Initial commit

5 files changed, 563 insertions, 0 deletions

diff --git a/Marlin/src/libs/heatshrink/LICENSE b/Marlin/src/libs/heatshrink/LICENSE
new file mode 100644
index 0000000..a40fc72
--- /dev/null
+++ b/Marlin/src/libs/heatshrink/LICENSE
@@ -0,0 +1,14 @@
+Copyright (c) 2013-2015, Scott Vokes <vokes.s@gmail.com>
+All rights reserved.
+
+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.
+
+THE 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.
diff --git a/Marlin/src/libs/heatshrink/heatshrink_common.h b/Marlin/src/libs/heatshrink/heatshrink_common.h
new file mode 100644
index 0000000..68653e4
--- /dev/null
+++ b/Marlin/src/libs/heatshrink/heatshrink_common.h
@@ -0,0 +1,20 @@
+/**
+ * libs/heatshrink/heatshrink_common.h
+ */
+#pragma once
+
+#define HEATSHRINK_AUTHOR "Scott Vokes <vokes.s@gmail.com>"
+#define HEATSHRINK_URL "github.com/atomicobject/heatshrink"
+
+/* Version 0.4.1 */
+#define HEATSHRINK_VERSION_MAJOR 0
+#define HEATSHRINK_VERSION_MINOR 4
+#define HEATSHRINK_VERSION_PATCH 1
+
+#define HEATSHRINK_MIN_WINDOW_BITS 4
+#define HEATSHRINK_MAX_WINDOW_BITS 15
+
+#define HEATSHRINK_MIN_LOOKAHEAD_BITS 3
+
+#define HEATSHRINK_LITERAL_MARKER 0x01
+#define HEATSHRINK_BACKREF_MARKER 0x00
diff --git a/Marlin/src/libs/heatshrink/heatshrink_config.h b/Marlin/src/libs/heatshrink/heatshrink_config.h
new file mode 100644
index 0000000..90520f1
--- /dev/null
+++ b/Marlin/src/libs/heatshrink/heatshrink_config.h
@@ -0,0 +1,26 @@
+/**
+ * libs/heatshrink/heatshrink_config.h
+ */
+#pragma once
+
+// Should functionality assuming dynamic allocation be used?
+#ifndef HEATSHRINK_DYNAMIC_ALLOC
+  //#define HEATSHRINK_DYNAMIC_ALLOC 1
+#endif
+
+#if HEATSHRINK_DYNAMIC_ALLOC
+  // Optional replacement of malloc/free
+  #define HEATSHRINK_MALLOC(SZ) malloc(SZ)
+  #define HEATSHRINK_FREE(P, SZ) free(P)
+#else
+  // Required parameters for static configuration
+  #define HEATSHRINK_STATIC_INPUT_BUFFER_SIZE 32
+  #define HEATSHRINK_STATIC_WINDOW_BITS 8
+  #define HEATSHRINK_STATIC_LOOKAHEAD_BITS 4
+#endif
+
+// Turn on logging for debugging
+#define HEATSHRINK_DEBUGGING_LOGS 0
+
+// Use indexing for faster compression. (This requires additional space.)
