code / print

   1 #pragma once
   2 
   3 // This file defines a String(...) macro that works with the Boehm GC
   4 // to allocate formatted strings.
   5 #include <gc.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <sys/param.h>
  10 
  11 typedef struct {
  12     char **buffer;
  13     size_t *size;
  14     size_t position;
  15 } gc_stream_t;
  16 
  17 static ssize_t _gc_stream_write(void *cookie, const char *buf, size_t size) {
  18     gc_stream_t *stream = (gc_stream_t *)cookie;
  19     if (stream->position + size + 1 > *stream->size)
  20         *stream->buffer = (char*)GC_REALLOC(*stream->buffer, (*stream->size += MAX(MAX(16, *stream->size/2), size + 1)));
  21     memcpy(&(*stream->buffer)[stream->position], buf, size);
  22     stream->position += size;
  23     (*stream->buffer)[stream->position] = '\0';
  24     return size;
  25 }
  26 
  27 static FILE *gc_memory_stream(char **buf, size_t *size) {
  28     gc_stream_t *stream = (gc_stream_t*)GC_MALLOC(sizeof(gc_stream_t));
  29     stream->size = size;
  30     stream->buffer = buf;
  31     *stream->size = 16;
  32     *stream->buffer = (char*)GC_MALLOC_ATOMIC(*stream->size);
  33     (*stream->buffer)[0] = '\0';
  34     stream->position = 0;
  35     cookie_io_functions_t functions = {.write = _gc_stream_write};
  36     return fopencookie(stream, "w", functions);
  37 }
  38 
  39 #define String(...) ({ \
  40     char *_buf = NULL; \
  41     size_t _size = 0; \
  42     FILE *_stream = gc_memory_stream(&_buf, &_size); \
  43     assert(_stream); \
  44     _fprint(_stream, __VA_ARGS__); \
  45     fflush(_stream); \
  46     _buf; })