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QR-Code-generator
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Rewrote comments for top-level QR-encoding functions in C, to correspond better to other language ports.

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pull/143/head
Project Nayuki 3 years ago
parent 33af976bba
commit f3705873ab
1 changed files with 113 additions and 54 deletions
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167
c/qrcodegen.h
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@ -151,28 +151,38 @@ struct qrcodegen_Segment {
* Encodes the given text string to a QR Code, returning true if successful.
* If the data is too long to fit in any version in the given range
* at the given ECC level, then false is returned.
* - The input text must be encoded in UTF-8 and contain no NULs.
* - The variables ecl and mask must correspond to enum constant values.
* - Requires 1 <= minVersion <= maxVersion <= 40.
* - About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion):
* - Before calling the function:
* - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow
* reading and writing; hence each array must have a length of at least len.
* - The two ranges must not overlap (aliasing).
* - The initial state of both ranges can be uninitialized
* because the function always writes before reading.
* - After the function returns:
* - Both ranges have no guarantee on which elements are initialized and what values are stored.
* - tempBuffer contains no useful data and should be treated as entirely uninitialized.
* - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
* - If successful, the resulting QR Code may use numeric,
* alphanumeric, or byte mode to encode the text.
* - In the most optimistic case, a QR Code at version 40 with low ECC
* can hold any UTF-8 string up to 2953 bytes, or any alphanumeric string
* up to 4296 characters, or any digit string up to 7089 characters.
* These numbers represent the hard upper limit of the QR Code standard.
* - Please consult the QR Code specification for information on
* data capacities per version, ECC level, and text encoding mode.
*
* The input text must be encoded in UTF-8 and contain no NULs.
* Requires 1 <= minVersion <= maxVersion <= 40.
*
* The smallest possible QR Code version within the given range is automatically
* chosen for the output. Iff boostEcl is true, then the ECC level of the result
* may be higher than the ecl argument if it can be done without increasing the
* version. The mask is either between qrcodegen_Mask_0 to 7 to force that mask, or
* qrcodegen_Mask_AUTO to automatically choose an appropriate mask (which may be slow).
*
* About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion):
* - Before calling the function:
* - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow
* reading and writing; hence each array must have a length of at least len.
* - The two ranges must not overlap (aliasing).
* - The initial state of both ranges can be uninitialized
* because the function always writes before reading.
* - After the function returns:
* - Both ranges have no guarantee on which elements are initialized and what values are stored.
* - tempBuffer contains no useful data and should be treated as entirely uninitialized.
* - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
*
* If successful, the resulting QR Code may use numeric,
* alphanumeric, or byte mode to encode the text.
*
* In the most optimistic case, a QR Code at version 40 with low ECC
* can hold any UTF-8 string up to 2953 bytes, or any alphanumeric string
* up to 4296 characters, or any digit string up to 7089 characters.
* These numbers represent the hard upper limit of the QR Code standard.
*
* Please consult the QR Code specification for information on
* data capacities per version, ECC level, and text encoding mode.
*/
bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
@ -182,26 +192,36 @@ bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode
* Encodes the given binary data to a QR Code, returning true if successful.
* If the data is too long to fit in any version in the given range
* at the given ECC level, then false is returned.
* - The variables ecl and mask must correspond to enum constant values.
* - Requires 1 <= minVersion <= maxVersion <= 40.
* - About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion):
* - Before calling the function:
* - The array ranges dataAndTemp[0 : len] and qrcode[0 : len] must allow
* reading and writing; hence each array must have a length of at least len.
* - The two ranges must not overlap (aliasing).
* - The input array range dataAndTemp[0 : dataLen] should normally be
* valid UTF-8 text, but is not required by the QR Code standard.
* - The initial state of dataAndTemp[dataLen : len] and qrcode[0 : len]
* can be uninitialized because the function always writes before reading.
* - After the function returns:
* - Both ranges have no guarantee on which elements are initialized and what values are stored.
* - dataAndTemp contains no useful data and should be treated as entirely uninitialized.
* - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
* - If successful, the resulting QR Code will use byte mode to encode the data.
* - In the most optimistic case, a QR Code at version 40 with low ECC can hold any byte
* sequence up to length 2953. This is the hard upper limit of the QR Code standard.
* - Please consult the QR Code specification for information on
* data capacities per version, ECC level, and text encoding mode.
*
* Requires 1 <= minVersion <= maxVersion <= 40.
