Zlib and Gzip support

9 files changed, 509 insertions, 284 deletions

diff --git a/README b/README
index 363ed99..d75856f 100644
--- a/README
+++ b/README
@@ -1,17 +1,20 @@
 Zopfli Compression Algorithm is a compression library programmed in C to perform
 very good, but slow, deflate or zlib compression.
 
-gzip.c is separate from the library and contains an example program to create
+zopfli.c is separate from the library and contains an example program to create
 very well compressed gzip files.
 
-The basic function to compress data is Deflate in deflate.h. Use the Options
+The basic functions to compress data are Deflate in deflate.h, ZlibCompress in
+zlib_container.h and GzipCompress in gzip_container.h. Use the Options
 object to set parameters that affect the speed and compression. Use the
 InitOptions function to place the default values in the Options first.
 
-This function creates a valid deflate stream. To get a valid zlib stream
-instead, you need to add a small zlib header and a checksum around this stream
-yourself. Please see the Zlib specification for more details:
-http://www.ietf.org/rfc/rfc1950.txt.
+Deflate creates a valid deflate stream in memory, see:
+http://www.ietf.org/rfc/rfc1951.txt
+ZlibCompress creates a valid zlib stream in memory, see:
+http://www.ietf.org/rfc/rfc1950.txt
+GzipCompress creates a valid gzip stream in memory, see:
+http://www.ietf.org/rfc/rfc1952.txt
 
 This library can only compress, not decompress. Existing zlib or deflate
 libraries can decompress the data.
diff --git a/blocksplitter.c b/blocksplitter.c
index c54ef77..157273e 100644
--- a/blocksplitter.c
+++ b/blocksplitter.c
@@ -223,13 +223,13 @@ void BlockSplitLZ77(const Options* options,
   size_t i;
   size_t llpos = 0;
   size_t numblocks = 1;
-  unsigned char* done = (unsigned char*)malloc(llsize);
+  unsigned char* done;
   double splitcost, origcost;
 
-  if (!done) exit(-1); /* Allocation failed. */
-
   if (llsize < 10) return;  /* This code fails on tiny files. */
 
+  done = (unsigned char*)malloc(llsize);
+  if (!done) exit(-1); /* Allocation failed. */
   for (i = 0; i < llsize; i++) done[i] = 0;
 
   lstart = 0;
diff --git a/gzip.c b/gzip.c
deleted file mode 100644
index ca5bf69..0000000
--- a/gzip.c
+++ /dev/null
@@ -1,271 +0,0 @@
-/*
-Copyright 2011 Google Inc. All Rights Reserved.
-
-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
-
-    http://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.
-
-Author: lode.vandevenne@gmail.com (Lode Vandevenne)
-Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
-*/
-
-/*
-Example program using the zopfli compression algorithm library. It is a tool
-which behaves like a subset of gzip which can only compress, not decompress.
-*/
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "deflate.h"
-#include "util.h"
-
-/*
-Loads a file into a memory array.
-*/
-static void LoadFile(const char* filename,
-                     unsigned char** out, size_t* outsize) {
-  FILE* file;
-
-  *out = 0;
-  *outsize = 0;
-  file = fopen(filename, "rb");
-  if (!file) return;
-
-  fseek(file , 0 , SEEK_END);
-  *outsize = ftell(file);
-  rewind(file);
-
-  *out = (unsigned char*)malloc(*outsize);
-
-  if (*outsize && (*out)) {
-    size_t testsize = fread(*out, 1, *outsize, file);
-    if (testsize != *outsize) {
-      /* It could be a directory */
-      free(*out);
-      *out = 0;
-      *outsize = 0;
-    }
-  }
-
-  assert(!(*outsize) || out);  /* If size is not zero, out must be allocated. */
-  fclose(file);
-}
-
-/*
-Saves a file from a memory array, overwriting the file if it existed.
