gen/h/std/adler32.h

#ifndef WUFFS_INCLUDE_GUARD__ADLER32
#define WUFFS_INCLUDE_GUARD__ADLER32

// Code generated by wuffs-c. DO NOT EDIT.

#ifndef WUFFS_INCLUDE_GUARD__BASE_PUBLIC
#define WUFFS_INCLUDE_GUARD__BASE_PUBLIC

// Copyright 2017 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.

#include <stdbool.h>
#include <stdint.h>
#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

// Wuffs assumes that:
//  - converting a uint32_t to a size_t will never overflow.
//  - converting a size_t to a uint64_t will never overflow.
#ifdef __WORDSIZE
#if (__WORDSIZE != 32) && (__WORDSIZE != 64)
#error "Wuffs requires a word size of either 32 or 64 bits"
#endif
#endif

// WUFFS_VERSION is the major.minor.patch version, as per https://semver.org/,
// as a uint64_t. The major number is the high 32 bits. The minor number is the
// middle 16 bits. The patch number is the low 16 bits. The version extension
// (such as "", "beta" or "rc.1") is part of the string representation (such as
// "1.2.3-beta") but not the uint64_t representation.
//
// All three of major, minor and patch being zero means that this is a
// work-in-progress version, not a release version, and has no backwards or
// forwards compatibility guarantees.
//
// !! Some code generation programs can override WUFFS_VERSION.
#define WUFFS_VERSION ((uint64_t)0)
#define WUFFS_VERSION_MAJOR ((uint64_t)0)
#define WUFFS_VERSION_MINOR ((uint64_t)0)
#define WUFFS_VERSION_PATCH ((uint64_t)0)
#define WUFFS_VERSION_EXTENSION ""
#define WUFFS_VERSION_STRING "0.0.0"

// wuffs_base__empty_struct is used when a Wuffs function returns an empty
// struct. In C, if a function f returns void, you can't say "x = f()", but in
// Wuffs, if a function g returns empty, you can say "y = g()".
typedef struct {
  // private_impl is a placeholder field. It isn't explicitly used, except that
  // without it, the sizeof a struct with no fields can differ across C/C++
  // compilers, and it is undefined behavior in C99. For example, gcc says that
  // the sizeof an empty struct is 0, and g++ says that it is 1. This leads to
  // ABI incompatibility if a Wuffs .c file is processed by one compiler and
  // its .h file with another compiler.
  //
  // Instead, we explicitly insert an otherwise unused field, so that the
  // sizeof this struct is always 1.
  uint8_t private_impl;
} wuffs_base__empty_struct;

// wuffs_base__utility is a placeholder receiver type. It enables what Java
// calls static methods, as opposed to regular methods.
typedef struct {
  // private_impl is a placeholder field. It isn't explicitly used, except that
  // without it, the sizeof a struct with no fields can differ across C/C++
  // compilers, and it is undefined behavior in C99. For example, gcc says that
  // the sizeof an empty struct is 0, and g++ says that it is 1. This leads to
  // ABI incompatibility if a Wuffs .c file is processed by one compiler and
  // its .h file with another compiler.
  //
  // Instead, we explicitly insert an otherwise unused field, so that the
  // sizeof this struct is always 1.
  uint8_t private_impl;
} wuffs_base__utility;

// --------

// A status code is either zero (OK), positive (a recoverable suspension or
// pause in processing) or negative (a non-recoverable error). Its bits:
//  - bit        31 (the sign bit) indicates unrecoverable-ness: an error.
//  - bits 30 .. 24 are a package-namespaced numeric code
//  - bits 23 .. 21 are reserved.
//  - bits 20 ..  0 are the packageid (a namespace) as a base38 value.
//
// Do not manipulate these bits directly; they are private implementation
// details. Use methods such as wuffs_base__status__is_error instead.
typedef int32_t wuffs_base__status;

#define WUFFS_BASE__STATUS_OK 0                                    // 0x00000000
#define WUFFS_BASE__ERROR_BAD_WUFFS_VERSION -16777216              // 0xFF000000
#define WUFFS_BASE__ERROR_BAD_SIZEOF_RECEIVER -33554432            // 0xFE000000
#define WUFFS_BASE__ERROR_BAD_RECEIVER -50331648                   // 0xFD000000
#define WUFFS_BASE__ERROR_BAD_ARGUMENT -67108864                   // 0xFC000000
#define WUFFS_BASE__ERROR_BAD_ARGUMENT_LENGTH_TOO_SHORT -67108864  // 0xFC000000
#define WUFFS_BASE__ERROR_CHECK_WUFFS_VERSION_NOT_CALLED \
  -268435456  // 0xF0000000
#define WUFFS_BASE__ERROR_CHECK_WUFFS_VERSION_CALLED_TWICE \
  -285212672                                                     // 0xEF000000
#define WUFFS_BASE__ERROR_INVALID_CALL_SEQUENCE -301989888       // 0xEE000000
#define WUFFS_BASE__ERROR_CANNOT_RETURN_A_SUSPENSION -536870912  // 0xE0000000
#define WUFFS_BASE__ERROR_INVALID_I_O_OPERATION -805306368       // 0xD0000000
#define WUFFS_BASE__ERROR_UNEXPECTED_EOF -822083584              // 0xCF000000
#define WUFFS_BASE__ERROR_CLOSED_FOR_WRITES -838860800           // 0xCE000000
#define WUFFS_BASE__SUSPENSION_END_OF_DATA 16777216              // 0x01000000
#define WUFFS_BASE__SUSPENSION_SHORT_READ 33554432               // 0x02000000
#define WUFFS_BASE__SUSPENSION_SHORT_WRITE 50331648              // 0x03000000

static inline bool wuffs_base__status__is_error(wuffs_base__status s) {
  return s < 0;
}

static inline bool wuffs_base__status__is_ok(wuffs_base__status s) {
  return s == 0;
}

static inline bool wuffs_base__status__is_suspension(wuffs_base__status s) {
  return s > 0;
}

const char* wuffs_base__status__string(wuffs_base__status s);

// --------

// Flicks are a unit of time. One flick (frame-tick) is 1 / 705_600_000 of a
// second. See https://github.com/OculusVR/Flicks
typedef int64_t wuffs_base__flicks;

#define WUFFS_BASE__FLICKS_PER_SECOND ((uint64_t)705600000)
#define WUFFS_BASE__FLICKS_PER_MILLISECOND ((uint64_t)705600)

// ---------------- Numeric Types

static inline uint8_t wuffs_base__u8__min(uint8_t x, uint8_t y) {
  return x < y ? x : y;
}

static inline uint8_t wuffs_base__u8__max(uint8_t x, uint8_t y) {
  return x > y ? x : y;
}

static inline uint16_t wuffs_base__u16__min(uint16_t x, uint16_t y) {
  return x < y ? x : y;
}

static inline uint16_t wuffs_base__u16__max(uint16_t x, uint16_t y) {
  return x > y ? x : y;
}

static inline uint32_t wuffs_base__u32__min(uint32_t x, uint32_t y) {
  return x < y ? x : y;
}

static inline uint32_t wuffs_base__u32__max(uint32_t x, uint32_t y) {
  return x > y ? x : y;
}

static inline uint64_t wuffs_base__u64__min(uint64_t x, uint64_t y) {
  return x < y ? x : y;
}

static inline uint64_t wuffs_base__u64__max(uint64_t x, uint64_t y) {
  return x > y ? x : y;
}

