В этом примере показано, как сгенерировать автономную библиотеку C из кода MATLAB ®, который читает файл с диска с помощью функций fopen/fread/fclose.
readfile
ФункцияThe readfile.m
функция принимает имя файла (или путь) в качестве входных данных и возвращает строку, содержащую содержимое файла.
type readfile
% y = readfile(filename) % Read file 'filename' and return a MATLAB string with the contents % of the file. function y = readfile(filename) %#codegen % Put class and size constraints on function input. assert(isa(filename, 'char')); assert(size(filename, 1) == 1); assert(size(filename, 2) <= 1024); % Call fopen(filename 'r'), but we need to convert the MATLAB % string into a C type string (which is the same string with the % NUL (\0) string terminator). f = fopen(filename, 'r'); % Call fseek(f, 0, SEEK_END) to set file position to the end of % the file. fseek(f, 0, 'eof'); % Call ftell(f) which will return the length of the file in bytes % (as current file position is at the end of the file). filelen = int32(ftell(f)); % Reset current file position fseek(f,0,'bof'); % Initialize a buffer maxBufferSize = int32(2^16); buffer = zeros(1, maxBufferSize,'uint8'); % Remaining is the number of bytes to read (from the file) remaining = filelen; % Index is the current position to read into the buffer index = int32(1); while remaining > 0 % Buffer overflow? if remaining + index > size(buffer,2) fprintf('Attempt to read file which is bigger than internal buffer.\n'); fprintf('Current buffer size is %d bytes and file size is %d bytes.\n', maxBufferSize, filelen); break end % Read as much as possible from the file into internal buffer [dataRead, nread] = fread(f,remaining, 'char'); buffer(index:index+nread-1) = dataRead; n = int32(nread); if n == 0 % Nothing more to read break; end % Did something went wrong when reading? if n < 0 fprintf('Could not read from file: %d.\n', n); break; end % Update state variables remaining = remaining - n; index = index + n; end % Close file fclose(f); y = char(buffer(1:index));
Сгенерируйте MEX-функцию с помощью codegen
команда.
codegen readfile
Code generation successful.
Перед генерацией Кода С необходимо сначала протестировать MEX-функцию в MATLAB, чтобы убедиться, что она функционально эквивалентна оригинальному коду MATLAB и что никаких ошибок времени выполнения не происходит. По умолчанию codegen
генерирует MEX-функцию с именем readfile_mex
в текущей папке. Это позволяет вам протестировать код MATLAB и MEX-функцию и сравнить результаты.
Вызовите сгенерированную MEX-функцию и отобразите размер возвращаемой строки и ее первых 100 символов.
y = readfile_mex('readfile.m');
size(y)
ans = 1×2
1 1857
y(1:100)
ans = '% y = readfile(filename) % Read file 'filename' and return a MATLAB string with the contents % of th'
codegen -config:lib readfile
Code generation successful.
Использование codegen
с заданным -config cfg
опция создает автономную библиотеку C.
По умолчанию код, сгенерированный для библиотеки, находится в папке codegen/lib/readfile/
.