+#define HEATSHRINK_USE_INDEX 1
diff --git a/Marlin/src/libs/heatshrink/heatshrink_decoder.cpp b/Marlin/src/libs/heatshrink/heatshrink_decoder.cpp
new file mode 100644
index 0000000..073a7ed
--- /dev/null
+++ b/Marlin/src/libs/heatshrink/heatshrink_decoder.cpp
@@ -0,0 +1,384 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../../inc/MarlinConfigPre.h"
+
+#if ENABLED(BINARY_FILE_TRANSFER)
+
+/**
+ * libs/heatshrink/heatshrink_decoder.cpp
+ */
+#include "heatshrink_decoder.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#pragma GCC optimize ("O3")
+
+/* States for the polling state machine. */
+typedef enum {
+  HSDS_TAG_BIT,               /* tag bit */
+  HSDS_YIELD_LITERAL,         /* ready to yield literal byte */
+  HSDS_BACKREF_INDEX_MSB,     /* most significant byte of index */
+  HSDS_BACKREF_INDEX_LSB,     /* least significant byte of index */
+  HSDS_BACKREF_COUNT_MSB,     /* most significant byte of count */
+  HSDS_BACKREF_COUNT_LSB,     /* least significant byte of count */
+  HSDS_YIELD_BACKREF          /* ready to yield back-reference */
+} HSD_state;
+
+#if HEATSHRINK_DEBUGGING_LOGS
+  #include <stdio.h>
+  #include <ctype.h>
+  #include <assert.h>
+  #define LOG(...) fprintf(stderr, __VA_ARGS__)
+  #define ASSERT(X) assert(X)
+  static const char *state_names[] = {
+    "tag_bit",
+    "yield_literal",
+    "backref_index_msb",
+    "backref_index_lsb",
+    "backref_count_msb",
+    "backref_count_lsb",
+    "yield_backref"
+  };
+#else
+  #define LOG(...) /* no-op */
+  #define ASSERT(X) /* no-op */
+#endif
+
+typedef struct {
+  uint8_t *buf;               /* output buffer */
+  size_t buf_size;            /* buffer size */
+  size_t *output_size;        /* bytes pushed to buffer, so far */
+} output_info;
+
+#define NO_BITS ((uint16_t)-1)
+
+/* Forward references. */
+static uint16_t get_bits(heatshrink_decoder *hsd, uint8_t count);
+static void push_byte(heatshrink_decoder *hsd, output_info *oi, uint8_t byte);
+
+#if HEATSHRINK_DYNAMIC_ALLOC
+heatshrink_decoder *heatshrink_decoder_alloc(uint16_t input_buffer_size, uint8_t window_sz2, uint8_t lookahead_sz2) {
+  if ((window_sz2 < HEATSHRINK_MIN_WINDOW_BITS) ||
+      (window_sz2 > HEATSHRINK_MAX_WINDOW_BITS) ||
+      (input_buffer_size == 0) ||
+      (lookahead_sz2 < HEATSHRINK_MIN_LOOKAHEAD_BITS) ||
+      (lookahead_sz2 >= window_sz2)) {
+      return nullptr;
+  }
+  size_t buffers_sz = (1 << window_sz2) + input_buffer_size;
+  size_t sz = sizeof(heatshrink_decoder) + buffers_sz;
+  heatshrink_decoder *hsd = HEATSHRINK_MALLOC(sz);
+  if (!hsd) return nullptr;
+  hsd->input_buffer_size = input_buffer_size;
+  hsd->window_sz2 = window_sz2;
+  hsd->lookahead_sz2 = lookahead_sz2;
+  heatshrink_decoder_reset(hsd);
+  LOG("-- allocated decoder with buffer size of %zu (%zu + %u + %u)\n",
+      sz, sizeof(heatshrink_decoder), (1 << window_sz2), input_buffer_size);
+  return hsd;
+}
+
+void heatshrink_decoder_free(heatshrink_decoder *hsd) {
+  size_t buffers_sz = (1 << hsd->window_sz2) + hsd->input_buffer_size;
+  size_t sz = sizeof(heatshrink_decoder) + buffers_sz;
+  HEATSHRINK_FREE(hsd, sz);
+  (void)sz;   /* may not be used by free */
+}
+#endif
+
+void heatshrink_decoder_reset(heatshrink_decoder *hsd) {
+  size_t buf_sz = 1 << HEATSHRINK_DECODER_WINDOW_BITS(hsd);
+  size_t input_sz = HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(hsd);
+  memset(hsd->buffers, 0, buf_sz + input_sz);
+  hsd->state = HSDS_TAG_BIT;