// --------

// Saturating arithmetic (sat_add, sat_sub) branchless bit-twiddling algorithms
// are per https://locklessinc.com/articles/sat_arithmetic/
//
// It is important that the underlying types are unsigned integers, as signed
// integer arithmetic overflow is undefined behavior in C.

static inline uint8_t wuffs_base__u8__sat_add(uint8_t x, uint8_t y) {
  uint8_t res = x + y;
  res |= -(res < x);
  return res;
}

static inline uint8_t wuffs_base__u8__sat_sub(uint8_t x, uint8_t y) {
  uint8_t res = x - y;
  res &= -(res <= x);
  return res;
}

static inline uint16_t wuffs_base__u16__sat_add(uint16_t x, uint16_t y) {
  uint16_t res = x + y;
  res |= -(res < x);
  return res;
}

static inline uint16_t wuffs_base__u16__sat_sub(uint16_t x, uint16_t y) {
  uint16_t res = x - y;
  res &= -(res <= x);
  return res;
}

static inline uint32_t wuffs_base__u32__sat_add(uint32_t x, uint32_t y) {
  uint32_t res = x + y;
  res |= -(res < x);
  return res;
}

static inline uint32_t wuffs_base__u32__sat_sub(uint32_t x, uint32_t y) {
  uint32_t res = x - y;
  res &= -(res <= x);
  return res;
}

static inline uint64_t wuffs_base__u64__sat_add(uint64_t x, uint64_t y) {
  uint64_t res = x + y;
  res |= -(res < x);
  return res;
}

static inline uint64_t wuffs_base__u64__sat_sub(uint64_t x, uint64_t y) {
  uint64_t res = x - y;
  res &= -(res <= x);
  return res;
}

// --------

// Clang also defines "__GNUC__".

static inline uint16_t wuffs_base__u16__byte_swapped(uint16_t x) {
#if defined(__GNUC__)
  return __builtin_bswap16(x);
#else
  return (x >> 8) | (x << 8);
#endif
}

static inline uint32_t wuffs_base__u32__byte_swapped(uint32_t x) {
#if defined(__GNUC__)
  return __builtin_bswap32(x);
#else
  static const uint32_t mask8 = 0x00FF00FF;
  x = ((x >> 8) & mask8) | ((x & mask8) << 8);
  return (x >> 16) | (x << 16);
#endif
}

static inline uint64_t wuffs_base__u64__byte_swapped(uint64_t x) {
#if defined(__GNUC__)
  return __builtin_bswap64(x);
#else
  static const uint64_t mask8 = 0x00FF00FF00FF00FF;
  static const uint64_t mask16 = 0x0000FFFF0000FFFF;
  x = ((x >> 8) & mask8) | ((x & mask8) << 8);
  x = ((x >> 16) & mask16) | ((x & mask16) << 16);
  return (x >> 32) | (x << 32);
#endif
}

// ---------------- Slices and Tables

// WUFFS_BASE__SLICE is a 1-dimensional buffer.
//
// A value with all fields NULL or zero is a valid, empty slice.
#define WUFFS_BASE__SLICE(T) \
  struct {                   \
    T* ptr;                  \
    size_t len;              \
  }

// WUFFS_BASE__TABLE is a 2-dimensional buffer.
//
// A value with all fields NULL or zero is a valid, empty table.
#define WUFFS_BASE__TABLE(T) \
  struct {                   \
    T* ptr;                  \
    size_t width;            \
    size_t height;           \
    size_t stride;           \
  }

typedef WUFFS_BASE__SLICE(uint8_t) wuffs_base__slice_u8;
typedef WUFFS_BASE__SLICE(uint16_t) wuffs_base__slice_u16;
typedef WUFFS_BASE__SLICE(uint32_t) wuffs_base__slice_u32;
typedef WUFFS_BASE__SLICE(uint64_t) wuffs_base__slice_u64;

typedef WUFFS_BASE__TABLE(uint8_t) wuffs_base__table_u8;
typedef WUFFS_BASE__TABLE(uint16_t) wuffs_base__table_u16;
typedef WUFFS_BASE__TABLE(uint32_t) wuffs_base__table_u32;
typedef WUFFS_BASE__TABLE(uint64_t) wuffs_base__table_u64;

// ---------------- Ranges and Rects

// Ranges are either inclusive ("range_ii") or exclusive ("range_ie") on the
// high end. Both the "ii" and "ie" flavors are useful in practice.
//
// The "ei" and "ee" flavors also exist in theory, but aren't widely used. In
// Wuffs, the low end is always inclusive.
//
// The "ii" (closed interval) flavor is useful when refining e.g. "the set of
// all uint32_t values" to a contiguous subset: "uint32_t values in the closed
// interval [M, N]", for uint32_t values M and N. An unrefined type (in other
// words, the set of all uint32_t values) is not representable in the "ie"
// flavor because if N equals ((1<<32) - 1) then (N + 1) will overflow.
//
// On the other hand, the "ie" (half-open interval) flavor is recommended by
// Dijkstra's "Why numbering should start at zero" at
// http://www.cs.utexas.edu/users/EWD/ewd08xx/EWD831.PDF and a further
// discussion of motivating rationale is at
// https://www.quora.com/Why-are-Python-ranges-half-open-exclusive-instead-of-closed-inclusive
//
// For example, with "ie", the number of elements in "uint32_t values in the
// half-open interval [M, N)" is equal to max(0, N-M). Furthermore, that number
// of elements (in one dimension, a length, in two dimensions, a width or
// height) is itself representable as a uint32_t without overflow, again for
// uint32_t values M and N. In the contrasting "ii" flavor, the length of the
// closed interval [0, (1<<32) - 1] is 1<<32, which cannot be represented as a
// uint32_t. In Wuffs, because of this potential overflow, the "ie" flavor has
// length / width / height methods, but the "ii" flavor does not.
//
// It is valid for min > max (for range_ii) or for min >= max (for range_ie),
// in which case the range is empty. There are multiple representations of an
// empty range.

