ref: 8435a29c4e0db7295d750c87e624374c8bea907f
parent: b7fe78cad8a951aa08c3133478da175eb377e2fd
author: Rangi <remy.oukaour+rangi42@gmail.com>
date: Wed Nov 24 12:18:35 EST 2021
Turn the `readChars` macro into a `readInternal` function This macro was only used twice, and the second usage did some unnecessary work.
--- a/src/asm/lexer.c
+++ b/src/asm/lexer.c
@@ -808,6 +808,19 @@
return str;
}
+static size_t readInternal(size_t bufIndex, size_t nbChars)
+{+ // This buffer overflow made me lose WEEKS of my life. Never again.
+ assert(bufIndex + nbChars <= LEXER_BUF_SIZE);
+ ssize_t nbReadChars = read(lexerState->fd, &lexerState->buf[bufIndex], nbChars);
+
+ if (nbReadChars == -1)
+ fatalerror("Error while reading \"%s\": %s\n", lexerState->path, strerror(errno));+
+ // `nbReadChars` cannot be negative, so it's fine to cast to `size_t`
+ return (size_t)nbReadChars;
+}
+
/* We only need one character of lookahead, for macro arguments */
static int peekInternal(uint8_t distance)
{@@ -839,42 +852,31 @@
/* Compute the index we'll start writing to */
size_t writeIndex = (lexerState->index + lexerState->nbChars) % LEXER_BUF_SIZE;
- ssize_t nbCharsRead = 0, totalCharsRead = 0;
-#define readChars(size) do { \- /* This buffer overflow made me lose WEEKS of my life. Never again. */ \
- assert(writeIndex + (size) <= LEXER_BUF_SIZE); \
- nbCharsRead = read(lexerState->fd, &lexerState->buf[writeIndex], (size)); \
- if (nbCharsRead == -1) \
- fatalerror("Error while reading \"%s\": %s\n", lexerState->path, strerror(errno)); \- totalCharsRead += nbCharsRead; \
- writeIndex += nbCharsRead; \
- if (writeIndex == LEXER_BUF_SIZE) \
- writeIndex = 0; \
- target -= nbCharsRead; \
-} while (0)
-
/* If the range to fill passes over the buffer wrapping point, we need two reads */
if (writeIndex + target > LEXER_BUF_SIZE) {size_t nbExpectedChars = LEXER_BUF_SIZE - writeIndex;
+ size_t nbReadChars = readInternal(writeIndex, nbExpectedChars);
- readChars(nbExpectedChars);
+ lexerState->nbChars += nbReadChars;
+
+ writeIndex += nbReadChars;
+ if (writeIndex == LEXER_BUF_SIZE)
+ writeIndex = 0;
+
// If the read was incomplete, don't perform a second read
- // `nbCharsRead` cannot be negative, so it's fine to cast to `size_t`
- if ((size_t)nbCharsRead < nbExpectedChars)
+ target -= nbReadChars;
+ if (nbReadChars < nbExpectedChars)
target = 0;
}
if (target != 0)
- readChars(target);
+ lexerState->nbChars += readInternal(writeIndex, target);
-#undef readChars
-
- lexerState->nbChars += totalCharsRead;
-
/* If there aren't enough chars even after refilling, give up */
if (lexerState->nbChars <= distance)
return EOF;
}
+
return (unsigned char)lexerState->buf[(lexerState->index + distance) % LEXER_BUF_SIZE];
}