Implement PNG decompression

This patch adds PNG decompression for images without interlacing and
without alpha channel.

Only basic image data is supported. Background, transparency, gamma,
paletted images are not supported.

1 files changed, 0 insertions, 53 deletions

diff --git a/lisiblepng/src/bitstream.c b/lisiblepng/src/bitstream.c
deleted file mode 100644
index e7ddb79..0000000
--- a/lisiblepng/src/bitstream.c
+++ /dev/null
@@ -1,53 +0,0 @@
-#include "bitstream.h"
-#include "assert.h"
-
-#define MAX(x, y) (((x) > (y)) ? (x) : (y))
-#define MIN(x, y) (((x) < (y)) ? (x) : (y))
-
-void Bitstream_init(Bitstream *bitstream, const uint8_t *data,
-                    size_t data_size) {
-  ASSERT(bitstream != NULL);
-  ASSERT(data != NULL);
-  bitstream->data = data;
-  bitstream->data_size = data_size;
-  bitstream->current_byte_index = 0;
-  bitstream->current_bit_offset = 0;
-}
-
-void bitstream_advance(Bitstream *bitstream, size_t bit_count) {
-  ASSERT(bitstream != NULL);
-  uint8_t current_bit = bitstream->current_bit_offset;
-  bitstream->current_byte_index =
-      bitstream->current_byte_index + (current_bit + bit_count) / 8;
-  bitstream->current_bit_offset = (current_bit + bit_count) % 8;
-}
-
-void Bitstream_skip(Bitstream *bitstream, size_t bit_count) {
-  ASSERT(bitstream != NULL);
-  bitstream_advance(bitstream, bit_count);
-}
-
-uint16_t Bitstream_next_bits(Bitstream *bitstream, int bit_count) {
-  ASSERT(bitstream != NULL);
-  ASSERT(bit_count <= 16);
-  ASSERT((bitstream->current_bit_offset + (size_t)bit_count) / 8 <=
-         bitstream->data_size);
-
-  int bit_to_read = bit_count;
-  uint16_t val = bitstream->data[bitstream->current_byte_index] >>
-                 bitstream->current_bit_offset;
-
-  size_t bit_read = MIN(bit_count, 8 - bitstream->current_bit_offset);
-  bitstream_advance(bitstream, bit_read);
-  bit_to_read -= bit_read;
-  while (bit_to_read > 0) {
-    val |= (bitstream->data[bitstream->current_byte_index] >>
-            bitstream->current_bit_offset)
-           << bit_read;
-    bit_read = MIN(bit_to_read, 8 - bitstream->current_bit_offset);
-    bitstream_advance(bitstream, bit_read);
-    bit_to_read -= bit_read;
-  }
-
-  return (val & ((1 << bit_count) - 1));
-}