remove breaks after return in switch-case

In the base cases of STRINGS and FILES, these functions should be very
quick (operating on stuff in memory), and amortized for pipes.

include/alisp/stream.h

@@ -53,8 +53,11 @@ typedef struct
 
 stream_err_t stream_init_string(stream_t *, const char *, sv_t);
 stream_err_t stream_init_pipe(stream_t *, const char *, FILE *);
+// NOTE: stream_init_file will attempt to read all content from the FILE
+// descriptor.  Use with caution.
 stream_err_t stream_init_file(stream_t *, const char *, FILE *);
-void stream_stop(stream_t *);
+void stream_reset(stream_t *);
+void stream_free(stream_t *);
 
 // End of Content (i.e. we've consumed all cached content/file)
 bool stream_eoc(stream_t *);
@@ -70,6 +73,12 @@ u64 stream_seek(stream_t *, i64);
 u64 stream_seek_forward(stream_t *, u64);
 u64 stream_seek_backward(stream_t *, u64);
 
+// Return a string view to stream data relative to the current position of the
+// stream
+sv_t stream_sv(stream_t *);
+// Return a string view to data from the start of the stream
+sv_t stream_sv_abs(stream_t *);
+
 // Return a relative substring of a given size
 sv_t stream_substr(stream_t *, u64);
 // Return an absolute substring at given index and of given size.

src/reader.c

@@ -17,13 +17,10 @@ const char *read_err_to_cstr(read_err_t err)
   {
   case READ_ERR_OK:
     return "OK";
-    break;
   case READ_ERR_EOF:
     return "EOF";
-    break;
   case READ_ERR_UNKNOWN_CHAR:
     return "UNKNOWN_CHAR";
-    break;
   default:
     FAIL("Unreachable");
   }

src/stream.c

@@ -11,6 +11,8 @@
 
 #include <alisp/base.h>
 #include <alisp/stream.h>
+#include <alisp/sv.h>
+#include <alisp/vec.h>
 
 const char *stream_err_to_cstr(stream_err_t err)
 {
@@ -18,19 +20,14 @@ const char *stream_err_to_cstr(stream_err_t err)
   {
   case STREAM_ERR_INVALID_PTR:
     return "INVALID PTR";
-    break;
   case STREAM_ERR_FILE_NONEXISTENT:
     return "FILE NONEXISTENT";
-    break;
   case STREAM_ERR_FILE_READ:
     return "FILE READ";
-    break;
   case STREAM_ERR_PIPE_NONEXISTENT:
     return "PIPE NONEXISTENT";
-    break;
   case STREAM_ERR_OK:
     return "OK";
-    break;
   default:
     FAIL("Unreachable");
   }
@@ -65,8 +62,6 @@ stream_err_t stream_init_pipe(stream_t *stream, const char *name, FILE *pipe)
   stream->name      = name;
   stream->pipe.file = pipe;
 
-  vec_init(&stream->pipe.cache, STREAM_DEFAULT_CHUNK);
-
   return STREAM_ERR_OK;
 }
 
@@ -82,12 +77,30 @@ stream_err_t stream_init_file(stream_t *stream, const char *name, FILE *pipe)
 
   stream->type      = STREAM_TYPE_FILE;
   stream->name      = name;
-  stream->pipe.file = pipe;
+  stream->pipe.file = NULL;
+
+  // NOTE: We're reading all the data from the file descriptor now.
+  fseek(pipe, 0, SEEK_END);
+  long size = ftell(pipe);
+  fseek(pipe, 0, SEEK_SET);
+  vec_ensure_free(&stream->pipe.cache, size);
+  int read = fread(vec_data(&stream->pipe.cache), 1, size, pipe);
+
+  // These must be equivalent for this function.
+  assert(read == size);
+  stream->pipe.cache.size += size;
 
   return STREAM_ERR_OK;
 }
 
-void stream_stop(stream_t *stream)
+void stream_reset(stream_t *stream)
+{
+  if (!stream)
+    return;
+  stream->position = 0;
+}
+
+void stream_free(stream_t *stream)
 {
   if (!stream)
     return;
@@ -97,11 +110,8 @@ void stream_stop(stream_t *stream)
     free(stream->string.data);
     break;
   case STREAM_TYPE_FILE:
-    // ensure we reset the FILE pointer to the start
-    fseek(stream->pipe.file, 0, SEEK_SET);
-    // fallthrough
   case STREAM_TYPE_PIPE:
-    // Must cleanup vector
+    // Must cleanup caching vector
     vec_free(&stream->pipe.cache);
     break;
   }
@@ -124,31 +134,15 @@ u64 stream_size(stream_t *stream)
   }
 }
 
