// After editing this file, run "go generate" in the parent directory.

// Copyright 2020 The Wuffs Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// ---------------- Tokens

typedef struct {
  // The repr's 64 bits are divided as:
  //
  // +-----+-------------+-------+-------------+-----+-----+-----------+
  // |  1  |      21     |   3   |      21     |  1  |  1  |     16    |
  // +-----+-------------+-------+-------------+-----+-----+-----------+
  // [..................value..................]  LP    LN     length
  // [..0..|.value_major.|.....value_minor.....]
  // [..0..|.........VBC.........|.....VBD.....]
  //
  // The broad divisions are:
  //  - Bits 63 .. 18 (46 bits) is the value.
  //  - Bits 17 .. 16 ( 2 bits) is LP and LN (link_prev and link_next).
  //  - Bits 15 ..  0 (16 bits) is the length.
  //
  // The value bits can be sub-divided in multiple ways:
  //  - Bits 63 .. 63 ( 1 bits) is reserved (a zero bit).
  //  - Bits 62 .. 42 (21 bits) is the value_major.
  //  - Bits 41 .. 18 (24 bits) is the value_minor.
  //  - Bits 62 .. 39 (24 bits) is the VBC (value_base_category).
  //  - Bits 38 .. 18 (21 bits) is the VBD (value_base_detail).
  //
  // The value_major is a 21-bit [Base38](doc/note/base38-and-fourcc.md) value.
  // If all of its bits are zero (special cased for Wuffs' built-in "base"
  // package) then the value_minor is further sub-divided:
  //  - Bits 41 .. 39 ( 3 bits) is the VBC (value_base_category).
  //  - Bits 38 .. 18 (21 bits) is the VBD (value_base_detail).
  //
  // The high 46 bits (bits 63 .. 18) only have VBC and VBD semantics when the
  // high 22 bits (the value_major) are all zero. An equivalent test is that
  // the high 25 bits (the notional VBC) has a numerical value less than 8.
  //
  // At 21 bits, the VBD can hold every valid Unicode code point.
  //
  // If value_major is non-zero then value_minor has whatever arbitrary meaning
  // the tokenizer's package assigns to it.
  //
  // Multiple consecutive tokens can form a larger conceptual unit. For
  // example, an "abc\tz" string is a single higher level concept but at the
  // lower level, it could consist of multiple tokens: the quotes '"', the
  // ASCII texts "abc" and "z" and the backslash-escaped tab '\t'. The LP and
  // LN (link_prev and link_next) bits denote tokens that are part of a
  // multi-token chain:
  //  - LP means that this token is not the first (there is a previous token).
  //  - LN means that this token is not the last  (there is a next     token).
  //
  // In particular, a stand-alone token will have both link bits set to zero.
  uint64_t repr;

#ifdef __cplusplus
  inline uint64_t value() const;
  inline uint64_t value_major() const;
  inline uint64_t value_minor() const;
  inline uint64_t value_base_category() const;
  inline uint64_t value_base_detail() const;
  inline bool link_prev() const;
  inline bool link_next() const;
  inline uint64_t length() const;
#endif  // __cplusplus

} wuffs_base__token;

static inline wuffs_base__token  //
wuffs_base__make_token(uint64_t repr) {
  wuffs_base__token ret;
  ret.repr = repr;
  return ret;
}

  // --------

#define WUFFS_BASE__TOKEN__LENGTH__MAX_INCL 0xFFFF

#define WUFFS_BASE__TOKEN__VALUE__MASK 0x3FFFFFFFFFFF
#define WUFFS_BASE__TOKEN__VALUE_MAJOR__MASK 0x3FFFFF
#define WUFFS_BASE__TOKEN__VALUE_MINOR__MASK 0xFFFFFF
#define WUFFS_BASE__TOKEN__VALUE_BASE_CATEGORY__MASK 0x1FFFFFF
#define WUFFS_BASE__TOKEN__VALUE_BASE_DETAIL__MASK 0x1FFFFF
#define WUFFS_BASE__TOKEN__LINK__MASK 0x3
#define WUFFS_BASE__TOKEN__LENGTH__MASK 0xFFFF