typedef struct {
  uint32_t min_incl;
  uint32_t max_incl;
} wuffs_base__range_ii_u32;

static inline bool wuffs_base__range_ii_u32__is_empty(
    wuffs_base__range_ii_u32 r) {
  return r.min_incl > r.max_incl;
}

static inline bool wuffs_base__range_ii_u32__equals(
    wuffs_base__range_ii_u32 r,
    wuffs_base__range_ii_u32 s) {
  return (r.min_incl == s.min_incl && r.max_incl == s.max_incl) ||
         (wuffs_base__range_ii_u32__is_empty(r) &&
          wuffs_base__range_ii_u32__is_empty(s));
}

static inline bool wuffs_base__range_ii_u32__contains(
    wuffs_base__range_ii_u32 r,
    uint32_t x) {
  return (r.min_incl <= x) && (x <= r.max_incl);
}

static inline wuffs_base__range_ii_u32 wuffs_base__range_ii_u32__intersection(
    wuffs_base__range_ii_u32 r,
    wuffs_base__range_ii_u32 s) {
  r.min_incl = wuffs_base__u32__max(r.min_incl, s.min_incl);
  r.max_incl = wuffs_base__u32__min(r.max_incl, s.max_incl);
  return r;
}

static inline wuffs_base__range_ii_u32 wuffs_base__range_ii_u32__union(
    wuffs_base__range_ii_u32 r,
    wuffs_base__range_ii_u32 s) {
  if (wuffs_base__range_ii_u32__is_empty(r)) {
    return s;
  }
  if (wuffs_base__range_ii_u32__is_empty(s)) {
    return r;
  }
  r.min_incl = wuffs_base__u32__min(r.min_incl, s.min_incl);
  r.max_incl = wuffs_base__u32__max(r.max_incl, s.max_incl);
  return r;
}

// --------

typedef struct {
  uint32_t min_incl;
  uint32_t max_excl;
} wuffs_base__range_ie_u32;

static inline bool wuffs_base__range_ie_u32__is_empty(
    wuffs_base__range_ie_u32 r) {
  return r.min_incl >= r.max_excl;
}

static inline bool wuffs_base__range_ie_u32__equals(
    wuffs_base__range_ie_u32 r,
    wuffs_base__range_ie_u32 s) {
  return (r.min_incl == s.min_incl && r.max_excl == s.max_excl) ||
         (wuffs_base__range_ie_u32__is_empty(r) &&
          wuffs_base__range_ie_u32__is_empty(s));
}

static inline bool wuffs_base__range_ie_u32__contains(
    wuffs_base__range_ie_u32 r,
    uint32_t x) {
  return (r.min_incl <= x) && (x < r.max_excl);
}

static inline wuffs_base__range_ie_u32 wuffs_base__range_ie_u32__intersection(
    wuffs_base__range_ie_u32 r,
    wuffs_base__range_ie_u32 s) {
  r.min_incl = wuffs_base__u32__max(r.min_incl, s.min_incl);
  r.max_excl = wuffs_base__u32__min(r.max_excl, s.max_excl);
  return r;
}

static inline wuffs_base__range_ie_u32 wuffs_base__range_ie_u32__union(
    wuffs_base__range_ie_u32 r,
    wuffs_base__range_ie_u32 s) {
  if (wuffs_base__range_ie_u32__is_empty(r)) {
    return s;
  }
  if (wuffs_base__range_ie_u32__is_empty(s)) {
    return r;
  }
  r.min_incl = wuffs_base__u32__min(r.min_incl, s.min_incl);
  r.max_excl = wuffs_base__u32__max(r.max_excl, s.max_excl);
  return r;
}

static inline uint32_t wuffs_base__range_ie_u32__length(
    wuffs_base__range_ie_u32 r) {
  return wuffs_base__u32__sat_sub(r.max_excl, r.min_incl);
}

// --------

typedef struct {
  uint64_t min_incl;
  uint64_t max_incl;
} wuffs_base__range_ii_u64;

static inline bool wuffs_base__range_ii_u64__is_empty(
    wuffs_base__range_ii_u64 r) {
  return r.min_incl > r.max_incl;
}

static inline bool wuffs_base__range_ii_u64__equals(
    wuffs_base__range_ii_u64 r,
    wuffs_base__range_ii_u64 s) {
  return (r.min_incl == s.min_incl && r.max_incl == s.max_incl) ||
         (wuffs_base__range_ii_u64__is_empty(r) &&
          wuffs_base__range_ii_u64__is_empty(s));
}

static inline bool wuffs_base__range_ii_u64__contains(
    wuffs_base__range_ii_u64 r,
    uint64_t x) {
  return (r.min_incl <= x) && (x <= r.max_incl);
}

static inline wuffs_base__range_ii_u64 wuffs_base__range_ii_u64__intersection(
    wuffs_base__range_ii_u64 r,
    wuffs_base__range_ii_u64 s) {
  r.min_incl = wuffs_base__u64__max(r.min_incl, s.min_incl);
  r.max_incl = wuffs_base__u64__min(r.max_incl, s.max_incl);
  return r;
}

static inline wuffs_base__range_ii_u64 wuffs_base__range_ii_u64__union(
    wuffs_base__range_ii_u64 r,
    wuffs_base__range_ii_u64 s) {
  if (wuffs_base__range_ii_u64__is_empty(r)) {
    return s;
  }
  if (wuffs_base__range_ii_u64__is_empty(s)) {
    return r;
  }
  r.min_incl = wuffs_base__u64__min(r.min_incl, s.min_incl);
  r.max_incl = wuffs_base__u64__max(r.max_incl, s.max_incl);
  return r;
}

// --------

typedef struct {
  uint64_t min_incl;
  uint64_t max_excl;
} wuffs_base__range_ie_u64;

static inline bool wuffs_base__range_ie_u64__is_empty(
    wuffs_base__range_ie_u64 r) {
  return r.min_incl >= r.max_excl;
}

static inline bool wuffs_base__range_ie_u64__equals(
    wuffs_base__range_ie_u64 r,
    wuffs_base__range_ie_u64 s) {
  return (r.min_incl == s.min_incl && r.max_excl == s.max_excl) ||
         (wuffs_base__range_ie_u64__is_empty(r) &&
          wuffs_base__range_ie_u64__is_empty(s));
}

static inline bool wuffs_base__range_ie_u64__contains(
    wuffs_base__range_ie_u64 r,
    uint64_t x) {
  return (r.min_incl <= x) && (x < r.max_excl);
}

static inline wuffs_base__range_ie_u64 wuffs_base__range_ie_u64__intersection(
    wuffs_base__range_ie_u64 r,
    wuffs_base__range_ie_u64 s) {
  r.min_incl = wuffs_base__u64__max(r.min_incl, s.min_incl);
  r.max_excl = wuffs_base__u64__min(r.max_excl, s.max_excl);
  return r;
}

static inline wuffs_base__range_ie_u64 wuffs_base__range_ie_u64__union(
    wuffs_base__range_ie_u64 r,
    wuffs_base__range_ie_u64 s) {
  if (wuffs_base__range_ie_u64__is_empty(r)) {
    return s;
  }
  if (wuffs_base__range_ie_u64__is_empty(s)) {
    return r;
  }
  r.min_incl = wuffs_base__u64__min(r.min_incl, s.min_incl);
  r.max_excl = wuffs_base__u64__max(r.max_excl, s.max_excl);
  return r;
}

static inline uint64_t wuffs_base__range_ie_u64__length(
    wuffs_base__range_ie_u64 r) {
  return wuffs_base__u64__sat_sub(r.max_excl, r.min_incl);
}