-bool stream_eos(stream_t *stream)
-{
-  assert(stream);
-  switch (stream->type)
-  {
-  case STREAM_TYPE_STRING:
-    return stream->position >= stream->string.size;
-  case STREAM_TYPE_PIPE:
-  case STREAM_TYPE_FILE:
-    return feof(stream->pipe.file);
-  default:
-    FAIL("Unreachable");
-    return 0;
-  }
-}
-
 bool stream_eoc(stream_t *stream)
 {
   assert(stream);
   switch (stream->type)
   {
-  case STREAM_TYPE_STRING:
-    return stream->position >= stream->string.size;
-  case STREAM_TYPE_PIPE:
   case STREAM_TYPE_FILE:
+  case STREAM_TYPE_STRING:
+    return stream->position >= stream_size(stream);
+  case STREAM_TYPE_PIPE:
     return feof(stream->pipe.file) &&
            stream->position >= stream->pipe.cache.size;
   default:
@@ -160,23 +154,20 @@ bool stream_eoc(stream_t *stream)
 bool stream_chunk(stream_t *stream)
 {
   assert(stream);
-  u64 to_read = STREAM_DEFAULT_CHUNK;
   switch (stream->type)
   {
-  case STREAM_TYPE_STRING:
-    // vacuously true
-    return true;
-  case STREAM_TYPE_PIPE:
-    to_read = 1;
-    // fallthrough
   case STREAM_TYPE_FILE:
+  case STREAM_TYPE_STRING:
+    // nothing to chunk, hence false
+    return false;
+  case STREAM_TYPE_PIPE:
   {
     if (feof(stream->pipe.file))
       // We can't read anymore.  End of the line
       return false;
-    vec_ensure_free(&stream->pipe.cache, to_read);
+    vec_ensure_free(&stream->pipe.cache, STREAM_DEFAULT_CHUNK);
     int read = fread(vec_data(&stream->pipe.cache) + stream->pipe.cache.size, 1,
-                     to_read, stream->pipe.file);
+                     STREAM_DEFAULT_CHUNK, stream->pipe.file);
 
     // If we read something it's a good thing
     if (read > 0)
@@ -185,7 +176,9 @@ bool stream_chunk(stream_t *stream)
       return true;
     }
     else
+    {
       return false;
+    }
   }
   default:
     FAIL("Unreachable");
@@ -202,24 +195,20 @@ char stream_next(stream_t *stream)
 
 char stream_peek(stream_t *stream)
 {
-  // If we've reached end of stream, and end of content, there's really nothing
-  // to check here.
+  // End of the line?  We're done.
   if (stream_eoc(stream))
     return '\0';
 
   switch (stream->type)
   {
-  case STREAM_TYPE_STRING:
-    return stream->string.data[stream->position];
-  case STREAM_TYPE_PIPE:
   case STREAM_TYPE_FILE:
+  case STREAM_TYPE_STRING:
+    return stream_sv(stream).data[0];
+  case STREAM_TYPE_PIPE:
   {
     // Cached already?  We are done.
     if (stream->position < stream->pipe.cache.size)
-    {
-      const char *const str = (char *)vec_data(&stream->pipe.cache);
-      return str[stream->position];
-    }
+      return stream_sv(stream).data[0];
 
     // Try to read chunks in till we've reached it or we're at the end of the
     // file.
@@ -231,7 +220,7 @@ char stream_peek(stream_t *stream)
     // Same principle as the stream_eos(stream) check.
     if (stream->position >= stream->pipe.cache.size)
       return '\0';
-    return ((char *)vec_data(&stream->pipe.cache))[stream->position];
+    return stream_sv(stream).data[0];
   }
   default:
     FAIL("Unreachable");
@@ -246,36 +235,38 @@ u64 stream_seek(stream_t *stream, i64 offset)
   else if (offset > 0)
     return stream_seek_forward(stream, offset);
   else
-    // vacuously successful
-    return true;
+    return 0;
 }
 
 u64 stream_seek_forward(stream_t *stream, u64 offset)
 {
   if (stream_eoc(stream))
     return 0;
+  else if (stream->position + offset < stream_size(stream))
+  {
+    stream->position += offset;
+    return offset;
+  }
 