#define WUFFS_BASE__TOKEN__VALUE__SHIFT 18
#define WUFFS_BASE__TOKEN__VALUE_MAJOR__SHIFT 42
#define WUFFS_BASE__TOKEN__VALUE_MINOR__SHIFT 18
#define WUFFS_BASE__TOKEN__VALUE_BASE_CATEGORY__SHIFT 39
#define WUFFS_BASE__TOKEN__VALUE_BASE_DETAIL__SHIFT 18
#define WUFFS_BASE__TOKEN__LINK__SHIFT 16
#define WUFFS_BASE__TOKEN__LENGTH__SHIFT 0

#define WUFFS_BASE__TOKEN__LINK_PREV 0x20000
#define WUFFS_BASE__TOKEN__LINK_NEXT 0x10000

  // --------

#define WUFFS_BASE__TOKEN__VBC__FILLER 0
#define WUFFS_BASE__TOKEN__VBC__STRUCTURE 1
#define WUFFS_BASE__TOKEN__VBC__STRING 2
#define WUFFS_BASE__TOKEN__VBC__UNICODE_CODE_POINT 3
#define WUFFS_BASE__TOKEN__VBC__LITERAL 4
#define WUFFS_BASE__TOKEN__VBC__NUMBER 5

  // --------

#define WUFFS_BASE__TOKEN__VBD__FILLER__COMMENT_LINE 0x00001
#define WUFFS_BASE__TOKEN__VBD__FILLER__COMMENT_BLOCK 0x00002

  // --------

#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__PUSH 0x00001
#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__POP 0x00002
#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_NONE 0x00010
#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_LIST 0x00020
#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_DICT 0x00040
#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_NONE 0x01000
#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_LIST 0x02000
#define WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_DICT 0x04000

// --------

// "DEFINITELY_FOO" means that the destination bytes (and also the source
// bytes, for 1_DST_1_SRC_COPY) are in the FOO format. Definitely means that
// the lack of the bit is conservative: it is valid for all-ASCII strings to
// have neither DEFINITELY_UTF_8 or DEFINITELY_ASCII bits set.
#define WUFFS_BASE__TOKEN__VBD__STRING__DEFINITELY_UTF_8 0x00001
#define WUFFS_BASE__TOKEN__VBD__STRING__DEFINITELY_ASCII 0x00002

// "CONVERT_D_DST_S_SRC" means that multiples of S source bytes (possibly
// padded) produces multiples of D destination bytes. For example,
// CONVERT_1_DST_4_SRC_BACKSLASH_X means a source like "\\x23\\x67\\xAB", where
// 12 src bytes encode 3 dst bytes.
//
// When src is the empty string, multiple conversion algorithms are applicable
// (so these bits are not necessarily mutually exclusive), all producing the
// same empty dst string.
#define WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_0_DST_1_SRC_DROP 0x00010
#define WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_1_SRC_COPY 0x00020
#define WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_2_SRC_HEXADECIMAL 0x00040
#define WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_4_SRC_BACKSLASH_X 0x00080
#define WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_3_DST_4_SRC_BASE_64_STD 0x00100
#define WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_3_DST_4_SRC_BASE_64_URL 0x00200
#define WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_4_DST_5_SRC_ASCII_85 0x00400

  // --------

#define WUFFS_BASE__TOKEN__VBD__LITERAL__UNDEFINED 0x00001
#define WUFFS_BASE__TOKEN__VBD__LITERAL__NULL 0x00002
#define WUFFS_BASE__TOKEN__VBD__LITERAL__FALSE 0x00004
#define WUFFS_BASE__TOKEN__VBD__LITERAL__TRUE 0x00008