+  hsd->input_size = 0;
+  hsd->input_index = 0;
+  hsd->bit_index = 0x00;
+  hsd->current_byte = 0x00;
+  hsd->output_count = 0;
+  hsd->output_index = 0;
+  hsd->head_index = 0;
+}
+
+/* Copy SIZE bytes into the decoder's input buffer, if it will fit. */
+HSD_sink_res heatshrink_decoder_sink(heatshrink_decoder *hsd,
+  uint8_t *in_buf, size_t size, size_t *input_size) {
+  if (!hsd || !in_buf || !input_size)
+    return HSDR_SINK_ERROR_NULL;
+
+  size_t rem = HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(hsd) - hsd->input_size;
+  if (rem == 0) {
+    *input_size = 0;
+    return HSDR_SINK_FULL;
+  }
+
+  size = rem < size ? rem : size;
+  LOG("-- sinking %zd bytes\n", size);
+  /* copy into input buffer (at head of buffers) */
+  memcpy(&hsd->buffers[hsd->input_size], in_buf, size);
+  hsd->input_size += size;
+  *input_size = size;
+  return HSDR_SINK_OK;
+}
+
+
+/*****************
+ * Decompression *
+ *****************/
+
+#define BACKREF_COUNT_BITS(HSD) (HEATSHRINK_DECODER_LOOKAHEAD_BITS(HSD))
+#define BACKREF_INDEX_BITS(HSD) (HEATSHRINK_DECODER_WINDOW_BITS(HSD))
+
+// States
+static HSD_state st_tag_bit(heatshrink_decoder *hsd);
+static HSD_state st_yield_literal(heatshrink_decoder *hsd, output_info *oi);
+static HSD_state st_backref_index_msb(heatshrink_decoder *hsd);
+static HSD_state st_backref_index_lsb(heatshrink_decoder *hsd);
+static HSD_state st_backref_count_msb(heatshrink_decoder *hsd);
+static HSD_state st_backref_count_lsb(heatshrink_decoder *hsd);
+static HSD_state st_yield_backref(heatshrink_decoder *hsd, output_info *oi);
+
+HSD_poll_res heatshrink_decoder_poll(heatshrink_decoder *hsd, uint8_t *out_buf, size_t out_buf_size, size_t *output_size) {
+  if (!hsd || !out_buf || !output_size)
+    return HSDR_POLL_ERROR_NULL;
+
+  *output_size = 0;
+
+  output_info oi;
+  oi.buf = out_buf;
+  oi.buf_size = out_buf_size;
+  oi.output_size = output_size;
+
+  while (1) {
+    LOG("-- poll, state is %d (%s), input_size %d\n", hsd->state, state_names[hsd->state], hsd->input_size);
+    uint8_t in_state = hsd->state;
+    switch (in_state) {
+      case HSDS_TAG_BIT:
+        hsd->state = st_tag_bit(hsd);
+        break;
+      case HSDS_YIELD_LITERAL:
+        hsd->state = st_yield_literal(hsd, &oi);
+        break;
+      case HSDS_BACKREF_INDEX_MSB:
+        hsd->state = st_backref_index_msb(hsd);
+        break;
+      case HSDS_BACKREF_INDEX_LSB:
+        hsd->state = st_backref_index_lsb(hsd);
+        break;
+      case HSDS_BACKREF_COUNT_MSB:
+        hsd->state = st_backref_count_msb(hsd);
+        break;
+      case HSDS_BACKREF_COUNT_LSB:
+        hsd->state = st_backref_count_lsb(hsd);
+        break;
+      case HSDS_YIELD_BACKREF:
+        hsd->state = st_yield_backref(hsd, &oi);
+        break;
+      default:
+        return HSDR_POLL_ERROR_UNKNOWN;
+    }
+
+    // If the current state cannot advance, check if input or output
+    // buffer are exhausted.
+    if (hsd->state == in_state)
+      return (*output_size == out_buf_size) ? HSDR_POLL_MORE : HSDR_POLL_EMPTY;
+  }
+}
+
+static HSD_state st_tag_bit(heatshrink_decoder *hsd) {
+  uint32_t bits = get_bits(hsd, 1);  // get tag bit
+  if (bits == NO_BITS)
+    return HSDS_TAG_BIT;
+  else if (bits)
+    return HSDS_YIELD_LITERAL;
+  else if (HEATSHRINK_DECODER_WINDOW_BITS(hsd) > 8)
+    return HSDS_BACKREF_INDEX_MSB;
+  else {
+    hsd->output_index = 0;
+    return HSDS_BACKREF_INDEX_LSB;
+  }
+}
+