+  // NOTE: The only case not caught by the above branches is exact-to-end
+  // movement (i.e. offset puts us exactly at the end of the stream) or movement
+  // beyond what we've cached.
   switch (stream->type)
   {
+  case STREAM_TYPE_FILE:
   case STREAM_TYPE_STRING:
   {
-    if (stream->position + offset >= stream->string.size)
-      return 0;
-
+    // Clamp in the case of FILE and STRING movement since they're already
+    // fully cached.
+    if (stream->position + offset >= stream_size(stream))
+      offset = stream_size(stream) - stream->position;
     stream->position += offset;
     return offset;
   }
   case STREAM_TYPE_PIPE:
-  case STREAM_TYPE_FILE:
   {
-    // Similar principle as stream_peek really...
-
-    // Cached already?  We are done.
-    if (stream->position + offset < stream->pipe.cache.size)
-    {
-      stream->position += offset;
-      return offset;
-    }
+    // Pipes may have data remaining that hasn't been cached - we need to chunk
+    // before we can be sure to stop.
 
     // Try to read chunks in till we've reached it or we're at the end of the
     // file.
@@ -284,32 +275,58 @@ u64 stream_seek_forward(stream_t *stream, u64 offset)
          read_chunk = stream_chunk(stream))
       continue;
 
-    // Same principle as the stream_eoc(stream) check.
-    if (stream->position + offset > stream->pipe.cache.size)
-    {
-      offset = stream->pipe.cache.size - stream->position;
-    }
+    // NOTE: We've read everything from the pipe, but the offset is greater.  We
+    // must clamp here.
+    if (stream->position + offset > stream_size(stream))
+      offset = stream_size(stream) - stream->position;
+
     stream->position += offset;
     return offset;
   }
   default:
     FAIL("Unreachable");
-    return 0;
   }
+  return 0;
 }
 
 u64 stream_seek_backward(stream_t *stream, u64 offset)
 {
-  assert(stream);
+  if (!stream)
+    return 0;
   if (stream->position < offset)
-  {
     offset = stream->position;
-  }
 
   stream->position -= offset;
   return offset;
 }
 
+sv_t stream_sv(stream_t *stream)
+{
+  sv_t sv = stream_sv_abs(stream);
+  return sv_chop_left(sv, stream->position);
+}
+
+sv_t stream_sv_abs(stream_t *stream)
+{
+  if (!stream)
+    return SV(NULL, 0);
+  sv_t sv = {0};
+  switch (stream->type)
+  {
+  case STREAM_TYPE_STRING:
+    sv = stream->string;
+    break;
+  case STREAM_TYPE_FILE:
+  case STREAM_TYPE_PIPE:
+    sv = SV((char *)vec_data(&stream->pipe.cache), stream_size(stream));
+    break;
+  default:
+    FAIL("Unreachable");
+    return SV(NULL, 0);
+  }
+  return sv;
+}
+
 sv_t stream_substr(stream_t *stream, u64 size)
 {
   if (stream_eoc(stream))
@@ -324,104 +341,130 @@ sv_t stream_substr(stream_t *stream, u64 size)
   if (successful != size)
     return SV(NULL, 0);
 
-  char *ptr = NULL;
-  switch (stream->type)
-  {
-  case STREAM_TYPE_STRING:
-    ptr = stream->string.data;
-    break;
-  case STREAM_TYPE_PIPE:
-  case STREAM_TYPE_FILE:
-    ptr = (char *)vec_data(&stream->pipe.cache);
-    break;
-  default:
-    FAIL("Unreachable");
-    return SV(NULL, 0);
-  }
-
-  return SV(ptr + stream->position, size);
+  sv_t sv = stream_sv(stream);
+  sv      = sv_truncate(sv, size);
+  return sv;
 }
 