// --------

// wuffs_base__rect_ii_u32 is a rectangle (a 2-dimensional range) on the
// integer grid. The "ii" means that the bounds are inclusive on the low end
// and inclusive on the high end. It contains all points (x, y) such that
// ((min_incl_x <= x) && (x <= max_incl_x)) and likewise for y.
//
// It is valid for min > max, in which case the rectangle is empty. There are
// multiple representations of an empty rectangle.
//
// The X and Y axes increase right and down.
typedef struct {
  uint32_t min_incl_x;
  uint32_t min_incl_y;
  uint32_t max_incl_x;
  uint32_t max_incl_y;
} wuffs_base__rect_ii_u32;

static inline bool wuffs_base__rect_ii_u32__is_empty(
    wuffs_base__rect_ii_u32 r) {
  return (r.min_incl_x > r.max_incl_x) || (r.min_incl_y > r.max_incl_y);
}

static inline bool wuffs_base__rect_ii_u32__equals(wuffs_base__rect_ii_u32 r,
                                                   wuffs_base__rect_ii_u32 s) {
  return (r.min_incl_x == s.min_incl_x && r.min_incl_y == s.min_incl_y &&
          r.max_incl_x == s.max_incl_x && r.max_incl_y == s.max_incl_y) ||
         (wuffs_base__rect_ii_u32__is_empty(r) &&
          wuffs_base__rect_ii_u32__is_empty(s));
}

static inline bool wuffs_base__rect_ii_u32__contains(wuffs_base__rect_ii_u32 r,
                                                     uint32_t x,
                                                     uint32_t y) {
  return (r.min_incl_x <= x) && (x <= r.max_incl_x) && (r.min_incl_y <= y) &&
         (y <= r.max_incl_y);
}

static inline wuffs_base__rect_ii_u32 wuffs_base__rect_ii_u32__intersection(
    wuffs_base__rect_ii_u32 r,
    wuffs_base__rect_ii_u32 s) {
  r.min_incl_x = wuffs_base__u32__max(r.min_incl_x, s.min_incl_x);
  r.min_incl_y = wuffs_base__u32__max(r.min_incl_y, s.min_incl_y);
  r.max_incl_x = wuffs_base__u32__min(r.max_incl_x, s.max_incl_x);
  r.max_incl_y = wuffs_base__u32__min(r.max_incl_y, s.max_incl_y);
  return r;
}

static inline wuffs_base__rect_ii_u32 wuffs_base__rect_ii_u32__union(
    wuffs_base__rect_ii_u32 r,
    wuffs_base__rect_ii_u32 s) {
  if (wuffs_base__rect_ii_u32__is_empty(r)) {
    return s;
  }
  if (wuffs_base__rect_ii_u32__is_empty(s)) {
    return r;
  }
  r.min_incl_x = wuffs_base__u32__min(r.min_incl_x, s.min_incl_x);
  r.min_incl_y = wuffs_base__u32__min(r.min_incl_y, s.min_incl_y);
  r.max_incl_x = wuffs_base__u32__max(r.max_incl_x, s.max_incl_x);
  r.max_incl_y = wuffs_base__u32__max(r.max_incl_y, s.max_incl_y);
  return r;
}

// --------

// wuffs_base__rect_ie_u32 is a rectangle (a 2-dimensional range) on the
// integer grid. The "ie" means that the bounds are inclusive on the low end
// and exclusive on the high end. It contains all points (x, y) such that
// ((min_incl_x <= x) && (x < max_excl_x)) and likewise for y.
//
// It is valid for min >= max, in which case the rectangle is empty. There are
// multiple representations of an empty rectangle, including a value with all
// fields zero.
//
// The X and Y axes increase right and down.
typedef struct {
  uint32_t min_incl_x;
  uint32_t min_incl_y;
  uint32_t max_excl_x;
  uint32_t max_excl_y;
} wuffs_base__rect_ie_u32;

static inline bool wuffs_base__rect_ie_u32__is_empty(
    wuffs_base__rect_ie_u32 r) {
  return (r.min_incl_x >= r.max_excl_x) || (r.min_incl_y >= r.max_excl_y);
}

static inline bool wuffs_base__rect_ie_u32__equals(wuffs_base__rect_ie_u32 r,
                                                   wuffs_base__rect_ie_u32 s) {
  return (r.min_incl_x == s.min_incl_x && r.min_incl_y == s.min_incl_y &&
          r.max_excl_x == s.max_excl_x && r.max_excl_y == s.max_excl_y) ||
         (wuffs_base__rect_ie_u32__is_empty(r) &&
          wuffs_base__rect_ie_u32__is_empty(s));
}

static inline bool wuffs_base__rect_ie_u32__contains(wuffs_base__rect_ie_u32 r,
                                                     uint32_t x,
                                                     uint32_t y) {
  return (r.min_incl_x <= x) && (x < r.max_excl_x) && (r.min_incl_y <= y) &&
         (y < r.max_excl_y);
}

static inline wuffs_base__rect_ie_u32 wuffs_base__rect_ie_u32__intersection(
    wuffs_base__rect_ie_u32 r,
    wuffs_base__rect_ie_u32 s) {
  r.min_incl_x = wuffs_base__u32__max(r.min_incl_x, s.min_incl_x);
  r.min_incl_y = wuffs_base__u32__max(r.min_incl_y, s.min_incl_y);
  r.max_excl_x = wuffs_base__u32__min(r.max_excl_x, s.max_excl_x);
  r.max_excl_y = wuffs_base__u32__min(r.max_excl_y, s.max_excl_y);
  return r;
}

static inline wuffs_base__rect_ie_u32 wuffs_base__rect_ie_u32__union(
    wuffs_base__rect_ie_u32 r,
    wuffs_base__rect_ie_u32 s) {
  if (wuffs_base__rect_ie_u32__is_empty(r)) {
    return s;
  }
  if (wuffs_base__rect_ie_u32__is_empty(s)) {
    return r;
  }
  r.min_incl_x = wuffs_base__u32__min(r.min_incl_x, s.min_incl_x);
  r.min_incl_y = wuffs_base__u32__min(r.min_incl_y, s.min_incl_y);
  r.max_excl_x = wuffs_base__u32__max(r.max_excl_x, s.max_excl_x);
  r.max_excl_y = wuffs_base__u32__max(r.max_excl_y, s.max_excl_y);
  return r;
}

static inline uint32_t wuffs_base__rect_ie_u32__width(
    wuffs_base__rect_ie_u32 r) {
  return wuffs_base__u32__sat_sub(r.max_excl_x, r.min_incl_x);
}

static inline uint32_t wuffs_base__rect_ie_u32__height(
    wuffs_base__rect_ie_u32 r) {
  return wuffs_base__u32__sat_sub(r.max_excl_y, r.min_incl_y);
}

// ---------------- I/O

// wuffs_base__io_buffer is a 1-dimensional buffer (a pointer and length), plus
// additional indexes into that buffer, plus an opened / closed flag.
//
// A value with all fields NULL or zero is a valid, empty buffer.
typedef struct {
  uint8_t* ptr;  // Pointer.
  size_t len;    // Length.
  size_t wi;     // Write index. Invariant: wi <= len.
  size_t ri;     // Read  index. Invariant: ri <= wi.
  bool closed;   // No further writes are expected.
} wuffs_base__io_buffer;

typedef struct {
  // Do not access the private_impl's fields directly. There is no API/ABI
  // compatibility or safety guarantee if you do so.
  struct {
    wuffs_base__io_buffer* buf;
    // The bounds values are typically NULL, when created by the Wuffs public
    // API. NULL means that the callee substitutes the implicit bounds derived
    // from buf.
    uint8_t* bounds[2];
  } private_impl;
} wuffs_base__io_reader;

typedef struct {
  // Do not access the private_impl's fields directly. There is no API/ABI
  // compatibility or safety guarantee if you do so.
  struct {
    wuffs_base__io_buffer* buf;
    // The bounds values are typically NULL, when created by the Wuffs public
    // API. NULL means that the callee substitutes the implicit bounds derived
    // from buf.
    uint8_t* bounds[2];
  } private_impl;
} wuffs_base__io_writer;