-*/
-static void SaveFile(const char* filename,
-                     const unsigned char* in, size_t insize) {
-  FILE* file = fopen(filename, "wb" );
-  assert(file);
-  fwrite((char*)in, 1, insize, file);
-  fclose(file);
-}
-
-/* Table of CRCs of all 8-bit messages. */
-static unsigned long crc_table[256];
-
-/* Flag: has the table been computed? Initially false. */
-static int crc_table_computed = 0;
-
-/* Makes the table for a fast CRC. */
-void MakeCRCTable() {
-  unsigned long c;
-  int n, k;
-  for (n = 0; n < 256; n++) {
-    c = (unsigned long) n;
-    for (k = 0; k < 8; k++) {
-      if (c & 1) {
-        c = 0xedb88320L ^ (c >> 1);
-      } else {
-        c = c >> 1;
-      }
-    }
-    crc_table[n] = c;
-  }
-  crc_table_computed = 1;
-}
-
-/*
-Updates a running crc with the bytes buf[0..len-1] and returns
-the updated crc. The crc should be initialized to zero.
-*/
-unsigned long UpdateCRC(unsigned long crc,
-                        const unsigned char *buf, size_t len) {
-  unsigned long c = crc ^ 0xffffffffL;
-  unsigned n;
-
-  if (!crc_table_computed)
-    MakeCRCTable();
-  for (n = 0; n < len; n++) {
-    c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
-  }
-  return c ^ 0xffffffffL;
-}
-
-/* Returns the CRC of the bytes buf[0..len-1]. */
-unsigned long CRC(const unsigned char* buf, int len) {
-  return UpdateCRC(0L, buf, len);
-}
-
-/*
-Compresses the data according to the gzip specification.
-*/
-void Gzip(const Options* options,
-          const unsigned char* in, size_t insize,
-          unsigned char** out, size_t* outsize) {
-  unsigned long crcvalue = CRC(in, insize);
-  unsigned char bp = 0;
-
-  APPEND_DATA(31, out, outsize);  /* ID1 */
-  APPEND_DATA(139, out, outsize);  /* ID2 */
-  APPEND_DATA(8, out, outsize);  /* CM */
-  APPEND_DATA(0, out, outsize);  /* FLG */
-  /* MTIME */
-  APPEND_DATA(0, out, outsize);
-  APPEND_DATA(0, out, outsize);
-  APPEND_DATA(0, out, outsize);
-  APPEND_DATA(0, out, outsize);
-
-  APPEND_DATA(2, out, outsize);  /* XFL, 2 indicates best compression. */
-  APPEND_DATA(3, out, outsize);  /* OS follows Unix conventions. */
-
-  Deflate(options, 2 /* Dynamic block */, 1, in, insize, &bp, out, outsize);
-
-  /* CRC */
-  APPEND_DATA(crcvalue % 256, out, outsize);
-  APPEND_DATA((crcvalue >> 8) % 256, out, outsize);
-  APPEND_DATA((crcvalue >> 16) % 256, out, outsize);
-  APPEND_DATA((crcvalue >> 24) % 256, out, outsize);
-
-  /* ISIZE */
-  APPEND_DATA(insize % 256, out, outsize);
-  APPEND_DATA((insize >> 8) % 256, out, outsize);
-  APPEND_DATA((insize >> 16) % 256, out, outsize);
-  APPEND_DATA((insize >> 24) % 256, out, outsize);
-
-  if (options->verbose) {
-    fprintf(stderr,
-            "Original Size: %d, Compressed: %d, Compression: %f%% Removed\n",
-            (int)insize, (int)*outsize,
-            100.0f * (float)(insize - *outsize) / (float)insize);
-  }
-}
-
-/*
-outfilename: filename to write output to, or 0 to write to stdout instead
-*/
-void GzipFile(const Options* options,
-              const char* infilename,
-              const char* outfilename) {
-  unsigned char* in;
-  size_t insize;
-  unsigned char* out = 0;
-  size_t outsize = 0;
-  LoadFile(infilename, &in, &insize);
-  if (insize == 0) {
-    fprintf(stderr, "Invalid filename: %s\n", infilename);
-    return;
-  }
-  Gzip(options, in, insize, &out, &outsize);
-  if (outfilename) {
-    SaveFile(outfilename, out, outsize);
-  } else {
-    size_t i;
-    for (i = 0; i < outsize; i++) {
-      /* Works only if terminal does not convert newlines. */
-      printf("%c", out[i]);
-    }
-  }
-
-  free(out);
-  free(in);
-}
-
-/*
-Add two strings together. Size does not matter. Result must be freed.