+static HSD_state st_yield_literal(heatshrink_decoder *hsd, output_info *oi) {
+  /* Emit a repeated section from the window buffer, and add it (again)
+   * to the window buffer. (Note that the repetition can include
+   * itself.)*/
+  if (*oi->output_size < oi->buf_size) {
+    uint16_t byte = get_bits(hsd, 8);
+    if (byte == NO_BITS) { return HSDS_YIELD_LITERAL; } /* out of input */
+    uint8_t *buf = &hsd->buffers[HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(hsd)];
+    uint16_t mask = (1 << HEATSHRINK_DECODER_WINDOW_BITS(hsd))  - 1;
+    uint8_t c = byte & 0xFF;
+    LOG("-- emitting literal byte 0x%02x ('%c')\n", c, isprint(c) ? c : '.');
+    buf[hsd->head_index++ & mask] = c;
+    push_byte(hsd, oi, c);
+    return HSDS_TAG_BIT;
+  }
+  return HSDS_YIELD_LITERAL;
+}
+
+static HSD_state st_backref_index_msb(heatshrink_decoder *hsd) {
+  uint8_t bit_ct = BACKREF_INDEX_BITS(hsd);
+  ASSERT(bit_ct > 8);
+  uint16_t bits = get_bits(hsd, bit_ct - 8);
+  LOG("-- backref index (msb), got 0x%04x (+1)\n", bits);
+  if (bits == NO_BITS) { return HSDS_BACKREF_INDEX_MSB; }
+  hsd->output_index = bits << 8;
+  return HSDS_BACKREF_INDEX_LSB;
+}
+
+static HSD_state st_backref_index_lsb(heatshrink_decoder *hsd) {
+  uint8_t bit_ct = BACKREF_INDEX_BITS(hsd);
+  uint16_t bits = get_bits(hsd, bit_ct < 8 ? bit_ct : 8);
+  LOG("-- backref index (lsb), got 0x%04x (+1)\n", bits);
+  if (bits == NO_BITS) { return HSDS_BACKREF_INDEX_LSB; }
+  hsd->output_index |= bits;
+  hsd->output_index++;
+  uint8_t br_bit_ct = BACKREF_COUNT_BITS(hsd);
+  hsd->output_count = 0;
+  return (br_bit_ct > 8) ? HSDS_BACKREF_COUNT_MSB : HSDS_BACKREF_COUNT_LSB;
+}
+
+static HSD_state st_backref_count_msb(heatshrink_decoder *hsd) {
+  uint8_t br_bit_ct = BACKREF_COUNT_BITS(hsd);
+  ASSERT(br_bit_ct > 8);
+  uint16_t bits = get_bits(hsd, br_bit_ct - 8);
+  LOG("-- backref count (msb), got 0x%04x (+1)\n", bits);
+  if (bits == NO_BITS) { return HSDS_BACKREF_COUNT_MSB; }
+  hsd->output_count = bits << 8;
+  return HSDS_BACKREF_COUNT_LSB;
+}
+
+static HSD_state st_backref_count_lsb(heatshrink_decoder *hsd) {
+  uint8_t br_bit_ct = BACKREF_COUNT_BITS(hsd);
+  uint16_t bits = get_bits(hsd, br_bit_ct < 8 ? br_bit_ct : 8);
+  LOG("-- backref count (lsb), got 0x%04x (+1)\n", bits);
+  if (bits == NO_BITS) { return HSDS_BACKREF_COUNT_LSB; }
+  hsd->output_count |= bits;
+  hsd->output_count++;
+  return HSDS_YIELD_BACKREF;
+}
+
+static HSD_state st_yield_backref(heatshrink_decoder *hsd, output_info *oi) {
+  size_t count = oi->buf_size - *oi->output_size;
+  if (count > 0) {
+    size_t i = 0;
+    if (hsd->output_count < count) count = hsd->output_count;
+    uint8_t *buf = &hsd->buffers[HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(hsd)];
+    uint16_t mask = (1 << HEATSHRINK_DECODER_WINDOW_BITS(hsd)) - 1;
+    uint16_t neg_offset = hsd->output_index;
+    LOG("-- emitting %zu bytes from -%u bytes back\n", count, neg_offset);
+    ASSERT(neg_offset <= mask + 1);
+    ASSERT(count <= (size_t)(1 << BACKREF_COUNT_BITS(hsd)));
+
+    for (i = 0; i < count; i++) {
+      uint8_t c = buf[(hsd->head_index - neg_offset) & mask];
+      push_byte(hsd, oi, c);
+      buf[hsd->head_index & mask] = c;
+      hsd->head_index++;
+      LOG("  -- ++ 0x%02x\n", c);
+    }
+    hsd->output_count -= count;
+    if (hsd->output_count == 0) { return HSDS_TAG_BIT; }
+  }
+  return HSDS_YIELD_BACKREF;
+}
+
+/* Get the next COUNT bits from the input buffer, saving incremental progress.