// 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->ri == 0)) {
    return;
  }
  size_t n = buf->wi - buf->ri;
  if (n != 0) {
    memmove(buf->ptr, buf->ptr + buf->ri, n);
  }
  buf->wi = n;
  buf->ri = 0;
}

static inline wuffs_base__io_reader wuffs_base__io_buffer__reader(
    wuffs_base__io_buffer* buf) {
  wuffs_base__io_reader ret = ((wuffs_base__io_reader){});
  ret.private_impl.buf = buf;
  return ret;
}

static inline wuffs_base__io_writer wuffs_base__io_buffer__writer(
    wuffs_base__io_buffer* buf) {
  wuffs_base__io_writer ret = ((wuffs_base__io_writer){});
  ret.private_impl.buf = buf;
  return ret;
}

// ---------------- Images

// wuffs_base__color_u32argb is an 8 bit per channel Alpha, Red, Green, Blue
// color, as a uint32_t value. It is in word order, not byte order: its value
// is always 0xAARRGGBB, regardless of endianness. It uses premultiplied alpha.
typedef uint32_t wuffs_base__color_u32argb;

// --------

// wuffs_base__pixel_format encodes the format of the bytes that constitute an
// image frame's pixel data. Its bits:
//  - bit        31  is reserved.
//  - bits 30 .. 28 encodes color (and channel order, in terms of memory).
//  - bits 27 .. 26 are reserved.
//  - bits 25 .. 24 encodes transparency.
//  - bit        23 indicates big-endian/MSB-first (as opposed to little/LSB).
//  - bit        22 indicates floating point (as opposed to integer).
//  - bits 21 .. 20 are the number of planes, minus 1. Zero means packed.
//  - bits 19 .. 16 encodes the number of bits (depth) in an index value.
//                  Zero means direct, not palette-indexed.
//  - bits 15 .. 12 encodes the number of bits (depth) in the 3rd channel.
//  - bits 11 ..  8 encodes the number of bits (depth) in the 2nd channel.
//  - bits  7 ..  4 encodes the number of bits (depth) in the 1st channel.
//  - bits  3 ..  0 encodes the number of bits (depth) in the 0th channel.
//
// The bit fields of a wuffs_base__pixel_format are not independent. For
// example, the number of planes should not be greater than the number of
// channels. Similarly, bits 15..4 are unused (and should be zero) if bits
// 31..24 (color and transparency) together imply only 1 channel (gray, no
// alpha) and floating point samples should mean a bit depth of 16, 32 or 64.
//
// Formats hold between 1 and 4 channels. For example: Y (1 channel: gray), YA
// (2 channels: gray and alpha), BGR (3 channels: blue, green, red) or CMYK (4
// channels: cyan, magenta, yellow, black).
//
// For direct formats with N > 1 channels, those channels can be laid out in
// either 1 (packed) or N (planar) planes. For example, RGBA data is usually
// packed, but YUV data is usually planar, due to chroma subsampling (for
// details, see the wuffs_base__pixel_subsampling type). For indexed formats,
// the palette (always 256 × 4 bytes) holds up to 4 packed bytes of color data
// per index value, and there is only 1 plane (for the index). The distance
// between successive palette elements is always 4 bytes.
//
// The color field is encoded in 3 bits:
//  - 0 means                 A (Alpha).
//  - 1 means   Y       or   YA (Gray, Alpha).
//  - 2 means BGR, BGRX or BGRA (Blue, Green, Red, X-padding or Alpha).
//  - 3 means RGB, RGBX or RGBA (Red, Green, Blue, X-padding or Alpha).
//  - 4 means YUV       or YUVA (Luma, Chroma-blue, Chroma-red, Alpha).
//  - 5 means CMY       or CMYK (Cyan, Magenta, Yellow, Black).
//  - all other values are reserved.
//
// In Wuffs, channels are given in memory order (also known as byte order),
// regardless of endianness, since the C type for the pixel data is an array of
// bytes, not an array of uint32_t. For example, packed BGRA with 8 bits per
// channel means that the bytes in memory are always Blue, Green, Red then
// Alpha. On big-endian systems, that is the uint32_t 0xBBGGRRAA. On
// little-endian, 0xAARRGGBB.
//
// When the color field (3 bits) encodes multiple options, the transparency
// field (2 bits) distinguishes them:
//  - 0 means fully opaque, no extra channels
//  - 1 means fully opaque, one extra channel (X or K, padding or black).
//  - 2 means one extra alpha channel, other channels are non-premultiplied.
//  - 3 means one extra alpha channel, other channels are     premultiplied.
//
// The zero wuffs_base__pixel_format value is an invalid pixel format, as it is
// invalid to combine the zero color (alpha only) with the zero transparency.
//
// Bit depth is encoded in 4 bits:
//  -  0 means the channel or index is unused.
//  -  x means a bit depth of  x, for x in the range 1..8.
//  -  9 means a bit depth of 10.
//  - 10 means a bit depth of 12.
//  - 11 means a bit depth of 16.
//  - 12 means a bit depth of 24.
//  - 13 means a bit depth of 32.
//  - 14 means a bit depth of 48.
//  - 15 means a bit depth of 64.
//
// For example, wuffs_base__pixel_format 0x3280BBBB is a natural format for
// decoding a PNG image - network byte order (also known as big-endian),
// packed, non-premultiplied alpha - that happens to be 16-bit-depth truecolor
// with alpha (RGBA). In memory order:
//
//  ptr+0  ptr+1  ptr+2  ptr+3  ptr+4  ptr+5  ptr+6  ptr+7
//  Rhi    Rlo    Ghi    Glo    Bhi    Blo    Ahi    Alo
//
// For example, the value wuffs_base__pixel_format 0x20000565 means BGR with no
// alpha or padding, 5/6/5 bits for blue/green/red, packed 2 bytes per pixel,
// laid out LSB-first in memory order:
//
//  ptr+0...........  ptr+1...........
//  MSB          LSB  MSB          LSB
//  G₂G₁G₀B₄B₃B₂B₁B₀  R₄R₃R₂R₁R₀G₅G₄G₃
//
// On little-endian systems (but not big-endian), this Wuffs pixel format value
// (0x20000565) corresponds to the Cairo library's CAIRO_FORMAT_RGB16_565, the
// SDL2 (Simple DirectMedia Layer 2) library's SDL_PIXELFORMAT_RGB565 and the
// Skia library's kRGB_565_SkColorType. Note BGR in Wuffs versus RGB in the
// other libraries.
//
// Regardless of endianness, this Wuffs pixel format value (0x20000565)
// corresponds to the V4L2 (Video For Linux 2) library's V4L2_PIX_FMT_RGB565
// and the Wayland-DRM library's WL_DRM_FORMAT_RGB565.
//
// Different software libraries name their pixel formats (and especially their
// channel order) either according to memory layout or as bits of a native
// integer type like uint32_t. The two conventions differ because of a system's
// endianness. As mentioned earlier, Wuffs pixel formats are always in memory
// order. More detail of other software libraries' naming conventions is in the
// Pixel Format Guide at https://afrantzis.github.io/pixel-format-guide/
//
// Do not manipulate these bits directly; they are private implementation
// details. Use methods such as wuffs_base__pixel_format__num_planes instead.
typedef uint32_t wuffs_base__pixel_format;

// Common 8-bit-depth pixel formats. This list is not exhaustive; not all valid
// wuffs_base__pixel_format values are present.