-*/
-static char* AddStrings(const char* str1, const char* str2) {
-  size_t len = strlen(str1) + strlen(str2);
-  char* result = (char*)malloc(len + 1);
-  if (!result) exit(-1); /* Allocation failed. */
-  strcpy(result, str1);
-  strcat(result, str2);
-  return result;
-}
-
-static char StringsEqual(const char* str1, const char* str2) {
-  return strcmp(str1, str2) == 0;
-}
-
-int main(int argc, char* argv[]) {
-  Options options;
-  const char* filename = 0;
-  int output_to_stdout = 0;
-  int i;
-
-  InitOptions(&options);
-
-  for (i = 1; i < argc; i++) {
-    if (StringsEqual(argv[i], "-v")) options.verbose = 1;
-    else if (StringsEqual(argv[i], "-c")) output_to_stdout = 1;
-    else if (StringsEqual(argv[i], "-i5")) options.numiterations = 5;
-    else if (StringsEqual(argv[i], "-i10")) options.numiterations = 10;
-    else if (StringsEqual(argv[i], "-i15")) options.numiterations = 15;
-    else if (StringsEqual(argv[i], "-i25")) options.numiterations = 25;
-    else if (StringsEqual(argv[i], "-i50")) options.numiterations = 50;
-    else if (StringsEqual(argv[i], "-i100")) options.numiterations = 100;
-    else if (StringsEqual(argv[i], "-i250")) options.numiterations = 250;
-    else if (StringsEqual(argv[i], "-i500")) options.numiterations = 500;
-    else if (StringsEqual(argv[i], "-i1000")) options.numiterations = 1000;
-    else if (StringsEqual(argv[i], "-h")) {
-      fprintf(stderr, "Usage: zopfli [OPTION]... FILE\n"
-          "  -h    gives this help\n"
-          "  -c    write the result on standard output, instead of disk"
-          " filename + '.gz'\n"
-          "  -v    verbose mode\n"
-          "  -i5 less compression, but faster\n"
-          "  -i10 less compression, but faster\n"
-          "  -i15 default compression, 15 iterations\n"
-          "  -i25 more compression, but slower\n"
-          "  -i50 more compression, but slower\n"
-          "  -i100 more compression, but slower\n"
-          "  -i250 more compression, but slower\n"
-          "  -i500 more compression, but slower\n"
-          "  -i1000 more compression, but slower\n");
-      return 0;
-    }
-  }
-
-  for (i = 1; i < argc; i++) {
-    if (argv[i][0] != '-') {
-      char* outfilename;
-      filename = argv[i];
-      outfilename = output_to_stdout ?
-          0 : AddStrings(filename, ".gz");
-      if (options.verbose && outfilename) {
-        fprintf(stderr, "Saving to: %s\n", outfilename);
-      }
-      GzipFile(&options, filename, outfilename);
-      free(outfilename);
-    }
-  }
-
-  if (!filename) {
-    fprintf(stderr,
-            "Please provide filename\nFor help, type: %s -h\n", argv[0]);
-  }
-
-  return 0;
-}
diff --git a/gzip_container.c b/gzip_container.c
new file mode 100644
index 0000000..6d38381
--- /dev/null
+++ b/gzip_container.c
@@ -0,0 +1,115 @@
+/*
+Copyright 2013 Google Inc. All Rights Reserved.
+
+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
+
+    http://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.
+
+Author: lode.vandevenne@gmail.com (Lode Vandevenne)
+Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
+*/
+
+#include "gzip_container.h"
+
+#include <stdio.h>
+
+#include "deflate.h"
+
+/* Table of CRCs of all 8-bit messages. */
+static unsigned long crc_table[256];
+
+/* Flag: has the table been computed? Initially false. */
+static int crc_table_computed = 0;
+
+/* Makes the table for a fast CRC. */
+void MakeCRCTable() {
+  unsigned long c;
+  int n, k;
+  for (n = 0; n < 256; n++) {
+    c = (unsigned long) n;
+    for (k = 0; k < 8; k++) {
+      if (c & 1) {
+        c = 0xedb88320L ^ (c >> 1);
+      } else {
+        c = c >> 1;
+      }
+    }
+    crc_table[n] = c;
+  }
+  crc_table_computed = 1;
+}
+
+
+/*
+Updates a running crc with the bytes buf[0..len-1] and returns
+the updated crc. The crc should be initialized to zero.
