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376 lines
12 KiB
C++
376 lines
12 KiB
C++
// ImGui - binary_to_compressed_c.cpp
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// Helper tool to turn a file into a C array.
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// The data is first compressed with stb_compress() to reduce source code size.
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// Then encoded in Base85 to fit in a string so we can fit roughly 4 bytes of compressed data into 5 bytes of source code (suggested by @mmalex)
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// (If we used 32-bits constants it would require take 11 bytes of source code to encode 4 bytes.)
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// Useful if you want to embed fonts into your code.
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// Note that even with compression, the output array is likely to be bigger than the binary file..
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// Load compressed TTF fonts with ImGui::GetIO().Fonts->AddFontFromMemoryCompressedTTF()
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#define _CRT_SECURE_NO_WARNINGS
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <assert.h>
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// stb_compress* from stb.h - declaration
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typedef unsigned int stb_uint;
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typedef unsigned char stb_uchar;
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stb_uint stb_compress(stb_uchar *out,stb_uchar *in,stb_uint len);
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static bool binary_to_compressed_c(const char* filename, const char* symbol, bool use_base85_encoding, bool use_compression);
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int main(int argc, char** argv)
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{
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if (argc < 3)
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{
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printf("Syntax: %s [-base85] [-nocompress] <inputfile> <symbolname>\n", argv[0]);
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return 0;
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}
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int argn = 1;
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bool use_base85_encoding = false;
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bool use_compression = true;
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if (argv[argn][0] == '-')
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{
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if (strcmp(argv[argn], "-base85") == 0) { use_base85_encoding = true; argn++; }
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else if (strcmp(argv[argn], "-nocompress") == 0) { use_compression = false; argn++; }
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else
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{
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printf("Unknown argument: '%s'\n", argv[argn]);
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return 1;
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}
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}
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binary_to_compressed_c(argv[argn], argv[argn+1], use_base85_encoding, use_compression);
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return 1;
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}
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char Encode85Byte(unsigned int x)
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{
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x = (x % 85) + 35;
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return (x>='\\') ? x+1 : x;
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}
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bool binary_to_compressed_c(const char* filename, const char* symbol, bool use_base85_encoding, bool use_compression)
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{
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// Read file
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FILE* f = fopen(filename, "rb");
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if (!f) return false;
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int data_sz;
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if (fseek(f, 0, SEEK_END) || (data_sz = (int)ftell(f)) == -1 || fseek(f, 0, SEEK_SET)) { fclose(f); return false; }
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char* data = new char[data_sz+4];
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if (fread(data, 1, data_sz, f) != (size_t)data_sz) { fclose(f); delete[] data; return false; }
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memset((void *)(((char*)data) + data_sz), 0, 4);
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fclose(f);
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// Compress
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int maxlen = data_sz + 512 + (data_sz >> 2) + sizeof(int); // total guess
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char* compressed = use_compression ? new char[maxlen] : data;
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int compressed_sz = use_compression ? stb_compress((stb_uchar*)compressed, (stb_uchar*)data, data_sz) : data_sz;
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if (use_compression)
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memset(compressed + compressed_sz, 0, maxlen - compressed_sz);
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// Output as Base85 encoded
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FILE* out = stdout;
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fprintf(out, "// File: '%s' (%d bytes)\n", filename, (int)data_sz);
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fprintf(out, "// Exported using binary_to_compressed_c.cpp\n");
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const char* compressed_str = use_compression ? "compressed_" : "";
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if (use_base85_encoding)
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{
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fprintf(out, "static const char %s_%sdata_base85[%d+1] =\n \"", symbol, compressed_str, (int)((compressed_sz+3)/4)*5);
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char prev_c = 0;
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for (int src_i = 0; src_i < compressed_sz; src_i += 4)
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{
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// This is made a little more complicated by the fact that ??X sequences are interpreted as trigraphs by old C/C++ compilers. So we need to escape pairs of ??.