 sv_t stream_substr_abs(stream_t *stream, u64 index, u64 size)
 {
   switch (stream->type)
   {
-  case STREAM_TYPE_STRING:
-    if (index + size <= stream_size(stream))
-      return SV(stream->string.data + index, size);
-    return SV(NULL, 0);
   case STREAM_TYPE_PIPE:
-  case STREAM_TYPE_FILE:
   {
-    if (index + size <= stream_size(stream))
-      return SV((char *)vec_data(&stream->pipe.cache) + index, size);
-    // (index + size > stream_size(stream)) => try reading chunks
-    for (bool read_chunk = stream_chunk(stream);
-         read_chunk && index + size >= stream->pipe.cache.size;
-         read_chunk = stream_chunk(stream))
-      continue;
-
     if (index + size > stream_size(stream))
-      return SV(NULL, 0);
-    return SV((char *)vec_data(&stream->pipe.cache) + index, size);
+    {
+      // => try reading chunks till either we drop or we have enough space
+      for (bool read_chunk = stream_chunk(stream);
+           read_chunk && index + size >= stream->pipe.cache.size;
+           read_chunk = stream_chunk(stream))
+        continue;
+    }
+    break;
   }
+  case STREAM_TYPE_STRING:
+  case STREAM_TYPE_FILE:
+    break;
   default:
-    assert("Unreachable");
-    return SV(NULL, 0);
+    FAIL("Unreachable");
   }
+
+  sv_t sv = stream_sv_abs(stream);
+  sv      = sv_chop_left(sv, index);
+  sv      = sv_truncate(sv, size);
+  return sv;
 }
 
 sv_t stream_till(stream_t *stream, const char *str)
 {
   if (stream_eoc(stream))
     return SV(NULL, 0);
-  u64 current_position = stream->position;
-  for (char c = stream_peek(stream); c != '\0' && strchr(str, c) == NULL;
-       c      = stream_next(stream))
-    continue;
-  u64 size = stream->position - current_position;
-  if (size == 0)
-    return SV(NULL, 0);
-  return stream_substr_abs(stream, current_position, size - 1);
+
+  sv_t cur_sv = stream_sv(stream);
+  sv_t sv     = sv_till(cur_sv, str);
+  stream_seek_forward(stream, sv.size);
+  switch (stream->type)
+  {
+  case STREAM_TYPE_FILE:
+  case STREAM_TYPE_STRING:
+    return sv;
+  case STREAM_TYPE_PIPE:
+  {
+    if (cur_sv.size > sv.size)
+      return sv;
+
+    // Build a substring by hand while chunking data.
+    u64 index, size;
+    for (index = stream->position - sv.size, size = sv.size;
+         cur_sv.size == sv.size; size += sv.size)
+    {
+      cur_sv = stream_sv(stream);
+      sv     = sv_till(cur_sv, str);
+      stream_seek_forward(stream, sv.size);
+      if (sv.size == 0)
+        // Must stop if this has happened; nothing else to pick up.
+        break;
+    }
+    return stream_substr_abs(stream, index, size);
+  }
+  default:
+    FAIL("Unreachable");
+  }
 }
 
 sv_t stream_while(stream_t *stream, const char *str)
 {
   if (stream_eoc(stream))
     return SV(NULL, 0);
-  u64 current_position = stream->position;
-  for (char c = stream_peek(stream); c != '\0' && strchr(str, c);
-       c      = stream_next(stream))
-    continue;
-  u64 size = stream->position - current_position;
-  if (size == 0)
-    return SV(NULL, 0);
-  return stream_substr_abs(stream, current_position, size - 1);
+
+  sv_t cur_sv = stream_sv(stream);
+  sv_t sv     = sv_while(cur_sv, str);
+  stream_seek_forward(stream, sv.size);
+  switch (stream->type)
+  {
+  case STREAM_TYPE_FILE:
+  case STREAM_TYPE_STRING:
+    return sv;
+  case STREAM_TYPE_PIPE:
+  {
+    if (cur_sv.size > sv.size)
+      return sv;
+
+    // Build a substring by hand while chunking data.
+    u64 index, size;
+    for (index = stream->position - sv.size, size = sv.size;
+         cur_sv.size == sv.size; size += sv.size)
+    {
+      cur_sv = stream_sv(stream);
+      sv     = sv_while(cur_sv, str);
+      stream_seek_forward(stream, sv.size);
+      if (sv.size == 0)
+        // Must stop if this has happened; nothing else to pick up.
+        break;
+    }
+    return stream_substr_abs(stream, index, size);
+  }
+  default:
+    FAIL("Unreachable");
+  }
 }
 