+*/
+unsigned long UpdateCRC(unsigned long crc,
+                        const unsigned char *buf, size_t len) {
+  unsigned long c = crc ^ 0xffffffffL;
+  unsigned n;
+
+  if (!crc_table_computed)
+    MakeCRCTable();
+  for (n = 0; n < len; n++) {
+    c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
+  }
+  return c ^ 0xffffffffL;
+}
+
+/* Returns the CRC of the bytes buf[0..len-1]. */
+unsigned long CRC(const unsigned char* buf, int len) {
+  return UpdateCRC(0L, buf, len);
+}
+
+/*
+Compresses the data according to the gzip specification.
+*/
+void GzipCompress(const Options* options,
+                  const unsigned char* in, size_t insize,
+                  unsigned char** out, size_t* outsize) {
+  unsigned long crcvalue = CRC(in, insize);
+  unsigned char bp = 0;
+
+  APPEND_DATA(31, out, outsize);  /* ID1 */
+  APPEND_DATA(139, out, outsize);  /* ID2 */
+  APPEND_DATA(8, out, outsize);  /* CM */
+  APPEND_DATA(0, out, outsize);  /* FLG */
+  /* MTIME */
+  APPEND_DATA(0, out, outsize);
+  APPEND_DATA(0, out, outsize);
+  APPEND_DATA(0, out, outsize);
+  APPEND_DATA(0, out, outsize);
+
+  APPEND_DATA(2, out, outsize);  /* XFL, 2 indicates best compression. */
+  APPEND_DATA(3, out, outsize);  /* OS follows Unix conventions. */
+
+  Deflate(options, 2 /* Dynamic block */, 1, in, insize, &bp, out, outsize);
+
+  /* CRC */
+  APPEND_DATA(crcvalue % 256, out, outsize);
+  APPEND_DATA((crcvalue >> 8) % 256, out, outsize);
+  APPEND_DATA((crcvalue >> 16) % 256, out, outsize);
+  APPEND_DATA((crcvalue >> 24) % 256, out, outsize);
+
+  /* ISIZE */
+  APPEND_DATA(insize % 256, out, outsize);
+  APPEND_DATA((insize >> 8) % 256, out, outsize);
+  APPEND_DATA((insize >> 16) % 256, out, outsize);
+  APPEND_DATA((insize >> 24) % 256, out, outsize);
+
+  if (options->verbose) {
+    fprintf(stderr,
+            "Original Size: %d, Compressed: %d, Compression: %f%% Removed\n",
+            (int)insize, (int)*outsize,
+            100.0f * (float)(insize - *outsize) / (float)insize);
+  }
+}
diff --git a/gzip_container.h b/gzip_container.h
new file mode 100644
index 0000000..c03e9cd
--- /dev/null
+++ b/gzip_container.h
@@ -0,0 +1,42 @@
+/*
+Copyright 2013 Google Inc. All Rights Reserved.
+
+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
+
+    http://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.
+
+Author: lode.vandevenne@gmail.com (Lode Vandevenne)
+Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
+*/
+
+#ifndef ZOPFLI_GZIP_H_
+#define ZOPFLI_GZIP_H_
+
+/*
+Functions to compress according to the Gzip specification.
+*/
+
+#include "util.h"
+
+/*
+Compresses according to the gzip specification and append the compressed
+result to the output.
+
+options: global program options
+out: pointer to the dynamic output array to which the result is appended. Must
+  be freed after use.
+outsize: pointer to the dynamic output array size.