+ * Returns NO_BITS on end of input, or if more than 15 bits are requested. */
+static uint16_t get_bits(heatshrink_decoder *hsd, uint8_t count) {
+  uint16_t accumulator = 0;
+  int i = 0;
+  if (count > 15) return NO_BITS;
+  LOG("-- popping %u bit(s)\n", count);
+
+  /* If we aren't able to get COUNT bits, suspend immediately, because we
+   * don't track how many bits of COUNT we've accumulated before suspend. */
+  if (hsd->input_size == 0 && hsd->bit_index < (1 << (count - 1))) return NO_BITS;
+
+  for (i = 0; i < count; i++) {
+    if (hsd->bit_index == 0x00) {
+      if (hsd->input_size == 0) {
+        LOG("  -- out of bits, suspending w/ accumulator of %u (0x%02x)\n", accumulator, accumulator);
+        return NO_BITS;
+      }
+      hsd->current_byte = hsd->buffers[hsd->input_index++];
+      LOG("  -- pulled byte 0x%02x\n", hsd->current_byte);
+      if (hsd->input_index == hsd->input_size) {
+        hsd->input_index = 0; /* input is exhausted */
+        hsd->input_size = 0;
+      }
+      hsd->bit_index = 0x80;
+    }
+    accumulator <<= 1;
+    if (hsd->current_byte & hsd->bit_index) {
+      accumulator |= 0x01;
+      if (0) {
+        LOG("  -- got 1, accumulator 0x%04x, bit_index 0x%02x\n",
+        accumulator, hsd->bit_index);
+      }
+    }
+    else if (0) {
+      LOG("  -- got 0, accumulator 0x%04x, bit_index 0x%02x\n",
+      accumulator, hsd->bit_index);
+    }
+    hsd->bit_index >>= 1;
+  }
+
+  if (count > 1) LOG("  -- accumulated %08x\n", accumulator);
+  return accumulator;
+}
+
+HSD_finish_res heatshrink_decoder_finish(heatshrink_decoder *hsd) {
+  if (!hsd) return HSDR_FINISH_ERROR_NULL;
+  switch (hsd->state) {
+    case HSDS_TAG_BIT:
+      return hsd->input_size == 0 ? HSDR_FINISH_DONE : HSDR_FINISH_MORE;
+
+    /* If we want to finish with no input, but are in these states, it's
+     * because the 0-bit padding to the last byte looks like a backref
+     * marker bit followed by all 0s for index and count bits. */
+    case HSDS_BACKREF_INDEX_LSB:
+    case HSDS_BACKREF_INDEX_MSB:
+    case HSDS_BACKREF_COUNT_LSB:
+    case HSDS_BACKREF_COUNT_MSB:
+      return hsd->input_size == 0 ? HSDR_FINISH_DONE : HSDR_FINISH_MORE;
+
+    /* If the output stream is padded with 0xFFs (possibly due to being in
+     * flash memory), also explicitly check the input size rather than
+     * uselessly returning MORE but yielding 0 bytes when polling. */
+    case HSDS_YIELD_LITERAL:
+      return hsd->input_size == 0 ? HSDR_FINISH_DONE : HSDR_FINISH_MORE;
+
+    default: return HSDR_FINISH_MORE;
+  }
+}
+
+static void push_byte(heatshrink_decoder *hsd, output_info *oi, uint8_t byte) {
+  LOG(" -- pushing byte: 0x%02x ('%c')\n", byte, isprint(byte) ? byte : '.');
+  oi->buf[(*oi->output_size)++] = byte;
+  (void)hsd;
+}
+
+#endif // BINARY_FILE_TRANSFER
diff --git a/Marlin/src/libs/heatshrink/heatshrink_decoder.h b/Marlin/src/libs/heatshrink/heatshrink_decoder.h
new file mode 100644
index 0000000..eb113aa
--- /dev/null
+++ b/Marlin/src/libs/heatshrink/heatshrink_decoder.h
@@ -0,0 +1,119 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+/**
+ * libs/heatshrink/heatshrink_decoder.h
+ */
+#pragma once
+
+#include "heatshrink_common.h"
+#include "heatshrink_config.h"
+
+#include <stdint.h>
+#include <stddef.h>
+
+typedef enum {
+  HSDR_SINK_OK,               /* data sunk, ready to poll */
+  HSDR_SINK_FULL,             /* out of space in internal buffer */
+  HSDR_SINK_ERROR_NULL=-1,    /* NULL argument */
+} HSD_sink_res;
+