  // --------

// For a source string of "123" or "0x9A", it is valid for a tokenizer to
// return any one of:
//  - WUFFS_BASE__TOKEN__VBD__NUMBER__FLOATING_POINT.
//  - WUFFS_BASE__TOKEN__VBD__NUMBER__INTEGER_SIGNED.
//  - WUFFS_BASE__TOKEN__VBD__NUMBER__INTEGER_UNSIGNED.
//
// For a source string of "+123" or "-0x9A", only the first two are valid.
//
// For a source string of "123.", only the first one is valid.
#define WUFFS_BASE__TOKEN__VBD__NUMBER__FLOATING_POINT 0x00001
#define WUFFS_BASE__TOKEN__VBD__NUMBER__INTEGER_SIGNED 0x00002
#define WUFFS_BASE__TOKEN__VBD__NUMBER__INTEGER_UNSIGNED 0x00004

// --------

static inline uint64_t  //
wuffs_base__token__value(const wuffs_base__token* t) {
  return (t->repr >> WUFFS_BASE__TOKEN__VALUE__SHIFT) &
         WUFFS_BASE__TOKEN__VALUE__MASK;
}

static inline uint64_t  //
wuffs_base__token__value_major(const wuffs_base__token* t) {
  return (t->repr >> WUFFS_BASE__TOKEN__VALUE_MAJOR__SHIFT) &
         WUFFS_BASE__TOKEN__VALUE_MAJOR__MASK;
}

static inline uint64_t  //
wuffs_base__token__value_minor(const wuffs_base__token* t) {
  return (t->repr >> WUFFS_BASE__TOKEN__VALUE_MINOR__SHIFT) &
         WUFFS_BASE__TOKEN__VALUE_MINOR__MASK;
}

static inline uint64_t  //
wuffs_base__token__value_base_category(const wuffs_base__token* t) {
  return (t->repr >> WUFFS_BASE__TOKEN__VALUE_BASE_CATEGORY__SHIFT) &
         WUFFS_BASE__TOKEN__VALUE_BASE_CATEGORY__MASK;
}

static inline uint64_t  //
wuffs_base__token__value_base_detail(const wuffs_base__token* t) {
  return (t->repr >> WUFFS_BASE__TOKEN__VALUE_BASE_DETAIL__SHIFT) &
         WUFFS_BASE__TOKEN__VALUE_BASE_DETAIL__MASK;
}

static inline bool  //
wuffs_base__token__link_prev(const wuffs_base__token* t) {
  return t->repr & WUFFS_BASE__TOKEN__LINK_PREV;
}

static inline bool  //
wuffs_base__token__link_next(const wuffs_base__token* t) {
  return t->repr & WUFFS_BASE__TOKEN__LINK_NEXT;
}

static inline uint64_t  //
wuffs_base__token__length(const wuffs_base__token* t) {
  return (t->repr >> WUFFS_BASE__TOKEN__LENGTH__SHIFT) &
         WUFFS_BASE__TOKEN__LENGTH__MASK;
}

#ifdef __cplusplus

inline uint64_t  //
wuffs_base__token::value() const {
  return wuffs_base__token__value(this);
}

inline uint64_t  //
wuffs_base__token::value_major() const {
  return wuffs_base__token__value_major(this);
}

inline uint64_t  //
wuffs_base__token::value_minor() const {
  return wuffs_base__token__value_minor(this);
}

inline uint64_t  //
wuffs_base__token::value_base_category() const {
  return wuffs_base__token__value_base_category(this);
}

inline uint64_t  //
wuffs_base__token::value_base_detail() const {
  return wuffs_base__token__value_base_detail(this);
}

inline bool  //
wuffs_base__token::link_prev() const {
  return wuffs_base__token__link_prev(this);
}

inline bool  //
wuffs_base__token::link_next() const {
  return wuffs_base__token__link_next(this);
}

inline uint64_t  //
wuffs_base__token::length() const {
  return wuffs_base__token__length(this);
}

#endif  // __cplusplus

// --------

typedef WUFFS_BASE__SLICE(wuffs_base__token) wuffs_base__slice_token;

static inline wuffs_base__slice_token  //
wuffs_base__make_slice_token(wuffs_base__token* ptr, size_t len) {
  wuffs_base__slice_token ret;
  ret.ptr = ptr;
  ret.len = len;
  return ret;
}