#define WUFFS_BASE__PIXEL_FORMAT__INVALID ((wuffs_base__pixel_format)0x00000000)

#define WUFFS_BASE__PIXEL_FORMAT__A ((wuffs_base__pixel_format)0x02000008)

#define WUFFS_BASE__PIXEL_FORMAT__Y ((wuffs_base__pixel_format)0x10000008)
#define WUFFS_BASE__PIXEL_FORMAT__YA_NONPREMUL \
  ((wuffs_base__pixel_format)0x12000008)
#define WUFFS_BASE__PIXEL_FORMAT__YA_PREMUL \
  ((wuffs_base__pixel_format)0x13000008)

#define WUFFS_BASE__PIXEL_FORMAT__BGR ((wuffs_base__pixel_format)0x20000888)
#define WUFFS_BASE__PIXEL_FORMAT__BGRX ((wuffs_base__pixel_format)0x21008888)
#define WUFFS_BASE__PIXEL_FORMAT__BGRX_INDEXED \
  ((wuffs_base__pixel_format)0x21088888)
#define WUFFS_BASE__PIXEL_FORMAT__BGRA_NONPREMUL \
  ((wuffs_base__pixel_format)0x22008888)
#define WUFFS_BASE__PIXEL_FORMAT__BGRA_NONPREMUL_INDEXED \
  ((wuffs_base__pixel_format)0x22088888)
#define WUFFS_BASE__PIXEL_FORMAT__BGRA_PREMUL \
  ((wuffs_base__pixel_format)0x23008888)

#define WUFFS_BASE__PIXEL_FORMAT__RGB ((wuffs_base__pixel_format)0x30000888)
#define WUFFS_BASE__PIXEL_FORMAT__RGBX ((wuffs_base__pixel_format)0x31008888)
#define WUFFS_BASE__PIXEL_FORMAT__RGBX_INDEXED \
  ((wuffs_base__pixel_format)0x31088888)
#define WUFFS_BASE__PIXEL_FORMAT__RGBA_NONPREMUL \
  ((wuffs_base__pixel_format)0x32008888)
#define WUFFS_BASE__PIXEL_FORMAT__RGBA_NONPREMUL_INDEXED \
  ((wuffs_base__pixel_format)0x32088888)
#define WUFFS_BASE__PIXEL_FORMAT__RGBA_PREMUL \
  ((wuffs_base__pixel_format)0x33008888)

#define WUFFS_BASE__PIXEL_FORMAT__YUV ((wuffs_base__pixel_format)0x40200888)
#define WUFFS_BASE__PIXEL_FORMAT__YUVK ((wuffs_base__pixel_format)0x41308888)
#define WUFFS_BASE__PIXEL_FORMAT__YUVA_NONPREMUL \
  ((wuffs_base__pixel_format)0x42308888)

#define WUFFS_BASE__PIXEL_FORMAT__CMY ((wuffs_base__pixel_format)0x50200888)
#define WUFFS_BASE__PIXEL_FORMAT__CMYK ((wuffs_base__pixel_format)0x51308888)

static inline bool wuffs_base__pixel_format__is_valid(
    wuffs_base__pixel_format f) {
  return f != 0;
}

static inline bool wuffs_base__pixel_format__is_indexed(
    wuffs_base__pixel_format f) {
  return ((f >> 16) & 0x0F) != 0;
}

#define WUFFS_BASE__PIXEL_FORMAT__NUM_PLANES_MAX 4

static inline uint32_t wuffs_base__pixel_format__num_planes(
    wuffs_base__pixel_format f) {
  return f ? (((f >> 20) & 0x03) + 1) : 0;
}

typedef struct {
  wuffs_base__table_u8 planes[WUFFS_BASE__PIXEL_FORMAT__NUM_PLANES_MAX];
} wuffs_base__pixel_buffer;

// --------

// wuffs_base__pixel_subsampling encodes the mapping of pixel space coordinates
// (x, y) to pixel buffer indices (i, j). That mapping can differ for each
// plane p. For a depth of 8 bits (1 byte), the p'th plane's sample starts at
// (planes[p].ptr + (j * planes[p].stride) + i).
//
// For packed pixel formats, the mapping is trivial: i = x and j = y. For
// planar pixel formats, the mapping can differ due to chroma subsampling. For
// example, consider a three plane YUV pixel format with 4:2:2 subsampling. For
// the luma (Y) channel, there is one sample for every pixel, but for the
// chroma (U, V) channels, there is one sample for every two pixels: pairs of
// horizontally adjacent pixels form one macropixel, i = x / 2 and j == y. In
// general, for a given p:
//  - i = (x + bias_x) >> shift_x.
//  - j = (y + bias_y) >> shift_y.
// where biases and shifts are in the range 0..3 and 0..2 respectively.
//
// In general, the biases will be zero after decoding an image. However, making
// a sub-image may change the bias, since the (x, y) coordinates are relative
// to the sub-image's top-left origin, but the backing pixel buffers were
// created relative to the original image's origin.
//
// For each plane p, each of those four numbers (biases and shifts) are encoded
// in two bits, which combine to form an 8 bit unsigned integer:
//
//  e_p = (bias_x << 6) | (shift_x << 4) | (bias_y << 2) | (shift_y << 0)
//
// Those e_p values (e_0 for the first plane, e_1 for the second plane, etc)
// combine to form a wuffs_base__pixel_subsampling value:
//
//  pixsub = (e_3 << 24) | (e_2 << 16) | (e_1 << 8) | (e_0 << 0)
//
// Do not manipulate these bits directly; they are private implementation
// details. Use methods such as wuffs_base__pixel_subsampling__bias_x instead.
typedef uint32_t wuffs_base__pixel_subsampling;

#define WUFFS_BASE__PIXEL_SUBSAMPLING__NONE ((wuffs_base__pixel_subsampling)0)

