56 lines
2.5 KiB
C
56 lines
2.5 KiB
C
#pragma once
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#include "esp_err.h"
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#include <sys/types.h> // For ssize_t
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/**
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* @brief Initializes the SPIFFS filesystem.
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* This function should be called once before any file operations.
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* @return ESP_OK on success, error code otherwise.
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*/
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esp_err_t storage_init(void);
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/**
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* @brief Unregisters the SPIFFS filesystem.
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* This function should be called once when file operations are finished.
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*/
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void storage_uninit(void);
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/**
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* @brief Reads a chunk of data from a file on SPIFFS.
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* This function maintains internal state (file pointer) to allow reading
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* the same file chunk by chunk across multiple calls.
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*
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* @param filename The path to the file to read (e.g., "/storage/my_file.txt").
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* Must be the same filename for consecutive calls to read the same file.
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* @param buffer Buffer to store the read data. Must be large enough for max_bytes.
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* @param max_bytes The maximum number of bytes to read in this call. Must be > 0.
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* @return The number of bytes read on success (>= 0).
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* Returns 0 when the end of the file is reached.
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* Returns a negative value on error:
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* -1: Invalid input parameters (filename, buffer is NULL, or max_bytes is 0).
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* -2: Failed to open the file (first call for this filename).
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* -3: Filename mismatch with the currently open file (subsequent call).
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* -4: Read error occurred.
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*/
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ssize_t storage_read(const char *filename, char *buffer, size_t max_bytes);
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/**
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* @brief Reads a chunk of data from a file on SPIFFS, starting at a specific offset.
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* This function is stateless regarding an internally managed file pointer for sequential reads;
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* it opens, seeks, reads, and closes the file on each call.
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*
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* @param filename The path to the file to read (e.g., "/storage/my_file.txt").
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* @param buffer Buffer to store the read data. Must be large enough for nbytes.
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* @param offset The offset in the file to start reading from.
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* @param nbytes The maximum number of bytes to read in this call. Must be > 0.
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* @return The number of bytes read on success (>= 0).
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* Returns 0 when the end of the file is reached from the given offset.
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* Returns a negative value on error:
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* -1: Invalid input parameters (filename, buffer is NULL, nbytes is 0, or offset is negative).
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* -2: Failed to open the file.
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* -5: Seek error occurred.
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* -4: Read error occurred.
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*/
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ssize_t storage_read_at(const char *filename, char *buffer, off_t offset, size_t nbytes);
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