From 3f5ba5908117cf3351702c144a2509f4bf48d75b Mon Sep 17 00:00:00 2001 From: David Robillard Date: Fri, 14 Aug 2020 15:51:12 +0200 Subject: Clean up and separate internal headers --- src/stack.h | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 src/stack.h (limited to 'src/stack.h') diff --git a/src/stack.h b/src/stack.h new file mode 100644 index 00000000..e95c5770 --- /dev/null +++ b/src/stack.h @@ -0,0 +1,117 @@ +/* + Copyright 2011-2020 David Robillard + + Permission to use, copy, modify, and/or distribute this software for any + purpose with or without fee is hereby granted, provided that the above + copyright notice and this permission notice appear in all copies. + + THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + +#ifndef SERD_STACK_H +#define SERD_STACK_H + +#include "serd_internal.h" + +#include +#include +#include + +/** An offset to start the stack at. Note 0 is reserved for NULL. */ +#define SERD_STACK_BOTTOM sizeof(void*) + +/** A dynamic stack in memory. */ +typedef struct { + uint8_t* buf; ///< Stack memory + size_t buf_size; ///< Allocated size of buf (>= size) + size_t size; ///< Conceptual size of stack in buf +} SerdStack; + +/** An offset to start the stack at. Note 0 is reserved for NULL. */ +#define SERD_STACK_BOTTOM sizeof(void*) + +static inline SerdStack +serd_stack_new(size_t size) +{ + SerdStack stack; + stack.buf = (uint8_t*)calloc(size, 1); + stack.buf_size = size; + stack.size = SERD_STACK_BOTTOM; + return stack; +} + +static inline bool +serd_stack_is_empty(SerdStack* stack) +{ + return stack->size <= SERD_STACK_BOTTOM; +} + +static inline void +serd_stack_free(SerdStack* stack) +{ + free(stack->buf); + stack->buf = NULL; + stack->buf_size = 0; + stack->size = 0; +} + +static inline uint8_t* +serd_stack_push(SerdStack* stack, size_t n_bytes) +{ + const size_t new_size = stack->size + n_bytes; + if (stack->buf_size < new_size) { + stack->buf_size += (stack->buf_size >> 1); // *= 1.5 + stack->buf = (uint8_t*)realloc(stack->buf, stack->buf_size); + } + uint8_t* const ret = (stack->buf + stack->size); + stack->size = new_size; + return ret; +} + +static inline void +serd_stack_pop(SerdStack* stack, size_t n_bytes) +{ + assert(stack->size >= n_bytes); + stack->size -= n_bytes; +} + +static inline void* +serd_stack_push_aligned(SerdStack* stack, size_t n_bytes, size_t align) +{ + // Push one byte to ensure space for a pad count + serd_stack_push(stack, 1); + + // Push padding if necessary + const size_t pad = align - stack->size % align; + if (pad > 0) { + serd_stack_push(stack, pad); + } + + // Set top of stack to pad count so we can properly pop later + assert(pad < UINT8_MAX); + stack->buf[stack->size - 1] = (uint8_t)pad; + + // Push requested space at aligned location + return serd_stack_push(stack, n_bytes); +} + +static inline void +serd_stack_pop_aligned(SerdStack* stack, size_t n_bytes) +{ + // Pop requested space down to aligned location + serd_stack_pop(stack, n_bytes); + + // Get amount of padding from top of stack + const uint8_t pad = stack->buf[stack->size - 1]; + + // Pop padding and pad count + serd_stack_pop(stack, pad + 1u); +} + +#endif // SERD_STACK_H -- cgit v1.2.1