#define WUFFS_BASE__PIXEL_SUBSAMPLING__444 \
  ((wuffs_base__pixel_subsampling)0x000000)
#define WUFFS_BASE__PIXEL_SUBSAMPLING__440 \
  ((wuffs_base__pixel_subsampling)0x010100)
#define WUFFS_BASE__PIXEL_SUBSAMPLING__422 \
  ((wuffs_base__pixel_subsampling)0x101000)
#define WUFFS_BASE__PIXEL_SUBSAMPLING__420 \
  ((wuffs_base__pixel_subsampling)0x111100)
#define WUFFS_BASE__PIXEL_SUBSAMPLING__411 \
  ((wuffs_base__pixel_subsampling)0x202000)
#define WUFFS_BASE__PIXEL_SUBSAMPLING__410 \
  ((wuffs_base__pixel_subsampling)0x212100)

static inline uint32_t wuffs_base__pixel_subsampling__bias_x(
    wuffs_base__pixel_subsampling s,
    uint32_t plane) {
  uint32_t shift = ((plane & 0x03) * 8) + 6;
  return (s >> shift) & 0x03;
}

static inline uint32_t wuffs_base__pixel_subsampling__shift_x(
    wuffs_base__pixel_subsampling s,
    uint32_t plane) {
  uint32_t shift = ((plane & 0x03) * 8) + 4;
  return (s >> shift) & 0x03;
}

static inline uint32_t wuffs_base__pixel_subsampling__bias_y(
    wuffs_base__pixel_subsampling s,
    uint32_t plane) {
  uint32_t shift = ((plane & 0x03) * 8) + 2;
  return (s >> shift) & 0x03;
}

static inline uint32_t wuffs_base__pixel_subsampling__shift_y(
    wuffs_base__pixel_subsampling s,
    uint32_t plane) {
  uint32_t shift = ((plane & 0x03) * 8) + 0;
  return (s >> shift) & 0x03;
}

// --------

typedef struct {
  // Do not access the private_impl's fields directly. There is no API/ABI
  // compatibility or safety guarantee if you do so.
  struct {
    wuffs_base__pixel_format pixfmt;
    wuffs_base__pixel_subsampling pixsub;
    uint32_t width;
    uint32_t height;
    uint32_t num_loops;
    bool first_frame_is_opaque;
  } private_impl;
} wuffs_base__image_config;

// TODO: Should this function return bool? An error type?
static inline void wuffs_base__image_config__initialize(
    wuffs_base__image_config* c,
    wuffs_base__pixel_format pixfmt,
    wuffs_base__pixel_subsampling pixsub,
    uint32_t width,
    uint32_t height,
    uint32_t num_loops,
    bool first_frame_is_opaque) {
  if (!c) {
    return;
  }
  if (pixfmt) {
    uint64_t wh = ((uint64_t)width) * ((uint64_t)height);
    // TODO: handle things other than 1 byte per pixel.
    if (wh <= ((uint64_t)SIZE_MAX)) {
      c->private_impl.pixfmt = pixfmt;
      c->private_impl.pixsub = pixsub;
      c->private_impl.width = width;
      c->private_impl.height = height;
      c->private_impl.num_loops = num_loops;
      c->private_impl.first_frame_is_opaque = first_frame_is_opaque;
      return;
    }
  }
  *c = ((wuffs_base__image_config){});
}

static inline void wuffs_base__image_config__invalidate(
    wuffs_base__image_config* c) {
  if (c) {
    *c = ((wuffs_base__image_config){});
  }
}

static inline bool wuffs_base__image_config__is_valid(
    wuffs_base__image_config* c) {
  return c && c->private_impl.pixfmt;
}

static inline wuffs_base__pixel_format wuffs_base__image_config__pixel_format(
    wuffs_base__image_config* c) {
  return c ? c->private_impl.pixfmt : 0;
}

static inline wuffs_base__pixel_subsampling
wuffs_base__image_config__pixel_subsampling(wuffs_base__image_config* c) {
  return c ? c->private_impl.pixsub : 0;
}

static inline wuffs_base__rect_ie_u32 wuffs_base__image_config__bounds(
    wuffs_base__image_config* c) {
  return c ? ((wuffs_base__rect_ie_u32){
                 .min_incl_x = 0,
                 .min_incl_y = 0,
                 .max_excl_x = c->private_impl.width,
                 .max_excl_y = c->private_impl.height,
             })
           : ((wuffs_base__rect_ie_u32){});
}

static inline uint32_t wuffs_base__image_config__width(
    wuffs_base__image_config* c) {
  return c ? c->private_impl.width : 0;
}

static inline uint32_t wuffs_base__image_config__height(
    wuffs_base__image_config* c) {
  return c ? c->private_impl.height : 0;
}

static inline uint32_t wuffs_base__image_config__num_loops(
    wuffs_base__image_config* c) {
  return c ? c->private_impl.num_loops : 0;
}

static inline uint32_t wuffs_base__image_config__first_frame_is_opaque(
    wuffs_base__image_config* c) {
  return c ? c->private_impl.first_frame_is_opaque : false;
}

// TODO: this is the right API for planar (not packed) pixbufs? Should it allow
// decoding into a color model different from the format's intrinsic one? For
// example, decoding a JPEG image straight to RGBA instead of to YCbCr?
static inline size_t wuffs_base__image_config__pixbuf_size(
    wuffs_base__image_config* c) {
  if (c) {
    uint64_t wh =
        ((uint64_t)c->private_impl.width) * ((uint64_t)c->private_impl.height);
    // TODO: handle things other than 1 byte per pixel.
    return (size_t)wh;
  }
  return 0;
}

// --------

// wuffs_base__animation_disposal encodes, for an animated image, how to
// dispose of a frame after displaying it:
//  - None means to draw the next frame on top of this one.
//  - Restore Background means to clear the frame's dirty rectangle to "the
//    background color" (in practice, this means transparent black) before
//    drawing the next frame.
//  - Restore Previous means to undo the current frame, so that the next frame
//    is drawn on top of the previous one.
typedef uint8_t wuffs_base__animation_disposal;

#define WUFFS_BASE__ANIMATION_DISPOSAL__NONE ((wuffs_base__animation_disposal)0)
#define WUFFS_BASE__ANIMATION_DISPOSAL__RESTORE_BACKGROUND \
  ((wuffs_base__animation_disposal)1)
#define WUFFS_BASE__ANIMATION_DISPOSAL__RESTORE_PREVIOUS \
  ((wuffs_base__animation_disposal)2)

