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