Файлы:
dir codegen/lib/readfile/
. readfile.a readfile_initialize.h .. readfile.c readfile_initialize.o .gitignore readfile.h readfile_rtw.mk _clang-format readfile.o readfile_rtwutil.c buildInfo.mat readfile_data.c readfile_rtwutil.h codeInfo.mat readfile_data.h readfile_rtwutil.o codedescriptor.dmr readfile_data.o readfile_terminate.c compileInfo.mat readfile_emxAPI.c readfile_terminate.h defines.txt readfile_emxAPI.h readfile_terminate.o examples readfile_emxAPI.o readfile_types.h fileManager.c readfile_emxutil.c rtw_proj.tmw fileManager.h readfile_emxutil.h rtwtypes.h fileManager.o readfile_emxutil.o interface readfile_initialize.c
readfile.c
Функцияtype codegen/lib/readfile/readfile.c
/* * File: readfile.c * * MATLAB Coder version : 5.2 * C/C++ source code generated on : 21-Apr-2021 01:24:57 */ /* Include Files */ #include "readfile.h" #include "fileManager.h" #include "readfile_data.h" #include "readfile_emxutil.h" #include "readfile_initialize.h" #include "readfile_rtwutil.h" #include "readfile_types.h" #include <stddef.h> #include <stdio.h> #include <string.h> /* Function Definitions */ /* * Put class and size constraints on function input. * * Arguments : const char filename_data[] * const int filename_size[2] * emxArray_char_T *y * Return Type : void */ void readfile(const char filename_data[], const int filename_size[2], emxArray_char_T *y) { FILE *filestar; int wherefrom; long position_t; size_t nBytes; size_t numReadSizeT; emxArray_uint8_T *At; emxArray_uint8_T *b_At; double position; int b_index; int bytesOut; int c; int i; int num2Read; int numRead; int other2Read; int remaining; short bdims_idx_0; unsigned char buffer[65536]; char tbuf[1024]; signed char fileid; boolean_T doEOF; boolean_T exitg1; if (!isInitialized_readfile) { readfile_initialize(); } /* y = readfile(filename) */ /* Read file 'filename' and return a MATLAB string with the contents */ /* of the file. */ /* Call fopen(filename 'r'), but we need to convert the MATLAB */ /* string into a C type string (which is the same string with the */ /* NUL (\0) string terminator). */ fileid = cfopen(filename_data, filename_size, "rb"); /* Call fseek(f, 0, SEEK_END) to set file position to the end of */ /* the file. */ wherefrom = SEEK_END; filestar = fileManager(fileid); if ((fileid == 0) || (fileid == 1) || (fileid == 2)) { filestar = NULL; } if (!(filestar == NULL)) { fseek(filestar, (long int)0.0, wherefrom); } /* Call ftell(f) which will return the length of the file in bytes */ /* (as current file position is at the end of the file). */ filestar = fileManager(fileid); if ((fileid == 0) || (fileid == 1) || (fileid == 2)) { filestar = NULL; } if (filestar == NULL) { position = -1.0; } else { position_t = ftell(filestar); position = (double)position_t; } position = rt_roundd_snf(position); if (position < 2.147483648E+9) { if (position >= -2.147483648E+9) { i = (int)position; } else { i = MIN_int32_T; } } else if (position >= 2.147483648E+9) { i = MAX_int32_T; } else { i = 0; } /* Reset current file position */ wherefrom = SEEK_SET; filestar = fileManager(fileid); if ((fileid == 0) || (fileid == 1) || (fileid == 2)) { filestar = NULL; } if (!(filestar == NULL)) { fseek(filestar, (long int)0.0, wherefrom); } /* Initialize a buffer */ memset(&buffer[0], 0, 65536U * sizeof(unsigned char)); /* Remaining is the number of bytes to read (from the file) */ remaining = i; /* Index is the current position to read into the buffer */ b_index = 1; emxInit_uint8_T(&At, 2); emxInit_uint8_T(&b_At, 1); exitg1 = false; while ((!exitg1) && (remaining > 0)) { /* Buffer overflow? */ if (b_index > MAX_int32_T - remaining) { other2Read = MAX_int32_T; } else { other2Read = remaining + b_index; } if (other2Read > 65536) { printf("Attempt to read file which is bigger than internal buffer.\n"); fflush(stdout); printf("Current buffer size is %d bytes and file size is %d bytes.