// --------

typedef struct {
  // Do not access the private_impl's fields directly. There is no API/ABI
  // compatibility or safety guarantee if you do so.
  struct {
    wuffs_base__image_config config;
    uint32_t loop_count;  // 0-based count of the current loop.
    wuffs_base__pixel_buffer pixbuf;
    // TODO: color spaces.
    wuffs_base__rect_ie_u32 dirty_rect;
    wuffs_base__flicks duration;
    bool blend;
    wuffs_base__animation_disposal disposal;
    bool palette_changed;
    uint8_t palette[1024];
  } private_impl;
} wuffs_base__image_buffer;

static inline wuffs_base__status wuffs_base__image_buffer__set_from_pixbuf(
    wuffs_base__image_buffer* b,
    wuffs_base__image_config config,
    wuffs_base__pixel_buffer pixbuf) {
  if (!b) {
    return WUFFS_BASE__ERROR_BAD_RECEIVER;
  }
  *b = ((wuffs_base__image_buffer){});
  b->private_impl.config = config;
  b->private_impl.pixbuf = pixbuf;
  return WUFFS_BASE__STATUS_OK;
}

static inline wuffs_base__status wuffs_base__image_buffer__set_from_slice(
    wuffs_base__image_buffer* b,
    wuffs_base__image_config config,
    wuffs_base__slice_u8 pixbuf_memory) {
  if (!b) {
    return WUFFS_BASE__ERROR_BAD_RECEIVER;
  }
  *b = ((wuffs_base__image_buffer){});
  // TODO: don't assume 1 byte per pixel. Don't assume packed.
  uint64_t wh = ((uint64_t)config.private_impl.width) *
                ((uint64_t)config.private_impl.height);
  if (wh > pixbuf_memory.len) {
    return WUFFS_BASE__ERROR_BAD_ARGUMENT_LENGTH_TOO_SHORT;
  }
  b->private_impl.config = config;
  wuffs_base__table_u8* tab = &b->private_impl.pixbuf.planes[0];
  tab->ptr = pixbuf_memory.ptr;
  tab->width = config.private_impl.width;
  tab->height = config.private_impl.height;
  tab->stride = config.private_impl.width;
  return WUFFS_BASE__STATUS_OK;
}

// The palette argument is ignored unless its length is exactly 1024.
static inline void wuffs_base__image_buffer__update(
    wuffs_base__image_buffer* b,
    wuffs_base__rect_ie_u32 dirty_rect,
    wuffs_base__flicks duration,
    bool blend,
    wuffs_base__animation_disposal disposal,
    wuffs_base__slice_u8 palette) {
  if (!b) {
    return;
  }

  // Clip the dirty_rect to the image bounds.
  dirty_rect.max_excl_x = wuffs_base__u32__min(
      dirty_rect.max_excl_x, b->private_impl.config.private_impl.width);
  dirty_rect.max_excl_y = wuffs_base__u32__min(
      dirty_rect.max_excl_y, b->private_impl.config.private_impl.height);
  b->private_impl.dirty_rect = dirty_rect;

  b->private_impl.duration = duration;
  b->private_impl.blend = blend;
  b->private_impl.disposal = disposal;
  b->private_impl.palette_changed = palette.ptr && (palette.len == 1024);
  if (b->private_impl.palette_changed) {
    memmove(b->private_impl.palette, palette.ptr, 1024);
  }
}

// wuffs_base__image_buffer__loop returns whether the image decoder should loop
// back to the beginning of the animation, assuming that we've reached the end
// of the encoded stream. If so, it increments b's count of the animation loops
// played so far.
static inline bool wuffs_base__image_buffer__loop(wuffs_base__image_buffer* b) {
  if (!b) {
    return false;
  }
  uint32_t n = b->private_impl.config.private_impl.num_loops;
  if (n == 0) {
    return true;
  }
  if (b->private_impl.loop_count < n - 1) {
    b->private_impl.loop_count++;
    return true;
  }
  return false;
}

// wuffs_base__image_config returns the overall configuration for this frame.
static inline wuffs_base__image_config* wuffs_base__image_buffer__image_config(
    wuffs_base__image_buffer* b) {
  return b ? &b->private_impl.config : NULL;
}

// wuffs_base__image_buffer__dirty_rect returns an upper bound for what part of
// this frame's pixels differs from the previous frame.
static inline wuffs_base__rect_ie_u32 wuffs_base__image_buffer__dirty_rect(
    wuffs_base__image_buffer* b) {
  return b ? b->private_impl.dirty_rect : ((wuffs_base__rect_ie_u32){});
}

// wuffs_base__image_buffer__duration returns the amount of time to display
// this frame. Zero means to display forever - a still (non-animated) image.
static inline wuffs_base__flicks wuffs_base__image_buffer__duration(
    wuffs_base__image_buffer* b) {
  return b ? b->private_impl.duration : 0;
}

// wuffs_base__image_buffer__blend returns, for a transparent image, whether to
// blend this frame with the existing canvas.
//
// In Porter-Duff compositing operator terminology, false means "src" and true
// means "src over dst".
static inline bool wuffs_base__image_buffer__blend(
    wuffs_base__image_buffer* b) {
  return b && b->private_impl.blend;
}

// wuffs_base__image_buffer__disposal returns, for an animated image, how to
// dispose of this frame after displaying it.
static inline wuffs_base__animation_disposal wuffs_base__image_buffer__disposal(
    wuffs_base__image_buffer* b) {
  return b ? b->private_impl.disposal : 0;
}

// wuffs_base__image_buffer__palette_changed returns whether this frame's
// palette differs from the previous frame. It is conservative and may return
// false positives (but never false negatives).
static inline bool wuffs_base__image_buffer__palette_changed(
    wuffs_base__image_buffer* b) {
  return b && b->private_impl.palette_changed;
}

// wuffs_base__image_buffer__palette returns the palette that the pixel data
// can index. The backing array is inside b and has length 1024.
static inline wuffs_base__slice_u8 wuffs_base__image_buffer__palette(
    wuffs_base__image_buffer* b) {
  return b ? ((wuffs_base__slice_u8){.ptr = b->private_impl.palette,
                                     .len = 1024})
           : ((wuffs_base__slice_u8){});
}

static inline wuffs_base__table_u8 wuffs_base__image_buffer__plane(
    wuffs_base__image_buffer* b,
    uint32_t p) {
  return (b && (p < WUFFS_BASE__PIXEL_FORMAT__NUM_PLANES_MAX))
             ? b->private_impl.pixbuf.planes[p]
             : ((wuffs_base__table_u8){});
}

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // WUFFS_INCLUDE_GUARD__BASE_PUBLIC

// ---------------- Use Declarations

#ifdef __cplusplus
extern "C" {
#endif

// ---------------- Status Codes

#define wuffs_adler32__packageid 681002  // 0x000A642A

const char* wuffs_adler32__status__string(wuffs_base__status s);

// ---------------- Public Consts

// ---------------- Structs

typedef struct {
  // Do not access the private_impl's fields directly. There is no API/ABI
  // compatibility or safety guarantee if you do so. Instead, use the
  // wuffs_adler32__hasher__etc functions.
  //
  // In C++, these fields would be "private", but C does not support that.
  //
  // It is a struct, not a struct*, so that it can be stack allocated.
  struct {
    wuffs_base__status status;
    uint32_t magic;

    uint32_t f_state;
    bool f_started;

  } private_impl;
} wuffs_adler32__hasher;

// ---------------- Public Initializer Prototypes

// wuffs_adler32__hasher__check_wuffs_version is an initializer function.
//
// It should be called before any other wuffs_adler32__hasher__* function.
//
// Pass sizeof(*self) and WUFFS_VERSION for sizeof_star_self and wuffs_version.
void wuffs_adler32__hasher__check_wuffs_version(wuffs_adler32__hasher* self,
                                                size_t sizeof_star_self,
                                                uint64_t wuffs_version);

// ---------------- Public Function Prototypes

uint32_t wuffs_adler32__hasher__update(wuffs_adler32__hasher* self,
                                       wuffs_base__slice_u8 a_x);

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // WUFFS_INCLUDE_GUARD__ADLER32