Some work

src/memory.h

@@ -2,6 +2,7 @@
 #define INCLUDED_MEMORY_H
 
 #include <float.h>
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -18,6 +19,12 @@
 #    define ALWAYS_INLINE inline
 #endif
 
+#if __has_attribute(format)
+#    define FORMAT(n, m) __attribute__((format(printf, n, m)))
+#else
+#    define FORMAT(n, m)
+#endif
+
 // Byte order stuff
 typedef enum {
     ENDIAN_LITTLE,
@@ -123,4 +130,40 @@ static ALWAYS_INLINE void add_timespecs(const struct timespec *t1,
     out->tv_nsec = nsec;
 }
 
+typedef struct {
+    // this is actually size + 1 bytes for the null byte
+    char *buffer;
+    size_t size;
+    size_t nchars;
+} StringStream;
+
+static inline void string_stream_init(StringStream *restrict stream) {
+    stream->buffer = lisp_malloc(1);
+    stream->size = 0;
+    stream->buffer[stream->size] = '\0';
+    stream->nchars = 0;
+}
+
+static inline void string_stream_free(StringStream *restrict stream) {
+    lisp_free(stream->buffer);
+}
+
+static inline void string_stream_steal(StringStream *restrict stream,
+                                       char **restrict out,
+                                       size_t *restrict out_length) {
+    *out = stream->buffer;
+    *out_length = stream->nchars;
+}
+
+int string_stream_printf(StringStream *restrict stream,
+                         const char *restrict format, ...) FORMAT(2, 3);
+int string_stream_vprintf(StringStream *restrict stream,
+                          const char *restrict format, va_list args);
+
+// Get the next line in BUF starting at *START (or &buf[0] if *START is
+// NULL). Store the length of the line in LENGTH. BUF is BUF_LENGTH bytes
+// long. Return true if we found another line and false otherwise.
+bool strgetline(const char *restrict buf, size_t buf_length,
+                const char **restrict start, size_t *restrict length);
+
 #endif