*
* The smallest possible QR Code version within the given range is automatically
* chosen for the output. Iff boostEcl is true, then the ECC level of the result
* may be higher than the ecl argument if it can be done without increasing the
* version. The mask is either between qrcodegen_Mask_0 to 7 to force that mask, or
* qrcodegen_Mask_AUTO to automatically choose an appropriate mask (which may be slow).
*
* About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion):
* - Before calling the function:
* - The array ranges dataAndTemp[0 : len] and qrcode[0 : len] must allow
* reading and writing; hence each array must have a length of at least len.
* - The two ranges must not overlap (aliasing).
* - The input array range dataAndTemp[0 : dataLen] should normally be
* valid UTF-8 text, but is not required by the QR Code standard.
* - The initial state of dataAndTemp[dataLen : len] and qrcode[0 : len]
* can be uninitialized because the function always writes before reading.
* - After the function returns:
* - Both ranges have no guarantee on which elements are initialized and what values are stored.
* - dataAndTemp contains no useful data and should be treated as entirely uninitialized.
* - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
*
* If successful, the resulting QR Code will use byte mode to encode the data.
*
* In the most optimistic case, a QR Code at version 40 with low ECC can hold any byte
* sequence up to length 2953. This is the hard upper limit of the QR Code standard.
*
* Please consult the QR Code specification for information on
* data capacities per version, ECC level, and text encoding mode.
*/
bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
@ -210,35 +230,74 @@ bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcod
/*---- Functions (low level) to generate QR Codes ----*/
/*
* Renders a QR Code representing the given segments at the given error correction level.
* The smallest possible QR Code version is automatically chosen for the output. Returns true if
* QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level
* of the result may be higher than the ecl argument if it can be done without increasing the version.
* Encodes the given segments to a QR Code, returning true if successful.
* If the data is too long to fit in any version at the given ECC level,
* then false is returned.
*
* The smallest possible QR Code version is automatically chosen for
* the output. The ECC level of the result may be higher than the
* ecl argument if it can be done without increasing the version.
*
* About the byte arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX):
* - Before calling the function:
* - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow
* reading and writing; hence each array must have a length of at least len.
* - The two ranges must not overlap (aliasing).
* - The initial state of both ranges can be uninitialized
* because the function always writes before reading.
* - The input array segs can contain segments whose data buffers overlap with tempBuffer.
* - After the function returns:
* - Both ranges have no guarantee on which elements are initialized and what values are stored.
* - tempBuffer contains no useful data and should be treated as entirely uninitialized.
* - Any segment whose data buffer overlaps with tempBuffer[0 : len]
* must be treated as having invalid values in that array.
* - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
*
* Please consult the QR Code specification for information on
* data capacities per version, ECC level, and text encoding mode.
*
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and byte) to encode text in less space.
* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
* result in them being clobbered, but the QR Code output will still be correct.
* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
*/
bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
/*
* Renders a QR Code representing the given segments with the given encoding parameters.
* Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions.
* Encodes the given segments to a QR Code, returning true if successful.
* If the data is too long to fit in any version in the given range
* at the given ECC level, then false is returned.
*
* Requires 1 <= minVersion <= maxVersion <= 40.
*
* The smallest possible QR Code version within the given range is automatically
* chosen for the output. Iff boostEcl is true, then the ECC level of the result
* may be higher than the ecl argument if it can be done without increasing the
* version. The mask is either between qrcodegen_Mask_0 to 7 to force that mask, or
* qrcodegen_Mask_AUTO to automatically choose an appropriate mask (which may be slow).
*
* About the byte arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX):
* - Before calling the function:
* - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow
* reading and writing; hence each array must have a length of at least len.
* - The two ranges must not overlap (aliasing).
* - The initial state of both ranges can be uninitialized
* because the function always writes before reading.
* - The input array segs can contain segments whose data buffers overlap with tempBuffer.
* - After the function returns:
* - Both ranges have no guarantee on which elements are initialized and what values are stored.
* - tempBuffer contains no useful data and should be treated as entirely uninitialized.
* - Any segment whose data buffer overlaps with tempBuffer[0 : len]
* must be treated as having invalid values in that array.
* - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
*
* Please consult the QR Code specification for information on
* data capacities per version, ECC level, and text encoding mode.
*
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and byte) to encode text in less space.
* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
* result in them being clobbered, but the QR Code output will still be correct.
* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
*/
bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);

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