From f32bcbd7f471799befdacf36ac8864c4ce328dfb Mon Sep 17 00:00:00 2001 From: Přemysl Eric Janouch Date: Sat, 10 Feb 2024 07:02:54 +0100 Subject: Add helper functions for reading binary numbers And make use of them. --- LICENSE | 2 +- liberty.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++-------------- 2 files changed, 60 insertions(+), 18 deletions(-) diff --git a/LICENSE b/LICENSE index 0610bbd..d58be36 100644 --- a/LICENSE +++ b/LICENSE @@ -1,4 +1,4 @@ -Copyright (c) 2014 - 2023, Přemysl Eric Janouch +Copyright (c) 2014 - 2024, Přemysl Eric Janouch Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted. diff --git a/liberty.c b/liberty.c index e438c34..390d40b 100644 --- a/liberty.c +++ b/liberty.c @@ -1,7 +1,7 @@ /* * liberty.c: the ultimate C unlibrary * - * Copyright (c) 2014 - 2022, Přemysl Eric Janouch + * Copyright (c) 2014 - 2024, Přemysl Eric Janouch * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted. @@ -652,6 +652,60 @@ str_pack_u64 (struct str *self, uint64_t x) #define str_pack_i32(self, x) str_pack_u32 ((self), (uint32_t) (x)) #define str_pack_i64(self, x) str_pack_u64 ((self), (uint64_t) (x)) +// --- Reading binary numbers -------------------------------------------------- + +// Doing this byte by byte prevents unaligned memory access issues. + +static uint64_t +peek_u64be (const uint8_t *p) +{ + return (uint64_t) p[0] << 56 | (uint64_t) p[1] << 48 + | (uint64_t) p[2] << 40 | (uint64_t) p[3] << 32 + | (uint64_t) p[4] << 24 | (uint64_t) p[5] << 16 | p[6] << 8 | p[7]; +} + +static uint32_t +peek_u32be (const uint8_t *p) +{ + return (uint32_t) p[0] << 24 | (uint32_t) p[1] << 16 | p[2] << 8 | p[3]; +} + +static uint16_t +peek_u16be (const uint8_t *p) +{ + return (uint16_t) p[0] << 8 | p[1]; +} + +static uint64_t +peek_u64le (const uint8_t *p) +{ + return (uint64_t) p[7] << 56 | (uint64_t) p[6] << 48 + | (uint64_t) p[5] << 40 | (uint64_t) p[4] << 32 + | (uint64_t) p[3] << 24 | (uint64_t) p[2] << 16 | p[1] << 8 | p[0]; +} + +static uint32_t +peek_u32le (const uint8_t *p) +{ + return (uint32_t) p[3] << 24 | (uint32_t) p[2] << 16 | p[1] << 8 | p[0]; +} + +static uint16_t +peek_u16le (const uint8_t *p) +{ + return (uint16_t) p[1] << 8 | p[0]; +} + +struct peeker +{ + uint64_t (*u64) (const uint8_t *); + uint32_t (*u32) (const uint8_t *); + uint16_t (*u16) (const uint8_t *); +}; + +static const struct peeker peeker_be = {peek_u64be, peek_u32be, peek_u16be}; +static const struct peeker peeker_le = {peek_u64le, peek_u32le, peek_u16le}; + // --- Errors ------------------------------------------------------------------ // Error reporting utilities. Inspired by GError, only much simpler. @@ -2503,12 +2557,7 @@ msg_reader_get (struct msg_reader *self, size_t *len) return NULL; uint8_t *x = (uint8_t *) self->buf.str + self->offset; - uint64_t msg_len - = (uint64_t) x[0] << 56 | (uint64_t) x[1] << 48 - | (uint64_t) x[2] << 40 | (uint64_t) x[3] << 32 - | (uint64_t) x[4] << 24 | (uint64_t) x[5] << 16 - | (uint64_t) x[6] << 8 | (uint64_t) x[7]; - + uint64_t msg_len = peek_u64be (x); if (msg_len < sizeof msg_len) { // The message is shorter than its header @@ -2573,8 +2622,7 @@ static bool msg_unpacker_u16 (struct msg_unpacker *self, uint16_t *value) { UNPACKER_INT_BEGIN - *value - = (uint16_t) x[0] << 8 | (uint16_t) x[1]; + *value = peek_u16be (x); return true; } @@ -2582,9 +2630,7 @@ static bool msg_unpacker_u32 (struct msg_unpacker *self, uint32_t *value) { UNPACKER_INT_BEGIN - *value - = (uint32_t) x[0] << 24 | (uint32_t) x[1] << 16 - | (uint32_t) x[2] << 8 | (uint32_t) x[3]; + *value = peek_u32be (x); return true; } @@ -2592,11 +2638,7 @@ static bool msg_unpacker_u64 (struct msg_unpacker *self, uint64_t *value) { UNPACKER_INT_BEGIN - *value - = (uint64_t) x[0] << 56 | (uint64_t) x[1] << 48 - | (uint64_t) x[2] << 40 | (uint64_t) x[3] << 32 - | (uint64_t) x[4] << 24 | (uint64_t) x[5] << 16 - | (uint64_t) x[6] << 8 | (uint64_t) x[7]; + *value = peek_u64be (x); return true; } -- cgit v1.2.3-70-g09d2