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unsigned int d = *(unsigned int*)(compressed + src_i);
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for (unsigned int n5 = 0; n5 < 5; n5++, d /= 85)
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{
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char c = Encode85Byte(d);
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fprintf(out, (c == '?' && prev_c == '?') ? "\\%c" : "%c", c);
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prev_c = c;
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}
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if ((src_i % 112) == 112-4)
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fprintf(out, "\"\n \"");
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}
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fprintf(out, "\";\n\n");
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}
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else
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{
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fprintf(out, "static const unsigned int %s_%ssize = %d;\n", symbol, compressed_str, (int)compressed_sz);
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fprintf(out, "static const unsigned int %s_%sdata[%d/4] =\n{", symbol, compressed_str, (int)((compressed_sz+3)/4)*4);
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int column = 0;
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for (int i = 0; i < compressed_sz; i += 4)
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{
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unsigned int d = *(unsigned int*)(compressed + i);
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if ((column++ % 12) == 0)
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fprintf(out, "\n 0x%08x, ", d);
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else
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fprintf(out, "0x%08x, ", d);
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}
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fprintf(out, "\n};\n\n");
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}
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// Cleanup
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delete[] data;
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if (use_compression)
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delete[] compressed;
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return true;
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}
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// stb_compress* from stb.h - definition
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//////////////////// compressor ///////////////////////
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static stb_uint stb_adler32(stb_uint adler32, stb_uchar *buffer, stb_uint buflen)
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{
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const unsigned long ADLER_MOD = 65521;
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unsigned long s1 = adler32 & 0xffff, s2 = adler32 >> 16;
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unsigned long blocklen, i;
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blocklen = buflen % 5552;
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while (buflen) {
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for (i=0; i + 7 < blocklen; i += 8) {
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s1 += buffer[0], s2 += s1;
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s1 += buffer[1], s2 += s1;
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s1 += buffer[2], s2 += s1;
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s1 += buffer[3], s2 += s1;
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s1 += buffer[4], s2 += s1;
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s1 += buffer[5], s2 += s1;
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s1 += buffer[6], s2 += s1;
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s1 += buffer[7], s2 += s1;
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buffer += 8;
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}
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for (; i < blocklen; ++i)
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s1 += *buffer++, s2 += s1;
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s1 %= ADLER_MOD, s2 %= ADLER_MOD;
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buflen -= blocklen;
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blocklen = 5552;
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}
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return (s2 << 16) + s1;
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}
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static unsigned int stb_matchlen(stb_uchar *m1, stb_uchar *m2, stb_uint maxlen)
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{
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stb_uint i;
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for (i=0; i < maxlen; ++i)
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if (m1[i] != m2[i]) return i;
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return i;
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}
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// simple implementation that just takes the source data in a big block
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static stb_uchar *stb__out;
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static FILE *stb__outfile;
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static stb_uint stb__outbytes;
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static void stb__write(unsigned char v)
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{
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fputc(v, stb__outfile);
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++stb__outbytes;
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}
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#define stb_out(v) (stb__out ? *stb__out++ = (stb_uchar) (v) : stb__write((stb_uchar) (v)))
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static void stb_out2(stb_uint v)
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{
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stb_out(v >> 8);
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stb_out(v);
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}
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static void stb_out3(stb_uint v) { stb_out(v >> 16); stb_out(v >> 8); stb_out(v); }
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static void stb_out4(stb_uint v) { stb_out(v >> 24); stb_out(v >> 16);
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stb_out(v >> 8 ); stb_out(v); }
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static void outliterals(stb_uchar *in, int numlit)
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{
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while (numlit > 65536) {
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outliterals(in,65536);
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in += 65536;
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numlit -= 65536;
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}
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if (numlit == 0) ;
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else if (numlit <= 32) stb_out (0x000020 + numlit-1);
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else if (numlit <= 2048) stb_out2(0x000800 + numlit-1);
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else /* numlit <= 65536) */ stb_out3(0x070000 + numlit-1);
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if (stb__out) {
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memcpy(stb__out,in,numlit);
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stb__out += numlit;
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} else
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fwrite(in, 1, numlit, stb__outfile);
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}
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static int stb__window = 0x40000; // 256K
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static int stb_not_crap(int best, int dist)
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{
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return ((best > 2 && dist <= 0x00100)
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|| (best > 5 && dist <= 0x04000)
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|| (best > 7 && dist <= 0x80000));
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}
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static stb_uint stb__hashsize = 32768;
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// note that you can play with the hashing functions all you
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// want without needing to change the decompressor
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#define stb__hc(q,h,c) (((h) << 7) + ((h) >> 25) + q[c])
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#define stb__hc2(q,h,c,d) (((h) << 14) + ((h) >> 18) + (q[c] << 7) + q[d])
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#define stb__hc3(q,c,d,e) ((q[c] << 14) + (q[d] << 7) + q[e])
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static unsigned int stb__running_adler;
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static int stb_compress_chunk(stb_uchar *history,
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stb_uchar *start,
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stb_uchar *end,
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int length,
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int *pending_literals,
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stb_uchar **chash,
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stb_uint mask)
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{
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(void)history;
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int window = stb__window;
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stb_uint match_max;
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stb_uchar *lit_start = start - *pending_literals;
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stb_uchar *q = start;
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#define STB__SCRAMBLE(h) (((h) + ((h) >> 16)) & mask)
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// stop short of the end so we don't scan off the end doing
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// the hashing; this means we won't compress the last few bytes
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// unless they were part of something longer
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while (q < start+length && q+12 < end) {
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int m;
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stb_uint h1,h2,h3,h4, h;
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stb_uchar *t;
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int best = 2, dist=0;
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if (q+65536 > end)
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match_max = end-q;
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else
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match_max = 65536;
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#define stb__nc(b,d) ((d) <= window && ((b) > 9 || stb_not_crap(b,d)))
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#define STB__TRY(t,p) /* avoid retrying a match we already tried */ \
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if (p ? dist != q-t : 1) \
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if ((m = stb_matchlen(t, q, match_max)) > best) \
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if (stb__nc(m,q-(t))) \
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best = m, dist = q - (t)
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// rather than search for all matches, only try 4 candidate locations,
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// chosen based on 4 different hash functions of different lengths.