\n", 65536, i); fflush(stdout); exitg1 = true; } else { /* Read as much as possible from the file into internal buffer */ if (remaining >= MAX_int32_T) { c = 1024; doEOF = true; } else { c = remaining; doEOF = false; } nBytes = sizeof(char); filestar = fileManager(fileid); if ((fileid == 0) || (fileid == 1) || (fileid == 2)) { filestar = NULL; } if (!doEOF) { if (filestar == NULL) { b_At->size[0] = 0; bytesOut = 0; } else { numRead = b_At->size[0]; b_At->size[0] = remaining; emxEnsureCapacity_uint8_T(b_At, numRead); if (c > 1024) { bdims_idx_0 = 1024; } else { bdims_idx_0 = (short)c; } bytesOut = 0; numRead = 1; while ((bytesOut < c) && (numRead > 0)) { num2Read = bdims_idx_0; other2Read = c - bytesOut; if (bdims_idx_0 > other2Read) { num2Read = other2Read; } numRead = 0; other2Read = 1; while ((numRead < num2Read) && (other2Read > 0)) { numReadSizeT = fread(&tbuf[numRead], nBytes, num2Read - numRead, filestar); other2Read = (int)numReadSizeT; numRead += (int)numReadSizeT; } for (other2Read = 0; other2Read < numRead; other2Read++) { b_At->data[other2Read + bytesOut] = (unsigned char)tbuf[other2Read]; } bytesOut += numRead; } numRead = bytesOut + 1; num2Read = b_At->size[0]; for (other2Read = numRead; other2Read <= num2Read; other2Read++) { b_At->data[other2Read - 1] = 0U; } if (bytesOut < remaining) { numRead = b_At->size[0]; if (1 > bytesOut) { b_At->size[0] = 0; } else { b_At->size[0] = bytesOut; } emxEnsureCapacity_uint8_T(b_At, numRead); } } } else { At->size[0] = 0; At->size[1] = 1; if (filestar == NULL) { bytesOut = 0; } else { c = 1; bytesOut = 0; while (c > 0) { c = 0; numRead = 1; while ((c < 1024) && (numRead > 0)) { numReadSizeT = fread(&tbuf[c], nBytes, 1024 - c, filestar); numRead = (int)numReadSizeT; c += (int)numReadSizeT; } if (1 > c) { other2Read = 0; } else { other2Read = c; } numRead = b_At->size[0]; b_At->size[0] = At->size[0] + other2Read; emxEnsureCapacity_uint8_T(b_At, numRead); num2Read = At->size[0]; for (numRead = 0; numRead < num2Read; numRead++) { b_At->data[numRead] = At->data[numRead]; } for (numRead = 0; numRead < other2Read; numRead++) { b_At->data[numRead + At->size[0]] = (unsigned char)tbuf[numRead]; } numRead = At->size[0] * At->size[1]; At->size[0] = b_At->size[0]; At->size[1] = 1; emxEnsureCapacity_uint8_T(At, numRead); other2Read = b_At->size[0]; for (numRead = 0; numRead < other2Read; numRead++) { At->data[numRead] = b_At->data[numRead]; } bytesOut += c; } } numRead = b_At->size[0]; b_At->size[0] = At->size[0]; emxEnsureCapacity_uint8_T(b_At, numRead); other2Read = At->size[0]; for (numRead = 0; numRead < other2Read; numRead++) { b_At->data[numRead] = At->data[numRead]; } } position = (double)b_index + (double)bytesOut; if (position < 2.147483648E+9) { if (position >= -2.147483648E+9) { numRead = (int)position; } else { numRead = MIN_int32_T; } } else { numRead = MAX_int32_T; } if (b_index > numRead - 1) { num2Read = -1; numRead = -1; } else { num2Read = b_index - 2; numRead -= 2; } other2Read = numRead - num2Read; for (numRead = 0; numRead < other2Read; numRead++) { buffer[(num2Read + numRead) + 1] = b_At->data[numRead]; } if (bytesOut == 0) { /* Nothing more to read */ exitg1 = true; /* Did something went wrong when reading? */ } else if (bytesOut < 0) { printf("Could not read from file: %d.\n", bytesOut); fflush(stdout); exitg1 = true; } else { /* Update state variables */ remaining -= bytesOut; if ((b_index < 0) && (bytesOut < MIN_int32_T - b_index)) { b_index = MIN_int32_T; } else if ((b_index > 0) && (bytesOut > MAX_int32_T - b_index)) { b_index = MAX_int32_T; } else { b_index += bytesOut; } } } } emxFree_uint8_T(&b_At); emxFree_uint8_T(&At); /* Close file */ cfclose(fileid); i = y->size[0] * y->size[1]; y->size[0] = 1; y->size[1] = b_index; emxEnsureCapacity_char_T(y, i); for (i = 0; i < b_index; i++) { y->data[i] = (signed char)buffer[i]; } } /* * File trailer for readfile.c * * [EOF] */