos = 902 |
| // HRL = 2 bcdefgh??? ri = 2 wi = 7 pos = 901 |
| // HRL = 3 abcdefgh?? ri = 3 wi = 8 pos = 900 |
| // HRL = 4+ abcdefgh?? ri = 3 wi = 8 pos = 900 |
| static inline void // |
| wuffs_base__io_buffer__compact_retaining(wuffs_base__io_buffer* buf, |
| uint64_t history_retain_length) { |
| if (!buf || (buf->meta.ri == 0)) { |
| return; |
| } |
| size_t old_ri = buf->meta.ri; |
| size_t new_ri = (size_t)(wuffs_base__u64__min(old_ri, history_retain_length)); |
| size_t memmove_start = old_ri - new_ri; |
| buf->meta.pos = wuffs_base__u64__sat_add(buf->meta.pos, memmove_start); |
| size_t new_wi = buf->meta.wi - memmove_start; |
| if ((new_wi != 0) && (memmove_start != 0)) { |
| memmove(buf->data.ptr, buf->data.ptr + memmove_start, new_wi); |
| } |
| buf->meta.wi = new_wi; |
| buf->meta.ri = new_ri; |
| } |
| |
| static inline size_t // |
| wuffs_base__io_buffer__reader_length(const wuffs_base__io_buffer* buf) { |
| return buf ? buf->meta.wi - buf->meta.ri : 0; |
| } |
| |
| static inline uint8_t* // |
| wuffs_base__io_buffer__reader_pointer(const wuffs_base__io_buffer* buf) { |
| return (buf && buf->data.ptr) ? (buf->data.ptr + buf->meta.ri) : NULL; |
| } |
| |
| static inline uint64_t // |
| wuffs_base__io_buffer__reader_position(const wuffs_base__io_buffer* buf) { |
| return buf ? wuffs_base__u64__sat_add(buf->meta.pos, buf->meta.ri) : 0; |
| } |
| |
| static inline wuffs_base__slice_u8 // |
| wuffs_base__io_buffer__reader_slice(const wuffs_base__io_buffer* buf) { |
| return (buf && buf->data.ptr) |
| ? wuffs_base__make_slice_u8(buf->data.ptr + buf->meta.ri, |
| buf->meta.wi - buf->meta.ri) |
| : wuffs_base__empty_slice_u8(); |
| } |
| |
| static inline size_t // |
| wuffs_base__io_buffer__writer_length(const wuffs_base__io_buffer* buf) { |
| return buf ? buf->data.len - buf->meta.wi : 0; |
| } |
| |
| static inline uint8_t* // |
| wuffs_base__io_buffer__writer_pointer(const wuffs_base__io_buffer* buf) { |
| return (buf && buf->data.ptr) ? (buf->data.ptr + buf->meta.wi) : NULL; |
| } |
| |
| static inline uint64_t // |
| wuffs_base__io_buffer__writer_position(const wuffs_base__io_buffer* buf) { |
| return buf ? wuffs_base__u64__sat_add(buf->meta.pos, buf->meta.wi) : 0; |
| } |
| |
| static inline wuffs_base__slice_u8 // |
| wuffs_base__io_buffer__writer_slice(const wuffs_base__io_buffer* buf) { |
| return (buf && buf->data.ptr) |
| ? wuffs_base__make_slice_u8(buf->data.ptr + buf->meta.wi, |
| buf->data.len - buf->meta.wi) |
| : wuffs_base__empty_slice_u8(); |
| } |
| |
| #ifdef __cplusplus |
| |
| inline bool // |
| wuffs_base__io_buffer::is_valid() const { |
| return wuffs_base__io_buffer__is_valid(this); |
| } |
| |
| inline void // |
| wuffs_base__io_buffer::compact() { |
| wuffs_base__io_buffer__compact(this); |
| } |
| |
| inline void // |
| wuffs_base__io_buffer::compact_retaining(uint64_t history_retain_length) { |
| wuffs_base__io_buffer__compact_retaining(this, history_retain_length); |
| } |
| |
| inline size_t // |
| wuffs_base__io_buffer::reader_length() const { |
| return wuffs_base__io_buffer__reader_length(this); |
| } |
| |
| inline uint8_t* // |
| wuffs_base__io_buffer::reader_pointer() const { |
| return wuffs_base__io_buffer__reader_pointer(this); |
| } |
| |
| inline uint64_t // |
| wuffs_base__io_buffer::reader_position() const { |
| return wuffs_base__io_buffer__reader_position(this); |
| } |
| |
| inline wuffs_base__slice_u8 // |
| wuffs_base__io_buffer::reader_slice() const { |
| return wuffs_base__io_buffer__reader_slice(this); |
| } |
| |
| inline size_t // |
| wuffs_base__io_buffer::writer_length() const { |
| return wuffs_base__io_buffer__writer_length(this); |
| } |
| |
| inline uint8_t* // |
| wuffs_base__io_buffer::writer_pointer() const { |
| return wuffs_base__io_buffer__writer_pointer(this); |
| } |
| |
| inline uint64_t // |
| wuffs_base__io_buffer::writer_position() const { |
| return wuffs_base__io_buffer__writer_position(this); |
| } |
| |
| inline wuffs_base__slice_u8 // |
| wuffs_base__io_buffer::writer_slice() const { |
| return wuffs_base__io_buffer__writer_slice(this); |
| } |
| |
| #endif // __cplusplus |