// --------

// wuffs_base__token_buffer_meta is the metadata for a
// wuffs_base__token_buffer's data.
typedef struct {
  size_t wi;     // Write index. Invariant: wi <= len.
  size_t ri;     // Read  index. Invariant: ri <= wi.
  uint64_t pos;  // Position of the buffer start relative to the stream start.
  bool closed;   // No further writes are expected.
} wuffs_base__token_buffer_meta;

// wuffs_base__token_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__slice_token data;
  wuffs_base__token_buffer_meta meta;

#ifdef __cplusplus
  inline void compact();
  inline uint64_t reader_available() const;
  inline uint64_t reader_token_position() const;
  inline uint64_t writer_available() const;
  inline uint64_t writer_token_position() const;
#endif  // __cplusplus

} wuffs_base__token_buffer;

static inline wuffs_base__token_buffer  //
wuffs_base__make_token_buffer(wuffs_base__slice_token data,
                              wuffs_base__token_buffer_meta meta) {
  wuffs_base__token_buffer ret;
  ret.data = data;
  ret.meta = meta;
  return ret;
}

static inline wuffs_base__token_buffer_meta  //
wuffs_base__make_token_buffer_meta(size_t wi,
                                   size_t ri,
                                   uint64_t pos,
                                   bool closed) {
  wuffs_base__token_buffer_meta ret;
  ret.wi = wi;
  ret.ri = ri;
  ret.pos = pos;
  ret.closed = closed;
  return ret;
}

static inline wuffs_base__token_buffer  //
wuffs_base__empty_token_buffer() {
  wuffs_base__token_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__token_buffer_meta  //
wuffs_base__empty_token_buffer_meta() {
  wuffs_base__token_buffer_meta ret;
  ret.wi = 0;
  ret.ri = 0;
  ret.pos = 0;
  ret.closed = false;
  return ret;
}

// wuffs_base__token_buffer__compact moves any written but unread tokens to the
// start of the buffer.
static inline void  //
wuffs_base__token_buffer__compact(wuffs_base__token_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 n = buf->meta.wi - buf->meta.ri;
  if (n != 0) {
    memmove(buf->data.ptr, buf->data.ptr + buf->meta.ri,
            n * sizeof(wuffs_base__token));
  }
  buf->meta.wi = n;
  buf->meta.ri = 0;
}

static inline uint64_t  //
wuffs_base__token_buffer__reader_available(
    const wuffs_base__token_buffer* buf) {
  return buf ? buf->meta.wi - buf->meta.ri : 0;
}

static inline uint64_t  //
wuffs_base__token_buffer__reader_token_position(
    const wuffs_base__token_buffer* buf) {
  return buf ? wuffs_base__u64__sat_add(buf->meta.pos, buf->meta.ri) : 0;
}

static inline uint64_t  //
wuffs_base__token_buffer__writer_available(
    const wuffs_base__token_buffer* buf) {
  return buf ? buf->data.len - buf->meta.wi : 0;
}

static inline uint64_t  //
wuffs_base__token_buffer__writer_token_position(
    const wuffs_base__token_buffer* buf) {
  return buf ? wuffs_base__u64__sat_add(buf->meta.pos, buf->meta.wi) : 0;
}

#ifdef __cplusplus

inline void  //
wuffs_base__token_buffer::compact() {
  wuffs_base__token_buffer__compact(this);
}

inline uint64_t  //
wuffs_base__token_buffer::reader_available() const {
  return wuffs_base__token_buffer__reader_available(this);
}

inline uint64_t  //
wuffs_base__token_buffer::reader_token_position() const {
  return wuffs_base__token_buffer__reader_token_position(this);
}

inline uint64_t  //
wuffs_base__token_buffer::writer_available() const {
  return wuffs_base__token_buffer__writer_available(this);
}

inline uint64_t  //
wuffs_base__token_buffer::writer_token_position() const {
  return wuffs_base__token_buffer__writer_token_position(this);
}

#endif  // __cplusplus