+typedef enum {
+  HSDR_POLL_EMPTY,            /* input exhausted */
+  HSDR_POLL_MORE,             /* more data remaining, call again w/ fresh output buffer */
+  HSDR_POLL_ERROR_NULL=-1,    /* NULL arguments */
+  HSDR_POLL_ERROR_UNKNOWN=-2,
+} HSD_poll_res;
+
+typedef enum {
+  HSDR_FINISH_DONE,           /* output is done */
+  HSDR_FINISH_MORE,           /* more output remains */
+  HSDR_FINISH_ERROR_NULL=-1,  /* NULL arguments */
+} HSD_finish_res;
+
+#if HEATSHRINK_DYNAMIC_ALLOC
+#define HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(BUF) \
+  ((BUF)->input_buffer_size)
+#define HEATSHRINK_DECODER_WINDOW_BITS(BUF) \
+  ((BUF)->window_sz2)
+#define HEATSHRINK_DECODER_LOOKAHEAD_BITS(BUF) \
+  ((BUF)->lookahead_sz2)
+#else
+#define HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(_) \
+  HEATSHRINK_STATIC_INPUT_BUFFER_SIZE
+#define HEATSHRINK_DECODER_WINDOW_BITS(_) \
+  (HEATSHRINK_STATIC_WINDOW_BITS)
+#define HEATSHRINK_DECODER_LOOKAHEAD_BITS(BUF) \
+  (HEATSHRINK_STATIC_LOOKAHEAD_BITS)
+#endif
+
+typedef struct {
+  uint16_t input_size;        /* bytes in input buffer */
+  uint16_t input_index;       /* offset to next unprocessed input byte */
+  uint16_t output_count;      /* how many bytes to output */
+  uint16_t output_index;      /* index for bytes to output */
+  uint16_t head_index;        /* head of window buffer */
+  uint8_t state;              /* current state machine node */
+  uint8_t current_byte;       /* current byte of input */
+  uint8_t bit_index;          /* current bit index */
+
+#if HEATSHRINK_DYNAMIC_ALLOC
+  /* Fields that are only used if dynamically allocated. */
+  uint8_t window_sz2;         /* window buffer bits */
+  uint8_t lookahead_sz2;      /* lookahead bits */
+  uint16_t input_buffer_size; /* input buffer size */
+
+  /* Input buffer, then expansion window buffer */
+  uint8_t buffers[];
+#else
+  /* Input buffer, then expansion window buffer */
+  uint8_t buffers[(1 << HEATSHRINK_DECODER_WINDOW_BITS(_)) + HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(_)];
+#endif
+} heatshrink_decoder;
+
+#if HEATSHRINK_DYNAMIC_ALLOC
+/* Allocate a decoder with an input buffer of INPUT_BUFFER_SIZE bytes,
+ * an expansion buffer size of 2^WINDOW_SZ2, and a lookahead
+ * size of 2^lookahead_sz2. (The window buffer and lookahead sizes
+ * must match the settings used when the data was compressed.)
+ * Returns NULL on error. */
+heatshrink_decoder *heatshrink_decoder_alloc(uint16_t input_buffer_size, uint8_t expansion_buffer_sz2, uint8_t lookahead_sz2);
+
+/* Free a decoder. */
+void heatshrink_decoder_free(heatshrink_decoder *hsd);
+#endif
+
+/* Reset a decoder. */
+void heatshrink_decoder_reset(heatshrink_decoder *hsd);
+
+/* Sink at most SIZE bytes from IN_BUF into the decoder. *INPUT_SIZE is set to
+ * indicate how many bytes were actually sunk (in case a buffer was filled). */
+HSD_sink_res heatshrink_decoder_sink(heatshrink_decoder *hsd, uint8_t *in_buf, size_t size, size_t *input_size);
+
+/* Poll for output from the decoder, copying at most OUT_BUF_SIZE bytes into
+ * OUT_BUF (setting *OUTPUT_SIZE to the actual amount copied). */
+HSD_poll_res heatshrink_decoder_poll(heatshrink_decoder *hsd, uint8_t *out_buf, size_t out_buf_size, size_t *output_size);
+
+/* Notify the dencoder that the input stream is finished.
+ * If the return value is HSDR_FINISH_MORE, there is still more output, so
+ * call heatshrink_decoder_poll and repeat. */
+HSD_finish_res heatshrink_decoder_finish(heatshrink_decoder *hsd);