+*/
+void GzipCompress(const Options* options,
+                  const unsigned char* in, size_t insize,
+                  unsigned char** out, size_t* outsize);
+
+#endif  /* ZOPFLI_GZIP_H_ */
diff --git a/squeeze.c b/squeeze.c
index 4a72f5a..1620783 100644
--- a/squeeze.c
+++ b/squeeze.c
@@ -205,8 +205,7 @@ static double GetBestLengths(BlockState *s,
                              unsigned short* length_array) {
   /* Best cost to get here so far. */
   size_t blocksize = inend - instart;
-  float* costs = (float*)malloc(sizeof(float) * (blocksize + 1));
-
+  float* costs;
   size_t i = 0, k;
   unsigned short leng;
   unsigned short dist;
@@ -217,10 +216,11 @@ static double GetBestLengths(BlockState *s,
   double result;
   double mincost = GetCostModelMinCost(costmodel, costcontext);
 
-  if (!costs) exit(-1); /* Allocation failed. */
-
   if (instart == inend) return 0;
 
+  costs = (float*)malloc(sizeof(float) * (blocksize + 1));
+  if (!costs) exit(-1); /* Allocation failed. */
+
   InitHash(WINDOW_SIZE, h);
   WarmupHash(in, windowstart, inend, h);
   for (i = windowstart; i < instart; i++) {
diff --git a/zlib_container.c b/zlib_container.c
new file mode 100644
index 0000000..b77d023
--- /dev/null
+++ b/zlib_container.c
@@ -0,0 +1,78 @@
+/*
+Copyright 2013 Google Inc. All Rights Reserved.
+
+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
+
+    http://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.
+
+Author: lode.vandevenne@gmail.com (Lode Vandevenne)
+Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
+*/
+
+#include "zlib_container.h"
+
+#include <stdio.h>
+
+#include "deflate.h"
+
+
+/* Calculates the adler32 checksum of the data */
+static unsigned adler32(const unsigned char* data, size_t size)
+{
+  static const unsigned sums_overflow = 5550;
+  unsigned s1 = 1;
+  unsigned s2 = 1 >> 16;
+
+  while (size > 0) {
+    size_t amount = size > sums_overflow ? sums_overflow : size;
+    size -= amount;
+    while (amount > 0) {
+      s1 += (*data++);
+      s2 += s1;
+      amount--;
+    }
+    s1 %= 65521;
+    s2 %= 65521;
+  }
+
+  return (s2 << 16) | s1;
+}
+
+void ZlibCompress(const Options* options,
+                  const unsigned char* in, size_t insize,
+                  unsigned char** out, size_t* outsize) {
+  unsigned char bitpointer = 0;
+  unsigned checksum = adler32(in, (unsigned)insize);
+  unsigned cmf = 120;  /* CM 8, CINFO 7. See zlib spec.*/
+  unsigned flevel = 0;
+  unsigned fdict = 0;
+  unsigned cmfflg = 256 * cmf + fdict * 32 + flevel * 64;
+  unsigned fcheck = 31 - cmfflg % 31;
+  cmfflg += fcheck;
+
+  APPEND_DATA(cmfflg / 256, out, outsize);
+  APPEND_DATA(cmfflg % 256, out, outsize);
+
+  Deflate(options, 2 /* dynamic block */, 1 /* final */,
+      in, insize, &bitpointer, out, outsize);
+
+  APPEND_DATA((checksum >> 24) % 256, out, outsize);
+  APPEND_DATA((checksum >> 16) % 256, out, outsize);
+  APPEND_DATA((checksum >> 8) % 256, out, outsize);
+  APPEND_DATA(checksum % 256, out, outsize);
+
+  if (options->verbose) {
+    fprintf(stderr,
+            "Original Size: %d, Compressed: %d, Compression: %f%% Removed\n",
+            (int)insize, (int)*outsize,
+            100.0f * (float)(insize - *outsize) / (float)insize);
+  }
+}
diff --git a/zlib_container.h b/zlib_container.h
new file mode 100644
index 0000000..3b11e7a
--- /dev/null
+++ b/zlib_container.h
@@ -0,0 +1,42 @@
+/*
+Copyright 2013 Google Inc. All Rights Reserved.
+
+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
+
+    http://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.