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// this strategy is inspired by LZO; hashing is unrolled here using the
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// 'hc' macro
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h = stb__hc3(q,0, 1, 2); h1 = STB__SCRAMBLE(h);
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t = chash[h1]; if (t) STB__TRY(t,0);
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h = stb__hc2(q,h, 3, 4); h2 = STB__SCRAMBLE(h);
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h = stb__hc2(q,h, 5, 6); t = chash[h2]; if (t) STB__TRY(t,1);
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h = stb__hc2(q,h, 7, 8); h3 = STB__SCRAMBLE(h);
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h = stb__hc2(q,h, 9,10); t = chash[h3]; if (t) STB__TRY(t,1);
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h = stb__hc2(q,h,11,12); h4 = STB__SCRAMBLE(h);
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t = chash[h4]; if (t) STB__TRY(t,1);
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// because we use a shared hash table, can only update it
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// _after_ we've probed all of them
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chash[h1] = chash[h2] = chash[h3] = chash[h4] = q;
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if (best > 2)
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assert(dist > 0);
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// see if our best match qualifies
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if (best < 3) { // fast path literals
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++q;
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} else if (best > 2 && best <= 0x80 && dist <= 0x100) {
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outliterals(lit_start, q-lit_start); lit_start = (q += best);
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stb_out(0x80 + best-1);
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stb_out(dist-1);
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} else if (best > 5 && best <= 0x100 && dist <= 0x4000) {
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outliterals(lit_start, q-lit_start); lit_start = (q += best);
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stb_out2(0x4000 + dist-1);
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stb_out(best-1);
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} else if (best > 7 && best <= 0x100 && dist <= 0x80000) {
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outliterals(lit_start, q-lit_start); lit_start = (q += best);
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stb_out3(0x180000 + dist-1);
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stb_out(best-1);
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} else if (best > 8 && best <= 0x10000 && dist <= 0x80000) {
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outliterals(lit_start, q-lit_start); lit_start = (q += best);
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stb_out3(0x100000 + dist-1);
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stb_out2(best-1);
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} else if (best > 9 && dist <= 0x1000000) {
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if (best > 65536) best = 65536;
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outliterals(lit_start, q-lit_start); lit_start = (q += best);
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if (best <= 0x100) {
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stb_out(0x06);
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stb_out3(dist-1);
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stb_out(best-1);
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} else {
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stb_out(0x04);
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stb_out3(dist-1);
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stb_out2(best-1);
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}
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} else { // fallback literals if no match was a balanced tradeoff
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++q;
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}
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}
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// if we didn't get all the way, add the rest to literals
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if (q-start < length)
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q = start+length;
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// the literals are everything from lit_start to q
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*pending_literals = (q - lit_start);
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stb__running_adler = stb_adler32(stb__running_adler, start, q - start);
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return q - start;
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}
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static int stb_compress_inner(stb_uchar *input, stb_uint length)
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{
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int literals = 0;
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stb_uint len,i;
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stb_uchar **chash;
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chash = (stb_uchar**) malloc(stb__hashsize * sizeof(stb_uchar*));
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if (chash == NULL) return 0; // failure
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for (i=0; i < stb__hashsize; ++i)
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chash[i] = NULL;
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// stream signature
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stb_out(0x57); stb_out(0xbc);
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stb_out2(0);
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stb_out4(0); // 64-bit length requires 32-bit leading 0
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stb_out4(length);
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stb_out4(stb__window);
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stb__running_adler = 1;
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len = stb_compress_chunk(input, input, input+length, length, &literals, chash, stb__hashsize-1);
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assert(len == length);
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outliterals(input+length - literals, literals);
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free(chash);
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stb_out2(0x05fa); // end opcode
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stb_out4(stb__running_adler);
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return 1; // success
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}
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stb_uint stb_compress(stb_uchar *out, stb_uchar *input, stb_uint length)
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{
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stb__out = out;
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stb__outfile = NULL;
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stb_compress_inner(input, length);
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return stb__out - out;
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}
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