 void stream_line_col(stream_t *stream, u64 *line, u64 *col)
 {
   if (!stream || !line || !col)
     return;
-  // Go through the cache, byte by byte.
-  char *cache = NULL;
-  u64 size    = 0;
-  if (stream->type == STREAM_TYPE_STRING)
-  {
-    cache = stream->string.data;
-    size  = stream->string.size;
-  }
-  else
-  {
-    cache = (char *)vec_data(&stream->pipe.cache);
-    size  = stream->pipe.cache.size;
-  }
+
+  // Generate a string view from the stream of exactly the content /upto/
+  // stream.postion.
+  sv_t sv = stream_sv_abs(stream);
+  sv      = sv_truncate(sv, stream->position + 1);
 
   *line = 1;
   *col  = 0;
-  for (u64 i = 0; i < size; ++i)
+  // TODO: Could this be faster?  Does it matter?
+  for (u64 i = 0; i < sv.size; ++i)
   {
-    char c = cache[i];
+    char c = sv.data[i];
     if (c == '\n')
     {
       *line += 1;

src/sv.c

@@ -60,7 +60,7 @@ sv_t sv_till(sv_t sv, const char *reject)
 
   if (offset == sv.size)
     return sv;
-  return sv_chop_right(sv, sv.size - offset);
+  return sv_truncate(sv, offset);
 }
 
 sv_t sv_while(sv_t sv, const char *accept)
@@ -75,7 +75,7 @@ sv_t sv_while(sv_t sv, const char *accept)
 
   if (offset == sv.size)
     return sv;
-  return sv_chop_right(sv, sv.size - offset);
+  return sv_truncate(sv, offset);
 }
 
 /* Copyright (C) 2025, 2026 Aryadev Chavali

test/test_stream.c

@@ -82,7 +82,7 @@ void stream_test_string(void)
          test_strings[i].size);
     TEST(!stream_eoc(&stream), "Not end of content already");
 
-    stream_stop(&stream);
+    stream_free(&stream);
     TEST(strncmp(copy.data, test_strings[i].data, copy.size) == 0,
          "Freeing a stream does not free the underlying memory it was derived "
          "from");
@@ -96,7 +96,7 @@ void stream_test_string(void)
        stream_err_to_cstr(err));
   TEST(stream_size(&stream) == 0, "NULL stream size is 0");
   TEST(stream_eoc(&stream), "NULL stream is always at end of content");
-  stream_stop(&stream);
+  stream_free(&stream);
 
   TEST_END();
 }
@@ -113,9 +113,8 @@ void stream_test_file(void)
       TEST(err == STREAM_ERR_OK, "Expected initialisating to be okay: %s",
            stream_err_to_cstr(err));
     }
-    TEST(stream_size(&stream) == 0, "Stream doesn't read on init: size = %lu",
-         stream_size(&stream));
     TEST(!stream_eoc(&stream), "Stream should not be at the EoC from init.");
+    stream_free(&stream);
   }
 
   // try to initialise the stream again but against a nonexistent file - we're
@@ -164,7 +163,7 @@ void stream_test_peek_next(void)
          "(%c)",
          c3, c2);
 
-    stream_stop(&stream);
+    stream_free(&stream);
   }
 
   // Invalid streams
@@ -181,7 +180,7 @@ void stream_test_peek_next(void)
          "Next on an invalid stream should not affect position (%lu -> %lu)",
          old_position, stream.position);
 
-    stream_stop(&stream);
+    stream_free(&stream);
   }
   TEST_END();
 }
@@ -210,7 +209,7 @@ void stream_test_seek(void)
          "stream (%lu -> %lu)",
          old_position, stream.position);
 
-    stream_stop(&stream);
+    stream_free(&stream);
   }
 
   // Valid streams
@@ -268,7 +267,7 @@ void stream_test_seek(void)
         "above.",
         stream.position);
 
-    stream_stop(&stream);
+    stream_free(&stream);
   }
 
   TEST_END();
@@ -302,7 +301,7 @@ void stream_test_substr(void)
            position, size);
     }
 
-    stream_stop(&stream);
+    stream_free(&stream);
   }
 
   // Taking substrings of valid streams
@@ -377,7 +376,7 @@ void stream_test_substr(void)
       }
     }
 
-    stream_stop(&stream);
+    stream_free(&stream);
   }
   TEST_END();
 }