+
+Author: lode.vandevenne@gmail.com (Lode Vandevenne)
+Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
+*/
+
+#ifndef ZOPFLI_ZLIB_H_
+#define ZOPFLI_ZLIB_H_
+
+/*
+Functions to compress according to the Zlib specification.
+*/
+
+#include "util.h"
+
+/*
+Compresses according to the zlib specification and append the compressed
+result to the output.
+
+options: global program options
+out: pointer to the dynamic output array to which the result is appended. Must
+  be freed after use.
+outsize: pointer to the dynamic output array size.
+*/
+void ZlibCompress(const Options* options,
+                  const unsigned char* in, size_t insize,
+                  unsigned char** out, size_t* outsize);
+
+#endif  /* ZOPFLI_ZLIB_H_ */
diff --git a/zopfli.c b/zopfli.c
new file mode 100644
index 0000000..377b43f
--- /dev/null
+++ b/zopfli.c
@@ -0,0 +1,216 @@
+/*
+Copyright 2011 Google Inc. All Rights Reserved.
+
+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
+
+    http://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.
+
+Author: lode.vandevenne@gmail.com (Lode Vandevenne)
+Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
+*/
+
+/*
+Zopfli compressor program. It can output gzip-, zlib- or deflate-compatible
+data. By default it creates a .gz file. This tool can only compress, not
+decompress. Decompression can be done by any standard gzip, zlib or deflate
+decompressor.
+*/
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "deflate.h"
+#include "gzip_container.h"
+#include "zlib_container.h"
+
+/*
+Loads a file into a memory array.
+*/
+static void LoadFile(const char* filename,
+                     unsigned char** out, size_t* outsize) {
+  FILE* file;
+
+  *out = 0;
+  *outsize = 0;
+  file = fopen(filename, "rb");
+  if (!file) return;
+
+  fseek(file , 0 , SEEK_END);
+  *outsize = ftell(file);
+  rewind(file);
+
+  *out = (unsigned char*)malloc(*outsize);
+
+  if (*outsize && (*out)) {
+    size_t testsize = fread(*out, 1, *outsize, file);
+    if (testsize != *outsize) {
+      /* It could be a directory */
+      free(*out);
+      *out = 0;
+      *outsize = 0;
+    }
+  }
+
+  assert(!(*outsize) || out);  /* If size is not zero, out must be allocated. */
+  fclose(file);
+}
+
+/*
+Saves a file from a memory array, overwriting the file if it existed.
+*/
+static void SaveFile(const char* filename,
+                     const unsigned char* in, size_t insize) {
+  FILE* file = fopen(filename, "wb" );
+  assert(file);
+  fwrite((char*)in, 1, insize, file);
+  fclose(file);
+}
+
+typedef enum {
+  OUTPUT_GZIP,
+  OUTPUT_ZLIB,
+  OUTPUT_DEFLATE
+} OutputType;
+
+/*
+outfilename: filename to write output to, or 0 to write to stdout instead
+*/
+void CompressFile(const Options* options,
+                  OutputType output_type,
+                  const char* infilename,
+                  const char* outfilename) {
+  unsigned char* in;
+  size_t insize;
+  unsigned char* out = 0;
+  size_t outsize = 0;
+  LoadFile(infilename, &in, &insize);
+  if (insize == 0) {
+    fprintf(stderr, "Invalid filename: %s\n", infilename);
+    return;
+  }
+  if (output_type == OUTPUT_GZIP) {
+    GzipCompress(options, in, insize, &out, &outsize);
+  } else if (output_type == OUTPUT_ZLIB) {
+    ZlibCompress(options, in, insize, &out, &outsize);
+  } else if (output_type == OUTPUT_DEFLATE) {
+    unsigned char bp = 0;
+    Deflate(options, 2 /* Dynamic block */, 1, in, insize, &bp, &out, &outsize);
+  } else {
+    assert(0);
+  }
+  if (outfilename) {
+    SaveFile(outfilename, out, outsize);
+  } else {
+    size_t i;
+    for (i = 0; i < outsize; i++) {
+      /* Works only if terminal does not convert newlines. */
+      printf("%c", out[i]);
+    }
+  }
+
+  free(out);
+  free(in);
+}
+
+/*
+Add two strings together. Size does not matter. Result must be freed.
+*/
+static char* AddStrings(const char* str1, const char* str2) {
+  size_t len = strlen(str1) + strlen(str2);
+  char* result = (char*)malloc(len + 1);
+  if (!result) exit(-1); /* Allocation failed. */
+  strcpy(result, str1);
+  strcat(result, str2);
+  return result;
+}
+
+static char StringsEqual(const char* str1, const char* str2) {
+  return strcmp(str1, str2) == 0;
+}
+
+int main(int argc, char* argv[]) {
+  Options options;
+  const char* filename = 0;
+  int output_to_stdout = 0;
+  int i;
+  OutputType output_type = OUTPUT_GZIP;
+
+  InitOptions(&options);
+
+  for (i = 1; i < argc; i++) {
+    if (StringsEqual(argv[i], "-v")) options.verbose = 1;
+    else if (StringsEqual(argv[i], "-c")) output_to_stdout = 1;
+    else if (StringsEqual(argv[i], "--deflate")) output_type = OUTPUT_DEFLATE;
+    else if (StringsEqual(argv[i], "--zlib")) output_type = OUTPUT_ZLIB;
+    else if (StringsEqual(argv[i], "--gzip")) output_type = OUTPUT_GZIP;
+    else if (StringsEqual(argv[i], "--i5")) options.numiterations = 5;
+    else if (StringsEqual(argv[i], "--i10")) options.numiterations = 10;
+    else if (StringsEqual(argv[i], "--i15")) options.numiterations = 15;
+    else if (StringsEqual(argv[i], "--i25")) options.numiterations = 25;
+    else if (StringsEqual(argv[i], "--i50")) options.numiterations = 50;
+    else if (StringsEqual(argv[i], "--i100")) options.numiterations = 100;
+    else if (StringsEqual(argv[i], "--i250")) options.numiterations = 250;
+    else if (StringsEqual(argv[i], "--i500")) options.numiterations = 500;
+    else if (StringsEqual(argv[i], "--i1000")) options.numiterations = 1000;
+    else if (StringsEqual(argv[i], "-h")) {
+      fprintf(stderr, "Usage: zopfli [OPTION]... FILE\n"
+          "  -h    gives this help\n"
+          "  -c    write the result on standard output, instead of disk"
+          " filename + '.gz'\n"
+          "  -v    verbose mode\n"
+          "  --gzip  output to gzip format (default)\n"
+          "  --deflate  output to deflate format instead of gzip\n"
+          "  --zlib  output to zlib format instead of gzip\n");
+      fprintf(stderr, "  --i5  less compression, but faster\n"
+          "  --i10  less compression, but faster\n"
+          "  --i15  default compression, 15 iterations\n"
+          "  --i25  more compression, but slower\n"
+          "  --i50  more compression, but slower\n"
+          "  --i100  more compression, but slower\n"
+          "  --i250  more compression, but slower\n"
+          "  --i500  more compression, but slower\n"
+          "  --i1000  more compression, but slower\n");
+      return 0;
+    }
+  }
+
+  for (i = 1; i < argc; i++) {
+    if (argv[i][0] != '-') {
+      char* outfilename;
+      filename = argv[i];
+      if (output_to_stdout) {
+        outfilename = 0;
+      } else if (output_type == OUTPUT_GZIP) {
+        outfilename = AddStrings(filename, ".gz");
+      } else if (output_type == OUTPUT_ZLIB) {
+        outfilename = AddStrings(filename, ".zlib");
+      } else if (output_type == OUTPUT_DEFLATE) {
+        outfilename = AddStrings(filename, ".deflate");
+      } else {
+        assert(0);
+      }
+      if (options.verbose && outfilename) {
+        fprintf(stderr, "Saving to: %s\n", outfilename);
+      }
+      CompressFile(&options, output_type, filename, outfilename);
+      free(outfilename);
+    }
+  }
+
+  if (!filename) {
+    fprintf(stderr,
+            "Please provide filename\nFor help, type: %s -h\n", argv[0]);
+  }
+
+  return 0;
+}